linux/drivers/tty/serial/mxs-auart.c
Hector Palacios 9987f76ad2 serial: mxs-auart: set the FIFO size to DMA buffer size
When DMA is enabled (with hardware flow control enabled) the FIFO size
must be set to the size of the DMA buffer, as this is the size the tty
subsystem can use.

Signed-off-by: Hector Palacios <hector.palacios@digi.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-05 18:03:01 -07:00

1162 lines
28 KiB
C

/*
* Freescale STMP37XX/STMP378X Application UART driver
*
* Author: dmitry pervushin <dimka@embeddedalley.com>
*
* Copyright 2008-2010 Freescale Semiconductor, Inc.
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/wait.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of_device.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <asm/cacheflush.h>
#define MXS_AUART_PORTS 5
#define MXS_AUART_FIFO_SIZE 16
#define AUART_CTRL0 0x00000000
#define AUART_CTRL0_SET 0x00000004
#define AUART_CTRL0_CLR 0x00000008
#define AUART_CTRL0_TOG 0x0000000c
#define AUART_CTRL1 0x00000010
#define AUART_CTRL1_SET 0x00000014
#define AUART_CTRL1_CLR 0x00000018
#define AUART_CTRL1_TOG 0x0000001c
#define AUART_CTRL2 0x00000020
#define AUART_CTRL2_SET 0x00000024
#define AUART_CTRL2_CLR 0x00000028
#define AUART_CTRL2_TOG 0x0000002c
#define AUART_LINECTRL 0x00000030
#define AUART_LINECTRL_SET 0x00000034
#define AUART_LINECTRL_CLR 0x00000038
#define AUART_LINECTRL_TOG 0x0000003c
#define AUART_LINECTRL2 0x00000040
#define AUART_LINECTRL2_SET 0x00000044
#define AUART_LINECTRL2_CLR 0x00000048
#define AUART_LINECTRL2_TOG 0x0000004c
#define AUART_INTR 0x00000050
#define AUART_INTR_SET 0x00000054
#define AUART_INTR_CLR 0x00000058
#define AUART_INTR_TOG 0x0000005c
#define AUART_DATA 0x00000060
#define AUART_STAT 0x00000070
#define AUART_DEBUG 0x00000080
#define AUART_VERSION 0x00000090
#define AUART_AUTOBAUD 0x000000a0
#define AUART_CTRL0_SFTRST (1 << 31)
#define AUART_CTRL0_CLKGATE (1 << 30)
#define AUART_CTRL0_RXTO_ENABLE (1 << 27)
#define AUART_CTRL0_RXTIMEOUT(v) (((v) & 0x7ff) << 16)
#define AUART_CTRL0_XFER_COUNT(v) ((v) & 0xffff)
#define AUART_CTRL1_XFER_COUNT(v) ((v) & 0xffff)
#define AUART_CTRL2_DMAONERR (1 << 26)
#define AUART_CTRL2_TXDMAE (1 << 25)
#define AUART_CTRL2_RXDMAE (1 << 24)
#define AUART_CTRL2_CTSEN (1 << 15)
#define AUART_CTRL2_RTSEN (1 << 14)
#define AUART_CTRL2_RTS (1 << 11)
#define AUART_CTRL2_RXE (1 << 9)
#define AUART_CTRL2_TXE (1 << 8)
#define AUART_CTRL2_UARTEN (1 << 0)
#define AUART_LINECTRL_BAUD_DIVINT_SHIFT 16
#define AUART_LINECTRL_BAUD_DIVINT_MASK 0xffff0000
#define AUART_LINECTRL_BAUD_DIVINT(v) (((v) & 0xffff) << 16)
#define AUART_LINECTRL_BAUD_DIVFRAC_SHIFT 8
#define AUART_LINECTRL_BAUD_DIVFRAC_MASK 0x00003f00
#define AUART_LINECTRL_BAUD_DIVFRAC(v) (((v) & 0x3f) << 8)
#define AUART_LINECTRL_WLEN_MASK 0x00000060
#define AUART_LINECTRL_WLEN(v) (((v) & 0x3) << 5)
#define AUART_LINECTRL_FEN (1 << 4)
#define AUART_LINECTRL_STP2 (1 << 3)
#define AUART_LINECTRL_EPS (1 << 2)
#define AUART_LINECTRL_PEN (1 << 1)
#define AUART_LINECTRL_BRK (1 << 0)
#define AUART_INTR_RTIEN (1 << 22)
#define AUART_INTR_TXIEN (1 << 21)
#define AUART_INTR_RXIEN (1 << 20)
#define AUART_INTR_CTSMIEN (1 << 17)
#define AUART_INTR_RTIS (1 << 6)
#define AUART_INTR_TXIS (1 << 5)
#define AUART_INTR_RXIS (1 << 4)
