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From:   Kathiravan T <quic_kathirav@quicinc.com>
To:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Linus Walleij <linus.walleij@linaro.org>,
        Elliot Berman <quic_eberman@quicinc.com>,
        "Mukesh Ojha" <quic_mojha@quicinc.com>,
        Kalle Valo <kvalo@kernel.org>,
        Loic Poulain <loic.poulain@linaro.org>,
        <linux-arm-msm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-gpio@vger.kernel.org>
CC:     <quic_srichara@quicinc.com>, <quic_sjaganat@quicinc.com>,
        <quic_anusha@quicinc.com>, <quic_saahtoma@quicinc.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Kathiravan T <quic_kathirav@quicinc.com>
Subject: [PATCH V5 1/3] firmware: qcom_scm: provide a read-modify-write function
Date:   Thu, 20 Jul 2023 12:34:06 +0530
Message-ID: <20230720070408.1093698-2-quic_kathirav@quicinc.com>
In-Reply-To: <20230720070408.1093698-1-quic_kathirav@quicinc.com>
References: <20230720070408.1093698-1-quic_kathirav@quicinc.com>
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From: Mukesh Ojha <quic_mojha@quicinc.com>

It was realized by Srinivas K. that there is a need of read-modify-write
scm exported function so that it can be used by multiple clients.

Let's introduce qcom_scm_io_update_field() which masks out the bits and
write the passed value to that bit-offset.

Suggested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
---
Changes in V5:
	- No changes

 drivers/firmware/qcom_scm.c            | 15 +++++++++++++++
 include/linux/firmware/qcom/qcom_scm.h |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index fde33acd46b7..104d86e49b97 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -407,6 +407,21 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
 }
 EXPORT_SYMBOL(qcom_scm_set_remote_state);
 
+int qcom_scm_io_update_field(phys_addr_t addr, unsigned int mask, unsigned int val)
+{
+	unsigned int old, new;
+	int ret;
+
+	ret = qcom_scm_io_readl(addr, &old);
+	if (ret)
+		return ret;
+
+	new = (old & ~mask) | (val & mask);
+
+	return qcom_scm_io_writel(addr, new);
+}
+EXPORT_SYMBOL(qcom_scm_io_update_field);
+
 static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 {
 	struct qcom_scm_desc desc = {
diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
index 250ea4efb7cb..ca41e4eb33ad 100644
--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h
@@ -84,6 +84,8 @@ extern bool qcom_scm_pas_supported(u32 peripheral);
 
 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_update_field(phys_addr_t addr, unsigned int mask,
+				    unsigned int val);
 
 extern bool qcom_scm_restore_sec_cfg_available(void);
 extern int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare);
-- 
2.34.1