[PATCH v2 10/21] ARM: tegra: clock: Convert global lock to a lock per clock

From: Colin Cross
Date: Sat Feb 19 2011 - 17:26:52 EST

Next message: Colin Cross: "[PATCH v2 09/21] ARM: tegra: clock: Move unshared clk struct members into union"
Previous message: Colin Cross: "[PATCH v2 12/21] ARM: tegra: clock: Add shared bus clock type"
In reply to: Colin Cross: "[PATCH v2 12/21] ARM: tegra: clock: Add shared bus clock type"
Next in thread: Olof Johansson: "Re: [PATCH v2 10/21] ARM: tegra: clock: Convert global lock to a lockper clock"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Give each clock its own lock, and remove all lock traversals from
parent to child clocks to prevent AB-BA deadlocks.

This brings the locking in line with the common struct clk
patches and should make conversion simple.

Signed-off-by: Colin Cross <ccross@xxxxxxxxxxx>
---
arch/arm/mach-tegra/clock.c | 358 ++++++++++++++++++++------------
arch/arm/mach-tegra/clock.h | 14 +-
arch/arm/mach-tegra/include/mach/clk.h | 1 +
arch/arm/mach-tegra/tegra2_clocks.c | 119 ++++++++---
4 files changed, 322 insertions(+), 170 deletions(-)

diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
index a1193f9..f6c934a 100644
--- a/arch/arm/mach-tegra/clock.c
+++ b/arch/arm/mach-tegra/clock.c
@@ -18,83 +18,117 @@

#include <linux/kernel.h>
#include <linux/clk.h>
-#include <linux/list.h>
+#include <linux/clkdev.h>
+#include <linux/debugfs.h>
+#include <linux/delay.h>
#include <linux/init.h>
+#include <linux/list.h>
#include <linux/module.h>
-#include <linux/debugfs.h>
-#include <linux/slab.h>
+#include <linux/sched.h>
#include <linux/seq_file.h>
-#include <linux/clkdev.h>
+#include <linux/slab.h>
+
+#include <mach/clk.h>

#include "board.h"
#include "clock.h"

+/*
+ * Locking:
+ *
+ * Each struct clk has a spinlock.
+ *
+ * To avoid AB-BA locking problems, locks must always be traversed from child
+ * clock to parent clock. For example, when enabling a clock, the clock's lock
+ * is taken, and then clk_enable is called on the parent, which take's the
+ * parent clock's lock. There is one exceptions to this ordering: When dumping
+ * the clock tree through debugfs. In this case, clk_lock_all is called,
+ * which attemps to iterate through the entire list of clocks and take every
+ * clock lock. If any call to spin_trylock fails, all locked clocks are
+ * unlocked, and the process is retried. When all the locks are held,
+ * the only clock operation that can be called is clk_get_rate_all_locked.
+ *
+ * Within a single clock, no clock operation can call another clock operation
+ * on itself, except for clk_get_rate_locked and clk_set_rate_locked. Any
+ * clock operation can call any other clock operation on any of it's possible
+ * parents.
+ *
+ * An additional mutex, clock_list_lock, is used to protect the list of all
+ * clocks.
+ *
+ * The clock operations must lock internally to protect against
+ * read-modify-write on registers that are shared by multiple clocks
+ */
+static DEFINE_MUTEX(clock_list_lock);
static LIST_HEAD(clocks);

-static DEFINE_SPINLOCK(clock_lock);
struct clk *tegra_get_clock_by_name(const char *name)
{
struct clk *c;
struct clk *ret = NULL;
- unsigned long flags;
- spin_lock_irqsave(&clock_lock, flags);
+ mutex_lock(&clock_list_lock);
list_for_each_entry(c, &clocks, node) {
if (strcmp(c->name, name) == 0) {
ret = c;
break;
}
}
- spin_unlock_irqrestore(&clock_lock, flags);
+ mutex_unlock(&clock_list_lock);
return ret;
}

-static void clk_recalculate_rate(struct clk *c)
+/* Must be called with c->spinlock held */
+static unsigned long clk_predict_rate_from_parent(struct clk *c, struct clk *p)
{
u64 rate;

