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Diffstat (limited to '')
| -rw-r--r-- | drivers/tty/serial/xilinx_uartps.c | 1729 |
1 files changed, 1729 insertions, 0 deletions
diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c new file mode 100644 index 000000000..2eff7cff5 --- /dev/null +++ b/drivers/tty/serial/xilinx_uartps.c @@ -0,0 +1,1729 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Cadence UART driver (found in Xilinx Zynq) + * + * Copyright (c) 2011 - 2014 Xilinx, Inc. + * + * This driver has originally been pushed by Xilinx using a Zynq-branding. This + * still shows in the naming of this file, the kconfig symbols and some symbols + * in the code. + */ + +#include <linux/platform_device.h> +#include <linux/serial.h> +#include <linux/console.h> +#include <linux/serial_core.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/tty_flip.h> +#include <linux/clk.h> +#include <linux/irq.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/module.h> +#include <linux/pm_runtime.h> +#include <linux/iopoll.h> + +#define CDNS_UART_TTY_NAME "ttyPS" +#define CDNS_UART_NAME "xuartps" +#define CDNS_UART_MAJOR 0 /* use dynamic node allocation */ +#define CDNS_UART_MINOR 0 /* works best with devtmpfs */ +#define CDNS_UART_NR_PORTS 16 +#define CDNS_UART_FIFO_SIZE 64 /* FIFO size */ +#define CDNS_UART_REGISTER_SPACE 0x1000 +#define TX_TIMEOUT 500000 + +/* Rx Trigger level */ +static int rx_trigger_level = 56; +module_param(rx_trigger_level, uint, 0444); +MODULE_PARM_DESC(rx_trigger_level, "Rx trigger level, 1-63 bytes"); + +/* Rx Timeout */ +static int rx_timeout = 10; +module_param(rx_timeout, uint, 0444); +MODULE_PARM_DESC(rx_timeout, "Rx timeout, 1-255"); + +/* Register offsets for the UART. */ +#define CDNS_UART_CR 0x00 /* Control Register */ +#define CDNS_UART_MR 0x04 /* Mode Register */ +#define CDNS_UART_IER 0x08 /* Interrupt Enable */ +#define CDNS_UART_IDR 0x0C /* Interrupt Disable */ +#define CDNS_UART_IMR 0x10 /* Interrupt Mask */ +#define CDNS_UART_ISR 0x14 /* Interrupt Status */ +#define CDNS_UART_BAUDGEN 0x18 /* Baud Rate Generator */ +#define CDNS_UART_RXTOUT 0x1C /* RX Timeout */ +#define CDNS_UART_RXWM 0x20 /* RX FIFO Trigger Level */ +#define CDNS_UART_MODEMCR 0x24 /* Modem Control */ +#define CDNS_UART_MODEMSR 0x28 /* Modem Status */ +#define CDNS_UART_SR 0x2C /* Channel Status */ +#define CDNS_UART_FIFO 0x30 /* FIFO */ +#define CDNS_UART_BAUDDIV 0x34 /* Baud Rate Divider */ +#define CDNS_UART_FLOWDEL 0x38 /* Flow Delay */ +#define CDNS_UART_IRRX_PWIDTH 0x3C /* IR Min Received Pulse Width */ +#define CDNS_UART_IRTX_PWIDTH 0x40 /* IR Transmitted pulse Width */ +#define CDNS_UART_TXWM 0x44 /* TX FIFO Trigger Level */ +#define CDNS_UART_RXBS 0x48 /* RX FIFO byte status register */ + +/* Control Register Bit Definitions */ +#define CDNS_UART_CR_STOPBRK 0x00000100 /* Stop TX break */ +#define CDNS_UART_CR_STARTBRK 0x00000080 /* Set TX break */ +#define CDNS_UART_CR_TX_DIS 0x00000020 /* TX disabled. */ +#define CDNS_UART_CR_TX_EN 0x00000010 /* TX enabled */ +#define CDNS_UART_CR_RX_DIS 0x00000008 /* RX disabled. */ +#define CDNS_UART_CR_RX_EN 0x00000004 /* RX enabled */ +#define CDNS_UART_CR_TXRST 0x00000002 /* TX logic reset */ +#define CDNS_UART_CR_RXRST 0x00000001 /* RX logic reset */ +#define CDNS_UART_CR_RST_TO 0x00000040 /* Restart Timeout Counter */ +#define CDNS_UART_RXBS_PARITY 0x00000001 /* Parity error status */ +#define CDNS_UART_RXBS_FRAMING 0x00000002 /* Framing error status */ +#define CDNS_UART_RXBS_BRK 0x00000004 /* Overrun error status */ + +/* + * Mode Register: + * The mode register (MR) defines the mode of transfer as well as the data + * format. If this register is modified during transmission or reception, + * data validity cannot be guaranteed. + */ +#define CDNS_UART_MR_CLKSEL 0x00000001 /* Pre-scalar selection */ +#define CDNS_UART_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */ +#define CDNS_UART_MR_CHMODE_NORM 0x00000000 /* Normal mode */ +#define CDNS_UART_MR_CHMODE_MASK 0x00000300 /* Mask for mode bits */ + +#define CDNS_UART_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */ +#define CDNS_UART_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */ + +#define CDNS_UART_MR_PARITY_NONE 0x00000020 /* No parity mode */ +#define CDNS_UART_MR_PARITY_MARK 0x00000018 /* Mark parity mode */ +#define CDNS_UART_MR_PARITY_SPACE 0x00000010 /* Space parity mode */ +#define CDNS_UART_MR_PARITY_ODD 0x00000008 /* Odd parity mode */ +#define CDNS_UART_MR_PARITY_EVEN 0x00000000 /* Even parity mode */ + +#define CDNS_UART_MR_CHARLEN_6_BIT 0x00000006 /* 6 bits data */ +#define CDNS_UART_MR_CHARLEN_7_BIT 0x00000004 /* 7 bits data */ +#define CDNS_UART_MR_CHARLEN_8_BIT 0x00000000 /* 8 bits data */ + +/* + * Interrupt Registers: + * Interrupt control logic uses the interrupt enable register (IER) and the + * interrupt disable register (IDR) to set the value of the bits in the + * interrupt mask register (IMR). The IMR determines whether to pass an + * interrupt to the interrupt status register (ISR). + * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an + * interrupt. IMR and ISR are read only, and IER and IDR are write only. + * Reading either IER or IDR returns 0x00. + * All four registers have the same bit definitions. + */ +#define CDNS_UART_IXR_TOUT 0x00000100 /* RX Timeout error interrupt */ +#define CDNS_UART_IXR_PARITY 0x00000080 /* Parity error interrupt */ +#define CDNS_UART_IXR_FRAMING 0x00000040 /* Framing error interrupt */ +#define CDNS_UART_IXR_OVERRUN 0x00000020 /* Overrun error interrupt */ +#define CDNS_UART_IXR_TXFULL 0x00000010 /* TX FIFO Full interrupt */ +#define CDNS_UART_IXR_TXEMPTY 0x00000008 /* TX FIFO empty interrupt */ +#define CDNS_UART_ISR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt */ +#define CDNS_UART_IXR_RXTRIG 0x00000001 /* RX FIFO trigger interrupt */ +#define CDNS_UART_IXR_RXFULL 0x00000004 /* RX FIFO full interrupt. */ +#define CDNS_UART_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */ +#define CDNS_UART_IXR_RXMASK 0x000021e7 /* Valid RX bit mask */ + + /* + * Do not enable parity error interrupt for the following + * reason: When parity error interrupt is enabled, each Rx + * parity error always results in 2 events. The first one + * being parity error interrupt and the