linux-kernel - [PATCH v3 2/2] firmware: arm_scmi: Augment SMC/HVC to allow optional parameter

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Message-ID: <20230417174401.19563-3-quic_nkela@quicinc.com>
Date:   Mon, 17 Apr 2023 10:44:01 -0700
From:   Nikunj Kela <quic_nkela@...cinc.com>
To:     <sudeep.holla@....com>
CC:     <cristian.marussi@....com>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Nikunj Kela <quic_nkela@...cinc.com>
Subject: [PATCH v3 2/2] firmware: arm_scmi: Augment SMC/HVC to allow optional parameter

This patch add support for passing shmem channel address as parameter
in smc/hvc call. This patch is useful when multiple scmi instances are
using same smc-id and firmware needs to distiguish among the instances.

Signed-off-by: Nikunj Kela <quic_nkela@...cinc.com>
---
 drivers/firmware/arm_scmi/driver.c |  1 +
 drivers/firmware/arm_scmi/smc.c    | 25 ++++++++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index e7d97b59963b..b5957cc12fee 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -2914,6 +2914,7 @@ static const struct of_device_id scmi_of_match[] = {
 #endif
 #ifdef CONFIG_ARM_SCMI_TRANSPORT_SMC
 	{ .compatible = "arm,scmi-smc", .data = &scmi_smc_desc},
+	{ .compatible = "arm,scmi-smc-param", .data = &scmi_smc_desc},
 #endif
 #ifdef CONFIG_ARM_SCMI_TRANSPORT_VIRTIO
 	{ .compatible = "arm,scmi-virtio", .data = &scmi_virtio_desc},
diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
index 93272e4bbd12..e28387346d33 100644
--- a/drivers/firmware/arm_scmi/smc.c
+++ b/drivers/firmware/arm_scmi/smc.c
@@ -20,6 +20,9 @@
 
 #include "common.h"
 
+#define lower32(x)	((u32)((x) & 0xffffffff))
+#define upper32(x)	((u32)(((u64)(x) >> 32) & 0xffffffff))
+
 /**
  * struct scmi_smc - Structure representing a SCMI smc transport
  *
@@ -30,6 +33,8 @@
  * @inflight: Atomic flag to protect access to Tx/Rx shared memory area.
  *	      Used when operating in atomic mode.
  * @func_id: smc/hvc call function id
+ * @is_smc64: smc/hvc calling convention type 64 vs 32
+ * @param: physical address of the shmem channel
  */
 
 struct scmi_smc {
@@ -40,6 +45,8 @@ struct scmi_smc {
 #define INFLIGHT_NONE	MSG_TOKEN_MAX
 	atomic_t inflight;
 	u32 func_id;
+	bool is_smc64;
+	phys_addr_t param;
 };
 
 static irqreturn_t smc_msg_done_isr(int irq, void *data)
@@ -137,6 +144,8 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	if (ret < 0)
 		return ret;
 
+	if (of_device_is_compatible(dev->of_node, "arm,scmi-smc-param"))
+		scmi_info->param = res.start;
 	/*
 	 * If there is an interrupt named "a2p", then the service and
 	 * completion of a message is signaled by an interrupt rather than by
@@ -156,6 +165,7 @@ static int smc_chan_setup(struct scmi_chan_info *cinfo, struct device *dev,
 	}
 
 	scmi_info->func_id = func_id;
+	scmi_info->is_smc64 = ARM_SMCCC_IS_64(func_id);
 	scmi_info->cinfo = cinfo;
 	smc_channel_lock_init(scmi_info);
 	cinfo->transport_info = scmi_info;
@@ -188,7 +198,20 @@ static int smc_send_message(struct scmi_chan_info *cinfo,
 
 	shmem_tx_prepare(scmi_info->shmem, xfer, cinfo);
 
-	arm_smccc_1_1_invoke(scmi_info->func_id, 0, 0, 0, 0, 0, 0, 0, &res);
+#ifdef CONFIG_ARM64
+	/*
+	 * if SMC32 convention is used, pass 64 bit address in
+	 * two parameters
+	 */
+	if (!scmi_info->is_smc64)
+		arm_smccc_1_1_invoke(scmi_info->func_id,
+				     lower32(scmi_info->param),
+				     upper32(scmi_info->param),
+				     0, 0, 0, 0, 0, &res);
+	else
+#endif
+		arm_smccc_1_1_invoke(scmi_info->func_id, scmi_info->param,
+				     0, 0, 0, 0, 0, 0, &res);
 
 	/* Only SMCCC_RET_NOT_SUPPORTED is valid error code */
 	if (res.a0) {
-- 
2.17.1