#define AUART_INTR_CTSMIS (1 << 1)
#define AUART_STAT_BUSY (1 << 29)
#define AUART_STAT_CTS (1 << 28)
#define AUART_STAT_TXFE (1 << 27)
#define AUART_STAT_TXFF (1 << 25)
#define AUART_STAT_RXFE (1 << 24)
#define AUART_STAT_OERR (1 << 19)
#define AUART_STAT_BERR (1 << 18)
#define AUART_STAT_PERR (1 << 17)
#define AUART_STAT_FERR (1 << 16)
#define AUART_STAT_RXCOUNT_MASK 0xffff
static struct uart_driver auart_driver;
enum mxs_auart_type {
IMX23_AUART,
IMX28_AUART,
};
struct mxs_auart_port {
struct uart_port port;
#define MXS_AUART_DMA_ENABLED 0x2
#define MXS_AUART_DMA_TX_SYNC 2 /* bit 2 */
#define MXS_AUART_DMA_RX_READY 3 /* bit 3 */
#define MXS_AUART_RTSCTS 4 /* bit 4 */
unsigned long flags;
unsigned int ctrl;
enum mxs_auart_type devtype;
unsigned int irq;
struct clk *clk;
struct device *dev;
/* for DMA */
struct scatterlist tx_sgl;
struct dma_chan *tx_dma_chan;
void *tx_dma_buf;
struct scatterlist rx_sgl;
struct dma_chan *rx_dma_chan;
void *rx_dma_buf;
};
static struct platform_device_id mxs_auart_devtype[] = {
{ .name = "mxs-auart-imx23", .driver_data = IMX23_AUART },
{ .name = "mxs-auart-imx28", .driver_data = IMX28_AUART },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, mxs_auart_devtype);
static struct of_device_id mxs_auart_dt_ids[] = {
{
.compatible = "fsl,imx28-auart",
.data = &mxs_auart_devtype[IMX28_AUART]
}, {
.compatible = "fsl,imx23-auart",
.data = &mxs_auart_devtype[IMX23_AUART]
}, { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_auart_dt_ids);
static inline int is_imx28_auart(struct mxs_auart_port *s)
{
return s->devtype == IMX28_AUART;
}
static inline bool auart_dma_enabled(struct mxs_auart_port *s)
{
return s->flags & MXS_AUART_DMA_ENABLED;
}
static void mxs_auart_stop_tx(struct uart_port *u);
#define to_auart_port(u) container_of(u, struct mxs_auart_port, port)
static void mxs_auart_tx_chars(struct mxs_auart_port *s);
static void dma_tx_callback(void *param)
{
struct mxs_auart_port *s = param;
struct circ_buf *xmit = &s->port.state->xmit;
dma_unmap_sg(s->dev, &s->tx_sgl, 1, DMA_TO_DEVICE);
/* clear the bit used to serialize the DMA tx. */
clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
smp_mb__after_clear_bit();
/* wake up the possible processes. */
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&s->port);
mxs_auart_tx_chars(s);
}
static int mxs_auart_dma_tx(struct mxs_auart_port *s, int size)
{
struct dma_async_tx_descriptor *desc;
struct scatterlist *sgl = &s->tx_sgl;
struct dma_chan *channel = s->tx_dma_chan;
u32 pio;
/* [1] : send PIO. Note, the first pio word is CTRL1. */
pio = AUART_CTRL1_XFER_COUNT(size);
desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)&pio,
1, DMA_TRANS_NONE, 0);
if (!desc) {
dev_err(s->dev, "step 1 error\n");
return -EINVAL;
}
/* [2] : set DMA buffer. */
sg_init_one(sgl, s->tx_dma_buf, size);
dma_map_sg(s->dev, sgl, 1, DMA_TO_DEVICE);
desc = dmaengine_prep_slave_sg(channel, sgl,
1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dev_err(s->dev, "step 2 error\n");
return -EINVAL;
}
/* [3] : submit the DMA */
desc->callback = dma_tx_callback;
desc->callback_param = s;
dmaengine_submit(desc);
dma_async_issue_pending(channel);
return 0;
}
static void mxs_auart_tx_chars(struct mxs_auart_port *s)
{
struct circ_buf *xmit = &s->port.state->xmit;
