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cpufreq: OMAP: Add SMP support for OMAP4+

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On OMAP SMP configuartion, both processors share the voltage
and clock. So both CPUs needs to be scaled together and hence
needs software co-ordination.

Also, update lpj with reference value to avoid progressive error.

Adjust _both_ the per-cpu loops_per_jiffy and global lpj. Calibrate
them with with reference to the initial values to avoid a
progressively bigger and bigger error in the value over time.

While at this, re-use the notifiers for UP/SMP since on UP machine or
UP_ON_SMP policy->cpus mask would contain only the boot CPU.

Based on initial SMP support by Santosh Shilimkar.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
[khilman@ti.com: due to overlap/rework, combined original Santosh patch
                 and Russell's rework]
Signed-off-by: Kevin Hilman <khilman@ti.com>
This commit is contained in:
Russell King 2011-09-21 16:53:00 -07:00 committed by Kevin Hilman
parent 731e0cc639
commit 46c12216c8
1 changed files with 71 additions and 10 deletions
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77
drivers/cpufreq/omap-cpufreq.c
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@ -23,9 +23,11 @@
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/opp.h>
#include <linux/cpu.h>
#include <asm/system.h>
#include <asm/smp_plat.h>
#include <asm/cpu.h>
#include <plat/clock.h>
#include <plat/omap-pm.h>
@ -35,6 +37,16 @@
#define VERY_HI_RATE 900000000
#ifdef CONFIG_SMP
struct lpj_info {
unsigned long ref;
unsigned int freq;
};
static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
static struct lpj_info global_lpj_ref;
#endif
static struct cpufreq_frequency_table *freq_table;
static struct clk *mpu_clk;
@ -60,7 +72,7 @@ static unsigned int omap_getspeed(unsigned int cpu)
{
unsigned long rate;
if (cpu)
if (cpu >= NR_CPUS)
return 0;
rate = clk_get_rate(mpu_clk) / 1000;
@ -71,7 +83,7 @@ static int omap_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
int ret = 0;
int i, ret = 0;
struct cpufreq_freqs freqs;
/* Ensure desired rate is within allowed range. Some govenors
@ -81,22 +93,57 @@ static int omap_target(struct cpufreq_policy *policy,
if (target_freq > policy->max)
target_freq = policy->max;
freqs.old = omap_getspeed(0);
freqs.old = omap_getspeed(policy->cpu);
freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
freqs.cpu = 0;
freqs.cpu = policy->cpu;
if (freqs.old == freqs.new)
return ret;
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
#ifdef CONFIG_CPU_FREQ_DEBUG
pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
#endif
ret = clk_set_rate(mpu_clk, freqs.new * 1000);
freqs.new = omap_getspeed(policy->cpu);
#ifdef CONFIG_SMP
/*
* Note that loops_per_jiffy is not updated on SMP systems in
* cpufreq driver. So, update the per-CPU loops_per_jiffy value
* on frequency transition. We need to update all dependent CPUs.
*/
for_each_cpu(i, policy->cpus) {
struct lpj_info *lpj = &per_cpu(lpj_ref, i);
if (!lpj->freq) {
lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
lpj->freq = freqs.old;
}
per_cpu(cpu_data, i).loops_per_jiffy =
cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
}
/* And don't forget to adjust the global one */
if (!global_lpj_ref.freq) {
global_lpj_ref.ref = loops_per_jiffy;
global_lpj_ref.freq = freqs.old;
}
loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
freqs.new);
#endif
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
return ret;
}
@ -105,6 +152,7 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
{
int result = 0;
struct device *mpu_dev;
static cpumask_var_t cpumask;
if (cpu_is_omap24xx())
mpu_clk = clk_get(NULL, "virt_prcm_set");
@ -116,12 +164,12 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
if (IS_ERR(mpu_clk))
return PTR_ERR(mpu_clk);
if (policy->cpu != 0)
if (policy->cpu >= NR_CPUS)
return -EINVAL;
policy->cur = policy->min = policy->max = omap_getspeed(0);
policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
mpu_dev = omap2_get_mpuss_device();
if (!mpu_dev) {
pr_warning("%s: unable to get the mpu device\n", __func__);
return -EINVAL;
@ -141,7 +189,20 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = omap_getspeed(0);
policy->cur = omap_getspeed(policy->cpu);
/*
* On OMAP SMP configuartion, both processors share the voltage
* and clock. So both CPUs needs to be scaled together and hence
* needs software co-ordination. Use cpufreq affected_cpus
* interface to handle this scenario. Additional is_smp() check
* is to keep SMP_ON_UP build working.
*/
if (is_smp()) {
policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
cpumask_or(cpumask, cpumask_of(policy->cpu), cpumask);
cpumask_copy(policy->cpus, cpumask);
}
/* FIXME: what's the actual transition time? */
policy->cpuinfo.transition_latency = 300 * 1000;