> -----Original Message-----
> From: linux-omap-ow...@vger.kernel.org [mailto:linux-omap-
> ow...@vger.kernel.org] On Behalf Of Shilimkar, Santosh
> Sent: Friday, February 25, 2011 11:41 AM
> To: linux-omap@vger.kernel.org
> Cc: Hilman, Kevin; Sripathy, Vishwanath; Shilimkar, Santosh
> Subject: [PATCH 3/3] omap2plus: cpufreq: Add SMP support to cater OMAP4430
>
> 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.
>
> Signed-off-by: Santosh Shilimkar <santosh.shilim...@ti.com>
> Cc: Kevin Hilman <khil...@ti.com>
> cc: Vishwanath BS <vishwanath...@ti.com>
> ---
> arch/arm/mach-omap2/omap2plus-cpufreq.c | 71
> ++++++++++++++++++++++++++----
> 1 files changed, 61 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/omap2plus-cpufreq.c b/arch/arm/mach-
> omap2/omap2plus-cpufreq.c
> index 48da867..8c903c1 100644
> --- a/arch/arm/mach-omap2/omap2plus-cpufreq.c
> +++ b/arch/arm/mach-omap2/omap2plus-cpufreq.c
> @@ -26,9 +26,11 @@
> #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>
> @@ -63,7 +65,7 @@ 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;
> @@ -74,9 +76,13 @@ 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;
>
> + /* Wait untill all CPU's are initialized */
Typo: until
> + if (is_smp() && (num_online_cpus() < NR_CPUS))
> + return ret;
Does it make sense to add pr_info() or pr_warning() before returning?
> +
> /* Ensure desired rate is within allowed range. Some govenors
> * (ondemand) will just pass target_freq=0 to get the minimum. */
> if (target_freq < policy->min)
> @@ -84,15 +90,25 @@ 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);
> + if (!is_smp()) {
> + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> + goto set_freq;
> + }
> +
> + /* notifiers */
> + for_each_cpu(i, policy->cpus) {
> + freqs.cpu = i;
> + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> + }
>
> +set_freq:
> #ifdef CONFIG_CPU_FREQ_DEBUG
> pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old,
> freqs.new);
> #endif
> @@ -100,6 +116,7 @@ static int omap_target(struct cpufreq_policy *policy,
> ret = clk_set_rate(mpu_clk, freqs.new * 1000);
> if (ret)
> return ret;
> + freqs.new = omap_getspeed(policy->cpu);
>
> /*
> * Generic CPUFREQ driver jiffy update is under !SMP. So jiffies
> @@ -107,12 +124,32 @@ static int omap_target(struct cpufreq_policy
> *policy,
> * CONFIG_SMP enabled. Below code is added only to manage that
> * scenario
> */
> - if (!is_smp())
> + if (!is_smp()) {
> loops_per_jiffy =
> cpufreq_scale(loops_per_jiffy, freqs.old, freqs.new);
> + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> + goto skip_lpj;
> + }
>
> - cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +#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
CPUs.
> + */
> + for_each_cpu(i, policy->cpus)
> + per_cpu(cpu_data, i).loops_per_jiffy =
> + cpufreq_scale(per_cpu(cpu_data, i).loops_per_jiffy,
> + freqs.old, freqs.new);
> +#endif
> +
> + /* notifiers */
> + for_each_cpu(i, policy->cpus) {
> + freqs.cpu = i;
> + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> + }
>
> +skip_lpj:
> return ret;
> }
>
> @@ -120,15 +157,16 @@ static int __init omap_cpu_init(struct
> cpufreq_policy *policy)
> {
> int result = 0;
> struct device *mpu_dev;
> + static cpumask_var_t cpumask;
>
> mpu_clk = clk_get(NULL, "cpu_ck");
> 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) {
> @@ -150,7 +188,20 @@ static int __init 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 builf working.
Typo: build
> + */
> + 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;
> --
> 1.6.0.4
>
> --
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