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-rw-r--r--drivers/tty/serial/serial-tegra.c1720
1 files changed, 1720 insertions, 0 deletions
diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c
new file mode 100644
index 000000000..fac4d9004
--- /dev/null
+++ b/drivers/tty/serial/serial-tegra.c
@@ -0,0 +1,1720 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * serial_tegra.c
+ *
+ * High-speed serial driver for NVIDIA Tegra SoCs
+ *
+ * Copyright (c) 2012-2019, NVIDIA CORPORATION. All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pagemap.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/termios.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+
+#define TEGRA_UART_TYPE "TEGRA_UART"
+#define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
+#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
+
+#define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
+#define TEGRA_UART_LSR_TXFIFO_FULL 0x100
+#define TEGRA_UART_IER_EORD 0x20
+#define TEGRA_UART_MCR_RTS_EN 0x40
+#define TEGRA_UART_MCR_CTS_EN 0x20
+#define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
+ UART_LSR_PE | UART_LSR_FE)
+#define TEGRA_UART_IRDA_CSR 0x08
+#define TEGRA_UART_SIR_ENABLED 0x80
+
+#define TEGRA_UART_TX_PIO 1
+#define TEGRA_UART_TX_DMA 2
+#define TEGRA_UART_MIN_DMA 16
+#define TEGRA_UART_FIFO_SIZE 32
+
+/*
+ * Tx fifo trigger level setting in tegra uart is in
+ * reverse way then conventional uart.
+ */
+#define TEGRA_UART_TX_TRIG_16B 0x00
+#define TEGRA_UART_TX_TRIG_8B 0x10
+#define TEGRA_UART_TX_TRIG_4B 0x20
+#define TEGRA_UART_TX_TRIG_1B 0x30
+
+#define TEGRA_UART_MAXIMUM 8
+
+/* Default UART setting when started: 115200 no parity, stop, 8 data bits */
+#define TEGRA_UART_DEFAULT_BAUD 115200
+#define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
+
+/* Tx transfer mode */
+#define TEGRA_TX_PIO 1
+#define TEGRA_TX_DMA 2
+
+#define TEGRA_UART_FCR_IIR_FIFO_EN 0x40
+
+/**
+ * tegra_uart_chip_data: SOC specific data.
+ *
+ * @tx_fifo_full_status: Status flag available for checking tx fifo full.
+ * @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
+ * Tegra30 does not allow this.
+ * @support_clk_src_div: Clock source support the clock divider.
+ */
+struct tegra_uart_chip_data {
+ bool tx_fifo_full_status;
+ bool allow_txfifo_reset_fifo_mode;
+ bool support_clk_src_div;
+ bool fifo_mode_enable_status;
+ int uart_max_port;
+ int max_dma_burst_bytes;
+ int error_tolerance_low_range;
+ int error_tolerance_high_range;
+};
+
+struct tegra_baud_tolerance {
+ u32 lower_range_baud;
+ u32 upper_range_baud;
+ s32 tolerance;
+};
+
+struct tegra_uart_port {
+ struct uart_port uport;
+ const struct tegra_uart_chip_data *cdata;
+
+ struct clk *uart_clk;
+ struct reset_control *rst;
+ unsigned int current_baud;
+
+ /* Register shadow */
+ unsigned long fcr_shadow;
+ unsigned long mcr_shadow;
+ unsigned long lcr_shadow;
+ unsigned long ier_shadow;
+ bool rts_active;
+
+ int tx_in_progress;
+ unsigned int tx_bytes;
+
+ bool enable_modem_interrupt;
+
+ bool rx_timeout;
+ int rx_in_progress;
+ int symb_bit;
+
+ struct dma_chan *rx_dma_chan;
+ struct dma_chan *tx_dma_chan;
+ dma_addr_t rx_dma_buf_phys;
+ dma_addr_t tx_dma_buf_phys;
+ unsigned char *rx_dma_buf_virt;
+ unsigned char *tx_dma_buf_virt;
+ struct dma_async_tx_descriptor *tx_dma_desc;
+ struct dma_async_tx_descriptor *rx_dma_desc;
+ dma_cookie_t tx_cookie;
+ dma_cookie_t rx_cookie;
+ unsigned int tx_bytes_requested;
+ unsigned int rx_bytes_requested;
+ struct tegra_baud_tolerance *baud_tolerance;
+ int n_adjustable_baud_rates;
+ int required_rate;
+ int configured_rate;
+ bool use_rx_pio;
+ bool use_tx_pio;
+ bool rx_dma_active;
+};
+
+static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
+static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
+static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
+ bool dma_to_memory);
+
+static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
+ unsigned long reg)
+{
+ return readl(tup->uport.membase + (reg << tup->uport.regshift));
+}
+
+static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
+ unsigned long reg)
+{
+ writel(val, tup->uport.membase + (reg << tup->uport.regshift));
+}
+
+static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
+{
+ return container_of(u, struct tegra_uart_port, uport);
+}
+
+static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+
+ /*
+ * RI - Ring detector is active
+ * CD/DCD/CAR - Carrier detect is always active. For some reason
+ * linux has different names for carrier detect.
+ * DSR - Data Set ready is active as the hardware doesn't support it.
+ * Don't know if the linux support this yet?
+ * CTS - Clear to send. Always set to active, as the hardware handles
+ * CTS automatically.
+ */
+ if (tup->enable_modem_interrupt)
+ return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
+ return TIOCM_CTS;
+}
+
+static void set_rts(struct tegra_uart_port *tup, bool active)
+{
+ unsigned long mcr;
+
+ mcr = tup->mcr_shadow;
+ if (active)
+ mcr |= TEGRA_UART_MCR_RTS_EN;
+ else
+ mcr &= ~TEGRA_UART_MCR_RTS_EN;
+ if (mcr != tup->mcr_shadow) {
+ tegra_uart_write(tup, mcr, UART_MCR);
+ tup->mcr_shadow = mcr;
+ }
+}
+
+static void set_dtr(struct tegra_uart_port *tup, bool active)
+{
+ unsigned long mcr;
+
+ mcr = tup->mcr_shadow;
+ if (active)
+ mcr |= UART_MCR_DTR;
+ else
+ mcr &= ~UART_MCR_DTR;
+ if (mcr != tup->mcr_shadow) {
+ tegra_uart_write(tup, mcr, UART_MCR);
+ tup->mcr_shadow = mcr;
+ }
+}
+
+static void set_loopbk(struct tegra_uart_port *tup, bool active)
+{
+ unsigned long mcr = tup->mcr_shadow;
+
+ if (active)
+ mcr |= UART_MCR_LOOP;
+ else
+ mcr &= ~UART_MCR_LOOP;
+
+ if (mcr != tup->mcr_shadow) {
+ tegra_uart_write(tup, mcr, UART_MCR);
+ tup->mcr_shadow = mcr;
+ }
+}
+
+static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ int enable;
+
+ tup->rts_active = !!(mctrl & TIOCM_RTS);
+ set_rts(tup, tup->rts_active);
+
+ enable = !!(mctrl & TIOCM_DTR);
+ set_dtr(tup, enable);
+
+ enable = !!(mctrl & TIOCM_LOOP);
+ set_loopbk(tup, enable);
+}
+
+static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ unsigned long lcr;
+
+ lcr = tup->lcr_shadow;
+ if (break_ctl)
+ lcr |= UART_LCR_SBC;
+ else
+ lcr &= ~UART_LCR_SBC;
+ tegra_uart_write(tup, lcr, UART_LCR);
+ tup->lcr_shadow = lcr;
+}
+
+/**
+ * tegra_uart_wait_cycle_time: Wait for N UART clock periods
+ *
+ * @tup: Tegra serial port data structure.
