clk: meson: rework meson8b cpu clock
authorJerome Brunet <jbrunet@baylibre.com>
Mon, 12 Feb 2018 14:58:44 +0000 (15:58 +0100)
committerNeil Armstrong <narmstrong@baylibre.com>
Tue, 13 Mar 2018 09:04:03 +0000 (10:04 +0100)
Instead of migrating meson cpu_clk to clk_regmap, like the other meson
clock drivers, we take advantage of the massive rework to get rid of it
completely, and solve (the first part) of the related FIXME notice.

As pointed out in the code comments, the cpu_clk should be modeled with
dividers and muxes it is made of, instead of one big composite clock.

The cpu_clk was not working correctly to enable dvfs on meson8b. It hangs
quite often when changing the cpu clock rate. This new implementation,
based on simple elements improves the situation but the platform will
still hang from time to time. This is not acceptable so, until we can
make the mechanism around the cpu clock stable, the cpu clock subtree
has been put in read-only mode, preventing any change of the cpu clock

The notifier and read-write operation will be added back when we have a
solution to the problem.

Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
drivers/clk/meson/meson8b.c
drivers/clk/meson/meson8b.h

index 625d953511bea4a171cb60e66dae1d4a6ccc0e0f..ea73b5de967257b4138849eeeed9f01706aeb2c9 100644 (file)
@@ -99,20 +99,6 @@ static const struct pll_rate_table sys_pll_rate_table[] = {
        { /* sentinel */ },
 };
 
-static const struct clk_div_table cpu_div_table[] = {
-       { .val = 1, .div = 1 },
-       { .val = 2, .div = 2 },
-       { .val = 3, .div = 3 },
-       { .val = 2, .div = 4 },
-       { .val = 3, .div = 6 },
-       { .val = 4, .div = 8 },
-       { .val = 5, .div = 10 },
-       { .val = 6, .div = 12 },
-       { .val = 7, .div = 14 },
-       { .val = 8, .div = 16 },
-       { /* sentinel */ },
-};
-
 static struct clk_fixed_rate meson8b_xtal = {
        .fixed_rate = 24000000,
        .hw.init = &(struct clk_init_data){
@@ -227,7 +213,7 @@ static struct clk_regmap meson8b_sys_pll = {
        },
        .hw.init = &(struct clk_init_data){
                .name = "sys_pll",
-               .ops = &meson_clk_pll_ops,
+               .ops = &meson_clk_pll_ro_ops,
                .parent_names = (const char *[]){ "xtal" },
                .num_parents = 1,
                .flags = CLK_GET_RATE_NOCACHE,
@@ -417,23 +403,6 @@ static struct clk_regmap meson8b_mpll2 = {
        },
 };
 
-/*
- * FIXME cpu clocks and the legacy composite clocks (e.g. clk81) are both PLL
- * post-dividers and should be modeled with their respective PLLs via the
- * forthcoming coordinated clock rates feature
- */
-static struct meson_clk_cpu meson8b_cpu_clk = {
-       .reg_off = HHI_SYS_CPU_CLK_CNTL1,
-       .div_table = cpu_div_table,
-       .clk_nb.notifier_call = meson_clk_cpu_notifier_cb,
-       .hw.init = &(struct clk_init_data){
-               .name = "cpu_clk",
-               .ops = &meson_clk_cpu_ops,
-               .parent_names = (const char *[]){ "sys_pll" },
-               .num_parents = 1,
-       },
-};
-
 static u32 mux_table_clk81[]   = { 6, 5, 7 };
 static struct clk_regmap meson8b_mpeg_clk_sel = {
        .data = &(struct clk_regmap_mux_data){
@@ -486,6 +455,108 @@ struct clk_regmap meson8b_clk81 = {
        },
 };
 
