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SubjectRe: [PATCH 2/3] dmaengine: at_xdmac: enhance channel errors handling in tasklet
On 05-02-19, 12:03, Nicolas Ferre wrote:
> Complement the identification of errors with stoping the channel and
> dumping the descriptor that led to the error case.
>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
> ---
> drivers/dma/at_xdmac.c | 43 ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 37 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
> index 37a269420435..ec7a29d8e448 100644
> --- a/drivers/dma/at_xdmac.c
> +++ b/drivers/dma/at_xdmac.c
> @@ -1575,6 +1575,41 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan)
> dmaengine_desc_get_callback_invoke(txd, NULL);
> }
>
> +static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
> +{
> + struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device);
> + struct at_xdmac_desc *bad_desc;
> +
> + /*
> + * The descriptor currently at the head of the active list is
> + * broked. Since we don't have any way to report errors, we'll

You meant borked or broken...

> + * just have to scream loudly and try to carry on.

should we carry on or abort..?

> + */
> + if (atchan->irq_status & AT_XDMAC_CIS_RBEIS)
> + dev_err(chan2dev(&atchan->chan), "read bus error!!!");
> + if (atchan->irq_status & AT_XDMAC_CIS_WBEIS)
> + dev_err(chan2dev(&atchan->chan), "write bus error!!!");
> + if (atchan->irq_status & AT_XDMAC_CIS_ROIS)
> + dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
> +
> + spin_lock_bh(&atchan->lock);
> + /* Channel must be disabled first as it's not done automatically */
> + at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask);
> + while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask)
> + cpu_relax();
> + bad_desc = list_first_entry(&atchan->xfers_list,
> + struct at_xdmac_desc,
> + xfer_node);
> + spin_unlock_bh(&atchan->lock);
> + /* Print bad descriptor's details if needed */

Well this is not great to look and read at, please do consider adding
empty line before comments or logical blocks..

> + dev_dbg(chan2dev(&atchan->chan),
> + "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n",
> + __func__, &bad_desc->lld.mbr_sa, &bad_desc->lld.mbr_da,
> + bad_desc->lld.mbr_ubc);

not dev_err?

> +
> + /* Then continue with usual descriptor management */
> +}
> +
> static void at_xdmac_tasklet(unsigned long data)
> {
> struct at_xdmac_chan *atchan = (struct at_xdmac_chan *)data;
> @@ -1594,12 +1629,8 @@ static void at_xdmac_tasklet(unsigned long data)
> || (atchan->irq_status & error_mask)) {
> struct dma_async_tx_descriptor *txd;
>
> - if (atchan->irq_status & AT_XDMAC_CIS_RBEIS)
> - dev_err(chan2dev(&atchan->chan), "read bus error!!!");
> - if (atchan->irq_status & AT_XDMAC_CIS_WBEIS)
> - dev_err(chan2dev(&atchan->chan), "write bus error!!!");
> - if (atchan->irq_status & AT_XDMAC_CIS_ROIS)
> - dev_err(chan2dev(&atchan->chan), "request overflow error!!!");
> + if (atchan->irq_status & error_mask)
> + at_xdmac_handle_error(atchan);
>
> spin_lock(&atchan->lock);
> desc = list_first_entry(&atchan->xfers_list,
> --
> 2.17.1

--
~Vinod

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