+ * @cycles: Number of clock periods to wait.
+ *
+ * Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART
+ * clock speed is 16X the current baud rate.
+ */
+static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup,
+ unsigned int cycles)
+{
+ if (tup->current_baud)
+ udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16));
+}
+
+/* Wait for a symbol-time. */
+static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
+ unsigned int syms)
+{
+ if (tup->current_baud)
+ udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
+ tup->current_baud));
+}
+
+static int tegra_uart_wait_fifo_mode_enabled(struct tegra_uart_port *tup)
+{
+ unsigned long iir;
+ unsigned int tmout = 100;
+
+ do {
+ iir = tegra_uart_read(tup, UART_IIR);
+ if (iir & TEGRA_UART_FCR_IIR_FIFO_EN)
+ return 0;
+ udelay(1);
+ } while (--tmout);
+
+ return -ETIMEDOUT;
+}
+
+static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
+{
+ unsigned long fcr = tup->fcr_shadow;
+ unsigned int lsr, tmout = 10000;
+
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ if (tup->cdata->allow_txfifo_reset_fifo_mode) {
+ fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+ tegra_uart_write(tup, fcr, UART_FCR);
+ } else {
+ fcr &= ~UART_FCR_ENABLE_FIFO;
+ tegra_uart_write(tup, fcr, UART_FCR);
+ udelay(60);
+ fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+ tegra_uart_write(tup, fcr, UART_FCR);
+ fcr |= UART_FCR_ENABLE_FIFO;
+ tegra_uart_write(tup, fcr, UART_FCR);
+ if (tup->cdata->fifo_mode_enable_status)
+ tegra_uart_wait_fifo_mode_enabled(tup);
+ }
+
+ /* Dummy read to ensure the write is posted */
+ tegra_uart_read(tup, UART_SCR);
+
+ /*
+ * For all tegra devices (up to t210), there is a hardware issue that
+ * requires software to wait for 32 UART clock periods for the flush
+ * to propagate, otherwise data could be lost.
+ */
+ tegra_uart_wait_cycle_time(tup, 32);
+
+ do {
+ lsr = tegra_uart_read(tup, UART_LSR);
+ if ((lsr & UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
+ break;
+ udelay(1);
+ } while (--tmout);
+
+ if (tup->rts_active)
+ set_rts(tup, true);
+}
+
+static long tegra_get_tolerance_rate(struct tegra_uart_port *tup,
+ unsigned int baud, long rate)
+{
+ int i;
+
+ for (i = 0; i < tup->n_adjustable_baud_rates; ++i) {
+ if (baud >= tup->baud_tolerance[i].lower_range_baud &&
+ baud <= tup->baud_tolerance[i].upper_range_baud)
+ return (rate + (rate *
+ tup->baud_tolerance[i].tolerance) / 10000);
+ }
+
+ return rate;
+}
+
+static int tegra_check_rate_in_range(struct tegra_uart_port *tup)
+{
+ long diff;
+
+ diff = ((long)(tup->configured_rate - tup->required_rate) * 10000)
+ / tup->required_rate;
+ if (diff < (tup->cdata->error_tolerance_low_range * 100) ||
+ diff > (tup->cdata->error_tolerance_high_range * 100)) {
+ dev_err(tup->uport.dev,
+ "configured baud rate is out of range by %ld", diff);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
+{
+ unsigned long rate;
+ unsigned int divisor;
+ unsigned long lcr;
+ unsigned long flags;
+ int ret;
+
+ if (tup->current_baud == baud)
+ return 0;
+
+ if (tup->cdata->support_clk_src_div) {
+ rate = baud * 16;
+ tup->required_rate = rate;
+
+ if (tup->n_adjustable_baud_rates)
+ rate = tegra_get_tolerance_rate(tup, baud, rate);
+
+ ret = clk_set_rate(tup->uart_clk, rate);
+ if (ret < 0) {
+ dev_err(tup->uport.dev,
+ "clk_set_rate() failed for rate %lu\n", rate);
+ return ret;
+ }
+ tup->configured_rate = clk_get_rate(tup->uart_clk);
+ divisor = 1;
+ ret = tegra_check_rate_in_range(tup);
+ if (ret < 0)
+ return ret;
+ } else {
+ rate = clk_get_rate(tup->uart_clk);
+ divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
+ }
+
+ spin_lock_irqsave(&tup->uport.lock, flags);
+ lcr = tup->lcr_shadow;
+ lcr |= UART_LCR_DLAB;
+ tegra_uart_write(tup, lcr, UART_LCR);
+
+ tegra_uart_write(tup, divisor & 0xFF, UART_TX);
+ tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
+
+ lcr &= ~UART_LCR_DLAB;
+ tegra_uart_write(tup, lcr, UART_LCR);
+
+ /* Dummy read to ensure the write is posted */
+ tegra_uart_read(tup, UART_SCR);
+ spin_unlock_irqrestore(&tup->uport.lock, flags);
+
+ tup->current_baud = baud;
+
+ /* wait two character intervals at new rate */
+ tegra_uart_wait_sym_time(tup, 2);
+ return 0;
+}
+
+static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
+ unsigned long lsr)
+{
+ char flag = TTY_NORMAL;
+
+ if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
+ if (lsr & UART_LSR_OE) {
+ /* Overrrun error */
+ flag = TTY_OVERRUN;
+ tup->uport.icount.overrun++;
+ dev_dbg(tup->uport.dev, "Got overrun errors\n");
+ } else if (lsr & UART_LSR_PE) {
+ /* Parity error */
+ flag = TTY_PARITY;
+ tup->uport.icount.parity++;
+ dev_dbg(tup->uport.dev, "Got Parity errors\n");
+ } else if (lsr & UART_LSR_FE) {
+ flag = TTY_FRAME;
+ tup->uport.icount.frame++;
+ dev_dbg(tup->uport.dev, "Got frame errors\n");
+ } else if (lsr & UART_LSR_BI) {
+ /*
+ * Break error
+ * If FIFO read error without any data, reset Rx FIFO
+ */
+ if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
+ tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
+ if (tup->uport.ignore_status_mask & UART_LSR_BI)
+ return TTY_BREAK;
+ flag = TTY_BREAK;
+ tup->uport.icount.brk++;
+ dev_dbg(tup->uport.dev, "Got Break\n");
+ }
+ uart_insert_char(&tup->uport, lsr, UART_LSR_OE, 0, flag);
+ }
+
+ return flag;
+}
+
+static int tegra_uart_request_port(struct uart_port *u)
+{
+ return 0;
+}
+
+static void tegra_uart_release_port(struct uart_port *u)
+{
+ /* Nothing to do here */
+}
+
