2020-01-22 08:26:05

by Arun Kumar Neelakantam

Subject: [PATCH] soc: qcom: aoss: Read back before triggering the IRQ

In some device memory used by msm_qmp, there can be an early ack of a
write to memory succeeding. This may cause the outgoing interrupt to be
triggered before the msgram reflects the write.

Add a readback to ensure the data is flushed to device memory before
triggering the ipc interrupt.

Signed-off-by: Arun Kumar Neelakantam <[email protected]>
---
drivers/soc/qcom/qcom_aoss.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
index fe79661..f43a2e0 100644
--- a/drivers/soc/qcom/qcom_aoss.c
+++ b/drivers/soc/qcom/qcom_aoss.c
@@ -225,6 +225,7 @@ static bool qmp_message_empty(struct qmp *qmp)
static int qmp_send(struct qmp *qmp, const void *data, size_t len)
{
long time_left;
+ size_t tlen;
int ret;

if (WARN_ON(len + sizeof(u32) > qmp->size))
@@ -239,6 +240,9 @@ static int qmp_send(struct qmp *qmp, const void *data, size_t len)
__iowrite32_copy(qmp->msgram + qmp->offset + sizeof(u32),
data, len / sizeof(u32));
writel(len, qmp->msgram + qmp->offset);
+
+ /* Read back len to confirm data written in message RAM */
+ tlen = readl(qmp->msgram + qmp->offset);
qmp_kick(qmp);

time_left = wait_event_interruptible_timeout(qmp->event,
--
1.9.1

2020-02-12 06:34:11

by Bjorn Andersson

Subject: Re: [PATCH] soc: qcom: aoss: Read back before triggering the IRQ

On Wed 22 Jan 00:24 PST 2020, Arun Kumar Neelakantam wrote:

> In some device memory used by msm_qmp, there can be an early ack of a
> write to memory succeeding. This may cause the outgoing interrupt to be
> triggered before the msgram reflects the write.
>
> Add a readback to ensure the data is flushed to device memory before
> triggering the ipc interrupt.
>
> Signed-off-by: Arun Kumar Neelakantam <[email protected]>

Applied

Thanks,
Bjorn

> ---
> drivers/soc/qcom/qcom_aoss.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/soc/qcom/qcom_aoss.c b/drivers/soc/qcom/qcom_aoss.c
> index fe79661..f43a2e0 100644
> --- a/drivers/soc/qcom/qcom_aoss.c
> +++ b/drivers/soc/qcom/qcom_aoss.c
> @@ -225,6 +225,7 @@ static bool qmp_message_empty(struct qmp *qmp)
> static int qmp_send(struct qmp *qmp, const void *data, size_t len)
> {
> long time_left;
> + size_t tlen;
> int ret;
>
> if (WARN_ON(len + sizeof(u32) > qmp->size))
> @@ -239,6 +240,9 @@ static int qmp_send(struct qmp *qmp, const void *data, size_t len)
> __iowrite32_copy(qmp->msgram + qmp->offset + sizeof(u32),
> data, len / sizeof(u32));
> writel(len, qmp->msgram + qmp->offset);
> +
> + /* Read back len to confirm data written in message RAM */
> + tlen = readl(qmp->msgram + qmp->offset);
> qmp_kick(qmp);
>
> time_left = wait_event_interruptible_timeout(qmp->event,
> --
> 1.9.1