Commit 46c12216 authored by Russell King's avatar Russell King Committed by Kevin Hilman
Browse files

cpufreq: OMAP: Add SMP support for OMAP4+ 



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: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
[khilman@ti.com: due to overlap/rework, combined original Santosh patch
                 and Russell's rework]
Signed-off-by: default avatarKevin Hilman <khilman@ti.com>
parent 731e0cc6

drivers/cpufreq/omap-cpufreq.c

+71 −10
Original line number Diff line number Diff line
@@ -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;

CRA Git | Maintained and supported by SUSTech CRA and CCSE