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Diffstat (limited to '')
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 3016 |
1 files changed, 3016 insertions, 0 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c new file mode 100644 index 000000000..c74eaf255 --- /dev/null +++ b/drivers/tty/serial/amba-pl011.c @@ -0,0 +1,3016 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Driver for AMBA serial ports + * + * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. + * + * Copyright 1999 ARM Limited + * Copyright (C) 2000 Deep Blue Solutions Ltd. + * Copyright (C) 2010 ST-Ericsson SA + * + * This is a generic driver for ARM AMBA-type serial ports. They + * have a lot of 16550-like features, but are not register compatible. + * Note that although they do have CTS, DCD and DSR inputs, they do + * not have an RI input, nor do they have DTR or RTS outputs. If + * required, these have to be supplied via some other means (eg, GPIO) + * and hooked into this driver. + */ + +#include <linux/module.h> +#include <linux/ioport.h> +#include <linux/init.h> +#include <linux/console.h> +#include <linux/sysrq.h> +#include <linux/device.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/serial_core.h> +#include <linux/serial.h> +#include <linux/amba/bus.h> +#include <linux/amba/serial.h> +#include <linux/clk.h> +#include <linux/slab.h> +#include <linux/dmaengine.h> +#include <linux/dma-mapping.h> +#include <linux/scatterlist.h> +#include <linux/delay.h> +#include <linux/types.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/pinctrl/consumer.h> +#include <linux/sizes.h> +#include <linux/io.h> +#include <linux/acpi.h> + +#define UART_NR 14 + +#define SERIAL_AMBA_MAJOR 204 +#define SERIAL_AMBA_MINOR 64 +#define SERIAL_AMBA_NR UART_NR + +#define AMBA_ISR_PASS_LIMIT 256 + +#define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE) +#define UART_DUMMY_DR_RX (1 << 16) + +enum { + REG_DR, + REG_ST_DMAWM, + REG_ST_TIMEOUT, + REG_FR, + REG_LCRH_RX, + REG_LCRH_TX, + REG_IBRD, + REG_FBRD, + REG_CR, + REG_IFLS, + REG_IMSC, + REG_RIS, + REG_MIS, + REG_ICR, + REG_DMACR, + REG_ST_XFCR, + REG_ST_XON1, + REG_ST_XON2, + REG_ST_XOFF1, + REG_ST_XOFF2, + REG_ST_ITCR, + REG_ST_ITIP, + REG_ST_ABCR, + REG_ST_ABIMSC, + + /* The size of the array - must be last */ + REG_ARRAY_SIZE, +}; + +static u16 pl011_std_offsets[REG_ARRAY_SIZE] = { + [REG_DR] = UART01x_DR, + [REG_FR] = UART01x_FR, + [REG_LCRH_RX] = UART011_LCRH, + [REG_LCRH_TX] = UART011_LCRH, + [REG_IBRD] = UART011_IBRD, + [REG_FBRD] = UART011_FBRD, + [REG_CR] = UART011_CR, + [REG_IFLS] = UART011_IFLS, + [REG_IMSC] = UART011_IMSC, + [REG_RIS] = UART011_RIS, + [REG_MIS] = UART011_MIS, + [REG_ICR] = UART011_ICR, + [REG_DMACR] = UART011_DMACR, +}; + +/* There is by now at least one vendor with differing details, so handle it */ +struct vendor_data { + const u16 *reg_offset; + unsigned int ifls; + unsigned int fr_busy; + unsigned int fr_dsr; + unsigned int fr_cts; + unsigned int fr_ri; + unsigned int inv_fr; + bool access_32b; + bool oversampling; + bool dma_threshold; + bool cts_event_workaround; + bool always_enabled; + bool fixed_options; + + unsigned int (*get_fifosize)(struct amba_device *dev); +}; + +static unsigned int get_fifosize_arm(struct amba_device *dev) +{ + return amba_rev(dev) < 3 ? 16 : 32; +} + +static struct vendor_data vendor_arm = { + .reg_offset = pl011_std_offsets, + .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8, + .fr_busy = UART01x_FR_BUSY, + .fr_dsr = UART01x_FR_DSR, + .fr_cts = UART01x_FR_CTS, + .fr_ri = UART011_FR_RI, + .oversampling = false, + .dma_threshold = false, + .cts_event_workaround = false, + .always_enabled = false, + .fixed_options = false, + .get_fifosize = get_fifosize_arm, +}; + +static const struct vendor_data vendor_sbsa = { + .reg_offset = pl011_std_offsets, + .fr_busy = UART01x_FR_BUSY, + .fr_dsr = UART01x_FR_DSR, + .fr_cts = UART01x_FR_CTS, + .fr_ri = UART011_FR_RI, + .access_32b = true, + .oversampling = false, + .dma_threshold = false, + .cts_event_workaround = false, + .always_enabled = true, + .fixed_options = true, +}; + +#ifdef CONFIG_ACPI_SPCR_TABLE +static const struct vendor_data vendor_qdt_qdf2400_e44 = { + .reg_offset = pl011_std_offsets, + .fr_busy = UART011_FR_TXFE, + .fr_dsr = UART01x_FR_DSR, + .fr_cts = UART01x_FR_CTS, + .fr_ri = UART011_FR_RI, + .inv_fr = UART011_FR_TXFE, + .access_32b = true, + .oversampling = false, + .dma_threshold = false, + .cts_event_workaround = false, + .always_enabled = true, + .fixed_options = true, +}; +#endif + +static u16 pl011_st_offsets[REG_ARRAY_SIZE] = { + [REG_DR] = UART01x_DR, + [REG_ST_DMAWM] = ST_UART011_DMAWM, + [REG_ST_TIMEOUT] = ST_UART011_TIMEOUT, + [REG_FR] = UART01x_FR, + [REG_LCRH_RX] = ST_UART011_LCRH_RX, + [REG_LCRH_TX] = ST_UART011_LCRH_TX, + [REG_IBRD] = UART011_IBRD, + [REG_FBRD] = UART011_FBRD, + [REG_CR] = UART011_CR, + [REG_IFLS] = UART011_IFLS, + [REG_IMSC] = UART011_IMSC, + [REG_RIS] = UART011_RIS, + [REG_MIS] = UART011_MIS, + [REG_ICR] = UART011_ICR, + [REG_DMACR] = UART011_DMACR, + [REG_ST_XFCR] = ST_UART011_XFCR, + [REG_ST_XON1] = ST_UART011_XON1, + [REG_ST_XON2] = ST_UART011_XON2, + [REG_ST_XOFF1] = ST_UART011_XOFF1, + [REG_ST_XOFF2] = ST_UART011_XOFF2, + [REG_ST_ITCR] = ST_UART011_ITCR, + [REG_ST_ITIP] = ST_UART011_ITIP, + [REG_ST_ABCR] = ST_UART011_ABCR, + [REG_ST_ABIMSC] = ST_UART011_ABIMSC, +}; + +static unsigned int get_fifosize_st(struct amba_device *dev) +{ + return 64; +} + +static struct vendor_data vendor_st = { + .reg_offset = pl011_st_offsets, + .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF, + .fr_busy = UART01x_FR_BUSY, + .fr_dsr = UART01x_FR_DSR, + .fr_cts = UART01x_FR_CTS, + .fr_ri = UART011_FR_RI, + .oversampling = true, + .dma_threshold = true, + .cts_event_workaround = true, + .always_enabled = false, + .fixed_options = false, + .get_fifosize = get_fifosize_st, +}; + +/* Deals with DMA transactions */ + +struct pl011_dmabuf { + dma_addr_t dma; + size_t len; + char *buf; +}; + +struct pl011_dmarx_data { + struct dma_chan *chan; + struct completion complete; + bool use_buf_b; + struct pl011_dmabuf dbuf_a; + struct pl011_dmabuf dbuf_b; + dma_cookie_t cookie; + bool running; + struct timer_list timer; + unsigned int last_residue; + unsigned long last_jiffies; + bool auto_poll_rate; + unsigned int poll_rate; + unsigned int poll_timeout; +}; + +struct pl011_dmatx_data { + struct dma_chan *chan; + dma_addr_t dma; + size_t len; + char *buf; + bool queued; +}; + +/* + * We wrap our port structure around the generic uart_port. + */ +struct uart_amba_port { + struct uart_port port; + const u16 *reg_offset; + struct clk *clk; + const struct vendor_data *vendor; + unsigned int dmacr; /* dma control reg */ + unsigned int im; /* interrupt mask */ + unsigned int old_status; + unsigned int fifosize; /* vendor-specific */ + unsigned int fixed_baud; /* vendor-set fixed baud rate */ + char type[12]; + bool rs485_tx_started; + unsigned int rs485_tx_drain_interval; /* usecs */ +#ifdef CONFIG_DMA_ENGINE + /* DMA stuff */ + bool using_tx_dma; + bool using_rx_dma; + struct pl011_dmarx_data dmarx; + struct pl011_dmatx_data dmatx; + bool dma_probed; +#endif +}; + +static unsigned int pl011_tx_empty(struct uart_port *port); + +static unsigned int pl011_reg_to_offset(const struct uart_amba_port *uap, + unsigned int reg) +{ + return uap->reg_offset[reg]; +} + +static unsigned int pl011_read(const struct uart_amba_port *uap, + unsigned int reg) +{ + void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); + + return (uap->port.iotype == UPIO_MEM32) ? + readl_relaxed(addr) : readw_relaxed(addr); +} + +static void pl011_write(unsigned int val, const struct uart_amba_port *uap, + unsigned int reg) +{ + void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); + + if (uap->port.iotype == UPIO_MEM32) + writel_relaxed(val, addr); + else + writew_relaxed(val, addr); +} + +/* + * Reads up to 256 characters from the FIFO or until it's empty and + * inserts them into the TTY layer. Returns the number of characters + * read from the FIFO. + */ +static int pl011_fifo_to_tty(struct uart_amba_port *uap) +{ + unsigned int ch, flag, fifotaken; + int sysrq; + u16 status; + + for (fifotaken = 0; fifotaken != 256; fifotaken++) { + status = pl011_read(uap, REG_FR); + if (status & UART01x_FR_RXFE) + break; + + /* Take chars from the FIFO and update status */ + ch = pl011_read(uap, REG_DR) | UART_DUMMY_DR_RX; + flag = TTY_NORMAL; + uap->port.icount.rx++; + + if (unlikely(ch & UART_DR_ERROR)) { + if (ch & UART011_DR_BE) { + ch &= ~(UART011_DR_FE | UART011_DR_PE); + uap->port.icount.brk++; + if (uart_handle_break(&uap->port)) + continue; + } else if (ch & UART011_DR_PE) + uap->port.icount.parity++; + else if (ch & UART011_DR_FE) + uap->port.icount.frame++; + if (ch & UART011_DR_OE) + uap->port.icount.overrun++; + + ch &= uap->port.read_status_mask; + + if (ch & UART011_DR_BE) + flag = TTY_BREAK; + else if (ch & UART011_DR_PE) + flag = TTY_PARITY; + else if (ch & UART011_DR_FE) + flag = TTY_FRAME; + } + + spin_unlock(&uap->port.lock); + sysrq = uart_handle_sysrq_char(&uap->port, ch & 255); + spin_lock(&uap->port.lock); + + if (!sysrq) + uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag); + } + + return fifotaken; +} + + +/* + * All the DMA operation mode stuff goes inside this ifdef. + * This assumes that you have a generic DMA device interface, + * no custom DMA interfaces are supported. + */ +#ifdef CONFIG_DMA_ENGINE + +#define PL011_DMA_BUFFER_SIZE PAGE_SIZE + +static int pl011_dmabuf_init(struct dma_chan *chan, struct pl011_dmabuf *db, + enum dma_data_direction dir) +{ + db->buf = dma_alloc_coherent(chan->device->dev, PL011_DMA_BUFFER_SIZE, + &db->dma, GFP_KERNEL); + if (!db->buf) + return -ENOMEM; + db->len = PL011_DMA_BUFFER_SIZE; + + return 0; +} + +static void pl011_dmabuf_free(struct dma_chan *chan, struct pl011_dmabuf *db, + enum dma_data_direction dir) +{ + if (db->buf) { + dma_free_coherent(chan->device->dev, + PL011_DMA_BUFFER_SIZE, db->buf, db->dma); + } +} + +static void pl011_dma_probe(struct uart_amba_port *uap) +{ + /* DMA is the sole user of the platform data right now */ + struct amba_pl011_data *plat = dev_get_platdata(uap->port.dev); + struct device *dev = uap->port.dev; + struct dma_slave_config tx_conf = { + .dst_addr = uap->port.mapbase + + pl011_reg_to_offset(uap, REG_DR), + .