linux-kernel - [PATCH V3 3/5] firmware: scm: Modify only the DLOAD bit in TCSR register for download mode

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Date:   Wed, 8 Feb 2023 11:03:30 +0530
From:   Poovendhan Selvaraj <quic_poovendh@...cinc.com>
To:     <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <lee@...nel.org>,
        <mturquette@...libre.com>, <sboyd@...nel.org>,
        <jassisinghbrar@...il.com>, <catalin.marinas@....com>,
        <will@...nel.org>, <shawnguo@...nel.org>, <arnd@...db.de>,
        <marcel.ziswiler@...adex.com>, <robimarko@...il.com>,
        <dmitry.baryshkov@...aro.org>, <nfraprado@...labora.com>,
        <broonie@...nel.org>, <quic_gurus@...cinc.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <quic_srichara@...cinc.com>, <quic_gokulsri@...cinc.com>,
        <quic_sjaganat@...cinc.com>, <quic_kathirav@...cinc.com>,
        <quic_arajkuma@...cinc.com>, <quic_anusha@...cinc.com>,
        <quic_devipriy@...cinc.com>
Subject: [PATCH V3 3/5] firmware: scm: Modify only the DLOAD bit in TCSR register for download mode

CrashDump collection is based on the DLOAD bit of TCSR register.
To retain other bits, we read the register and modify only the DLOAD bit as
the other bits have their own significance.

Co-developed-by: Anusha Rao <quic_anusha@...cinc.com>
Signed-off-by: Anusha Rao <quic_anusha@...cinc.com>
Co-developed-by: Kathiravan Thirumoorthy <quic_kathirav@...cinc.com>
Signed-off-by: Kathiravan Thirumoorthy <quic_kathirav@...cinc.com>
Signed-off-by: Poovendhan Selvaraj <quic_poovendh@...cinc.com>
---
 Changes in V3:
	- retain the value of tcsr register when download mode is not set

 drivers/firmware/qcom_scm.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 2000323722bf..2ad7ccf0abcd 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -407,7 +407,7 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
 }
 EXPORT_SYMBOL(qcom_scm_set_remote_state);
 
-static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
+static int __qcom_scm_set_dload_mode(struct device *dev, u32 val, bool enable)
 {
 	struct qcom_scm_desc desc = {
 		.svc = QCOM_SCM_SVC_BOOT,
@@ -417,7 +417,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
+	desc.args[1] = enable ? val | QCOM_SCM_BOOT_SET_DLOAD_MODE : val;
 
 	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
 }
@@ -426,15 +426,19 @@ static void qcom_scm_set_download_mode(bool enable)
 {
 	bool avail;
 	int ret = 0;
+	u32 dload_addr_val;
 
 	avail = __qcom_scm_is_call_available(__scm->dev,
 					     QCOM_SCM_SVC_BOOT,
 					     QCOM_SCM_BOOT_SET_DLOAD_MODE);
+	ret = qcom_scm_io_readl(__scm->dload_mode_addr, &dload_addr_val);
+
 	if (avail) {
-		ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
+		ret = __qcom_scm_set_dload_mode(__scm->dev, dload_addr_val, enable);
 	} else if (__scm->dload_mode_addr) {
 		ret = qcom_scm_io_writel(__scm->dload_mode_addr,
-				enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0);
+				enable ? dload_addr_val |
+				QCOM_SCM_BOOT_SET_DLOAD_MODE : dload_addr_val);
 	} else {
 		dev_err(__scm->dev,
 			"No available mechanism for setting download mode\n");
-- 
2.17.1