linux-kernel - [RFC PATCH 2/6] firmware: psci: set SMCCC v1.0 conduit and use helpers functions

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Date:   Sun, 19 Apr 2020 17:05:26 +0200
From:   Etienne Carriere <etienne.carriere@...aro.org>
To:     linux-kernel@...r.kernel.org
Cc:     linux-arm-kernel@...ts.infradead.org, james.morse@....com,
        michal.simek@...inx.com, richard.gong@...ux.intel.com,
        lorenzo.pieralisi@....com, mark.rutland@....com,
        jens.wiklander@...aro.org, tee-dev@...ts.linaro.org,
        sudeep.holla@....com,
        Etienne Carriere <etienne.carriere@...aro.org>
Subject: [RFC PATCH 2/6] firmware: psci: set SMCCC v1.0 conduit and use helpers functions

Change PSCI driver to use SMCCC v1.0 helper functions. As PSCI device
is initialized before other devices, it sets the SMCCC conduit used
to SMCCC v1.0 compliant calls and other devices can rely on it.

No functional change in the PSCI device itself.

Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
---
 drivers/firmware/psci/psci.c | 60 +++++-------------------------------
 include/linux/psci.h         |  1 -
 2 files changed, 8 insertions(+), 53 deletions(-)

diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c
index 2937d44b5df4..00bb205cad7c 100644
--- a/drivers/firmware/psci/psci.c
+++ b/drivers/firmware/psci/psci.c
@@ -53,7 +53,6 @@ bool psci_tos_resident_on(int cpu)
 }
 
 struct psci_operations psci_ops = {
-	.conduit = SMCCC_CONDUIT_NONE,
 	.smccc_version = SMCCC_VERSION_1_0,
 };
 
@@ -62,13 +61,9 @@ enum arm_smccc_conduit arm_smccc_1_1_get_conduit(void)
 	if (psci_ops.smccc_version < SMCCC_VERSION_1_1)
 		return SMCCC_CONDUIT_NONE;
 
-	return psci_ops.conduit;
+	return arm_smccc_1_0_get_conduit();
 }
 
-typedef unsigned long (psci_fn)(unsigned long, unsigned long,
-				unsigned long, unsigned long);
-static psci_fn *invoke_psci_fn;
-
 enum psci_function {
 	PSCI_FN_CPU_SUSPEND,
 	PSCI_FN_CPU_ON,
@@ -120,23 +115,14 @@ bool psci_power_state_is_valid(u32 state)
 	return !(state & ~valid_mask);
 }
 
-static unsigned long __invoke_psci_fn_hvc(unsigned long function_id,
-			unsigned long arg0, unsigned long arg1,
-			unsigned long arg2)
+static unsigned long invoke_psci_fn(unsigned long function_id,
+				    unsigned long arg0, unsigned long arg1,
+				    unsigned long arg2)
 {
 	struct arm_smccc_res res;
 
-	arm_smccc_hvc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
-	return res.a0;
-}
+	arm_smccc_1_0_invoke(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
 
-static unsigned long __invoke_psci_fn_smc(unsigned long function_id,
-			unsigned long arg0, unsigned long arg1,
-			unsigned long arg2)
-{
-	struct arm_smccc_res res;
-
-	arm_smccc_smc(function_id, arg0, arg1, arg2, 0, 0, 0, 0, &res);
 	return res.a0;
 }
 
@@ -229,41 +215,11 @@ static unsigned long psci_migrate_info_up_cpu(void)
 			      0, 0, 0);
 }
 
-static void set_conduit(enum arm_smccc_conduit conduit)
-{
-	switch (conduit) {
-	case SMCCC_CONDUIT_HVC:
-		invoke_psci_fn = __invoke_psci_fn_hvc;
-		break;
-	case SMCCC_CONDUIT_SMC:
-		invoke_psci_fn = __invoke_psci_fn_smc;
-		break;
-	default:
-		WARN(1, "Unexpected PSCI conduit %d\n", conduit);
-	}
-
-	psci_ops.conduit = conduit;
-}
-
 static int get_set_conduit_method(struct device_node *np)
 {
-	const char *method;
-
-	pr_info("probing for conduit method from DT.\n");
-
-	if (of_property_read_string(np, "method", &method)) {
-		pr_warn("missing \"method\" property\n");
+	if (of_arm_smccc_1_0_set_conduit(np))
 		return -ENXIO;
-	}
 
-	if (!strcmp("hvc", method)) {
-		set_conduit(SMCCC_CONDUIT_HVC);
-	} else if (!strcmp("smc", method)) {
-		set_conduit(SMCCC_CONDUIT_SMC);
-	} else {
-		pr_warn("invalid \"method\" property: %s\n", method);
-		return -EINVAL;
-	}
 	return 0;
 }
 
@@ -605,9 +561,9 @@ int __init psci_acpi_init(void)
 	pr_info("probing for conduit method from ACPI.\n");
 
 	if (acpi_psci_use_hvc())
-		set_conduit(SMCCC_CONDUIT_HVC);
+		arm_smccc_1_0_set_conduit(SMCCC_CONDUIT_HVC);
 	else
-		set_conduit(SMCCC_CONDUIT_SMC);
+		arm_smccc_1_0_set_conduit(SMCCC_CONDUIT_SMC);
 
 	return psci_probe();
 }
diff --git a/include/linux/psci.h b/include/linux/psci.h
index a67712b73b6c..9de579a1d237 100644
--- a/include/linux/psci.h
+++ b/include/linux/psci.h
@@ -35,7 +35,6 @@ struct psci_operations {
 	int (*affinity_info)(unsigned long target_affinity,
 			unsigned long lowest_affinity_level);
 	int (*migrate_info_type)(void);
-	enum arm_smccc_conduit conduit;
 	enum smccc_version smccc_version;
 };
 
-- 
2.17.1