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path: root/drivers/tty/serial/atmel_serial.c
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Diffstat (limited to 'drivers/tty/serial/atmel_serial.c')
-rw-r--r--drivers/tty/serial/atmel_serial.c143
1 files changed, 86 insertions, 57 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 954941dd8124..2eaa18ddef61 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -108,6 +108,12 @@ struct atmel_uart_char {
u16 ch;
};
+/*
+ * Be careful, the real size of the ring buffer is
+ * sizeof(atmel_uart_char) * ATMEL_SERIAL_RINGSIZE. It means that ring buffer
+ * can contain up to 1024 characters in PIO mode and up to 4096 characters in
+ * DMA mode.
+ */
#define ATMEL_SERIAL_RINGSIZE 1024
/*
@@ -145,10 +151,10 @@ struct atmel_uart_port {
dma_cookie_t cookie_rx;
struct scatterlist sg_tx;
struct scatterlist sg_rx;
- struct tasklet_struct tasklet;
- unsigned int irq_status;
+ struct tasklet_struct tasklet_rx;
+ struct tasklet_struct tasklet_tx;
+ atomic_t tasklet_shutdown;
unsigned int irq_status_prev;
- unsigned int status_change;
unsigned int tx_len;
struct circ_buf rx_ring;
@@ -281,6 +287,13 @@ static bool atmel_use_fifo(struct uart_port *port)
return atmel_port->fifo_size;
}
+static void atmel_tasklet_schedule(struct atmel_uart_port *atmel_port,
+ struct tasklet_struct *t)
+{
+ if (!atomic_read(&atmel_port->tasklet_shutdown))
+ tasklet_schedule(t);
+}
+
static unsigned int atmel_get_lines_status(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
@@ -482,19 +495,21 @@ static void atmel_start_tx(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- if (atmel_use_pdc_tx(port)) {
- if (atmel_uart_readl(port, ATMEL_PDC_PTSR) & ATMEL_PDC_TXTEN)
- /* The transmitter is already running. Yes, we
- really need this.*/
- return;
+ if (atmel_use_pdc_tx(port) && (atmel_uart_readl(port, ATMEL_PDC_PTSR)
+ & ATMEL_PDC_TXTEN))
+ /* The transmitter is already running. Yes, we
+ really need this.*/
+ return;
+ if (atmel_use_pdc_tx(port) || atmel_use_dma_tx(port))
if ((port->rs485.flags & SER_RS485_ENABLED) &&
!(port->rs485.flags & SER_RS485_RX_DURING_TX))
atmel_stop_rx(port);
+ if (atmel_use_pdc_tx(port))
/* re-enable PDC transmit */
atmel_uart_writel(port, ATMEL_PDC_PTCR, ATMEL_PDC_TXTEN);
- }
+
/* Enable interrupts */
atmel_uart_writel(port, ATMEL_US_IER, atmel_port->tx_done_mask);
}
@@ -710,7 +725,7 @@ static void atmel_rx_chars(struct uart_port *port)
status = atmel_uart_readl(port, ATMEL_US_CSR);
}
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
}
/*
@@ -781,7 +796,7 @@ static void atmel_complete_tx_dma(void *arg)
* remaining data from the beginning of xmit->buf to xmit->head.
*/
if (!uart_circ_empty(xmit))
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -966,7 +981,7 @@ static void atmel_complete_rx_dma(void *arg)
struct uart_port *port = arg;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
}
static void atmel_release_rx_dma(struct uart_port *port)
@@ -1006,7 +1021,7 @@ static void atmel_rx_from_dma(struct uart_port *port)
if (dmastat == DMA_ERROR) {
dev_dbg(port->dev, "Get residue error, restart tasklet\n");
atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_rx);
return;
}
@@ -1160,8 +1175,11 @@ static void atmel_uart_timer_callback(unsigned long data)
struct uart_port *port = (void *)data;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- tasklet_schedule(&atmel_port->tasklet);
- mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port));
+ if (!atomic_read(&atmel_port->tasklet_shutdown)) {
+ tasklet_schedule(&atmel_port->tasklet_rx);
+ mod_timer(&atmel_port->uart_timer,
+ jiffies + uart_poll_timeout(port));
+ }
}
/*
@@ -1183,7 +1201,8 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
atmel_uart_writel(port, ATMEL_US_IDR,
(ATMEL_US_ENDRX | ATMEL_US_TIMEOUT));
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port,
+ &atmel_port->tasklet_rx);
}
if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
@@ -1195,7 +1214,8 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
if (pending & ATMEL_US_TIMEOUT) {
atmel_uart_writel(port, ATMEL_US_IDR,
ATMEL_US_TIMEOUT);
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port,
+ &atmel_port->tasklet_rx);
}
}
@@ -1225,7 +1245,7 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
/* Either PDC or interrupt transmission */
atmel_uart_writel(port, ATMEL_US_IDR,
atmel_port->tx_done_mask);
- tasklet_schedule(&atmel_port->tasklet);
+ atmel_tasklet_schedule(atmel_port, &atmel_port->tasklet_tx);
}
}
@@ -1237,14 +1257,27 @@ atmel_handle_status(struct uart_port *port, unsigned int pending,
unsigned int status)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ unsigned int status_change;
if (pending & (ATMEL_US_RIIC | ATMEL_US_DSRIC | ATMEL_US_DCDIC
| ATMEL_US_CTSIC)) {
- atmel_port->irq_status = status;
- atmel_port->status_change = atmel_port->irq_status ^
- atmel_port->irq_status_prev;
+ status_change = status ^ atmel_port->irq_status_prev;
atmel_port->irq_status_prev = status;
- tasklet_schedule(&atmel_port->tasklet);
+
+ 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->state->port.delta_msr_wait);
+ }
}
}
@@ -1571,37 +1604,25 @@ static int atmel_prepare_rx_pdc(struct uart_port *port)
/*
* tasklet handling tty stuff outside the interrupt handler.