- if (!c->parent)
- return;
-
- rate = c->parent->rate;
+ rate = clk_get_rate(p);

if (c->mul != 0 && c->div != 0) {
- rate = rate * c->mul;
+ rate *= c->mul;
do_div(rate, c->div);
}

- if (rate > c->max_rate)
- pr_warn("clocks: Set clock %s to rate %llu, max is %lu\n",
- c->name, rate, c->max_rate);
-
- c->rate = rate;
+ return rate;
}

-int clk_reparent(struct clk *c, struct clk *parent)
+/* Must be called with c->spinlock held */
+unsigned long clk_get_rate_locked(struct clk *c)
{
- c->parent = parent;
- list_del(&c->sibling);
- list_add_tail(&c->sibling, &parent->children);
- return 0;
-}
+ unsigned long rate;

-static void propagate_rate(struct clk *c)
-{
- struct clk *clkp;
+ if (c->parent)
+ rate = clk_predict_rate_from_parent(c, c->parent);
+ else
+ rate = c->rate;

- list_for_each_entry(clkp, &c->children, sibling) {
- clk_recalculate_rate(clkp);
- propagate_rate(clkp);
- }
+ return rate;
}

-void clk_init(struct clk *c)
+unsigned long clk_get_rate(struct clk *c)
{
unsigned long flags;
+ unsigned long rate;

- spin_lock_irqsave(&clock_lock, flags);
+ spin_lock_irqsave(&c->spinlock, flags);

- INIT_LIST_HEAD(&c->children);
- INIT_LIST_HEAD(&c->sibling);
+ rate = clk_get_rate_locked(c);
+
+ spin_unlock_irqrestore(&c->spinlock, flags);
+
+ return rate;
+}
+EXPORT_SYMBOL(clk_get_rate);
+
+int clk_reparent(struct clk *c, struct clk *parent)
+{
+ c->parent = parent;
+ return 0;
+}
+
+void clk_init(struct clk *c)
+{
+ spin_lock_init(&c->spinlock);

if (c->ops && c->ops->init)
c->ops->init(c);
@@ -108,33 +142,31 @@ void clk_init(struct clk *c)
c->state = ON;
}

- clk_recalculate_rate(c);
-
+ mutex_lock(&clock_list_lock);
list_add(&c->node, &clocks);
-
- if (c->parent)
- list_add_tail(&c->sibling, &c->parent->children);
-
- spin_unlock_irqrestore(&clock_lock, flags);
+ mutex_unlock(&clock_list_lock);
}

-int clk_enable_locked(struct clk *c)
+int clk_enable(struct clk *c)
{
- int ret;
+ int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&c->spinlock, flags);

if (c->refcnt == 0) {
if (c->parent) {
- ret = clk_enable_locked(c->parent);
+ ret = clk_enable(c->parent);
if (ret)
- return ret;
+ goto out;
}

if (c->ops && c->ops->enable) {
ret = c->ops->enable(c);
if (ret) {
if (c->parent)
- clk_disable_locked(c->parent);
- return ret;
+ clk_disable(c->parent);
+ goto out;
}
c->state = ON;
#ifdef CONFIG_DEBUG_FS
@@ -143,27 +175,21 @@ int clk_enable_locked(struct clk *c)
}
}
c->refcnt++;
-
- return 0;
+out:
+ spin_unlock_irqrestore(&c->spinlock, flags);
+ return ret;
}
+EXPORT_SYMBOL(clk_enable);

-int clk_enable(struct clk *c)
+void clk_disable(struct clk *c)
{
- int ret;
unsigned long flags;

- spin_lock_irqsave(&clock_lock, flags);
- ret = clk_enable_locked(c);
- spin_unlock_irqrestore(&clock_lock, flags);
+ spin_lock_irqsave(&c->spinlock, flags);

- return ret;
-}
-EXPORT_SYMBOL(clk_enable);
-
-void clk_disable_locked(struct clk *c)
-{
if (c->refcnt == 0) {
WARN(1, "Attempting to disable clock %s with refcnt 0", c->name);
+ spin_unlock_irqrestore(&c->spinlock, flags);
return;
}
if (c->refcnt == 1) {
@@ -171,49 +197,39 @@ void clk_disable_locked(struct clk *c)
c->ops->disable(c);

if (c->parent)
- clk_disable_locked(c->parent);
+ clk_disable(c->parent);

c->state = OFF;
}
c->refcnt--;
-}

-void clk_disable(struct clk *c)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&clock_lock, flags);
- clk_disable_locked(c);
- spin_unlock_irqrestore(&clock_lock, flags);
+ spin_unlock_irqrestore(&c->spinlock, flags);
}
EXPORT_SYMBOL(clk_disable);