+static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
+{
+ struct circ_buf *xmit = &tup->uport.state->xmit;
+ int i;
+
+ for (i = 0; i < max_bytes; i++) {
+ BUG_ON(uart_circ_empty(xmit));
+ if (tup->cdata->tx_fifo_full_status) {
+ unsigned long lsr = tegra_uart_read(tup, UART_LSR);
+ if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
+ break;
+ }
+ tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ tup->uport.icount.tx++;
+ }
+}
+
+static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
+ unsigned int bytes)
+{
+ if (bytes > TEGRA_UART_MIN_DMA)
+ bytes = TEGRA_UART_MIN_DMA;
+
+ tup->tx_in_progress = TEGRA_UART_TX_PIO;
+ tup->tx_bytes = bytes;
+ tup->ier_shadow |= UART_IER_THRI;
+ tegra_uart_write(tup, tup->ier_shadow, UART_IER);
+}
+
+static void tegra_uart_tx_dma_complete(void *args)
+{
+ struct tegra_uart_port *tup = args;
+ struct circ_buf *xmit = &tup->uport.state->xmit;
+ struct dma_tx_state state;
+ unsigned long flags;
+ unsigned int count;
+
+ dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
+ count = tup->tx_bytes_requested - state.residue;
+ async_tx_ack(tup->tx_dma_desc);
+ spin_lock_irqsave(&tup->uport.lock, flags);
+ uart_xmit_advance(&tup->uport, count);
+ tup->tx_in_progress = 0;
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&tup->uport);
+ tegra_uart_start_next_tx(tup);
+ spin_unlock_irqrestore(&tup->uport.lock, flags);
+}
+
+static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
+ unsigned long count)
+{
+ struct circ_buf *xmit = &tup->uport.state->xmit;
+ dma_addr_t tx_phys_addr;
+
+ tup->tx_bytes = count & ~(0xF);
+ tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
+
+ dma_sync_single_for_device(tup->uport.dev, tx_phys_addr,
+ tup->tx_bytes, DMA_TO_DEVICE);
+
+ tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
+ tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
+ DMA_PREP_INTERRUPT);
+ if (!tup->tx_dma_desc) {
+ dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
+ return -EIO;
+ }
+
+ tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
+ tup->tx_dma_desc->callback_param = tup;
+ tup->tx_in_progress = TEGRA_UART_TX_DMA;
+ tup->tx_bytes_requested = tup->tx_bytes;
+ tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
+ dma_async_issue_pending(tup->tx_dma_chan);
+ return 0;
+}
+
+static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
+{
+ unsigned long tail;
+ unsigned long count;
+ struct circ_buf *xmit = &tup->uport.state->xmit;
+
+ if (!tup->current_baud)
+ return;
+
+ tail = (unsigned long)&xmit->buf[xmit->tail];
+ count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+ if (!count)
+ return;
+
+ if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA)
+ tegra_uart_start_pio_tx(tup, count);
+ else if (BYTES_TO_ALIGN(tail) > 0)
+ tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
+ else
+ tegra_uart_start_tx_dma(tup, count);
+}
+
+/* Called by serial core driver with u->lock taken. */
+static void tegra_uart_start_tx(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ struct circ_buf *xmit = &u->state->xmit;
+
+ if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
+ tegra_uart_start_next_tx(tup);
+}
+
+static unsigned int tegra_uart_tx_empty(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ unsigned int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&u->lock, flags);
+ if (!tup->tx_in_progress) {
+ unsigned long lsr = tegra_uart_read(tup, UART_LSR);
+ if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
+ ret = TIOCSER_TEMT;
+ }
+ spin_unlock_irqrestore(&u->lock, flags);
+ return ret;
+}
+
+static void tegra_uart_stop_tx(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ struct dma_tx_state state;
+ unsigned int count;
+
+ if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
+ return;
+
+ dmaengine_pause(tup->tx_dma_chan);
+ dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
+ dmaengine_terminate_all(tup->tx_dma_chan);
+ count = tup->tx_bytes_requested - state.residue;
+ async_tx_ack(tup->tx_dma_desc);
+ uart_xmit_advance(&tup->uport, count);
+ tup->tx_in_progress = 0;
+}
+
+static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
+{
+ struct circ_buf *xmit = &tup->uport.state->xmit;
+
+ tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
+ tup->tx_in_progress = 0;
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(&tup->uport);
+ tegra_uart_start_next_tx(tup);
+}
+
+static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
+ struct tty_port *port)
+{
+ do {
+ char flag = TTY_NORMAL;
+ unsigned long lsr = 0;
+ unsigned char ch;
+
+ lsr = tegra_uart_read(tup, UART_LSR);
+ if (!(lsr & UART_LSR_DR))
+ break;
+
+ flag = tegra_uart_decode_rx_error(tup, lsr);
+ if (flag != TTY_NORMAL)
+ continue;
+
+ ch = (unsigned char) tegra_uart_read(tup, UART_RX);
+ tup->uport.icount.rx++;
+
+ if (uart_handle_sysrq_char(&tup->uport, ch))
+ continue;
+
+ if (tup->uport.ignore_status_mask & UART_LSR_DR)
+ continue;
+
+ tty_insert_flip_char(port, ch, flag);
+ } while (1);
+}
+
+static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
+ struct tty_port *port,
+ unsigned int count)
+{
+ int copied;
+
+ /* If count is zero, then there is no data to be copied */
+ if (!count)
+ return;
+
+ tup->uport.icount.rx += count;
+
+ if (tup->uport.ignore_status_mask & UART_LSR_DR)
+ return;
+
+ dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
+ count, DMA_FROM_DEVICE);
+ copied = tty_insert_flip_string(port,
+ ((unsigned char *)(tup->rx_dma_buf_virt)), count);
+ if (copied != count) {
