Fix some issues identified by Andrew Morton:
* Kill unused PDC_RX_BUF() and PDC_RX_SWITCH() macros
* Simplify TX circ buffer management a bit.
* Don't open-code min()
* Add comment explaining why "count = head - tail" will not cause
wraparound problems.
Also, s/SERIAL_XMIT_SIZE/UART_XMIT_SIZE/ since the latter is what the
serial core circ macros use.
Signed-off-by: Haavard Skinnemoen <[EMAIL PROTECTED]>
---
Please fold into atmel_serial-add-dma-support.patch, or let me know if
you want a replacement for that patch.
drivers/serial/atmel_serial.c | 27 +++++++++++++--------------
1 files changed, 13 insertions(+), 14 deletions(-)
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c
index 63505cc..62654ab 100644
--- a/drivers/serial/atmel_serial.c
+++ b/drivers/serial/atmel_serial.c
@@ -114,7 +114,7 @@ static void (*atmel_close_hook)(struct uart_port *);
struct atmel_dma_buffer {
unsigned char *buf;
dma_addr_t dma_addr;
- size_t dma_size;
+ unsigned int dma_size;
unsigned int ofs;
};
@@ -150,9 +150,6 @@ struct atmel_uart_port {
static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];
-#define PDC_RX_BUF(port) &(port)->pdc_rx[(port)->pdc_rx_idx]
-#define PDC_RX_SWITCH(port) (port)->pdc_rx_idx = !(port)->pdc_rx_idx
-
#ifdef SUPPORT_SYSRQ
static struct console atmel_console;
#endif
@@ -567,8 +564,7 @@ static void atmel_tx_dma(struct uart_port *port)
int count;
xmit->tail += pdc->ofs;
- if (xmit->tail >= SERIAL_XMIT_SIZE)
- xmit->tail -= SERIAL_XMIT_SIZE;
+ xmit->tail &= UART_XMIT_SIZE - 1;
port->icount.tx += pdc->ofs;
pdc->ofs = 0;
@@ -583,10 +579,7 @@ static void atmel_tx_dma(struct uart_port *port)
pdc->dma_size,
DMA_TO_DEVICE);
- if (xmit->tail < xmit->head)
- count = xmit->head - xmit->tail;
- else
- count = SERIAL_XMIT_SIZE - xmit->tail;
+ count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
pdc->ofs = count;
UART_PUT_TPR(port, pdc->dma_addr + xmit->tail);
@@ -701,14 +694,20 @@ static void atmel_rx_from_dma(struct uart_port *port)
* ENDRX bit as well, so that we can safely re-enable
* all interrupts below.
*/
- if (head >= pdc->dma_size)
- head = pdc->dma_size;
+ head = min(head, pdc->dma_size);
if (likely(head != tail)) {
dma_sync_single_for_cpu(port->dev, pdc->dma_addr,
pdc->dma_size, DMA_FROM_DEVICE);
+ /*
+ * head will only wrap around when we recycle
+ * the DMA buffer, and when that happens, we
+ * explicitly set tail to 0. So head will
+ * always be greater than tail.
+ */
count = head - tail;
+
tty_insert_flip_string(tty, pdc->buf + pdc->ofs, count);
dma_sync_single_for_device(port->dev, pdc->dma_addr,
@@ -859,9 +858,9 @@ static int atmel_startup(struct uart_port *port)
pdc->buf = xmit->buf;
pdc->dma_addr = dma_map_single(port->dev,
pdc->buf,
- SERIAL_XMIT_SIZE,
+ UART_XMIT_SIZE,
DMA_TO_DEVICE);
- pdc->dma_size = SERIAL_XMIT_SIZE;
+ pdc->dma_size = UART_XMIT_SIZE;
pdc->ofs = 0;
}
--
1.5.3.8
--
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