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ARM: 6092/1: atmel_serial: support for RS485 communications 

Final version of the patch that adds support for RS485 communications to the atmel_serial driver.

The patch has been already sent and discussed on both linux-kernel and linux-arm-kernel mailing lists several times.

Many people collaborated to improve and test the code:

Tested-by: Sebastian Heutling <Sebastian.Heutling@who-ing.de>
Tested-by: Bernhard Roth <br@pwrnet.de>
Reviewed-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com>
Signed-off-by: Michael Trimarchi <michael@evidence.eu.com>
Signed-off-by: Rick Bronson <rick@efn.org>
Signed-off-by: Sebastian Heutling <Sebastian.Heutling@who-ing.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Claudio Scordino 2010-05-03 13:31:28 +01:00 committed by Russell King
parent aec9562f3d
commit e8faff7330
3 changed files with 181 additions and 37 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm/include/asm/ioctls.h
View File

@ -53,6 +53,9 @@
#define TIOCGPTN _IOR('T',0x30, unsigned int) /* Get Pty Number (of pty-mux device) */
#define TIOCSPTLCK _IOW('T',0x31, int) /* Lock/unlock Pty */
#define TIOCGRS485 0x542E
#define TIOCSRS485 0x542F
#define FIONCLEX 0x5450 /* these numbers need to be adjusted. */
#define FIOCLEX 0x5451
#define FIOASYNC 0x5452

8
arch/arm/mach-at91/include/mach/board.h
View File

@ -39,6 +39,7 @@
#include <linux/usb/atmel_usba_udc.h>
#include <linux/atmel-mci.h>
#include <sound/atmel-ac97c.h>
#include <linux/serial.h>
/* USB Device */
struct at91_udc_data {
@ -143,9 +144,10 @@ extern struct platform_device *atmel_default_console_device;
extern void __init __deprecated at91_init_serial(struct at91_uart_config *config);
struct atmel_uart_data {
short use_dma_tx; /* use transmit DMA? */
short use_dma_rx; /* use receive DMA? */
void __iomem *regs; /* virtual base address, if any */
short use_dma_tx; /* use transmit DMA? */
short use_dma_rx; /* use receive DMA? */
void __iomem *regs; /* virt. base address, if any */
struct serial_rs485 rs485; /* rs485 settings */
};
extern void __init at91_add_device_serial(void);

