From 83d7384f8d4aa216b49cf9cb286ea743054b119f Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Fri, 12 Oct 2007 23:04:06 +0200 Subject: x86: Geode Multi-Function General Purpose Timers support This adds support for Multi-Function General Purpose Timers. It detects the available timers during southbridge init, and provides an API for allocating and setting the timers. They're higher resolution than the standard PIT, so the MFGPTs come in handy for quite a few things. Note that we never clobber the timers that the BIOS might have opted to use; we just check for unused timers. Signed-off-by: Jordan Crouse Signed-off-by: Andres Salomon Cc: Andi Kleen Cc: Alan Cox Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a57c1f216b21..2128de6d80ea 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1160,6 +1160,9 @@ and is between 256 and 4096 characters. It is defined in the file nomce [X86-32] Machine Check Exception + nomfgpt [X86-32] Disable Multi-Function General Purpose + Timer usage (for AMD Geode machines). + noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops noreplace-smp [X86-32,SMP] Don't replace SMP instructions -- cgit v1.2.3 From 8f36881b3c972ebc019195692849f22488f9c0a3 Mon Sep 17 00:00:00 2001 From: Andres Salomon Date: Fri, 12 Oct 2007 23:04:06 +0200 Subject: x86: Geode MFGPT clock event device support Add support for an MFGPT clock event device; this allows us to use MFGPTs as the basis for high-resolution timers. Signed-off-by: Jordan Crouse Signed-off-by: Andres Salomon Cc: Andi Kleen Cc: Alan Cox Cc: john stultz Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 4 + arch/i386/Kconfig | 10 +++ arch/x86/kernel/mfgpt_32.c | 165 ++++++++++++++++++++++++++++++++++++ 3 files changed, 179 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2128de6d80ea..f27cdd7125f2 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1009,6 +1009,10 @@ and is between 256 and 4096 characters. It is defined in the file meye.*= [HW] Set MotionEye Camera parameters See Documentation/video4linux/meye.txt. + mfgpt_irq= [IA-32] Specify the IRQ to use for the + Multi-Function General Purpose Timers on AMD Geode + platforms. + mga= [HW,DRM] mousedev.tap_time= diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 2d85e4b87307..6bbbc2755e44 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -1206,6 +1206,16 @@ config SCx200HR_TIMER processor goes idle (as is done by the scheduler). The other workaround is idle=poll boot option. +config GEODE_MFGPT_TIMER + bool "Geode Multi-Function General Purpose Timer (MFGPT) events" + depends on MGEODE_LX && GENERIC_TIME && GENERIC_CLOCKEVENTS + default y + help + This driver provides a clock event source based on the MFGPT + timer(s) in the CS5535 and CS5536 companion chip for the geode. + MFGPTs have a better resolution and max interval than the + generic PIT, and are suitable for use as high-res timers. + config K8_NB def_bool y depends on AGP_AMD64 diff --git a/arch/x86/kernel/mfgpt_32.c b/arch/x86/kernel/mfgpt_32.c index 3a63a2dd8d27..0ab680f2d9db 100644 --- a/arch/x86/kernel/mfgpt_32.c +++ b/arch/x86/kernel/mfgpt_32.c @@ -48,6 +48,12 @@ static struct mfgpt_timer_t { #define MFGPT_HZ (32000 / MFGPT_DIVISOR) #define MFGPT_PERIODIC (MFGPT_HZ / HZ) +#ifdef CONFIG_GEODE_MFGPT_TIMER +static int __init mfgpt_timer_setup(void); +#else +#define mfgpt_timer_setup() (0) +#endif + /* Allow for disabling of MFGPTs */ static int disable; static int __init mfgpt_disable(char *s) @@ -82,6 +88,9 @@ int __init geode_mfgpt_detect(void) } } + /* set up clock event device, if desired */ + i = mfgpt_timer_setup(); + return count; } @@ -195,3 +204,159 @@ int geode_mfgpt_alloc_timer(int timer, int domain, struct module *owner) return -1; } + +#ifdef CONFIG_GEODE_MFGPT_TIMER + +/* + * The MFPGT timers on the CS5536 provide us with suitable timers to use + * as clock event sources - not as good as a HPET or APIC, but certainly + * better then the PIT. This isn't a general purpose MFGPT driver, but + * a simplified