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Subject[PATCH A 10/10] OMAP2: Implement CPUfreq frequency table based on PRCM table
Date
From: Kevin Hilman <khilman@mvista.com>

This patch adds a CPUfreq frequency-table implementation for OMAP2 by
walking the PRCM rate-table for available entries and adding them to a
CPUfreq table.

CPUfreq can then be used to manage switching between all the available
entries in the PRCM rate table. Either use the CPUfreq sysfs
interface directly, (see Section 3 of Documentation/cpu-freq/user-guide.txt)
or use the cpufrequtils package:
http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufrequtils.html

Signed-off-by: Kevin Hilman <khilman@mvista.com>

Updated to try to use cpufreq_table if it exists.

linux-omap source commit is 77ce544fa48deb7a2003f454624e3ca10d37ab87.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
---
arch/arm/mach-omap2/clock24xx.c | 42 +++++++++++++++++++++++
arch/arm/plat-omap/cpu-omap.c | 57 +++++++++++++++++++++++++++++--
arch/arm/plat-omap/include/mach/clock.h | 3 ++
3 files changed, 98 insertions(+), 4 deletions(-)
diff --git a/arch/arm/mach-omap2/clock24xx.c b/arch/arm/mach-omap2/clock24xx.c
index 133c36f..9240e64 100644
--- a/arch/arm/mach-omap2/clock24xx.c
+++ b/arch/arm/mach-omap2/clock24xx.c
@@ -378,6 +378,45 @@ static int omap2_select_table_rate(struct clk *clk, unsigned long rate)
return 0;
}

+#ifdef CONFIG_CPU_FREQ
+/*
+ * Walk PRCM rate table and fillout cpufreq freq_table
+ */
+static struct cpufreq_frequency_table freq_table[ARRAY_SIZE(rate_table)];
+
+void omap2_clk_init_cpufreq_table(struct cpufreq_frequency_table **table)
+{
+ struct prcm_config *prcm;
+ int i = 0;
+
+ for (prcm = rate_table; prcm->mpu_speed; prcm++) {
+ if (!(prcm->flags & cpu_mask))
+ continue;
+ if (prcm->xtal_speed != sys_ck.rate)
+ continue;
+
+ /* don't put bypass rates in table */
+ if (prcm->dpll_speed == prcm->xtal_speed)
+ continue;
+
+ freq_table[i].index = i;
+ freq_table[i].frequency = prcm->mpu_speed / 1000;
+ i++;
+ }
+
+ if (i == 0) {
+ printk(KERN_WARNING "%s: failed to initialize frequency "
+ "table\n", __func__);
+ return;
+ }
+
+ freq_table[i].index = i;
+ freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+ *table = &freq_table[0];
+}
+#endif
+
static struct clk_functions omap2_clk_functions = {
.clk_enable = omap2_clk_enable,
.clk_disable = omap2_clk_disable,
@@ -385,6 +424,9 @@ static struct clk_functions omap2_clk_functions = {
.clk_set_rate = omap2_clk_set_rate,
.clk_set_parent = omap2_clk_set_parent,
.clk_disable_unused = omap2_clk_disable_unused,
+#ifdef CONFIG_CPU_FREQ
+ .clk_init_cpufreq_table = omap2_clk_init_cpufreq_table,
+#endif
};

static u32 omap2_get_apll_clkin(void)
diff --git a/arch/arm/plat-omap/cpu-omap.c b/arch/arm/plat-omap/cpu-omap.c
index b269024..843e8af 100644
--- a/arch/arm/plat-omap/cpu-omap.c
+++ b/arch/arm/plat-omap/cpu-omap.c
@@ -23,10 +23,13 @@
#include <linux/io.h>

