linux-kernel - [PATCH 2/2] drivers: qcom: rpmh-rsc: fix read back of trigger register

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Message-Id: <20190701152907.16407-2-ilina@codeaurora.org>
Date:   Mon,  1 Jul 2019 09:29:07 -0600
From:   Lina Iyer <ilina@...eaurora.org>
To:     andy.gross@...aro.org, bjorn.andersson@...aro.org
Cc:     linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        rnayak@...eaurora.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, swboyd@...omium.org,
        dianders@...omium.org, mkshah@...eaurora.org,
        Lina Iyer <ilina@...eaurora.org>
Subject: [PATCH 2/2] drivers: qcom: rpmh-rsc: fix read back of trigger register

When triggering a TCS to send its contents, reading back the trigger
value may return an incorrect value. That is because, writing the
trigger may raise an interrupt which could be handled immediately and
the trigger value could be reset in the interrupt handler. By doing a
read back we may end up spinning waiting for the value we wrote.

Fixes: 658628 ("drivers: qcom: rpmh-rsc: add RPMH controller for QCOM
SoCs")
Signed-off-by: Lina Iyer <ilina@...eaurora.org>
---
 drivers/soc/qcom/rpmh-rsc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/rpmh-rsc.c b/drivers/soc/qcom/rpmh-rsc.c
index 92461311aef3..2fc2fa879480 100644
--- a/drivers/soc/qcom/rpmh-rsc.c
+++ b/drivers/soc/qcom/rpmh-rsc.c
@@ -300,7 +300,7 @@ static void __tcs_trigger(struct rsc_drv *drv, int tcs_id)
 	enable = TCS_AMC_MODE_ENABLE;
 	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
 	enable |= TCS_AMC_MODE_TRIGGER;
-	write_tcs_reg_sync(drv, RSC_DRV_CONTROL, tcs_id, enable);
+	write_tcs_reg(drv, RSC_DRV_CONTROL, tcs_id, enable);
 }
 
 static int check_for_req_inflight(struct rsc_drv *drv, struct tcs_group *tcs,
-- 
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