if (auart_dma_enabled(s)) {
u32 i = 0;
int size;
void *buffer = s->tx_dma_buf;
if (test_and_set_bit(MXS_AUART_DMA_TX_SYNC, &s->flags))
return;
while (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) {
size = min_t(u32, UART_XMIT_SIZE - i,
CIRC_CNT_TO_END(xmit->head,
xmit->tail,
UART_XMIT_SIZE));
memcpy(buffer + i, xmit->buf + xmit->tail, size);
xmit->tail = (xmit->tail + size) & (UART_XMIT_SIZE - 1);
i += size;
if (i >= UART_XMIT_SIZE)
break;
}
if (uart_tx_stopped(&s->port))
mxs_auart_stop_tx(&s->port);
if (i) {
mxs_auart_dma_tx(s, i);
} else {
clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
smp_mb__after_clear_bit();
}
return;
}
while (!(readl(s->port.membase + AUART_STAT) &
AUART_STAT_TXFF)) {
if (s->port.x_char) {
s->port.icount.tx++;
writel(s->port.x_char,
s->port.membase + AUART_DATA);
s->port.x_char = 0;
continue;
}
if (!uart_circ_empty(xmit) && !uart_tx_stopped(&s->port)) {
s->port.icount.tx++;
writel(xmit->buf[xmit->tail],
s->port.membase + AUART_DATA);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
} else
break;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&s->port);
if (uart_circ_empty(&(s->port.state->xmit)))
writel(AUART_INTR_TXIEN,
s->port.membase + AUART_INTR_CLR);
else
writel(AUART_INTR_TXIEN,
s->port.membase + AUART_INTR_SET);
if (uart_tx_stopped(&s->port))
mxs_auart_stop_tx(&s->port);
}
static void mxs_auart_rx_char(struct mxs_auart_port *s)
{
int flag;
u32 stat;
u8 c;
c = readl(s->port.membase + AUART_DATA);
stat = readl(s->port.membase + AUART_STAT);
flag = TTY_NORMAL;
s->port.icount.rx++;
if (stat & AUART_STAT_BERR) {
s->port.icount.brk++;
if (uart_handle_break(&s->port))
goto out;
} else if (stat & AUART_STAT_PERR) {
s->port.icount.parity++;
} else if (stat & AUART_STAT_FERR) {
s->port.icount.frame++;
}
/*
* Mask off conditions which should be ingored.
*/
stat &= s->port.read_status_mask;
if (stat & AUART_STAT_BERR) {
flag = TTY_BREAK;
} else if (stat & AUART_STAT_PERR)
flag = TTY_PARITY;
else if (stat & AUART_STAT_FERR)
flag = TTY_FRAME;
if (stat & AUART_STAT_OERR)
s->port.icount.overrun++;
if (uart_handle_sysrq_char(&s->port, c))
goto out;
uart_insert_char(&s->port, stat, AUART_STAT_OERR, c, flag);
out:
writel(stat, s->port.membase + AUART_STAT);
}
static void mxs_auart_rx_chars(struct mxs_auart_port *s)
{
u32 stat = 0;
for (;;) {
stat = readl(s->port.membase + AUART_STAT);
if (stat & AUART_STAT_RXFE)
break;
mxs_auart_rx_char(s);
}
writel(stat, s->port.membase + AUART_STAT);
tty_flip_buffer_push(&s->port.state->port);
}
static int mxs_auart_request_port(struct uart_port *u)
{
return 0;
}
static int mxs_auart_verify_port(struct uart_port *u,
struct serial_struct *ser)
{
if (u->type != PORT_UNKNOWN && u->type != PORT_IMX)
return -EINVAL;
return 0;
}
static void mxs_auart_config_port(struct uart_port *u, int flags)
{
}
static const char *mxs_auart_type(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
return dev_name(s->dev);
}
static void mxs_auart_release_port(struct uart_port *u)
{
}
static void mxs_auart_set_mctrl(struct uart_port *u, unsigned mctrl)
{
struct mxs_auart_port *s = to_auart_port(u);
u32 ctrl = readl(u->membase + AUART_CTRL2);
ctrl &= ~(AUART_CTRL2_RTSEN | AUART_CTRL2_RTS);
if (mctrl & TIOCM_RTS) {
if (tty_port_cts_enabled(&u->state->port))
