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-rw-r--r--recipes/linux/linux-omap2-git/beagleboard/01-postrate-notifier.eml392
1 files changed, 392 insertions, 0 deletions
diff --git a/recipes/linux/linux-omap2-git/beagleboard/01-postrate-notifier.eml b/recipes/linux/linux-omap2-git/beagleboard/01-postrate-notifier.eml
new file mode 100644
index 0000000000..8e72afeb3f
--- /dev/null
+++ b/recipes/linux/linux-omap2-git/beagleboard/01-postrate-notifier.eml
@@ -0,0 +1,392 @@
+Add the infrastructure necessary to support clock post-rate-change notifiers
+in the OMAP clock framework. This includes:
+
+- adding the clk_notify_post_rate_chg() function, which will trigger a
+ notifier call chain when a clock rate is changed (but which currently
+ does nothing); and
+
+- adding calls to clk_notify_post_rate_chg() everywhere clk->rate is
+ assigned (mostly *_recalc() functions).
+
+This patch has no functional effect by itself; the actual notifier
+implementation follows in a separate patch.
+
+One item to note is that the post-rate-change notifier is called even
+if the new clock rate is identical to the old rate. This is because
+the process of changing the rate may have temporarily disabled or
+glitched the clock or one of its parents, and some devices may be
+sensitive to such changes.
+
+Signed-off-by: Paul Walmsley <paul@pwsan.com>
+---
+
+ arch/arm/mach-omap2/clock.c | 37 +++++++++++++++++++++++++++------
+ arch/arm/mach-omap2/clock24xx.c | 42 +++++++++++++++++++++++++++++++++++--
+ arch/arm/mach-omap2/clock34xx.c | 10 +++++++++
+ arch/arm/plat-omap/clock.c | 32 ++++++++++++++++++++++++++++
+ include/asm-arm/arch-omap/clock.h | 21 +++++++++++++++++++
+ 5 files changed, 134 insertions(+), 8 deletions(-)
+
+diff --git a/arch/arm/mach-omap2/clock.c b/arch/arm/mach-omap2/clock.c
+index ed15868..bd3c1f8 100644
+--- a/arch/arm/mach-omap2/clock.c
++++ b/arch/arm/mach-omap2/clock.c
+@@ -165,10 +165,15 @@ u32 omap2_get_dpll_rate(struct clk *clk)
+ */
+ void omap2_fixed_divisor_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
+ WARN_ON(!clk->fixed_div);
+
++ orig_rate = clk->rate;
+ clk->rate = clk->parent->rate / clk->fixed_div;
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ if (clk->flags & RATE_PROPAGATES)
+ propagate_rate(clk);
+ }
+@@ -376,6 +381,7 @@ int omap2_clk_enable(struct clk *clk)
+ void omap2_clksel_recalc(struct clk *clk)
+ {
+ u32 div = 0;
++ unsigned long orig_rate;
+
+ pr_debug("clock: recalc'ing clksel clk %s\n", clk->name);
+
+@@ -385,10 +391,13 @@ void omap2_clksel_recalc(struct clk *clk)
+
+ if (clk->rate == (clk->parent->rate / div))
+ return;
++ orig_rate = clk->rate;
+ clk->rate = clk->parent->rate / div;
+
+ pr_debug("clock: new clock rate is %ld (div %d)\n", clk->rate, div);
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ if (clk->flags & RATE_PROPAGATES)
+ propagate_rate(clk);
+ }
+@@ -662,6 +671,8 @@ int omap2_clksel_set_rate(struct clk *clk, unsigned long rate)
+ wmb();
+ }
+
++ /* post-rate-change notifier will be called by omap2_clk_set_rate() */
++
+ return 0;
+ }
+
+@@ -670,20 +681,30 @@ int omap2_clksel_set_rate(struct clk *clk, unsigned long rate)
+ int omap2_clk_set_rate(struct clk *clk, unsigned long rate)
+ {
+ int ret = -EINVAL;
+-
+- pr_debug("clock: set_rate for clock %s to rate %ld\n", clk->name, rate);
++ unsigned long orig_rate;
+
+ /* CONFIG_PARTICIPANT clocks are changed only in sets via the
+ rate table mechanism, driven by mpu_speed */
+ if (clk->flags & CONFIG_PARTICIPANT)
+ return -EINVAL;
+
++ if (!clk->set_rate)
++ return -EINVAL;
++
++ orig_rate = clk->rate;
++
++ pr_debug("clock: set_rate for clock %s from %ld Hz to %ld Hz\n",
++ clk->name, orig_rate, rate);
++
+ /* dpll_ck, core_ck, virt_prcm_set; plus all clksel clocks */
+- if (clk->set_rate)
+- ret = clk->set_rate(clk, rate);
++ ret = clk->set_rate(clk, rate);
+
+- if (ret == 0 && (clk->flags & RATE_PROPAGATES))
+- propagate_rate(clk);
++ if (ret == 0) {
++ clk_notify_post_rate_chg(clk, orig_rate, rate);
++