+ WARN_ON(1);
+ dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
+ }
+ dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
+ count, DMA_TO_DEVICE);
+}
+
+static void do_handle_rx_pio(struct tegra_uart_port *tup)
+{
+ struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
+ struct tty_port *port = &tup->uport.state->port;
+
+ tegra_uart_handle_rx_pio(tup, port);
+ if (tty) {
+ tty_flip_buffer_push(port);
+ tty_kref_put(tty);
+ }
+}
+
+static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
+ unsigned int residue)
+{
+ struct tty_port *port = &tup->uport.state->port;
+ unsigned int count;
+
+ async_tx_ack(tup->rx_dma_desc);
+ count = tup->rx_bytes_requested - residue;
+
+ /* If we are here, DMA is stopped */
+ tegra_uart_copy_rx_to_tty(tup, port, count);
+
+ do_handle_rx_pio(tup);
+}
+
+static void tegra_uart_rx_dma_complete(void *args)
+{
+ struct tegra_uart_port *tup = args;
+ struct uart_port *u = &tup->uport;
+ unsigned long flags;
+ struct dma_tx_state state;
+ enum dma_status status;
+
+ spin_lock_irqsave(&u->lock, flags);
+
+ status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
+
+ if (status == DMA_IN_PROGRESS) {
+ dev_dbg(tup->uport.dev, "RX DMA is in progress\n");
+ goto done;
+ }
+
+ /* Deactivate flow control to stop sender */
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ tup->rx_dma_active = false;
+ tegra_uart_rx_buffer_push(tup, 0);
+ tegra_uart_start_rx_dma(tup);
+
+ /* Activate flow control to start transfer */
+ if (tup->rts_active)
+ set_rts(tup, true);
+
+done:
+ spin_unlock_irqrestore(&u->lock, flags);
+}
+
+static void tegra_uart_terminate_rx_dma(struct tegra_uart_port *tup)
+{
+ struct dma_tx_state state;
+
+ if (!tup->rx_dma_active) {
+ do_handle_rx_pio(tup);
+ return;
+ }
+
+ dmaengine_pause(tup->rx_dma_chan);
+ dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
+ dmaengine_terminate_all(tup->rx_dma_chan);
+
+ tegra_uart_rx_buffer_push(tup, state.residue);
+ tup->rx_dma_active = false;
+}
+
+static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
+{
+ /* Deactivate flow control to stop sender */
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ tegra_uart_terminate_rx_dma(tup);
+
+ if (tup->rts_active)
+ set_rts(tup, true);
+}
+
+static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
+{
+ unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
+
+ if (tup->rx_dma_active)
+ return 0;
+
+ tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
+ tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
+ DMA_PREP_INTERRUPT);
+ if (!tup->rx_dma_desc) {
+ dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
+ return -EIO;
+ }
+
+ tup->rx_dma_active = true;
+ tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
+ tup->rx_dma_desc->callback_param = tup;
+ tup->rx_bytes_requested = count;
+ tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
+ dma_async_issue_pending(tup->rx_dma_chan);
+ return 0;
+}
+
+static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ unsigned long msr;
+
+ msr = tegra_uart_read(tup, UART_MSR);
+ if (!(msr & UART_MSR_ANY_DELTA))
+ return;
+
+ if (msr & UART_MSR_TERI)
+ tup->uport.icount.rng++;
+ if (msr & UART_MSR_DDSR)
+ tup->uport.icount.dsr++;
+ /* We may only get DDCD when HW init and reset */
+ if (msr & UART_MSR_DDCD)
+ uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
+ /* Will start/stop_tx accordingly */
+ if (msr & UART_MSR_DCTS)
+ uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
+}
+
+static irqreturn_t tegra_uart_isr(int irq, void *data)
+{
+ struct tegra_uart_port *tup = data;
+ struct uart_port *u = &tup->uport;
+ unsigned long iir;
+ unsigned long ier;
+ bool is_rx_start = false;
+ bool is_rx_int = false;
+ unsigned long flags;
+
+ spin_lock_irqsave(&u->lock, flags);
+ while (1) {
+ iir = tegra_uart_read(tup, UART_IIR);
+ if (iir & UART_IIR_NO_INT) {
+ if (!tup->use_rx_pio && is_rx_int) {
+ tegra_uart_handle_rx_dma(tup);
+ if (tup->rx_in_progress) {
+ ier = tup->ier_shadow;
+ ier |= (UART_IER_RLSI | UART_IER_RTOIE |
+ TEGRA_UART_IER_EORD | UART_IER_RDI);
+ tup->ier_shadow = ier;
+ tegra_uart_write(tup, ier, UART_IER);
+ }
+ } else if (is_rx_start) {
+ tegra_uart_start_rx_dma(tup);
+ }
+ spin_unlock_irqrestore(&u->lock, flags);
+ return IRQ_HANDLED;
+ }
+
+ switch ((iir >> 1) & 0x7) {
+ case 0: /* Modem signal change interrupt */
+ tegra_uart_handle_modem_signal_change(u);
+ break;
+
+ case 1: /* Transmit interrupt only triggered when using PIO */
+ tup->ier_shadow &= ~UART_IER_THRI;
+ tegra_uart_write(tup, tup->ier_shadow, UART_IER);
+ tegra_uart_handle_tx_pio(tup);
+ break;
+
+ case 4: /* End of data */
+ case 6: /* Rx timeout */
+ if (!tup->use_rx_pio) {
+ is_rx_int = tup->rx_in_progress;
+ /* Disable Rx interrupts */
+ ier = tup->ier_shadow;
+ ier &= ~(UART_IER_RDI | UART_IER_RLSI |
+ UART_IER_RTOIE | TEGRA_UART_IER_EORD);
+ tup->ier_shadow = ier;
+ tegra_uart_write(tup, ier, UART_IER);
+ break;
+ }
+ fallthrough;
+ case 2: /* Receive */
+ if (!tup->use_rx_pio) {
+ is_rx_start = tup->rx_in_progress;
+ tup->ier_shadow &= ~UART_IER_RDI;
+ tegra_uart_write(tup, tup->ier_shadow,
+ UART_IER);
+ } else {
+ do_handle_rx_pio(tup);
+ }
+ break;
+
+ case 3: /* Receive error */
+ tegra_uart_decode_rx_error(tup,
+ tegra_uart_read(tup, UART_LSR));
+ break;
+
+ case 5: /* break nothing to handle */
+ case 7: /* break nothing to handle */
+ break;
+ }
+ }
+}
+
+static void tegra_uart_stop_rx(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ struct tty_port *port = &tup->uport.state->port;