-int clk_set_parent_locked(struct clk *c, struct clk *parent)
+int clk_set_parent(struct clk *c, struct clk *parent)
{
int ret;
+ unsigned long flags;
+ unsigned long new_rate;
+ unsigned long old_rate;

- if (!c->ops || !c->ops->set_parent)
- return -ENOSYS;
+ spin_lock_irqsave(&c->spinlock, flags);

- ret = c->ops->set_parent(c, parent);
-
- if (ret)
- return ret;
-
- clk_recalculate_rate(c);
+ if (!c->ops || !c->ops->set_parent) {
+ ret = -ENOSYS;
+ goto out;
+ }

- propagate_rate(c);
+ new_rate = clk_predict_rate_from_parent(c, parent);
+ old_rate = clk_get_rate_locked(c);

- return 0;
-}
+ ret = c->ops->set_parent(c, parent);
+ if (ret)
+ goto out;

-int clk_set_parent(struct clk *c, struct clk *parent)
-{
- int ret;
- unsigned long flags;
- spin_lock_irqsave(&clock_lock, flags);
- ret = clk_set_parent_locked(c, parent);
- spin_unlock_irqrestore(&clock_lock, flags);
+out:
+ spin_unlock_irqrestore(&c->spinlock, flags);
return ret;
}
EXPORT_SYMBOL(clk_set_parent);
@@ -226,62 +242,75 @@ EXPORT_SYMBOL(clk_get_parent);

int clk_set_rate_locked(struct clk *c, unsigned long rate)
{
- int ret;
-
- if (rate > c->max_rate)
- rate = c->max_rate;
-
if (!c->ops || !c->ops->set_rate)
return -ENOSYS;

- ret = c->ops->set_rate(c, rate);
-
- if (ret)
- return ret;
-
- clk_recalculate_rate(c);
-
- propagate_rate(c);
+ if (rate > c->max_rate)
+ rate = c->max_rate;

- return 0;
+ return c->ops->set_rate(c, rate);
}

int clk_set_rate(struct clk *c, unsigned long rate)
{
- int ret = 0;
+ int ret;
unsigned long flags;

- spin_lock_irqsave(&clock_lock, flags);
+ spin_lock_irqsave(&c->spinlock, flags);
+
ret = clk_set_rate_locked(c, rate);
- spin_unlock_irqrestore(&clock_lock, flags);
+
+ spin_unlock_irqrestore(&c->spinlock, flags);

return ret;
}
EXPORT_SYMBOL(clk_set_rate);

-unsigned long clk_get_rate(struct clk *c)
-{
- unsigned long flags;
- unsigned long ret;

- spin_lock_irqsave(&clock_lock, flags);
+/* Must be called with clocks lock and all indvidual clock locks held */
+unsigned long clk_get_rate_all_locked(struct clk *c)
+{
+ u64 rate;
+ int mul = 1;
+ int div = 1;
+ struct clk *p = c;
+
+ while (p) {
+ c = p;
+ if (c->mul != 0 && c->div != 0) {
+ mul *= c->mul;
+ div *= c->div;
+ }
+ p = c->parent;
+ }

- ret = c->rate;
+ rate = c->rate;
+ rate *= mul;
+ do_div(rate, div);

- spin_unlock_irqrestore(&clock_lock, flags);
- return ret;
+ return rate;
}
-EXPORT_SYMBOL(clk_get_rate);

long clk_round_rate(struct clk *c, unsigned long rate)
{
- if (!c->ops || !c->ops->round_rate)
- return -ENOSYS;
+ unsigned long flags;
+ long ret;
+
+ spin_lock_irqsave(&c->spinlock, flags);
+
+ if (!c->ops || !c->ops->round_rate) {
+ ret = -ENOSYS;
+ goto out;
+ }

if (rate > c->max_rate)
rate = c->max_rate;

