Marcelo, All,
This patch fixes gettimeofday for multi-node Summit based systems (IBM
x440, etc). These systems suffer from TSC skew, and thus require an
alternate high res time source. This patch allows do_gettimeofday to
access a register on the cyclone chip found on these systems, which
functions as a global time source.
Please consider for acceptance.
thanks
-john
diff -Nru a/arch/i386/config.in b/arch/i386/config.in
--- a/arch/i386/config.in Mon Dec 16 13:56:13 2002
+++ b/arch/i386/config.in Mon Dec 16 13:56:13 2002
@@ -231,9 +231,11 @@
fi
fi
-bool 'Unsynced TSC support' CONFIG_X86_TSC_DISABLE
-if [ "$CONFIG_X86_TSC_DISABLE" != "y" -a "$CONFIG_X86_HAS_TSC" = "y" ]; then
- define_bool CONFIG_X86_TSC y
+if [ "$CONFIG_X86_NUMA" != "y" ]; then
+ bool 'Unsynced TSC support' CONFIG_X86_TSC_DISABLE
+ if [ "$CONFIG_X86_TSC_DISABLE" != "y" -a "$CONFIG_X86_HAS_TSC" = "y" ]; then
+ define_bool CONFIG_X86_TSC y
+ fi
fi
if [ "$CONFIG_SMP" = "y" -a "$CONFIG_X86_CMPXCHG" = "y" ]; then
diff -Nru a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
--- a/arch/i386/kernel/time.c Mon Dec 16 13:56:13 2002
+++ b/arch/i386/kernel/time.c Mon Dec 16 13:56:13 2002
@@ -256,12 +256,177 @@
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
+
+/* IBM Summit (EXA) Cyclone Timer code*/
+#ifdef CONFIG_X86_SUMMIT
+
+#define CYCLONE_CBAR_ADDR 0xFEB00CD0
+#define CYCLONE_PMCC_OFFSET 0x51A0
+#define CYCLONE_MPMC_OFFSET 0x51D0
+#define CYCLONE_MPCS_OFFSET 0x51A8
+#define CYCLONE_TIMER_FREQ 100000000
+
+int use_cyclone = 0;
+int __init cyclone_setup(char *str)
+{
+ use_cyclone = 1;
+ return 1;
+}
+
+static u32* volatile cyclone_timer; /* Cyclone MPMC0 register */
+static u32 last_cyclone_timer;
+
+static inline void mark_timeoffset_cyclone(void)
+{
+ int count;
+ spin_lock(&i8253_lock);
+ /* quickly read the cyclone timer */
+ if(cyclone_timer)
+ last_cyclone_timer = cyclone_timer[0];
+
+ /* calculate delay_at_last_interrupt */
+ outb_p(0x00, 0x43); /* latch the count ASAP */
+
+ count = inb_p(0x40); /* read the latched count */
+ count |= inb(0x40) << 8;
+ spin_unlock(&i8253_lock);
+
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ delay_at_last_interrupt = (count + LATCH/2) / LATCH;
+}
+
+static unsigned long do_gettimeoffset_cyclone(void)
+{
+ u32 offset;
+
+ if(!cyclone_timer)
+ return delay_at_last_interrupt;
+
+ /* Read the cyclone timer */
+ offset = cyclone_timer[0];
+
+ /* .. relative to previous jiffy */
+ offset = offset - last_cyclone_timer;
+
+ /* convert cyclone ticks to microseconds */
+ /* XXX slow, can we speed this up? */
+ offset = offset/(CYCLONE_TIMER_FREQ/1000000);
+
+ /* our adjusted time offset in microseconds */
+ return delay_at_last_interrupt + offset;
+}
+
+static void __init init_cyclone_clock(void)
+{
+ u32* reg;
+ u32 base; /* saved cyclone base address */
+ u32 pageaddr; /* page that contains cyclone_timer register */
+ u32 offset; /* offset from pageaddr to cyclone_timer register */
+ int i;
+
+ printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
+
+ /* find base address */
+ pageaddr = (CYCLONE_CBAR_ADDR)&PAGE_MASK;
+ offset = (CYCLONE_CBAR_ADDR)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+ use_cyclone = 0;
+ return;
+ }
+ base = *reg;
+ if(!base){
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+ use_cyclone = 0;
+ return;
+ }
+
+ /* setup PMCC */
+ pageaddr = (base + CYCLONE_PMCC_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_PMCC_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+ use_cyclone = 0;
+ return;
+ }
+ reg[0] = 0x00000001;
+
+ /* setup MPCS */
+ pageaddr = (base + CYCLONE_MPCS_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_MPCS_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!reg){
+ printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+ use_cyclone = 0;
+ return;
+ }
+ reg[0] = 0x00000001;
+
+ /* map in cyclone_timer */
+ pageaddr = (base + CYCLONE_MPMC_OFFSET)&PAGE_MASK;
+ offset = (base + CYCLONE_MPMC_OFFSET)&(~PAGE_MASK);
+ set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
+ cyclone_timer = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
+ if(!cyclone_timer){
+ printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
+ use_cyclone = 0;
+ return;
+ }
+
+ /*quick test to make sure its ticking*/
+ for(i=0; i<3; i++){
+ u32 old = cyclone_timer[0];
+ int stall = 100;
+ while(stall--) barrier();
+ if(cyclone_timer[0] == old){
+ printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+ cyclone_timer = 0;
+ use_cyclone = 0;
+ return;
+ }
+ }
+ /* Everything looks good, so set do_gettimeoffset */
+ do_gettimeoffset = do_gettimeoffset_cyclone;
+}
+void __cyclone_delay(unsigned long loops)
+{
+ unsigned long bclock, now;
+ if(!cyclone_timer)
+ return;
+ bclock = cyclone_timer[0];
+ do {
+ rep_nop();
+ now = cyclone_timer[0];
+ } while ((now-bclock) < loops);
+}
+#endif /* CONFIG_X86_SUMMIT */
+
#else
#define do_gettimeoffset() do_fast_gettimeoffset()
#endif
+/* No-cyclone stubs */
+#ifndef CONFIG_X86_SUMMIT
+int __init cyclone_setup(char *str)
+{
+ printk(KERN_ERR "cyclone: Kernel not compiled with CONFIG_X86_SUMMIT, cannot use the cyclone-timer.\n");
+ return 1;
+}
+
+const int use_cyclone = 0;
+static void mark_timeoffset_cyclone(void) {}
+static unsigned long do_gettimeoffset_cyclone(void) {return 0;}
+static void init_cyclone_clock(void) {}
+void __cyclone_delay(unsigned long loops) {}
+#endif /* CONFIG_X86_SUMMIT */
+
/*
* This version of gettimeofday has microsecond resolution
* and better than microsecond precision on fast x86 machines with TSC.
