On 2019-11-15 16:21, Stephen Boyd wrote:
Quoting Elliot Berman (2019-11-12 13:22:46)
diff --git a/drivers/firmware/qcom_scm-64.c
b/drivers/firmware/qcom_scm-64.c
index 977654bb..b82b450 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -302,21 +302,20 @@ int __qcom_scm_hdcp_req(struct device *dev,
struct qcom_scm_hdcp_req *req,
void __qcom_scm_init(void)
{
- u64 cmd;
- struct arm_smccc_res res;
- u32 function = SMCCC_FUNCNUM(QCOM_SCM_SVC_INFO,
QCOM_SCM_INFO_IS_CALL_AVAIL);
-
- /* First try a SMC64 call */
- cmd = ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,
ARM_SMCCC_SMC_64,
- ARM_SMCCC_OWNER_SIP, function);
-
- arm_smccc_smc(cmd, QCOM_SCM_ARGS(1), cmd &
(~BIT(ARM_SMCCC_TYPE_SHIFT)),
- 0, 0, 0, 0, 0, &res);
-
- if (!res.a0 && res.a1)
- qcom_smccc_convention = ARM_SMCCC_SMC_64;
- else
- qcom_smccc_convention = ARM_SMCCC_SMC_32;
+ qcom_smccc_convention = ARM_SMCCC_SMC_64;
+ if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
+ QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
Is this asking if the "is call available function" is available by
using
the is call available function? That is recursive. Isn't that why we
make a manually open coded SMC call to see if it works? If this isn't
going to work we may want to just have a property in DT that tells us
what to do.
Yes. The reason the open coded SMC call was made was because a fast call
works better here. __qcom_scm_is_call_available uses standard call, and
I'll address this in v3.
+ BUG();
This BUG() is new and not mentioned in the commit text. Why can't we
just start failing all scm calls if we can't detect the calling
convention?
Bjorn has requested that the BUG was introduced in v1:
https://lore.kernel.org/patchwork/patch/1148619/#1350062
+out:
+ pr_debug("QCOM SCM SMC Convention: %llu\n",
qcom_smccc_convention);
Maybe pr_info() is more appropriate. PSCI currently prints out the
version info so maybe printing something like "QCOM SCM SMC_64 calling
convention" will be useful for early debugging.
Sure, will do.
Thanks,
Elliot
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