ctrl |= AUART_CTRL2_RTSEN;
else
ctrl |= AUART_CTRL2_RTS;
}
s->ctrl = mctrl;
writel(ctrl, u->membase + AUART_CTRL2);
}
static u32 mxs_auart_get_mctrl(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
u32 stat = readl(u->membase + AUART_STAT);
int ctrl2 = readl(u->membase + AUART_CTRL2);
u32 mctrl = s->ctrl;
mctrl &= ~TIOCM_CTS;
if (stat & AUART_STAT_CTS)
mctrl |= TIOCM_CTS;
if (ctrl2 & AUART_CTRL2_RTS)
mctrl |= TIOCM_RTS;
return mctrl;
}
static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s);
static void dma_rx_callback(void *arg)
{
struct mxs_auart_port *s = (struct mxs_auart_port *) arg;
struct tty_port *port = &s->port.state->port;
int count;
u32 stat;
dma_unmap_sg(s->dev, &s->rx_sgl, 1, DMA_FROM_DEVICE);
stat = readl(s->port.membase + AUART_STAT);
stat &= ~(AUART_STAT_OERR | AUART_STAT_BERR |
AUART_STAT_PERR | AUART_STAT_FERR);
count = stat & AUART_STAT_RXCOUNT_MASK;
tty_insert_flip_string(port, s->rx_dma_buf, count);
writel(stat, s->port.membase + AUART_STAT);
tty_flip_buffer_push(port);
/* start the next DMA for RX. */
mxs_auart_dma_prep_rx(s);
}
static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s)
{
struct dma_async_tx_descriptor *desc;
struct scatterlist *sgl = &s->rx_sgl;
struct dma_chan *channel = s->rx_dma_chan;
u32 pio[1];
/* [1] : send PIO */
pio[0] = AUART_CTRL0_RXTO_ENABLE
| AUART_CTRL0_RXTIMEOUT(0x80)
| AUART_CTRL0_XFER_COUNT(UART_XMIT_SIZE);
desc = dmaengine_prep_slave_sg(channel, (struct scatterlist *)pio,
1, DMA_TRANS_NONE, 0);
if (!desc) {
dev_err(s->dev, "step 1 error\n");
return -EINVAL;
}
/* [2] : send DMA request */
sg_init_one(sgl, s->rx_dma_buf, UART_XMIT_SIZE);
dma_map_sg(s->dev, sgl, 1, DMA_FROM_DEVICE);
desc = dmaengine_prep_slave_sg(channel, sgl, 1, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dev_err(s->dev, "step 2 error\n");
return -1;
}
/* [3] : submit the DMA, but do not issue it. */
desc->callback = dma_rx_callback;
desc->callback_param = s;
dmaengine_submit(desc);
dma_async_issue_pending(channel);
return 0;
}
static void mxs_auart_dma_exit_channel(struct mxs_auart_port *s)
{
if (s->tx_dma_chan) {
dma_release_channel(s->tx_dma_chan);
s->tx_dma_chan = NULL;
}
if (s->rx_dma_chan) {
dma_release_channel(s->rx_dma_chan);
s->rx_dma_chan = NULL;
}
kfree(s->tx_dma_buf);
kfree(s->rx_dma_buf);
s->tx_dma_buf = NULL;
s->rx_dma_buf = NULL;
}
static void mxs_auart_dma_exit(struct mxs_auart_port *s)
{
writel(AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE | AUART_CTRL2_DMAONERR,
s->port.membase + AUART_CTRL2_CLR);
mxs_auart_dma_exit_channel(s);
s->flags &= ~MXS_AUART_DMA_ENABLED;
clear_bit(MXS_AUART_DMA_TX_SYNC, &s->flags);
clear_bit(MXS_AUART_DMA_RX_READY, &s->flags);
}
static int mxs_auart_dma_init(struct mxs_auart_port *s)
{
if (auart_dma_enabled(s))
return 0;
/* init for RX */
s->rx_dma_chan = dma_request_slave_channel(s->dev, "rx");
if (!s->rx_dma_chan)
goto err_out;
s->rx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
if (!s->rx_dma_buf)
goto err_out;
/* init for TX */
s->tx_dma_chan = dma_request_slave_channel(s->dev, "tx");
if (!s->tx_dma_chan)
goto err_out;
s->tx_dma_buf = kzalloc(UART_XMIT_SIZE, GFP_KERNEL | GFP_DMA);
if (!s->tx_dma_buf)
goto err_out;
/* set the flags */
s->flags |= MXS_AUART_DMA_ENABLED;
