[POWERPC] cell: use pmi in cpufreq driver

The new PMI driver was added in order to support
cpufreq on blades that require the frequency to
be controlled by the service processor, so use it
on those.
Signed-off-by: Christian Krafft <krafft@de.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

arch/powerpc/platforms/cell/cbe_cpufreq.c

@@ -28,6 +28,8 @@
 #include <asm/processor.h>
 #include <asm/prom.h>
 #include <asm/time.h>
+#include <asm/pmi.h>
+#include <asm/of_platform.h>
 
 #include "cbe_regs.h"
 
@@ -68,6 +70,38 @@ static u64 MIC_Slow_Next_Timer_table[] = {
  * hardware specific functions
  */
 
+static struct of_device *pmi_dev;
+
+static int set_pmode_pmi(int cpu, unsigned int pmode)
+{
+	int ret;
+	pmi_message_t pmi_msg;
+#ifdef DEBUG
+	u64 time;
+#endif
+
+	pmi_msg.type = PMI_TYPE_FREQ_CHANGE;
+	pmi_msg.data1 =	cbe_cpu_to_node(cpu);
+	pmi_msg.data2 = pmode;
+
+#ifdef DEBUG
+	time = (u64) get_cycles();
+#endif
+
+	pmi_send_message(pmi_dev, pmi_msg);
+	ret = pmi_msg.data2;
+
+	pr_debug("PMI returned slow mode %d\n", ret);
+
+#ifdef DEBUG
+	time = (u64) get_cycles() - time; /* actual cycles (not cpu cycles!) */
+	time = 1000000000 * time / CLOCK_TICK_RATE; /* time in ns (10^-9) */
+	pr_debug("had to wait %lu ns for a transition\n", time);
+#endif
+	return ret;
+}
+
+
 static int get_pmode(int cpu)
 {
 	int ret;
@@ -79,7 +113,7 @@ static int get_pmode(int cpu)
 	return ret;
 }
 
-static int set_pmode(int cpu, unsigned int pmode)
+static int set_pmode_reg(int cpu, unsigned int pmode)
 {
 	struct cbe_pmd_regs __iomem *pmd_regs;
 	struct cbe_mic_tm_regs __iomem *mic_tm_regs;
@@ -120,6 +154,39 @@ static int set_pmode(int cpu, unsigned int pmode)
 	return 0;
 }
 
+static int set_pmode(int cpu, unsigned int slow_mode) {
+	if(pmi_dev)
+		return set_pmode_pmi(cpu, slow_mode);
+	else
+		return set_pmode_reg(cpu, slow_mode);
+}
+
+static void cbe_cpufreq_handle_pmi(struct of_device *dev, pmi_message_t pmi_msg)
+{
+	struct cpufreq_policy policy;
+	u8 cpu;
+	u8 cbe_pmode_new;
+
+	BUG_ON (pmi_msg.type != PMI_TYPE_FREQ_CHANGE);
+
+	cpu = cbe_node_to_cpu(pmi_msg.data1);
+	cbe_pmode_new = pmi_msg.data2;
+
+	cpufreq_get_policy(&policy, cpu);
+
+	policy.max = min(policy.max, cbe_freqs[cbe_pmode_new].frequency);
+	policy.min = min(policy.min, policy.max);
+
+	pr_debug("cbe_handle_pmi: new policy.min=%d policy.max=%d\n", policy.min, policy.max);
+	cpufreq_set_policy(&policy);
+}
+
+static struct pmi_handler cbe_pmi_handler = {
+	.type			= PMI_TYPE_FREQ_CHANGE,
+	.handle_pmi_message	= cbe_cpufreq_handle_pmi,
+};
+
+
 /*
  * cpufreq functions
  */
@@ -234,11 +301,23 @@ static struct cpufreq_driver cbe_cpufreq_driver = {
 
 static int __init cbe_cpufreq_init(void)
 {
+	struct device_node *np;
+
+	np = of_find_node_by_type(NULL, "ibm,pmi");
+
+	pmi_dev = of_find_device_by_node(np);
+
+	if (pmi_dev)
+		pmi_register_handler(pmi_dev, &cbe_pmi_handler);
+
 	return cpufreq_register_driver(&cbe_cpufreq_driver);
 }
 
 static void __exit cbe_cpufreq_exit(void)
 {
+	if(pmi_dev)
+		pmi_unregister_handler(pmi_dev, &cbe_pmi_handler);
+
 	cpufreq_unregister_driver(&cbe_cpufreq_driver);
 }