diff options
| author | Chanho Min <chanho0207@gmail.com> | 2012-02-20 05:24:40 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-02-25 01:50:47 +0400 |
| commit | 6dc01aa65306fe46b7ba38db51fad4ed81c23d00 (patch) | |
| tree | cad255d51a09c900062d9dbd2db07432dc4b5b19 /drivers/tty | |
| parent | b26469a8b139fba11d9336c1c117fafccfa9c7d5 (diff) | |
| download | linux-6dc01aa65306fe46b7ba38db51fad4ed81c23d00.tar.xz | |
amba-pl011/dma: Add check for the residue in DMA callback
In DMA-operated uart, I found that rx data can be taken by the UART
interrupts during the DMA irq handler. pl011_int is occurred just
before it goes inside spin_lock_irq. When it returns to the callback,
DMA buffer already has been flushed. Then, pl011_dma_rx_chars gets
invalid data. So I add check for the residue as the patch bellow.
Signed-off-by: Chanho Min <chanho.min@lge.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/amba-pl011.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 6800f5f26241..cc3ea066c43a 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -827,7 +827,12 @@ static void pl011_dma_rx_callback(void *data) { struct uart_amba_port *uap = data; struct pl011_dmarx_data *dmarx = &uap->dmarx; + struct dma_chan *rxchan = dmarx->chan; bool lastbuf = dmarx->use_buf_b; + struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ? + &dmarx->sgbuf_b : &dmarx->sgbuf_a; + size_t pending; + struct dma_tx_state state; int ret; /* @@ -838,11 +843,21 @@ static void pl011_dma_rx_callback(void *data) * we immediately trigger the next DMA job. */ spin_lock_irq(&uap->port.lock); + /* + * Rx data can be taken by the UART interrupts during + * the DMA irq handler. So we check the residue here. + */ + rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state); + pending = sgbuf->sg.length - state.residue; + BUG_ON(pending > PL011_DMA_BUFFER_SIZE); + /* Then we terminate the transfer - we now know our residue */ + dmaengine_terminate_all(rxchan); + uap->dmarx.running = false; dmarx->use_buf_b = !lastbuf; ret = pl011_dma_rx_trigger_dma(uap); - pl011_dma_rx_chars(uap, PL011_DMA_BUFFER_SIZE, lastbuf, false); + pl011_dma_rx_chars(uap, pending, lastbuf, false); spin_unlock_irq(&uap->port.lock); /* * Do this check after we picked the DMA chars so we don't |