- return c->ops->round_rate(c, rate);
+ ret = c->ops->round_rate(c, rate);
+
+out:
+ spin_unlock_irqrestore(&c->spinlock, flags);
+ return ret;
}
EXPORT_SYMBOL(clk_round_rate);

@@ -374,9 +403,10 @@ int __init tegra_disable_boot_clocks(void)

struct clk *c;

- spin_lock_irqsave(&clock_lock, flags);
+ mutex_lock(&clock_list_lock);

list_for_each_entry(c, &clocks, node) {
+ spin_lock_irqsave(&c->spinlock, flags);
if (c->refcnt == 0 && c->state == ON &&
c->ops && c->ops->disable) {
pr_warning("Disabling clock %s left on by bootloader\n",
@@ -384,23 +414,85 @@ int __init tegra_disable_boot_clocks(void)
c->ops->disable(c);
c->state = OFF;
}
+ spin_unlock_irqrestore(&c->spinlock, flags);
}

- spin_unlock_irqrestore(&clock_lock, flags);
-
+ mutex_unlock(&clock_list_lock);
return 0;
}
late_initcall(tegra_disable_boot_clocks);
#endif

#ifdef CONFIG_DEBUG_FS
+
+static int __clk_lock_all_spinlocks(void)
+{
+ struct clk *c;
+
+ list_for_each_entry(c, &clocks, node)
+ if (!spin_trylock(&c->spinlock))
+ goto unlock_spinlocks;
+
+ return 0;
+
+unlock_spinlocks:
+ list_for_each_entry_continue_reverse(c, &clocks, node)
+ spin_unlock(&c->spinlock);
+
+ return -EAGAIN;
+}
+
+static void __clk_unlock_all_spinlocks(void)
+{
+ struct clk *c;
+
+ list_for_each_entry_reverse(c, &clocks, node)
+ spin_unlock(&c->spinlock);
+}
+
+/*
+ * This function retries until it can take all locks, and may take
+ * an arbitrarily long time to complete.
+ * Must be called with irqs enabled, returns with irqs disabled
+ * Must be called with clock_list_lock held
+ */
+static void clk_lock_all(void)
+{
+ int ret;
+retry:
+ local_irq_disable();
+
+ ret = __clk_lock_all_spinlocks();
+ if (ret)
+ goto failed_spinlocks;
+
+ /* All locks taken successfully, return */
+ return;
+
+failed_spinlocks:
+ local_irq_enable();
+ yield();
+ goto retry;
+}
+
+/*
+ * Unlocks all clocks after a clk_lock_all
+ * Must be called with irqs disabled, returns with irqs enabled
+ * Must be called with clock_list_lock held
+ */
+static void clk_unlock_all(void)
+{
+ __clk_unlock_all_spinlocks();
+
+ local_irq_enable();
+}
+
static struct dentry *clk_debugfs_root;

static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
{
struct clk *child;
- struct clk *safe;
const char *state = "uninit";
char div[8] = {0};

@@ -431,8 +523,12 @@ static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
c->rate > c->max_rate ? '!' : ' ',
!c->set ? '*' : ' ',
30 - level * 3, c->name,
- state, c->refcnt, div, c->rate);
- list_for_each_entry_safe(child, safe, &c->children, sibling) {
+ state, c->refcnt, div, clk_get_rate_all_locked(c));
+
+ list_for_each_entry(child, &clocks, node) {
+ if (child->parent != c)
+ continue;
+
clock_tree_show_one(s, child, level + 1);
}
}
@@ -440,14 +536,20 @@ static void clock_tree_show_one(struct seq_file *s, struct clk *c, int level)
static int clock_tree_show(struct seq_file *s, void *data)
{
struct clk *c;
- unsigned long flags;
seq_printf(s, " clock state ref div rate\n");
seq_printf(s, "--------------------------------------------------------------\n");
- spin_lock_irqsave(&clock_lock, flags);
+
+ mutex_lock(&clock_list_lock);
+
+ clk_lock_all();
+
list_for_each_entry(c, &clocks, node)
if (c->parent == NULL)
clock_tree_show_one(s, c, 0);
- spin_unlock_irqrestore(&clock_lock, flags);
+
+ clk_unlock_all();
+
+ mutex_unlock(&clock_list_lock);
return 0;
}

diff --git a/arch/arm/mach-tegra/clock.h b/arch/arm/mach-tegra/clock.h
index 20f0ce6..a63dbf9 100644
--- a/arch/arm/mach-tegra/clock.h
+++ b/arch/arm/mach-tegra/clock.h
@@ -20,8 +20,9 @@
#ifndef __MACH_TEGRA_CLOCK_H
#define __MACH_TEGRA_CLOCK_H

