On 3/6/2019 6:30 PM, Adrian Hunter wrote:
On 2/03/19 7:20 AM, Sowjanya Komatineni wrote:
This patch adds a quirk for setting CMD_TIMING to 1 in descriptor
for DCMD with R1B response type to allow the command to be sent to
device during data activity or busy time.
Tegra186 CQHCI host has bug where it selects DATA_PRESENT_SELECT
to 1 by CQHCI controller for DCMDs with R1B response type and
since DCMD does not trigger any data transfer, DCMD task complete
happens leaving the DATA FSM of host controller in wait state for
data.
This effects the data transfer task issued after R1B DCMD task
and no interrupt is generated for the data transfer task.
SW WAR for this issue is to set CMD_TIMING bit to 1 in DCMD task
descriptor and as DCMD task descriptor preparation is done by
cqhci driver, this patch adds cqequirk to handle this.
Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
---
drivers/mmc/host/cqhci.c | 5 ++++-
drivers/mmc/host/cqhci.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/cqhci.c b/drivers/mmc/host/cqhci.c
index a8af682a9182..b34c07125f32 100644
--- a/drivers/mmc/host/cqhci.c
+++ b/drivers/mmc/host/cqhci.c
@@ -521,7 +521,10 @@ static void cqhci_prep_dcmd_desc(struct mmc_host *mmc,
} else {
if (mrq->cmd->flags & MMC_RSP_R1B) {
resp_type = 0x3;
- timing = 0x0;
+ if (cq_host->quirks & CQHCI_QUIRK_CMD_TIMING_R1B_DCMD)
+ timing = 0x1;
+ else
+ timing = 0x0;
I was thinking it would be nice if there was a generic way for drivers to
make changes to descriptors before a task is started. Currently there is
host->ops->write_l() which would make it possible by checking for CQHCI_TDBR
register and, in this case, the DCMD tag. We would need to export
get_desc(), perhaps rename it cqhci_get_desc() and put it in cqhci.h since
it is an inline function.
We take spin_lock_irqsave after the descriptor is prepared and before
writing to TDBR.
Not sure but tomorrow this may become a limitation for drivers to make
changes to
descriptors if they edit descriptors in host->ops->write_l() call.
Though in this case it is not required here.
Alternatively we could add host->ops for descriptor preparation.
Both ways sounds good to me.
But maybe adding a host->ops for descriptor preparation is better way to go,
since that will be the right interface exposed to make changes to
descriptors.
What do people think?
} else {
resp_type = 0x2;
timing = 0x1;
diff --git a/drivers/mmc/host/cqhci.h b/drivers/mmc/host/cqhci.h
index 9e68286a07b4..f96d8565cc07 100644
--- a/drivers/mmc/host/cqhci.h
+++ b/drivers/mmc/host/cqhci.h
@@ -170,6 +170,7 @@ struct cqhci_host {
u32 quirks;
#define CQHCI_QUIRK_SHORT_TXFR_DESC_SZ 0x1
+#define CQHCI_QUIRK_CMD_TIMING_R1B_DCMD 0x2
bool enabled;
bool halted;
