diff options
Diffstat (limited to 'target/linux/x86-2.6/patches/100-scx200_hr_timer.patch')
| -rw-r--r-- | target/linux/x86-2.6/patches/100-scx200_hr_timer.patch | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/target/linux/x86-2.6/patches/100-scx200_hr_timer.patch b/target/linux/x86-2.6/patches/100-scx200_hr_timer.patch new file mode 100644 index 0000000..38fc16a --- /dev/null +++ b/target/linux/x86-2.6/patches/100-scx200_hr_timer.patch @@ -0,0 +1,320 @@ +SCx200 High Resolution Timer Patch for Linux 2.6 +http://www.gnusto.com/scx200-hr-timer.html + +diff -Naurp linux-2.6.12-rc6.orig/arch/i386/Kconfig linux-2.6.12-rc6/arch/i386/Kconfig +--- linux-2.6.12-rc6.orig/arch/i386/Kconfig 2005-06-07 14:56:02.000000000 +0100 ++++ linux-2.6.12-rc6/arch/i386/Kconfig 2005-06-07 16:43:19.000000000 +0100 +@@ -458,6 +458,17 @@ config HPET_EMULATE_RTC + bool "Provide RTC interrupt" + depends on HPET_TIMER && RTC=y + ++config SCx200HR_TIMER ++ bool "NatSemi SCx200 27MHz High-Resolution Timer Support" ++ help ++ Some of the AMD (formerly National Semiconductor) Geode ++ processors, notably the SC1100, suffer from a buggy time ++ stamp counter which causes them to lose time when the ++ processor is sleeping. Enable this option to use the ++ on-board 27Mz high-resolution timer to keep time instead. ++ depends on (SCx200) ++ default n ++ + config SMP + bool "Symmetric multi-processing support" + ---help--- +diff -Naurp linux-2.6.12-rc6.orig/arch/i386/kernel/scx200.c linux-2.6.12-rc6/arch/i386/kernel/scx200.c +--- linux-2.6.12-rc6.orig/arch/i386/kernel/scx200.c 2005-06-07 14:56:02.000000000 +0100 ++++ linux-2.6.12-rc6/arch/i386/kernel/scx200.c 2005-06-07 16:43:19.000000000 +0100 +@@ -27,6 +27,10 @@ long scx200_gpio_shadow[2]; + + unsigned scx200_cb_base = 0; + ++#ifdef CONFIG_SCx200HR_TIMER ++extern void __devinit scx200hr_timer_enable(void); ++#endif ++ + static struct pci_device_id scx200_tbl[] = { + { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SCx200_BRIDGE) }, + { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_SC1100_BRIDGE) }, +@@ -83,6 +87,9 @@ static int __devinit scx200_probe(struct + printk(KERN_INFO NAME ": Configuration Block base 0x%x\n", scx200_cb_base); + } + ++#ifdef CONFIG_SCx200HR_TIMER ++ scx200hr_timer_enable(); ++#endif + return 0; + } + +diff -Naurp linux-2.6.12-rc6.orig/arch/i386/kernel/timers/Makefile linux-2.6.12-rc6/arch/i386/kernel/timers/Makefile +--- linux-2.6.12-rc6.orig/arch/i386/kernel/timers/Makefile 2004-03-11 18:21:13.000000000 +0000 ++++ linux-2.6.12-rc6/arch/i386/kernel/timers/Makefile 2005-06-07 16:43:19.000000000 +0100 +@@ -5,5 +5,6 @@ + obj-y := timer.o timer_none.o timer_tsc.o timer_pit.o common.o + + obj-$(CONFIG_X86_CYCLONE_TIMER) += timer_cyclone.o ++obj-$(CONFIG_SCx200HR_TIMER) += timer_scx200hr.o + obj-$(CONFIG_HPET_TIMER) += timer_hpet.o + obj-$(CONFIG_X86_PM_TIMER) += timer_pm.o +diff -Naurp linux-2.6.12-rc6.orig/arch/i386/kernel/timers/timer.c linux-2.6.12-rc6/arch/i386/kernel/timers/timer.c +--- linux-2.6.12-rc6.orig/arch/i386/kernel/timers/timer.c 2004-12-26 14:07:37.000000000 +0000 ++++ linux-2.6.12-rc6/arch/i386/kernel/timers/timer.c 2005-06-07 16:43:19.000000000 +0100 +@@ -13,6 +13,9 @@ + #endif + /* list of timers, ordered by preference, NULL terminated */ + static struct init_timer_opts* __initdata timers[] = { ++#ifdef CONFIG_SCx200HR_TIMER ++ &timer_scx200hr_init, ++#endif + #ifdef CONFIG_X86_CYCLONE_TIMER + &timer_cyclone_init, + #endif +diff -Naurp linux-2.6.12-rc6.orig/arch/i386/kernel/timers/timer_scx200hr.c linux-2.6.12-rc6/arch/i386/kernel/timers/timer_scx200hr.c +--- linux-2.6.12-rc6.orig/arch/i386/kernel/timers/timer_scx200hr.c 1970-01-01 01:00:00.000000000 +0100 ++++ linux-2.6.12-rc6/arch/i386/kernel/timers/timer_scx200hr.c 2005-06-07 16:43:19.000000000 +0100 +@@ -0,0 +1,220 @@ ++/* ++ * Copyright (C) 2005 Ted Phelps ++ * ++ * This is a clock driver for the Geode SCx200's 27MHz high-resolution ++ * timer as the system clock replacing its buggy time stamp counter. ++ * ++ * Based on parts of timer_hpet.c, timer_tsc.c and timer_pit.c. ++ * ++ * This program is free software; you can redistribute it and/or ++ * modify it under the terms of the GNU General Public License as ++ * published by the Free Software Foundation; either version 2 of the ++ * License, or (at your option) any later version. ++ */ ++ ++#include <asm/timer.h> ++#include <linux/init.h> ++#include <linux/pci.h> ++#include <linux/seq_file.h> ++#include <linux/scx200.h> ++ ++#define NAME "scx200hr" ++ ++/* Read the clock */ ++#define SCx200HR_CLOCK() inl(scx200_cb_base + SCx200_TIMER_OFFSET) ++ ++/* High-resolution timer configuration address */ ++#define SCx200_TMCNFG_OFFSET (SCx200_TIMER_OFFSET + 5) ++ ++/* Set this bit to disable the 27 MHz input clock */ ++#define HR_TM27MPD (1 << 2) ++ ++/* Set this bit to update the count-up timer once per cycle of the ++ * 27MHz timer, clear it to update the timer once every 27 cycles ++ * (effectively producing a 1MHz counter) */ ++#define HR_TMCLKSEL (1 << 1) ++ ++/* Set this bit to enable the high-resolution timer interrupt */ ++#define HR_TMEN (1 << 0) ++ ++/* The frequency of the timer. Change this to 27000000 and set ++ * HR_TMCLKSEL in scx200hr_enable to run at the faster clock rate. At ++ * this point in time there is no point in doing so since times are ++ * recorded in usec except for the monotonic clock, which is only used ++ * by the hangcheck-timer. */ ++#define HR_FREQ 1000000 ++ ++/* The number of cycles of the high-resolution timer we expect to see ++ * in a single tick. Note that the result is <<8 for greater precision*/ ++#define HR_CYCLES_PER_TICK \ ++ (SH_DIV(HR_FREQ / 1000000 * TICK_NSEC, 1000, 8)) ++ ++/* The number of cycles of the high-resolution timer we expect to see ++ * in one microsecond, <<8 */ ++#define HR_CYCLES_PER_US ((HR_FREQ / 1000000) << 8) ++ ++ ++/* The value of the timer at the last interrupt */ ++static u32 clock_at_last_interrupt; ++ ++/* The number of high-resolution clock cycles beyond what we would ++ have expected that the last tick occurred, <<8 for greater precision */ ++static long clock_delay; ++ ++/* The total number of timer nanoseconds between the time the timer ++ * went live and the