From: Ralf Baechle Date: Thu, 11 Oct 2007 22:46:10 +0000 (+0100) Subject: [MIPS] i8253 PIT clocksource and clockevent drivers X-Git-Tag: v2.6.24-rc1~1455^2~31 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=d865bea4dace1d42995a6cf552bc4863842623f4;p=linux-2.6-omap-h63xx.git [MIPS] i8253 PIT clocksource and clockevent drivers Derived from the i386 variant with a few x86 complexities chopped off. Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index d8c905840af..f943736541c 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -65,6 +65,7 @@ config MIPS_COBALT bool "Cobalt Server" select DMA_NONCOHERENT select HW_HAS_PCI + select I8253 select I8259 select IRQ_CPU select IRQ_GT641XX @@ -112,6 +113,7 @@ config MACH_JAZZ select ARCH_MAY_HAVE_PC_FDC select GENERIC_ISA_DMA select IRQ_CPU + select I8253 select I8259 select ISA select PCSPEAKER @@ -201,6 +203,7 @@ config MIPS_MALTA select GENERIC_ISA_DMA select IRQ_CPU select HW_HAS_PCI + select I8253 select I8259 select MIPS_BOARDS_GEN select MIPS_BONITO64 @@ -334,6 +337,7 @@ config QEMU select DMA_COHERENT select GENERIC_ISA_DMA select HAVE_STD_PC_SERIAL_PORT + select I8253 select I8259 select IRQ_CPU select ISA @@ -362,6 +366,7 @@ config SGI_IP22 select BOOT_ELF32 select DMA_NONCOHERENT select HW_HAS_EISA + select I8253 select IP22_CPU_SCACHE select IRQ_CPU select GENERIC_ISA_DMA_SUPPORT_BROKEN @@ -534,6 +539,7 @@ config SNI_RM select HW_HAS_EISA select HW_HAS_PCI select IRQ_CPU + select I8253 select I8259 select ISA select PCSPEAKER @@ -1893,6 +1899,9 @@ config MMU bool default y +config I8253 + bool + config PCSPEAKER bool diff --git a/arch/mips/cobalt/setup.c b/arch/mips/cobalt/setup.c index 5d2e8790b28..345e4ae998d 100644 --- a/arch/mips/cobalt/setup.c +++ b/arch/mips/cobalt/setup.c @@ -15,6 +15,7 @@ #include #include +#include #include #include #include @@ -84,6 +85,11 @@ static struct resource cobalt_reserved_resources[] = { }, }; +void __init plat_time_init(void) +{ + setup_pit_timer(); +} + void __init plat_mem_setup(void) { int i; diff --git a/arch/mips/jazz/setup.c b/arch/mips/jazz/setup.c index fa890df3658..2a7ec08b6ba 100644 --- a/arch/mips/jazz/setup.c +++ b/arch/mips/jazz/setup.c @@ -25,6 +25,7 @@ #include #include +#include #include #include #include @@ -63,6 +64,11 @@ static struct resource jazz_io_resources[] = { } }; +void __init plat_time_init(void) +{ + setup_pit_timer(); +} + void __init plat_mem_setup(void) { int i; diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile index 7851b4b447d..a2689f93c16 100644 --- a/arch/mips/kernel/Makefile +++ b/arch/mips/kernel/Makefile @@ -65,6 +65,7 @@ obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_64BIT) += cpu-bugs64.o +obj-$(CONFIG_I8253) += i8253.o obj-$(CONFIG_PCSPEAKER) += pcspeaker.o obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c new file mode 100644 index 00000000000..5d9830df359 --- /dev/null +++ b/arch/mips/kernel/i8253.c @@ -0,0 +1,213 @@ +/* + * i8253.c 8253/PIT functions + * + */ +#include +#include +#include +#include +#include +#include + +#include +#include +#include + +static DEFINE_SPINLOCK(i8253_lock); + +/* + * Initialize the PIT timer. + * + * This is also called after resume to bring the PIT into operation again. + */ +static void init_pit_timer(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + + switch(mode) { + case CLOCK_EVT_MODE_PERIODIC: + /* binary, mode 2, LSB/MSB, ch 0 */ + outb_p(0x34, PIT_MODE); + outb_p(LATCH & 0xff , PIT_CH0); /* LSB */ + outb(LATCH >> 8 , PIT_CH0); /* MSB */ + break; + + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + if (evt->mode == CLOCK_EVT_MODE_PERIODIC || + evt->mode == CLOCK_EVT_MODE_ONESHOT) { + outb_p(0x30, PIT_MODE); + outb_p(0, PIT_CH0); + outb_p(0, PIT_CH0); + } + break; + + case CLOCK_EVT_MODE_ONESHOT: + /* One shot setup */ + outb_p(0x38, PIT_MODE); + break; + + case CLOCK_EVT_MODE_RESUME: + /* Nothing to do here */ + break; + } + spin_unlock_irqrestore(&i8253_lock, flags); +} + +/* + * Program the next event in oneshot mode + * + * Delta is given in PIT ticks + */ +static int pit_next_event(unsigned long delta, struct clock_event_device *evt) +{ + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + outb_p(delta & 0xff , PIT_CH0); /* LSB */ + outb(delta >> 8 , PIT_CH0); /* MSB */ + spin_unlock_irqrestore(&i8253_lock, flags); + + return 0; +} + +/* + * On UP the PIT can serve all of the possible timer functions. On SMP systems + * it can be solely used for the global tick. + * + * The profiling and update capabilites are switched off once the local apic is + * registered. This mechanism replaces the previous #ifdef LOCAL_APIC - + * !using_apic_timer decisions in do_timer_interrupt_hook() + */ +struct clock_event_device pit_clockevent = { + .name = "pit", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_mode = init_pit_timer, + .set_next_event = pit_next_event, + .shift = 32, + .irq = 0, +}; + +irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + pit_clockevent.event_handler(&pit_clockevent); + + return IRQ_HANDLED; +} + +static struct irqaction irq0 = { + .handler = timer_interrupt, + .flags = IRQF_DISABLED | IRQF_NOBALANCING, + .mask = CPU_MASK_NONE, + .name = "timer" +}; + +/* + * Initialize the conversion factor and the min/max deltas of the clock event + * structure and register the clock event source with the framework. + */ +void __init setup_pit_timer(void) +{ + /* + * Start pit with the boot cpu mask and make it global after the + * IO_APIC has been initialized. + */ + pit_clockevent.cpumask = cpumask_of_cpu(0); + pit_clockevent.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, 32); + pit_clockevent.max_delta_ns = + clockevent_delta2ns(0x7FFF, &pit_clockevent); + pit_clockevent.min_delta_ns = + clockevent_delta2ns(0xF, &pit_clockevent); + clockevents_register_device(&pit_clockevent); + + irq0.mask = cpumask_of_cpu(0); + setup_irq(0, &irq0); +} + +/* + * Since the PIT overflows every tick, its not very useful + * to just read by itself. So use jiffies to emulate a free + * running counter: + */ +static cycle_t pit_read(void) +{ + unsigned long flags; + int count; + u32 jifs; + static int old_count; + static u32 old_jifs; + + spin_lock_irqsave(&i8253_lock, flags); + /* + * Although our caller may have the read side of xtime_lock, + * this is now a seqlock, and we are cheating in this routine + * by having side effects on state that we cannot undo if + * there is a collision on the seqlock and our caller has to + * retry. (Namely, old_jifs and old_count.) So we must treat + * jiffies as volatile despite the lock. We read jiffies + * before latching the timer count to guarantee that although + * the jiffies value might be older than the count (that is, + * the counter may underflow between the last point where + * jiffies was incremented and the point where we latch the + * count), it cannot be newer. + */ + jifs = jiffies; + outb_p(0x00, PIT_MODE); /* latch the count ASAP */ + count = inb_p(PIT_CH0); /* read the latched count */ + count |= inb_p(PIT_CH0) << 8; + + /* VIA686a test code... reset the latch if count > max + 1 */ + if (count > LATCH) { + outb_p(0x34, PIT_MODE); + outb_p(LATCH & 0xff, PIT_CH0); + outb(LATCH >> 8, PIT_CH0); + count = LATCH - 1; + } + + /* + * It's possible for count to appear to go the wrong way for a + * couple of reasons: + * + * 1. The timer counter underflows, but we haven't handled the + * resulting interrupt and incremented jiffies yet. + * 2. Hardware problem with the timer, not giving us continuous time, + * the counter does small "jumps" upwards on