+ unsigned long ier;
+
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ if (!tup->rx_in_progress)
+ return;
+
+ tegra_uart_wait_sym_time(tup, 1); /* wait one character interval */
+
+ ier = tup->ier_shadow;
+ ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
+ TEGRA_UART_IER_EORD);
+ tup->ier_shadow = ier;
+ tegra_uart_write(tup, ier, UART_IER);
+ tup->rx_in_progress = 0;
+
+ if (!tup->use_rx_pio)
+ tegra_uart_terminate_rx_dma(tup);
+ else
+ tegra_uart_handle_rx_pio(tup, port);
+}
+
+static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
+{
+ unsigned long flags;
+ unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
+ unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
+ unsigned long wait_time;
+ unsigned long lsr;
+ unsigned long msr;
+ unsigned long mcr;
+
+ /* Disable interrupts */
+ tegra_uart_write(tup, 0, UART_IER);
+
+ lsr = tegra_uart_read(tup, UART_LSR);
+ if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
+ msr = tegra_uart_read(tup, UART_MSR);
+ mcr = tegra_uart_read(tup, UART_MCR);
+ if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
+ dev_err(tup->uport.dev,
+ "Tx Fifo not empty, CTS disabled, waiting\n");
+
+ /* Wait for Tx fifo to be empty */
+ while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
+ wait_time = min(fifo_empty_time, 100lu);
+ udelay(wait_time);
+ fifo_empty_time -= wait_time;
+ if (!fifo_empty_time) {
+ msr = tegra_uart_read(tup, UART_MSR);
+ mcr = tegra_uart_read(tup, UART_MCR);
+ if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
+ (msr & UART_MSR_CTS))
+ dev_err(tup->uport.dev,
+ "Slave not ready\n");
+ break;
+ }
+ lsr = tegra_uart_read(tup, UART_LSR);
+ }
+ }
+
+ spin_lock_irqsave(&tup->uport.lock, flags);
+ /* Reset the Rx and Tx FIFOs */
+ tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
+ tup->current_baud = 0;
+ spin_unlock_irqrestore(&tup->uport.lock, flags);
+
+ tup->rx_in_progress = 0;
+ tup->tx_in_progress = 0;
+
+ if (!tup->use_rx_pio)
+ tegra_uart_dma_channel_free(tup, true);
+ if (!tup->use_tx_pio)
+ tegra_uart_dma_channel_free(tup, false);
+
+ clk_disable_unprepare(tup->uart_clk);
+}
+
+static int tegra_uart_hw_init(struct tegra_uart_port *tup)
+{
+ int ret;
+
+ tup->fcr_shadow = 0;
+ tup->mcr_shadow = 0;
+ tup->lcr_shadow = 0;
+ tup->ier_shadow = 0;
+ tup->current_baud = 0;
+
+ ret = clk_prepare_enable(tup->uart_clk);
+ if (ret) {
+ dev_err(tup->uport.dev, "could not enable clk\n");
+ return ret;
+ }
+
+ /* Reset the UART controller to clear all previous status.*/
+ reset_control_assert(tup->rst);
+ udelay(10);
+ reset_control_deassert(tup->rst);
+
+ tup->rx_in_progress = 0;
+ tup->tx_in_progress = 0;
+
+ /*
+ * Set the trigger level
+ *
+ * For PIO mode:
+ *
+ * For receive, this will interrupt the CPU after that many number of
+ * bytes are received, for the remaining bytes the receive timeout
+ * interrupt is received. Rx high watermark is set to 4.
+ *
+ * For transmit, if the trasnmit interrupt is enabled, this will
+ * interrupt the CPU when the number of entries in the FIFO reaches the
+ * low watermark. Tx low watermark is set to 16 bytes.
+ *
+ * For DMA mode:
+ *
+ * Set the Tx trigger to 16. This should match the DMA burst size that
+ * programmed in the DMA registers.
+ */
+ tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
+
+ if (tup->use_rx_pio) {
+ tup->fcr_shadow |= UART_FCR_R_TRIG_11;
+ } else {
+ if (tup->cdata->max_dma_burst_bytes == 8)
+ tup->fcr_shadow |= UART_FCR_R_TRIG_10;
+ else
+ tup->fcr_shadow |= UART_FCR_R_TRIG_01;
+ }
+
+ tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
+ tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
+
+ /* Dummy read to ensure the write is posted */
+ tegra_uart_read(tup, UART_SCR);
+
+ if (tup->cdata->fifo_mode_enable_status) {
+ ret = tegra_uart_wait_fifo_mode_enabled(tup);
+ if (ret < 0) {
+ dev_err(tup->uport.dev,
+ "Failed to enable FIFO mode: %d\n", ret);
+ return ret;
+ }
+ } else {
+ /*
+ * For all tegra devices (up to t210), there is a hardware
+ * issue that requires software to wait for 3 UART clock
+ * periods after enabling the TX fifo, otherwise data could
+ * be lost.
+ */
+ tegra_uart_wait_cycle_time(tup, 3);
+ }
+
+ /*
+ * Initialize the UART with default configuration
+ * (115200, N, 8, 1) so that the receive DMA buffer may be
+ * enqueued
+ */
+ ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
+ if (ret < 0) {
+ dev_err(tup->uport.dev, "Failed to set baud rate\n");
+ return ret;
+ }
+ if (!tup->use_rx_pio) {
+ tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
+ tup->fcr_shadow |= UART_FCR_DMA_SELECT;
+ tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
+ } else {
+ tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
+ }
+ tup->rx_in_progress = 1;
+
+ /*
+ * Enable IE_RXS for the receive status interrupts like line errros.
+ * Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
+ *
+ * EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
+ * the DATA is sitting in the FIFO and couldn't be transferred to the
+ * DMA as the DMA size alignment (4 bytes) is not met. EORD will be
+ * triggered when there is a pause of the incomming data stream for 4
+ * characters long.
+ *
+ * For pauses in the data which is not aligned to 4 bytes, we get
+ * both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
+ * then the EORD.
+ */
+ tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI;
+
+ /*
+ * If using DMA mode, enable EORD interrupt to notify about RX
+ * completion.