second one with a + * proper Rx interrupt with the incoming data. Disabling + * parity error interrupt ensures better handling of parity + * error events. With this change, for a parity error case, we + * get a Rx interrupt with parity error set in ISR register + * and we still handle parity errors in the desired way. + */ + +#define CDNS_UART_RX_IRQS (CDNS_UART_IXR_FRAMING | \ + CDNS_UART_IXR_OVERRUN | \ + CDNS_UART_IXR_RXTRIG | \ + CDNS_UART_IXR_TOUT) + +/* Goes in read_status_mask for break detection as the HW doesn't do it*/ +#define CDNS_UART_IXR_BRK 0x00002000 + +#define CDNS_UART_RXBS_SUPPORT BIT(1) +/* + * Modem Control register: + * The read/write Modem Control register controls the interface with the modem + * or data set, or a peripheral device emulating a modem. + */ +#define CDNS_UART_MODEMCR_FCM 0x00000020 /* Automatic flow control mode */ +#define CDNS_UART_MODEMCR_RTS 0x00000002 /* Request to send output control */ +#define CDNS_UART_MODEMCR_DTR 0x00000001 /* Data Terminal Ready */ + +/* + * Modem Status register: + * The read/write Modem Status register reports the interface with the modem + * or data set, or a peripheral device emulating a modem. + */ +#define CDNS_UART_MODEMSR_DCD BIT(7) /* Data Carrier Detect */ +#define CDNS_UART_MODEMSR_RI BIT(6) /* Ting Indicator */ +#define CDNS_UART_MODEMSR_DSR BIT(5) /* Data Set Ready */ +#define CDNS_UART_MODEMSR_CTS BIT(4) /* Clear To Send */ + +/* + * Channel Status Register: + * The channel status register (CSR) is provided to enable the control logic + * to monitor the status of bits in the channel interrupt status register, + * even if these are masked out by the interrupt mask register. + */ +#define CDNS_UART_SR_RXEMPTY 0x00000002 /* RX FIFO empty */ +#define CDNS_UART_SR_TXEMPTY 0x00000008 /* TX FIFO empty */ +#define CDNS_UART_SR_TXFULL 0x00000010 /* TX FIFO full */ +#define CDNS_UART_SR_RXTRIG 0x00000001 /* Rx Trigger */ +#define CDNS_UART_SR_TACTIVE 0x00000800 /* TX state machine active */ + +/* baud dividers min/max values */ +#define CDNS_UART_BDIV_MIN 4 +#define CDNS_UART_BDIV_MAX 255 +#define CDNS_UART_CD_MAX 65535 +#define UART_AUTOSUSPEND_TIMEOUT 3000 + +/** + * struct cdns_uart - device data + * @port: Pointer to the UART port + * @uartclk: Reference clock + * @pclk: APB clock + * @cdns_uart_driver: Pointer to UART driver + * @baud: Current baud rate + * @clk_rate_change_nb: Notifier block for clock changes + * @quirks: Flags for RXBS support. + * @cts_override: Modem control state override + */ +struct cdns_uart { + struct uart_port *port; + struct clk *uartclk; + struct clk *pclk; + struct uart_driver *cdns_uart_driver; + unsigned int baud; + struct notifier_block clk_rate_change_nb; + u32 quirks; + bool cts_override; +}; +struct cdns_platform_data { + u32 quirks; +}; +#define to_cdns_uart(_nb) container_of(_nb, struct cdns_uart, \ + clk_rate_change_nb) + +/** + * cdns_uart_handle_rx - Handle the received bytes along with Rx errors. + * @dev_id: Id of the UART port + * @isrstatus: The interrupt status register value as read + * Return: None + */ +static void cdns_uart_handle_rx(void *dev_id, unsigned int isrstatus) +{ + struct uart_port *port = (struct uart_port *)dev_id; + struct cdns_uart *cdns_uart = port->private_data; + unsigned int data; + unsigned int rxbs_status = 0; + unsigned int status_mask; + unsigned int framerrprocessed = 0; + char status = TTY_NORMAL; + bool is_rxbs_support; + + is_rxbs_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; + + while ((readl(port->membase + CDNS_UART_SR) & + CDNS_UART_SR_RXEMPTY) != CDNS_UART_SR_RXEMPTY) { + if (is_rxbs_support) + rxbs_status = readl(port->membase + CDNS_UART_RXBS); + data = readl(port->membase + CDNS_UART_FIFO); + port->icount.rx++; + /* + * There is no hardware break detection in Zynq, so we interpret + * framing error with all-zeros data as a break sequence. + * Most of the time, there's another non-zero byte at the + * end of the sequence. + */ + if (!is_rxbs_support && (isrstatus & CDNS_UART_IXR_FRAMING)) { + if (!data) { + port->read_status_mask |= CDNS_UART_IXR_BRK; + framerrprocessed = 1; + continue; + } + } + if (is_rxbs_support && (rxbs_status & CDNS_UART_RXBS_BRK)) { + port->icount.brk++; + status = TTY_BREAK; + if (uart_handle_break(port)) + continue; + } + + isrstatus &= port->read_status_mask; + isrstatus &= ~port->ignore_status_mask; + status_mask = port->read_status_mask; + status_mask &= ~port->ignore_status_mask; + + if (data && + (port->read_status_mask & CDNS_UART_IXR_BRK)) { + port->read_status_mask &= ~CDNS_UART_IXR_BRK; + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } + + if (uart_handle_sysrq_char(port, data)) + continue; + + if (is_rxbs_support) { + if ((rxbs_status & CDNS_UART_RXBS_PARITY) + && (status_mask & CDNS_UART_IXR_PARITY)) { + port->icount.parity++; + status = TTY_PARITY; + } + if ((rxbs_status & CDNS_UART_RXBS_FRAMING) + && (status_mask & CDNS_UART_IXR_PARITY)) { + port->icount.frame++; + status = TTY_FRAME; + } + } else { + if (isrstatus & CDNS_UART_IXR_PARITY) { + port->icount.parity++; + status = TTY_PARITY; + } + if ((isrstatus & CDNS_UART_IXR_FRAMING) && + !framerrprocessed) { + port->icount.frame++; + status = TTY_FRAME; + } + } + if (isrstatus & CDNS_UART_IXR_OVERRUN) { + port->icount.overrun++; + tty_insert_flip_char(&port->state->port, 0, + TTY_OVERRUN); + } + tty_insert_flip_char(&port->state->port, data, status); + isrstatus = 0; + } + + tty_flip_buffer_push(&port->state->port); +} + +/** + * cdns_uart_handle_tx - Handle the bytes to be Txed. + * @dev_id: Id of the UART port + * Return: None + */ +static void cdns_uart_handle_tx(void *dev_id) +{ + struct uart_port *port = (struct uart_port *)dev_id; + struct circ_buf *xmit = &port->state->xmit; + unsigned int numbytes; + + if (uart_circ_empty(xmit)) { + writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR); + return; + } + + numbytes = port->fifosize; + while (numbytes && !uart_circ_empty(xmit) && + !