dev_dbg(s->dev, "enabled the DMA support.");
/* The DMA buffer is now the FIFO the TTY subsystem can use */
s->port.fifosize = UART_XMIT_SIZE;
return 0;
err_out:
mxs_auart_dma_exit_channel(s);
return -EINVAL;
}
static void mxs_auart_settermios(struct uart_port *u,
struct ktermios *termios,
struct ktermios *old)
{
struct mxs_auart_port *s = to_auart_port(u);
u32 bm, ctrl, ctrl2, div;
unsigned int cflag, baud;
cflag = termios->c_cflag;
ctrl = AUART_LINECTRL_FEN;
ctrl2 = readl(u->membase + AUART_CTRL2);
/* byte size */
switch (cflag & CSIZE) {
case CS5:
bm = 0;
break;
case CS6:
bm = 1;
break;
case CS7:
bm = 2;
break;
case CS8:
bm = 3;
break;
default:
return;
}
ctrl |= AUART_LINECTRL_WLEN(bm);
/* parity */
if (cflag & PARENB) {
ctrl |= AUART_LINECTRL_PEN;
if ((cflag & PARODD) == 0)
ctrl |= AUART_LINECTRL_EPS;
}
u->read_status_mask = 0;
if (termios->c_iflag & INPCK)
u->read_status_mask |= AUART_STAT_PERR;
if (termios->c_iflag & (BRKINT | PARMRK))
u->read_status_mask |= AUART_STAT_BERR;
/*
* Characters to ignore
*/
u->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
u->ignore_status_mask |= AUART_STAT_PERR;
if (termios->c_iflag & IGNBRK) {
u->ignore_status_mask |= AUART_STAT_BERR;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
u->ignore_status_mask |= AUART_STAT_OERR;
}
/*
* ignore all characters if CREAD is not set
*/
if (cflag & CREAD)
ctrl2 |= AUART_CTRL2_RXE;
else
ctrl2 &= ~AUART_CTRL2_RXE;
/* figure out the stop bits requested */
if (cflag & CSTOPB)
ctrl |= AUART_LINECTRL_STP2;
/* figure out the hardware flow control settings */
if (cflag & CRTSCTS) {
/*
* The DMA has a bug(see errata:2836) in mx23.
* So we can not implement the DMA for auart in mx23,
* we can only implement the DMA support for auart
* in mx28.
*/
if (is_imx28_auart(s)
&& test_bit(MXS_AUART_RTSCTS, &s->flags)) {
if (!mxs_auart_dma_init(s))
/* enable DMA tranfer */
ctrl2 |= AUART_CTRL2_TXDMAE | AUART_CTRL2_RXDMAE
| AUART_CTRL2_DMAONERR;
}
ctrl2 |= AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN;
} else {
ctrl2 &= ~(AUART_CTRL2_CTSEN | AUART_CTRL2_RTSEN);
}
/* set baud rate */
baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk);
div = u->uartclk * 32 / baud;
ctrl |= AUART_LINECTRL_BAUD_DIVFRAC(div & 0x3F);
ctrl |= AUART_LINECTRL_BAUD_DIVINT(div >> 6);
writel(ctrl, u->membase + AUART_LINECTRL);
writel(ctrl2, u->membase + AUART_CTRL2);
uart_update_timeout(u, termios->c_cflag, baud);
/* prepare for the DMA RX. */
if (auart_dma_enabled(s) &&
!test_and_set_bit(MXS_AUART_DMA_RX_READY, &s->flags)) {
if (!mxs_auart_dma_prep_rx(s)) {
/* Disable the normal RX interrupt. */
writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN,
u->membase + AUART_INTR_CLR);
} else {
mxs_auart_dma_exit(s);
dev_err(s->dev, "We can not start up the DMA.\n");
}
}
}
static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
{
u32 istat;
struct mxs_auart_port *s = context;
u32 stat = readl(s->port.membase + AUART_STAT);
istat = readl(s->port.membase + AUART_INTR);
/* ack irq */
writel(istat & (AUART_INTR_RTIS
| AUART_INTR_TXIS
| AUART_INTR_RXIS
| AUART_INTR_CTSMIS),
s->port.membase + AUART_INTR_CLR);
if (istat & AUART_INTR_CTSMIS) {
uart_handle_cts_change(&s->port, stat & AUART_STAT_CTS);
writel(AUART_INTR_CTSMIS,
s->port.membase + AUART_INTR_CLR);