207
drivers/serial/atmel_serial.c
View File

@ -38,6 +38,7 @@
#include <linux/dma-mapping.h>
#include <linux/atmel_pdc.h>
#include <linux/atmel_serial.h>
#include <linux/uaccess.h>
#include <asm/io.h>
@ -59,6 +60,9 @@
#include <linux/serial_core.h>
static void atmel_start_rx(struct uart_port *port);
static void atmel_stop_rx(struct uart_port *port);
#ifdef CONFIG_SERIAL_ATMEL_TTYAT
/* Use device name ttyAT, major 204 and minor 154-169. This is necessary if we
@ -93,6 +97,7 @@
#define UART_GET_BRGR(port) __raw_readl((port)->membase + ATMEL_US_BRGR)
#define UART_PUT_BRGR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_BRGR)
#define UART_PUT_RTOR(port,v) __raw_writel(v, (port)->membase + ATMEL_US_RTOR)
#define UART_PUT_TTGR(port, v) __raw_writel(v, (port)->membase + ATMEL_US_TTGR)
/* PDC registers */
#define UART_PUT_PTCR(port,v) __raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)
@ -147,6 +152,9 @@ struct atmel_uart_port {
unsigned int irq_status_prev;
struct circ_buf rx_ring;
struct serial_rs485 rs485; /* rs485 settings */
unsigned int tx_done_mask;
};
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
@ -187,6 +195,46 @@ static bool atmel_use_dma_tx(struct uart_port *port)
}
#endif
/* Enable or disable the rs485 support */
void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int mode;
spin_lock(&port->lock);
/* Disable interrupts */
UART_PUT_IDR(port, atmel_port->tx_done_mask);
mode = UART_GET_MR(port);
/* Resetting serial mode to RS232 (0x0) */
mode &= ~ATMEL_US_USMODE;
atmel_port->rs485 = *rs485conf;
if (rs485conf->flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
UART_PUT_TTGR(port, rs485conf->delay_rts_before_send);
mode |= ATMEL_US_USMODE_RS485;
} else {
dev_dbg(port->dev, "Setting UART to RS232\n");
if (atmel_use_dma_tx(port))
atmel_port->tx_done_mask = ATMEL_US_ENDTX |
ATMEL_US_TXBUFE;
else
atmel_port->tx_done_mask = ATMEL_US_TXRDY;
}
UART_PUT_MR(port, mode);
/* Enable interrupts */
UART_PUT_IER(port, atmel_port->tx_done_mask);
spin_unlock(&port->lock);
}
/*
* Return TIOCSER_TEMT when transmitter FIFO and Shift register is empty.
*/
@ -202,6 +250,7 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
{
unsigned int control = 0;
unsigned int mode;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
#ifdef CONFIG_ARCH_AT91RM9200
if (cpu_is_at91rm9200()) {
@ -236,6 +285,17 @@ static void atmel_set_mctrl(struct uart_port *port, u_int mctrl)
mode |= ATMEL_US_CHMODE_LOC_LOOP;
else
mode |= ATMEL_US_CHMODE_NORMAL;
/* Resetting serial mode to RS232 (0x0) */
mode &= ~ATMEL_US_USMODE;
if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send);
mode |= ATMEL_US_USMODE_RS485;
} else {
dev_dbg(port->dev, "Setting UART to RS232\n");
}
UART_PUT_MR(port, mode);
}
@ -268,12 +328,17 @@ static u_int atmel_get_mctrl(struct uart_port *port)
*/
static void atmel_stop_tx(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_tx(port)) {
/* disable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
} else
UART_PUT_IDR(port, ATMEL_US_TXRDY);
}
/* Disable interrupts */
UART_PUT_IDR(port, atmel_port->tx_done_mask);
if (atmel_port->rs485.flags & SER_RS485_ENABLED)
atmel_start_rx(port);
}
/*
@ -281,17 +346,39 @@ static void atmel_stop_tx(struct uart_port *port)
*/
static void atmel_start_tx(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_tx(port)) {
if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)
/* The transmitter is already running. Yes, we
really need this.*/
return;
UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
if (atmel_port->rs485.flags & SER_RS485_ENABLED)
atmel_stop_rx(port);
/* re-enable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
} else
UART_PUT_IER(port, ATMEL_US_TXRDY);
}
/* Enable interrupts */
UART_PUT_IER(port, atmel_port->tx_done_mask);
}
/*
* start receiving - port is in process of being opened.
*/
static void atmel_start_rx(struct uart_port *port)
{
UART_PUT_CR(port, ATMEL_US_RSTSTA); /* reset status and receiver */
if (atmel_use_dma_rx(port)) {
/* enable PDC controller */
UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
port->read_status_mask);
UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
} else {
UART_PUT_IER(port, ATMEL_US_RXRDY);
}
}
/*
@ -302,9 +389,11 @@ static void atmel_stop_rx(struct uart_port *port)
if (atmel_use_dma_rx(port)) {
/* disable PDC receive */
UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS);
UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
} else
UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
port->read_status_mask);
} else {
UART_PUT_IDR(port, ATMEL_US_RXRDY);
}
}
/*
@ -428,8 +517,9 @@ static void atmel_rx_chars(struct uart_port *port)
static void atmel_tx_chars(struct uart_port *port)
{
struct circ_buf *xmit = &port->state->xmit;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) {
if (port->x_char && UART_GET_CSR(port) & atmel_port->tx_done_mask) {
UART_PUT_CHAR(port, port->x_char);
port->icount.tx++;
port->x_char = 0;
@ -437,7 +527,7 @@ static void atmel_tx_chars(struct uart_port *port)
if (uart_circ_empty(xmit) || uart_tx_stopped(port))
return;
while (UART_GET_CSR(port) & ATMEL_US_TXRDY) {
