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Subject[PATCH 2/3] dmaengine: at_xdmac: enhance channel errors handling in tasklet
Date
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
+ * just have to scream loudly and try to carry on.
+ */
+ 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 */
+ 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);
+
+ /* 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
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