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .direction = DMA_MEM_TO_DEV, + .dst_maxburst = uap->fifosize >> 1, + .device_fc = false, + }; + struct dma_chan *chan; + dma_cap_mask_t mask; + + uap->dma_probed = true; + chan = dma_request_chan(dev, "tx"); + if (IS_ERR(chan)) { + if (PTR_ERR(chan) == -EPROBE_DEFER) { + uap->dma_probed = false; + return; + } + + /* We need platform data */ + if (!plat || !plat->dma_filter) { + dev_info(uap->port.dev, "no DMA platform data\n"); + return; + } + + /* Try to acquire a generic DMA engine slave TX channel */ + dma_cap_zero(mask); + dma_cap_set(DMA_SLAVE, mask); + + chan = dma_request_channel(mask, plat->dma_filter, + plat->dma_tx_param); + if (!chan) { + dev_err(uap->port.dev, "no TX DMA channel!\n"); + return; + } + } + + dmaengine_slave_config(chan, &tx_conf); + uap->dmatx.chan = chan; + + dev_info(uap->port.dev, "DMA channel TX %s\n", + dma_chan_name(uap->dmatx.chan)); + + /* Optionally make use of an RX channel as well */ + chan = dma_request_slave_channel(dev, "rx"); + + if (!chan && plat && plat->dma_rx_param) { + chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param); + + if (!chan) { + dev_err(uap->port.dev, "no RX DMA channel!\n"); + return; + } + } + + if (chan) { + struct dma_slave_config rx_conf = { + .src_addr = uap->port.mapbase + + pl011_reg_to_offset(uap, REG_DR), + .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE, + .direction = DMA_DEV_TO_MEM, + .src_maxburst = uap->fifosize >> 2, + .device_fc = false, + }; + struct dma_slave_caps caps; + + /* + * Some DMA controllers provide information on their capabilities. + * If the controller does, check for suitable residue processing + * otherwise assime all is well. + */ + if (0 == dma_get_slave_caps(chan, &caps)) { + if (caps.residue_granularity == + DMA_RESIDUE_GRANULARITY_DESCRIPTOR) { + dma_release_channel(chan); + dev_info(uap->port.dev, + "RX DMA disabled - no residue processing\n"); + return; + } + } + dmaengine_slave_config(chan, &rx_conf); + uap->dmarx.chan = chan; + + uap->dmarx.auto_poll_rate = false; + if (plat && plat->dma_rx_poll_enable) { + /* Set poll rate if specified. */ + if (plat->dma_rx_poll_rate) { + uap->dmarx.auto_poll_rate = false; + uap->dmarx.poll_rate = plat->dma_rx_poll_rate; + } else { + /* + * 100 ms defaults to poll rate if not + * specified. This will be adjusted with + * the baud rate at set_termios. + */ + uap->dmarx.auto_poll_rate = true; + uap->dmarx.poll_rate = 100; + } + /* 3 secs defaults poll_timeout if not specified. */ + if (plat->dma_rx_poll_timeout) + uap->dmarx.poll_timeout = + plat->dma_rx_poll_timeout; + else + uap->dmarx.poll_timeout = 3000; + } else if (!plat && dev->of_node) { + uap->dmarx.auto_poll_rate = of_property_read_bool( + dev->of_node, "auto-poll"); + if (uap->dmarx.auto_poll_rate) { + u32 x; + + if (0 == of_property_read_u32(dev->of_node, + "poll-rate-ms", &x)) + uap->dmarx.poll_rate = x; + else + uap->dmarx.poll_rate = 100; + if (0 == of_property_read_u32(dev->of_node, + "poll-timeout-ms", &x)) + uap->dmarx.poll_timeout = x; + else + uap->dmarx.poll_timeout = 3000; + } + } + dev_info(uap->port.dev, "DMA channel RX %s\n", + dma_chan_name(uap->dmarx.chan)); + } +} + +static void pl011_dma_remove(struct uart_amba_port *uap) +{ + if (uap->dmatx.chan) + dma_release_channel(uap->dmatx.chan); + if (uap->dmarx.chan) + dma_release_channel(uap->dmarx.chan); +} + +/* Forward declare these for the refill routine */ +static int pl011_dma_tx_refill(struct uart_amba_port *uap); +static void pl011_start_tx_pio(struct uart_amba_port *uap); + +/* + * The current DMA TX buffer has been sent. + * Try to queue up another DMA buffer. + */ +static void pl011_dma_tx_callback(void *data) +{ + struct uart_amba_port *uap = data; + struct pl011_dmatx_data *dmatx = &uap->dmatx; + unsigned long flags; + u16 dmacr; + + spin_lock_irqsave(&uap->port.lock, flags); + if (uap->dmatx.queued) + dma_unmap_single(dmatx->chan->device->dev, dmatx->dma, + dmatx->len, DMA_TO_DEVICE); + + dmacr = uap->dmacr; + uap->dmacr = dmacr & ~UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + + /* + * If TX DMA was disabled, it means that we've stopped the DMA for + * some reason (eg, XOFF received, or we want to send an X-char.) + * + * Note: we need to be careful here of a potential race between DMA + * and the rest of the driver - if the driver disables TX DMA while + * a TX buffer completing, we must update the tx queued status to + * get further refills (hence we check dmacr). + */ + if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) || + uart_circ_empty(&uap->port.state->xmit)) { + uap->dmatx.queued = false; + spin_unlock_irqrestore(&uap->port.lock, flags); + return; + } + + if (pl011_dma_tx_refill(uap) <= 0) + /* + * We didn't queue a DMA buffer for some reason, but we + * have data pending to be sent. Re-enable the TX IRQ. + */ + pl011_start_tx_pio(uap); + + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +/* + * Try to refill the TX DMA buffer. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * 1 if we queued up a TX DMA buffer. + * 0 if we didn't want to handle this by DMA + * <0 on error + */ +static int pl011_dma_tx_refill(struct uart_amba_port *uap) +{ + struct pl011_dmatx_data *dmatx = &uap->dmatx; + struct dma_chan *chan = dmatx->chan; + struct dma_device *dma_dev = chan->device; + struct dma_async_tx_descriptor *desc; + struct circ_buf *xmit = &uap->port.state->xmit; + unsigned int count; + + /* + * Try to avoid the overhead involved in using DMA if the + * transaction fits in the first half of the FIFO, by using + * the standard interrupt handling. This ensures that we + * issue a uart_write_wakeup() at the appropriate time. + */ + count = uart_circ_chars_pending(xmit); + if (count < (uap->fifosize >> 1)) { + uap->dmatx.queued = false; + return 0; + } + + /* + * Bodge: don't send the last character by DMA, as this + * will prevent XON from notifying us to restart DMA. + */ + count -= 1; + + /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */ + if (count > PL011_DMA_BUFFER_SIZE) + count = PL011_DMA_BUFFER_SIZE; + + if (xmit->tail < xmit->head) + memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count); + else { + size_t first = UART_XMIT_SIZE - xmit->tail; + size_t second; + + if (first > count) + first = count; + second = count - first; + + memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first); + if (second) + memcpy(&dmatx->buf[first], &xmit->buf[0], second); + } + + dmatx->len = count; + dmatx->dma = dma_map_single(dma_dev->dev, dmatx->buf, count, + DMA_TO_DEVICE); + if (dmatx->dma == DMA_MAPPING_ERROR) { + uap->dmatx.queued = false; + dev_dbg(uap->port.dev, "unable to map TX DMA\n"); + return -EBUSY; + } + + desc = dmaengine_prep_slave_single(chan, dmatx->dma, dmatx->len, DMA_MEM_TO_DEV, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + if (!desc) { + dma_unmap_single(dma_dev->dev, dmatx->dma, dmatx->len, DMA_TO_DEVICE); + uap->dmatx.queued = false; + /* + * If DMA cannot be used right now, we complete this + * transaction via IRQ and let the TTY layer retry. + */ + dev_dbg(uap->port.dev, "TX DMA busy\n"); + return -EBUSY; + } + + /* Some data to go along to the callback */ + desc->callback = pl011_dma_tx_callback; + desc->callback_param = uap; + + /* All errors should happen at prepare time */ + dmaengine_submit(desc); + + /* Fire the DMA transaction */ + dma_dev->device_issue_pending(chan); + + uap->dmacr |= UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + uap->dmatx.queued = true; + + /* + * Now we know that DMA will fire, so advance the ring buffer + * with the stuff we just dispatched. + */ + xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); + uap->port.icount.tx += count; + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&uap->port); + + return 1; +} + +/* + * We received a transmit interrupt without a pending X-char but with + * pending characters. