x86, mrst: add more timer config options

Always-on local APIC timer (ARAT) has been introduced to Medfield, along
with the platform APB timers we have more timer configuration options
between Moorestown and Medfield.

This patch adds run-time detection of avaiable timer features so that
we can treat Medfield as a variant of Moorestown and set up the optimal
timer options for each platform. i.e.

Medfield: per cpu always-on local APIC timer
Moorestown: per cpu APB timer

Manual override is possible via cmdline option x86_mrst_timer.

Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
LKML-Reference: <1274295685-6774-4-git-send-email-jacob.jun.pan@linux.intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 8 insertions, 29 deletions

diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c
index a35347501d36..8dd77800ff5d 100644
--- a/arch/x86/kernel/apb_timer.c
+++ b/arch/x86/kernel/apb_timer.c
@@ -43,10 +43,11 @@
 
 #include <asm/fixmap.h>
 #include <asm/apb_timer.h>
+#include <asm/mrst.h>
 
 #define APBT_MASK                       CLOCKSOURCE_MASK(32)
 #define APBT_SHIFT                      22
-#define APBT_CLOCKEVENT_RATING          150
+#define APBT_CLOCKEVENT_RATING          110
 #define APBT_CLOCKSOURCE_RATING         250
 #define APBT_MIN_DELTA_USEC             200
 
@@ -83,8 +84,6 @@ struct apbt_dev {
         char name[10];
 };
 
-int disable_apbt_percpu __cpuinitdata;
-
 static DEFINE_PER_CPU(struct apbt_dev, cpu_apbt_dev);
 
 #ifdef CONFIG_SMP
@@ -195,29 +194,6 @@ static struct clock_event_device apbt_clockevent = {
 };
 
 /*
- * if user does not want to use per CPU apb timer, just give it a lower rating
- * than local apic timer and skip the late per cpu timer init.
- */
-static inline int __init setup_x86_mrst_timer(char *arg)
-{
-        if (!arg)
-                return -EINVAL;
-
-        if (strcmp("apbt_only", arg) == 0)
-                disable_apbt_percpu = 0;
-        else if (strcmp("lapic_and_apbt", arg) == 0)
-                disable_apbt_percpu = 1;
-        else {
-                pr_warning("X86 MRST timer option %s not recognised"
-                           " use x86_mrst_timer=apbt_only or lapic_and_apbt\n",
-                           arg);
-                return -EINVAL;
-        }
-        return 0;
-}
-__setup("x86_mrst_timer=", setup_x86_mrst_timer);
-
-/*
  * start count down from 0xffff_ffff. this is done by toggling the enable bit
  * then load initial load count to ~0.
  */
@@ -335,7 +311,7 @@ static int __init apbt_clockevent_register(void)
         adev->num = smp_processor_id();
         memcpy(&adev->evt, &apbt_clockevent, sizeof(struct clock_event_device));
 
-        if (disable_apbt_percpu) {
+        if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
                 apbt_clockevent.rating = APBT_CLOCKEVENT_RATING - 100;
                 global_clock_event = &adev->evt;
                 printk(KERN_DEBUG "%s clockevent registered as global\n",
@@ -429,7 +405,8 @@ static int apbt_cpuhp_notify(struct notifier_block *n,
 
 static __init int apbt_late_init(void)
 {
-        if (disable_apbt_percpu || !apb_timer_block_enabled)
+        if (mrst_timer_options == MRST_TIMER_LAPIC_APBT ||
+                !apb_timer_block_enabled)
                 return 0;
         /* This notifier should be called after workqueue is ready */
         hotcpu_notifier(apbt_cpuhp_notify, -20);
@@ -450,6 +427,8 @@ static void apbt_set_mode(enum clock_event_mode mode,
         int timer_num;
         struct apbt_dev *adev = EVT_TO_APBT_DEV(evt);
 
+        BUG_ON(!apbt_virt_address);
+
         timer_num = adev->num;
         pr_debug("%s CPU %d timer %d mode=%d\n",
                  __func__, first_cpu(*evt->cpumask), timer_num, mode);
@@ -676,7 +655,7 @@ void __init apbt_time_init(void)
         }
 #ifdef CONFIG_SMP
         /* kernel cmdline disable apb timer, so we will use lapic timers */
-        if (disable_apbt_percpu) {
+        if (mrst_timer_options == MRST_TIMER_LAPIC_APBT) {
                 printk(KERN_INFO "apbt: disabled per cpu timer\n");
                 return;
         }