+struct clk_regmap meson8b_cpu_in_sel = {
+       .data = &(struct clk_regmap_mux_data){
+               .offset = HHI_SYS_CPU_CLK_CNTL0,
+               .mask = 0x1,
+               .shift = 0,
+       },
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_in_sel",
+               .ops = &clk_regmap_mux_ro_ops,
+               .parent_names = (const char *[]){ "xtal", "sys_pll" },
+               .num_parents = 2,
+               .flags = (CLK_SET_RATE_PARENT |
+                         CLK_SET_RATE_NO_REPARENT),
+       },
+};
+
+static struct clk_fixed_factor meson8b_cpu_div2 = {
+       .mult = 1,
+       .div = 2,
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_div2",
+               .ops = &clk_fixed_factor_ops,
+               .parent_names = (const char *[]){ "cpu_in_sel" },
+               .num_parents = 1,
+               .flags = CLK_SET_RATE_PARENT,
+       },
+};
+
+static struct clk_fixed_factor meson8b_cpu_div3 = {
+       .mult = 1,
+       .div = 3,
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_div3",
+               .ops = &clk_fixed_factor_ops,
+               .parent_names = (const char *[]){ "cpu_in_sel" },
+               .num_parents = 1,
+               .flags = CLK_SET_RATE_PARENT,
+       },
+};
+
+static const struct clk_div_table cpu_scale_table[] = {
+       { .val = 2, .div = 4 },
+       { .val = 3, .div = 6 },
+       { .val = 4, .div = 8 },
+       { .val = 5, .div = 10 },
+       { .val = 6, .div = 12 },
+       { .val = 7, .div = 14 },
+       { .val = 8, .div = 16 },
+       { /* sentinel */ },
+};
+
+struct clk_regmap meson8b_cpu_scale_div = {
+       .data = &(struct clk_regmap_div_data){
+               .offset =  HHI_SYS_CPU_CLK_CNTL1,
+               .shift = 20,
+               .width = 9,
+               .table = cpu_scale_table,
+               .flags = CLK_DIVIDER_ALLOW_ZERO,
+       },
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_scale_div",
+               .ops = &clk_regmap_divider_ro_ops,
+               .parent_names = (const char *[]){ "cpu_in_sel" },
+               .num_parents = 1,
+               .flags = CLK_SET_RATE_PARENT,
+       },
+};
+
+struct clk_regmap meson8b_cpu_scale_out_sel = {
+       .data = &(struct clk_regmap_mux_data){
+               .offset = HHI_SYS_CPU_CLK_CNTL0,
+               .mask = 0x3,
+               .shift = 2,
+       },
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_scale_out_sel",
+               .ops = &clk_regmap_mux_ro_ops,
+               .parent_names = (const char *[]) { "cpu_in_sel",
+                                                  "cpu_div2",
+                                                  "cpu_div3",
+                                                  "cpu_scale_div" },
+               .num_parents = 4,
+               .flags = CLK_SET_RATE_PARENT,
+       },
+};
+
+struct clk_regmap meson8b_cpu_clk = {
+       .data = &(struct clk_regmap_mux_data){
+               .offset = HHI_SYS_CPU_CLK_CNTL0,
+               .mask = 0x1,
+               .shift = 7,
+       },
+       .hw.init = &(struct clk_init_data){
+               .name = "cpu_clk",
+               .ops = &clk_regmap_mux_ro_ops,
+               .parent_names = (const char *[]){ "xtal", "cpu_out_sel" },
+               .num_parents = 2,
+               .flags = (CLK_SET_RATE_PARENT |
+                         CLK_SET_RATE_NO_REPARENT),
+       },
+};
+
 /* Everything Else (EE) domain gates */
 
