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Subject[PATCH 1/2] dma: cppi41: redo descriptor collection in abort case
Date
Most of the logic here is try and error since what actually happens does
not match the trm or I miss read it.
My first assumption was that the queue on which the tear-down descriptor
completes (their own complete queue vs "active descriptor" complete
queue) depends on the transfer direction. This seems not to be true
because I manage to trigger
| WARN_ON(c->desc_phys != desc_phys);
and the other few were fine means the tear-down descriptor was valid but
on different queue.

This patch changes the logic here to look on both queues for the
descriptor.

Cc: Daniel Mack <zonque@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
drivers/dma/cppi41.c | 41 ++++++++++++++++-------------------------
1 file changed, 16 insertions(+), 25 deletions(-)

diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c
index 42d1c58..272969c 100644
--- a/drivers/dma/cppi41.c
+++ b/drivers/dma/cppi41.c
@@ -563,36 +563,27 @@ static int cppi41_tear_down_chan(struct cppi41_channel *c)
c->td_retry = 100;
}

- if (!c->td_seen) {
+ if (!c->td_seen || !c->td_desc_seen) {
unsigned td_comp_queue;

- if (c->is_tx)
- td_comp_queue = cdd->td_queue.complete;
- else
- td_comp_queue = c->q_comp_num;
+ desc_phys = cppi41_pop_desc(cdd, cdd->td_queue.complete);
+ if (!desc_phys)
+ desc_phys = cppi41_pop_desc(cdd, c->q_comp_num);

- desc_phys = cppi41_pop_desc(cdd, td_comp_queue);
- if (desc_phys) {
- __iormb();
+ if (desc_phys == c->desc_phys) {
+ c->td_desc_seen = 1;
+
+ } else if (desc_phys == td_desc_phys) {
+ u32 pd0;

- if (desc_phys == td_desc_phys) {
- u32 pd0;
- pd0 = td->pd0;
- WARN_ON((pd0 >> DESC_TYPE) != DESC_TYPE_TEARD);
- WARN_ON(!c->is_tx && !(pd0 & TD_DESC_IS_RX));
- WARN_ON((pd0 & 0x1f) != c->port_num);
- } else {
- WARN_ON_ONCE(1);
- }
- c->td_seen = 1;
- }
- }
- if (!c->td_desc_seen) {
- desc_phys = cppi41_pop_desc(cdd, c->q_comp_num);
- if (desc_phys) {
__iormb();
- WARN_ON(c->desc_phys != desc_phys);
- c->td_desc_seen = 1;
+ pd0 = td->pd0;
+ WARN_ON((pd0 >> DESC_TYPE) != DESC_TYPE_TEARD);
+ WARN_ON(!c->is_tx && !(pd0 & TD_DESC_IS_RX));
+ WARN_ON((pd0 & 0x1f) != c->port_num);
+ c->td_seen = 1;
+ } else if (desc_phys) {
+ WARN_ON_ONCE(1);
}
}
c->td_retry--;
--
1.8.4.rc3


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