(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)) { + + writel(xmit->buf[xmit->tail], port->membase + CDNS_UART_FIFO); + + port->icount.tx++; + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + numbytes--; + } + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(port); +} + +/** + * cdns_uart_isr - Interrupt handler + * @irq: Irq number + * @dev_id: Id of the port + * + * Return: IRQHANDLED + */ +static irqreturn_t cdns_uart_isr(int irq, void *dev_id) +{ + struct uart_port *port = (struct uart_port *)dev_id; + unsigned int isrstatus; + + spin_lock(&port->lock); + + /* Read the interrupt status register to determine which + * interrupt(s) is/are active and clear them. + */ + isrstatus = readl(port->membase + CDNS_UART_ISR); + writel(isrstatus, port->membase + CDNS_UART_ISR); + + if (isrstatus & CDNS_UART_IXR_TXEMPTY) { + cdns_uart_handle_tx(dev_id); + isrstatus &= ~CDNS_UART_IXR_TXEMPTY; + } + + isrstatus &= port->read_status_mask; + isrstatus &= ~port->ignore_status_mask; + /* + * Skip RX processing if RX is disabled as RXEMPTY will never be set + * as read bytes will not be removed from the FIFO. + */ + if (isrstatus & CDNS_UART_IXR_RXMASK && + !(readl(port->membase + CDNS_UART_CR) & CDNS_UART_CR_RX_DIS)) + cdns_uart_handle_rx(dev_id, isrstatus); + + spin_unlock(&port->lock); + return IRQ_HANDLED; +} + +/** + * cdns_uart_calc_baud_divs - Calculate baud rate divisors + * @clk: UART module input clock + * @baud: Desired baud rate + * @rbdiv: BDIV value (return value) + * @rcd: CD value (return value) + * @div8: Value for clk_sel bit in mod (return value) + * Return: baud rate, requested baud when possible, or actual baud when there + * was too much error, zero if no valid divisors are found. + * + * Formula to obtain baud rate is + * baud_tx/rx rate = clk/CD * (BDIV + 1) + * input_clk = (Uart User Defined Clock or Apb Clock) + * depends on UCLKEN in MR Reg + * clk = input_clk or input_clk/8; + * depends on CLKS in MR reg + * CD and BDIV depends on values in + * baud rate generate register + * baud rate clock divisor register + */ +static unsigned int cdns_uart_calc_baud_divs(unsigned int clk, + unsigned int baud, u32 *rbdiv, u32 *rcd, int *div8) +{ + u32 cd, bdiv; + unsigned int calc_baud; + unsigned int bestbaud = 0; + unsigned int bauderror; + unsigned int besterror = ~0; + + if (baud < clk / ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX)) { + *div8 = 1; + clk /= 8; + } else { + *div8 = 0; + } + + for (bdiv = CDNS_UART_BDIV_MIN; bdiv <= CDNS_UART_BDIV_MAX; bdiv++) { + cd = DIV_ROUND_CLOSEST(clk, baud * (bdiv + 1)); + if (cd < 1 || cd > CDNS_UART_CD_MAX) + continue; + + calc_baud = clk / (cd * (bdiv + 1)); + + if (baud > calc_baud) + bauderror = baud - calc_baud; + else + bauderror = calc_baud - baud; + + if (besterror > bauderror) { + *rbdiv = bdiv; + *rcd = cd; + bestbaud = calc_baud; + besterror = bauderror; + } + } + /* use the values when percent error is acceptable */ + if (((besterror * 100) / baud) < 3) + bestbaud = baud; + + return bestbaud; +} + +/** + * cdns_uart_set_baud_rate - Calculate and set the baud rate + * @port: Handle to the uart port structure + * @baud: Baud rate to set + * Return: baud rate, requested baud when possible, or actual baud when there + * was too much error, zero if no valid divisors are found. + */ +static unsigned int cdns_uart_set_baud_rate(struct uart_port *port, + unsigned int baud) +{ + unsigned int calc_baud; + u32 cd = 0, bdiv = 0; + u32 mreg; + int div8; + struct cdns_uart *cdns_uart = port->private_data; + + calc_baud = cdns_uart_calc_baud_divs(port->uartclk, baud, &bdiv, &cd, + &div8); + + /* Write new divisors to hardware */ + mreg = readl(port->membase + CDNS_UART_MR); + if (div8) + mreg |= CDNS_UART_MR_CLKSEL; + else + mreg &= ~CDNS_UART_MR_CLKSEL; + writel(mreg, port->membase + CDNS_UART_MR); + writel(cd, port->membase + CDNS_UART_BAUDGEN); + writel(bdiv, port->membase + CDNS_UART_BAUDDIV); + cdns_uart->baud = baud; + + return calc_baud; +} + +#ifdef CONFIG_COMMON_CLK +/** + * cdns_uart_clk_notifier_cb - Clock notifier callback + * @nb: Notifier block + * @event: Notify event + * @data: Notifier data + * Return: NOTIFY_OK or NOTIFY_DONE on success, NOTIFY_BAD on error. + */ +static int cdns_uart_clk_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + u32 ctrl_reg; + struct uart_port *port; + int locked = 0; + struct clk_notifier_data *ndata = data; + struct cdns_uart *cdns_uart = to_cdns_uart(nb); + unsigned long flags; + + port = cdns_uart->port; + if (port->suspended) + return NOTIFY_OK; + + switch (event) { + case PRE_RATE_CHANGE: + { + u32 bdiv, cd; + int div8; + + /* + * Find out if current baud-rate can be achieved with new clock + * frequency. + */ + if (!cdns_uart_calc_baud_divs(ndata->new_rate, cdns_uart->baud, + &bdiv, &cd, &div8)) { + dev_warn(port->dev, "clock rate change rejected\n"); + return NOTIFY_BAD; + } + + spin_lock_irqsave(&cdns_uart->port->lock, flags); + + /* Disable the TX and RX to set baud rate */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + spin_unlock_irqrestore(&cdns_uart->port->lock, flags); + + return NOTIFY_OK; + } + case POST_RATE_CHANGE: + /* + * Set clk dividers to generate correct baud with new clock + * frequency. + */ + + spin_lock_irqsave(&cdns_uart->port->lock, flags); + + locked = 1; + port->uartclk = ndata->new_rate; + + cdns_uart->baud = cdns_uart_set_baud_rate(cdns_uart->port, + cdns_uart->baud); + fallthrough; + case ABORT_RATE_CHANGE: + if (!locked) + spin_lock_irqsave(&cdns_uart->port->lock, flags); + + /* Set TX/RX Reset */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + while (readl(port->membase + CDNS_UART_CR) & + (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) + cpu_relax(); + + /* + * Clear the RX disable and TX disable bits and then set the TX + * enable bit and RX enable bit to enable the transmitter and + * receiver. + */ + writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); + ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + spin_unlock_irqrestore(&cdns_uart->port->lock, flags); + + return NOTIFY_OK; + default: + return NOTIFY_DONE; + } +} +#endif + +/** + * cdns_uart_start_tx - Start transmitting bytes + * @port: Handle to the uart port structure + */ +static void cdns_uart_start_tx(struct uart_port *port) +{ + unsigned int status; + + if (uart_tx_stopped(port)) + return; + + /* + * Set the TX enable bit and clear the TX disable bit to enable the + * transmitter. + */ + status = readl(port->membase + CDNS_UART_CR); + status &= ~CDNS_UART_CR_TX_DIS; + status |= CDNS_UART_CR_TX_EN; + writel(status, port->membase + CDNS_UART_CR); + + if (uart_circ_empty(&port->state->xmit)) + return; + + writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR); + + cdns_uart_handle_tx(port); + + /* Enable the TX Empty interrupt */ + writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IER); +} + +/** + * cdns_uart_stop_tx - Stop TX + * @port: Handle to the uart port structure + */ +static void cdns_uart_stop_tx(struct uart_port *port) +{ + unsigned int regval; + + regval = readl(port->membase + CDNS_UART_CR); + regval |= CDNS_UART_CR_TX_DIS; + /* Disable the transmitter */ + writel(regval, port->membase + CDNS_UART_CR); +} + +/** + * cdns_uart_stop_rx - Stop RX + * @port: Handle to the uart port structure + */ +static void cdns_uart_stop_rx(struct uart_port *port) +{ + unsigned int regval; + + /* Disable RX IRQs */ + writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IDR); + + /* Disable the receiver */ + regval = readl(port->membase + CDNS_UART_CR); + regval |= CDNS_UART_CR_RX_DIS; + writel(regval, port->membase + CDNS_UART_CR); +} + +/** + * cdns_uart_tx_empty - Check whether TX is empty + * @port: Handle to the uart port structure + * + * Return: TIOCSER_TEMT on success, 0 otherwise + */ +static unsigned int cdns_uart_tx_empty(struct uart_port *port) +{ + unsigned int status; + + status = readl(port->membase + CDNS_UART_SR) & + (CDNS_UART_SR_TXEMPTY | CDNS_UART_SR_TACTIVE); + return (status == CDNS_UART_SR_TXEMPTY) ? TIOCSER_TEMT : 0; +} + +/** + * cdns_uart_break_ctl - Based on the input ctl we have to start or stop + * transmitting char breaks + * @port: Handle to the uart port structure + * @ctl: Value based on which start or stop decision is taken + */ +static void cdns_uart_break_ctl(struct uart_port *port, int ctl) +{ + unsigned int status; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + status = readl(port->membase + CDNS_UART_CR); + + if (ctl == -1) + writel(CDNS_UART_CR_STARTBRK | status, + port->membase + CDNS_UART_CR); + else { + if ((status & CDNS_UART_CR_STOPBRK) == 0) + writel(CDNS_UART_CR_STOPBRK | status, + port->membase + CDNS_UART_CR); + } + spin_unlock_irqrestore(&port->lock, flags); +} + +/** + * cdns_uart_set_termios - termios operations, handling data length, parity, + * stop bits, flow control, baud rate + * @port: Handle to the uart port structure + * @termios: Handle to the input termios structure + * @old: Values of the previously saved termios structure + */ +static void cdns_uart_set_termios(struct uart_port *port, + struct ktermios *termios, + const struct ktermios *old) +{ + u32 cval = 0; + unsigned int baud, minbaud, maxbaud; + unsigned long flags; + unsigned int ctrl_reg, mode_reg; + + spin_lock_irqsave(&port->lock, flags); + + /* Disable the TX and RX to set baud rate */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + /* + * Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk + * min and max baud should be calculated here based on port->uartclk. + * this way we get a valid baud and can safely call set_baud() + */ + minbaud = port->uartclk / + ((CDNS_UART_BDIV_MAX + 1) * CDNS_UART_CD_MAX * 8); + maxbaud = port->uartclk / (CDNS_UART_BDIV_MIN + 1); + baud = uart_get_baud_rate(port, termios, old, minbaud, maxbaud); + baud = cdns_uart_set_baud_rate(port, baud); + if (tty_termios_baud_rate(termios)) + tty_termios_encode_baud_rate(termios, baud, baud); + + /* Update the per-port timeout. */ + uart_update_timeout(port, termios->c_cflag, baud); + + /* Set TX/RX Reset */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + while (readl(port->membase + CDNS_UART_CR) & + (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) + cpu_relax(); + + /* + * Clear the RX disable and TX disable bits and then set the TX enable + * bit and RX enable bit to enable the transmitter and receiver. + */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); + ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); + + port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | + CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; + port->ignore_status_mask = 0; + + if (termios->c_iflag & INPCK) + port->read_status_mask |= CDNS_UART_IXR_PARITY | + CDNS_UART_IXR_FRAMING; + + if (termios->c_iflag & IGNPAR) + port->ignore_status_mask |= CDNS_UART_IXR_PARITY | + CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; + + /* ignore all characters if CREAD is not set */ + if ((termios->c_cflag & CREAD) == 0) + port->ignore_status_mask |= CDNS_UART_IXR_RXTRIG | + CDNS_UART_IXR_TOUT | CDNS_UART_IXR_PARITY | + CDNS_UART_IXR_FRAMING | CDNS_UART_IXR_OVERRUN; + + mode_reg = readl(port->membase + CDNS_UART_MR); + + /* Handling Data Size */ + switch (termios->c_cflag & CSIZE) { + case CS6: + cval |= CDNS_UART_MR_CHARLEN_6_BIT; + break; + case CS7: + cval |= CDNS_UART_MR_CHARLEN_7_BIT; + break; + default: + case CS8: + cval |= CDNS_UART_MR_CHARLEN_8_BIT; + termios->c_cflag &= ~CSIZE; + termios->c_cflag |= CS8; + break; + } + + /* Handling Parity and Stop Bits length */ + if (termios->c_cflag & CSTOPB) + cval |= CDNS_UART_MR_STOPMODE_2_BIT; /* 2 STOP bits */ + else + cval |= CDNS_UART_MR_STOPMODE_1_BIT; /* 1 STOP bit */ + + if (termios->c_cflag & PARENB) { + /* Mark or Space parity */ + if (termios->c_cflag & CMSPAR) { + if (termios->c_cflag & PARODD) + cval |= CDNS_UART_MR_PARITY_MARK; + else + cval |= CDNS_UART_MR_PARITY_SPACE; + } else { + if (termios->c_cflag & PARODD) + cval |= CDNS_UART_MR_PARITY_ODD; + else + cval |= CDNS_UART_MR_PARITY_EVEN; + } + } else { + cval |= CDNS_UART_MR_PARITY_NONE; + } + cval |= mode_reg & 1; + writel(cval, port->membase + CDNS_UART_MR); + + cval = readl(port->membase + CDNS_UART_MODEMCR); + if (termios->c_cflag & CRTSCTS) + cval |= CDNS_UART_MODEMCR_FCM; + else + cval &= ~CDNS_UART_MODEMCR_FCM; + writel(cval, port->membase + CDNS_UART_MODEMCR); + + spin_unlock_irqrestore(&port->lock, flags); +} + +/** + * cdns_uart_startup - Called when an application opens a cdns_uart port + * @port: Handle to the uart port structure + * + * Return: 0 on success, negative errno otherwise + */ +static int cdns_uart_startup(struct uart_port *port) +{ + struct cdns_uart *cdns_uart = port->private_data; + bool is_brk_support; + int ret; + unsigned long flags; + unsigned int status = 0; + + is_brk_support = cdns_uart->quirks & CDNS_UART_RXBS_SUPPORT; + + spin_lock_irqsave(&port->lock, flags); + + /* Disable