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * false if we want to use PIO to transmit + * true if we queued a DMA buffer + */ +static bool pl011_dma_tx_irq(struct uart_amba_port *uap) +{ + if (!uap->using_tx_dma) + return false; + + /* + * If we already have a TX buffer queued, but received a + * TX interrupt, it will be because we've just sent an X-char. + * Ensure the TX DMA is enabled and the TX IRQ is disabled. + */ + if (uap->dmatx.queued) { + uap->dmacr |= UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + uap->im &= ~UART011_TXIM; + pl011_write(uap->im, uap, REG_IMSC); + return true; + } + + /* + * We don't have a TX buffer queued, so try to queue one. + * If we successfully queued a buffer, mask the TX IRQ. + */ + if (pl011_dma_tx_refill(uap) > 0) { + uap->im &= ~UART011_TXIM; + pl011_write(uap->im, uap, REG_IMSC); + return true; + } + return false; +} + +/* + * Stop the DMA transmit (eg, due to received XOFF). + * Locking: called with port lock held and IRQs disabled. + */ +static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) +{ + if (uap->dmatx.queued) { + uap->dmacr &= ~UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + } +} + +/* + * Try to start a DMA transmit, or in the case of an XON/OFF + * character queued for send, try to get that character out ASAP. + * Locking: called with port lock held and IRQs disabled. + * Returns: + * false if we want the TX IRQ to be enabled + * true if we have a buffer queued + */ +static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) +{ + u16 dmacr; + + if (!uap->using_tx_dma) + return false; + + if (!uap->port.x_char) { + /* no X-char, try to push chars out in DMA mode */ + bool ret = true; + + if (!uap->dmatx.queued) { + if (pl011_dma_tx_refill(uap) > 0) { + uap->im &= ~UART011_TXIM; + pl011_write(uap->im, uap, REG_IMSC); + } else + ret = false; + } else if (!(uap->dmacr & UART011_TXDMAE)) { + uap->dmacr |= UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + } + return ret; + } + + /* + * We have an X-char to send. Disable DMA to prevent it loading + * the TX fifo, and then see if we can stuff it into the FIFO. + */ + dmacr = uap->dmacr; + uap->dmacr &= ~UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + + if (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) { + /* + * No space in the FIFO, so enable the transmit interrupt + * so we know when there is space. Note that once we've + * loaded the character, we should just re-enable DMA. + */ + return false; + } + + pl011_write(uap->port.x_char, uap, REG_DR); + uap->port.icount.tx++; + uap->port.x_char = 0; + + /* Success - restore the DMA state */ + uap->dmacr = dmacr; + pl011_write(dmacr, uap, REG_DMACR); + + return true; +} + +/* + * Flush the transmit buffer. + * Locking: called with port lock held and IRQs disabled. + */ +static void pl011_dma_flush_buffer(struct uart_port *port) +__releases(&uap->port.lock) +__acquires(&uap->port.lock) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + if (!uap->using_tx_dma) + return; + + dmaengine_terminate_async(uap->dmatx.chan); + + if (uap->dmatx.queued) { + dma_unmap_single(uap->dmatx.chan->device->dev, uap->dmatx.dma, + uap->dmatx.len, DMA_TO_DEVICE); + uap->dmatx.queued = false; + uap->dmacr &= ~UART011_TXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + } +} + +static void pl011_dma_rx_callback(void *data); + +static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) +{ + struct dma_chan *rxchan = uap->dmarx.chan; + struct pl011_dmarx_data *dmarx = &uap->dmarx; + struct dma_async_tx_descriptor *desc; + struct pl011_dmabuf *dbuf; + + if (!rxchan) + return -EIO; + + /* Start the RX DMA job */ + dbuf = uap->dmarx.use_buf_b ? + &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a; + desc = dmaengine_prep_slave_single(rxchan, dbuf->dma, dbuf->len, + DMA_DEV_TO_MEM, + DMA_PREP_INTERRUPT | DMA_CTRL_ACK); + /* + * If the DMA engine is busy and cannot prepare a + * channel, no big deal, the driver will fall back + * to interrupt mode as a result of this error code. + */ + if (!desc) { + uap->dmarx.running = false; + dmaengine_terminate_all(rxchan); + return -EBUSY; + } + + /* Some data to go along to the callback */ + desc->callback = pl011_dma_rx_callback; + desc->callback_param = uap; + dmarx->cookie = dmaengine_submit(desc); + dma_async_issue_pending(rxchan); + + uap->dmacr |= UART011_RXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + uap->dmarx.running = true; + + uap->im &= ~UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + + return 0; +} + +/* + * This is called when either the DMA job is complete, or + * the FIFO timeout interrupt occurred. This must be called + * with the port spinlock uap->port.lock held. + */ +static void pl011_dma_rx_chars(struct uart_amba_port *uap, + u32 pending, bool use_buf_b, + bool readfifo) +{ + struct tty_port *port = &uap->port.state->port; + struct pl011_dmabuf *dbuf = use_buf_b ? + &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a; + int dma_count = 0; + u32 fifotaken = 0; /* only used for vdbg() */ + + struct pl011_dmarx_data *dmarx = &uap->dmarx; + int dmataken = 0; + + if (uap->dmarx.poll_rate) { + /* The data can be taken by polling */ + dmataken = dbuf->len - dmarx->last_residue; + /* Recalculate the pending size */ + if (pending >= dmataken) + pending -= dmataken; + } + + /* Pick the remain data from the DMA */ + if (pending) { + + /* + * First take all chars in the DMA pipe, then look in the FIFO. + * Note that tty_insert_flip_buf() tries to take as many chars + * as it can. + */ + dma_count = tty_insert_flip_string(port, dbuf->buf + dmataken, + pending); + + uap->port.icount.rx += dma_count; + if (dma_count < pending) + dev_warn(uap->port.dev, + "couldn't insert all characters (TTY is full?)\n"); + } + + /* Reset the last_residue for Rx DMA poll */ + if (uap->dmarx.poll_rate) + dmarx->last_residue = dbuf->len; + + /* + * Only continue with trying to read the FIFO if all DMA chars have + * been taken first. + */ + if (dma_count == pending && readfifo) { + /* Clear any error flags */ + pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS | + UART011_FEIS, uap, REG_ICR); + + /* + * If we read all the DMA'd characters, and we had an + * incomplete buffer, that could be due to an rx error, or + * maybe we just timed out. Read any pending chars and check + * the error status. + * + * Error conditions will only occur in the FIFO, these will + * trigger an immediate interrupt and stop the DMA job, so we + * will always find the error in the FIFO, never in the DMA + * buffer. + */ + fifotaken = pl011_fifo_to_tty(uap); + } + + dev_vdbg(uap->port.dev, + "Took %d chars from DMA buffer and %d chars from the FIFO\n", + dma_count, fifotaken); + tty_flip_buffer_push(port); +} + +static void pl011_dma_rx_irq(struct uart_amba_port *uap) +{ + struct pl011_dmarx_data *dmarx = &uap->dmarx; + struct dma_chan *rxchan = dmarx->chan; + struct pl011_dmabuf *dbuf = dmarx->use_buf_b ? + &dmarx->dbuf_b : &dmarx->dbuf_a; + size_t pending; + struct dma_tx_state state; + enum dma_status dmastat; + + /* + * Pause the transfer so we can trust the current counter, + * do this before we pause the PL011 block, else we may + * overflow the FIFO. + */ + if (dmaengine_pause(rxchan)) + dev_err(uap->port.dev, "unable to pause DMA transfer\n"); + dmastat = rxchan->device->device_tx_status(rxchan, + dmarx->cookie, &state); + if (dmastat != DMA_PAUSED) + dev_err(uap->port.dev, "unable to pause DMA transfer\n"); + + /* Disable RX DMA - incoming data will wait in the FIFO */ + uap->dmacr &= ~UART011_RXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); + uap->dmarx.running = false; + + pending = dbuf->len - state.residue; + BUG_ON(pending > PL011_DMA_BUFFER_SIZE); + /* Then we terminate the transfer - we now know our residue */ + dmaengine_terminate_all(rxchan); + + /* + * This will take the chars we have so far and insert + * into the framework. + */ + pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true); + + /* Switch buffer & re-trigger DMA job */ + dmarx->use_buf_b = !dmarx->use_buf_b; + if (pl011_dma_rx_trigger_dma(uap)) { + dev_dbg(uap->port.dev, "could not retrigger RX DMA job " + "fall back to interrupt mode\n"); + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + } +} + +static void pl011_dma_rx_callback(void *data) +{ + struct uart_amba_port *uap = data; + struct pl011_dmarx_data *dmarx = &uap->dmarx; + struct dma_chan *rxchan = dmarx->chan; + bool lastbuf = dmarx->use_buf_b; + struct pl011_dmabuf *dbuf = dmarx->use_buf_b ? + &dmarx->dbuf_b : &dmarx->dbuf_a; + size_t pending; + struct dma_tx_state state; + int ret; + + /* + * This completion interrupt occurs typically when the + * RX buffer is totally stuffed but no timeout has yet + * occurred. When that happens, we just want the RX + * routine to flush out the secondary DMA buffer while + * we immediately trigger the next DMA job. + */ + spin_lock_irq(&uap->port.lock); + /* + * Rx data can be taken by the UART interrupts during + * the DMA irq handler. So we check the residue here. + */ + rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state); + pending = dbuf->len - state.residue; + BUG_ON(pending > PL011_DMA_BUFFER_SIZE); + /* Then we terminate the transfer - we now know our residue */ + dmaengine_terminate_all(rxchan); + + uap->dmarx.running = false; + dmarx->use_buf_b = !lastbuf; + ret = pl011_dma_rx_trigger_dma(uap); + + pl011_dma_rx_chars(uap, pending, lastbuf, false); + spin_unlock_irq(&uap->port.lock); + /* + * Do this check after we picked the DMA chars so we don't + * get some IRQ immediately from RX. + */ + if (ret) { + dev_dbg(uap->port.dev, "could not retrigger RX DMA job " + "fall back to interrupt mode\n"); + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + } +} + +/* + * Stop accepting received characters, when we're shutting down or + * suspending this port. + * Locking: called with port lock held and IRQs disabled. + */ +static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) +{ + if (!uap->using_rx_dma) + return; + + /* FIXME. Just disable the DMA enable */ + uap->dmacr &= ~UART011_RXDMAE; + pl011_write(uap->dmacr, uap, REG_DMACR); +} + +/* + * Timer handler for Rx DMA polling. + * Every polling, It checks the residue in the dma buffer and transfer + * data to the