diff mbox series

remoteproc: qcom_q6v5_mss: Re-order writes to the IMEM region

Message ID 20240819073020.3291287-1-quic_sibis@quicinc.com
State New
Headers show
Series remoteproc: qcom_q6v5_mss: Re-order writes to the IMEM region | expand

Commit Message

Sibi Sankar Aug. 19, 2024, 7:30 a.m. UTC
Any write access to the IMEM region when the Q6 is setting up XPU
protection on it will result in a XPU violation. Fix this by ensuring
IMEM writes related to the MBA post-mortem logs happen before the Q6
is brought out of reset.

Fixes: 318130cc9362 ("remoteproc: qcom_q6v5_mss: Add MBA log extraction support")
Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
---
 drivers/remoteproc/qcom_q6v5_mss.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Doug Anderson Aug. 19, 2024, 11:40 p.m. UTC | #1
Hi,

On Mon, Aug 19, 2024 at 12:30 AM Sibi Sankar <quic_sibis@quicinc.com> wrote:
>
> Any write access to the IMEM region when the Q6 is setting up XPU
> protection on it will result in a XPU violation. Fix this by ensuring
> IMEM writes related to the MBA post-mortem logs happen before the Q6
> is brought out of reset.
>
> Fixes: 318130cc9362 ("remoteproc: qcom_q6v5_mss: Add MBA log extraction support")
> Signed-off-by: Sibi Sankar <quic_sibis@quicinc.com>
> ---
>  drivers/remoteproc/qcom_q6v5_mss.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)

As discussed offlist, this isn't a perfect fix since writes to this
IMEM could happen by other drivers and those could still cause things
to go boom if they run in parallel with this driver. That being said:
* It seems like a more proper fix needs a coordinated effort between a
device's built-in firmware and the modem firmware. This is difficult /
near impossible to get done properly.
* Even if we do a more proper fix, making this change won't hurt.
* This change will immediately improve things by avoiding the XPU
violation in the most common case.

I've confirmed that the test case I had where things were going boom
is fixed. Thus:

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
diff mbox series

Patch

diff --git a/drivers/remoteproc/qcom_q6v5_mss.c b/drivers/remoteproc/qcom_q6v5_mss.c
index 2a42215ce8e0..32c3531b20c7 100644
--- a/drivers/remoteproc/qcom_q6v5_mss.c
+++ b/drivers/remoteproc/qcom_q6v5_mss.c
@@ -1162,6 +1162,9 @@  static int q6v5_mba_load(struct q6v5 *qproc)
 		goto disable_active_clks;
 	}
 
+	if (qproc->has_mba_logs)
+		qcom_pil_info_store("mba", qproc->mba_phys, MBA_LOG_SIZE);
+
 	writel(qproc->mba_phys, qproc->rmb_base + RMB_MBA_IMAGE_REG);
 	if (qproc->dp_size) {
 		writel(qproc->mba_phys + SZ_1M, qproc->rmb_base + RMB_PMI_CODE_START_REG);
@@ -1172,9 +1175,6 @@  static int q6v5_mba_load(struct q6v5 *qproc)
 	if (ret)
 		goto reclaim_mba;
 
-	if (qproc->has_mba_logs)
-		qcom_pil_info_store("mba", qproc->mba_phys, MBA_LOG_SIZE);
-
 	ret = q6v5_rmb_mba_wait(qproc, 0, 5000);
 	if (ret == -ETIMEDOUT) {
 		dev_err(qproc->dev, "MBA boot timed out\n");