[PATCH v2 10/18] firmware: qcom_scm-64: Improve SMC convention detection

Elliot Berman
2019-11-12T21:24:08Z

Improve the calling convention detection to use
__qcom_scm_is_call_available() and not blindly assume 32-bit mode if
the checks fails.

Signed-off-by: Elliot Berman <eberman@codeaurora.org>
---
drivers/firmware/qcom_scm-64.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

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)
+ goto out;
+
+ qcom_smccc_convention = ARM_SMCCC_SMC_32;
+ if (__qcom_scm_is_call_available(NULL, QCOM_SCM_SVC_INFO,
+ QCOM_SCM_INFO_IS_CALL_AVAIL) == 1)
+ goto out;
+
+ qcom_smccc_convention = -1;
+ BUG();
+out:
+ pr_debug("QCOM SCM SMC Convention: %llu\n", qcom_smccc_convention);
}

bool __qcom_scm_pas_supported(struct device *dev, u32 peripheral)