diff options
Diffstat (limited to 'target/linux/at91/patches-5.15/244-clk-at91-clk-master-add-notifier-for-divider.patch')
-rw-r--r-- | target/linux/at91/patches-5.15/244-clk-at91-clk-master-add-notifier-for-divider.patch | 519 |
1 files changed, 519 insertions, 0 deletions
diff --git a/target/linux/at91/patches-5.15/244-clk-at91-clk-master-add-notifier-for-divider.patch b/target/linux/at91/patches-5.15/244-clk-at91-clk-master-add-notifier-for-divider.patch new file mode 100644 index 0000000000..35262db6cb --- /dev/null +++ b/target/linux/at91/patches-5.15/244-clk-at91-clk-master-add-notifier-for-divider.patch @@ -0,0 +1,519 @@ +From 75d5d1d584ae73ba0c36d1d7255db6153ca4d3f3 Mon Sep 17 00:00:00 2001 +From: Claudiu Beznea <claudiu.beznea@microchip.com> +Date: Mon, 11 Oct 2021 14:27:16 +0300 +Subject: [PATCH 244/247] clk: at91: clk-master: add notifier for divider + +SAMA7G5 supports DVFS by changing cpuck. On SAMA7G5 mck0 shares the same +parent with cpuck as seen in the following clock tree: + + +----------> cpuck + | +FRAC PLL ---> DIV PLL -+-> DIV ---> mck0 + +mck0 could go b/w 32KHz and 200MHz on SAMA7G5. To avoid mck0 overclocking +while changing FRAC PLL or DIV PLL the commit implements a notifier for +mck0 which applies a safe divider to register (maximum value of the divider +which is 5) on PRE_RATE_CHANGE events (such that changes on PLL to not +overclock mck0) and sets the maximum allowed rate on POST_RATE_CHANGE +events. + +Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> +Link: https://lore.kernel.org/r/20211011112719.3951784-13-claudiu.beznea@microchip.com +Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com> +Signed-off-by: Stephen Boyd <sboyd@kernel.org> +--- + drivers/clk/at91/at91rm9200.c | 2 +- + drivers/clk/at91/at91sam9260.c | 2 +- + drivers/clk/at91/at91sam9g45.c | 2 +- + drivers/clk/at91/at91sam9n12.c | 2 +- + drivers/clk/at91/at91sam9rl.c | 2 +- + drivers/clk/at91/at91sam9x5.c | 2 +- + drivers/clk/at91/clk-master.c | 244 +++++++++++++++++++++++---------- + drivers/clk/at91/dt-compat.c | 2 +- + drivers/clk/at91/pmc.h | 2 +- + drivers/clk/at91/sama5d2.c | 2 +- + drivers/clk/at91/sama5d3.c | 2 +- + drivers/clk/at91/sama5d4.c | 2 +- + drivers/clk/at91/sama7g5.c | 2 +- + 13 files changed, 186 insertions(+), 82 deletions(-) + +--- a/drivers/clk/at91/at91rm9200.c ++++ b/drivers/clk/at91/at91rm9200.c +@@ -152,7 +152,7 @@ static void __init at91rm9200_pmc_setup( + "masterck_pres", + &at91rm9200_master_layout, + &rm9200_mck_characteristics, +- &rm9200_mck_lock, CLK_SET_RATE_GATE); ++ &rm9200_mck_lock, CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/at91sam9260.c ++++ b/drivers/clk/at91/at91sam9260.c +@@ -429,7 +429,7 @@ static void __init at91sam926x_pmc_setup + &at91rm9200_master_layout, + data->mck_characteristics, + &at91sam9260_mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/at91sam9g45.c ++++ b/drivers/clk/at91/at91sam9g45.c +@@ -164,7 +164,7 @@ static void __init at91sam9g45_pmc_setup + &at91rm9200_master_layout, + &mck_characteristics, + &at91sam9g45_mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/at91sam9n12.c ++++ b/drivers/clk/at91/at91sam9n12.c +@@ -191,7 +191,7 @@ static void __init at91sam9n12_pmc_setup + &at91sam9x5_master_layout, + &mck_characteristics, + &at91sam9n12_mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/at91sam9rl.c ++++ b/drivers/clk/at91/at91sam9rl.c +@@ -132,7 +132,7 @@ static void __init at91sam9rl_pmc_setup( + "masterck_pres", + &at91rm9200_master_layout, + &sam9rl_mck_characteristics, +- &sam9rl_mck_lock, CLK_SET_RATE_GATE); ++ &sam9rl_mck_lock, CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/at91sam9x5.c ++++ b/drivers/clk/at91/at91sam9x5.c +@@ -210,7 +210,7 @@ static void __init at91sam9x5_pmc_setup( + "masterck_pres", + &at91sam9x5_master_layout, + &mck_characteristics, &mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/clk-master.c ++++ b/drivers/clk/at91/clk-master.c +@@ -5,6 +5,7 @@ + + #include <linux/clk-provider.h> + #include <linux/clkdev.h> ++#include <linux/clk.h> + #include <linux/clk/at91_pmc.h> + #include <linux/of.h> + #include <linux/mfd/syscon.h> +@@ -36,8 +37,12 @@ struct clk_master { + u8 id; + u8 parent; + u8 div; ++ u32 safe_div; + }; + ++/* MCK div reference to be used by notifier. */ ++static struct clk_master *master_div; ++ + static inline bool clk_master_ready(struct clk_master *master) + { + unsigned int bit = master->id ? AT91_PMC_MCKXRDY : AT91_PMC_MCKRDY; +@@ -153,107 +158,81 @@ static const struct clk_ops master_div_o + .restore_context = clk_master_div_restore_context, + }; + +-static int clk_master_div_set_rate(struct clk_hw *hw, unsigned long rate, +- unsigned long parent_rate) ++/* This function must be called with lock acquired. */ ++static int clk_master_div_set(struct clk_master *master, ++ unsigned long parent_rate, int div) + { +- struct clk_master *master = to_clk_master(hw); + const struct clk_master_characteristics *characteristics = + master->characteristics; +- unsigned long flags; +- unsigned int mckr, tmp; +- int div, i; ++ unsigned long rate = parent_rate; ++ unsigned int max_div = 0, div_index = 0, max_div_index = 0; ++ unsigned int i, mckr, tmp; + int ret; + +- div = DIV_ROUND_CLOSEST(parent_rate, rate); +- if (div > ARRAY_SIZE(characteristics->divisors)) +- return -EINVAL; +- + for (i = 0; i < ARRAY_SIZE(characteristics->divisors); i++) { + if (!characteristics->divisors[i]) + break; + +- if (div == characteristics->divisors[i]) { +- div = i; +- break; ++ if (div == characteristics->divisors[i]) ++ div_index = i; ++ ++ if (max_div < characteristics->divisors[i]) { ++ max_div = characteristics->divisors[i]; ++ max_div_index = i; + } + } + +- if (i == ARRAY_SIZE(characteristics->divisors)) +- return -EINVAL; ++ if (div > max_div) ++ div_index = max_div_index; + +- spin_lock_irqsave(master->lock, flags); + ret = regmap_read(master->regmap, master->layout->offset, &mckr); + if (ret) +- goto unlock; ++ return ret; + + mckr &= master->layout->mask; + tmp = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; +- if (tmp == div) +- goto unlock; ++ if (tmp == div_index) ++ return 0; ++ ++ rate /= characteristics->divisors[div_index]; ++ if (rate < characteristics->output.min) ++ pr_warn("master clk div is underclocked"); ++ else if (rate > characteristics->output.max) ++ pr_warn("master clk div is overclocked"); + + mckr &= ~(MASTER_DIV_MASK << MASTER_DIV_SHIFT); +- mckr |= (div << MASTER_DIV_SHIFT); ++ mckr |= (div_index << MASTER_DIV_SHIFT); + ret = regmap_write(master->regmap, master->layout->offset, mckr); + if (ret) +- goto unlock; ++ return ret; + + while (!clk_master_ready(master)) + cpu_relax(); +-unlock: +- spin_unlock_irqrestore(master->lock, flags); ++ ++ master->div = characteristics->divisors[div_index]; + + return 0; + } + +-static int clk_master_div_determine_rate(struct clk_hw *hw, +- struct clk_rate_request *req) ++static unsigned long clk_master_div_recalc_rate_chg(struct clk_hw *hw, ++ unsigned long parent_rate) + { + struct clk_master *master = to_clk_master(hw); +- const struct clk_master_characteristics *characteristics = +- master->characteristics; +- struct clk_hw *parent; +- unsigned long parent_rate, tmp_rate, best_rate = 0; +- int i, best_diff = INT_MIN, tmp_diff; +- +- parent = clk_hw_get_parent(hw); +- if (!parent) +- return -EINVAL; +- +- parent_rate = clk_hw_get_rate(parent); +- if (!parent_rate) +- return -EINVAL; + +- for (i = 0; i < ARRAY_SIZE(characteristics->divisors); i++) { +- if (!characteristics->divisors[i]) +- break; +- +- tmp_rate = DIV_ROUND_CLOSEST_ULL(parent_rate, +- characteristics->divisors[i]); +- tmp_diff = abs(tmp_rate - req->rate); +- +- if (!best_rate || best_diff > tmp_diff) { +- best_diff = tmp_diff; +- best_rate = tmp_rate; +- } +- +- if (!best_diff) +- break; +- } +- +- req->best_parent_rate = best_rate; +- req->best_parent_hw = parent; +- req->rate = best_rate; +- +- return 0; ++ return DIV_ROUND_CLOSEST_ULL(parent_rate, master->div); + } + + static void clk_master_div_restore_context_chg(struct clk_hw *hw) + { + struct clk_master *master = to_clk_master(hw); ++ unsigned long flags; + int ret; + +- ret = clk_master_div_set_rate(hw, master->pms.rate, +- master->pms.parent_rate); ++ spin_lock_irqsave(master->lock, flags); ++ ret = clk_master_div_set(master, master->pms.parent_rate, ++ DIV_ROUND_CLOSEST(master->pms.parent_rate, ++ master->pms.rate)); ++ spin_unlock_irqrestore(master->lock, flags); + if (ret) + pr_warn("Failed to restore MCK DIV clock\n"); + } +@@ -261,13 +240,116 @@ static void clk_master_div_restore_conte + static const struct clk_ops master_div_ops_chg = { + .prepare = clk_master_prepare, + .is_prepared = clk_master_is_prepared, +- .recalc_rate = clk_master_div_recalc_rate, +- .determine_rate = clk_master_div_determine_rate, +- .set_rate = clk_master_div_set_rate, ++ .recalc_rate = clk_master_div_recalc_rate_chg, + .save_context = clk_master_div_save_context, + .restore_context = clk_master_div_restore_context_chg, + }; + ++static int clk_master_div_notifier_fn(struct notifier_block *notifier, ++ unsigned long code, void *data) ++{ ++ const struct clk_master_characteristics *characteristics = ++ master_div->characteristics; ++ struct clk_notifier_data *cnd = data; ++ unsigned long flags, new_parent_rate, new_rate; ++ unsigned int mckr, div, new_div = 0; ++ int ret, i; ++ long tmp_diff; ++ long best_diff = -1; ++ ++ spin_lock_irqsave(master_div->lock, flags); ++ switch (code) { ++ case PRE_RATE_CHANGE: ++ /* ++ * We want to avoid any overclocking of MCK DIV domain. To do ++ * this we set a safe divider (the underclocking is not of ++ * interest as we can go as low as 32KHz). The relation ++ * b/w this clock and its parents are as follows: ++ * ++ * FRAC PLL -> DIV PLL -> MCK DIV ++ * ++ * With the proper safe divider we should be good even with FRAC ++ * PLL at its maximum value. ++ */ ++ ret = regmap_read(master_div->regmap, master_div->layout->offset, ++ &mckr); ++ if (ret) { ++ ret = NOTIFY_STOP_MASK; ++ goto unlock; ++ } ++ ++ mckr &= master_div->layout->mask; ++ div = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; ++ ++ /* Switch to safe divider. */ ++ clk_master_div_set(master_div, ++ cnd->old_rate * characteristics->divisors[div], ++ master_div->safe_div); ++ break; ++ ++ case POST_RATE_CHANGE: ++ /* ++ * At this point we want to restore MCK DIV domain to its maximum ++ * allowed rate. ++ */ ++ ret = regmap_read(master_div->regmap, master_div->layout->offset, ++ &mckr); ++ if (ret) { ++ ret = NOTIFY_STOP_MASK; ++ goto unlock; ++ } ++ ++ mckr &= master_div->layout->mask; ++ div = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; ++ new_parent_rate = cnd->new_rate * characteristics->divisors[div]; ++ ++ for (i = 0; i < ARRAY_SIZE(characteristics->divisors); i++) { ++ if (!characteristics->divisors[i]) ++ break; ++ ++ new_rate = DIV_ROUND_CLOSEST_ULL(new_parent_rate, ++ characteristics->divisors[i]); ++ ++ tmp_diff = characteristics->output.max - new_rate; ++ if (tmp_diff < 0) ++ continue; ++ ++ if (best_diff < 0 || best_diff > tmp_diff) { ++ new_div = characteristics->divisors[i]; ++ best_diff = tmp_diff; ++ } ++ ++ if (!tmp_diff) ++ break; ++ } ++ ++ if (!new_div) { ++ ret = NOTIFY_STOP_MASK; ++ goto unlock; ++ } ++ ++ /* Update the div to preserve MCK DIV clock rate. */ ++ clk_master_div_set(master_div, new_parent_rate, ++ new_div); ++ ++ ret = NOTIFY_OK; ++ break; ++ ++ default: ++ ret = NOTIFY_DONE; ++ break; ++ } ++ ++unlock: ++ spin_unlock_irqrestore(master_div->lock, flags); ++ ++ return ret; ++} ++ ++static