-#include <linux/list.h>
#include <linux/clkdev.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>

#define DIV_BUS (1 << 0)
#define DIV_U71 (1 << 1)
@@ -75,8 +76,6 @@ enum clk_state {
struct clk {
/* node for master clocks list */
struct list_head node; /* node for list of all clocks */
- struct list_head children; /* list of children */
- struct list_head sibling; /* node for children */
struct clk_lookup lookup;

#ifdef CONFIG_DEBUG_FS
@@ -122,8 +121,9 @@ struct clk {
struct clk *backup;
} cpu;
} u;
-};

+ spinlock_t spinlock;
+};

struct clk_duplicate {
const char *name;
@@ -143,11 +143,9 @@ void tegra2_periph_reset_assert(struct clk *c);
void clk_init(struct clk *clk);
struct clk *tegra_get_clock_by_name(const char *name);
unsigned long clk_measure_input_freq(void);
-void clk_disable_locked(struct clk *c);
-int clk_enable_locked(struct clk *c);
-int clk_set_parent_locked(struct clk *c, struct clk *parent);
-int clk_set_rate_locked(struct clk *c, unsigned long rate);
int clk_reparent(struct clk *c, struct clk *parent);
void tegra_clk_init_from_table(struct tegra_clk_init_table *table);
+unsigned long clk_get_rate_locked(struct clk *c);
+int clk_set_rate_locked(struct clk *c, unsigned long rate);

#endif
diff --git a/arch/arm/mach-tegra/include/mach/clk.h b/arch/arm/mach-tegra/include/mach/clk.h
index 6338652..fa7f9ca 100644
--- a/arch/arm/mach-tegra/include/mach/clk.h
+++ b/arch/arm/mach-tegra/include/mach/clk.h
@@ -25,4 +25,5 @@ struct clk;
void tegra_periph_reset_deassert(struct clk *c);
void tegra_periph_reset_assert(struct clk *c);

+unsigned long clk_get_rate_all_locked(struct clk *c);
#endif
diff --git a/arch/arm/mach-tegra/tegra2_clocks.c b/arch/arm/mach-tegra/tegra2_clocks.c
index f03c712..ab013b1 100644
--- a/arch/arm/mach-tegra/tegra2_clocks.c
+++ b/arch/arm/mach-tegra/tegra2_clocks.c
@@ -23,8 +23,8 @@
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/io.h>
-#include <linux/hrtimer.h>
#include <linux/clkdev.h>
+#include <linux/clk.h>

#include <mach/iomap.h>
#include <mach/suspend.h>
@@ -147,6 +147,13 @@
static void __iomem *reg_clk_base = IO_ADDRESS(TEGRA_CLK_RESET_BASE);
static void __iomem *reg_pmc_base = IO_ADDRESS(TEGRA_PMC_BASE);

+/*
+ * Some clocks share a register with other clocks. Any clock op that
+ * non-atomically modifies a register used by another clock must lock
+ * clock_register_lock first.
+ */
+static DEFINE_SPINLOCK(clock_register_lock);
+
#define clk_writel(value, reg) \
__raw_writel(value, (u32)reg_clk_base + (reg))
#define clk_readl(reg) \
@@ -330,12 +337,12 @@ static int tegra2_super_clk_set_parent(struct clk *c, struct clk *p)
val |= sel->value << shift;

if (c->refcnt)
- clk_enable_locked(p);
+ clk_enable(p);

clk_writel(val, c->reg);

if (c->refcnt && c->parent)
- clk_disable_locked(c->parent);
+ clk_disable(c->parent);

clk_reparent(c, p);
return 0;
@@ -378,22 +385,22 @@ static void tegra2_cpu_clk_disable(struct clk *c)
static int tegra2_cpu_clk_set_rate(struct clk *c, unsigned long rate)
{
int ret;
- ret = clk_set_parent_locked(c->parent, c->u.cpu.backup);
+ ret = clk_set_parent(c->parent, c->u.cpu.backup);
if (ret) {
pr_err("Failed to switch cpu to clock %s\n", c->u.cpu.backup->name);
return ret;
}

