In kernel late init, it turns off all unused clocks, which
needs to access subsystem registers such as VENC and VENC_LT.

Accessing MT8173 VENC registers needs two top clocks, mm_sel and
venc_sel. Accessing VENC_LT registers needs mm_sel and venclt_sel.
So we need to keep these clocks on before accessing their registers.

This patch keeps venc_sel / venclt_sel clock on when
VENC / VENC_LT's power is on, to prevent system hang up while
accessing its registeres.

Signed-off-by: James Liao <jamesjj.l...@mediatek.com>
---

This patch is based on v4.3-rc2, to fix system hanging up issue
while disabling unused clocks.

 arch/arm64/boot/dts/mediatek/mt8173.dtsi |  6 ++-
 drivers/soc/mediatek/mtk-scpsys.c        | 67 +++++++++++++++++++++-----------
 2 files changed, 48 insertions(+), 25 deletions(-)

diff --git a/arch/arm64/boot/dts/mediatek/mt8173.dtsi 
b/arch/arm64/boot/dts/mediatek/mt8173.dtsi
index d18ee42..188917f 100644
--- a/arch/arm64/boot/dts/mediatek/mt8173.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8173.dtsi
@@ -227,8 +227,10 @@
                        #power-domain-cells = <1>;
                        reg = <0 0x10006000 0 0x1000>;
                        clocks = <&clk26m>,
-                                <&topckgen CLK_TOP_MM_SEL>;
-                       clock-names = "mfg", "mm";
+                                <&topckgen CLK_TOP_MM_SEL>,
+                                <&topckgen CLK_TOP_VENC_SEL>,
+                                <&topckgen CLK_TOP_VENC_LT_SEL>;
+                       clock-names = "mfg", "mm", "venc", "venc_lt";
                        infracfg = <&infracfg>;
                };
 
diff --git a/drivers/soc/mediatek/mtk-scpsys.c 
b/drivers/soc/mediatek/mtk-scpsys.c
index 164a7d8..06032ba 100644
--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c
@@ -54,12 +54,16 @@
 #define PWR_STATUS_USB                 BIT(25)
 
 enum clk_id {
+       MT8173_CLK_NONE,
        MT8173_CLK_MM,
        MT8173_CLK_MFG,
-       MT8173_CLK_NONE,
-       MT8173_CLK_MAX = MT8173_CLK_NONE,
+       MT8173_CLK_VENC,
+       MT8173_CLK_VENC_LT,
+       MT8173_CLK_MAX,
 };
 
+#define MAX_CLKS       2
+
 struct scp_domain_data {
        const char *name;
        u32 sta_mask;
@@ -67,7 +71,7 @@ struct scp_domain_data {
        u32 sram_pdn_bits;
        u32 sram_pdn_ack_bits;
        u32 bus_prot_mask;
-       enum clk_id clk_id;
+       enum clk_id clk_id[MAX_CLKS];
 };
 
 static const struct scp_domain_data scp_domain_data[] __initconst = {
@@ -77,7 +81,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_VDE_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(12, 12),
-               .clk_id = MT8173_CLK_MM,
+               .clk_id = {MT8173_CLK_MM},
        },
        [MT8173_POWER_DOMAIN_VENC] = {
                .name = "venc",
@@ -85,7 +89,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_VEN_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(15, 12),
-               .clk_id = MT8173_CLK_MM,
+               .clk_id = {MT8173_CLK_MM, MT8173_CLK_VENC},
        },
        [MT8173_POWER_DOMAIN_ISP] = {
                .name = "isp",
@@ -93,7 +97,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_ISP_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(13, 12),
-               .clk_id = MT8173_CLK_MM,
+               .clk_id = {MT8173_CLK_MM},
        },
        [MT8173_POWER_DOMAIN_MM] = {
                .name = "mm",
@@ -101,7 +105,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_DIS_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(12, 12),
-               .clk_id = MT8173_CLK_MM,
+               .clk_id = {MT8173_CLK_MM},
                .bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MM_M0 |
                        MT8173_TOP_AXI_PROT_EN_MM_M1,
        },
@@ -111,7 +115,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_VEN2_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(15, 12),
-               .clk_id = MT8173_CLK_MM,
+               .clk_id = {MT8173_CLK_MM, MT8173_CLK_VENC_LT},
        },
        [MT8173_POWER_DOMAIN_AUDIO] = {
                .name = "audio",
@@ -119,7 +123,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_AUDIO_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(15, 12),
-               .clk_id = MT8173_CLK_NONE,
+               .clk_id = {MT8173_CLK_NONE},
        },
        [MT8173_POWER_DOMAIN_USB] = {
                .name = "usb",
@@ -127,7 +131,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_USB_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(15, 12),
-               .clk_id = MT8173_CLK_NONE,
+               .clk_id = {MT8173_CLK_NONE},
        },
        [MT8173_POWER_DOMAIN_MFG_ASYNC] = {
                .name = "mfg_async",
@@ -135,7 +139,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_MFG_ASYNC_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = 0,
-               .clk_id = MT8173_CLK_MFG,
+               .clk_id = {MT8173_CLK_MFG},
        },
        [MT8173_POWER_DOMAIN_MFG_2D] = {
                .name = "mfg_2d",
@@ -143,7 +147,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_MFG_2D_PWR_CON,
                .sram_pdn_bits = GENMASK(11, 8),
                .sram_pdn_ack_bits = GENMASK(13, 12),
-               .clk_id = MT8173_CLK_NONE,
+               .clk_id = {MT8173_CLK_NONE},
        },
        [MT8173_POWER_DOMAIN_MFG] = {
                .name = "mfg",
@@ -151,7 +155,7 @@ static const struct scp_domain_data scp_domain_data[] 
__initconst = {
                .ctl_offs = SPM_MFG_PWR_CON,
                .sram_pdn_bits = GENMASK(13, 8),
                .sram_pdn_ack_bits = GENMASK(21, 16),
-               .clk_id = MT8173_CLK_NONE,
+               .clk_id = {MT8173_CLK_NONE},
                .bus_prot_mask = MT8173_TOP_AXI_PROT_EN_MFG_S |
                        MT8173_TOP_AXI_PROT_EN_MFG_M0 |
                        MT8173_TOP_AXI_PROT_EN_MFG_M1 |
@@ -166,7 +170,7 @@ struct scp;
 struct scp_domain {
        struct generic_pm_domain genpd;
        struct scp *scp;
-       struct clk *clk;
+       struct clk *clk[MAX_CLKS];
        u32 sta_mask;
        void __iomem *ctl_addr;
        u32 sram_pdn_bits;
@@ -212,11 +216,16 @@ static int scpsys_power_on(struct generic_pm_domain 
*genpd)
        u32 sram_pdn_ack = scpd->sram_pdn_ack_bits;
        u32 val;
        int ret;
+       int i;
+
+       for (i = 0; i < MAX_CLKS && scpd->clk[i]; i++) {
+               ret = clk_prepare_enable(scpd->clk[i]);
+               if (ret) {
+                       for (--i; i >= 0; i--)
+                               clk_disable_unprepare(scpd->clk[i]);
 
