linux-kernel - [PATCH] firmware: qcom_scm: Fix legacy convention SCM accessors

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Date:   Sat, 4 Jul 2020 18:23:34 +0100
From:   Jonathan McDowell <noodles@...th.li>
To:     Elliot Berman <eberman@...eaurora.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] firmware: qcom_scm: Fix legacy convention SCM accessors

The move to a combined driver for the QCOM SCM hardware changed the
io_writel and io_readl helpers to use non-atomic calls, despite the
commit message saying that atomic was a better option. This breaks these
helpers on hardware that uses the old legacy convention (access fails
with a -95 return code). Switch back to using the atomic calls.

Observed as a failure routing GPIO interrupts to the Apps processor on
an IPQ8064; fix is confirmed as correctly allowing the interrupts to be
routed and observed.

Fixes: 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers")
Cc: stable@...r.kernel.org
Signed-off-by: Jonathan McDowell <noodles@...th.li>
---
 drivers/firmware/qcom_scm.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 0e7233a20f34..d4fda210adfe 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -391,7 +391,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 
 	desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
 }
 
 static void qcom_scm_set_download_mode(bool enable)
@@ -650,7 +650,7 @@ int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val)
 	int ret;
 
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call_atomic(__scm->dev, &desc, &res);
 	if (ret >= 0)
 		*val = res.result[0];
 
@@ -669,8 +669,7 @@ int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_io_writel);
 
-- 
2.20.1