+ */
+ if (!tup->use_rx_pio)
+ tup->ier_shadow |= TEGRA_UART_IER_EORD;
+
+ tegra_uart_write(tup, tup->ier_shadow, UART_IER);
+ return 0;
+}
+
+static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
+ bool dma_to_memory)
+{
+ if (dma_to_memory) {
+ dmaengine_terminate_all(tup->rx_dma_chan);
+ dma_release_channel(tup->rx_dma_chan);
+ dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
+ tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
+ tup->rx_dma_chan = NULL;
+ tup->rx_dma_buf_phys = 0;
+ tup->rx_dma_buf_virt = NULL;
+ } else {
+ dmaengine_terminate_all(tup->tx_dma_chan);
+ dma_release_channel(tup->tx_dma_chan);
+ dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
+ tup->tx_dma_chan = NULL;
+ tup->tx_dma_buf_phys = 0;
+ tup->tx_dma_buf_virt = NULL;
+ }
+}
+
+static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
+ bool dma_to_memory)
+{
+ struct dma_chan *dma_chan;
+ unsigned char *dma_buf;
+ dma_addr_t dma_phys;
+ int ret;
+ struct dma_slave_config dma_sconfig;
+
+ dma_chan = dma_request_chan(tup->uport.dev, dma_to_memory ? "rx" : "tx");
+ if (IS_ERR(dma_chan)) {
+ ret = PTR_ERR(dma_chan);
+ dev_err(tup->uport.dev,
+ "DMA channel alloc failed: %d\n", ret);
+ return ret;
+ }
+
+ if (dma_to_memory) {
+ dma_buf = dma_alloc_coherent(tup->uport.dev,
+ TEGRA_UART_RX_DMA_BUFFER_SIZE,
+ &dma_phys, GFP_KERNEL);
+ if (!dma_buf) {
+ dev_err(tup->uport.dev,
+ "Not able to allocate the dma buffer\n");
+ dma_release_channel(dma_chan);
+ return -ENOMEM;
+ }
+ dma_sync_single_for_device(tup->uport.dev, dma_phys,
+ TEGRA_UART_RX_DMA_BUFFER_SIZE,
+ DMA_TO_DEVICE);
+ dma_sconfig.src_addr = tup->uport.mapbase;
+ dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes;
+ tup->rx_dma_chan = dma_chan;
+ tup->rx_dma_buf_virt = dma_buf;
+ tup->rx_dma_buf_phys = dma_phys;
+ } else {
+ dma_phys = dma_map_single(tup->uport.dev,
+ tup->uport.state->xmit.buf, UART_XMIT_SIZE,
+ DMA_TO_DEVICE);
+ if (dma_mapping_error(tup->uport.dev, dma_phys)) {
+ dev_err(tup->uport.dev, "dma_map_single tx failed\n");
+ dma_release_channel(dma_chan);
+ return -ENOMEM;
+ }
+ dma_buf = tup->uport.state->xmit.buf;
+ dma_sconfig.dst_addr = tup->uport.mapbase;
+ dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+ dma_sconfig.dst_maxburst = 16;
+ tup->tx_dma_chan = dma_chan;
+ tup->tx_dma_buf_virt = dma_buf;
+ tup->tx_dma_buf_phys = dma_phys;
+ }
+
+ ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
+ if (ret < 0) {
+ dev_err(tup->uport.dev,
+ "Dma slave config failed, err = %d\n", ret);
+ tegra_uart_dma_channel_free(tup, dma_to_memory);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int tegra_uart_startup(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ int ret;
+
+ if (!tup->use_tx_pio) {
+ ret = tegra_uart_dma_channel_allocate(tup, false);
+ if (ret < 0) {
+ dev_err(u->dev, "Tx Dma allocation failed, err = %d\n",
+ ret);
+ return ret;
+ }
+ }
+
+ if (!tup->use_rx_pio) {
+ ret = tegra_uart_dma_channel_allocate(tup, true);
+ if (ret < 0) {
+ dev_err(u->dev, "Rx Dma allocation failed, err = %d\n",
+ ret);
+ goto fail_rx_dma;
+ }
+ }
+
+ ret = tegra_uart_hw_init(tup);
+ if (ret < 0) {
+ dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
+ goto fail_hw_init;
+ }
+
+ ret = request_irq(u->irq, tegra_uart_isr, 0,
+ dev_name(u->dev), tup);
+ if (ret < 0) {
+ dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
+ goto fail_hw_init;
+ }
+ return 0;
+
+fail_hw_init:
+ if (!tup->use_rx_pio)
+ tegra_uart_dma_channel_free(tup, true);
+fail_rx_dma:
+ if (!tup->use_tx_pio)
+ tegra_uart_dma_channel_free(tup, false);
+ return ret;
+}
+
+/*
+ * Flush any TX data submitted for DMA and PIO. Called when the
+ * TX circular buffer is reset.
+ */
+static void tegra_uart_flush_buffer(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+
+ tup->tx_bytes = 0;
+ if (tup->tx_dma_chan)
+ dmaengine_terminate_all(tup->tx_dma_chan);
+}
+
+static void tegra_uart_shutdown(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+
+ tegra_uart_hw_deinit(tup);
+ free_irq(u->irq, tup);
+}
+
+static void tegra_uart_enable_ms(struct uart_port *u)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+
+ if (tup->enable_modem_interrupt) {
+ tup->ier_shadow |= UART_IER_MSI;
+ tegra_uart_write(tup, tup->ier_shadow, UART_IER);
+ }
+}
+
+static void tegra_uart_set_termios(struct uart_port *u,
+ struct ktermios *termios, struct ktermios *oldtermios)
+{
+ struct tegra_uart_port *tup = to_tegra_uport(u);
+ unsigned int baud;
+ unsigned long flags;
+ unsigned int lcr;
+ int symb_bit = 1;
+ struct clk *parent_clk = clk_get_parent(tup->uart_clk);
+ unsigned long parent_clk_rate = clk_get_rate(parent_clk);
+ int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
+ int ret;
+
+ max_divider *= 16;
+ spin_lock_irqsave(&u->lock, flags);
+
+ /* Changing configuration, it is safe to stop any rx now */
+ if (tup->rts_active)
+ set_rts(tup, false);
+
+ /* Clear all interrupts as configuration is going to be changed */
+ tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
+ tegra_uart_read(tup, UART_IER);
+ tegra_uart_write(tup, 0, UART_IER);
+ tegra_uart_read(tup, UART_IER);
+
+ /* Parity */
+ lcr = tup->lcr_shadow;
+ lcr &= ~UART_LCR_PARITY;
+
+ /* CMSPAR isn't supported by this driver */
+ termios->c_cflag &= ~CMSPAR;
+
+ if ((termios->c_cflag & PARENB) == PARENB) {
