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

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Date:   Tue, 12 Nov 2019 13:22:46 -0800
From:   Elliot Berman <eberman@...eaurora.org>
To:     bjorn.andersson@...aro.org, saiprakash.ranjan@...eaurora.org,
        agross@...nel.org, swboyd@...omium.org
Cc:     Elliot Berman <eberman@...eaurora.org>, tsoni@...eaurora.org,
        sidgup@...eaurora.org, psodagud@...eaurora.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 10/18] firmware: qcom_scm-64: Improve SMC convention detection

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@...eaurora.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)
-- 
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