tty. Also, last_residue is updated for the next polling. + */ +static void pl011_dma_rx_poll(struct timer_list *t) +{ + struct uart_amba_port *uap = from_timer(uap, t, dmarx.timer); + struct tty_port *port = &uap->port.state->port; + struct pl011_dmarx_data *dmarx = &uap->dmarx; + struct dma_chan *rxchan = uap->dmarx.chan; + unsigned long flags; + unsigned int dmataken = 0; + unsigned int size = 0; + struct pl011_dmabuf *dbuf; + int dma_count; + struct dma_tx_state state; + + dbuf = dmarx->use_buf_b ? &uap->dmarx.dbuf_b : &uap->dmarx.dbuf_a; + rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state); + if (likely(state.residue < dmarx->last_residue)) { + dmataken = dbuf->len - dmarx->last_residue; + size = dmarx->last_residue - state.residue; + dma_count = tty_insert_flip_string(port, dbuf->buf + dmataken, + size); + if (dma_count == size) + dmarx->last_residue = state.residue; + dmarx->last_jiffies = jiffies; + } + tty_flip_buffer_push(port); + + /* + * If no data is received in poll_timeout, the driver will fall back + * to interrupt mode. We will retrigger DMA at the first interrupt. + */ + if (jiffies_to_msecs(jiffies - dmarx->last_jiffies) + > uap->dmarx.poll_timeout) { + + spin_lock_irqsave(&uap->port.lock, flags); + pl011_dma_rx_stop(uap); + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + spin_unlock_irqrestore(&uap->port.lock, flags); + + uap->dmarx.running = false; + dmaengine_terminate_all(rxchan); + del_timer(&uap->dmarx.timer); + } else { + mod_timer(&uap->dmarx.timer, + jiffies + msecs_to_jiffies(uap->dmarx.poll_rate)); + } +} + +static void pl011_dma_startup(struct uart_amba_port *uap) +{ + int ret; + + if (!uap->dma_probed) + pl011_dma_probe(uap); + + if (!uap->dmatx.chan) + return; + + uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL | __GFP_DMA); + if (!uap->dmatx.buf) { + dev_err(uap->port.dev, "no memory for DMA TX buffer\n"); + uap->port.fifosize = uap->fifosize; + return; + } + + uap->dmatx.len = PL011_DMA_BUFFER_SIZE; + + /* The DMA buffer is now the FIFO the TTY subsystem can use */ + uap->port.fifosize = PL011_DMA_BUFFER_SIZE; + uap->using_tx_dma = true; + + if (!uap->dmarx.chan) + goto skip_rx; + + /* Allocate and map DMA RX buffers */ + ret = pl011_dmabuf_init(uap->dmarx.chan, &uap->dmarx.dbuf_a, + DMA_FROM_DEVICE); + if (ret) { + dev_err(uap->port.dev, "failed to init DMA %s: %d\n", + "RX buffer A", ret); + goto skip_rx; + } + + ret = pl011_dmabuf_init(uap->dmarx.chan, &uap->dmarx.dbuf_b, + DMA_FROM_DEVICE); + if (ret) { + dev_err(uap->port.dev, "failed to init DMA %s: %d\n", + "RX buffer B", ret); + pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_a, + DMA_FROM_DEVICE); + goto skip_rx; + } + + uap->using_rx_dma = true; + +skip_rx: + /* Turn on DMA error (RX/TX will be enabled on demand) */ + uap->dmacr |= UART011_DMAONERR; + pl011_write(uap->dmacr, uap, REG_DMACR); + + /* + * ST Micro variants has some specific dma burst threshold + * compensation. Set this to 16 bytes, so burst will only + * be issued above/below 16 bytes. + */ + if (uap->vendor->dma_threshold) + pl011_write(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16, + uap, REG_ST_DMAWM); + + if (uap->using_rx_dma) { + if (pl011_dma_rx_trigger_dma(uap)) + dev_dbg(uap->port.dev, "could not trigger initial " + "RX DMA job, fall back to interrupt mode\n"); + if (uap->dmarx.poll_rate) { + timer_setup(&uap->dmarx.timer, pl011_dma_rx_poll, 0); + mod_timer(&uap->dmarx.timer, + jiffies + + msecs_to_jiffies(uap->dmarx.poll_rate)); + uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE; + uap->dmarx.last_jiffies = jiffies; + } + } +} + +static void pl011_dma_shutdown(struct uart_amba_port *uap) +{ + if (!(uap->using_tx_dma || uap->using_rx_dma)) + return; + + /* Disable RX and TX DMA */ + while (pl011_read(uap, REG_FR) & uap->vendor->fr_busy) + cpu_relax(); + + spin_lock_irq(&uap->port.lock); + uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE); + pl011_write(uap->dmacr, uap, REG_DMACR); + spin_unlock_irq(&uap->port.lock); + + if (uap->using_tx_dma) { + /* In theory, this should already be done by pl011_dma_flush_buffer */ + dmaengine_terminate_all(uap->dmatx.chan); + if (uap->dmatx.queued) { + dma_unmap_single(uap->dmatx.chan->device->dev, + uap->dmatx.dma, uap->dmatx.len, + DMA_TO_DEVICE); + uap->dmatx.queued = false; + } + + kfree(uap->dmatx.buf); + uap->using_tx_dma = false; + } + + if (uap->using_rx_dma) { + dmaengine_terminate_all(uap->dmarx.chan); + /* Clean up the RX DMA */ + pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_a, DMA_FROM_DEVICE); + pl011_dmabuf_free(uap->dmarx.chan, &uap->dmarx.dbuf_b, DMA_FROM_DEVICE); + if (uap->dmarx.poll_rate) + del_timer_sync(&uap->dmarx.timer); + uap->using_rx_dma = false; + } +} + +static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) +{ + return uap->using_rx_dma; +} + +static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) +{ + return uap->using_rx_dma && uap->dmarx.running; +} + +#else +/* Blank functions if the DMA engine is not available */ +static inline void pl011_dma_remove(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_startup(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_shutdown(struct uart_amba_port *uap) +{ +} + +static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap) +{ + return false; +} + +static inline void pl011_dma_tx_stop(struct uart_amba_port *uap) +{ +} + +static inline bool pl011_dma_tx_start(struct uart_amba_port *uap) +{ + return false; +} + +static inline void pl011_dma_rx_irq(struct uart_amba_port *uap) +{ +} + +static inline void pl011_dma_rx_stop(struct uart_amba_port *uap) +{ +} + +static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap) +{ + return -EIO; +} + +static inline bool pl011_dma_rx_available(struct uart_amba_port *uap) +{ + return false; +} + +static inline bool pl011_dma_rx_running(struct uart_amba_port *uap) +{ + return false; +} + +#define pl011_dma_flush_buffer NULL +#endif + +static void pl011_rs485_tx_stop(struct uart_amba_port *uap) +{ + /* + * To be on the safe side only time out after twice as many iterations + * as fifo size. + */ + const int MAX_TX_DRAIN_ITERS = uap->port.fifosize * 2; + struct uart_port *port = &uap->port; + int i = 0; + u32 cr; + + /* Wait until hardware tx queue is empty */ + while (!pl011_tx_empty(port)) { + if (i > MAX_TX_DRAIN_ITERS) { + dev_warn(port->dev, + "timeout while draining hardware tx queue\n"); + break; + } + + udelay(uap->rs485_tx_drain_interval); + i++; + } + + if (port->rs485.delay_rts_after_send) + mdelay(port->rs485.delay_rts_after_send); + + cr = pl011_read(uap, REG_CR); + + if (port->rs485.flags & SER_RS485_RTS_AFTER_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + + /* Disable the transmitter and reenable the transceiver */ + cr &= ~UART011_CR_TXE; + cr |= UART011_CR_RXE; + pl011_write(cr, uap, REG_CR); + + uap->rs485_tx_started = false; +} + +static void pl011_stop_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + uap->im &= ~UART011_TXIM; + pl011_write(uap->im, uap, REG_IMSC); + pl011_dma_tx_stop(uap); + + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) + pl011_rs485_tx_stop(uap); +} + +static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq); + +/* Start TX with programmed I/O only (no DMA) */ +static void pl011_start_tx_pio(struct uart_amba_port *uap) +{ + if (pl011_tx_chars(uap, false)) { + uap->im |= UART011_TXIM; + pl011_write(uap->im, uap, REG_IMSC); + } +} + +static void pl011_start_tx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + if (!pl011_dma_tx_start(uap)) + pl011_start_tx_pio(uap); +} + +static void pl011_stop_rx(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM| + UART011_PEIM|UART011_BEIM|UART011_OEIM); + pl011_write(uap->im, uap, REG_IMSC); + + pl011_dma_rx_stop(uap); +} + +static void pl011_throttle_rx(struct uart_port *port) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + pl011_stop_rx(port); + spin_unlock_irqrestore(&port->lock, flags); +} + +static void pl011_enable_ms(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM; + pl011_write(uap->im, uap, REG_IMSC); +} + +static void pl011_rx_chars(struct uart_amba_port *uap) +__releases(&uap->port.lock) +__acquires(&uap->port.lock) +{ + pl011_fifo_to_tty(uap); + + spin_unlock(&uap->port.lock); + tty_flip_buffer_push(&uap->port.state->port); + /* + * If we were temporarily out of DMA mode for a while, + * attempt to switch back to DMA mode again. + */ + if (pl011_dma_rx_available(uap)) { + if (pl011_dma_rx_trigger_dma(uap)) { + dev_dbg(uap->port.dev, "could not trigger RX DMA job " + "fall back to interrupt mode again\n"); + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + } else { +#ifdef CONFIG_DMA_ENGINE + /* Start Rx DMA poll */ + if (uap->dmarx.poll_rate) { + uap->dmarx.last_jiffies = jiffies; + uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE; + mod_timer(&uap->dmarx.timer, + jiffies + + msecs_to_jiffies(uap->dmarx.poll_rate)); + } +#endif + } + } + spin_lock(&uap->port.lock); +} + +static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c, + bool from_irq) +{ + if (unlikely(!from_irq) && + pl011_read(uap, REG_FR) & UART01x_FR_TXFF) + return false; /* unable to transmit character */ + + pl011_write(c, uap, REG_DR); + uap->port.icount.tx++; + + return true; +} + +static void pl011_rs485_tx_start(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + u32 cr; + + /* Enable transmitter */ + cr = pl011_read(uap, REG_CR); + cr |= UART011_CR_TXE; + + /* Disable receiver if half-duplex */ + if (!