From 7019cc2dd6fafcdc6b104005482dc910dcdbb797 Mon Sep 17 00:00:00 2001 From: Russ Anderson Date: Wed, 9 Jul 2008 15:27:19 -0500 Subject: x86 BIOS interface for RTC on SGI UV Real-time code needs to know the number of cycles per second on SGI UV. The information is provided via a run time BIOS call. This patch provides the linux side of that interface. This is the first of several run time BIOS calls to be defined in uv/bios.h and bios_uv.c. Note that BIOS_CALL() is just a stub for now. The bios side is being worked on. Signed-off-by: Russ Anderson Cc: Jack Steiner Signed-off-by: Ingo Molnar --- arch/x86/kernel/genx2apic_uv_x.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'arch/x86/kernel/genx2apic_uv_x.c') diff --git a/arch/x86/kernel/genx2apic_uv_x.c b/arch/x86/kernel/genx2apic_uv_x.c index 711f11c30b06..3c3929340692 100644 --- a/arch/x86/kernel/genx2apic_uv_x.c +++ b/arch/x86/kernel/genx2apic_uv_x.c @@ -24,6 +24,7 @@ #include #include #include +#include DEFINE_PER_CPU(struct uv_hub_info_s, __uv_hub_info); EXPORT_PER_CPU_SYMBOL_GPL(__uv_hub_info); @@ -40,6 +41,9 @@ EXPORT_SYMBOL_GPL(uv_cpu_to_blade); short uv_possible_blades; EXPORT_SYMBOL_GPL(uv_possible_blades); +unsigned long sn_rtc_cycles_per_second; +EXPORT_SYMBOL(sn_rtc_cycles_per_second); + /* Start with all IRQs pointing to boot CPU. IRQ balancing will shift them. */ static cpumask_t uv_target_cpus(void) @@ -272,6 +276,23 @@ static __init void map_mmioh_high(int max_pnode) map_high("MMIOH", mmioh.s.base, shift, map_uc); } +static __init void uv_rtc_init(void) +{ + long status, ticks_per_sec, drift; + + status = + x86_bios_freq_base(BIOS_FREQ_BASE_REALTIME_CLOCK, &ticks_per_sec, + &drift); + if (status != 0 || ticks_per_sec < 100000) { + printk(KERN_WARNING + "unable to determine platform RTC clock frequency, " + "guessing.\n"); + /* BIOS gives wrong value for clock freq. so guess */ + sn_rtc_cycles_per_second = 1000000000000UL / 30000UL; + } else + sn_rtc_cycles_per_second = ticks_per_sec; +} + static __init void uv_system_init(void) { union uvh_si_addr_map_config_u m_n_config; @@ -326,6 +347,8 @@ static __init void uv_system_init(void) gnode_upper = (((unsigned long)node_id.s.node_id) & ~((1 << n_val) - 1)) << m_val; + uv_rtc_init(); + for_each_present_cpu(cpu) { nid = cpu_to_node(cpu); pnode = uv_apicid_to_pnode(per_cpu(x86_cpu_to_apicid, cpu)); -- cgit v1.2.3