Blackfin: SMP: implement cpu_freq support

Re-use some of the existing cpu hotplugging code in the process.

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

2 files changed, 48 insertions, 4 deletions

diff --git a/arch/blackfin/mach-common/cpufreq.c b/arch/blackfin/mach-common/cpufreq.c
index f4cf11d..c33fb61 100644
--- a/arch/blackfin/mach-common/cpufreq.c
+++ b/arch/blackfin/mach-common/cpufreq.c
@@ -16,8 +16,6 @@
 #include <asm/time.h>
 #include <asm/dpmc.h>
 
-#define CPUFREQ_CPU 0
-
 /* this is the table of CCLK frequencies, in Hz */
 /* .index is the entry in the auxillary dpm_state_table[] */
 static struct cpufreq_frequency_table bfin_freq_table[] = {
diff --git a/arch/blackfin/mach-common/dpmc.c b/arch/blackfin/mach-common/dpmc.c
index 02c7efd..382099f 100644
--- a/arch/blackfin/mach-common/dpmc.c
+++ b/arch/blackfin/mach-common/dpmc.c
@@ -61,17 +61,63 @@ err_out:
 }
 
 #ifdef CONFIG_CPU_FREQ
+# ifdef CONFIG_SMP
+static void bfin_idle_this_cpu(void *info)
+{
+	unsigned long flags = 0;
+	unsigned long iwr0, iwr1, iwr2;
+	unsigned int cpu = smp_processor_id();
+
+	local_irq_save_hw(flags);
+	bfin_iwr_set_sup0(&iwr0, &iwr1, &iwr2);
+
+	platform_clear_ipi(cpu, IRQ_SUPPLE_0);
+	SSYNC();
+	asm("IDLE;");
+	bfin_iwr_restore(iwr0, iwr1, iwr2);
+
+	local_irq_restore_hw(flags);
+}
+
+static void bfin_idle_cpu(void)
+{
+	smp_call_function(bfin_idle_this_cpu, NULL, 0);
+}
+
+static void bfin_wakeup_cpu(void)
+{
+	unsigned int cpu;
+	unsigned int this_cpu = smp_processor_id();
+	cpumask_t mask = cpu_online_map;
+
+	cpu_clear(this_cpu, mask);
+	for_each_cpu_mask(cpu, mask)
+		platform_send_ipi_cpu(cpu, IRQ_SUPPLE_0);
+}
+
+# else
+static void bfin_idle_cpu(void) {}
+static void bfin_wakeup_cpu(void) {}
+# endif
+
 static int
 vreg_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
 {
 	struct cpufreq_freqs *freq = data;
 
+	if (freq->cpu != CPUFREQ_CPU)
+		return 0;
+
 	if (val == CPUFREQ_PRECHANGE && freq->old < freq->new) {
+		bfin_idle_cpu();
 		bfin_set_vlev(bfin_get_vlev(freq->new));
 		udelay(pdata->vr_settling_time); /* Wait until Volatge settled */
-
-	} else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)
+		bfin_wakeup_cpu();
+	} else if (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) {
+		bfin_idle_cpu();
 		bfin_set_vlev(bfin_get_vlev(freq->new));
+		bfin_wakeup_cpu();
+	}
 
 	return 0;
 }