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linux/linux-5.4.31/drivers/tty/serial/xilinx_uartps.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Cadence UART driver (found in Xilinx Zynq)
*
* 2011 - 2014 (C) 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.
*/
#if defined(CONFIG_SERIAL_XILINX_PS_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#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_FIFO_SIZE 64 /* FIFO size */
#define CDNS_UART_REGISTER_SPACE 0x1000
#define TX_TIMEOUT 500000
/* Rx Trigger level */
static int rx_trigger_level = 56;
static int uartps_major;
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 */
/*
* 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
* @id: Port ID
* @clk_rate_change_nb: Notifier block for clock changes
* @quirks: Flags for RXBS support.
*/
struct cdns_uart {
struct uart_port *port;
struct clk *uartclk;
struct clk *pclk;
struct uart_driver *cdns_uart_driver;
unsigned int baud;
int id;
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;
}
spin_unlock(&port->lock);
tty_flip_buffer_push(&port->state->port);
spin_lock(&port->lock);
}
/**
* 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;
unsigned int numbytes;
if (uart_circ_empty(&port->state->xmit)) {
writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_IDR);
} else {
numbytes = port->fifosize;
while (numbytes && !uart_circ_empty(&port->state->xmit) &&
!(readl(port->membase + CDNS_UART_SR) &
CDNS_UART_SR_TXFULL)) {
/*
* Get the data from the UART circular buffer
* and write it to the cdns_uart's TX_FIFO
* register.
*/
writel(
port->state->xmit.buf[port->state->xmit.tail],
port->membase + CDNS_UART_FIFO);
port->icount.tx++;
/*
* Adjust the tail of the UART buffer and wrap
* the buffer if it reaches limit.
*/
port->state->xmit.tail =
(port->state->xmit.tail + 1) &
(UART_XMIT_SIZE - 1);
numbytes--;
}
if (uart_circ_chars_pending(
&port->state->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;
}
/*
* 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_notitifer_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;
unsigned long flags = 0;
struct cdns_uart *cdns_uart = to_cdns_uart(nb);
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);
/* fall through */
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;
cdns_uart_handle_tx(port);
writel(CDNS_UART_IXR_TXEMPTY, port->membase + CDNS_UART_ISR);
/* 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;
return status ? 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, struct ktermios *old)
{
unsigned int cval = 0;
unsigned int baud, minbaud, maxbaud;
unsigned long flags;
unsigned int ctrl_reg, mode_reg, val;
int err;
/* Wait for the transmit FIFO to empty before making changes */
if (!(readl(port->membase + CDNS_UART_CR) &
CDNS_UART_CR_TX_DIS)) {
err = readl_poll_timeout(port->membase + CDNS_UART_SR,
val, (val & CDNS_UART_SR_TXEMPTY),
1000, TX_TIMEOUT);
if (err) {
dev_err(port->dev, "timed out waiting for tx empty");
return;
}
}
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);
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)
{
struct cdns_uart *cdns_uart_data = port->private_data;
if (cdns_uart_data->cts_override)
return 0;
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
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 |
CDNS_UART_MODEMCR_FCM);
mode_reg &= ~CDNS_UART_MR_CHMODE_MASK;
if (mctrl & TIOCM_RTS || mctrl & TIOCM_DTR)
val |= CDNS_UART_MODEMCR_FCM;
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
};
#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, int ch)
{
while (readl(port->membase + CDNS_UART_SR) & CDNS_UART_SR_TXFULL)
cpu_relax();
writel(ch, port->membase + CDNS_UART_FIFO);
}
static void cdns_early_write(struct console *con, const char *s,
unsigned 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 = 0;
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 ((readl(port->membase + CDNS_UART_SR) &
(CDNS_UART_SR_TXEMPTY | CDNS_UART_SR_TACTIVE)) !=
CDNS_UART_SR_TXEMPTY)
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';
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);
return uart_set_options(port, co, baud, parity, bits, flow);
}
#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 = 0;
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 = 0;
u32 ctrl_reg;
int may_wake;
may_wake = device_may_wakeup(device);
if (console_suspend_enabled && uart_console(port) && !may_wake) {
clk_enable(cdns_uart->pclk);
clk_enable(cdns_uart->uartclk);
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;
clk_enable(cdns_uart->pclk);
clk_enable(cdns_uart->uartclk);
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);
/*
* Maximum number of instances without alias IDs but if there is alias
* which target "< MAX_UART_INSTANCES" range this ID can't be used.
