Re: [PATCH 11/15] tty: msm_serial: use dmaengine_prep_slave_sg()

[Jiri Slaby]

On 19. 04. 24, 9:43, Jiri Slaby wrote:
> On 17. 04. 24, 14:45, Marek Szyprowski wrote:
> > I alse tried to change the "if (dma->mapped)" check in msm_start_tx() to:
> >
> > 1. if (dma->tx_sg.length)
> >
> > 2. if (dma->tx_sg.page_link & ~SG_PAGE_LINK_MASK)
> >
> > but none of the above worked what is really strange and incomprehensible
> > for me.
>
> Aaaah, nevermind, what about this?
>
> Two bugs:
> 1) dma_map_sg() returns the number of mapped entries. Not zero!
> 2) And I forgot to zero tx_sg in case of error.
>
> --- a/drivers/tty/serial/msm_serial.c
> +++ b/drivers/tty/serial/msm_serial.c
> @@ -506,8 +506,8 @@ static int msm_handle_tx_dma(struct msm_port 
> *msm_port, unsigned int count)
>          kfifo_dma_out_prepare(&tport->xmit_fifo, &dma->tx_sg, 1, count);
>
>          ret = dma_map_sg(port->dev, &dma->tx_sg, 1, dma->dir);
> -       if (ret)
> -               return ret;
> +       if (!ret)

Still wrong, ret = -EIO missing in here.

> +               goto zero_out;
>
>          dma->desc = dmaengine_prep_slave_sg(dma->chan, &dma->tx_sg, 1,
>                                                  DMA_MEM_TO_DEV,
> @@ -548,6 +548,7 @@ static int msm_handle_tx_dma(struct msm_port 
> *msm_port, unsigned int count)
>          return 0;
>   unmap:
>          dma_unmap_sg(port->dev, &dma->tx_sg, 1, dma->dir);
> +zero_out:
>          sg_init_table(&dma->tx_sg, 1);
>          return ret;
>   }
>
>
> thanks,

--
js
suse labs