most recent tick. */ ++static unsigned long long total_ns; ++ ++/* A lock to guard access to the monotonic clock-related variables ++ * (total_ns and clocal_at_last_interrupt). Note that these are also ++ * protected by the xtime lock. */ ++static seqlock_t hr_lock = SEQLOCK_UNLOCKED; ++ ++/* Nonzero if the timer has been selected */ ++static int enable_scx200hr; ++ ++static int __init scx200hr_init(char *override) ++{ ++ /* Watch for a command-line clock= override */ ++ if (override[0] && strncmp(override, NAME, sizeof(NAME) - 1) != 0) { ++ return -ENODEV; ++ } ++ ++ /* Note that we should try to enable this timer once the ++ * configuration block address is known */ ++ printk(KERN_WARNING NAME ": timer not yet accessible; will probe later.\n"); ++ enable_scx200hr = 1; ++ return -EAGAIN; ++} ++ ++/* Called by the timer interrupt. The xtime_lock will be held. */ ++static void mark_offset_scx200hr(void) ++{ ++ u32 now, delta; ++ ++ /* Avoid races between the interrupt handler and monotonic_clock */ ++ write_seqlock(&hr_lock); ++ ++ /* Determine how many cycles have elapsed since the last interrupt */ ++ now = SCx200HR_CLOCK(); ++ delta = (now - clock_at_last_interrupt) << 8; ++ clock_at_last_interrupt = now; ++ ++ /* Update the total us count and remainder */ ++ total_ns += (delta * 1000) / HR_CYCLES_PER_US; ++ ++ /* The monotonic clock is safe now */ ++ write_sequnlock(&hr_lock); ++ ++ /* Adjust for interrupt handling delay */ ++ delta += clock_delay; ++ ++ /* The high-resolution timer is driven by a different crystal ++ * to the main CPU, so there's no guarantee that the 1KHz ++ * interrupt rate will coincide with the timer. This keeps ++ * the jiffies count in line with the high-resolution timer, ++ * which makes it possible for NTP to do its magic */ ++ if (delta < HR_CYCLES_PER_TICK) { ++#if 1 ++ /* Didn't go over 1000us: decrement jiffies to balance ++ * out increment in do_timer. This will cause some ++ * jitter if the frequency offset is large, as that ++ * adjustment will be applied about 1ms late. */ ++ jiffies_64--; ++ clock_delay = delta; ++#else /* !1 */ ++ clock_delay = 0; ++#endif /* 1 */ ++ } else if (delta < (HR_CYCLES_PER_TICK << 1) + (HR_CYCLES_PER_TICK >> 1)) { ++ clock_delay = delta - HR_CYCLES_PER_TICK; ++ } else { ++ jiffies_64 += delta / HR_CYCLES_PER_TICK - 2; ++ clock_delay = HR_CYCLES_PER_TICK + delta % HR_CYCLES_PER_TICK; ++ } ++} ++ ++/* Called by gettimeofday(). Returns the number of microseconds since ++ * the last interrupt. This is called with the xtime_lock held.*/ ++static unsigned long get_offset_scx200hr(void) ++{ ++ u32 delta; ++ ++ /* Get the time now and determine how many cycles have ++ * transpired since the interrupt, adjusting for timer ++ * interrupt jitter. */ ++ delta = ((SCx200HR_CLOCK() - clock_at_last_interrupt) << 8) + clock_delay; ++ ++ /* Convert from cycles<<8 to microseconds */ ++ return delta / HR_CYCLES_PER_US; ++} ++ ++/* Returns the number of nanoseconds since the init of the timer. */ ++static unsigned long long monotonic_clock_scx200hr(void) ++{ ++ u32 delta, seq; ++ unsigned long long ns; ++ ++ /* This function is *not* called with xtime_lock held, so we ++ * need to get the hr_lock to ensure we're not competing with ++ * mark_offset_scx200hr. */ ++ do { ++ seq = read_seqbegin(&hr_lock); ++ ns = total_ns; ++ delta = SCx200HR_CLOCK() - clock_at_last_interrupt; ++ } while (read_seqretry(&hr_lock, seq)); ++ ++ /* Convert cycles to microseconds and add. */ ++ return ns + delta * 1000 / HR_CYCLES_PER_US; ++} ++ ++/* scx200hr timer_opts struct */ ++struct timer_opts timer_scx200hr = { ++ .name = NAME, ++ .mark_offset = mark_offset_scx200hr, ++ .get_offset = get_offset_scx200hr, ++ .monotonic_clock = monotonic_clock_scx200hr, ++ .delay = NULL ++}; ++ ++/* And the init_timer struct */ ++struct init_timer_opts __devinitdata timer_scx200hr_init = { ++ .init = scx200hr_init, ++ .opts = &timer_scx200hr ++}; ++ ++ ++/* Switch from the original timer to the high-resolution timer */ ++void __devinit scx200hr_timer_enable(void) ++{ ++ /* Make sure the timer was requested and that the ++ * configuration block is present */ ++ if (!enable_scx200hr || !scx200_cb_present()) { ++ return; ++ } ++ ++ /* Reserve the timer region for ourselves */ ++ if (!request_region(scx200_cb_base + SCx200_TIMER_OFFSET, ++ SCx200_TIMER_SIZE, ++ "NatSemi SCx200 High-Resolution Timer")) { ++ printk(KERN_WARNING NAME ": unable to lock timer region\n"); ++ return; ++ } ++ ++ /* Configure the timer */ ++ outb(0, scx200_cb_base + SCx200_TMCNFG_OFFSET); ++ ++ /* Record the current value of the timer. */ ++ clock_at_last_interrupt = SCx200HR_CLOCK(); ++ ++ /* Get the current value of the monotonic clock */ ++ total_ns = cur_timer->monotonic_clock(); ++ ++ /* Switch from the original timer functions to ours, but keep ++ * the current delay function since loops_per_jiffy will have ++ * been computed using that */ ++ timer_scx200hr.delay = cur_timer->delay; ++ cur_timer = &timer_scx200hr; ++ ++ printk(KERN_INFO "switching to scx200 high-resolution timer (%lu cpt)\n", ++ HR_CYCLES_PER_TICK); ++} +diff -Naurp linux-2.6.12-rc6.orig/include/asm-i386/timer.h linux-2.6.12-rc6/include/asm-i386/timer.h +--- linux-2.6.12-rc6.orig/include/asm-i386/timer.h 2005-06-07 14:56:11.000000000 +0100 ++++ linux-2.6.12-rc6/include/asm-i386/timer.h 2005-06-07 16:43:19.000000000 +0100 +@@ -50,6 +50,9 @@ extern struct init_timer_opts timer_tsc_ + #ifdef CONFIG_X86_CYCLONE_TIMER + extern struct init_timer_opts timer_cyclone_init; + #endif ++#ifdef CONFIG_SCx200HR_TIMER ++extern struct init_timer_opts timer_scx200hr_init; ++#endif + + extern unsigned long calibrate_tsc(void); + extern void init_cpu_khz(void); +diff -Naurp linux-2.6.12-rc6.orig/include/linux/scx200.h linux-2.6.12-rc6/include/linux/scx200.h +--- linux-2.6.12-rc6.orig/include/linux/scx200.h 2005-06-07 14:56:11.000000000 +0100 ++++ linux-2.6.12-rc6/include/linux/scx200.h 2005-06-07 16:43:19.000000000 +0100 +@@ -32,7 +32,7 @@ extern unsigned scx200_cb_base; + + /* High Resolution Timer */ + #define SCx200_TIMER_OFFSET 0x08 +-#define SCx200_TIMER_SIZE 0x05 ++#define SCx200_TIMER_SIZE 0x06 + + /* Clock Generators */ + #define SCx200_CLOCKGEN_OFFSET 0x10 |