Re: [PATCH v12 4/9] firmware: qcom: scm: Rework dload mode availability check

From: Mukesh Ojha
Date: Tue Mar 05 2024 - 05:59:37 EST




On 3/3/2024 12:46 AM, Bjorn Andersson wrote:
On Tue, Feb 27, 2024 at 09:23:03PM +0530, Mukesh Ojha wrote:
QCOM_SCM_BOOT_SET_DLOAD_MODE was only valid for very older
target and firmware and for recent targets there is dload
mode tcsr registers available to set the download mode.


I presume this implies that it will always return false, so what's the
actual problem with that? Presumably you want this because it takes
unnecessary time to make that call, if so please say so.

Correct, will add in commit description.

Also, __qcom_scm_is_call_available() usage legacy mode of setting DLOAD mode setting via command which is deprecated long back from Trust zone firmware also it takes or wait statically global mutex lock at the lower level which unnecessary adds time which is of no use.


Content of the patch looks good.

Thanks.

-Mukesh


Regards,
Bjorn

So, it is better to keep it as fallback check instead of
checking its availability and failing it always.

Signed-off-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
Reviewed-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
---
drivers/firmware/qcom/qcom_scm.c | 12 +++++-------
1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index bd6bfdf2d828..3fd89cddba3b 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -540,18 +540,16 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
static void qcom_scm_set_download_mode(bool enable)
{
u32 val = enable ? QCOM_DLOAD_FULLDUMP : QCOM_DLOAD_NODUMP;
- bool avail;
int ret = 0;
- avail = __qcom_scm_is_call_available(__scm->dev,
- QCOM_SCM_SVC_BOOT,
- QCOM_SCM_BOOT_SET_DLOAD_MODE);
- if (avail) {
- ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
- } else if (__scm->dload_mode_addr) {
+ if (__scm->dload_mode_addr) {
ret = qcom_scm_io_rmw(__scm->dload_mode_addr,
QCOM_DLOAD_MASK,
FIELD_PREP(QCOM_DLOAD_MASK, val));
+ } else if (__qcom_scm_is_call_available(__scm->dev,
+ QCOM_SCM_SVC_BOOT,
+ QCOM_SCM_BOOT_SET_DLOAD_MODE)) {
+ ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
} else {
dev_err(__scm->dev,
"No available mechanism for setting download mode\n");
--
2.43.0.254.ga26002b62827