+ symb_bit++;
+ if (termios->c_cflag & PARODD) {
+ lcr |= UART_LCR_PARITY;
+ lcr &= ~UART_LCR_EPAR;
+ lcr &= ~UART_LCR_SPAR;
+ } else {
+ lcr |= UART_LCR_PARITY;
+ lcr |= UART_LCR_EPAR;
+ lcr &= ~UART_LCR_SPAR;
+ }
+ }
+
+ lcr &= ~UART_LCR_WLEN8;
+ switch (termios->c_cflag & CSIZE) {
+ case CS5:
+ lcr |= UART_LCR_WLEN5;
+ symb_bit += 5;
+ break;
+ case CS6:
+ lcr |= UART_LCR_WLEN6;
+ symb_bit += 6;
+ break;
+ case CS7:
+ lcr |= UART_LCR_WLEN7;
+ symb_bit += 7;
+ break;
+ default:
+ lcr |= UART_LCR_WLEN8;
+ symb_bit += 8;
+ break;
+ }
+
+ /* Stop bits */
+ if (termios->c_cflag & CSTOPB) {
+ lcr |= UART_LCR_STOP;
+ symb_bit += 2;
+ } else {
+ lcr &= ~UART_LCR_STOP;
+ symb_bit++;
+ }
+
+ tegra_uart_write(tup, lcr, UART_LCR);
+ tup->lcr_shadow = lcr;
+ tup->symb_bit = symb_bit;
+
+ /* Baud rate. */
+ baud = uart_get_baud_rate(u, termios, oldtermios,
+ parent_clk_rate/max_divider,
+ parent_clk_rate/16);
+ spin_unlock_irqrestore(&u->lock, flags);
+ ret = tegra_set_baudrate(tup, baud);
+ if (ret < 0) {
+ dev_err(tup->uport.dev, "Failed to set baud rate\n");
+ return;
+ }
+ if (tty_termios_baud_rate(termios))
+ tty_termios_encode_baud_rate(termios, baud, baud);
+ spin_lock_irqsave(&u->lock, flags);
+
+ /* Flow control */
+ if (termios->c_cflag & CRTSCTS) {
+ tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
+ tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
+ tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
+ /* if top layer has asked to set rts active then do so here */
+ if (tup->rts_active)
+ set_rts(tup, true);
+ } else {
+ tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
+ tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
+ tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
+ }
+
+ /* update the port timeout based on new settings */
+ uart_update_timeout(u, termios->c_cflag, baud);
+
+ /* Make sure all writes have completed */
+ tegra_uart_read(tup, UART_IER);
+
+ /* Re-enable interrupt */
+ tegra_uart_write(tup, tup->ier_shadow, UART_IER);
+ tegra_uart_read(tup, UART_IER);
+
+ tup->uport.ignore_status_mask = 0;
+ /* Ignore all characters if CREAD is not set */
+ if ((termios->c_cflag & CREAD) == 0)
+ tup->uport.ignore_status_mask |= UART_LSR_DR;
+ if (termios->c_iflag & IGNBRK)
+ tup->uport.ignore_status_mask |= UART_LSR_BI;
+
+ spin_unlock_irqrestore(&u->lock, flags);
+}
+
+static const char *tegra_uart_type(struct uart_port *u)
+{
+ return TEGRA_UART_TYPE;
+}
+
+static const struct uart_ops tegra_uart_ops = {
+ .tx_empty = tegra_uart_tx_empty,
+ .set_mctrl = tegra_uart_set_mctrl,
+ .get_mctrl = tegra_uart_get_mctrl,
+ .stop_tx = tegra_uart_stop_tx,
+ .start_tx = tegra_uart_start_tx,
+ .stop_rx = tegra_uart_stop_rx,
+ .flush_buffer = tegra_uart_flush_buffer,
+ .enable_ms = tegra_uart_enable_ms,
+ .break_ctl = tegra_uart_break_ctl,
+ .startup = tegra_uart_startup,
+ .shutdown = tegra_uart_shutdown,
+ .set_termios = tegra_uart_set_termios,
+ .type = tegra_uart_type,
+ .request_port = tegra_uart_request_port,
+ .release_port = tegra_uart_release_port,
+};
+
+static struct uart_driver tegra_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = "tegra_hsuart",
+ .dev_name = "ttyTHS",
+ .cons = NULL,
+ .nr = TEGRA_UART_MAXIMUM,
+};
+
+static int tegra_uart_parse_dt(struct platform_device *pdev,
+ struct tegra_uart_port *tup)
+{
+ struct device_node *np = pdev->dev.of_node;
+ int port;
+ int ret;
+ int index;
+ u32 pval;
+ int count;
+ int n_entries;
+
+ port = of_alias_get_id(np, "serial");
+ if (port < 0) {
+ dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
+ return port;
+ }
+ tup->uport.line = port;
+
+ tup->enable_modem_interrupt = of_property_read_bool(np,
+ "nvidia,enable-modem-interrupt");
+
+ index = of_property_match_string(np, "dma-names", "rx");
+ if (index < 0) {
+ tup->use_rx_pio = true;
+ dev_info(&pdev->dev, "RX in PIO mode\n");
+ }
+ index = of_property_match_string(np, "dma-names", "tx");
+ if (index < 0) {
+ tup->use_tx_pio = true;
+ dev_info(&pdev->dev, "TX in PIO mode\n");
+ }
+
+ n_entries = of_property_count_u32_elems(np, "nvidia,adjust-baud-rates");
+ if (n_entries > 0) {
+ tup->n_adjustable_baud_rates = n_entries / 3;
+ tup->baud_tolerance =
+ devm_kzalloc(&pdev->dev, (tup->n_adjustable_baud_rates) *
+ sizeof(*tup->baud_tolerance), GFP_KERNEL);
+ if (!tup->baud_tolerance)
+ return -ENOMEM;
+ for (count = 0, index = 0; count < n_entries; count += 3,
+ index++) {
+ ret =
+ of_property_read_u32_index(np,
+ "nvidia,adjust-baud-rates",
+ count, &pval);
+ if (!ret)
+ tup->baud_tolerance[index].lower_range_baud =
+ pval;
+ ret =
+ of_property_read_u32_index(np,
+ "nvidia,adjust-baud-rates",
+ count + 1, &pval);
+ if (!ret)
+ tup->baud_tolerance[index].upper_range_baud =
+ pval;
+ ret =
+ of_property_read_u32_index(np,
+ "nvidia,adjust-baud-rates",
+ count + 2, &pval);
+ if (!ret)
+ tup->baud_tolerance[index].tolerance =
+ (s32)pval;
+ }
+ } else {
+ tup->n_adjustable_baud_rates = 0;
+ }
+
+ return 0;
+}
+
+static struct tegra_uart_chip_data tegra20_uart_chip_data = {
+ .tx_fifo_full_status = false,
+ .allow_txfifo_reset_fifo_mode = true,
+ .support_clk_src_div = false,
+ .fifo_mode_enable_status = false,
+ .uart_max_port = 5,
+ .max_dma_burst_bytes = 4,
+ .error_tolerance_low_range = -4,
+ .error_tolerance_high_range = 4,
+};
+