 static MESON_GATE(meson8b_ddr, HHI_GCLK_MPEG0, 0);
@@ -670,6 +741,11 @@ static struct clk_hw_onecell_data meson8b_hw_onecell_data = {
                [CLKID_MPLL0_DIV]           = &meson8b_mpll0_div.hw,
                [CLKID_MPLL1_DIV]           = &meson8b_mpll1_div.hw,
                [CLKID_MPLL2_DIV]           = &meson8b_mpll2_div.hw,
+               [CLKID_CPU_IN_SEL]          = &meson8b_cpu_in_sel.hw,
+               [CLKID_CPU_DIV2]            = &meson8b_cpu_div2.hw,
+               [CLKID_CPU_DIV3]            = &meson8b_cpu_div3.hw,
+               [CLKID_CPU_SCALE_DIV]       = &meson8b_cpu_scale_div.hw,
+               [CLKID_CPU_SCALE_OUT_SEL]   = &meson8b_cpu_scale_out_sel.hw,
                [CLK_NR_CLKS]               = NULL,
        },
        .num = CLK_NR_CLKS,
@@ -765,6 +841,10 @@ static struct clk_regmap *const meson8b_clk_regmaps[] = {
        &meson8b_fixed_pll,
        &meson8b_vid_pll,
        &meson8b_sys_pll,
+       &meson8b_cpu_in_sel,
+       &meson8b_cpu_scale_div,
+       &meson8b_cpu_scale_out_sel,
+       &meson8b_cpu_clk,
 };
 
 static const struct meson8b_clk_reset_line {
@@ -875,8 +955,7 @@ static const struct regmap_config clkc_regmap_config = {
 static int meson8b_clkc_probe(struct platform_device *pdev)
 {
        int ret, i;
-       struct clk_hw *parent_hw;
-       struct clk *parent_clk;
+       struct clk *clk;
        struct device *dev = &pdev->dev;
        struct regmap *map;
 
@@ -887,9 +966,6 @@ static int meson8b_clkc_probe(struct platform_device *pdev)
        if (IS_ERR(map))
                return PTR_ERR(map);
 
-       /* Populate the base address for CPU clk */
-       meson8b_cpu_clk.base = clk_base;
-
        /* Populate regmap for the regmap backed clocks */
        for (i = 0; i < ARRAY_SIZE(meson8b_clk_regmaps); i++)
                meson8b_clk_regmaps[i]->map = map;
@@ -908,29 +984,6 @@ static int meson8b_clkc_probe(struct platform_device *pdev)
                        return ret;
        }
 
-       /*
-        * Register CPU clk notifier
-        *
-        * FIXME this is wrong for a lot of reasons. First, the muxes should be
-        * struct clk_hw objects. Second, we shouldn't program the muxes in
-        * notifier handlers. The tricky programming sequence will be handled
-        * by the forthcoming coordinated clock rates mechanism once that
-        * feature is released.
-        *
-        * Furthermore, looking up the parent this way is terrible. At some
-        * point we will stop allocating a default struct clk when registering
-        * a new clk_hw, and this hack will no longer work. Releasing the ccr
-        * feature before that time solves the problem :-)
-        */
-       parent_hw = clk_hw_get_parent(&meson8b_cpu_clk.hw);
-       parent_clk = parent_hw->clk;
-       ret = clk_notifier_register(parent_clk, &meson8b_cpu_clk.clk_nb);
-       if (ret) {
-               pr_err("%s: failed to register clock notifier for cpu_clk\n",
-                               __func__);
-               return ret;
-       }
-
        return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
                                           &meson8b_hw_onecell_data);
 }
index f2780508edec48769d43a26ceb6894456d6d815b..73dae83d9932e26f9a648a29004383c21bc3e120 100644 (file)
 #define CLKID_MPLL0_DIV                96
 #define CLKID_MPLL1_DIV                97
 #define CLKID_MPLL2_DIV                98
+#define CLKID_CPU_IN_SEL       99
+#define CLKID_CPU_DIV2         100
+#define CLKID_CPU_DIV3         101
+#define CLKID_CPU_SCALE_DIV    102
+#define CLKID_CPU_SCALE_OUT_SEL        103
 
-#define CLK_NR_CLKS            99
+#define CLK_NR_CLKS            104
 
 /*
  * include the CLKID and RESETID that have