Re: [PATCH V2 07/12] clk: tegra: support for Tegra210 clocks suspend-resume

[Stephen Boyd <sboyd@kernel.org>]

Quoting Sowjanya Komatineni (2019-05-28 16:08:51)
> @@ -3381,6 +3398,367 @@ static struct tegra_clk_init_table init_table[] __initdata = {
>         { TEGRA210_CLK_CLK_MAX, TEGRA210_CLK_CLK_MAX, 0, 0 },
>  };
>  
> +#ifdef CONFIG_PM_SLEEP
> +static unsigned long pll_c_rate, pll_c2_rate, pll_c3_rate, pll_x_rate;
> +static unsigned long pll_c4_rate, pll_d2_rate, pll_dp_rate;
> +static unsigned long pll_re_vco_rate, pll_d_rate, pll_a_rate, pll_a1_rate;
> +static unsigned long pll_c_out1_rate;
> +static unsigned long pll_a_out0_rate, pll_c4_out3_rate;
> +static unsigned long pll_p_out_rate[5];
> +static unsigned long pll_u_out1_rate, pll_u_out2_rate;
> +static unsigned long pll_mb_rate;
> +static u32 pll_m_v;
> +static u32 pll_p_outa, pll_p_outb;
> +static u32 pll_re_out_div, pll_re_out_1;
> +static u32 cpu_softrst_ctx[3];
> +static u32 cclkg_burst_policy_ctx[2];
> +static u32 cclklp_burst_policy_ctx[2];
> +static u32 sclk_burst_policy_ctx[3];
> +static u32 sclk_ctx, spare_ctx, misc_clk_enb_ctx, clk_arm_ctx;

This is a lot of state to maintain globally. Can it go into a container
struct so we can get docs and understand what's going on a little
better?

> +
> +static struct platform_device *dfll_pdev;
> +#define car_readl(_base, _off) \
> +       readl_relaxed(clk_base + (_base) + ((_off) * 4))
> +#define car_writel(_val, _base, _off) \
> +       writel_relaxed(_val, clk_base + (_base) + ((_off) * 4))
> +
> +static u32 *periph_clk_src_ctx;
> +struct periph_source_bank {
> +       u32 start;
> +       u32 end;

Do these need to be u32 or could they be u16?

> +};
> +
> +static struct periph_source_bank periph_srcs[] = {

Can this be const?

> +       [0] = {
> +               .start = 0x100,
> +               .end = 0x198,
> +       },
> +       [1] = {
> +               .start = 0x1a0,
> +               .end = 0x1f8,
> +       },
> +       [2] = {
> +               .start = 0x3b4,
> +               .end = 0x42c,
> +       },
> +       [3] = {
> +               .start = 0x49c,
> +               .end = 0x4b4,
> +       },
> +       [4] = {
> +               .start = 0x560,
> +               .end = 0x564,
> +       },
> +       [5] = {
> +               .start = 0x600,
> +               .end = 0x678,
> +       },
> +       [6] = {
> +               .start = 0x694,
> +               .end = 0x6a0,
> +       },
> +       [7] = {
> +               .start = 0x6b8,
> +               .end = 0x718,
> +       },
> +};
> +
> +/* This array lists the valid clocks for each periph clk bank */
> +static u32 periph_clks_on[] = {

const?

> +       0xdcd7dff9,
> +       0x87d1f3e7,
> +       0xf3fed3fa,
> +       0xffc18cfb,
> +       0x793fb7ff,
> +       0x3fe66fff,
> +       0xfc1fc7ff,

What are these magic numbers?

> +};
> +
> +static inline unsigned long clk_get_rate_nolock(struct clk *clk)
> +{
> +       if (IS_ERR_OR_NULL(clk)) {

NULL is a valid clk pointer. Typically usage of IS_ERR_OR_NULL() is
wrong.

> +               WARN_ON(1);
> +               return 0;
> +       }
> +
> +       return clk_hw_get_rate(__clk_get_hw(clk));
> +}
> +
> +static inline struct clk *pll_p_clk(unsigned int x)
> +{
> +       if (x < 4) {

What is magic value 4?

> +               return clks[TEGRA210_CLK_PLL_P_OUT1 + x];
> +       } else if (x != 4) {
> +               WARN_ON(1);
> +               return NULL;
> +       } else {
> +               return clks[TEGRA210_CLK_PLL_P_OUT5];
> +       }
> +}
> +
[..]
> +
> +static void tegra210_clk_resume(void)
> +{
[..]
> +       fence_udelay(2, clk_base);
> +       for (i = 0; i < BURST_POLICY_REG_SIZE; i++) {
> +               car_writel(cclklp_burst_policy_ctx[i], CCLKLP_BURST_POLICY, i);
> +               car_writel(sclk_burst_policy_ctx[i], SCLK_BURST_POLICY, i);
> +       }
> +       car_writel(sclk_burst_policy_ctx[i], SYS_CLK_DIV, 0);
> +
> +       car_writel(sclk_ctx, SYSTEM_CLK_RATE, 0);
> +       car_writel(spare_ctx, SPARE_REG0, 0);
> +       car_writel(misc_clk_enb_ctx, MISC_CLK_ENB, 0);
> +       car_writel(clk_arm_ctx, CLK_MASK_ARM, 0);
> +
> +       /* enable all clocks before configuring clock sources */
> +       tegra_clk_periph_force_on(periph_clks_on, ARRAY_SIZE(periph_clks_on),
> +                                 clk_base);
> +
> +       wmb();

Please add a comment before barriers so we know what they're for.

> +       fence_udelay(2, clk_base);
> +