diff options
Diffstat (limited to 'drivers/clk/samsung/clk-pll.c')
| -rw-r--r-- | drivers/clk/samsung/clk-pll.c | 147 |
1 files changed, 71 insertions, 76 deletions
diff --git a/drivers/clk/samsung/clk-pll.c b/drivers/clk/samsung/clk-pll.c index ac70ad785d8e..5873a9354b50 100644 --- a/drivers/clk/samsung/clk-pll.c +++ b/drivers/clk/samsung/clk-pll.c @@ -8,14 +8,17 @@ #include <linux/errno.h> #include <linux/hrtimer.h> +#include <linux/iopoll.h> #include <linux/delay.h> #include <linux/slab.h> +#include <linux/timekeeping.h> #include <linux/clk-provider.h> #include <linux/io.h> #include "clk.h" #include "clk-pll.h" -#define PLL_TIMEOUT_MS 10 +#define PLL_TIMEOUT_US 20000U +#define PLL_TIMEOUT_LOOPS 1000000U struct samsung_clk_pll { struct clk_hw hw; @@ -63,6 +66,53 @@ static long samsung_pll_round_rate(struct clk_hw *hw, return rate_table[i - 1].rate; } +static bool pll_early_timeout = true; + +static int __init samsung_pll_disable_early_timeout(void) +{ + pll_early_timeout = false; + return 0; +} +arch_initcall(samsung_pll_disable_early_timeout); + +/* Wait until the PLL is locked */ +static int samsung_pll_lock_wait(struct samsung_clk_pll *pll, + unsigned int reg_mask) +{ + int i, ret; + u32 val; + + /* + * This function might be called when the timekeeping API can't be used + * to detect timeouts. One situation is when the clocksource is not yet + * initialized, another when the timekeeping is suspended. udelay() also + * cannot be used when the clocksource is not running on arm64, since + * the current timer is used as cycle counter. So a simple busy loop + * is used here in that special cases. The limit of iterations has been + * derived from experimental measurements of various PLLs on multiple + * Exynos SoC variants. Single register read time was usually in range + * 0.4...1.5 us, never less than 0.4 us. + */ + if (pll_early_timeout || timekeeping_suspended) { + i = PLL_TIMEOUT_LOOPS; + while (i-- > 0) { + if (readl_relaxed(pll->con_reg) & reg_mask) + return 0; + + cpu_relax(); + } + ret = -ETIMEDOUT; + } else { + ret = readl_relaxed_poll_timeout_atomic(pll->con_reg, val, + val & reg_mask, 0, PLL_TIMEOUT_US); + } + + if (ret < 0) + pr_err("Could not lock PLL %s\n", clk_hw_get_name(&pll->hw)); + + return ret; +} + static int samsung_pll3xxx_enable(struct clk_hw *hw) { struct samsung_clk_pll *pll = to_clk_pll(hw); @@ -72,13 +122,7 @@ static int samsung_pll3xxx_enable(struct clk_hw *hw) tmp |= BIT(pll->enable_offs); writel_relaxed(tmp, pll->con_reg); - /* wait lock time */ - do { - cpu_relax(); - tmp = readl_relaxed(pll->con_reg); - } while (!(tmp & BIT(pll->lock_offs))); - - return 0; + return samsung_pll_lock_wait(pll, BIT(pll->lock_offs)); } static void samsung_pll3xxx_disable(struct clk_hw *hw) @@ -240,13 +284,10 @@ static int samsung_pll35xx_set_rate(struct clk_hw *hw, unsigned long drate, (rate->sdiv << PLL35XX_SDIV_SHIFT); writel_relaxed(tmp, pll->con_reg); - /* Wait until the PLL is locked if it is enabled. */ - if (tmp & BIT(pll->enable_offs)) { - do { - cpu_relax(); - tmp = readl_relaxed(pll->con_reg); - } while (!(tmp & BIT(pll->lock_offs))); - } + /* Wait for PLL lock if the PLL is enabled */ + if (tmp & BIT(pll->enable_offs)) + return samsung_pll_lock_wait(pll, BIT(pll->lock_offs)); + return 0; } @@ -318,7 +359,7 @@ static int samsung_pll36xx_set_rate(struct clk_hw *hw, unsigned long drate, unsigned long parent_rate) { struct samsung_clk_pll *pll = to_clk_pll(hw); - u32 tmp, pll_con0, pll_con1; + u32 pll_con0, pll_con1; const struct samsung_pll_rate_table *rate; rate = samsung_get_pll_settings(pll, drate); @@ -356,13 +397,8 @@ static int samsung_pll36xx_set_rate(struct clk_hw *hw, unsigned long drate, pll_con1 |= rate->kdiv << PLL36XX_KDIV_SHIFT; writel_relaxed(pll_con1, pll->con_reg + 4); - /* wait_lock_time */ - if (pll_con0 & BIT(pll->enable_offs)) { - do { - cpu_relax(); - tmp = readl_relaxed(pll->con_reg); - } while (!