some Pentium systems, + * (see c't 95/10 page 335 for Neptun bug.) + * + * Previous attempts to handle these cases intelligently were + * buggy, so we just do the simple thing now. + */ + if (count > old_count && jifs == old_jifs) { + count = old_count; + } + old_count = count; + old_jifs = jifs; + + spin_unlock_irqrestore(&i8253_lock, flags); + + count = (LATCH - 1) - count; + + return (cycle_t)(jifs * LATCH) + count; +} + +static struct clocksource clocksource_pit = { + .name = "pit", + .rating = 110, + .read = pit_read, + .mask = CLOCKSOURCE_MASK(32), + .mult = 0, + .shift = 20, +}; + +static int __init init_pit_clocksource(void) +{ + if (num_possible_cpus() > 1) /* PIT does not scale! */ + return 0; + + clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20); + return clocksource_register(&clocksource_pit); +} +arch_initcall(init_pit_clocksource); diff --git a/arch/mips/mips-boards/generic/time.c b/arch/mips/mips-boards/generic/time.c index cf55ecd96bf..4fab3b2e873 100644 --- a/arch/mips/mips-boards/generic/time.c +++ b/arch/mips/mips-boards/generic/time.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include #include @@ -141,6 +142,9 @@ void __init plat_time_init(void) cpu_khz = est_freq / 1000; mips_scroll_message(); +#ifdef CONFIG_I8253 /* Only Malta has a PIT */ + setup_pit_timer(); +#endif } //static irqreturn_t mips_perf_interrupt(int irq, void *dev_id) diff --git a/arch/mips/qemu/q-setup.c b/arch/mips/qemu/q-setup.c index 89a207650ce..23d34c1917c 100644 --- a/arch/mips/qemu/q-setup.c +++ b/arch/mips/qemu/q-setup.c @@ -1,4 +1,6 @@ #include + +#include #include #include @@ -11,12 +13,9 @@ const char *get_system_type(void) return "Qemu"; } -void __init plat_timer_setup(struct irqaction *irq) +void __init plat_time_init(void) { - /* set the clock to 100 Hz */ - outb_p(0x34,0x43); /* binary, mode 2, LSB/MSB, ch 0 */ - outb_p(LATCH & 0xff , 0x40); /* LSB */ - outb(LATCH >> 8 , 0x40); /* MSB */ + setup_pit_timer(); } void __init plat_mem_setup(void) diff --git a/arch/mips/sgi-ip22/ip22-time.c b/arch/mips/sgi-ip22/ip22-time.c index a1df1f9e26f..9b9bffd2e8f 100644 --- a/arch/mips/sgi-ip22/ip22-time.c +++ b/arch/mips/sgi-ip22/ip22-time.c @@ -20,6 +20,7 @@ #include #include +#include #include #include #include @@ -172,6 +173,9 @@ __init void plat_time_init(void) (int) (r4k_tick % (500000 / HZ))); mips_hpt_frequency = r4k_tick * HZ; + + if (ip22_is_fullhouse()) + setup_pit_timer(); } /* Generic SGI handler for (spurious) 8254 interrupts */ diff --git a/arch/mips/sni/time.c b/arch/mips/sni/time.c index 92452d677d8..153f065434e 100644 --- a/arch/mips/sni/time.c +++ b/arch/mips/sni/time.c @@ -2,6 +2,7 @@ #include #include +#include #include #include #include @@ -116,6 +117,8 @@ void __init plat_time_init(void) (int) (r4k_tick % (500000 / HZ))); mips_hpt_frequency = r4k_tick * HZ; + + setup_pit_timer(); } /* diff --git a/include/asm-mips/i8253.h b/include/asm-mips/i8253.h new file mode 100644 index 00000000000..8f689d7df6b --- /dev/null +++ b/include/asm-mips/i8253.h @@ -0,0 +1,30 @@ +/* + * Machine specific IO port address definition for generic. + * Written by Osamu Tomita + */ +#ifndef _MACH_IO_PORTS_H +#define _MACH_IO_PORTS_H + +/* i8253A PIT registers */ +#define PIT_MODE 0x43 +#define PIT_CH0 0x40 +#define PIT_CH2 0x42 + +/* i8259A PIC registers */ +#define PIC_MASTER_CMD 0x20 +#define PIC_MASTER_IMR 0x21 +#define PIC_MASTER_ISR PIC_MASTER_CMD +#define PIC_MASTER_POLL PIC_MASTER_ISR +#define PIC_MASTER_OCW3 PIC_MASTER_ISR +#define PIC_SLAVE_CMD 0xa0 +#define PIC_SLAVE_IMR 0xa1 + +/* i8259A PIC related value */ +#define PIC_CASCADE_IR 2 +#define MASTER_ICW4_DEFAULT 0x01 +#define SLAVE_ICW4_DEFAULT 0x01 +#define PIC_ICW4_AEOI 2 + +extern void setup_pit_timer(void); + +#endif /* !_MACH_IO_PORTS_H */