diff options
| -rw-r--r-- | drivers/serial/atmel_serial.c | 245 |
1 files changed, 190 insertions, 55 deletions
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index e06c6c8f4dd..f0f6ea3a9ee 100644 --- a/drivers/serial/atmel_serial.c +++ b/drivers/serial/atmel_serial.c @@ -103,6 +103,13 @@ static int (*atmel_open_hook)(struct uart_port *); static void (*atmel_close_hook)(struct uart_port *); +struct atmel_uart_char { + u16 status; + u16 ch; +}; + +#define ATMEL_SERIAL_RINGSIZE 1024 + /* * We wrap our port structure around the generic uart_port. */ @@ -111,6 +118,12 @@ struct atmel_uart_port { struct clk *clk; /* uart clock */ unsigned short suspended; /* is port suspended? */ int break_active; /* break being received */ + + struct tasklet_struct tasklet; + unsigned int irq_status; + unsigned int irq_status_prev; + + struct circ_buf rx_ring; }; static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART]; @@ -240,22 +253,42 @@ static void atmel_break_ctl(struct uart_port *port, int break_state) } /* + * Stores the incoming character in the ring buffer + */ +static void +atmel_buffer_rx_char(struct uart_port *port, unsigned int status, + unsigned int ch) +{ + struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; + struct circ_buf *ring = &atmel_port->rx_ring; + struct atmel_uart_char *c; + + if (!CIRC_SPACE(ring->head, ring->tail, ATMEL_SERIAL_RINGSIZE)) + /* Buffer overflow, ignore char */ + return; + + c = &((struct atmel_uart_char *)ring->buf)[ring->head]; + c->status = status; + c->ch = ch; + + /* Make sure the character is stored before we update head. */ + smp_wmb(); + + ring->head = (ring->head + 1) & (ATMEL_SERIAL_RINGSIZE - 1); +} + +/* * Characters received (called from interrupt handler) */ static void atmel_rx_chars(struct uart_port *port) { struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; - struct tty_struct *tty = port->info->tty; - unsigned int status, ch, flg; + unsigned int status, ch; status = UART_GET_CSR(port); while (status & ATMEL_US_RXRDY) { ch = UART_GET_CHAR(port); - port->icount.rx++; - - flg = TTY_NORMAL; - /* * note that the error handling code is * out of the main execution path @@ -263,17 +296,14 @@ static void atmel_rx_chars(struct uart_port *port) if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME | ATMEL_US_OVRE | ATMEL_US_RXBRK) || atmel_port->break_active)) { + /* clear error */ UART_PUT_CR(port, ATMEL_US_RSTSTA); + if (status & ATMEL_US_RXBRK && !atmel_port->break_active) { - /* ignore side-effect */ - status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); - port->icount.brk++; atmel_port->break_active = 1; UART_PUT_IER(port, ATMEL_US_RXBRK); - if (uart_handle_break(port)) - goto ignore_char; } else { /* * This is either the end-of-break @@ -286,52 +316,30 @@ static void atmel_rx_chars(struct uart_port *port) status &= ~ATMEL_US_RXBRK; atmel_port->break_active = 0; } - if (status & ATMEL_US_PARE) - port->icount.parity++; - if (status & ATMEL_US_FRAME) - port->icount.frame++; - if (status & ATMEL_US_OVRE) - port->icount.overrun++; - - status &= port->read_status_mask; - - if (status & ATMEL_US_RXBRK) - flg = TTY_BREAK; - else if (status & ATMEL_US_PARE) - flg = TTY_PARITY; - else if (status & ATMEL_US_FRAME) - flg = TTY_FRAME; } - if (uart_handle_sysrq_char(port, ch)) - goto ignore_char; - - uart_insert_char(port, status, ATMEL_US_OVRE, ch, flg); - -ignore_char: + atmel_buffer_rx_char(port, status, ch); status = UART_GET_CSR(port); } - tty_flip_buffer_push(tty); + tasklet_schedule(&atmel_port->tasklet); } /* - * Transmit characters (called from interrupt handler) + * Transmit characters (called from tasklet with TXRDY interrupt + * disabled) */ static void atmel_tx_chars(struct uart_port *port) { struct circ_buf *xmit = &port->info->xmit; - if (port->x_char) { + if (port->x_char && UART_GET_CSR(port) & ATMEL_US_TXRDY) { UART_PUT_CHAR(port, port->x_char); port->icount.tx++; port->x_char = 0; - return; } - if (uart_circ_empty(xmit) || uart_tx_stopped(port)) { - atmel_stop_tx(port); + if (uart_circ_empty(xmit) || uart_tx_stopped(port)) return; - } while (UART_GET_CSR(port) & ATMEL_US_TXRDY) { UART_PUT_CHAR(port, xmit->buf[xmit->tail]); @@ -344,8 +352,8 @@ static void atmel_tx_chars(struct uart_port *port) if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); - if (uart_circ_empty(xmit)) - atmel_stop_tx(port); + if (!uart_circ_empty(xmit)) + UART_PUT_IER(port, ATMEL_US_TXRDY); } /* @@ -371,14 +379,18 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending) } /* - * transmit interrupt handler. + * transmit interrupt handler. (Transmit is IRQF_NODELAY safe) */ static void atmel_handle_transmit(struct uart_port *port, unsigned int pending) { + struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; + /* Interrupt transmit */ - if (pending & ATMEL_US_TXRDY) - atmel_tx_chars(port); + if (pending & ATMEL_US_TXRDY) { + UART_PUT_IDR(port, ATMEL_US_TXRDY); + tasklet_schedule(&atmel_port->tasklet); + } } /* @@ -388,18 +400,13 @@ static void atmel_handle_status(struct uart_port *port, unsigned int pending, unsigned int status) { - /* TODO: All reads to CSR will clear these interrupts! */ - if (pending & ATMEL_US_RIIC) - port->icount.rng++; - if (pending & ATMEL_US_DSRIC) - port->icount.dsr++; - if (pending & ATMEL_US_DCDIC) - uart_handle_dcd_change(port, !(status & ATMEL_US_DCD)); - if (pending & ATMEL_US_CTSIC) - uart_handle_cts_change(port, !(status & ATMEL_US_CTS)); + struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; + if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC - | ATMEL_US_CTSIC)) - wake_up_interruptible(&port->info->delta_msr_wait); + | ATMEL_US_CTSIC)) { + atmel_port->irq_status = status; + tasklet_schedule(&atmel_port->tasklet); + } } /* @@ -426,6 +433,114 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } +static void atmel_rx_from_ring(struct uart_port *port) +{ + struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; + struct circ_buf *ring = &atmel_port->rx_ring; + unsigned int flg; + unsigned int status; + + while (ring->head != ring->tail) { + struct atmel_uart_char c; + + /* Make sure c is loaded after head. */ + smp_rmb(); + + c = ((struct atmel_uart_char *)ring->buf)[ring->tail]; + + ring->tail = (ring->tail + 1) & (ATMEL_SERIAL_RINGSIZE - 1); + + port->icount.rx++; + status = c.status; + flg = TTY_NORMAL; + + /* + * note that the error handling code is + * out of the main execution path + */ + if (unlikely(status & (ATMEL_US_PARE | ATMEL_US_FRAME + | ATMEL_US_OVRE | ATMEL_US_RXBRK))) { + if (status & ATMEL_US_RXBRK) { + /* ignore side-effect */ + status &= ~(ATMEL_US_PARE | ATMEL_US_FRAME); + + port->icount.brk++; + if (uart_handle_break(port)) + continue; + } + if (status & ATMEL_US_PARE) + port->icount.parity++; + if (status & ATMEL_US_FRAME) + port->icount.frame++; + if (status & ATMEL_US_OVRE) + port->icount.overrun++; + + status &= port->read_status_mask; + + if (status & ATMEL_US_RXBRK) + flg = TTY_BREAK; + else if (status & ATMEL_US_PARE) + flg = TTY_PARITY; + else if (status & ATMEL_US_FRAME) + flg = TTY_FRAME; + } + + + if (uart_handle_sysrq_char(port, c.ch)) + continue; + + uart_insert_char(port, status, ATMEL_US_OVRE, c.ch, flg); + } + + /* + * Drop the lock here since it might end up calling + * uart_start(), which takes the lock. + */ + spin_unlock(&port->lock); + tty_flip_buffer_push(port->info->tty); + spin_lock(&port->lock); +} + +/* + * tasklet handling tty stuff outside the interrupt handler. + */ +static void atmel_tasklet_func(unsigned long data) +{ + struct uart_port *port = (struct uart_port *)data; + struct atmel_uart_port *atmel_port = (struct atmel_uart_port *)port; + unsigned int status; + unsigned int status_change; + + /* The interrupt handler does not take the lock */ + spin_lock(&port->lock); + + atmel_tx_chars(port); + + status = atmel_port->irq_status; + status_change = status ^ atmel_port->irq_status_prev; + + if (status_change & (ATMEL_US_RI | ATMEL_US_DSR + | ATMEL_US_DCD | ATMEL_US_CTS)) { + /* TODO: All reads to CSR will clear these interrupts! */ + if (status_change & ATMEL_US_RI) + port->icount.rng++; + if (status_change & ATMEL_US_DSR) + port->icount.dsr++; + if (status_change & ATMEL_US_DCD) + uart_handle_dcd_change(port, !(status & ATMEL_US_DCD)); + if (status_change & ATMEL_US_CTS) + uart_handle_cts_change(port, !(status & ATMEL_US_CTS)); + + wake_up_interruptible(&port->info->delta_msr_wait); + + atmel_port->irq_status_prev = status; + } + + atmel_rx_from_ring(port); + + spin_unlock(&port->lock); +} + /* * Perform initialization and enable port for reception */ @@ -757,6 +872,11 @@ static void __devinit atmel_init_port(struct atmel_uart_port *atmel_port, port->mapbase = pdev->resource[0].start; port->irq = pdev->resource[1].start; + tasklet_init(&atmel_port->tasklet, atmel_tasklet_func, + (unsigned long)port); + + memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring)); + if (data->regs) /* Already mapped by setup code */ port->membase = data->regs; @@ -997,11 +1117,20 @@ static int atmel_serial_resume(struct platform_device *pdev) static int __devinit atmel_serial_probe(struct platform_device *pdev) { struct atmel_uart_port *port; + void *data; int ret; + BUILD_BUG_ON(!is_power_of_2(ATMEL_SERIAL_RINGSIZE)); + port = &atmel_ports[pdev->id]; atmel_init_port(port, pdev); + ret = -ENOMEM; + data = kmalloc(ATMEL_SERIAL_RINGSIZE, GFP_KERNEL); + if (!data) + goto err_alloc_ring; + port->rx_ring.buf = data; + ret = uart_add_one_port(&atmel_uart, &port->uart); if (ret) goto err_add_port; @@ -1012,6 +1141,9 @@ static int __devinit atmel_serial_probe(struct platform_device *pdev) return 0; err_add_port: + kfree(port->rx_ring.buf); + port->rx_ring.buf = NULL; +err_alloc_ring: if (!atmel_is_console_port(&port->uart)) { clk_disable(port->clk); clk_put(port->clk); @@ -1032,6 +1164,9 @@ static int __devexit atmel_serial_remove(struct platform_device *pdev) ret = uart_remove_one_port(&atmel_uart, port); + tasklet_kill(&atmel_port->tasklet); + kfree(atmel_port->rx_ring.buf); + /* "port" is allocated statically, so we shouldn't free it */ clk_disable(atmel_port->clk); |