Messages in this thread Patch in this message | | | From | Haavard Skinnemoen <> | Subject | [PATCH -mm] atmel_serial dma: Misc fixes and cleanups | Date | Mon, 28 Jan 2008 12:48:50 +0100 |
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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 <hskinnemoen@atmel.com> --- 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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