*/
#define MAX_UART_INSTANCES 32
/* Stores static aliases list */
static DECLARE_BITMAP(alias_bitmap, MAX_UART_INSTANCES);
static int alias_bitmap_initialized;
/* Stores actual bitmap of allocated IDs with alias IDs together */
static DECLARE_BITMAP(bitmap, MAX_UART_INSTANCES);
/* Protect bitmap operations to have unique IDs */
static DEFINE_MUTEX(bitmap_lock);
static int cdns_get_id(struct platform_device *pdev)
{
int id, ret;
mutex_lock(&bitmap_lock);
/* Alias list is stable that's why get alias bitmap only once */
if (!alias_bitmap_initialized) {
ret = of_alias_get_alias_list(cdns_uart_of_match, "serial",
alias_bitmap, MAX_UART_INSTANCES);
if (ret && ret != -EOVERFLOW) {
mutex_unlock(&bitmap_lock);
return ret;
}
alias_bitmap_initialized++;
}
/* Make sure that alias ID is not taken by instance without alias */
bitmap_or(bitmap, bitmap, alias_bitmap, MAX_UART_INSTANCES);
dev_dbg(&pdev->dev, "Alias bitmap: %*pb\n",
MAX_UART_INSTANCES, bitmap);
/* Look for a serialN alias */
id = of_alias_get_id(pdev->dev.of_node, "serial");
if (id < 0) {
dev_warn(&pdev->dev,
"No serial alias passed. Using the first free id\n");
/*
* Start with id 0 and check if there is no serial0 alias
* which points to device which is compatible with this driver.
* If alias exists then try next free position.
*/
id = 0;
for (;;) {
dev_info(&pdev->dev, "Checking id %d\n", id);
id = find_next_zero_bit(bitmap, MAX_UART_INSTANCES, id);
/* No free empty instance */
if (id == MAX_UART_INSTANCES) {
dev_err(&pdev->dev, "No free ID\n");
mutex_unlock(&bitmap_lock);
return -EINVAL;
}
dev_dbg(&pdev->dev, "The empty id is %d\n", id);
/* Check if ID is empty */
if (!test_and_set_bit(id, bitmap)) {
/* Break the loop if bit is taken */
dev_dbg(&pdev->dev,
"Selected ID %d allocation passed\n",
id);
break;
}
dev_dbg(&pdev->dev,
"Selected ID %d allocation failed\n", id);
/* if taking bit fails then try next one */
id++;
}
}
mutex_unlock(&bitmap_lock);
return id;
}
/**
* 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, irq;
struct uart_port *port;
struct resource *res;
struct cdns_uart *cdns_uart_data;
const struct of_device_id *match;
struct uart_driver *cdns_uart_uart_driver;
char *driver_name;
#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
struct console *cdns_uart_console;
#endif
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;
cdns_uart_uart_driver = devm_kzalloc(&pdev->dev,
sizeof(*cdns_uart_uart_driver),
GFP_KERNEL);
if (!cdns_uart_uart_driver)
return -ENOMEM;
cdns_uart_data->id = cdns_get_id(pdev);
if (cdns_uart_data->id < 0)
return cdns_uart_data->id;
/* There is a need to use unique driver name */
driver_name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%s%d",
CDNS_UART_NAME, cdns_uart_data->id);
if (!driver_name) {
rc = -ENOMEM;
goto err_out_id;
}
cdns_uart_uart_driver->owner = THIS_MODULE;
cdns_uart_uart_driver->driver_name = driver_name;
cdns_uart_uart_driver->dev_name = CDNS_UART_TTY_NAME;
cdns_uart_uart_driver->major = uartps_major;
cdns_uart_uart_driver->minor = cdns_uart_data->id;
cdns_uart_uart_driver->nr = 1;
#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
cdns_uart_console = devm_kzalloc(&pdev->dev, sizeof(*cdns_uart_console),
GFP_KERNEL);
if (!cdns_uart_console) {
rc = -ENOMEM;
goto err_out_id;
}
strncpy(cdns_uart_console->name, CDNS_UART_TTY_NAME,
sizeof(cdns_uart_console->name));
cdns_uart_console->index = cdns_uart_data->id;
cdns_uart_console->write = cdns_uart_console_write;
cdns_uart_console->device = uart_console_device;
cdns_uart_console->setup = cdns_uart_console_setup;
cdns_uart_console->flags = CON_PRINTBUFFER;
cdns_uart_console->data = cdns_uart_uart_driver;
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");
goto err_out_id;
}
cdns_uart_data->cdns_uart_driver = cdns_uart_uart_driver;
/*
* Setting up proper name_base needs to be done after uart
* registration because tty_driver structure is not filled.
* name_base is 0 by default.
*/
cdns_uart_uart_driver->tty_driver->name_base = cdns_uart_data->id;
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;
/*
* 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;
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)
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;
#endif
uartps_major = cdns_uart_uart_driver->tty_driver->major;
cdns_uart_data->cts_override = of_property_read_bool(pdev->dev.of_node,
"cts-override");
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:
uart_unregister_driver(cdns_uart_data->cdns_uart_driver);
err_out_id:
mutex_lock(&bitmap_lock);
if (cdns_uart_data->id < MAX_UART_INSTANCES)
clear_bit(cdns_uart_data->id, bitmap);
mutex_unlock(&bitmap_lock);
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;
mutex_lock(&bitmap_lock);
if (cdns_uart_data->id < MAX_UART_INSTANCES)
clear_bit(cdns_uart_data->id, bitmap);
mutex_unlock(&bitmap_lock);
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 this is last instance major number should be initialized */
mutex_lock(&bitmap_lock);
if (bitmap_empty(bitmap, MAX_UART_INSTANCES))
uartps_major = 0;
mutex_unlock(&bitmap_lock);
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");
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