while (UART_GET_CSR(port) & atmel_port->tx_done_mask) {
UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
@ -449,7 +539,8 @@ static void atmel_tx_chars(struct uart_port *port)
uart_write_wakeup(port);
if (!uart_circ_empty(xmit))
UART_PUT_IER(port, ATMEL_US_TXRDY);
/* Enable interrupts */
UART_PUT_IER(port, atmel_port->tx_done_mask);
}
/*
@ -501,18 +592,10 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
if (atmel_use_dma_tx(port)) {
/* PDC transmit */
if (pending & (ATMEL_US_ENDTX | ATMEL_US_TXBUFE)) {
UART_PUT_IDR(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
tasklet_schedule(&atmel_port->tasklet);
}
} else {
/* Interrupt transmit */
if (pending & ATMEL_US_TXRDY) {
UART_PUT_IDR(port, ATMEL_US_TXRDY);
tasklet_schedule(&atmel_port->tasklet);
}
if (pending & atmel_port->tx_done_mask) {
/* Either PDC or interrupt transmission */
UART_PUT_IDR(port, atmel_port->tx_done_mask);
tasklet_schedule(&atmel_port->tasklet);
}
}
@ -590,9 +673,15 @@ static void atmel_tx_dma(struct uart_port *port)
UART_PUT_TPR(port, pdc->dma_addr + xmit->tail);
UART_PUT_TCR(port, count);
/* re-enable PDC transmit and interrupts */
/* re-enable PDC transmit */
UART_PUT_PTCR(port, ATMEL_PDC_TXTEN);
UART_PUT_IER(port, ATMEL_US_ENDTX | ATMEL_US_TXBUFE);
/* Enable interrupts */
UART_PUT_IER(port, atmel_port->tx_done_mask);
} else {
if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
/* DMA done, stop TX, start RX for RS485 */
atmel_start_rx(port);
}
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
@ -1017,6 +1106,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
{
unsigned long flags;
unsigned int mode, imr, quot, baud;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
/* Get current mode register */
mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL
@ -1115,6 +1205,17 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
/* disable receiver and transmitter */
UART_PUT_CR(port, ATMEL_US_TXDIS | ATMEL_US_RXDIS);
/* Resetting serial mode to RS232 (0x0) */
mode &= ~ATMEL_US_USMODE;
if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
dev_dbg(port->dev, "Setting UART to RS485\n");
UART_PUT_TTGR(port, atmel_port->rs485.delay_rts_before_send);
mode |= ATMEL_US_USMODE_RS485;
} else {
dev_dbg(port->dev, "Setting UART to RS232\n");
}
/* set the parity, stop bits and data size */
UART_PUT_MR(port, mode);
@ -1231,6 +1332,35 @@ static void atmel_poll_put_char(struct uart_port *port, unsigned char ch)
}
#endif
static int
atmel_ioctl(struct uart_port *port, unsigned int cmd, unsigned long arg)
{
struct serial_rs485 rs485conf;
switch (cmd) {
case TIOCSRS485:
if (copy_from_user(&rs485conf, (struct serial_rs485 *) arg,
sizeof(rs485conf)))
return -EFAULT;
atmel_config_rs485(port, &rs485conf);
break;
case TIOCGRS485:
if (copy_to_user((struct serial_rs485 *) arg,
&(to_atmel_uart_port(port)->rs485),
sizeof(rs485conf)))
return -EFAULT;
break;
default:
return -ENOIOCTLCMD;
}
return 0;
}
static struct uart_ops atmel_pops = {
.tx_empty = atmel_tx_empty,
.set_mctrl = atmel_set_mctrl,
@ -1250,6 +1380,7 @@ static struct uart_ops atmel_pops = {
.config_port = atmel_config_port,
.verify_port = atmel_verify_port,
.pm = atmel_serial_pm,
.ioctl = atmel_ioctl,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = atmel_poll_get_char,
.poll_put_char = atmel_poll_put_char,
@ -1265,13 +1396,12 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
struct uart_port *port = &atmel_port->uart;
struct atmel_uart_data *data = pdev->dev.platform_data;
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &atmel_pops;
port->fifosize = 1;
port->line = pdev->id;
port->dev = &pdev->dev;
port->iotype = UPIO_MEM;
port->flags = UPF_BOOT_AUTOCONF;
port->ops = &atmel_pops;
port->fifosize = 1;
port->line = pdev->id;
port->dev = &pdev->dev;
port->mapbase = pdev->resource[0].start;
port->irq = pdev->resource[1].start;
@ -1299,8 +1429,16 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port,
atmel_port->use_dma_rx = data->use_dma_rx;
atmel_port->use_dma_tx = data->use_dma_tx;
if (atmel_use_dma_tx(port))
atmel_port->rs485 = data->rs485;
/* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
if (atmel_port->rs485.flags & SER_RS485_ENABLED)
atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
else if (atmel_use_dma_tx(port)) {
port->fifosize = PDC_BUFFER_SIZE;
atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
} else {
atmel_port->tx_done_mask = ATMEL_US_TXRDY;
}
}
/*
@ -1334,6 +1472,7 @@ static void atmel_console_putchar(struct uart_port *port, int ch)
static void atmel_console_write(struct console *co, const char *s, u_int count)
{
struct uart_port *port = &atmel_ports[co->index].uart;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
unsigned int status, imr;
unsigned int pdc_tx;
@ -1341,7 +1480,7 @@ static void atmel_console_write(struct console *co, const char *s, u_int count)
* First, save IMR and then disable interrupts
*/
imr = UART_GET_IMR(port);
UART_PUT_IDR(port, ATMEL_US_RXRDY | ATMEL_US_TXRDY);
UART_PUT_IDR(port, ATMEL_US_RXRDY | atmel_port->tx_done_mask);
/* Store PDC transmit status and disable it */
pdc_tx = UART_GET_PTSR(port) & ATMEL_PDC_TXTEN;