istat &= ~AUART_INTR_CTSMIS;
}
if (istat & (AUART_INTR_RTIS | AUART_INTR_RXIS)) {
if (!auart_dma_enabled(s))
mxs_auart_rx_chars(s);
istat &= ~(AUART_INTR_RTIS | AUART_INTR_RXIS);
}
if (istat & AUART_INTR_TXIS) {
mxs_auart_tx_chars(s);
istat &= ~AUART_INTR_TXIS;
}
return IRQ_HANDLED;
}
static void mxs_auart_reset(struct uart_port *u)
{
int i;
unsigned int reg;
writel(AUART_CTRL0_SFTRST, u->membase + AUART_CTRL0_CLR);
for (i = 0; i < 10000; i++) {
reg = readl(u->membase + AUART_CTRL0);
if (!(reg & AUART_CTRL0_SFTRST))
break;
udelay(3);
}
writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
}
static int mxs_auart_startup(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
clk_prepare_enable(s->clk);
writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_CLR);
writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_SET);
writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
u->membase + AUART_INTR);
/* Reset FIFO size (it could have changed if DMA was enabled) */
u->fifosize = MXS_AUART_FIFO_SIZE;
/*
* Enable fifo so all four bytes of a DMA word are written to
* output (otherwise, only the LSB is written, ie. 1 in 4 bytes)
*/
writel(AUART_LINECTRL_FEN, u->membase + AUART_LINECTRL_SET);
return 0;
}
static void mxs_auart_shutdown(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
if (auart_dma_enabled(s))
mxs_auart_dma_exit(s);
writel(AUART_CTRL2_UARTEN, u->membase + AUART_CTRL2_CLR);
writel(AUART_INTR_RXIEN | AUART_INTR_RTIEN | AUART_INTR_CTSMIEN,
u->membase + AUART_INTR_CLR);
writel(AUART_CTRL0_CLKGATE, u->membase + AUART_CTRL0_SET);
clk_disable_unprepare(s->clk);
}
static unsigned int mxs_auart_tx_empty(struct uart_port *u)
{
if (readl(u->membase + AUART_STAT) & AUART_STAT_TXFE)
return TIOCSER_TEMT;
else
return 0;
}
static void mxs_auart_start_tx(struct uart_port *u)
{
struct mxs_auart_port *s = to_auart_port(u);
/* enable transmitter */
writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_SET);
mxs_auart_tx_chars(s);
}
static void mxs_auart_stop_tx(struct uart_port *u)
{
writel(AUART_CTRL2_TXE, u->membase + AUART_CTRL2_CLR);
}
static void mxs_auart_stop_rx(struct uart_port *u)
{
writel(AUART_CTRL2_RXE, u->membase + AUART_CTRL2_CLR);
}
static void mxs_auart_break_ctl(struct uart_port *u, int ctl)
{
if (ctl)
writel(AUART_LINECTRL_BRK,
u->membase + AUART_LINECTRL_SET);
else
writel(AUART_LINECTRL_BRK,
u->membase + AUART_LINECTRL_CLR);
}
static void mxs_auart_enable_ms(struct uart_port *port)
{
/* just empty */
}
static struct uart_ops mxs_auart_ops = {
.tx_empty = mxs_auart_tx_empty,
.start_tx = mxs_auart_start_tx,
.stop_tx = mxs_auart_stop_tx,
.stop_rx = mxs_auart_stop_rx,
.enable_ms = mxs_auart_enable_ms,
.break_ctl = mxs_auart_break_ctl,
.set_mctrl = mxs_auart_set_mctrl,
.get_mctrl = mxs_auart_get_mctrl,
.startup = mxs_auart_startup,
.shutdown = mxs_auart_shutdown,
.set_termios = mxs_auart_settermios,
.type = mxs_auart_type,
.release_port = mxs_auart_release_port,
.request_port = mxs_auart_request_port,
.config_port = mxs_auart_config_port,
.verify_port = mxs_auart_verify_port,
};
static struct mxs_auart_port *auart_port[MXS_AUART_PORTS];
#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
static void mxs_auart_console_putchar(struct uart_port *port, int ch)
{
unsigned int to = 1000;