- if (rate == c->u.cpu.backup->rate)
+ if (rate == clk_get_rate(c->u.cpu.backup))
goto out;

- ret = clk_set_rate_locked(c->u.cpu.main, rate);
+ ret = clk_set_rate(c->u.cpu.main, rate);
if (ret) {
pr_err("Failed to change cpu pll to %lu\n", rate);
return ret;
}

- ret = clk_set_parent_locked(c->parent, c->u.cpu.main);
+ ret = clk_set_parent(c->parent, c->u.cpu.main);
if (ret) {
pr_err("Failed to switch cpu to clock %s\n", c->u.cpu.main->name);
return ret;
@@ -421,24 +428,45 @@ static void tegra2_bus_clk_init(struct clk *c)

static int tegra2_bus_clk_enable(struct clk *c)
{
- u32 val = clk_readl(c->reg);
+ u32 val;
+ unsigned long flags;
+
+ spin_lock_irqsave(&clock_register_lock, flags);
+
+ val = clk_readl(c->reg);
val &= ~(BUS_CLK_DISABLE << c->reg_shift);
clk_writel(val, c->reg);
+
+ spin_unlock_irqrestore(&clock_register_lock, flags);
+
return 0;
}

static void tegra2_bus_clk_disable(struct clk *c)
{
- u32 val = clk_readl(c->reg);
+ u32 val;
+ unsigned long flags;
+
+ spin_lock_irqsave(&clock_register_lock, flags);
+
+ val = clk_readl(c->reg);
val |= BUS_CLK_DISABLE << c->reg_shift;
clk_writel(val, c->reg);
+
+ spin_unlock_irqrestore(&clock_register_lock, flags);
}

static int tegra2_bus_clk_set_rate(struct clk *c, unsigned long rate)
{
- u32 val = clk_readl(c->reg);
- unsigned long parent_rate = c->parent->rate;
+ u32 val;
+ unsigned long parent_rate = clk_get_rate(c->parent);
+ unsigned long flags;
+ int ret = -EINVAL;
int i;
+
+ spin_lock_irqsave(&clock_register_lock, flags);
+
+ val = clk_readl(c->reg);
for (i = 1; i <= 4; i++) {
if (rate == parent_rate / i) {
val &= ~(BUS_CLK_DIV_MASK << c->reg_shift);
@@ -446,10 +474,14 @@ static int tegra2_bus_clk_set_rate(struct clk *c, unsigned long rate)
clk_writel(val, c->reg);
c->div = i;
c->mul = 1;
- return 0;
+ ret = 0;
+ break;
}
}
- return -EINVAL;
+
+ spin_unlock_irqrestore(&clock_register_lock, flags);
+
+ return ret;
}

static struct clk_ops tegra_bus_ops = {
@@ -511,14 +543,15 @@ static void tegra2_blink_clk_disable(struct clk *c)

static int tegra2_blink_clk_set_rate(struct clk *c, unsigned long rate)
{
- if (rate >= c->parent->rate) {
+ unsigned long parent_rate = clk_get_rate(c->parent);
+ if (rate >= parent_rate) {
c->div = 1;
pmc_writel(0, c->reg);
} else {
unsigned int on_off;
u32 val;

- on_off = DIV_ROUND_UP(c->parent->rate / 8, rate);
+ on_off = DIV_ROUND_UP(parent_rate / 8, rate);
c->div = on_off * 8;

val = (on_off & PMC_BLINK_TIMER_DATA_ON_MASK) <<
@@ -604,7 +637,7 @@ static int tegra2_pll_clk_set_rate(struct clk *c, unsigned long rate)

pr_debug("%s: %s %lu\n", __func__, c->name, rate);

