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From:   Vivek Gautam <vivek.gautam@codeaurora.org>
To:     joro@8bytes.org, andy.gross@linaro.org, will.deacon@arm.com,
        robin.murphy@arm.com, bjorn.andersson@linaro.org,
        iommu@lists.linux-foundation.org,
        linux-arm-kernel@lists.infradead.org
Cc:     david.brown@linaro.org, tfiga@chromium.org, swboyd@chromium.org,
        linux-kernel@vger.kernel.org, robdclark@gmail.com,
        Vivek Gautam <vivek.gautam@codeaurora.org>
Subject: [PATCH v2 2/4] firmware/qcom_scm: Add atomic version of io read/write APIs
Date:   Mon, 10 Sep 2018 11:55:49 +0530
Message-Id: <20180910062551.28175-3-vivek.gautam@codeaurora.org>
In-Reply-To: <20180910062551.28175-1-vivek.gautam@codeaurora.org>
References: <20180910062551.28175-1-vivek.gautam@codeaurora.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add atomic versions of qcom_scm_io_readl/writel to enable
reading/writing secure registers from atomic context.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
---
 drivers/firmware/qcom_scm-32.c | 12 ++++++++++++
 drivers/firmware/qcom_scm-64.c | 32 ++++++++++++++++++++++++++++++++
 drivers/firmware/qcom_scm.c    | 12 ++++++++++++
 drivers/firmware/qcom_scm.h    |  4 ++++
 include/linux/qcom_scm.h       |  4 ++++
 5 files changed, 64 insertions(+)

diff --git a/drivers/firmware/qcom_scm-32.c b/drivers/firmware/qcom_scm-32.c
index 4e24e591ae74..7293e5efad69 100644
--- a/drivers/firmware/qcom_scm-32.c
+++ b/drivers/firmware/qcom_scm-32.c
@@ -627,3 +627,15 @@ int __qcom_scm_io_writel(struct device *dev, phys_addr_t addr, unsigned int val)
 	return qcom_scm_call_atomic2(QCOM_SCM_SVC_IO, QCOM_SCM_IO_WRITE,
 				     addr, val);
 }
+
+int __qcom_scm_io_readl_atomic(struct device *dev, phys_addr_t addr,
+			       unsigned int *val)
+{
+	return -ENODEV;
+}
+
+int __qcom_scm_io_writel_atomic(struct device *dev, phys_addr_t addr,
+				unsigned int val)
+{
+	return -ENODEV;
+}
diff --git a/drivers/firmware/qcom_scm-64.c b/drivers/firmware/qcom_scm-64.c
index 3a8c867cdf51..6bf55403f6e3 100644
--- a/drivers/firmware/qcom_scm-64.c
+++ b/drivers/firmware/qcom_scm-64.c
@@ -558,3 +558,35 @@ int __qcom_scm_io_writel(struct device *dev, phys_addr_t addr, unsigned int val)
 	return qcom_scm_call(dev, QCOM_SCM_SVC_IO, QCOM_SCM_IO_WRITE,
 			     &desc, &res);
 }
+
+int __qcom_scm_io_readl_atomic(struct device *dev, phys_addr_t addr,
+			       unsigned int *val)
+{
+	struct qcom_scm_desc desc = {0};
+	struct arm_smccc_res res;
+	int ret;
+
+	desc.args[0] = addr;
+	desc.arginfo = QCOM_SCM_ARGS(1);
+
+	ret = qcom_scm_call_atomic(dev, QCOM_SCM_SVC_IO, QCOM_SCM_IO_READ,
+				   &desc, &res);
+	if (ret >= 0)
+		*val = res.a1;
+
+	return ret < 0 ? ret : 0;
+}
+
+int __qcom_scm_io_writel_atomic(struct device *dev, phys_addr_t addr,
+				unsigned int val)
+{
+	struct qcom_scm_desc desc = {0};
+	struct arm_smccc_res res;
+
+	desc.args[0] = addr;
+	desc.args[1] = val;
+	desc.arginfo = QCOM_SCM_ARGS(2);
+
+	return qcom_scm_call_atomic(dev, QCOM_SCM_SVC_IO, QCOM_SCM_IO_WRITE,
+				    &desc, &res);
+}
diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index e778af766fae..36da0000b37f 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -365,6 +365,18 @@ int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
 }
 EXPORT_SYMBOL(qcom_scm_io_writel);
 
+int qcom_scm_io_readl_atomic(phys_addr_t addr, unsigned int *val)
+{
+	return __qcom_scm_io_readl_atomic(__scm->dev, addr, val);
+}
+EXPORT_SYMBOL(qcom_scm_io_readl_atomic);
+
+int qcom_scm_io_writel_atomic(phys_addr_t addr, unsigned int val)
+{
+	return __qcom_scm_io_writel_atomic(__scm->dev, addr, val);
+}
+EXPORT_SYMBOL(qcom_scm_io_writel_atomic);
+
 static void qcom_scm_set_download_mode(bool enable)
 {
 	bool avail;
diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
index dcd7f7917fc7..bb176107f51e 100644
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -37,6 +37,10 @@ extern void __qcom_scm_cpu_power_down(u32 flags);
 #define QCOM_SCM_IO_WRITE		0x2
 extern int __qcom_scm_io_readl(struct device *dev, phys_addr_t addr, unsigned int *val);
 extern int __qcom_scm_io_writel(struct device *dev, phys_addr_t addr, unsigned int val);
+extern int __qcom_scm_io_readl_atomic(struct device *dev, phys_addr_t addr,
+				      unsigned int *val);
+extern int __qcom_scm_io_writel_atomic(struct device *dev, phys_addr_t addr,
+				       unsigned int val);
 
 #define QCOM_SCM_SVC_INFO		0x6
 #define QCOM_IS_CALL_AVAIL_CMD		0x1
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index 5d65521260b3..6a5d0c98b328 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -64,6 +64,8 @@ extern int qcom_scm_iommu_secure_ptbl_size(u32 spare, size_t *size);
 extern int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare);
 extern int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);
 extern int qcom_scm_io_writel(phys_addr_t addr, unsigned int val);
+extern int qcom_scm_io_readl_atomic(phys_addr_t addr, unsigned int *val);
+extern int qcom_scm_io_writel_atomic(phys_addr_t addr, unsigned int val);
 #else
 static inline
 int qcom_scm_set_cold_boot_addr(void *entry, const cpumask_t *cpus)
@@ -100,5 +102,7 @@ static inline int qcom_scm_iommu_secure_ptbl_size(u32 spare, size_t *size) { ret
 static inline int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare) { return -ENODEV; }
 static inline int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val) { return -ENODEV; }
 static inline int qcom_scm_io_writel(phys_addr_t addr, unsigned int val) { return -ENODEV; }
+static inline int qcom_scm_io_readl_atomic(phys_addr_t addr, unsigned int *val) { return -ENODEV; }
+static inline int qcom_scm_io_writel_atomic(phys_addr_t addr, unsigned int val) { return -ENODEV; }
 #endif
 #endif
-- 
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