while (readl(port->membase + AUART_STAT) & AUART_STAT_TXFF) {
if (!to--)
break;
udelay(1);
}
writel(ch, port->membase + AUART_DATA);
}
static void
auart_console_write(struct console *co, const char *str, unsigned int count)
{
struct mxs_auart_port *s;
struct uart_port *port;
unsigned int old_ctrl0, old_ctrl2;
unsigned int to = 20000;
if (co->index >= MXS_AUART_PORTS || co->index < 0)
return;
s = auart_port[co->index];
port = &s->port;
clk_enable(s->clk);
/* First save the CR then disable the interrupts */
old_ctrl2 = readl(port->membase + AUART_CTRL2);
old_ctrl0 = readl(port->membase + AUART_CTRL0);
writel(AUART_CTRL0_CLKGATE,
port->membase + AUART_CTRL0_CLR);
writel(AUART_CTRL2_UARTEN | AUART_CTRL2_TXE,
port->membase + AUART_CTRL2_SET);
uart_console_write(port, str, count, mxs_auart_console_putchar);
/* Finally, wait for transmitter to become empty ... */
while (readl(port->membase + AUART_STAT) & AUART_STAT_BUSY) {
udelay(1);
if (!to--)
break;
}
/*
* ... and restore the TCR if we waited long enough for the transmitter
* to be idle. This might keep the transmitter enabled although it is
* unused, but that is better than to disable it while it is still
* transmitting.
*/
if (!(readl(port->membase + AUART_STAT) & AUART_STAT_BUSY)) {
writel(old_ctrl0, port->membase + AUART_CTRL0);
writel(old_ctrl2, port->membase + AUART_CTRL2);
}
clk_disable(s->clk);
}
static void __init
auart_console_get_options(struct uart_port *port, int *baud,
int *parity, int *bits)
{
unsigned int lcr_h, quot;
if (!(readl(port->membase + AUART_CTRL2) & AUART_CTRL2_UARTEN))
return;
lcr_h = readl(port->membase + AUART_LINECTRL);
*parity = 'n';
if (lcr_h & AUART_LINECTRL_PEN) {
if (lcr_h & AUART_LINECTRL_EPS)
*parity = 'e';
else
*parity = 'o';
}
if ((lcr_h & AUART_LINECTRL_WLEN_MASK) == AUART_LINECTRL_WLEN(2))
*bits = 7;
else
*bits = 8;
quot = ((readl(port->membase + AUART_LINECTRL)
& AUART_LINECTRL_BAUD_DIVINT_MASK))
>> (AUART_LINECTRL_BAUD_DIVINT_SHIFT - 6);
quot |= ((readl(port->membase + AUART_LINECTRL)
& AUART_LINECTRL_BAUD_DIVFRAC_MASK))
>> AUART_LINECTRL_BAUD_DIVFRAC_SHIFT;
if (quot == 0)
quot = 1;
*baud = (port->uartclk << 2) / quot;
}
static int __init
auart_console_setup(struct console *co, char *options)
{
struct mxs_auart_port *s;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
if (co->index == -1 || co->index >= ARRAY_SIZE(auart_port))
co->index = 0;
s = auart_port[co->index];
if (!s)
return -ENODEV;
clk_prepare_enable(s->clk);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
auart_console_get_options(&s->port, &baud, &parity, &bits);
ret = uart_set_options(&s->port, co, baud, parity, bits, flow);
clk_disable_unprepare(s->clk);
return ret;
}
static struct console auart_console = {
.name = "ttyAPP",
.write = auart_console_write,
.device = uart_console_device,
.setup = auart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &auart_driver,
};
#endif
static struct uart_driver auart_driver = {
.owner = THIS_MODULE,
.driver_name = "ttyAPP",
.dev_name = "ttyAPP",
.major = 0,
.minor = 0,
.nr = MXS_AUART_PORTS,
#ifdef CONFIG_SERIAL_MXS_AUART_CONSOLE
.cons = &auart_console,
#endif
};
/*
* This function returns 1 if pdev isn't a device instatiated by dt, 0 if it
* could successfully get all information from dt or a negative errno.
