linux-kernel - [PATCH v2 7/9] clk: qcom: gdsc: Implement NO_RET

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Message-Id: <20210113183817.447866-8-angelogioacchino.delregno@somainline.org>
Date:   Wed, 13 Jan 2021 19:38:15 +0100
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>
To:     agross@...nel.org
Cc:     bjorn.andersson@...aro.org, mturquette@...libre.com,
        robh+dt@...nel.org, linux-arm-msm@...r.kernel.org,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, phone-devel@...r.kernel.org,
        konrad.dybcio@...ainline.org, marijn.suijten@...ainline.org,
        martin.botka@...ainline.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>
Subject: [PATCH v2 7/9] clk: qcom: gdsc: Implement NO_RET_PERIPH flag

In some rare occasions, we want to only set the RETAIN_MEM bit, but
not the RETAIN_PERIPH one: this is seen on at least SDM630/636/660's
GPU-GX GDSC, where unsetting and setting back the RETAIN_PERIPH bit
will generate chaos and panics during GPU suspend time (mainly, the
chaos is unaligned access).

For this reason, introduce a new NO_RET_PERIPH flag to the GDSC
driver to address this corner case.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
---
 drivers/clk/qcom/gdsc.c | 10 ++++++++--
 drivers/clk/qcom/gdsc.h |  3 ++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index af26e0695b86..51ed640e527b 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -183,7 +183,10 @@ static inline int gdsc_assert_reset(struct gdsc *sc)
 static inline void gdsc_force_mem_on(struct gdsc *sc)
 {
 	int i;
-	u32 mask = RETAIN_MEM | RETAIN_PERIPH;
+	u32 mask = RETAIN_MEM;
+
+	if (!(sc->flags & NO_RET_PERIPH))
+		mask |= RETAIN_PERIPH;
 
 	for (i = 0; i < sc->cxc_count; i++)
 		regmap_update_bits(sc->regmap, sc->cxcs[i], mask, mask);
@@ -192,7 +195,10 @@ static inline void gdsc_force_mem_on(struct gdsc *sc)
 static inline void gdsc_clear_mem_on(struct gdsc *sc)
 {
 	int i;
-	u32 mask = RETAIN_MEM | RETAIN_PERIPH;
+	u32 mask = RETAIN_MEM;
+
+	if (!(sc->flags & NO_RET_PERIPH))
+		mask |= RETAIN_PERIPH;
 
 	for (i = 0; i < sc->cxc_count; i++)
 		regmap_update_bits(sc->regmap, sc->cxcs[i], mask, 0);
diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index bd537438c793..5bb396b344d1 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -42,7 +42,7 @@ struct gdsc {
 #define PWRSTS_ON		BIT(2)
 #define PWRSTS_OFF_ON		(PWRSTS_OFF | PWRSTS_ON)
 #define PWRSTS_RET_ON		(PWRSTS_RET | PWRSTS_ON)
-	const u8			flags;
+	const u16			flags;
 #define VOTABLE		BIT(0)
 #define CLAMP_IO	BIT(1)
 #define HW_CTRL		BIT(2)
@@ -51,6 +51,7 @@ struct gdsc {
 #define POLL_CFG_GDSCR	BIT(5)
 #define ALWAYS_ON	BIT(6)
 #define RETAIN_FF_ENABLE	BIT(7)
+#define NO_RET_PERIPH	BIT(8)
 	struct reset_controller_dev	*rcdev;
 	unsigned int			*resets;
 	unsigned int			reset_count;
-- 
2.29.2