(port->rs485.flags & SER_RS485_RX_DURING_TX)) + cr &= ~UART011_CR_RXE; + + if (port->rs485.flags & SER_RS485_RTS_ON_SEND) + cr &= ~UART011_CR_RTS; + else + cr |= UART011_CR_RTS; + + pl011_write(cr, uap, REG_CR); + + if (port->rs485.delay_rts_before_send) + mdelay(port->rs485.delay_rts_before_send); + + uap->rs485_tx_started = true; +} + +/* Returns true if tx interrupts have to be (kept) enabled */ +static bool pl011_tx_chars(struct uart_amba_port *uap, bool from_irq) +{ + struct circ_buf *xmit = &uap->port.state->xmit; + int count = uap->fifosize >> 1; + + if ((uap->port.rs485.flags & SER_RS485_ENABLED) && + !uap->rs485_tx_started) + pl011_rs485_tx_start(uap); + + if (uap->port.x_char) { + if (!pl011_tx_char(uap, uap->port.x_char, from_irq)) + return true; + uap->port.x_char = 0; + --count; + } + if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) { + pl011_stop_tx(&uap->port); + return false; + } + + /* If we are using DMA mode, try to send some characters. */ + if (pl011_dma_tx_irq(uap)) + return true; + + do { + if (likely(from_irq) && count-- == 0) + break; + + if (!pl011_tx_char(uap, xmit->buf[xmit->tail], from_irq)) + break; + + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + } while (!uart_circ_empty(xmit)); + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&uap->port); + + if (uart_circ_empty(xmit)) { + pl011_stop_tx(&uap->port); + return false; + } + return true; +} + +static void pl011_modem_status(struct uart_amba_port *uap) +{ + unsigned int status, delta; + + status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY; + + delta = status ^ uap->old_status; + uap->old_status = status; + + if (!delta) + return; + + if (delta & UART01x_FR_DCD) + uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD); + + if (delta & uap->vendor->fr_dsr) + uap->port.icount.dsr++; + + if (delta & uap->vendor->fr_cts) + uart_handle_cts_change(&uap->port, + status & uap->vendor->fr_cts); + + wake_up_interruptible(&uap->port.state->port.delta_msr_wait); +} + +static void check_apply_cts_event_workaround(struct uart_amba_port *uap) +{ + if (!uap->vendor->cts_event_workaround) + return; + + /* workaround to make sure that all bits are unlocked.. */ + pl011_write(0x00, uap, REG_ICR); + + /* + * WA: introduce 26ns(1 uart clk) delay before W1C; + * single apb access will incur 2 pclk(133.12Mhz) delay, + * so add 2 dummy reads + */ + pl011_read(uap, REG_ICR); + pl011_read(uap, REG_ICR); +} + +static irqreturn_t pl011_int(int irq, void *dev_id) +{ + struct uart_amba_port *uap = dev_id; + unsigned long flags; + unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT; + int handled = 0; + + spin_lock_irqsave(&uap->port.lock, flags); + status = pl011_read(uap, REG_RIS) & uap->im; + if (status) { + do { + check_apply_cts_event_workaround(uap); + + pl011_write(status & ~(UART011_TXIS|UART011_RTIS| + UART011_RXIS), + uap, REG_ICR); + + if (status & (UART011_RTIS|UART011_RXIS)) { + if (pl011_dma_rx_running(uap)) + pl011_dma_rx_irq(uap); + else + pl011_rx_chars(uap); + } + if (status & (UART011_DSRMIS|UART011_DCDMIS| + UART011_CTSMIS|UART011_RIMIS)) + pl011_modem_status(uap); + if (status & UART011_TXIS) + pl011_tx_chars(uap, true); + + if (pass_counter-- == 0) + break; + + status = pl011_read(uap, REG_RIS) & uap->im; + } while (status != 0); + handled = 1; + } + + spin_unlock_irqrestore(&uap->port.lock, flags); + + return IRQ_RETVAL(handled); +} + +static unsigned int pl011_tx_empty(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + /* Allow feature register bits to be inverted to work around errata */ + unsigned int status = pl011_read(uap, REG_FR) ^ uap->vendor->inv_fr; + + return status & (uap->vendor->fr_busy | UART01x_FR_TXFF) ? + 0 : TIOCSER_TEMT; +} + +static unsigned int pl011_get_mctrl(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int result = 0; + unsigned int status = pl011_read(uap, REG_FR); + +#define TIOCMBIT(uartbit, tiocmbit) \ + if (status & uartbit) \ + result |= tiocmbit + + TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR); + TIOCMBIT(uap->vendor->fr_dsr, TIOCM_DSR); + TIOCMBIT(uap->vendor->fr_cts, TIOCM_CTS); + TIOCMBIT(uap->vendor->fr_ri, TIOCM_RNG); +#undef TIOCMBIT + return result; +} + +static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + + cr = pl011_read(uap, REG_CR); + +#define TIOCMBIT(tiocmbit, uartbit) \ + if (mctrl & tiocmbit) \ + cr |= uartbit; \ + else \ + cr &= ~uartbit + + TIOCMBIT(TIOCM_RTS, UART011_CR_RTS); + TIOCMBIT(TIOCM_DTR, UART011_CR_DTR); + TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1); + TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2); + TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE); + + if (port->status & UPSTAT_AUTORTS) { + /* We need to disable auto-RTS if we want to turn RTS off */ + TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN); + } +#undef TIOCMBIT + + pl011_write(cr, uap, REG_CR); +} + +static void pl011_break_ctl(struct uart_port *port, int break_state) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned long flags; + unsigned int lcr_h; + + spin_lock_irqsave(&uap->port.lock, flags); + lcr_h = pl011_read(uap, REG_LCRH_TX); + if (break_state == -1) + lcr_h |= UART01x_LCRH_BRK; + else + lcr_h &= ~UART01x_LCRH_BRK; + pl011_write(lcr_h, uap, REG_LCRH_TX); + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +#ifdef CONFIG_CONSOLE_POLL + +static void pl011_quiesce_irqs(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + pl011_write(pl011_read(uap, REG_MIS), uap, REG_ICR); + /* + * There is no way to clear TXIM as this is "ready to transmit IRQ", so + * we simply mask it. start_tx() will unmask it. + * + * Note we can race with start_tx(), and if the race happens, the + * polling user might get another interrupt just after we clear it. + * But it should be OK and can happen even w/o the race, e.g. + * controller immediately got some new data and raised the IRQ. + * + * And whoever uses polling routines assumes that it manages the device + * (including tx queue), so we're also fine with start_tx()'s caller + * side. + */ + pl011_write(pl011_read(uap, REG_IMSC) & ~UART011_TXIM, uap, + REG_IMSC); +} + +static int pl011_get_poll_char(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int status; + + /* + * The caller might need IRQs lowered, e.g. if used with KDB NMI + * debugger. + */ + pl011_quiesce_irqs(port); + + status = pl011_read(uap, REG_FR); + if (status & UART01x_FR_RXFE) + return NO_POLL_CHAR; + + return pl011_read(uap, REG_DR); +} + +static void pl011_put_poll_char(struct uart_port *port, + unsigned char ch) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) + cpu_relax(); + + pl011_write(ch, uap, REG_DR); +} + +#endif /* CONFIG_CONSOLE_POLL */ + +static int pl011_hwinit(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + int retval; + + /* Optionaly enable pins to be muxed in and configured */ + pinctrl_pm_select_default_state(port->dev); + + /* + * Try to enable the clock producer. + */ + retval = clk_prepare_enable(uap->clk); + if (retval) + return retval; + + uap->port.uartclk = clk_get_rate(uap->clk); + + /* Clear pending error and receive interrupts */ + pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS | + UART011_FEIS | UART011_RTIS | UART011_RXIS, + uap, REG_ICR); + + /* + * Save interrupts enable mask, and enable RX interrupts in case if + * the interrupt is used for NMI entry. + */ + uap->im = pl011_read(uap, REG_IMSC); + pl011_write(UART011_RTIM | UART011_RXIM, uap, REG_IMSC); + + if (dev_get_platdata(uap->port.dev)) { + struct amba_pl011_data *plat; + + plat = dev_get_platdata(uap->port.dev); + if (plat->init) + plat->init(); + } + return 0; +} + +static bool pl011_split_lcrh(const struct uart_amba_port *uap) +{ + return pl011_reg_to_offset(uap, REG_LCRH_RX) != + pl011_reg_to_offset(uap, REG_LCRH_TX); +} + +static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h) +{ + pl011_write(lcr_h, uap, REG_LCRH_RX); + if (pl011_split_lcrh(uap)) { + int i; + /* + * Wait 10 PCLKs before writing LCRH_TX register, + * to get this delay write read only register 10 times + */ + for (i = 0; i < 10; ++i) + pl011_write(0xff, uap, REG_MIS); + pl011_write(lcr_h, uap, REG_LCRH_TX); + } +} + +static int pl011_allocate_irq(struct uart_amba_port *uap) +{ + pl011_write(uap->im, uap, REG_IMSC); + + return request_irq(uap->port.irq, pl011_int, IRQF_SHARED, "uart-pl011", uap); +} + +/* + * Enable interrupts, only timeouts when using DMA + * if initial RX DMA job failed, start in interrupt mode + * as well. + */ +static void pl011_enable_interrupts(struct uart_amba_port *uap) +{ + unsigned long flags; + unsigned int i; + + spin_lock_irqsave(&uap->port.lock, flags); + + /* Clear out any spuriously appearing RX interrupts */ + pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR); + + /* + * RXIS is asserted only when the RX FIFO transitions from below + * to above the trigger threshold. If the RX FIFO is already + * full to the threshold this can't happen and RXIS will now be + * stuck off. Drain the RX FIFO explicitly to fix this: + */ + for (i = 0; i < uap->fifosize * 2; ++i) { + if (pl011_read(uap, REG_FR) & UART01x_FR_RXFE) + break; + + pl011_read(uap, REG_DR); + } + + uap->im = UART011_RTIM; + if (!pl011_dma_rx_running(uap)) + uap->im |= UART011_RXIM; + pl011_write(uap->im, uap, REG_IMSC); + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +static void pl011_unthrottle_rx(struct uart_port *port) +{ + struct uart_amba_port *uap = container_of(port, struct uart_amba_port, port); + unsigned long flags; + + spin_lock_irqsave(&uap->port.lock, flags); + + uap->im = UART011_RTIM; + if (!pl011_dma_rx_running(uap)) + uap->im |= UART011_RXIM; + + pl011_write(uap->im, uap, REG_IMSC); + + spin_unlock_irqrestore(&uap->port.lock, flags); +} + +static int pl011_startup(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int cr; + int retval; + + retval = pl011_hwinit(port); + if (retval) + goto clk_dis; + + retval = pl011_allocate_irq(uap); + if (retval) + goto clk_dis; + + pl011_write(uap->vendor->ifls, uap, REG_IFLS); + + spin_lock_irq(&uap->port.lock); + + cr = pl011_read(uap, REG_CR); + cr &= UART011_CR_RTS | UART011_CR_DTR; + cr |= UART01x_CR_UARTEN | UART011_CR_RXE; + + if (!