@@ -481,8 +646,9 @@
*/
write_lock(&xtime_lock);
- if (use_tsc)
- {
+ if(use_cyclone)
+ mark_timeoffset_cyclone();
+ else if (use_tsc) {
/*
* It is important that these two operations happen almost at
* the same time. We do the RDTSC stuff first, since it's
@@ -531,7 +697,7 @@
count = ((LATCH-1) - count) * TICK_SIZE;
delay_at_last_interrupt = (count + LATCH/2) / LATCH;
}
-
+
do_timer_interrupt(irq, NULL, regs);
write_unlock(&xtime_lock);
@@ -692,21 +858,30 @@
*/
dodgy_tsc();
-
+
+ if(use_cyclone)
+ init_cyclone_clock();
+
if (cpu_has_tsc) {
unsigned long tsc_quotient = calibrate_tsc();
if (tsc_quotient) {
fast_gettimeoffset_quotient = tsc_quotient;
- use_tsc = 1;
- /*
- * We could be more selective here I suspect
- * and just enable this for the next intel chips ?
+ /* XXX: This is messy
+ * However, we want to allow for the cyclone timer
+ * to work w/ or w/o the TSCs being avaliable
+ * -johnstul@us.ibm.com
*/
- x86_udelay_tsc = 1;
+ if(!use_cyclone){
+ /*
+ * We could be more selective here I suspect
+ * and just enable this for the next intel chips ?
+ */
+ use_tsc = 1;
+ x86_udelay_tsc = 1;
#ifndef do_gettimeoffset
- do_gettimeoffset = do_fast_gettimeoffset;
+ do_gettimeoffset = do_fast_gettimeoffset;
#endif
-
+ }
/* report CPU clock rate in Hz.
* The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
* clock/second. Our precision is about 100 ppm.
@@ -720,6 +895,7 @@
}
}
}
+
#ifdef CONFIG_VISWS
printk("Starting Cobalt Timer system clock\n");
diff -Nru a/arch/i386/lib/delay.c b/arch/i386/lib/delay.c
--- a/arch/i386/lib/delay.c Mon Dec 16 13:56:13 2002
+++ b/arch/i386/lib/delay.c Mon Dec 16 13:56:13 2002
@@ -56,10 +56,13 @@
:"=&a" (d0)
:"0" (loops));
}
-
+extern __cyclone_delay(unsigned long loops);
+extern int use_cyclone;
void __delay(unsigned long loops)
{
- if (x86_udelay_tsc)
+ if (use_cyclone)
+ __cyclone_delay(loops);
+ else if (x86_udelay_tsc)
__rdtsc_delay(loops);
else
__loop_delay(loops);
diff -Nru a/include/asm-i386/fixmap.h b/include/asm-i386/fixmap.h
--- a/include/asm-i386/fixmap.h Mon Dec 16 13:56:13 2002
+++ b/include/asm-i386/fixmap.h Mon Dec 16 13:56:13 2002
@@ -64,6 +64,9 @@
#ifndef CONFIG_X86_F00F_WORKS_OK
FIX_F00F,
#endif
+#ifdef CONFIG_X86_SUMMIT
+ FIX_CYCLONE_TIMER, /*cyclone timer register*/
+#endif
#ifdef CONFIG_HIGHMEM
FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
diff -Nru a/include/asm-i386/smpboot.h b/include/asm-i386/smpboot.h
--- a/include/asm-i386/smpboot.h Mon Dec 16 13:56:13 2002
+++ b/include/asm-i386/smpboot.h Mon Dec 16 13:56:13 2002
@@ -14,6 +14,8 @@
extern unsigned char esr_disable;
extern unsigned char int_delivery_mode;
extern unsigned int int_dest_addr_mode;
+extern int cyclone_setup(char*);
+
static inline void detect_clustered_apic(char* oem, char* prod)
{
/*
@@ -25,6 +27,8 @@
int_dest_addr_mode = APIC_DEST_PHYSICAL;
int_delivery_mode = dest_Fixed;
esr_disable = 1;
+ /*Start cyclone clock*/
+ cyclone_setup(0);
}
else if (!strncmp(oem, "IBM NUMA", 8)){
clustered_apic_mode = CLUSTERED_APIC_NUMAQ;
-
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This archive was generated by hypermail 2b29 : Mon Dec 23 2002 - 22:00:14 EST