[POWERPC] Add cpufreq support for Xserve G5

The Xserve G5 are capable of frequency switching like other desktop G5s.
This enables it. It also fix a Kconfig issue which prevented from
building the G5 cpufreq support if CONFIG_PMAC_SMU was not set (the
first version of that driver only worked with SMU based macs, but this
isn't the case anymore).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 50 insertions, 30 deletions

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2643dbc3f289..13e583f16ede 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -504,7 +504,7 @@ config CPU_FREQ_PMAC
 
 config CPU_FREQ_PMAC64
         bool "Support for some Apple G5s"
-        depends on CPU_FREQ && PMAC_SMU && PPC64
+        depends on CPU_FREQ && PPC64
         select CPU_FREQ_TABLE
         help
           This adds support for frequency switching on Apple iMac G5,
diff --git a/arch/powerpc/platforms/powermac/cpufreq_64.c b/arch/powerpc/platforms/powermac/cpufreq_64.c
index f08a14516139..a6a84ac5433e 100644
--- a/arch/powerpc/platforms/powermac/cpufreq_64.c
+++ b/arch/powerpc/platforms/powermac/cpufreq_64.c
@@ -10,6 +10,8 @@
  * that is iMac G5 and latest single CPU desktop.
  */
 
+#undef DEBUG
+
 #include <linux/module.h>
 #include <linux/types.h>
 #include <linux/errno.h>
@@ -30,13 +32,7 @@
 #include <asm/smu.h>
 #include <asm/pmac_pfunc.h>
 
-#undef DEBUG
-
-#ifdef DEBUG
-#define DBG(fmt...) printk(fmt)
-#else
-#define DBG(fmt...)
-#endif
+#define DBG(fmt...) pr_debug(fmt)
 
 /* see 970FX user manual */
 
@@ -82,8 +78,6 @@ static struct freq_attr* g5_cpu_freqs_attr[] = {
 /* Power mode data is an array of the 32 bits PCR values to use for
  * the various frequencies, retrieved from the device-tree
  */
-static u32 *g5_pmode_data;
-static int g5_pmode_max;
 static int g5_pmode_cur;
 
 static void (*g5_switch_volt)(int speed_mode);
@@ -93,6 +87,11 @@ static int (*g5_query_freq)(void);
 static DEFINE_MUTEX(g5_switch_mutex);
 
 
+#ifdef CONFIG_PPC_SMU
+
+static u32 *g5_pmode_data;
+static int g5_pmode_max;
+
 static struct smu_sdbp_fvt *g5_fvt_table;       /* table of op. points */
 static int g5_fvt_count;                        /* number of op. points */
 static int g5_fvt_cur;                          /* current op. point */
@@ -210,6 +209,16 @@ static int g5_scom_query_freq(void)
 }
 
 /*
+ * Fake voltage switching for platforms with missing support
+ */
+
+static void g5_dummy_switch_volt(int speed_mode)
+{
+}
+
+#endif /* CONFIG_PPC_SMU */
+
+/*
  * Platform function based voltage switching for PowerMac7,2 & 7,3
  */
 
@@ -248,6 +257,9 @@ static int g5_pfunc_switch_freq(int speed_mode)
         struct pmf_args args;
         u32 done = 0;
         unsigned long timeout;
+        int rc;
+
+        DBG("g5_pfunc_switch_freq(%d)\n", speed_mode);
 
         /* If frequency is going up, first ramp up the voltage */
         if (speed_mode < g5_pmode_cur)
@@ -255,9 +267,12 @@ static int g5_pfunc_switch_freq(int speed_mode)
 
         /* Do it */
         if (speed_mode == CPUFREQ_HIGH)
-                pmf_call_one(pfunc_cpu_setfreq_high, NULL);
+                rc = pmf_call_one(pfunc_cpu_setfreq_high, NULL);
         else
-                pmf_call_one(pfunc_cpu_setfreq_low, NULL);
+                rc = pmf_call_one(pfunc_cpu_setfreq_low, NULL);
+
+        if (rc)
+                printk(KERN_WARNING "cpufreq: pfunc switch error %d\n", rc);
 
         /* It's an irq GPIO so we should be able to just block here,
          * I'll do that later after I've properly tested the IRQ code for
@@ -296,13 +311,6 @@ static int g5_pfunc_query_freq(void)
         return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
 }
 
-/*
- * Fake voltage switching for platforms with missing support
- */
-
-static void g5_dummy_switch_volt(int speed_mode)
-{
-}
 
 /*
  * Common interface to the cpufreq core
@@ -375,6 +383,8 @@ static struct cpufreq_driver g5_cpufreq_driver = {
 };
 
 
+#ifdef CONFIG_PPC_SMU
+
 static int __init g5_neo2_cpufreq_init(struct device_node *cpus)
 {
         struct device_node *cpunode;
@@ -525,6 +535,9 @@ static int __init g5_neo2_cpufreq_init(struct device_node *cpus)
         return rc;
 }
 
+#endif /* CONFIG_PPC_SMU */
+
+
 static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
 {
         struct device_node *cpuid = NULL, *hwclock = NULL, *cpunode = NULL;
@@ -533,6 +546,9 @@ static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
         u64 max_freq, min_freq, ih, il;
         int has_volt = 1, rc = 0;
 
+        DBG("cpufreq: Initializing for PowerMac7,2, PowerMac7,3 and"
+            " RackMac3,1...\n");
+
         /* Get first CPU node */
         for (cpunode = NULL;
              (cpunode = of_get_next_child(cpus, cpunode)) != NULL;) {
@@ -636,6 +652,15 @@ static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
          */
         ih = *((u32 *)(eeprom + 0x10));
         il = *((u32 *)(eeprom + 0x20));
+
+        /* Check for machines with no useful settings */
+        if (il == ih) {
+                printk(KERN_WARNING "cpufreq: No low frequency mode available"
+                       " on this model !\n");
+                rc = -ENODEV;
+                goto bail;
+        }
+
         min_freq = 0;
         if (ih != 0 && il != 0)
                 min_freq = (max_freq * il) / ih;
@@ -643,7 +668,7 @@ static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
         /* Sanity check */
         if (min_freq >= max_freq || min_freq < 1000) {
                 printk(KERN_ERR "cpufreq: Can't calculate low frequency !\n");
-                rc = -ENODEV;
+                rc = -ENXIO;
                 goto bail;
         }
         g5_cpu_freqs[0].frequency = max_freq;
@@ -690,16 +715,10 @@ static int __init g5_pm72_cpufreq_init(struct device_node *cpus)
         return rc;
 }
 
-static int __init g5_rm31_cpufreq_init(struct device_node *cpus)
-{
-        /* NYI */
-        return 0;
-}
-
 static int __init g5_cpufreq_init(void)
 {
         struct device_node *cpus;
-        int rc;
+        int rc = 0;
 
         cpus = of_find_node_by_path("/cpus");
         if (cpus == NULL) {
@@ -708,12 +727,13 @@ static int __init g5_cpufreq_init(void)
         }
 
         if (machine_is_compatible("PowerMac7,2") ||
-            machine_is_compatible("PowerMac7,3"))
+            machine_is_compatible("PowerMac7,3") ||
+            machine_is_compatible("RackMac3,1"))
                 rc = g5_pm72_cpufreq_init(cpus);
-        else if (machine_is_compatible("RackMac3,1"))
-                rc = g5_rm31_cpufreq_init(cpus);
+#ifdef CONFIG_PPC_SMU
         else
                 rc = g5_neo2_cpufreq_init(cpus);
+#endif /* CONFIG_PPC_SMU */
 
         of_node_put(cpus);
         return rc;