-       if (scpd->clk) {
-               ret = clk_prepare_enable(scpd->clk);
-               if (ret)
                        goto err_clk;
+               }
        }
 
        val = readl(ctl_addr);
@@ -282,7 +291,10 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
        return 0;
 
 err_pwr_ack:
-       clk_disable_unprepare(scpd->clk);
+       for (i = MAX_CLKS - 1; i >= 0; i--) {
+               if (scpd->clk[i])
+                       clk_disable_unprepare(scpd->clk[i]);
+       }
 err_clk:
        dev_err(scp->dev, "Failed to power on domain %s\n", genpd->name);
 
@@ -299,6 +311,7 @@ static int scpsys_power_off(struct generic_pm_domain *genpd)
        u32 pdn_ack = scpd->sram_pdn_ack_bits;
        u32 val;
        int ret;
+       int i;
 
        if (scpd->bus_prot_mask) {
                ret = mtk_infracfg_set_bus_protection(scp->infracfg,
@@ -360,8 +373,8 @@ static int scpsys_power_off(struct generic_pm_domain *genpd)
                        expired = true;
        }
 
-       if (scpd->clk)
-               clk_disable_unprepare(scpd->clk);
+       for (i = 0; i < MAX_CLKS && scpd->clk[i]; i++)
+               clk_disable_unprepare(scpd->clk[i]);
 
        return 0;
 
@@ -375,7 +388,7 @@ static int __init scpsys_probe(struct platform_device *pdev)
 {
        struct genpd_onecell_data *pd_data;
        struct resource *res;
-       int i, ret;
+       int i, j, ret;
        struct scp *scp;
        struct clk *clk[MT8173_CLK_MAX];
 
@@ -405,6 +418,14 @@ static int __init scpsys_probe(struct platform_device 
*pdev)
        if (IS_ERR(clk[MT8173_CLK_MFG]))
                return PTR_ERR(clk[MT8173_CLK_MFG]);
 
+       clk[MT8173_CLK_VENC] = devm_clk_get(&pdev->dev, "venc");
+       if (IS_ERR(clk[MT8173_CLK_VENC]))
+               return PTR_ERR(clk[MT8173_CLK_VENC]);
+
+       clk[MT8173_CLK_VENC_LT] = devm_clk_get(&pdev->dev, "venc_lt");
+       if (IS_ERR(clk[MT8173_CLK_VENC_LT]))
+               return PTR_ERR(clk[MT8173_CLK_VENC_LT]);
+
        scp->infracfg = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
                        "infracfg");
        if (IS_ERR(scp->infracfg)) {
@@ -428,8 +449,8 @@ static int __init scpsys_probe(struct platform_device *pdev)
                scpd->sram_pdn_bits = data->sram_pdn_bits;
                scpd->sram_pdn_ack_bits = data->sram_pdn_ack_bits;
                scpd->bus_prot_mask = data->bus_prot_mask;
-               if (data->clk_id != MT8173_CLK_NONE)
-                       scpd->clk = clk[data->clk_id];
+               for (j = 0; j < MAX_CLKS && data->clk_id[j]; j++)
+                       scpd->clk[j] = clk[data->clk_id[j]];
 
                genpd->name = data->name;
                genpd->power_off = scpsys_power_off;
-- 
1.9.1

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