Re: [PATCH] uart: mediatek: fix memory corruption issue

zhiyong tao
2021-07-22T09:13:22Z

On Wed, 2021-07-14 at 01:20 +0300, Andy Shevchenko wrote:
>
>
> On Saturday, July 10, 2021, Zhiyong Tao <zhiyong.tao@mediatek.com>
> wrote:
>
>
> Please, use “serial: 8260_mtk:” prefix.

==> Hi Andy,

Thanks for your suggestion.
we will change it in the next version.
>
> This patch is used to fix memory
>
>
>
> This is completely confusing start of the sentence. The form of “be
> used to” strongly suggests two things: 1) it was a patch to fix
> something; 2) it is not used anymore and never considered to be used
> again,
>
>
> Besides that Submitting Patches document highly recommends to avoid
> sentences that starts with “this patch”.
>

==>We will change the commit message as "Fix uart corruption issue when
rx power off "in the next version.

Thanks.
>
> corruption issue when rx power off.
> 1. add spin lock in mtk8250_dma_rx_complete function in APDMA
> mode.
> 2. add processing mechanism which count value is 0
>
> Signed-off-by: Zhiyong Tao <zhiyong.tao@mediatek.com>
> ---
> drivers/tty/serial/8250/8250_mtk.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_mtk.c
> b/drivers/tty/serial/8250/8250_mtk.c
> index f7d3023f860f..09f7d2166315 100644
> --- a/drivers/tty/serial/8250/8250_mtk.c
> +++ b/drivers/tty/serial/8250/8250_mtk.c
> @@ -91,12 +91,15 @@ static void mtk8250_dma_rx_complete(void
> *param)
> struct mtk8250_data *data = up->port.private_data;
> struct tty_port *tty_port = &up->port.state->port;
> struct dma_tx_state state;
> - int copied, total, cnt;
> + unsigned int copied, total, cnt;
> unsigned char *ptr;
> + unsigned long flags;
>
> if (data->rx_status == DMA_RX_SHUTDOWN)
> return;
>
> + spin_lock_irqsave(&up->port.lock, flags);
> +
> dmaengine_tx_status(dma->rxchan, dma->rx_cookie,
> &state);
> total = dma->rx_size - state.residue;
> cnt = total;
> @@ -104,9 +107,11 @@ static void mtk8250_dma_rx_complete(void
> *param)
> if ((data->rx_pos + cnt) > dma->rx_size)
> cnt = dma->rx_size - data->rx_pos;
>
> - ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
> - copied = tty_insert_flip_string(tty_port, ptr, cnt);
> - data->rx_pos += cnt;
> + if (cnt != 0) {
> + ptr = (unsigned char *)(data->rx_pos +
> dma->rx_buf);
> + copied = tty_insert_flip_string(tty_port, ptr,
> cnt);
> + data->rx_pos += cnt;
> + }
>
> if (total > cnt) {
> ptr = (unsigned char *)(dma->rx_buf);
> @@ -120,6 +125,8 @@ static void mtk8250_dma_rx_complete(void
> *param)
> tty_flip_buffer_push(tty_port);
>
> mtk8250_rx_dma(up);
> +
> + spin_unlock_irqrestore(&up->port.lock, flags);
> }
>
> static void mtk8250_rx_dma(struct uart_8250_port *up)