the TX and RX */ + writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, + port->membase + CDNS_UART_CR); + + /* Set the Control Register with TX/RX Enable, TX/RX Reset, + * no break chars. + */ + writel(CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST, + port->membase + CDNS_UART_CR); + + while (readl(port->membase + CDNS_UART_CR) & + (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) + cpu_relax(); + + /* + * Clear the RX disable bit and then set the RX enable bit to enable + * the receiver. + */ + status = readl(port->membase + CDNS_UART_CR); + status &= ~CDNS_UART_CR_RX_DIS; + status |= CDNS_UART_CR_RX_EN; + writel(status, port->membase + CDNS_UART_CR); + + /* Set the Mode Register with normal mode,8 data bits,1 stop bit, + * no parity. + */ + writel(CDNS_UART_MR_CHMODE_NORM | CDNS_UART_MR_STOPMODE_1_BIT + | CDNS_UART_MR_PARITY_NONE | CDNS_UART_MR_CHARLEN_8_BIT, + port->membase + CDNS_UART_MR); + + /* + * Set the RX FIFO Trigger level to use most of the FIFO, but it + * can be tuned with a module parameter + */ + writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); + + /* + * Receive Timeout register is enabled but it + * can be tuned with a module parameter + */ + writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); + + /* Clear out any pending interrupts before enabling them */ + writel(readl(port->membase + CDNS_UART_ISR), + port->membase + CDNS_UART_ISR); + + spin_unlock_irqrestore(&port->lock, flags); + + ret = request_irq(port->irq, cdns_uart_isr, 0, CDNS_UART_NAME, port); + if (ret) { + dev_err(port->dev, "request_irq '%d' failed with %d\n", + port->irq, ret); + return ret; + } + + /* Set the Interrupt Registers with desired interrupts */ + if (is_brk_support) + writel(CDNS_UART_RX_IRQS | CDNS_UART_IXR_BRK, + port->membase + CDNS_UART_IER); + else + writel(CDNS_UART_RX_IRQS, port->membase + CDNS_UART_IER); + + return 0; +} + +/** + * cdns_uart_shutdown - Called when an application closes a cdns_uart port + * @port: Handle to the uart port structure + */ +static void cdns_uart_shutdown(struct uart_port *port) +{ + int status; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + /* Disable interrupts */ + status = readl(port->membase + CDNS_UART_IMR); + writel(status, port->membase + CDNS_UART_IDR); + writel(0xffffffff, port->membase + CDNS_UART_ISR); + + /* Disable the TX and RX */ + writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS, + port->membase + CDNS_UART_CR); + + spin_unlock_irqrestore(&port->lock, flags); + + free_irq(port->irq, port); +} + +/** + * cdns_uart_type - Set UART type to cdns_uart port + * @port: Handle to the uart port structure + * + * Return: string on success, NULL otherwise + */ +static const char *cdns_uart_type(struct uart_port *port) +{ + return port->type == PORT_XUARTPS ? CDNS_UART_NAME : NULL; +} + +/** + * cdns_uart_verify_port - Verify the port params + * @port: Handle to the uart port structure + * @ser: Handle to the structure whose members are compared + * + * Return: 0 on success, negative errno otherwise. + */ +static int cdns_uart_verify_port(struct uart_port *port, + struct serial_struct *ser) +{ + if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS) + return -EINVAL; + if (port->irq != ser->irq) + return -EINVAL; + if (ser->io_type != UPIO_MEM) + return -EINVAL; + if (port->iobase != ser->port) + return -EINVAL; + if (ser->hub6 != 0) + return -EINVAL; + return 0; +} + +/** + * cdns_uart_request_port - Claim the memory region attached to cdns_uart port, + * called when the driver adds a cdns_uart port via + * uart_add_one_port() + * @port: Handle to the uart port structure + * + * Return: 0 on success, negative errno otherwise. + */ +static int cdns_uart_request_port(struct uart_port *port) +{ + if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE, + CDNS_UART_NAME)) { + return -ENOMEM; + } + + port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE); + if (!port->membase) { + dev_err(port->dev, "Unable to map registers\n"); + release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); + return -ENOMEM; + } + return 0; +} + +/** + * cdns_uart_release_port - Release UART port + * @port: Handle to the uart port structure + * + * Release the memory region attached to a cdns_uart port. Called when the + * driver removes a cdns_uart port via uart_remove_one_port(). + */ +static void cdns_uart_release_port(struct uart_port *port) +{ + release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE); + iounmap(port->membase); + port->membase = NULL; +} + +/** + * cdns_uart_config_port - Configure UART port + * @port: Handle to the uart port structure + * @flags: If any + */ +static void cdns_uart_config_port(struct uart_port *port, int flags) +{ + if (flags & UART_CONFIG_TYPE && cdns_uart_request_port(port) == 0) + port->type = PORT_XUARTPS; +} + +/** + * cdns_uart_get_mctrl - Get the modem control state + * @port: Handle to the uart port structure + * + * Return: the modem control state + */ +static unsigned int cdns_uart_get_mctrl(struct uart_port *port) +{ + u32 val; + unsigned int mctrl = 0; + struct cdns_uart *cdns_uart_data = port->private_data; + + if (cdns_uart_data->cts_override) + return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR; + + val = readl(port->membase + CDNS_UART_MODEMSR); + if (val & CDNS_UART_MODEMSR_CTS) + mctrl |= TIOCM_CTS; + if (val & CDNS_UART_MODEMSR_DSR) + mctrl |= TIOCM_DSR; + if (val & CDNS_UART_MODEMSR_RI) + mctrl |= TIOCM_RNG; + if (val & CDNS_UART_MODEMSR_DCD) + mctrl |= TIOCM_CAR; + + return mctrl; +} + +static void cdns_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) +{ + u32 val; + u32 mode_reg; + struct cdns_uart *cdns_uart_data = port->private_data; + + if (cdns_uart_data->cts_override) + return; + + val = readl(port->membase + CDNS_UART_MODEMCR); + mode_reg = readl(port->membase + CDNS_UART_MR); + + val &= ~(CDNS_UART_MODEMCR_RTS | CDNS_UART_MODEMCR_DTR); + mode_reg &= ~CDNS_UART_MR_CHMODE_MASK; + + if (mctrl & TIOCM_RTS) + val |= CDNS_UART_MODEMCR_RTS; + if (mctrl & TIOCM_DTR) + val |= CDNS_UART_MODEMCR_DTR; + if (mctrl & TIOCM_LOOP) + mode_reg |= CDNS_UART_MR_CHMODE_L_LOOP; + else + mode_reg |= CDNS_UART_MR_CHMODE_NORM; + + writel(val, port->membase + CDNS_UART_MODEMCR); + writel(mode_reg, port->membase + CDNS_UART_MR); +} + +#ifdef CONFIG_CONSOLE_POLL +static int cdns_uart_poll_get_char(struct uart_port *port) +{ + int c; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + /* Check if FIFO is empty */ + if (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_RXEMPTY) + c = NO_POLL_CHAR; + else /* Read a character */ + c = (unsigned char) readl(port->membase + CDNS_UART_FIFO); + + spin_unlock_irqrestore(&port->lock, flags); + + return c; +} + +static void cdns_uart_poll_put_char(struct uart_port *port, unsigned char c) +{ + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + + /* Wait until FIFO is empty */ + while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) + cpu_relax(); + + /* Write a character */ + writel(c, port->membase + CDNS_UART_FIFO); + + /* Wait until FIFO is empty */ + while (!(readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXEMPTY)) + cpu_relax(); + + spin_unlock_irqrestore(&port->lock, flags); +} +#endif + +static void cdns_uart_pm(struct uart_port *port, unsigned int state, + unsigned int oldstate) +{ + switch (state) { + case UART_PM_STATE_OFF: + pm_runtime_mark_last_busy(port->dev); + pm_runtime_put_autosuspend(port->dev); + break; + default: + pm_runtime_get_sync(port->dev); + break; + } +} + +static const struct uart_ops cdns_uart_ops = { + .set_mctrl = cdns_uart_set_mctrl, + .get_mctrl = cdns_uart_get_mctrl, + .start_tx = cdns_uart_start_tx, + .stop_tx = cdns_uart_stop_tx, + .stop_rx = cdns_uart_stop_rx, + .tx_empty = cdns_uart_tx_empty, + .break_ctl = cdns_uart_break_ctl, + .set_termios = cdns_uart_set_termios, + .startup = cdns_uart_startup, + .shutdown = cdns_uart_shutdown, + .pm = cdns_uart_pm, + .type = cdns_uart_type, + .verify_port = cdns_uart_verify_port, + .request_port = cdns_uart_request_port, + .release_port = cdns_uart_release_port, + .config_port = cdns_uart_config_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = cdns_uart_poll_get_char, + .poll_put_char = cdns_uart_poll_put_char, +#endif +}; + +static struct uart_driver cdns_uart_uart_driver; + +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE +/** + * cdns_uart_console_putchar - write the character to the FIFO buffer + * @port: Handle to the uart port structure + * @ch: Character to be written + */ +static void cdns_uart_console_putchar(struct uart_port *port, unsigned char ch) +{ + unsigned int ctrl_reg; + unsigned long timeout; + + timeout = jiffies + msecs_to_jiffies(1000); + while (1) { + ctrl_reg = readl(port->membase + CDNS_UART_CR); + if (!(ctrl_reg & CDNS_UART_CR_TX_DIS)) + break; + if (time_after(jiffies, timeout)) { + dev_warn(port->dev, + "timeout waiting for Enable\n"); + return; + } + cpu_relax(); + } + + timeout = jiffies + msecs_to_jiffies(1000); + while (1) { + ctrl_reg = readl(port->membase + CDNS_UART_SR); + + if (!(ctrl_reg & CDNS_UART_SR_TXFULL)) + break; + if (time_after(jiffies, timeout)) { + dev_warn(port->dev, + "timeout waiting for TX fifo\n"); + return; + } + cpu_relax(); + } + writel(ch, port->membase + CDNS_UART_FIFO); +} + +static void cdns_early_write(struct console *con, const char *s, + unsigned int n) +{ + struct earlycon_device *dev = con->data; + + uart_console_write(&dev->port, s, n, cdns_uart_console_putchar); +} + +static int __init cdns_early_console_setup(struct earlycon_device *device, + const char *opt) +{ + struct uart_port *port = &device->port; + + if (!port->membase) + return -ENODEV; + + /* initialise control register */ + writel(CDNS_UART_CR_TX_EN|CDNS_UART_CR_TXRST|CDNS_UART_CR_RXRST, + port->membase + CDNS_UART_CR); + + /* only set baud if specified on command line - otherwise + * assume it has been initialized by a boot loader. + */ + if (port->uartclk && device->baud) { + u32 cd = 0, bdiv = 0; + u32 mr; + int div8; + + cdns_uart_calc_baud_divs(port->uartclk, device->baud, + &bdiv, &cd, &div8); + mr = CDNS_UART_MR_PARITY_NONE; + if (div8) + mr |= CDNS_UART_MR_CLKSEL; + + writel(mr, port->membase + CDNS_UART_MR); + writel(cd, port->membase + CDNS_UART_BAUDGEN); + writel(bdiv, port->membase + CDNS_UART_BAUDDIV); + } + + device->con->write = cdns_early_write; + + return 0; +} +OF_EARLYCON_DECLARE(cdns, "xlnx,xuartps", cdns_early_console_setup); +OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p8", cdns_early_console_setup); +OF_EARLYCON_DECLARE(cdns, "cdns,uart-r1p12", cdns_early_console_setup); +OF_EARLYCON_DECLARE(cdns, "xlnx,zynqmp-uart", cdns_early_console_setup); + + +/* Static pointer to console port */ +static struct uart_port *console_port; + +/** + * cdns_uart_console_write - perform write operation + * @co: Console handle + * @s: Pointer to character array + * @count: No of characters + */ +static void cdns_uart_console_write(struct console *co, const char *s, + unsigned int count) +{ + struct uart_port *port = console_port; + unsigned long flags; + unsigned int imr, ctrl; + int locked = 1; + + if (port->sysrq) + locked = 0; + else if (oops_in_progress) + locked = spin_trylock_irqsave(&port->lock, flags); + else + spin_lock_irqsave(&port->lock, flags); + + /* save and disable interrupt */ + imr = readl(port->membase + CDNS_UART_IMR); + writel(imr, port->membase + CDNS_UART_IDR); + + /* + * Make sure that the tx part is enabled. Set the TX enable bit and + * clear the TX disable bit to enable the transmitter. + */ + ctrl = readl(port->membase + CDNS_UART_CR); + ctrl &= ~CDNS_UART_CR_TX_DIS; + ctrl |= CDNS_UART_CR_TX_EN; + writel(ctrl, port->membase + CDNS_UART_CR); + + uart_console_write(port, s, count, cdns_uart_console_putchar); + while (cdns_uart_tx_empty(port) != TIOCSER_TEMT) + cpu_relax(); + + /* restore interrupt state */ + writel(imr, port->membase + CDNS_UART_IER); + + if (locked) + spin_unlock_irqrestore(&port->lock, flags); +} + +/** + * cdns_uart_console_setup - Initialize the uart to default config + * @co: Console handle + * @options: Initial settings of uart + * + * Return: 0 on success, negative errno otherwise. + */ +static int cdns_uart_console_setup(struct console *co, char *options) +{ + struct uart_port *port = console_port; + + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + unsigned long time_out; + + if (!port->membase) { + pr_debug("console on " CDNS_UART_TTY_NAME "%i not present\n", + co->index); + return -ENODEV; + } + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + /* Wait for tx_empty before setting up the console */ + time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT); + + while (time_before(jiffies, time_out) && + cdns_uart_tx_empty(port) != TIOCSER_TEMT) + cpu_relax(); + + return uart_set_options(port, co, baud, parity, bits, flow); +} + +static struct console cdns_uart_console = { + .name = CDNS_UART_TTY_NAME, + .write = cdns_uart_console_write, + .device = uart_console_device, + .setup = cdns_uart_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */ + .data = &cdns_uart_uart_driver, +}; +#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */ + +#ifdef CONFIG_PM_SLEEP +/** + * cdns_uart_suspend - suspend event + * @device: Pointer to the device structure + * + * Return: 0 + */ +static int cdns_uart_suspend(struct device *device) +{ + struct uart_port *port = dev_get_drvdata(device); + struct cdns_uart *cdns_uart = port->private_data; + int may_wake; + + may_wake = device_may_wakeup(device); + + if (console_suspend_enabled && uart_console(port) && may_wake) { + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + /* Empty the receive FIFO 1st before making changes */ + while (!(readl(port->membase + CDNS_UART_SR) & + CDNS_UART_SR_RXEMPTY)) + readl(port->membase + CDNS_UART_FIFO); + /* set RX trigger level to 1 */ + writel(1, port->membase + CDNS_UART_RXWM); + /* disable RX timeout interrups */ + writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IDR); + spin_unlock_irqrestore(&port->lock, flags); + } + + /* + * Call the API provided in serial_core.c file which handles + * the suspend. + */ + return uart_suspend_port(cdns_uart->cdns_uart_driver, port); +} + +/** + * cdns_uart_resume - Resume after a previous suspend + * @device: Pointer to the device structure + * + * Return: 0 + */ +static int cdns_uart_resume(struct device *device) +{ + struct uart_port *port = dev_get_drvdata(device); + struct cdns_uart *cdns_uart = port->private_data; + unsigned long flags; + u32 ctrl_reg; + int may_wake; + int ret; + + may_wake = device_may_wakeup(device); + + if (console_suspend_enabled && uart_console(port) && !may_wake) { + ret = clk_enable(cdns_uart->pclk); + if (ret) + return ret; + + ret = clk_enable(cdns_uart->uartclk); + if (ret) { + clk_disable(cdns_uart->pclk); + return ret; + } + + spin_lock_irqsave(&port->lock, flags); + + /* Set TX/RX Reset */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg |= CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + while (readl(port->membase + CDNS_UART_CR) & + (CDNS_UART_CR_TXRST | CDNS_UART_CR_RXRST)) + cpu_relax(); + + /* restore rx timeout value */ + writel(rx_timeout, port->membase + CDNS_UART_RXTOUT); + /* Enable Tx/Rx */ + ctrl_reg = readl(port->membase + CDNS_UART_CR); + ctrl_reg &= ~(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS); + ctrl_reg |= CDNS_UART_CR_TX_EN | CDNS_UART_CR_RX_EN; + writel(ctrl_reg, port->membase + CDNS_UART_CR); + + clk_disable(cdns_uart->uartclk); + clk_disable(cdns_uart->pclk); + spin_unlock_irqrestore(&port->lock, flags); + } else { + spin_lock_irqsave(&port->lock, flags); + /* restore original rx trigger level */ + writel(rx_trigger_level, port->membase + CDNS_UART_RXWM); + /* enable RX timeout interrupt */ + writel(CDNS_UART_IXR_TOUT, port->membase + CDNS_UART_IER); + spin_unlock_irqrestore(&port->lock, flags); + } + + return uart_resume_port(cdns_uart->cdns_uart_driver, port); +} +#endif /* ! CONFIG_PM_SLEEP */ +static int __maybe_unused cdns_runtime_suspend(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + struct cdns_uart *cdns_uart = port->private_data; + + clk_disable(cdns_uart->uartclk); + clk_disable(cdns_uart->pclk); + return 0; +}; + +static int __maybe_unused cdns_runtime_resume(struct device *dev) +{ + struct uart_port *port = dev_get_drvdata(dev); + struct cdns_uart *cdns_uart = port->private_data; + int ret; + + ret = clk_enable(cdns_uart->pclk); + if (ret) + return ret; + + ret = clk_enable(cdns_uart->uartclk); + if (ret) { + clk_disable(cdns_uart->pclk); + return ret; + } + return 0; +}; + +static const struct dev_pm_ops cdns_uart_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(cdns_uart_suspend, cdns_uart_resume) + SET_RUNTIME_PM_OPS(cdns_runtime_suspend, + cdns_runtime_resume, NULL) +}; + +static const struct cdns_platform_data zynqmp_uart_def = { + .quirks = CDNS_UART_RXBS_SUPPORT, }; + +/* Match table for of_platform binding */ +static const struct of_device_id cdns_uart_of_match[] = { + { .compatible = "xlnx,xuartps", }, + { .compatible = "cdns,uart-r1p8", }, + { .compatible = "cdns,uart-r1p12", .data = &zynqmp_uart_def }, + { .compatible = "xlnx,zynqmp-uart", .data = &zynqmp_uart_def }, + {} +}; +MODULE_DEVICE_TABLE(of, cdns_uart_of_match); + +/* Temporary variable for storing number of instances */ +static int instances; + +/** + * cdns_uart_probe - Platform driver probe + * @pdev: Pointer to the platform device structure + * + * Return: 0 on success, negative errno otherwise + */ +static int cdns_uart_probe(struct platform_device *pdev) +{ + int rc, id, irq; + struct uart_port *port; + struct resource *res; + struct cdns_uart *cdns_uart_data; + const struct of_device_id *match; + + cdns_uart_data = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_data), + GFP_KERNEL); + if (!cdns_uart_data) + return -ENOMEM; + port = devm_kzalloc(&pdev->dev, sizeof(*port), GFP_KERNEL); + if (!port) + return -ENOMEM; + + /* Look for a serialN alias */ + id = of_alias_get_id(pdev->dev.of_node, "serial"); + if (id < 0) + id = 0; + + if (id >= CDNS_UART_NR_PORTS) { + dev_err(&pdev->dev, "Cannot get uart_port structure\n"); + return -ENODEV; + } + + if (!cdns_uart_uart_driver.state) { + cdns_uart_uart_driver.owner = THIS_MODULE; + cdns_uart_uart_driver.driver_name = CDNS_UART_NAME; + cdns_uart_uart_driver.dev_name = CDNS_UART_TTY_NAME; + cdns_uart_uart_driver.major = CDNS_UART_MAJOR; + cdns_uart_uart_driver.minor = CDNS_UART_MINOR; + cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS; +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE + cdns_uart_uart_driver.cons = &cdns_uart_console; +#endif + + rc = uart_register_driver(&cdns_uart_uart_driver); + if (rc < 0) { + dev_err(&pdev->dev, "Failed to register driver\n"); + return rc; + } + } + + cdns_uart_data->cdns_uart_driver = &cdns_uart_uart_driver; + + match = of_match_node(cdns_uart_of_match, pdev->dev.of_node); + if (match && match->data) { + const struct cdns_platform_data *data = match->data; + + cdns_uart_data->quirks = data->quirks; + } + + cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "pclk"); + if (PTR_ERR(cdns_uart_data->pclk) == -EPROBE_DEFER) { + rc = PTR_ERR(cdns_uart_data->pclk); + goto err_out_unregister_driver; + } + + if (IS_ERR(cdns_uart_data->pclk)) { + cdns_uart_data->pclk = devm_clk_get(&pdev->dev, "aper_clk"); + if (IS_ERR(cdns_uart_data->pclk)) { + rc = PTR_ERR(cdns_uart_data->pclk); + goto err_out_unregister_driver; + } + dev_err(&pdev->dev, "clock name 'aper_clk' is deprecated.