(port->rs485.flags & SER_RS485_ENABLED)) + cr |= UART011_CR_TXE; + + pl011_write(cr, uap, REG_CR); + + spin_unlock_irq(&uap->port.lock); + + /* + * initialise the old status of the modem signals + */ + uap->old_status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY; + + /* Startup DMA */ + pl011_dma_startup(uap); + + pl011_enable_interrupts(uap); + + return 0; + + clk_dis: + clk_disable_unprepare(uap->clk); + return retval; +} + +static int sbsa_uart_startup(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + int retval; + + retval = pl011_hwinit(port); + if (retval) + return retval; + + retval = pl011_allocate_irq(uap); + if (retval) + return retval; + + /* The SBSA UART does not support any modem status lines. */ + uap->old_status = 0; + + pl011_enable_interrupts(uap); + + return 0; +} + +static void pl011_shutdown_channel(struct uart_amba_port *uap, + unsigned int lcrh) +{ + unsigned long val; + + val = pl011_read(uap, lcrh); + val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN); + pl011_write(val, uap, lcrh); +} + +/* + * disable the port. It should not disable RTS and DTR. + * Also RTS and DTR state should be preserved to restore + * it during startup(). + */ +static void pl011_disable_uart(struct uart_amba_port *uap) +{ + unsigned int cr; + + uap->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); + spin_lock_irq(&uap->port.lock); + cr = pl011_read(uap, REG_CR); + cr &= UART011_CR_RTS | UART011_CR_DTR; + cr |= UART01x_CR_UARTEN | UART011_CR_TXE; + pl011_write(cr, uap, REG_CR); + spin_unlock_irq(&uap->port.lock); + + /* + * disable break condition and fifos + */ + pl011_shutdown_channel(uap, REG_LCRH_RX); + if (pl011_split_lcrh(uap)) + pl011_shutdown_channel(uap, REG_LCRH_TX); +} + +static void pl011_disable_interrupts(struct uart_amba_port *uap) +{ + spin_lock_irq(&uap->port.lock); + + /* mask all interrupts and clear all pending ones */ + uap->im = 0; + pl011_write(uap->im, uap, REG_IMSC); + pl011_write(0xffff, uap, REG_ICR); + + spin_unlock_irq(&uap->port.lock); +} + +static void pl011_shutdown(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + pl011_disable_interrupts(uap); + + pl011_dma_shutdown(uap); + + if ((port->rs485.flags & SER_RS485_ENABLED) && uap->rs485_tx_started) + pl011_rs485_tx_stop(uap); + + free_irq(uap->port.irq, uap); + + pl011_disable_uart(uap); + + /* + * Shut down the clock producer + */ + clk_disable_unprepare(uap->clk); + /* Optionally let pins go into sleep states */ + pinctrl_pm_select_sleep_state(port->dev); + + if (dev_get_platdata(uap->port.dev)) { + struct amba_pl011_data *plat; + + plat = dev_get_platdata(uap->port.dev); + if (plat->exit) + plat->exit(); + } + + if (uap->port.ops->flush_buffer) + uap->port.ops->flush_buffer(port); +} + +static void sbsa_uart_shutdown(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + pl011_disable_interrupts(uap); + + free_irq(uap->port.irq, uap); + + if (uap->port.ops->flush_buffer) + uap->port.ops->flush_buffer(port); +} + +static void +pl011_setup_status_masks(struct uart_port *port, struct ktermios *termios) +{ + port->read_status_mask = UART011_DR_OE | 255; + if (termios->c_iflag & INPCK) + port->read_status_mask |= UART011_DR_FE | UART011_DR_PE; + if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) + port->read_status_mask |= UART011_DR_BE; + + /* + * Characters to ignore + */ + port->ignore_status_mask = 0; + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE; + if (termios->c_iflag & IGNBRK) { + port->ignore_status_mask |= UART011_DR_BE; + /* + * If we're ignoring parity and break indicators, + * ignore overruns too (for real raw support). + */ + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= UART011_DR_OE; + } + + /* + * Ignore all characters if CREAD is not set. + */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= UART_DUMMY_DR_RX; +} + +static void +pl011_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned int lcr_h, old_cr; + unsigned long flags; + unsigned int baud, quot, clkdiv; + unsigned int bits; + + if (uap->vendor->oversampling) + clkdiv = 8; + else + clkdiv = 16; + + /* + * Ask the core to calculate the divisor for us. + */ + baud = uart_get_baud_rate(port, termios, old, 0, + port->uartclk / clkdiv); +#ifdef CONFIG_DMA_ENGINE + /* + * Adjust RX DMA polling rate with baud rate if not specified. + */ + if (uap->dmarx.auto_poll_rate) + uap->dmarx.poll_rate = DIV_ROUND_UP(10000000, baud); +#endif + + if (baud > port->uartclk/16) + quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud); + else + quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud); + + switch (termios->c_cflag & CSIZE) { + case CS5: + lcr_h = UART01x_LCRH_WLEN_5; + break; + case CS6: + lcr_h = UART01x_LCRH_WLEN_6; + break; + case CS7: + lcr_h = UART01x_LCRH_WLEN_7; + break; + default: // CS8 + lcr_h = UART01x_LCRH_WLEN_8; + break; + } + if (termios->c_cflag & CSTOPB) + lcr_h |= UART01x_LCRH_STP2; + if (termios->c_cflag & PARENB) { + lcr_h |= UART01x_LCRH_PEN; + if (!(termios->c_cflag & PARODD)) + lcr_h |= UART01x_LCRH_EPS; + if (termios->c_cflag & CMSPAR) + lcr_h |= UART011_LCRH_SPS; + } + if (uap->fifosize > 1) + lcr_h |= UART01x_LCRH_FEN; + + bits = tty_get_frame_size(termios->c_cflag); + + spin_lock_irqsave(&port->lock, flags); + + /* + * Update the per-port timeout. + */ + uart_update_timeout(port, termios->c_cflag, baud); + + /* + * Calculate the approximated time it takes to transmit one character + * with the given baud rate. We use this as the poll interval when we + * wait for the tx queue to empty. + */ + uap->rs485_tx_drain_interval = DIV_ROUND_UP(bits * 1000 * 1000, baud); + + pl011_setup_status_masks(port, termios); + + if (UART_ENABLE_MS(port, termios->c_cflag)) + pl011_enable_ms(port); + + if (port->rs485.flags & SER_RS485_ENABLED) + termios->c_cflag &= ~CRTSCTS; + + old_cr = pl011_read(uap, REG_CR); + + if (termios->c_cflag & CRTSCTS) { + if (old_cr & UART011_CR_RTS) + old_cr |= UART011_CR_RTSEN; + + old_cr |= UART011_CR_CTSEN; + port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS; + } else { + old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN); + port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS); + } + + if (uap->vendor->oversampling) { + if (baud > port->uartclk / 16) + old_cr |= ST_UART011_CR_OVSFACT; + else + old_cr &= ~ST_UART011_CR_OVSFACT; + } + + /* + * Workaround for the ST Micro oversampling variants to + * increase the bitrate slightly, by lowering the divisor, + * to avoid delayed sampling of start bit at high speeds, + * else we see data corruption. + */ + if (uap->vendor->oversampling) { + if ((baud >= 3000000) && (baud < 3250000) && (quot > 1)) + quot -= 1; + else if ((baud > 3250000) && (quot > 2)) + quot -= 2; + } + /* Set baud rate */ + pl011_write(quot & 0x3f, uap, REG_FBRD); + pl011_write(quot >> 6, uap, REG_IBRD); + + /* + * ----------v----------v----------v----------v----- + * NOTE: REG_LCRH_TX and REG_LCRH_RX MUST BE WRITTEN AFTER + * REG_FBRD & REG_IBRD. + * ----------^----------^----------^----------^----- + */ + pl011_write_lcr_h(uap, lcr_h); + pl011_write(old_cr, uap, REG_CR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +static void +sbsa_uart_set_termios(struct uart_port *port, struct ktermios *termios, + const struct ktermios *old) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + unsigned long flags; + + tty_termios_encode_baud_rate(termios, uap->fixed_baud, uap->fixed_baud); + + /* The SBSA UART only supports 8n1 without hardware flow control. */ + termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD); + termios->c_cflag &= ~(CMSPAR | CRTSCTS); + termios->c_cflag |= CS8 | CLOCAL; + + spin_lock_irqsave(&port->lock, flags); + uart_update_timeout(port, CS8, uap->fixed_baud); + pl011_setup_status_masks(port, termios); + spin_unlock_irqrestore(&port->lock, flags); +} + +static const char *pl011_type(struct uart_port *port) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + return uap->port.type == PORT_AMBA ? uap->type : NULL; +} + +/* + * Configure/autoconfigure the port. + */ +static void pl011_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE) + port->type = PORT_AMBA; +} + +/* + * verify the new serial_struct (for TIOCSSERIAL). + */ +static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser) +{ + int ret = 0; + if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA) + ret = -EINVAL; + if (ser->irq < 0 || ser->irq >= nr_irqs) + ret = -EINVAL; + if (ser->baud_base < 9600) + ret = -EINVAL; + if (port->mapbase != (unsigned long) ser->iomem_base) + ret = -EINVAL; + return ret; +} + +static int pl011_rs485_config(struct uart_port *port, struct ktermios *termios, + struct serial_rs485 *rs485) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + if (port->rs485.flags & SER_RS485_ENABLED) + pl011_rs485_tx_stop(uap); + + /* Make sure auto RTS is disabled */ + if (rs485->flags & SER_RS485_ENABLED) { + u32 