++ if (clk->flags & RATE_PROPAGATES)
++ propagate_rate(clk);
++ }
+
+ return ret;
+ }
+@@ -732,6 +753,7 @@ int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
+ {
+ void __iomem *src_addr;
+ u32 field_val, field_mask, reg_val, parent_div;
++ unsigned long orig_rate;
+
+ if (clk->flags & CONFIG_PARTICIPANT)
+ return -EINVAL;
+@@ -765,11 +787,14 @@ int omap2_clk_set_parent(struct clk *clk, struct clk *new_parent)
+ clk->parent = new_parent;
+
+ /* CLKSEL clocks follow their parents' rates, divided by a divisor */
++ orig_rate = clk->rate;
+ clk->rate = new_parent->rate;
+
+ if (parent_div > 0)
+ clk->rate /= parent_div;
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
+ clk->name, clk->parent->name, clk->rate);
+
+diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c
+index 54cc6e1..e001549 100644
+--- a/arch/arm/mach-omap2/clock24xx.c
++++ b/arch/arm/mach-omap2/clock24xx.c
+@@ -172,11 +172,22 @@ static long omap2_dpllcore_round_rate(unsigned long target_rate)
+
+ static void omap2_dpllcore_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
++ orig_rate = clk->rate;
+ clk->rate = omap2_get_dpll_rate_24xx(clk);
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ propagate_rate(clk);
+ }
+
++/*
++ * XXX REVISIT: This code needs to keep track of the underlying struct
++ * clocks that it is changing, so it can call post-rate-change notifiers
++ * on them. This function probably should be rewritten to use the clock
++ * fw.
++ */
+ static int omap2_reprogram_dpllcore(struct clk *clk, unsigned long rate)
+ {
+ u32 cur_rate, low, mult, div, valid_rate, done_rate;
+@@ -259,7 +270,14 @@ dpll_exit:
+ */
+ static void omap2_table_mpu_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
++ orig_rate = clk->rate;
+ clk->rate = curr_prcm_set->mpu_speed;
++
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
++ /* No rate propagation since table clocks have no children */
+ }
+
+ /*
+@@ -294,7 +312,14 @@ static long omap2_round_to_table_rate(struct clk *clk, unsigned long rate)
+ return highest_rate;
+ }
+
+-/* Sets basic clocks based on the specified rate */
++/*
++ * Sets basic clocks based on the specified rate
++ *
++ * XXX REVISIT: This code needs to keep track of the underlying struct
++ * clocks that it is changing, so it can call post-rate-change notifiers
++ * on them. This function probably should be rewritten to use the clock
++ * fw.
++ */
+ static int omap2_select_table_rate(struct clk *clk, unsigned long rate)
+ {
+ u32 cur_rate, done_rate, bypass = 0, tmp;
+@@ -353,7 +378,8 @@ static int omap2_select_table_rate(struct clk *clk, unsigned long rate)
+ cm_write_mod_reg(prcm->cm_clksel_gfx, GFX_MOD, CM_CLKSEL);
+
+ /* Major subsystem dividers */
+- tmp = cm_read_mod_reg(CORE_MOD, CM_CLKSEL1) & OMAP24XX_CLKSEL_DSS2_MASK;
++ tmp = cm_read_mod_reg(CORE_MOD, CM_CLKSEL1) &
++ OMAP24XX_CLKSEL_DSS2_MASK;
+ cm_write_mod_reg(prcm->cm_clksel1_core | tmp, CORE_MOD,
+ CM_CLKSEL1);
+
+@@ -460,13 +486,25 @@ static u32 omap2_get_sysclkdiv(void)
+
+ static void omap2_osc_clk_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
++ orig_rate = clk->rate;
+ clk->rate = omap2_get_apll_clkin() * omap2_get_sysclkdiv();
++
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ propagate_rate(clk);
+ }
+
+ static void omap2_sys_clk_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
++ orig_rate = clk->rate;
+ clk->rate = clk->parent->rate / omap2_get_sysclkdiv();
++
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ propagate_rate(clk);
+ }
+
+diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c
+index 408b51a..7b89b61 100644
+--- a/arch/arm/mach-omap2/clock34xx.c
++++ b/arch/arm/mach-omap2/clock34xx.c
+@@ -53,8 +53,13 @@
+ */
+ static void omap3_dpll_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
++ orig_rate = clk->rate;
+ clk->rate = omap2_get_dpll_rate(clk);
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ propagate_rate(clk);
+ }
+
+@@ -500,6 +505,7 @@ static void omap3_clkoutx2_recalc(struct clk *clk)
+ const struct dpll_data *dd;