- input_rate = c->parent->rate;
+ input_rate = clk_get_rate(c->parent);
for (sel = c->u.pll.freq_table; sel->input_rate != 0; sel++) {
if (sel->input_rate == input_rate && sel->output_rate == rate) {
c->mul = sel->n;
@@ -717,9 +750,11 @@ static int tegra2_pll_div_clk_enable(struct clk *c)
{
u32 val;
u32 new_val;
+ unsigned long flags;

pr_debug("%s: %s\n", __func__, c->name);
if (c->flags & DIV_U71) {
+ spin_lock_irqsave(&clock_register_lock, flags);
val = clk_readl(c->reg);
new_val = val >> c->reg_shift;
new_val &= 0xFFFF;
@@ -729,12 +764,15 @@ static int tegra2_pll_div_clk_enable(struct clk *c)
val &= ~(0xFFFF << c->reg_shift);
val |= new_val << c->reg_shift;
clk_writel(val, c->reg);
+ spin_unlock_irqrestore(&clock_register_lock, flags);
return 0;
} else if (c->flags & DIV_2) {
BUG_ON(!(c->flags & PLLD));
+ spin_lock_irqsave(&clock_register_lock, flags);
val = clk_readl(c->reg);
val &= ~PLLD_MISC_DIV_RST;
clk_writel(val, c->reg);
+ spin_unlock_irqrestore(&clock_register_lock, flags);
return 0;
}
return -EINVAL;
@@ -744,9 +782,11 @@ static void tegra2_pll_div_clk_disable(struct clk *c)
{
u32 val;
u32 new_val;
+ unsigned long flags;

pr_debug("%s: %s\n", __func__, c->name);
if (c->flags & DIV_U71) {
+ spin_lock_irqsave(&clock_register_lock, flags);
val = clk_readl(c->reg);
new_val = val >> c->reg_shift;
new_val &= 0xFFFF;
@@ -756,11 +796,14 @@ static void tegra2_pll_div_clk_disable(struct clk *c)
val &= ~(0xFFFF << c->reg_shift);
val |= new_val << c->reg_shift;
clk_writel(val, c->reg);
+ spin_unlock_irqrestore(&clock_register_lock, flags);
} else if (c->flags & DIV_2) {
BUG_ON(!(c->flags & PLLD));
+ spin_lock_irqsave(&clock_register_lock, flags);
val = clk_readl(c->reg);
val |= PLLD_MISC_DIV_RST;
clk_writel(val, c->reg);
+ spin_unlock_irqrestore(&clock_register_lock, flags);
}
}

@@ -769,10 +812,14 @@ static int tegra2_pll_div_clk_set_rate(struct clk *c, unsigned long rate)
u32 val;
u32 new_val;
int divider_u71;
+ unsigned long parent_rate = clk_get_rate(c->parent);
+ unsigned long flags;
+
pr_debug("%s: %s %lu\n", __func__, c->name, rate);
if (c->flags & DIV_U71) {
- divider_u71 = clk_div71_get_divider(c->parent->rate, rate);
+ divider_u71 = clk_div71_get_divider(parent_rate, rate);
if (divider_u71 >= 0) {
+ spin_lock_irqsave(&clock_register_lock, flags);
val = clk_readl(c->reg);
new_val = val >> c->reg_shift;
new_val &= 0xFFFF;
@@ -786,10 +833,11 @@ static int tegra2_pll_div_clk_set_rate(struct clk *c, unsigned long rate)
clk_writel(val, c->reg);
c->div = divider_u71 + 2;
c->mul = 2;
+ spin_unlock_irqrestore(&clock_register_lock, flags);
return 0;
}
} else if (c->flags & DIV_2) {
- if (c->parent->rate == rate * 2)
+ if (parent_rate == rate * 2)
return 0;
}
return -EINVAL;
@@ -798,15 +846,16 @@ static int tegra2_pll_div_clk_set_rate(struct clk *c, unsigned long rate)
static long tegra2_pll_div_clk_round_rate(struct clk *c, unsigned long rate)
{
int divider;
+ unsigned long parent_rate = clk_get_rate(c->parent);
pr_debug("%s: %s %lu\n", __func__, c->name, rate);

if (c->flags & DIV_U71) {
- divider = clk_div71_get_divider(c->parent->rate, rate);
+ divider = clk_div71_get_divider(parent_rate, rate);
if (divider < 0)
return divider;
- return c->parent->rate * 2 / (divider + 2);
+ return parent_rate * 2 / (divider + 2);
} else if (c->flags & DIV_2) {
- return c->parent->rate / 2;
+ return parent_rate / 2;
}
return -EINVAL;
}
@@ -912,12 +961,12 @@ static int tegra2_periph_clk_set_parent(struct clk *c, struct clk *p)
val |= (sel->value) << PERIPH_CLK_SOURCE_SHIFT;

