linux-kernel - [PATCH] clk: mediatek: mt8195-infra_ao: Set pwrmcu clocks as critical

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Message-Id: <20220719093316.37253-1-angelogioacchino.delregno@collabora.com>
Date:   Tue, 19 Jul 2022 11:33:16 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     mturquette@...libre.com
Cc:     sboyd@...nel.org, matthias.bgg@...il.com,
        angelogioacchino.delregno@...labora.com, wenst@...omium.org,
        chun-jie.chen@...iatek.com, miles.chen@...iatek.com,
        rex-bc.chen@...iatek.com, linux-clk@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH] clk: mediatek: mt8195-infra_ao: Set pwrmcu clocks as critical

The pwrmcu is responsible for power management and idle states in SSPM:
on older SoCs this was managed in Linux drivers like sspm/mcupm/eemgpu
but, at least on MT8195, this functionality was transferred to the ATF
firmware.
For this reason, turning off the pwrmcu related clocks from the kernel
will lead to unability to resume the platform after suspend and other
currently unknown PM related side-effects.

Set the PWRMCU and PWRMCU_BUS_H clocks as critical to prevent the
kernel from turning them off, fixing the aforementioned issue.

Fixes: e2edf59dec0b ("clk: mediatek: Add MT8195 infrastructure clock support")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/clk/mediatek/clk-mt8195-infra_ao.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/mediatek/clk-mt8195-infra_ao.c b/drivers/clk/mediatek/clk-mt8195-infra_ao.c
index ce7ac16a2f42..75b54ec9c46c 100644
--- a/drivers/clk/mediatek/clk-mt8195-infra_ao.c
+++ b/drivers/clk/mediatek/clk-mt8195-infra_ao.c
@@ -55,8 +55,12 @@ static const struct mtk_gate_regs infra_ao4_cg_regs = {
 #define GATE_INFRA_AO1(_id, _name, _parent, _shift)	\
 	GATE_INFRA_AO1_FLAGS(_id, _name, _parent, _shift, 0)
 
+#define GATE_INFRA_AO2_FLAGS(_id, _name, _parent, _shift, _flag)	\
+	GATE_MTK_FLAGS(_id, _name, _parent, &infra_ao2_cg_regs, _shift,	\
+		       &mtk_clk_gate_ops_setclr, _flag)
+
 #define GATE_INFRA_AO2(_id, _name, _parent, _shift)			\
-	GATE_MTK(_id, _name, _parent, &infra_ao2_cg_regs, _shift, &mtk_clk_gate_ops_setclr)
+	GATE_INFRA_AO2_FLAGS(_id, _name, _parent, _shift, 0)
 
 #define GATE_INFRA_AO3_FLAGS(_id, _name, _parent, _shift, _flag)		\
 	GATE_MTK_FLAGS(_id, _name, _parent, &infra_ao3_cg_regs, _shift,	\
@@ -136,8 +140,11 @@ static const struct mtk_gate infra_ao_clks[] = {
 	GATE_INFRA_AO2(CLK_INFRA_AO_UNIPRO_SYS, "infra_ao_unipro_sys", "top_ufs", 11),
 	GATE_INFRA_AO2(CLK_INFRA_AO_UNIPRO_TICK, "infra_ao_unipro_tick", "top_ufs_tick1us", 12),
 	GATE_INFRA_AO2(CLK_INFRA_AO_UFS_MP_SAP_B, "infra_ao_ufs_mp_sap_b", "top_ufs_mp_sap_cfg", 13),
-	GATE_INFRA_AO2(CLK_INFRA_AO_PWRMCU, "infra_ao_pwrmcu", "top_pwrmcu", 15),
-	GATE_INFRA_AO2(CLK_INFRA_AO_PWRMCU_BUS_H, "infra_ao_pwrmcu_bus_h", "top_axi", 17),
+	/* pwrmcu is used by ATF for platform PM: clocks must never be disabled by the kernel */
+	GATE_INFRA_AO2_FLAGS(CLK_INFRA_AO_PWRMCU, "infra_ao_pwrmcu", "top_pwrmcu", 15,
+			     CLK_IS_CRITICAL),
+	GATE_INFRA_AO2_FLAGS(CLK_INFRA_AO_PWRMCU_BUS_H, "infra_ao_pwrmcu_bus_h", "top_axi", 17,
+			     CLK_IS_CRITICAL),
 	GATE_INFRA_AO2(CLK_INFRA_AO_APDMA_B, "infra_ao_apdma_b", "top_axi", 18),
 	GATE_INFRA_AO2(CLK_INFRA_AO_SPI4, "infra_ao_spi4", "top_spi", 25),
 	GATE_INFRA_AO2(CLK_INFRA_AO_SPI5, "infra_ao_spi5", "top_spi", 26),
-- 
2.35.1