linux-kernel - [RFC PATCH 6/6] firmware: zynqmp: use SMCCC v1.0 helper functions

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Date:   Sun, 19 Apr 2020 17:05:30 +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 6/6] firmware: zynqmp: use SMCCC v1.0 helper functions

Change Xilinx Zynmp driver to use Arm SMCCC v1.0 helper functions
and ensure platform consistency on SMCCC conduit method.

Main functional change is that SMCCC conduit method for ZynqMP
firmware must be consistent with conduit methods registered by
PSCI device that is early probed.

Another functional change is an addition info trace emitted by the
device probe sequence: "probing for conduit method from DT.".

Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
---
 drivers/firmware/xilinx/zynqmp.c | 87 ++++----------------------------
 1 file changed, 9 insertions(+), 78 deletions(-)

diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 41b65164a367..1fdc468c9204 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/drivers/firmware/xilinx/zynqmp.c
@@ -63,51 +63,11 @@ static int zynqmp_pm_ret_code(u32 ret_status)
 	}
 }
 
-static noinline int do_fw_call_fail(u64 arg0, u64 arg1, u64 arg2,
-				    u32 *ret_payload)
-{
-	return -ENODEV;
-}
-
-/*
- * PM function call wrapper
- * Invoke do_fw_call_smc or do_fw_call_hvc, depending on the configuration
- */
-static int (*do_fw_call)(u64, u64, u64, u32 *ret_payload) = do_fw_call_fail;
-
-/**
- * do_fw_call_smc() - Call system-level platform management layer (SMC)
- * @arg0:		Argument 0 to SMC call
- * @arg1:		Argument 1 to SMC call
- * @arg2:		Argument 2 to SMC call
- * @ret_payload:	Returned value array
- *
- * Invoke platform management function via SMC call (no hypervisor present).
- *
- * Return: Returns status, either success or error+reason
- */
-static noinline int do_fw_call_smc(u64 arg0, u64 arg1, u64 arg2,
-				   u32 *ret_payload)
-{
-	struct arm_smccc_res res;
-
-	arm_smccc_smc(arg0, arg1, arg2, 0, 0, 0, 0, 0, &res);
-
-	if (ret_payload) {
-		ret_payload[0] = lower_32_bits(res.a0);
-		ret_payload[1] = upper_32_bits(res.a0);
-		ret_payload[2] = lower_32_bits(res.a1);
-		ret_payload[3] = upper_32_bits(res.a1);
-	}
-
-	return zynqmp_pm_ret_code((enum pm_ret_status)res.a0);
-}
-
 /**
- * do_fw_call_hvc() - Call system-level platform management layer (HVC)
- * @arg0:		Argument 0 to HVC call
- * @arg1:		Argument 1 to HVC call
- * @arg2:		Argument 2 to HVC call
+ * do_fw_call() - Call system-level platform management layer
+ * @arg0:		Argument 0 to HVC/SMC call
+ * @arg1:		Argument 1 to HVC/SMC call
+ * @arg2:		Argument 2 to HVC/SMC call
  * @ret_payload:	Returned value array
  *
  * Invoke platform management function via HVC
@@ -116,12 +76,13 @@ static noinline int do_fw_call_smc(u64 arg0, u64 arg1, u64 arg2,
  *
  * Return: Returns status, either success or error+reason
  */
-static noinline int do_fw_call_hvc(u64 arg0, u64 arg1, u64 arg2,
-				   u32 *ret_payload)
+static noinline int do_fw_call(u64 arg0, u64 arg1, u64 arg2, u32 *ret_payload)
 {
 	struct arm_smccc_res res;
 
-	arm_smccc_hvc(arg0, arg1, arg2, 0, 0, 0, 0, 0, &res);
+	if (arm_smccc_1_0_invoke(arg0, arg1, arg2, 0, 0, 0, 0, 0, &res) ==
+	    SMCCC_CONDUIT_NONE)
+		return -ENODEV;
 
 	if (ret_payload) {
 		ret_payload[0] = lower_32_bits(res.a0);
@@ -287,36 +248,6 @@ static int zynqmp_pm_get_trustzone_version(u32 *version)
 	return ret;
 }
 
-/**
- * get_set_conduit_method() - Choose SMC or HVC based communication
- * @np:		Pointer to the device_node structure
- *
- * Use SMC or HVC-based functions to communicate with EL2/EL3.
- *
- * Return: Returns 0 on success or error code
- */
-static int get_set_conduit_method(struct device_node *np)
-{
-	const char *method;
-
-	if (of_property_read_string(np, "method", &method)) {
-		pr_warn("%s missing \"method\" property\n", __func__);
-		return -ENXIO;
-	}
-
-	if (!strcmp("hvc", method)) {
-		do_fw_call = do_fw_call_hvc;
-	} else if (!strcmp("smc", method)) {
-		do_fw_call = do_fw_call_smc;
-	} else {
-		pr_warn("%s Invalid \"method\" property: %s\n",
-			__func__, method);
-		return -EINVAL;
-	}
-
-	return 0;
-}
-
 /**
  * zynqmp_pm_query_data() - Get query data from firmware
  * @qdata:	Variable to the zynqmp_pm_query_data structure
@@ -790,7 +721,7 @@ static int zynqmp_firmware_probe(struct platform_device *pdev)
 	}
 	of_node_put(np);
 
-	ret = get_set_conduit_method(dev->of_node);
+	ret = devm_arm_smccc_set_conduit(dev);
 	if (ret)
 		return ret;
 
-- 
2.17.1