On 9/7/2023 12:02 PM, Sricharan Ramabadhran wrote:
<snip ..>
+ int ret;
+ struct qcom_scm_desc desc = {
+ .svc = QCOM_SCM_SVC_BOOT,
+ .cmd = QCOM_SCM_BOOT_SDI_CONFIG,
+ .args[0] = 1, /* Disable watchdog debug */
+ .args[1] = 0, /* Disable SDI */
+ .arginfo = QCOM_SCM_ARGS(2),
+ .owner = ARM_SMCCC_OWNER_SIP,
+ };
+ struct qcom_scm_res res;
+
+ ret = qcom_scm_clk_enable();
+ if (ret)
+ return ret;
+ ret = qcom_scm_call(__scm->dev, &desc, &res);
Would you not be wanting this call to be atomic ?
This is implemented based off the downstream 5.4 kernel as I dont have
the SCM docs
so I dont know if its even supported in the atomic version.
Ok,.
Well, Kernel version does not guarantees us whether certain things
are supported or not in the firmware and it is not bound to any
particular firmware version;
So, whatever firmware version it is running with, we should try to
support.
Should we implement certain kind of call, if fastcall(atomic) is
supported go-ahead otherwise fallback to slowcalls (interruptible)
calls, but this is completely out of the context of this patch.
I replied on older thread, was not in CC here, just saw this.
Agree, atomic api is out of this context and we could take it up
separately.
+
+ qcom_scm_clk_disable();
+
+ return ret ? : res.result[0];
+}
+
static int __qcom_scm_set_dload_mode(struct device *dev, bool
enable)
{
struct qcom_scm_desc desc = {
@@ -1468,6 +1491,12 @@ static int qcom_scm_probe(struct
platform_device *pdev)
if (download_mode)
qcom_scm_set_download_mode(true);
+ /*
+ * Disable SDI if indicated by DT that it is enabled by default.
+ */
+ if (of_property_read_bool(pdev->dev.of_node,
"qcom,sdi-enabled"))
+ qcom_scm_disable_sdi();
Why don't we do this call in qcom_scm_shutdown()
also does it not conflict with above download_mode
we have enabled download mode but disabling SDI
means (hard reset) and will not be collecting
crash dump?
Because doing it in SCM removal is too late, what if we have a WDT
assertion and not a
regular reboot?
It would mean that the board will get stuck in the debug mode which is
not useful for users and
requires the power to be pulled in order to boot normally again.
Agree.
For IPQ chipsets, SDI bit is used like below,
For abnormal resets (like WDT), should be set '1' for valid dump
collection.
For reboot, should be cleared to '0' to avoid dump collection which
is not required in this case.
For HLOS panic, is a don't care, dumps always get collected and
firmware takes care of clearing the SDI bit.
Mukesh, Can you confirm if its same for msm also ?
Yes, it is same in MSM as well.
-Mukesh
Just a wild guess..
Can we check if this call __qcom_scm_is_call_available() helps
to determine, if the certain soc has this SCM calls supported
and if it is there it can be disabled.
__qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_BOOT,
QCOM_SCM_BOOT_SDI_CONFIG)
Yes, as i mentioned in other thread, checking using
qcom_scm_is_call_available is better. That said, would require
testing on all IPQ/MSM socs to confirm if firmware supports it.
I am not sure about the download mode, this is where insight from QCA
really help as I am
doing this with very limited docs.
Download mode would not be reflected unless it is debug
board, whatever you write will not be allowed if it is a
secure device.
Yes, 'download mode' bit is similar, but that is used by the firmware
to determining whether to collect dumps on non-secure boards.
Specifically, 'SDI bit' on some socs is used by firmware to determine
if boot is happening from a 'abnormal crash', hence put DDR to
self-refresh etc for valid dumps.
Regards,
Sricharan