#include <mach/hardware.h>
+#include <mach/clock.h>
#include <asm/system.h>

#define VERY_HI_RATE 900000000

+static struct cpufreq_frequency_table *freq_table;
+
#ifdef CONFIG_ARCH_OMAP1
#define MPU_CLK "mpu"
#else
@@ -39,6 +42,9 @@ static struct clk *mpu_clk;

int omap_verify_speed(struct cpufreq_policy *policy)
{
+ if (freq_table)
+ return cpufreq_frequency_table_verify(policy, freq_table);
+
if (policy->cpu)
return -EINVAL;

@@ -70,12 +76,26 @@ static int omap_target(struct cpufreq_policy *policy,
struct cpufreq_freqs freqs;
int ret = 0;

+ /* Ensure desired rate is within allowed range. Some govenors
+ * (ondemand) will just pass target_freq=0 to get the minimum. */
+ if (target_freq < policy->cpuinfo.min_freq)
+ target_freq = policy->cpuinfo.min_freq;
+ if (target_freq > policy->cpuinfo.max_freq)
+ target_freq = policy->cpuinfo.max_freq;
+
freqs.old = omap_getspeed(0);
freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
freqs.cpu = 0;

+ if (freqs.old == freqs.new)
+ return ret;
+
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
- ret = clk_set_rate(mpu_clk, target_freq * 1000);
+#ifdef CONFIG_CPU_FREQ_DEBUG
+ printk(KERN_DEBUG "cpufreq-omap: transition: %u --> %u\n",
+ freqs.old, freqs.new);
+#endif
+ ret = clk_set_rate(mpu_clk, freqs.new * 1000);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

return ret;
@@ -83,16 +103,31 @@ static int omap_target(struct cpufreq_policy *policy,

static int __init omap_cpu_init(struct cpufreq_policy *policy)
{
+ int result = 0;
+
mpu_clk = clk_get(NULL, MPU_CLK);
if (IS_ERR(mpu_clk))
return PTR_ERR(mpu_clk);

if (policy->cpu != 0)
return -EINVAL;
+
policy->cur = policy->min = policy->max = omap_getspeed(0);
- policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
- policy->cpuinfo.max_freq = clk_round_rate(mpu_clk, VERY_HI_RATE) / 1000;
- policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+
+ clk_init_cpufreq_table(&freq_table);
+ if (freq_table) {
+ result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
+ if (!result)
+ cpufreq_frequency_table_get_attr(freq_table,
+ policy->cpu);
+ } else {
+ policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
+ policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
+ VERY_HI_RATE) / 1000;
+ }
+
+ /* FIXME: what's the actual transition time? */
+ policy->cpuinfo.transition_latency = 10 * 1000 * 1000;

return 0;
}
@@ -103,6 +138,11 @@ static int omap_cpu_exit(struct cpufreq_policy *policy)
return 0;
}

+static struct freq_attr *omap_cpufreq_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
static struct cpufreq_driver omap_driver = {
.flags = CPUFREQ_STICKY,
.verify = omap_verify_speed,
@@ -111,6 +151,7 @@ static struct cpufreq_driver omap_driver = {
.init = omap_cpu_init,
.exit = omap_cpu_exit,
.name = "omap",
+ .attr = omap_cpufreq_attr,
};

static int __init omap_cpufreq_init(void)
@@ -119,3 +160,11 @@ static int __init omap_cpufreq_init(void)
}

arch_initcall(omap_cpufreq_init);
+
+/*
+ * if ever we want to remove this, upon cleanup call:
+ *
+ * cpufreq_unregister_driver()
+ * cpufreq_frequency_table_put_attr()
+ */
+
diff --git a/arch/arm/plat-omap/include/mach/clock.h b/arch/arm/plat-omap/include/mach/clock.h
index e32937b..d78d3a7 100644
--- a/arch/arm/plat-omap/include/mach/clock.h
+++ b/arch/arm/plat-omap/include/mach/clock.h
@@ -121,6 +121,9 @@ 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);
+#ifdef CONFIG_CPU_FREQ
+extern void clk_init_cpufreq_table(struct cpufreq_frequency_table **table);
+#endif

/* Clock flags */
#define RATE_CKCTL (1 << 0) /* Main fixed ratio clocks */



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