* [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA [not found] <1462896580-11554-1> @ 2016-06-03 11:10 ` Charanya Venkatraman 2016-06-07 10:28 ` Charanya Venkatraman 1 sibling, 0 replies; 10+ messages in thread From: Charanya Venkatraman @ 2016-06-03 11:10 UTC (permalink / raw) To: agross, david.brown, andy.gross, gregkh Cc: jslaby, linux-soc, linux-serial, sricharan, architt, linux-arm-msm, ntelkar, galak, linux-kernel, dmaengine, linux-arm-kernel, absahu, njaigane, Charanya From: Charanya <charanya@codeaurora.org> Avoid data corruption issues that result in CRC erros 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() renables the Rx FIFO interrupt 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> --- drivers/tty/serial/msm_serial.c | 4 ---- 1 file changed, 4 deletions(-) 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); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA @ 2016-06-03 11:10 ` Charanya Venkatraman 0 siblings, 0 replies; 10+ messages in thread From: Charanya Venkatraman @ 2016-06-03 11:10 UTC (permalink / raw) To: linux-arm-kernel From: Charanya <charanya@codeaurora.org> Avoid data corruption issues that result in CRC erros 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() renables the Rx FIFO interrupt 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> --- drivers/tty/serial/msm_serial.c | 4 ---- 1 file changed, 4 deletions(-) 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); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA 2016-06-03 11:10 ` Charanya Venkatraman @ 2016-06-03 15:47 ` Greg KH -1 siblings, 0 replies; 10+ messages in thread From: Greg KH @ 2016-06-03 15:47 UTC (permalink / raw) To: Charanya Venkatraman Cc: agross, david.brown, andy.gross, jslaby, linux-soc, linux-serial, sricharan, architt, linux-arm-msm, ntelkar, galak, linux-kernel, dmaengine, linux-arm-kernel, absahu, njaigane On Fri, Jun 03, 2016 at 04:40:32PM +0530, Charanya Venkatraman wrote: > From: Charanya <charanya@codeaurora.org> This name must match up with your Signed-off-by name :( ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA @ 2016-06-03 15:47 ` Greg KH 0 siblings, 0 replies; 10+ messages in thread From: Greg KH @ 2016-06-03 15:47 UTC (permalink / raw) To: linux-arm-kernel On Fri, Jun 03, 2016 at 04:40:32PM +0530, Charanya Venkatraman wrote: > From: Charanya <charanya@codeaurora.org> This name must match up with your Signed-off-by name :( ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA [not found] <1462896580-11554-1> @ 2016-06-07 10:28 ` Charanya Venkatraman 2016-06-07 10:28 ` Charanya Venkatraman 1 sibling, 0 replies; 10+ messages in thread From: Charanya Venkatraman @ 2016-06-07 10:28 UTC (permalink / raw) To: agross, david.brown, andy.gross, gregkh Cc: jslaby, linux-soc, linux-serial, sricharan, architt, linux-arm-msm, ntelkar, galak, linux-kernel, dmaengine, linux-arm-kernel, absahu, njaigane, Charanya Venkatraman 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(-) 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); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA @ 2016-06-07 10:28 ` Charanya Venkatraman 0 siblings, 0 replies; 10+ messages in thread From: Charanya Venkatraman @ 2016-06-07 10:28 UTC (permalink / raw) To: linux-arm-kernel 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(-) 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); -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA 2016-06-07 10:28 ` Charanya Venkatraman @ 2016-06-07 23:08 ` Stephen Boyd -1 siblings, 0 replies; 10+ messages in thread From: Stephen Boyd @ 2016-06-07 23:08 UTC (permalink / raw) To: Charanya Venkatraman Cc: agross, david.brown, andy.gross, gregkh, jslaby, linux-soc, linux-serial, sricharan, architt, linux-arm-msm, ntelkar, galak, linux-kernel, dmaengine, linux-arm-kernel, absahu, njaigane 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> -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA @ 2016-06-07 23:08 ` Stephen Boyd 0 siblings, 0 replies; 10+ messages in thread From: Stephen Boyd @ 2016-06-07 23:08 UTC (permalink / raw) To: linux-arm-kernel 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> -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA 2016-06-07 10:28 ` Charanya Venkatraman @ 2016-06-09 19:27 ` Andy Gross -1 siblings, 0 replies; 10+ messages in thread From: Andy Gross @ 2016-06-09 19:27 UTC (permalink / raw) To: Charanya Venkatraman Cc: agross, david.brown, gregkh, jslaby, linux-soc, linux-serial, sricharan, architt, linux-arm-msm, ntelkar, galak, linux-kernel, dmaengine, linux-arm-kernel, absahu, njaigane 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> ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH v3] tty:serial:msm:Do not restore Rx interrupts in DMA @ 2016-06-09 19:27 ` Andy Gross 0 siblings, 0 replies; 10+ messages in thread From: Andy Gross @ 2016-06-09 19:27 UTC (permalink / raw) To: linux-arm-kernel 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> ^ permalink raw reply [flat|nested] 10+ messages in thread
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2016-06-03 11:10 ` [PATCH v2] tty:serial:msm:Do not restore Rx interrupts in DMA Charanya Venkatraman
2016-06-03 11:10 ` Charanya Venkatraman
2016-06-03 15:47 ` Greg KH
2016-06-03 15:47 ` Greg KH
2016-06-07 10:28 ` [PATCH v3] " Charanya Venkatraman
2016-06-07 10:28 ` Charanya Venkatraman
2016-06-07 23:08 ` Stephen Boyd
2016-06-07 23:08 ` Stephen Boyd
2016-06-09 19:27 ` Andy Gross
2016-06-09 19:27 ` Andy Gross
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