cr = pl011_read(uap, REG_CR); + + cr &= ~UART011_CR_RTSEN; + pl011_write(cr, uap, REG_CR); + port->status &= ~UPSTAT_AUTORTS; + } + + return 0; +} + +static const struct uart_ops amba_pl011_pops = { + .tx_empty = pl011_tx_empty, + .set_mctrl = pl011_set_mctrl, + .get_mctrl = pl011_get_mctrl, + .stop_tx = pl011_stop_tx, + .start_tx = pl011_start_tx, + .stop_rx = pl011_stop_rx, + .throttle = pl011_throttle_rx, + .unthrottle = pl011_unthrottle_rx, + .enable_ms = pl011_enable_ms, + .break_ctl = pl011_break_ctl, + .startup = pl011_startup, + .shutdown = pl011_shutdown, + .flush_buffer = pl011_dma_flush_buffer, + .set_termios = pl011_set_termios, + .type = pl011_type, + .config_port = pl011_config_port, + .verify_port = pl011_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_init = pl011_hwinit, + .poll_get_char = pl011_get_poll_char, + .poll_put_char = pl011_put_poll_char, +#endif +}; + +static void sbsa_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ +} + +static unsigned int sbsa_uart_get_mctrl(struct uart_port *port) +{ + return 0; +} + +static const struct uart_ops sbsa_uart_pops = { + .tx_empty = pl011_tx_empty, + .set_mctrl = sbsa_uart_set_mctrl, + .get_mctrl = sbsa_uart_get_mctrl, + .stop_tx = pl011_stop_tx, + .start_tx = pl011_start_tx, + .stop_rx = pl011_stop_rx, + .startup = sbsa_uart_startup, + .shutdown = sbsa_uart_shutdown, + .set_termios = sbsa_uart_set_termios, + .type = pl011_type, + .config_port = pl011_config_port, + .verify_port = pl011_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_init = pl011_hwinit, + .poll_get_char = pl011_get_poll_char, + .poll_put_char = pl011_put_poll_char, +#endif +}; + +static struct uart_amba_port *amba_ports[UART_NR]; + +#ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE + +static void pl011_console_putchar(struct uart_port *port, unsigned char ch) +{ + struct uart_amba_port *uap = + container_of(port, struct uart_amba_port, port); + + while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) + cpu_relax(); + pl011_write(ch, uap, REG_DR); +} + +static void +pl011_console_write(struct console *co, const char *s, unsigned int count) +{ + struct uart_amba_port *uap = amba_ports[co->index]; + unsigned int old_cr = 0, new_cr; + unsigned long flags; + int locked = 1; + + clk_enable(uap->clk); + + local_irq_save(flags); + if (uap->port.sysrq) + locked = 0; + else if (oops_in_progress) + locked = spin_trylock(&uap->port.lock); + else + spin_lock(&uap->port.lock); + + /* + * First save the CR then disable the interrupts + */ + if (!uap->vendor->always_enabled) { + old_cr = pl011_read(uap, REG_CR); + new_cr = old_cr & ~UART011_CR_CTSEN; + new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE; + pl011_write(new_cr, uap, REG_CR); + } + + uart_console_write(&uap->port, s, count, pl011_console_putchar); + + /* + * Finally, wait for transmitter to become empty and restore the + * TCR. Allow feature register bits to be inverted to work around + * errata. + */ + while ((pl011_read(uap, REG_FR) ^ uap->vendor->inv_fr) + & uap->vendor->fr_busy) + cpu_relax(); + if (!uap->vendor->always_enabled) + pl011_write(old_cr, uap, REG_CR); + + if (locked) + spin_unlock(&uap->port.lock); + local_irq_restore(flags); + + clk_disable(uap->clk); +} + +static void pl011_console_get_options(struct uart_amba_port *uap, int *baud, + int *parity, int *bits) +{ + if (pl011_read(uap, REG_CR) & UART01x_CR_UARTEN) { + unsigned int lcr_h, ibrd, fbrd; + + lcr_h = pl011_read(uap, REG_LCRH_TX); + + *parity = 'n'; + if (lcr_h & UART01x_LCRH_PEN) { + if (lcr_h & UART01x_LCRH_EPS) + *parity = 'e'; + else + *parity = 'o'; + } + + if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7) + *bits = 7; + else + *bits = 8; + + ibrd = pl011_read(uap, REG_IBRD); + fbrd = pl011_read(uap, REG_FBRD); + + *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd); + + if (uap->vendor->oversampling) { + if (pl011_read(uap, REG_CR) + & ST_UART011_CR_OVSFACT) + *baud *= 2; + } + } +} + +static int pl011_console_setup(struct console *co, char *options) +{ + struct uart_amba_port *uap; + int baud = 38400; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + int ret; + + /* + * Check whether an invalid uart number has been specified, and + * if so, search for the first available port that does have + * console support. + */ + if (co->index >= UART_NR) + co->index = 0; + uap = amba_ports[co->index]; + if (!uap) + return -ENODEV; + + /* Allow pins to be muxed in and configured */ + pinctrl_pm_select_default_state(uap->port.dev); + + ret = clk_prepare(uap->clk); + if (ret) + return ret; + + if (dev_get_platdata(uap->port.dev)) { + struct amba_pl011_data *plat; + + plat = dev_get_platdata(uap->port.dev); + if (plat->init) + plat->init(); + } + + uap->port.uartclk = clk_get_rate(uap->clk); + + if (uap->vendor->fixed_options) { + baud = uap->fixed_baud; + } else { + if (options) + uart_parse_options(options, + &baud, &parity, &bits, &flow); + else + pl011_console_get_options(uap, &baud, &parity, &bits); + } + + return uart_set_options(&uap->port, co, baud, parity, bits, flow); +} + +/** + * pl011_console_match - non-standard console matching + * @co: registering console + * @name: name from console command line + * @idx: index from console command line + * @options: ptr to option string from console command line + * + * Only attempts to match console command lines of the form: + * console=pl011,mmio|mmio32,<addr>[,<options>] + * console=pl011,0x<addr>[,<options>] + * This form is used to register an initial earlycon boot console and + * replace it with the amba_console at pl011 driver init. + * + * Performs console setup for a match (as required by interface) + * If no <options> are specified, then assume the h/w is already setup. + * + * Returns 0 if console matches; otherwise non-zero to use default matching + */ +static int pl011_console_match(struct console *co, char *name, int idx, + char *options) +{ + unsigned char iotype; + resource_size_t addr; + int i; + + /* + * Systems affected by the Qualcomm Technologies QDF2400 E44 erratum + * have a distinct console name, so make sure we check for that. + * The actual implementation of the erratum occurs in the probe + * function. + */ + if ((strcmp(name, "qdf2400_e44") != 0) && (strcmp(name, "pl011") != 0)) + return -ENODEV; + + if (uart_parse_earlycon(options, &iotype, &addr, &options)) + return -ENODEV; + + if (iotype != UPIO_MEM && iotype != UPIO_MEM32) + return -ENODEV; + + /* try to match the port specified on the command line */ + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) { + struct uart_port *port; + + if (!amba_ports[i]) + continue; + + port = &amba_ports[i]->port; + + if (port->mapbase != addr) + continue; + + co->index = i; + port->cons = co; + return pl011_console_setup(co, options); + } + + return -ENODEV; +} + +static struct uart_driver amba_reg; +static struct console amba_console = { + .name = "ttyAMA", + .write = pl011_console_write, + .device = uart_console_device, + .setup = pl011_console_setup, + .match = pl011_console_match, + .flags = CON_PRINTBUFFER | CON_ANYTIME, + .index = -1, + .data = &amba_reg, +}; + +#define AMBA_CONSOLE (&amba_console) + +static void qdf2400_e44_putc(struct uart_port *port, unsigned char c) +{ + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) + cpu_relax(); + writel(c, port->membase + UART01x_DR); + while (!(readl(port->membase + UART01x_FR) & UART011_FR_TXFE)) + cpu_relax(); +} + +static void qdf2400_e44_early_write(struct console *con, const char *s, unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, qdf2400_e44_putc); +} + +static void pl011_putc(struct uart_port *port, unsigned char c) +{ + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) + cpu_relax(); + if (port->iotype == UPIO_MEM32) + writel(c, port->membase + UART01x_DR); + else + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) + cpu_relax(); +} + +static void pl011_early_write(struct console *con, const char *s, unsigned n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, pl011_putc); +} + +#ifdef CONFIG_CONSOLE_POLL +static int pl011_getc(struct uart_port *port) +{ + if (readl(port->membase + UART01x_FR) & UART01x_FR_RXFE) + return NO_POLL_CHAR; + + if (port->iotype == UPIO_MEM32) + return readl(port->membase + UART01x_DR); + else + return readb(port->membase + UART01x_DR); +} + +static int pl011_early_read(struct console *con, char *s, unsigned int n) +{ + struct earlycon_device *dev = con->data; + int ch, num_read = 0; + + while (num_read < n) { + ch = pl011_getc(&dev->port); + if (ch == NO_POLL_CHAR) + break; + + s[num_read++] = ch; + } + + return num_read; +} +#else +#define pl011_early_read NULL +#endif + +/* + * On non-ACPI systems, earlycon is enabled by specifying + * "earlycon=pl011,<address>" on the kernel command line. + * + * On ACPI ARM64 systems, an "early" console is enabled via the SPCR table, + * by specifying only "earlycon" on the command line. Because it requires + * SPCR, the console starts after ACPI is parsed, which is later than a + * traditional early console. + * + * To get the traditional early console that starts before ACPI is parsed, + * specify the full "earlycon=pl011,<address>" option. + */ +static int __init pl011_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = pl011_early_write; + device->con->read = pl011_early_read; + + return 0; +} +OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup); +OF_EARLYCON_DECLARE(pl011, "arm,sbsa-uart", pl011_early_console_setup); + +/* + * On Qualcomm Datacenter