On Sat, Oct 05, 2024 at 07:31:49PM GMT, Kuldeep Singh wrote:
Please shorten the subject a bit, perhaps:
"firmware: qcom: scm: Improve unsupported SHM bridge detection"
> From: Qingqing Zhou <quic_qqzhou@xxxxxxxxxxx>
>
> Currently for enabling shm bridge, QTEE will return 0 and put error 4 into
s/for/when/
> result[0] to qcom_scm for unsupported platform, tzmem will consider this
> as an unknown error not the unsupported case on the platform.
>
> Error log:
> [ 0.177224] qcom_scm firmware:scm: error (____ptrval____): Failed to enable the TrustZone memory allocator
> [ 0.177244] qcom_scm firmware:scm: probe with driver qcom_scm failed with error 4
>
> Change the function call qcom_scm_shm_bridge_enable() to remap this
> result[0] into the unsupported error and then tzmem can consider this as
> unsupported case instead of reporting an error.
>
Sounds like we want a Fixes tag here.
> Signed-off-by: Qingqing Zhou <quic_qqzhou@xxxxxxxxxxx>
> Co-developed-by: Kuldeep Singh <quic_kuldsing@xxxxxxxxxxx>
> Signed-off-by: Kuldeep Singh <quic_kuldsing@xxxxxxxxxxx>
> ---
> drivers/firmware/qcom/qcom_scm.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
> index 10986cb11ec0..620313359042 100644
> --- a/drivers/firmware/qcom/qcom_scm.c
> +++ b/drivers/firmware/qcom/qcom_scm.c
> @@ -111,6 +111,10 @@ enum qcom_scm_qseecom_tz_cmd_info {
> QSEECOM_TZ_CMD_INFO_VERSION = 3,
> };
>
> +enum qcom_scm_shm_bridge_result {
> + SHMBRIDGE_RESULT_NOTSUPP = 4,
> +};
This is not an enumeration, but a fixed defined constant. Please use
#define.
> +
> #define QSEECOM_MAX_APP_NAME_SIZE 64
>
> /* Each bit configures cold/warm boot address for one of the 4 CPUs */
> @@ -1361,6 +1365,8 @@ EXPORT_SYMBOL_GPL(qcom_scm_lmh_dcvsh_available);
>
> int qcom_scm_shm_bridge_enable(void)
> {
> + int ret;
> +
> struct qcom_scm_desc desc = {
> .svc = QCOM_SCM_SVC_MP,
> .cmd = QCOM_SCM_MP_SHM_BRIDGE_ENABLE,
> @@ -1373,7 +1379,11 @@ int qcom_scm_shm_bridge_enable(void)
> QCOM_SCM_MP_SHM_BRIDGE_ENABLE))
> return -EOPNOTSUPP;
>
> - return qcom_scm_call(__scm->dev, &desc, &res) ?: res.result[0];
> + ret = qcom_scm_call(__scm->dev, &desc, &res);
> + if (!ret && res.result[0] == SHMBRIDGE_RESULT_NOTSUPP)
> + return -EOPNOTSUPP;
> +
> + return ret ?: res.result[0];
I'd prefer, with the additional check, that you'd structure it like this:
if (ret)
return ret;
if (res.result[0] == SHMBRIDGE_RESULT_NOTSUPP)
return -EOPNOTSUPP;
return res.result[0];
That way we deal with SCM-call errors first, otherwise we inspect and
act on the returned data.
That said, the return value of this function, if non-zero, will trickle
back to and be returned from qcom_scm_probe(), where Linux expects to
see a valid error code. Are there any other result[0] values we should
handle, which would allow us to end this function with "return 0"?
Regards,
Bjorn
> }
> EXPORT_SYMBOL_GPL(qcom_scm_shm_bridge_enable);
>
> --
> 2.34.1
>
