[CPUFREQ] Move PMBASE reading away and do it only once at initialization time

This patch moves away PMBASE reading and only performs it at
cpufreq_register_driver time by exiting with -ENODEV if unable to read
the value.

Signed-off-by: Mattia Dongili <malattia@linux.it>
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>

1 files changed, 30 insertions, 13 deletions

diff --git a/arch/i386/kernel/cpu/cpufreq/speedstep-ich.c b/arch/i386/kernel/cpu/cpufreq/speedstep-ich.c
index 862e0b5656b9..b425cd3d1838 100644
--- a/arch/i386/kernel/cpu/cpufreq/speedstep-ich.c
+++ b/arch/i386/kernel/cpu/cpufreq/speedstep-ich.c
@@ -40,6 +40,7 @@ static struct pci_dev *speedstep_chipset_dev;
  */
 static unsigned int speedstep_processor = 0;
 
+static u32 pmbase;
 
 /*
  *   There are only two frequency states for each processor. Values
@@ -56,34 +57,47 @@ static struct cpufreq_frequency_table speedstep_freqs[] = {
 
 
 /**
- * speedstep_set_state - set the SpeedStep state
- * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
+ * speedstep_find_register - read the PMBASE address
  *
- *   Tries to change the SpeedStep state.
+ * Returns: -ENODEV if no register could be found
  */
-static void speedstep_set_state (unsigned int state)
+static int speedstep_find_register (void)
 {
-        u32 pmbase;
-        u8 pm2_blk;
-        u8 value;
-        unsigned long flags;
-
-        if (!speedstep_chipset_dev || (state > 0x1))
-                return;
+        if (!speedstep_chipset_dev)
+                return -ENODEV;
 
         /* get PMBASE */
         pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
         if (!(pmbase & 0x01)) {
                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
-                return;
+                return -ENODEV;
         }
 
         pmbase &= 0xFFFFFFFE;
         if (!pmbase) {
                 printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
-                return;
+                return -ENODEV;
         }
 
+        dprintk("pmbase is 0x%x\n", pmbase);
+        return 0;
+}
+
+/**
+ * speedstep_set_state - set the SpeedStep state
+ * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
+ *
+ *   Tries to change the SpeedStep state.
+ */
+static void speedstep_set_state (unsigned int state)
+{
+        u8 pm2_blk;
+        u8 value;
+        unsigned long flags;
+
+        if (state > 0x1)
+                return;
+
         /* Disable IRQs */
         local_irq_save(flags);
 
@@ -400,6 +414,9 @@ static int __init speedstep_init(void)
                 return -EINVAL;
         }
 
+        if (speedstep_find_register())
+                return -ENODEV;
+
         return cpufreq_register_driver(&speedstep_driver);
 }