*/
-static void atmel_tasklet_func(unsigned long data)
+static void atmel_tasklet_rx_func(unsigned long data)
{
struct uart_port *port = (struct uart_port *)data;
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
- unsigned int status = atmel_port->irq_status;
- unsigned int status_change = atmel_port->status_change;
/* The interrupt handler does not take the lock */
spin_lock(&port->lock);
-
- atmel_port->schedule_tx(port);
-
- 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->state->port.delta_msr_wait);
-
- atmel_port->status_change = 0;
- }
-
atmel_port->schedule_rx(port);
+ spin_unlock(&port->lock);
+}
+
+static void atmel_tasklet_tx_func(unsigned long data)
+{
+ struct uart_port *port = (struct uart_port *)data;
+ struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ /* The interrupt handler does not take the lock */
+ spin_lock(&port->lock);
+ atmel_port->schedule_tx(port);
spin_unlock(&port->lock);
}
@@ -1785,7 +1806,11 @@ static int atmel_startup(struct uart_port *port)
return retval;
}
- tasklet_enable(&atmel_port->tasklet);
+ atomic_set(&atmel_port->tasklet_shutdown, 0);
+ tasklet_init(&atmel_port->tasklet_rx, atmel_tasklet_rx_func,
+ (unsigned long)port);
+ tasklet_init(&atmel_port->tasklet_tx, atmel_tasklet_tx_func,
+ (unsigned long)port);
/*
* Initialize DMA (if necessary)
@@ -1833,7 +1858,6 @@ static int atmel_startup(struct uart_port *port)
/* Save current CSR for comparison in atmel_tasklet_func() */
atmel_port->irq_status_prev = atmel_get_lines_status(port);
- atmel_port->irq_status = atmel_port->irq_status_prev;
/*
* Finally, enable the serial port
@@ -1905,29 +1929,36 @@ static void atmel_shutdown(struct uart_port *port)
{
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+ /* Disable interrupts at device level */
+ atmel_uart_writel(port, ATMEL_US_IDR, -1);
+
+ /* Prevent spurious interrupts from scheduling the tasklet */
+ atomic_inc(&atmel_port->tasklet_shutdown);
+
/*
* Prevent any tasklets being scheduled during
* cleanup
*/
del_timer_sync(&atmel_port->uart_timer);
+ /* Make sure that no interrupt is on the fly */
+ synchronize_irq(port->irq);
+
/*
* Clear out any scheduled tasklets before
* we destroy the buffers
*/
- tasklet_disable(&atmel_port->tasklet);
- tasklet_kill(&atmel_port->tasklet);
+ tasklet_kill(&atmel_port->tasklet_rx);
+ tasklet_kill(&atmel_port->tasklet_tx);
/*
* Ensure everything is stopped and
- * disable all interrupts, port and break condition.
+ * disable port and break condition.
*/
atmel_stop_rx(port);
atmel_stop_tx(port);
atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA);
- atmel_uart_writel(port, ATMEL_US_IDR, -1);
-
/*
* Shut-down the DMA.
@@ -2311,10 +2342,6 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
port->irq = pdev->resource[1].start;
port->rs485_config = atmel_config_rs485;
- tasklet_init(&atmel_port->tasklet, atmel_tasklet_func,
- (unsigned long)port);
- tasklet_disable(&atmel_port->tasklet);
-
memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
if (pdata && pdata->regs) {
@@ -2699,6 +2726,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
atmel_port->uart.line = ret;
atmel_serial_probe_fifos(atmel_port, pdev);
+ atomic_set(&atmel_port->tasklet_shutdown, 0);
spin_lock_init(&atmel_port->lock_suspended);
ret = atmel_init_port(atmel_port, pdev);
@@ -2795,7 +2823,8 @@ static int atmel_serial_remove(struct platform_device *pdev)
struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
int ret = 0;
- tasklet_kill(&atmel_port->tasklet);
+ tasklet_kill(&atmel_port->tasklet_rx);
+ tasklet_kill(&atmel_port->tasklet_tx);
device_init_wakeup(&pdev->dev, 0);