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author | Claudio Scordino <claudio@evidence.eu.com> | 2010-05-03 13:31:28 +0100 |
---|---|---|
committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-05-04 16:59:11 +0100 |
commit | e8faff7330a3501eafc9bfe5f4f15af444be29f5 (patch) | |
tree | f0348e3831698baed6cc122972b8239bd155ecdf /drivers/serial/atmel_serial.c | |
parent | aec9562f3db8ece218125042e0b2b7ac5b7091e7 (diff) | |
download | linux-e8faff7330a3501eafc9bfe5f4f15af444be29f5.tar.gz linux-e8faff7330a3501eafc9bfe5f4f15af444be29f5.tar.bz2 linux-e8faff7330a3501eafc9bfe5f4f15af444be29f5.zip |
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>
Diffstat (limited to 'drivers/serial/atmel_serial.c')
-rw-r--r-- | drivers/serial/atmel_serial.c | 207 |
1 files changed, 173 insertions, 34 deletions
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index 2c9bf9b68327..eed3c2d8dd1c 100644 --- a/drivers/serial/atmel_serial.c +++ b/drivers/serial/atmel_serial.c @@ -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; |