*/
static int serial_mxs_probe_dt(struct mxs_auart_port *s,
struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
int ret;
if (!np)
/* no device tree device */
return 1;
ret = of_alias_get_id(np, "serial");
if (ret < 0) {
dev_err(&pdev->dev, "failed to get alias id: %d\n", ret);
return ret;
}
s->port.line = ret;
if (of_get_property(np, "fsl,uart-has-rtscts", NULL))
set_bit(MXS_AUART_RTSCTS, &s->flags);
return 0;
}
static int mxs_auart_probe(struct platform_device *pdev)
{
const struct of_device_id *of_id =
of_match_device(mxs_auart_dt_ids, &pdev->dev);
struct mxs_auart_port *s;
u32 version;
int ret = 0;
struct resource *r;
s = kzalloc(sizeof(struct mxs_auart_port), GFP_KERNEL);
if (!s) {
ret = -ENOMEM;
goto out;
}
ret = serial_mxs_probe_dt(s, pdev);
if (ret > 0)
s->port.line = pdev->id < 0 ? 0 : pdev->id;
else if (ret < 0)
goto out_free;
if (of_id) {
pdev->id_entry = of_id->data;
s->devtype = pdev->id_entry->driver_data;
}
s->clk = clk_get(&pdev->dev, NULL);
if (IS_ERR(s->clk)) {
ret = PTR_ERR(s->clk);
goto out_free;
}
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!r) {
ret = -ENXIO;
goto out_free_clk;
}
s->port.mapbase = r->start;
s->port.membase = ioremap(r->start, resource_size(r));
s->port.ops = &mxs_auart_ops;
s->port.iotype = UPIO_MEM;
s->port.fifosize = MXS_AUART_FIFO_SIZE;
s->port.uartclk = clk_get_rate(s->clk);
s->port.type = PORT_IMX;
s->port.dev = s->dev = &pdev->dev;
s->ctrl = 0;
s->irq = platform_get_irq(pdev, 0);
s->port.irq = s->irq;
ret = request_irq(s->irq, mxs_auart_irq_handle, 0, dev_name(&pdev->dev), s);
if (ret)
goto out_free_clk;
platform_set_drvdata(pdev, s);
auart_port[s->port.line] = s;
mxs_auart_reset(&s->port);
ret = uart_add_one_port(&auart_driver, &s->port);
if (ret)
goto out_free_irq;
version = readl(s->port.membase + AUART_VERSION);
dev_info(&pdev->dev, "Found APPUART %d.%d.%d\n",
(version >> 24) & 0xff,
(version >> 16) & 0xff, version & 0xffff);
return 0;
out_free_irq:
auart_port[pdev->id] = NULL;
free_irq(s->irq, s);
out_free_clk:
clk_put(s->clk);
out_free:
kfree(s);
out:
return ret;
}
static int mxs_auart_remove(struct platform_device *pdev)
{
struct mxs_auart_port *s = platform_get_drvdata(pdev);
uart_remove_one_port(&auart_driver, &s->port);
auart_port[pdev->id] = NULL;
clk_put(s->clk);
free_irq(s->irq, s);
kfree(s);
return 0;
}
static struct platform_driver mxs_auart_driver = {
.probe = mxs_auart_probe,
.remove = mxs_auart_remove,
.driver = {
.name = "mxs-auart",
.owner = THIS_MODULE,
.of_match_table = mxs_auart_dt_ids,
},
};
static int __init mxs_auart_init(void)
{
int r;
r = uart_register_driver(&auart_driver);
if (r)
goto out;
r = platform_driver_register(&mxs_auart_driver);
if (r)
goto out_err;
return 0;
out_err:
uart_unregister_driver(&auart_driver);
out:
return r;
}
static void __exit mxs_auart_exit(void)
{
platform_driver_unregister(&mxs_auart_driver);
uart_unregister_driver(&auart_driver);
}
module_init(mxs_auart_init);
module_exit(mxs_auart_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Freescale MXS application uart driver");
MODULE_ALIAS("platform:mxs-auart");