struct notifier_block clk_master_div_notifier = { ++ .notifier_call = clk_master_div_notifier_fn, ++}; ++ + static void clk_sama7g5_master_best_diff(struct clk_rate_request *req, + struct clk_hw *parent, + unsigned long parent_rate, +@@ -496,6 +578,8 @@ at91_clk_register_master_internal(struct + struct clk_master *master; + struct clk_init_data init; + struct clk_hw *hw; ++ unsigned int mckr; ++ unsigned long irqflags; + int ret; + + if (!name || !num_parents || !parent_names || !lock) +@@ -518,6 +602,16 @@ at91_clk_register_master_internal(struct + master->chg_pid = chg_pid; + master->lock = lock; + ++ if (ops == &master_div_ops_chg) { ++ spin_lock_irqsave(master->lock, irqflags); ++ regmap_read(master->regmap, master->layout->offset, &mckr); ++ spin_unlock_irqrestore(master->lock, irqflags); ++ ++ mckr &= layout->mask; ++ mckr = (mckr >> MASTER_DIV_SHIFT) & MASTER_DIV_MASK; ++ master->div = characteristics->divisors[mckr]; ++ } ++ + hw = &master->hw; + ret = clk_hw_register(NULL, &master->hw); + if (ret) { +@@ -554,19 +648,29 @@ at91_clk_register_master_div(struct regm + const char *name, const char *parent_name, + const struct clk_master_layout *layout, + const struct clk_master_characteristics *characteristics, +- spinlock_t *lock, u32 flags) ++ spinlock_t *lock, u32 flags, u32 safe_div) + { + const struct clk_ops *ops; ++ struct clk_hw *hw; + + if (flags & CLK_SET_RATE_GATE) + ops = &master_div_ops; + else + ops = &master_div_ops_chg; + +- return at91_clk_register_master_internal(regmap, name, 1, +- &parent_name, layout, +- characteristics, ops, +- lock, flags, -EINVAL); ++ hw = at91_clk_register_master_internal(regmap, name, 1, ++ &parent_name, layout, ++ characteristics, ops, ++ lock, flags, -EINVAL); ++ ++ if (!IS_ERR(hw) && safe_div) { ++ master_div = to_clk_master(hw); ++ master_div->safe_div = safe_div; ++ clk_notifier_register(hw->clk, ++ &clk_master_div_notifier); ++ } ++ ++ return hw; + } + + static unsigned long +--- a/drivers/clk/at91/dt-compat.c ++++ b/drivers/clk/at91/dt-compat.c +@@ -399,7 +399,7 @@ of_at91_clk_master_setup(struct device_n + + hw = at91_clk_register_master_div(regmap, name, "masterck_pres", + layout, characteristics, +- &mck_lock, CLK_SET_RATE_GATE); ++ &mck_lock, CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto out_free_characteristics; + +--- a/drivers/clk/at91/pmc.h ++++ b/drivers/clk/at91/pmc.h +@@ -182,7 +182,7 @@ at91_clk_register_master_div(struct regm + const char *parent_names, + const struct clk_master_layout *layout, + const struct clk_master_characteristics *characteristics, +- spinlock_t *lock, u32 flags); ++ spinlock_t *lock, u32 flags, u32 safe_div); + + struct clk_hw * __init + at91_clk_sama7g5_register_master(struct regmap *regmap, +--- a/drivers/clk/at91/sama5d2.c ++++ b/drivers/clk/at91/sama5d2.c +@@ -249,7 +249,7 @@ static void __init sama5d2_pmc_setup(str + "masterck_pres", + &at91sam9x5_master_layout, + &mck_characteristics, &mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/sama5d3.c ++++ b/drivers/clk/at91/sama5d3.c +@@ -184,7 +184,7 @@ static void __init sama5d3_pmc_setup(str + "masterck_pres", + &at91sam9x5_master_layout, + &mck_characteristics, &mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/sama5d4.c ++++ b/drivers/clk/at91/sama5d4.c +@@ -199,7 +199,7 @@ static void __init sama5d4_pmc_setup(str + "masterck_pres", + &at91sam9x5_master_layout, + &mck_characteristics, &mck_lock, +- CLK_SET_RATE_GATE); ++ CLK_SET_RATE_GATE, 0); + if (IS_ERR(hw)) + goto err_free; + +--- a/drivers/clk/at91/sama7g5.c ++++ b/drivers/clk/at91/sama7g5.c +@@ -1003,7 +1003,7 @@ static void __init sama7g5_pmc_setup(str + + hw = at91_clk_register_master_div(regmap, "mck0", "cpuck", + &mck0_layout, &mck0_characteristics, +- &pmc_mck0_lock, 0); ++ &pmc_mck0_lock, CLK_GET_RATE_NOCACHE, 5); + if (IS_ERR(hw)) + goto err_free; + |