From: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
[khilman@xxxxxx: due to overlap/rework, combined original Santosh patch
and Russell's rework]
Signed-off-by: Kevin Hilman <khilman@xxxxxx>
---
drivers/cpufreq/omap-cpufreq.c | 80 +++++++++++++++++++++++++++++++++++-----
1 files changed, 70 insertions(+), 10 deletions(-)
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index a6b2be7..f9b4c4d 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -23,6 +23,7 @@
#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>
@@ -35,6 +36,16 @@
#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 +71,7 @@ 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 +82,7 @@ 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 +92,57 @@ 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;
- cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ /* 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);
+ }
- cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ /* 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 +151,7 @@ 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 +163,12 @@ 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 +188,20 @@ 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;
--
1.7.6
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