| Message ID | 1465295321-10506-1-git-send-email-charanya@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 06/07, Charanya Venkatraman wrote: > Avoid data corruption issues that result in CRC errors during file > transfers over serial ports at higher baud rates. > > The current msm_serial driver masks the FIFO Rx interrupts in > msm_start_rx_dma() since Rx FIFO interrupts are not required in DMA > mode. However, msm_complete_rx_dma() re-enables the Rx FIFO interrupts > which could cause RXSTALE event to be processed when a TXLEV interrupt > occurs. > > The following is the sequence of events that could occur resulting in > data corruption. > > msm_start_rx_dma -> msm_complete_rx_dma --> > spin_unlock_irqrestore(&port->lock) --> > msm_uart_irq()(For TXLEV interrupt) --> msm_handle_rx_dm() (Read from > FIFO resulting in data corruption) > > The patch fixes the issue by not restoring the RXLEV and RXSTALE > interrupts in msm_complete_rx_dma(). These interrupts are required only > in FIFO mode. > > Signed-off-by: Charanya Venkatraman <charanya@codeaurora.org> > --- Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
On Tue, Jun 07, 2016 at 03:58:41PM +0530, Charanya Venkatraman wrote: > Avoid data corruption issues that result in CRC errors during file > transfers over serial ports at higher baud rates. > > The current msm_serial driver masks the FIFO Rx interrupts in > msm_start_rx_dma() since Rx FIFO interrupts are not required in DMA > mode. However, msm_complete_rx_dma() re-enables the Rx FIFO interrupts > which could cause RXSTALE event to be processed when a TXLEV interrupt > occurs. > > The following is the sequence of events that could occur resulting in > data corruption. > > msm_start_rx_dma -> msm_complete_rx_dma --> > spin_unlock_irqrestore(&port->lock) --> > msm_uart_irq()(For TXLEV interrupt) --> msm_handle_rx_dm() (Read from > FIFO resulting in data corruption) > > The patch fixes the issue by not restoring the RXLEV and RXSTALE > interrupts in msm_complete_rx_dma(). These interrupts are required only > in FIFO mode. > > Signed-off-by: Charanya Venkatraman <charanya@codeaurora.org> Acked-by: Andy Gross <andy.gross@linaro.org>
diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c index b7d80bd..646aa3f 100644 --- a/drivers/tty/serial/msm_serial.c +++ b/drivers/tty/serial/msm_serial.c @@ -388,10 +388,6 @@ static void msm_complete_rx_dma(void *args) val &= ~dma->enable_bit; msm_write(port, val, UARTDM_DMEN); - /* Restore interrupts */ - msm_port->imr |= UART_IMR_RXLEV | UART_IMR_RXSTALE; - msm_write(port, msm_port->imr, UART_IMR); - if (msm_read(port, UART_SR) & UART_SR_OVERRUN) { port->icount.overrun++; tty_insert_flip_char(tport, 0, TTY_OVERRUN);
Avoid data corruption issues that result in CRC errors during file transfers over serial ports at higher baud rates. The current msm_serial driver masks the FIFO Rx interrupts in msm_start_rx_dma() since Rx FIFO interrupts are not required in DMA mode. However, msm_complete_rx_dma() re-enables the Rx FIFO interrupts which could cause RXSTALE event to be processed when a TXLEV interrupt occurs. The following is the sequence of events that could occur resulting in data corruption. msm_start_rx_dma -> msm_complete_rx_dma --> spin_unlock_irqrestore(&port->lock) --> msm_uart_irq()(For TXLEV interrupt) --> msm_handle_rx_dm() (Read from FIFO resulting in data corruption) The patch fixes the issue by not restoring the RXLEV and RXSTALE interrupts in msm_complete_rx_dma(). These interrupts are required only in FIFO mode. Signed-off-by: Charanya Venkatraman <charanya@codeaurora.org> --- Changes in v2: - Make commit message more clearer. Changes in v3: - Fix typos in commit message. drivers/tty/serial/msm_serial.c | 4 ---- 1 file changed, 4 deletions(-)