(tmp & BIT(pll->lock_offs))); - } + if (pll_con0 & BIT(pll->enable_offs)) + return samsung_pll_lock_wait(pll, BIT(pll->lock_offs)); return 0; } @@ -437,7 +473,6 @@ static int samsung_pll45xx_set_rate(struct clk_hw *hw, unsigned long drate, struct samsung_clk_pll *pll = to_clk_pll(hw); const struct samsung_pll_rate_table *rate; u32 con0, con1; - ktime_t start; /* Get required rate settings from table */ rate = samsung_get_pll_settings(pll, drate); @@ -488,21 +523,8 @@ static int samsung_pll45xx_set_rate(struct clk_hw *hw, unsigned long drate, writel_relaxed(con1, pll->con_reg + 0x4); writel_relaxed(con0, pll->con_reg); - /* Wait for locking. */ - start = ktime_get(); - while (!(readl_relaxed(pll->con_reg) & PLL45XX_LOCKED)) { - ktime_t delta = ktime_sub(ktime_get(), start); - - if (ktime_to_ms(delta) > PLL_TIMEOUT_MS) { - pr_err("%s: could not lock PLL %s\n", - __func__, clk_hw_get_name(hw)); - return -EFAULT; - } - - cpu_relax(); - } - - return 0; + /* Wait for PLL lock */ + return samsung_pll_lock_wait(pll, PLL45XX_LOCKED); } static const struct clk_ops samsung_pll45xx_clk_ops = { @@ -588,7 +610,6 @@ static int samsung_pll46xx_set_rate(struct clk_hw *hw, unsigned long drate, struct samsung_clk_pll *pll = to_clk_pll(hw); const struct samsung_pll_rate_table *rate; u32 con0, con1, lock; - ktime_t start; /* Get required rate settings from table */ rate = samsung_get_pll_settings(pll, drate); @@ -647,21 +668,8 @@ static int samsung_pll46xx_set_rate(struct clk_hw *hw, unsigned long drate, writel_relaxed(con0, pll->con_reg); writel_relaxed(con1, pll->con_reg + 0x4); - /* Wait for locking. */ - start = ktime_get(); - while (!(readl_relaxed(pll->con_reg) & PLL46XX_LOCKED)) { - ktime_t delta = ktime_sub(ktime_get(), start); - - if (ktime_to_ms(delta) > PLL_TIMEOUT_MS) { - pr_err("%s: could not lock PLL %s\n", - __func__, clk_hw_get_name(hw)); - return -EFAULT; - } - - cpu_relax(); - } - - return 0; + /* Wait for PLL lock */ + return samsung_pll_lock_wait(pll, PLL46XX_LOCKED); } static const struct clk_ops samsung_pll46xx_clk_ops = { @@ -1035,14 +1043,9 @@ static int samsung_pll2550xx_set_rate(struct clk_hw *hw, unsigned long drate, (rate->sdiv << PLL2550XX_S_SHIFT); writel_relaxed(tmp, pll->con_reg); - /* wait_lock_time */ - do { - cpu_relax(); - tmp = readl_relaxed(pll->con_reg); - } while (!(tmp & (PLL2550XX_LOCK_STAT_MASK - << PLL2550XX_LOCK_STAT_SHIFT))); - - return 0; + /* Wait for PLL lock */ + return samsung_pll_lock_wait(pll, + PLL2550XX_LOCK_STAT_MASK << PLL2550XX_LOCK_STAT_SHIFT); } static const struct clk_ops samsung_pll2550xx_clk_ops = { @@ -1132,13 +1135,9 @@ static int samsung_pll2650x_set_rate(struct clk_hw *hw, unsigned long drate, con1 |= ((rate->kdiv & PLL2650X_K_MASK) << PLL2650X_K_SHIFT); writel_relaxed(con1, pll->con_reg + 4); - do { - cpu_relax(); - con0 = readl_relaxed(pll->con_reg); - } while (!(con0 & (PLL2650X_LOCK_STAT_MASK - << PLL2650X_LOCK_STAT_SHIFT))); - - return 0; + /* Wait for PLL lock */ + return samsung_pll_lock_wait(pll, + PLL2650X_LOCK_STAT_MASK << PLL2650X_LOCK_STAT_SHIFT); } static const struct clk_ops samsung_pll2650x_clk_ops = { @@ -1196,7 +1195,7 @@ static int samsung_pll2650xx_set_rate(struct clk_hw *hw, unsigned long drate, unsigned long parent_rate) { struct samsung_clk_pll *pll = to_clk_pll(hw); - u32 tmp, pll_con0, pll_con2; + u32 pll_con0, pll_con2; const struct samsung_pll_rate_table *rate; rate = samsung_get_pll_settings(pll, drate); @@ -1229,11 +1228,7 @@ static int samsung_pll2650xx_set_rate(struct clk_hw *hw, unsigned long drate, writel_relaxed(pll_con0, pll->con_reg); writel_relaxed(pll_con2, pll->con_reg + 8); - do { - tmp = readl_relaxed(pll->con_reg); - } while (!(tmp & (0x1 << PLL2650XX_PLL_LOCKTIME_SHIFT))); - - return 0; + return samsung_pll_lock_wait(pll, 0x1 << PLL2650XX_PLL_LOCKTIME_SHIFT); } static const struct clk_ops samsung_pll2650xx_clk_ops = { |