+static struct tegra_uart_chip_data tegra30_uart_chip_data = {
+ .tx_fifo_full_status = true,
+ .allow_txfifo_reset_fifo_mode = false,
+ .support_clk_src_div = true,
+ .fifo_mode_enable_status = false,
+ .uart_max_port = 5,
+ .max_dma_burst_bytes = 4,
+ .error_tolerance_low_range = -4,
+ .error_tolerance_high_range = 4,
+};
+
+static struct tegra_uart_chip_data tegra186_uart_chip_data = {
+ .tx_fifo_full_status = true,
+ .allow_txfifo_reset_fifo_mode = false,
+ .support_clk_src_div = true,
+ .fifo_mode_enable_status = true,
+ .uart_max_port = 8,
+ .max_dma_burst_bytes = 8,
+ .error_tolerance_low_range = 0,
+ .error_tolerance_high_range = 4,
+};
+
+static struct tegra_uart_chip_data tegra194_uart_chip_data = {
+ .tx_fifo_full_status = true,
+ .allow_txfifo_reset_fifo_mode = false,
+ .support_clk_src_div = true,
+ .fifo_mode_enable_status = true,
+ .uart_max_port = 8,
+ .max_dma_burst_bytes = 8,
+ .error_tolerance_low_range = -2,
+ .error_tolerance_high_range = 2,
+};
+
+static const struct of_device_id tegra_uart_of_match[] = {
+ {
+ .compatible = "nvidia,tegra30-hsuart",
+ .data = &tegra30_uart_chip_data,
+ }, {
+ .compatible = "nvidia,tegra20-hsuart",
+ .data = &tegra20_uart_chip_data,
+ }, {
+ .compatible = "nvidia,tegra186-hsuart",
+ .data = &tegra186_uart_chip_data,
+ }, {
+ .compatible = "nvidia,tegra194-hsuart",
+ .data = &tegra194_uart_chip_data,
+ }, {
+ },
+};
+MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
+
+static int tegra_uart_probe(struct platform_device *pdev)
+{
+ struct tegra_uart_port *tup;
+ struct uart_port *u;
+ struct resource *resource;
+ int ret;
+ const struct tegra_uart_chip_data *cdata;
+ const struct of_device_id *match;
+
+ match = of_match_device(tegra_uart_of_match, &pdev->dev);
+ if (!match) {
+ dev_err(&pdev->dev, "Error: No device match found\n");
+ return -ENODEV;
+ }
+ cdata = match->data;
+
+ tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
+ if (!tup) {
+ dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
+ return -ENOMEM;
+ }
+
+ ret = tegra_uart_parse_dt(pdev, tup);
+ if (ret < 0)
+ return ret;
+
+ u = &tup->uport;
+ u->dev = &pdev->dev;
+ u->ops = &tegra_uart_ops;
+ u->type = PORT_TEGRA;
+ u->fifosize = 32;
+ tup->cdata = cdata;
+
+ platform_set_drvdata(pdev, tup);
+ resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!resource) {
+ dev_err(&pdev->dev, "No IO memory resource\n");
+ return -ENODEV;
+ }
+
+ u->mapbase = resource->start;
+ u->membase = devm_ioremap_resource(&pdev->dev, resource);
+ if (IS_ERR(u->membase))
+ return PTR_ERR(u->membase);
+
+ tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(tup->uart_clk)) {
+ dev_err(&pdev->dev, "Couldn't get the clock\n");
+ return PTR_ERR(tup->uart_clk);
+ }
+
+ tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial");
+ if (IS_ERR(tup->rst)) {
+ dev_err(&pdev->dev, "Couldn't get the reset\n");
+ return PTR_ERR(tup->rst);
+ }
+
+ u->iotype = UPIO_MEM32;
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ return ret;
+ u->irq = ret;
+ u->regshift = 2;
+ ret = uart_add_one_port(&tegra_uart_driver, u);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
+ return ret;
+ }
+ return ret;
+}
+
+static int tegra_uart_remove(struct platform_device *pdev)
+{
+ struct tegra_uart_port *tup = platform_get_drvdata(pdev);
+ struct uart_port *u = &tup->uport;
+
+ uart_remove_one_port(&tegra_uart_driver, u);
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_uart_suspend(struct device *dev)
+{
+ struct tegra_uart_port *tup = dev_get_drvdata(dev);
+ struct uart_port *u = &tup->uport;
+
+ return uart_suspend_port(&tegra_uart_driver, u);
+}
+
+static int tegra_uart_resume(struct device *dev)
+{
+ struct tegra_uart_port *tup = dev_get_drvdata(dev);
+ struct uart_port *u = &tup->uport;
+
+ return uart_resume_port(&tegra_uart_driver, u);
+}
+#endif
+
+static const struct dev_pm_ops tegra_uart_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
+};
+
+static struct platform_driver tegra_uart_platform_driver = {
+ .probe = tegra_uart_probe,
+ .remove = tegra_uart_remove,
+ .driver = {
+ .name = "serial-tegra",
+ .of_match_table = tegra_uart_of_match,
+ .pm = &tegra_uart_pm_ops,
+ },
+};
+
+static int __init tegra_uart_init(void)
+{
+ int ret;
+ struct device_node *node;
+ const struct of_device_id *match = NULL;
+ const struct tegra_uart_chip_data *cdata = NULL;
+
+ node = of_find_matching_node(NULL, tegra_uart_of_match);
+ if (node)
+ match = of_match_node(tegra_uart_of_match, node);
+ if (match)
+ cdata = match->data;
+ if (cdata)
+ tegra_uart_driver.nr = cdata->uart_max_port;
+
+ ret = uart_register_driver(&tegra_uart_driver);
+ if (ret < 0) {
+ pr_err("Could not register %s driver\n",
+ tegra_uart_driver.driver_name);
+ return ret;
+ }
+
+ ret = platform_driver_register(&tegra_uart_platform_driver);
+ if (ret < 0) {
+ pr_err("Uart platform driver register failed, e = %d\n", ret);
+ uart_unregister_driver(&tegra_uart_driver);
+ return ret;
+ }
+ return 0;
+}
+
+static void __exit tegra_uart_exit(void)
+{
+ pr_info("Unloading tegra uart driver\n");
+ platform_driver_unregister(&tegra_uart_platform_driver);
+ uart_unregister_driver(&tegra_uart_driver);
+}
+
+module_init(tegra_uart_init);
+module_exit(tegra_uart_exit);
+
+MODULE_ALIAS("platform:serial-tegra");
+MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");