if (c->refcnt)
- clk_enable_locked(p);
+ clk_enable(p);

clk_writel(val, c->reg);

if (c->refcnt && c->parent)
- clk_disable_locked(c->parent);
+ clk_disable(c->parent);

clk_reparent(c, p);
return 0;
@@ -931,9 +980,10 @@ static int tegra2_periph_clk_set_rate(struct clk *c, unsigned long rate)
{
u32 val;
int divider;
- pr_debug("%s: %lu\n", __func__, rate);
+ unsigned long parent_rate = clk_get_rate(c->parent);
+
if (c->flags & DIV_U71) {
- divider = clk_div71_get_divider(c->parent->rate, rate);
+ divider = clk_div71_get_divider(parent_rate, rate);
if (divider >= 0) {
val = clk_readl(c->reg);
val &= ~PERIPH_CLK_SOURCE_DIVU71_MASK;
@@ -944,7 +994,7 @@ static int tegra2_periph_clk_set_rate(struct clk *c, unsigned long rate)
return 0;
}
} else if (c->flags & DIV_U16) {
- divider = clk_div16_get_divider(c->parent->rate, rate);
+ divider = clk_div16_get_divider(parent_rate, rate);
if (divider >= 0) {
val = clk_readl(c->reg);
val &= ~PERIPH_CLK_SOURCE_DIVU16_MASK;
@@ -954,7 +1004,7 @@ static int tegra2_periph_clk_set_rate(struct clk *c, unsigned long rate)
c->mul = 1;
return 0;
}
- } else if (c->parent->rate <= rate) {
+ } else if (parent_rate <= rate) {
c->div = 1;
c->mul = 1;
return 0;
@@ -966,19 +1016,20 @@ static long tegra2_periph_clk_round_rate(struct clk *c,
unsigned long rate)
{
int divider;
+ unsigned long parent_rate = clk_get_rate(c->parent);
pr_debug("%s: %s %lu\n", __func__, c->name, rate);

if (c->flags & DIV_U71) {
- divider = clk_div71_get_divider(c->parent->rate, rate);
+ divider = clk_div71_get_divider(parent_rate, rate);
if (divider < 0)
return divider;

- return c->parent->rate * 2 / (divider + 2);
+ return parent_rate * 2 / (divider + 2);
} else if (c->flags & DIV_U16) {
- divider = clk_div16_get_divider(c->parent->rate, rate);
+ divider = clk_div16_get_divider(parent_rate, rate);
if (divider < 0)
return divider;
- return c->parent->rate / (divider + 1);
+ return parent_rate / (divider + 1);
}
return -EINVAL;
}
@@ -1006,7 +1057,7 @@ static void tegra2_clk_double_init(struct clk *c)

static int tegra2_clk_double_set_rate(struct clk *c, unsigned long rate)
{
- if (rate != 2 * c->parent->rate)
+ if (rate != 2 * clk_get_rate(c->parent))
return -EINVAL;
c->mul = 2;
c->div = 1;
@@ -1057,12 +1108,12 @@ static int tegra2_audio_sync_clk_set_parent(struct clk *c, struct clk *p)
val |= sel->value;

if (c->refcnt)
- clk_enable_locked(p);
+ clk_enable(p);

clk_writel(val, c->reg);

if (c->refcnt && c->parent)
- clk_disable_locked(c->parent);
+ clk_disable(c->parent);

clk_reparent(c, p);
return 0;
--
1.7.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

Next message: Colin Cross: "[PATCH v2 09/21] ARM: tegra: clock: Move unshared clk struct members into union"
Previous message: Colin Cross: "[PATCH v2 12/21] ARM: tegra: clock: Add shared bus clock type"
In reply to: Colin Cross: "[PATCH v2 12/21] ARM: tegra: clock: Add shared bus clock type"
Next in thread: Olof Johansson: "Re: [PATCH v2 10/21] ARM: tegra: clock: Convert global lock to a lockper clock"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]