+ u32 v;
+ struct clk *pclk;
++ unsigned long orig_rate;
+
+ /* Walk up the parents of clk, looking for a DPLL */
+ pclk = clk->parent;
+@@ -513,6 +519,8 @@ static void omap3_clkoutx2_recalc(struct clk *clk)
+
+ WARN_ON(!dd->control_reg || !dd->enable_mask);
+
++ orig_rate = clk->rate;
++
+ v = __raw_readl(dd->control_reg) & dd->enable_mask;
+ v >>= __ffs(dd->enable_mask);
+ if (v != DPLL_LOCKED)
+@@ -520,6 +528,8 @@ static void omap3_clkoutx2_recalc(struct clk *clk)
+ else
+ clk->rate = clk->parent->rate * 2;
+
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ if (clk->flags & RATE_PROPAGATES)
+ propagate_rate(clk);
+ }
+diff --git a/arch/arm/plat-omap/clock.c b/arch/arm/plat-omap/clock.c
+index c2e741d..421d076 100644
+--- a/arch/arm/plat-omap/clock.c
++++ b/arch/arm/plat-omap/clock.c
+@@ -254,10 +254,16 @@ __setup("mpurate=", omap_clk_setup);
+ /* Used for clocks that always have same value as the parent clock */
+ void followparent_recalc(struct clk *clk)
+ {
++ unsigned long orig_rate;
++
+ if (clk == NULL || IS_ERR(clk))
+ return;
+
++ orig_rate = clk->rate;
+ clk->rate = clk->parent->rate;
++
++ clk_notify_post_rate_chg(clk, orig_rate, clk->rate);
++
+ if (unlikely(clk->flags & RATE_PROPAGATES))
+ propagate_rate(clk);
+ }
+@@ -373,6 +379,32 @@ void clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
+ EXPORT_SYMBOL(clk_init_cpufreq_table);
+ #endif
+
++/**
++ * clk_notify_post_rate_chg - call post-clk-rate-change notifier chain
++ * @clk: struct clk * that is changing rate
++ * @old_rate: old rate
++ * @new_rate: new rate
++ *
++ * Triggers a notifier call chain on the post-clk-rate-change notifier
++ * for clock 'clk'. Passes a pointer to the struct clk and the
++ * previous and current rates to the notifier callback. Intended to be
++ * called by internal clock code only. No return value.
++ */
++void clk_notify_post_rate_chg(struct clk *clk, unsigned long old_rate,
++ unsigned long new_rate)
++{
++ struct clk_notifier *cn;
++ struct clk_notifier_data cnd;
++
++ cnd.clk = clk;
++ cnd.old_rate = old_rate;
++ cnd.new_rate = new_rate;
++
++ /* XXX Call notifier here */
++
++}
++
++
+ /*-------------------------------------------------------------------------*/
+
+ #ifdef CONFIG_OMAP_RESET_CLOCKS
+diff --git a/include/asm-arm/arch-omap/clock.h b/include/asm-arm/arch-omap/clock.h
+index bfaf7b6..e3c9aeb 100644
+--- a/include/asm-arm/arch-omap/clock.h
++++ b/include/asm-arm/arch-omap/clock.h
+@@ -10,6 +10,8 @@
+ * published by the Free Software Foundation.
+ */
+
++#include <linux/notifier.h>
++
+ #ifndef __ARCH_ARM_OMAP_CLOCK_H
+ #define __ARCH_ARM_OMAP_CLOCK_H
+
+@@ -58,6 +60,19 @@ struct dpll_data {
+
+ #endif
+
++struct clk_notifier {
++ struct clk *clk;
++ struct atomic_notifier_head notifier_head;
++ struct list_head node;
++};
++
++struct clk_notifier_data {
++ struct clk *clk;
++ unsigned long old_rate;
++ unsigned long new_rate;
++};
++
++
+ struct clk {
+ struct list_head node;
+ struct module *owner;
+@@ -121,6 +136,10 @@ extern void clk_allow_idle(struct clk *clk);
+ extern void clk_deny_idle(struct clk *clk);
+ extern int clk_get_usecount(struct clk *clk);
+ extern void clk_enable_init_clocks(void);
++extern int clk_notifier_register(struct clk *clk, struct notifier_block *nb);
++extern int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb);
++extern void clk_notify_post_rate_chg(struct clk *clk, unsigned long old_rate,
++ unsigned long new_rate);
+ #ifdef CONFIG_CPU_FREQ
+ extern void clk_init_cpufreq_table(struct cpufreq_frequency_table **table);
+ #endif
+@@ -161,6 +180,8 @@ extern void clk_init_cpufreq_table(struct cpufreq_frequency_table **table);
+
+ #define RATE_IN_24XX (RATE_IN_242X | RATE_IN_243X)
+
++/* Clk rate change notifier callback type */
++#define CLK_POST_RATE_CHANGE 1
+
+ /* CM_CLKSEL2_PLL.CORE_CLK_SRC options (24XX) */
+ #define CORE_CLK_SRC_32K 0
+
+
+--
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+
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-06-05 22:03:23 +0000