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Date: Mon, 20 Sep 2010 16:59:56 -0700 From: Alok Kataria <akataria@...are.com> To: Thomas Gleixner <tglx@...utronix.de> Cc: "H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...e.hu>, the arch/x86 maintainers <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] x86,apic: V2 Add apic calibration hook. On Mon, 2010-09-20 at 16:34 -0700, Alok Kataria wrote: > Below is the preparatory change, will followup with the 2nd patch which > introduces the actual hook. Below is the 2nd patch. -- Add apic timer calibration hook. From: Alok N Kataria <akataria@...are.com> Add a new function ptr calibrate_apic_clock to x86_init_timers structure. On native this does the usual apic calibration. On VMware's platform we override it with a routine which gets that information from the hypervisor. Signed-off-by: Alok N Kataria <akataria@...are.com> Index: linux-x86-tree.git/arch/x86/include/asm/apic.h =================================================================== --- linux-x86-tree.git.orig/arch/x86/include/asm/apic.h 2010-09-20 16:05:58.000000000 -0700 +++ linux-x86-tree.git/arch/x86/include/asm/apic.h 2010-09-20 16:36:42.000000000 -0700 @@ -17,6 +17,10 @@ #define ARCH_APICTIMER_STOPS_ON_C3 1 +/* Clock divisor */ +#define APIC_DIVISOR 16 +#define LAPIC_CAL_LOOPS (HZ/10) + /* * Debugging macros */ @@ -238,6 +242,8 @@ extern void setup_boot_APIC_clock(void); extern void setup_secondary_APIC_clock(void); extern int APIC_init_uniprocessor(void); extern void enable_NMI_through_LVT0(void); +extern int native_calibrate_apic_clock(void); +extern int initialize_lapic_timer(long delta, unsigned int calibration_result); /* * On 32bit this is mach-xxx local Index: linux-x86-tree.git/arch/x86/include/asm/x86_init.h =================================================================== --- linux-x86-tree.git.orig/arch/x86/include/asm/x86_init.h 2010-09-20 16:06:11.000000000 -0700 +++ linux-x86-tree.git/arch/x86/include/asm/x86_init.h 2010-09-20 16:54:08.000000000 -0700 @@ -83,11 +83,13 @@ struct x86_init_paging { * boot cpu * @tsc_pre_init: platform function called before TSC init * @timer_init: initialize the platform timer (default PIT/HPET) + * @calibrate_apic_clock: calibrate APIC clock freq (ticks per HZ) */ struct x86_init_timers { void (*setup_percpu_clockev)(void); void (*tsc_pre_init)(void); void (*timer_init)(void); + int (*calibrate_apic_clock)(void); }; /** Index: linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c =================================================================== --- linux-x86-tree.git.orig/arch/x86/kernel/cpu/vmware.c 2010-09-20 16:05:30.000000000 -0700 +++ linux-x86-tree.git/arch/x86/kernel/cpu/vmware.c 2010-09-20 16:40:35.000000000 -0700 @@ -26,6 +26,7 @@ #include <asm/div64.h> #include <asm/x86_init.h> #include <asm/hypervisor.h> +#include <asm/apic.h> #define CPUID_VMWARE_INFO_LEAF 0x40000000 #define VMWARE_HYPERVISOR_MAGIC 0x564D5868 @@ -72,17 +73,40 @@ static unsigned long vmware_get_tsc_khz( return tsc_hz; } +static int __init vmware_calibrate_apic_clock(void) +{ + unsigned int calibration_result; + uint32_t eax, ebx, ecx, edx; + int err; + long delta; + unsigned long flags; + + VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); + BUG_ON(!ecx); + calibration_result = ecx / HZ; + + printk(KERN_INFO "APIC bus freq read from hypervisor\n"); + + delta = (calibration_result * LAPIC_CAL_LOOPS) / APIC_DIVISOR; + local_irq_save(flags); + err = initialize_lapic_timer(delta, calibration_result); + local_irq_restore(flags); + + return err; +} + static void __init vmware_platform_setup(void) { uint32_t eax, ebx, ecx, edx; VMWARE_PORT(GETHZ, eax, ebx, ecx, edx); - if (ebx != UINT_MAX) + if (ebx != UINT_MAX) { x86_platform.calibrate_tsc = vmware_get_tsc_khz; - else + x86_init.timers.calibrate_apic_clock = vmware_calibrate_apic_clock; + } else printk(KERN_WARNING - "Failed to get TSC freq from the hypervisor\n"); + "Failed to setup VMware hypervisor platform\n"); } /* Index: linux-x86-tree.git/arch/x86/kernel/x86_init.c =================================================================== --- linux-x86-tree.git.orig/arch/x86/kernel/x86_init.c 2010-09-20 16:05:07.000000000 -0700 +++ linux-x86-tree.git/arch/x86/kernel/x86_init.c 2010-09-20 16:41:21.000000000 -0700 @@ -68,6 +68,7 @@ struct x86_init_ops x86_init __initdata .setup_percpu_clockev = setup_boot_APIC_clock, .tsc_pre_init = x86_init_noop, .timer_init = hpet_time_init, + .calibrate_apic_clock = native_calibrate_apic_clock }, .iommu = { Index: linux-x86-tree.git/arch/x86/kernel/apic/apic.c =================================================================== --- linux-x86-tree.git.orig/arch/x86/kernel/apic/apic.c 2010-09-20 16:10:13.000000000 -0700 +++ linux-x86-tree.git/arch/x86/kernel/apic/apic.c 2010-09-20 16:42:12.000000000 -0700 @@ -326,13 +326,6 @@ int lapic_get_maxlvt(void) } /* - * Local APIC timer - */ - -/* Clock divisor */ -#define APIC_DIVISOR 16 - -/* * This function sets up the local APIC timer, with a timeout of * 'clocks' APIC bus clock. During calibration we actually call * this function twice on the boot CPU, once with a bogus timeout @@ -500,8 +493,6 @@ static void __cpuinit setup_APIC_timer(v * back to normal later in the boot process). */ -#define LAPIC_CAL_LOOPS (HZ/10) - static __initdata int lapic_cal_loops = -1; static __initdata long lapic_cal_t1, lapic_cal_t2; static __initdata unsigned long long lapic_cal_tsc1, lapic_cal_tsc2; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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