From 53f69967dca340d79c8dda0734b8912241cb4d31 Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Tue, 24 May 2016 15:19:16 +0200 Subject: [PATCH] clk: samsung: cpu: prepare for adding Exynos5433 CPU clocks Exynos5433 uses different register layout for CPU clock registers than earlier SoCs so add new code for handling this layout. Also add new CLK_CPU_HAS_E5433_REGS_LAYOUT flag to request using it. There should be no functional change resulting from this patch. Cc: Kukjin Kim CC: Krzysztof Kozlowski Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Sylwester Nawrocki --- drivers/clk/samsung/clk-cpu.c | 131 +++++++++++++++++++++++++++++++++- drivers/clk/samsung/clk-cpu.h | 4 +- 2 files changed, 133 insertions(+), 2 deletions(-) diff --git a/drivers/clk/samsung/clk-cpu.c b/drivers/clk/samsung/clk-cpu.c index 813003d6ce09..8bf7e805fd34 100644 --- a/drivers/clk/samsung/clk-cpu.c +++ b/drivers/clk/samsung/clk-cpu.c @@ -45,6 +45,13 @@ #define E4210_DIV_STAT_CPU0 0x400 #define E4210_DIV_STAT_CPU1 0x404 +#define E5433_MUX_SEL2 0x008 +#define E5433_MUX_STAT2 0x208 +#define E5433_DIV_CPU0 0x400 +#define E5433_DIV_CPU1 0x404 +#define E5433_DIV_STAT_CPU0 0x500 +#define E5433_DIV_STAT_CPU1 0x504 + #define E4210_DIV0_RATIO0_MASK 0x7 #define E4210_DIV1_HPM_MASK (0x7 << 4) #define E4210_DIV1_COPY_MASK (0x7 << 0) @@ -252,6 +259,102 @@ static int exynos_cpuclk_post_rate_change(struct clk_notifier_data *ndata, return 0; } +/* + * Helper function to set the 'safe' dividers for the CPU clock. The parameters + * div and mask contain the divider value and the register bit mask of the + * dividers to be programmed. + */ +static void exynos5433_set_safe_div(void __iomem *base, unsigned long div, + unsigned long mask) +{ + unsigned long div0; + + div0 = readl(base + E5433_DIV_CPU0); + div0 = (div0 & ~mask) | (div & mask); + writel(div0, base + E5433_DIV_CPU0); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU0, mask); +} + +/* handler for pre-rate change notification from parent clock */ +static int exynos5433_cpuclk_pre_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + const struct exynos_cpuclk_cfg_data *cfg_data = cpuclk->cfg; + unsigned long alt_prate = clk_get_rate(cpuclk->alt_parent); + unsigned long alt_div = 0, alt_div_mask = DIV_MASK; + unsigned long div0, div1 = 0, mux_reg; + unsigned long flags; + + /* find out the divider values to use for clock data */ + while ((cfg_data->prate * 1000) != ndata->new_rate) { + if (cfg_data->prate == 0) + return -EINVAL; + cfg_data++; + } + + spin_lock_irqsave(cpuclk->lock, flags); + + /* + * For the selected PLL clock frequency, get the pre-defined divider + * values. + */ + div0 = cfg_data->div0; + div1 = cfg_data->div1; + + /* + * If the old parent clock speed is less than the clock speed of + * the alternate parent, then it should be ensured that at no point + * the armclk speed is more than the old_prate until the dividers are + * set. Also workaround the issue of the dividers being set to lower + * values before the parent clock speed is set to new lower speed + * (this can result in too high speed of armclk output clocks). + */ + if (alt_prate > ndata->old_rate || ndata->old_rate > ndata->new_rate) { + unsigned long tmp_rate = min(ndata->old_rate, ndata->new_rate); + + alt_div = DIV_ROUND_UP(alt_prate, tmp_rate) - 1; + WARN_ON(alt_div >= MAX_DIV); + + exynos5433_set_safe_div(base, alt_div, alt_div_mask); + div0 |= alt_div; + } + + /* select the alternate parent */ + mux_reg = readl(base + E5433_MUX_SEL2); + writel(mux_reg | 1, base + E5433_MUX_SEL2); + wait_until_mux_stable(base + E5433_MUX_STAT2, 0, 2); + + /* alternate parent is active now. set the dividers */ + writel(div0, base + E5433_DIV_CPU0); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU0, DIV_MASK_ALL); + + writel(div1, base + E5433_DIV_CPU1); + wait_until_divider_stable(base + E5433_DIV_STAT_CPU1, DIV_MASK_ALL); + + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + +/* handler for post-rate change notification from parent clock */ +static int exynos5433_cpuclk_post_rate_change(struct clk_notifier_data *ndata, + struct exynos_cpuclk *cpuclk, void __iomem *base) +{ + unsigned long div = 0, div_mask = DIV_MASK; + unsigned long mux_reg; + unsigned long flags; + + spin_lock_irqsave(cpuclk->lock, flags); + + /* select apll as the alternate parent */ + mux_reg = readl(base + E5433_MUX_SEL2); + writel(mux_reg & ~1, base + E5433_MUX_SEL2); + wait_until_mux_stable(base + E5433_MUX_STAT2, 0, 1); + + exynos5433_set_safe_div(base, div, div_mask); + spin_unlock_irqrestore(cpuclk->lock, flags); + return 0; +} + /* * This notifier function is called for the pre-rate and post-rate change * notifications of the parent clock of cpuclk. @@ -275,6 +378,29 @@ static int exynos_cpuclk_notifier_cb(struct notifier_block *nb, return notifier_from_errno(err); } +/* + * This notifier function is called for the pre-rate and post-rate change + * notifications of the parent clock of cpuclk. + */ +static int exynos5433_cpuclk_notifier_cb(struct notifier_block *nb, + unsigned long event, void *data) +{ + struct clk_notifier_data *ndata = data; + struct exynos_cpuclk *cpuclk; + void __iomem *base; + int err = 0; + + cpuclk = container_of(nb, struct exynos_cpuclk, clk_nb); + base = cpuclk->ctrl_base; + + if (event == PRE_RATE_CHANGE) + err = exynos5433_cpuclk_pre_rate_change(ndata, cpuclk, base); + else if (event == POST_RATE_CHANGE) + err = exynos5433_cpuclk_post_rate_change(ndata, cpuclk, base); + + return notifier_from_errno(err); +} + /* helper function to register a CPU clock */ int __init exynos_register_cpu_clock(struct samsung_clk_provider *ctx, unsigned int lookup_id, const char *name, const char *parent, @@ -301,7 +427,10 @@ int __init exynos_register_cpu_clock(struct samsung_clk_provider *ctx, cpuclk->ctrl_base = ctx->reg_base + offset; cpuclk->lock = &ctx->lock; cpuclk->flags = flags; - cpuclk->clk_nb.notifier_call = exynos_cpuclk_notifier_cb; + if (flags & CLK_CPU_HAS_E5433_REGS_LAYOUT) + cpuclk->clk_nb.notifier_call = exynos5433_cpuclk_notifier_cb; + else + cpuclk->clk_nb.notifier_call = exynos_cpuclk_notifier_cb; cpuclk->alt_parent = __clk_lookup(alt_parent); if (!cpuclk->alt_parent) { diff --git a/drivers/clk/samsung/clk-cpu.h b/drivers/clk/samsung/clk-cpu.h index 37874d3c3165..d4b6b517fe1b 100644 --- a/drivers/clk/samsung/clk-cpu.h +++ b/drivers/clk/samsung/clk-cpu.h @@ -57,10 +57,12 @@ struct exynos_cpuclk { struct notifier_block clk_nb; unsigned long flags; -/* The CPU clock registers has DIV1 configuration register */ +/* The CPU clock registers have DIV1 configuration register */ #define CLK_CPU_HAS_DIV1 (1 << 0) /* When ALT parent is active, debug clocks need safe divider values */ #define CLK_CPU_NEEDS_DEBUG_ALT_DIV (1 << 1) +/* The CPU clock registers have Exynos5433-compatible layout */ +#define CLK_CPU_HAS_E5433_REGS_LAYOUT (1 << 2) }; extern int __init exynos_register_cpu_clock(struct samsung_clk_provider *ctx, -- 2.25.1