Technologies QDF2400 SOCs affected by + * Erratum 44, traditional earlycon can be enabled by specifying + * "earlycon=qdf2400_e44,<address>". Any options are ignored. + * + * Alternatively, you can just specify "earlycon", and the early console + * will be enabled with the information from the SPCR table. In this + * case, the SPCR code will detect the need for the E44 work-around, + * and set the console name to "qdf2400_e44". + */ +static int __init +qdf2400_e44_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + if (!device->port.membase) + return -ENODEV; + + device->con->write = qdf2400_e44_early_write; + return 0; +} +EARLYCON_DECLARE(qdf2400_e44, qdf2400_e44_early_console_setup); + +#else +#define AMBA_CONSOLE NULL +#endif + +static struct uart_driver amba_reg = { + .owner = THIS_MODULE, + .driver_name = "ttyAMA", + .dev_name = "ttyAMA", + .major = SERIAL_AMBA_MAJOR, + .minor = SERIAL_AMBA_MINOR, + .nr = UART_NR, + .cons = AMBA_CONSOLE, +}; + +static int pl011_probe_dt_alias(int index, struct device *dev) +{ + struct device_node *np; + static bool seen_dev_with_alias = false; + static bool seen_dev_without_alias = false; + int ret = index; + + if (!IS_ENABLED(CONFIG_OF)) + return ret; + + np = dev->of_node; + if (!np) + return ret; + + ret = of_alias_get_id(np, "serial"); + if (ret < 0) { + seen_dev_without_alias = true; + ret = index; + } else { + seen_dev_with_alias = true; + if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) { + dev_warn(dev, "requested serial port %d not available.\n", ret); + ret = index; + } + } + + if (seen_dev_with_alias && seen_dev_without_alias) + dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n"); + + return ret; +} + +/* unregisters the driver also if no more ports are left */ +static void pl011_unregister_port(struct uart_amba_port *uap) +{ + int i; + bool busy = false; + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) { + if (amba_ports[i] == uap) + amba_ports[i] = NULL; + else if (amba_ports[i]) + busy = true; + } + pl011_dma_remove(uap); + if (!busy) + uart_unregister_driver(&amba_reg); +} + +static int pl011_find_free_port(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == NULL) + return i; + + return -EBUSY; +} + +static int pl011_get_rs485_mode(struct uart_amba_port *uap) +{ + struct uart_port *port = &uap->port; + int ret; + + ret = uart_get_rs485_mode(port); + if (ret) + return ret; + + return 0; +} + +static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap, + struct resource *mmiobase, int index) +{ + void __iomem *base; + int ret; + + base = devm_ioremap_resource(dev, mmiobase); + if (IS_ERR(base)) + return PTR_ERR(base); + + index = pl011_probe_dt_alias(index, dev); + + uap->port.dev = dev; + uap->port.mapbase = mmiobase->start; + uap->port.membase = base; + uap->port.fifosize = uap->fifosize; + uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL011_CONSOLE); + uap->port.flags = UPF_BOOT_AUTOCONF; + uap->port.line = index; + + ret = pl011_get_rs485_mode(uap); + if (ret) + return ret; + + amba_ports[index] = uap; + + return 0; +} + +static int pl011_register_port(struct uart_amba_port *uap) +{ + int ret, i; + + /* Ensure interrupts from this UART are masked and cleared */ + pl011_write(0, uap, REG_IMSC); + pl011_write(0xffff, uap, REG_ICR); + + if (!amba_reg.state) { + ret = uart_register_driver(&amba_reg); + if (ret < 0) { + dev_err(uap->port.dev, + "Failed to register AMBA-PL011 driver\n"); + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) + if (amba_ports[i] == uap) + amba_ports[i] = NULL; + return ret; + } + } + + ret = uart_add_one_port(&amba_reg, &uap->port); + if (ret) + pl011_unregister_port(uap); + + return ret; +} + +static const struct serial_rs485 pl011_rs485_supported = { + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | + SER_RS485_RX_DURING_TX, + .delay_rts_before_send = 1, + .delay_rts_after_send = 1, +}; + +static int pl011_probe(struct amba_device *dev, const struct amba_id *id) +{ + struct uart_amba_port *uap; + struct vendor_data *vendor = id->data; + int portnr, ret; + u32 val; + + portnr = pl011_find_free_port(); + if (portnr < 0) + return portnr; + + uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port), + GFP_KERNEL); + if (!uap) + return -ENOMEM; + + uap->clk = devm_clk_get(&dev->dev, NULL); + if (IS_ERR(uap->clk)) + return PTR_ERR(uap->clk); + + uap->reg_offset = vendor->reg_offset; + uap->vendor = vendor; + uap->fifosize = vendor->get_fifosize(dev); + uap->port.iotype = vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; + uap->port.irq = dev->irq[0]; + uap->port.ops = &amba_pl011_pops; + uap->port.rs485_config = pl011_rs485_config; + uap->port.rs485_supported = pl011_rs485_supported; + snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev)); + + if (device_property_read_u32(&dev->dev, "reg-io-width", &val) == 0) { + switch (val) { + case 1: + uap->port.iotype = UPIO_MEM; + break; + case 4: + uap->port.iotype = UPIO_MEM32; + break; + default: + dev_warn(&dev->dev, "unsupported reg-io-width (%d)\n", + val); + return -EINVAL; + } + } + + ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr); + if (ret) + return ret; + + amba_set_drvdata(dev, uap); + + return pl011_register_port(uap); +} + +static void pl011_remove(struct amba_device *dev) +{ + struct uart_amba_port *uap = amba_get_drvdata(dev); + + uart_remove_one_port(&amba_reg, &uap->port); + pl011_unregister_port(uap); +} + +#ifdef CONFIG_PM_SLEEP +static int pl011_suspend(struct device *dev) +{ + struct uart_amba_port *uap = dev_get_drvdata(dev); + + if (!uap) + return -EINVAL; + + return uart_suspend_port(&amba_reg, &uap->port); +} + +static int pl011_resume(struct device *dev) +{ + struct uart_amba_port *uap = dev_get_drvdata(dev); + + if (!uap) + return -EINVAL; + + return uart_resume_port(&amba_reg, &uap->port); +} +#endif + +static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume); + +static int sbsa_uart_probe(struct platform_device *pdev) +{ + struct uart_amba_port *uap; + struct resource *r; + int portnr, ret; + int baudrate; + + /* + * Check the mandatory baud rate parameter in the DT node early + * so that we can easily exit with the error. + */ + if (pdev->dev.of_node) { + struct device_node *np = pdev->dev.of_node; + + ret = of_property_read_u32(np, "current-speed", &baudrate); + if (ret) + return ret; + } else { + baudrate = 115200; + } + + portnr = pl011_find_free_port(); + if (portnr < 0) + return portnr; + + uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port), + GFP_KERNEL); + if (!uap) + return -ENOMEM; + + ret = platform_get_irq(pdev, 0); + if (ret < 0) + return ret; + uap->port.irq = ret; + +#ifdef CONFIG_ACPI_SPCR_TABLE + if (qdf2400_e44_present) { + dev_info(&pdev->dev, "working around QDF2400 SoC erratum 44\n"); + uap->vendor = &vendor_qdt_qdf2400_e44; + } else +#endif + uap->vendor = &vendor_sbsa; + + uap->reg_offset = uap->vendor->reg_offset; + uap->fifosize = 32; + uap->port.iotype = uap->vendor->access_32b ? UPIO_MEM32 : UPIO_MEM; + uap->port.ops = &sbsa_uart_pops; + uap->fixed_baud = baudrate; + + snprintf(uap->type, sizeof(uap->type), "SBSA"); + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + ret = pl011_setup_port(&pdev->dev, uap, r, portnr); + if (ret) + return ret; + + platform_set_drvdata(pdev, uap); + + return pl011_register_port(uap); +} + +static int sbsa_uart_remove(struct platform_device *pdev) +{ + struct uart_amba_port *uap = platform_get_drvdata(pdev); + + uart_remove_one_port(&amba_reg, &uap->port); + pl011_unregister_port(uap); + return 0; +} + +static const struct of_device_id sbsa_uart_of_match[] = { + { .compatible = "arm,sbsa-uart", }, + {}, +}; +MODULE_DEVICE_TABLE(of, sbsa_uart_of_match); + +static const struct acpi_device_id __maybe_unused sbsa_uart_acpi_match[] = { + { "ARMH0011", 0 }, + { "ARMHB000", 0 }, + {}, +}; +MODULE_DEVICE_TABLE(acpi, sbsa_uart_acpi_match); + +static struct platform_driver arm_sbsa_uart_platform_driver = { + .probe = sbsa_uart_probe, + .remove = sbsa_uart_remove, + .driver = { + .name = "sbsa-uart", + .pm = &pl011_dev_pm_ops, + .of_match_table = of_match_ptr(sbsa_uart_of_match), + .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match), + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), + }, +}; + +static const struct amba_id pl011_ids[] = { + { + .id = 0x00041011, + .mask = 0x000fffff, + .data = &vendor_arm, + }, + { + .id = 0x00380802, + .mask = 0x00ffffff, + .data = &vendor_st, + }, + { 0, 0 }, +}; + +MODULE_DEVICE_TABLE(amba, pl011_ids); + +static struct amba_driver pl011_driver = { + .drv = { + .name = "uart-pl011", + .pm = &pl011_dev_pm_ops, + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_AMBA_PL011), + }, + .id_table = pl011_ids, + .probe = pl011_probe, + .remove = pl011_remove, +}; + +static int __init pl011_init(void) +{ + printk(KERN_INFO "Serial: AMBA PL011 UART driver\n"); + + if (platform_driver_register(&arm_sbsa_uart_platform_driver)) + pr_warn("could not register SBSA UART platform driver\n"); + return amba_driver_register(&pl011_driver); +} + +static void __exit pl011_exit(void) +{ + platform_driver_unregister(&arm_sbsa_uart_platform_driver); + amba_driver_unregister(&pl011_driver); +} + +/* + * While this can be a module, if builtin it's most likely the console + * So let's leave module_exit but move module_init to an earlier place + */ +arch_initcall(pl011_init); +module_exit(pl011_exit); + +MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd"); +MODULE_DESCRIPTION("ARM AMBA serial port driver"); +MODULE_LICENSE("GPL"); |