one designed specifically to act as a clock event source. + * For full details about the MFGPT, please consult the CS5536 data sheet. + */ + +#include +#include + +static unsigned int mfgpt_tick_mode = CLOCK_EVT_MODE_SHUTDOWN; +static u16 mfgpt_event_clock; + +static int irq = 7; +static int __init mfgpt_setup(char *str) +{ + get_option(&str, &irq); + return 1; +} +__setup("mfgpt_irq=", mfgpt_setup); + +static inline void mfgpt_disable_timer(u16 clock) +{ + u16 val = geode_mfgpt_read(clock, MFGPT_REG_SETUP); + geode_mfgpt_write(clock, MFGPT_REG_SETUP, val & ~MFGPT_SETUP_CNTEN); +} + +static int mfgpt_next_event(unsigned long, struct clock_event_device *); +static void mfgpt_set_mode(enum clock_event_mode, struct clock_event_device *); + +static struct clock_event_device mfgpt_clockevent = { + .name = "mfgpt-timer", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = mfgpt_set_mode, + .set_next_event = mfgpt_next_event, + .rating = 250, + .cpumask = CPU_MASK_ALL, + .shift = 32 +}; + +static inline void mfgpt_start_timer(u16 clock, u16 delta) +{ + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_CMP2, (u16) delta); + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_COUNTER, 0); + + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_SETUP, + MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2); +} + +static void mfgpt_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + mfgpt_disable_timer(mfgpt_event_clock); + + if (mode == CLOCK_EVT_MODE_PERIODIC) + mfgpt_start_timer(mfgpt_event_clock, MFGPT_PERIODIC); + + mfgpt_tick_mode = mode; +} + +static int mfgpt_next_event(unsigned long delta, struct clock_event_device *evt) +{ + mfgpt_start_timer(mfgpt_event_clock, delta); + return 0; +} + +/* Assume (foolishly?), that this interrupt was due to our tick */ + +static irqreturn_t mfgpt_tick(int irq, void *dev_id) +{ + if (mfgpt_tick_mode == CLOCK_EVT_MODE_SHUTDOWN) + return IRQ_HANDLED; + + /* Turn off the clock */ + mfgpt_disable_timer(mfgpt_event_clock); + + /* Clear the counter */ + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_COUNTER, 0); + + /* Restart the clock in periodic mode */ + + if (mfgpt_tick_mode == CLOCK_EVT_MODE_PERIODIC) { + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_SETUP, + MFGPT_SETUP_CNTEN | MFGPT_SETUP_CMP2); + } + + mfgpt_clockevent.event_handler(&mfgpt_clockevent); + return IRQ_HANDLED; +} + +static struct irqaction mfgptirq = { + .handler = mfgpt_tick, + .flags = IRQF_DISABLED | IRQF_NOBALANCING, + .mask = CPU_MASK_NONE, + .name = "mfgpt-timer" +}; + +static int __init mfgpt_timer_setup(void) +{ + int timer, ret; + u16 val; + + timer = geode_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING, + THIS_MODULE); + if (timer < 0) { + printk(KERN_ERR + "mfgpt-timer: Could not allocate a MFPGT timer\n"); + return -ENODEV; + } + + mfgpt_event_clock = timer; + /* Set the clock scale and enable the event mode for CMP2 */ + val = MFGPT_SCALE | (3 << 8); + + geode_mfgpt_write(mfgpt_event_clock, MFGPT_REG_SETUP, val); + + /* Set up the IRQ on the MFGPT side */ + if (geode_mfgpt_setup_irq(mfgpt_event_clock, MFGPT_CMP2, irq)) { + printk(KERN_ERR "mfgpt-timer: Could not set up IRQ %d\n", irq); + return -EIO; + } + + /* And register it with the kernel */ + ret = setup_irq(irq, &mfgptirq); + + if (ret) { + printk(KERN_ERR + "mfgpt-timer: Unable to set up the interrupt.\n"); + goto err; + } + + /* Set up the clock event */ + mfgpt_clockevent.mult = div_sc(MFGPT_HZ, NSEC_PER_SEC, 32); + mfgpt_clockevent.min_delta_ns = clockevent_delta2ns(0xF, + &mfgpt_clockevent); + mfgpt_clockevent.max_delta_ns = clockevent_delta2ns(0xFFFE, + &mfgpt_clockevent); + + printk(KERN_INFO + "mfgpt-timer: registering the MFGT timer as a clock event.\n"); + clockevents_register_device(&mfgpt_clockevent); + + return 0; + +err: + geode_mfgpt_release_irq(mfgpt_event_clock, MFGPT_CMP2, irq); + printk(KERN_ERR + "mfgpt-timer: Unable to set up the MFGPT clock source\n"); + return -EIO; +} + +#endif -- cgit v1.2.3