[PATCH v2 2/5] firmware: qcom: scm: Optionally remove SCM call serialization

[Guru Das Srinagesh]

Some firmware versions support the handling of multiple SCM calls at the
same time. Add a device tree boolean property which, when specified,
allows this to happen.

Signed-off-by: Guru Das Srinagesh <quic_gurus@xxxxxxxxxxx>
---
 drivers/firmware/qcom_scm-smc.c | 8 ++++++--
 drivers/firmware/qcom_scm.c     | 6 ++++++
 drivers/firmware/qcom_scm.h     | 2 ++
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/qcom_scm-smc.c b/drivers/firmware/qcom_scm-smc.c
index d111833..66193c2 100644
--- a/drivers/firmware/qcom_scm-smc.c
+++ b/drivers/firmware/qcom_scm-smc.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2015,2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #include <linux/io.h>
@@ -63,11 +64,14 @@ static void __scm_smc_do(const struct arm_smccc_args *smc,
 	}
 
 	do {
-		mutex_lock(&qcom_scm_lock);
+		if (!qcom_scm_allow_multicall)
+			mutex_lock(&qcom_scm_lock);
 
 		__scm_smc_do_quirk(smc, res);
 
-		mutex_unlock(&qcom_scm_lock);
+		if (!qcom_scm_allow_multicall)
+			mutex_unlock(&qcom_scm_lock);
+
 
 		if (res->a0 == QCOM_SCM_V2_EBUSY) {
 			if (retry_count++ > QCOM_SCM_EBUSY_MAX_RETRY)
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 3163660..4046073 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2010,2015,2019 The Linux Foundation. All rights reserved.
  * Copyright (C) 2015 Linaro Ltd.
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #include <linux/platform_device.h>
 #include <linux/init.h>
@@ -22,6 +23,8 @@
 static bool download_mode = IS_ENABLED(CONFIG_QCOM_SCM_DOWNLOAD_MODE_DEFAULT);
 module_param(download_mode, bool, 0);
 
+bool qcom_scm_allow_multicall = false;
+
 #define SCM_HAS_CORE_CLK	BIT(0)
 #define SCM_HAS_IFACE_CLK	BIT(1)
 #define SCM_HAS_BUS_CLK		BIT(2)
@@ -1333,6 +1336,9 @@ static int qcom_scm_probe(struct platform_device *pdev)
 	__scm = scm;
 	__scm->dev = &pdev->dev;
 
+	qcom_scm_allow_multicall = of_property_read_bool(__scm->dev->of_node,
+							"allow-multi-call");
+
 	__get_convention();
 
 	/*
diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
index 0d51eef..c0a4d6b 100644
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /* Copyright (c) 2010-2015,2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #ifndef __QCOM_SCM_INT_H
 #define __QCOM_SCM_INT_H
@@ -12,6 +13,7 @@ enum qcom_scm_convention {
 };
 
 extern enum qcom_scm_convention qcom_scm_convention;
+extern bool qcom_scm_allow_multicall;
 
 #define MAX_QCOM_SCM_ARGS 10
 #define MAX_QCOM_SCM_RETS 3
-- 
2.7.4