\n"); + } + + cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "uart_clk"); + if (PTR_ERR(cdns_uart_data->uartclk) == -EPROBE_DEFER) { + rc = PTR_ERR(cdns_uart_data->uartclk); + goto err_out_unregister_driver; + } + + if (IS_ERR(cdns_uart_data->uartclk)) { + cdns_uart_data->uartclk = devm_clk_get(&pdev->dev, "ref_clk"); + if (IS_ERR(cdns_uart_data->uartclk)) { + rc = PTR_ERR(cdns_uart_data->uartclk); + goto err_out_unregister_driver; + } + dev_err(&pdev->dev, "clock name 'ref_clk' is deprecated.\n"); + } + + rc = clk_prepare_enable(cdns_uart_data->pclk); + if (rc) { + dev_err(&pdev->dev, "Unable to enable pclk clock.\n"); + goto err_out_unregister_driver; + } + rc = clk_prepare_enable(cdns_uart_data->uartclk); + if (rc) { + dev_err(&pdev->dev, "Unable to enable device clock.\n"); + goto err_out_clk_dis_pclk; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + rc = -ENODEV; + goto err_out_clk_disable; + } + + irq = platform_get_irq(pdev, 0); + if (irq <= 0) { + rc = -ENXIO; + goto err_out_clk_disable; + } + +#ifdef CONFIG_COMMON_CLK + cdns_uart_data->clk_rate_change_nb.notifier_call = + cdns_uart_clk_notifier_cb; + if (clk_notifier_register(cdns_uart_data->uartclk, + &cdns_uart_data->clk_rate_change_nb)) + dev_warn(&pdev->dev, "Unable to register clock notifier.\n"); +#endif + + /* At this point, we've got an empty uart_port struct, initialize it */ + spin_lock_init(&port->lock); + port->type = PORT_UNKNOWN; + port->iotype = UPIO_MEM32; + port->flags = UPF_BOOT_AUTOCONF; + port->ops = &cdns_uart_ops; + port->fifosize = CDNS_UART_FIFO_SIZE; + port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE); + port->line = id; + + /* + * Register the port. + * This function also registers this device with the tty layer + * and triggers invocation of the config_port() entry point. + */ + port->mapbase = res->start; + port->irq = irq; + port->dev = &pdev->dev; + port->uartclk = clk_get_rate(cdns_uart_data->uartclk); + port->private_data = cdns_uart_data; + port->read_status_mask = CDNS_UART_IXR_TXEMPTY | CDNS_UART_IXR_RXTRIG | + CDNS_UART_IXR_OVERRUN | CDNS_UART_IXR_TOUT; + cdns_uart_data->port = port; + platform_set_drvdata(pdev, port); + + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + device_init_wakeup(port->dev, true); + +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE + /* + * If console hasn't been found yet try to assign this port + * because it is required to be assigned for console setup function. + * If register_console() don't assign value, then console_port pointer + * is cleanup. + */ + if (!console_port) { + cdns_uart_console.index = id; + console_port = port; + } +#endif + + rc = uart_add_one_port(&cdns_uart_uart_driver, port); + if (rc) { + dev_err(&pdev->dev, + "uart_add_one_port() failed; err=%i\n", rc); + goto err_out_pm_disable; + } + +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE + /* This is not port which is used for console that's why clean it up */ + if (console_port == port && + !(cdns_uart_uart_driver.cons->flags & CON_ENABLED)) { + console_port = NULL; + cdns_uart_console.index = -1; + } +#endif + + cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node, + "cts-override"); + + instances++; + + return 0; + +err_out_pm_disable: + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_dont_use_autosuspend(&pdev->dev); +#ifdef CONFIG_COMMON_CLK + clk_notifier_unregister(cdns_uart_data->uartclk, + &cdns_uart_data->clk_rate_change_nb); +#endif +err_out_clk_disable: + clk_disable_unprepare(cdns_uart_data->uartclk); +err_out_clk_dis_pclk: + clk_disable_unprepare(cdns_uart_data->pclk); +err_out_unregister_driver: + if (!instances) + uart_unregister_driver(cdns_uart_data->cdns_uart_driver); + return rc; +} + +/** + * cdns_uart_remove - called when the platform driver is unregistered + * @pdev: Pointer to the platform device structure + * + * Return: 0 on success, negative errno otherwise + */ +static int cdns_uart_remove(struct platform_device *pdev) +{ + struct uart_port *port = platform_get_drvdata(pdev); + struct cdns_uart *cdns_uart_data = port->private_data; + int rc; + + /* Remove the cdns_uart port from the serial core */ +#ifdef CONFIG_COMMON_CLK + clk_notifier_unregister(cdns_uart_data->uartclk, + &cdns_uart_data->clk_rate_change_nb); +#endif + rc = uart_remove_one_port(cdns_uart_data->cdns_uart_driver, port); + port->mapbase = 0; + clk_disable_unprepare(cdns_uart_data->uartclk); + clk_disable_unprepare(cdns_uart_data->pclk); + pm_runtime_disable(&pdev->dev); + pm_runtime_set_suspended(&pdev->dev); + pm_runtime_dont_use_autosuspend(&pdev->dev); + device_init_wakeup(&pdev->dev, false); + +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE + if (console_port == port) + console_port = NULL; +#endif + + if (!--instances) + uart_unregister_driver(cdns_uart_data->cdns_uart_driver); + return rc; +} + +static struct platform_driver cdns_uart_platform_driver = { + .probe = cdns_uart_probe, + .remove = cdns_uart_remove, + .driver = { + .name = CDNS_UART_NAME, + .of_match_table = cdns_uart_of_match, + .pm = &cdns_uart_dev_pm_ops, + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_XILINX_PS_UART), + }, +}; + +static int __init cdns_uart_init(void) +{ + /* Register the platform driver */ + return platform_driver_register(&cdns_uart_platform_driver); +} + +static void __exit cdns_uart_exit(void) +{ + /* Unregister the platform driver */ + platform_driver_unregister(&cdns_uart_platform_driver); +} + +arch_initcall(cdns_uart_init); +module_exit(cdns_uart_exit); + +MODULE_DESCRIPTION("Driver for Cadence UART"); +MODULE_AUTHOR("Xilinx Inc."); +MODULE_LICENSE("GPL"); |