diff options
Diffstat (limited to 'arch/mn10300/kernel')
| -rw-r--r-- | arch/mn10300/kernel/irq.c | 71 | ||||
| -rw-r--r-- | arch/mn10300/kernel/time.c | 52 |
2 files changed, 86 insertions, 37 deletions
diff --git a/arch/mn10300/kernel/irq.c b/arch/mn10300/kernel/irq.c index 761c434a248..56c64ccc9c2 100644 --- a/arch/mn10300/kernel/irq.c +++ b/arch/mn10300/kernel/irq.c @@ -20,22 +20,8 @@ EXPORT_SYMBOL(__mn10300_irq_enabled_epsw); atomic_t irq_err_count; /* - * MN10300 INTC controller operations + * MN10300 interrupt controller operations */ -static void mn10300_cpupic_disable(unsigned int irq) -{ - u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_DETECT; - tmp = GxICR(irq); -} - -static void mn10300_cpupic_enable(unsigned int irq) -{ - u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; - tmp = GxICR(irq); -} - static void mn10300_cpupic_ack(unsigned int irq) { u16 tmp; @@ -60,26 +46,54 @@ static void mn10300_cpupic_mask_ack(unsigned int irq) static void mn10300_cpupic_unmask(unsigned int irq) { u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT; + GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; tmp = GxICR(irq); } -static void mn10300_cpupic_end(unsigned int irq) +static void mn10300_cpupic_unmask_clear(unsigned int irq) { + /* the MN10300 PIC latches its interrupt request bit, even after the + * device has ceased to assert its interrupt line and the interrupt + * channel has been disabled in the PIC, so for level-triggered + * interrupts we need to clear the request bit when we re-enable */ u16 tmp = GxICR(irq); - GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE; + GxICR(irq) = (tmp & GxICR_LEVEL) | GxICR_ENABLE | GxICR_DETECT; tmp = GxICR(irq); } -static struct irq_chip mn10300_cpu_pic = { - .name = "cpu", - .disable = mn10300_cpupic_disable, - .enable = mn10300_cpupic_enable, +/* + * MN10300 PIC level-triggered IRQ handling. + * + * The PIC has no 'ACK' function per se. It is possible to clear individual + * channel latches, but each latch relatches whether or not the channel is + * masked, so we need to clear the latch when we unmask the channel. + * + * Also for this reason, we don't supply an ack() op (it's unused anyway if + * mask_ack() is provided), and mask_ack() just masks. + */ +static struct irq_chip mn10300_cpu_pic_level = { + .name = "cpu_l", + .disable = mn10300_cpupic_mask, + .enable = mn10300_cpupic_unmask_clear, + .ack = NULL, + .mask = mn10300_cpupic_mask, + .mask_ack = mn10300_cpupic_mask, + .unmask = mn10300_cpupic_unmask_clear, +}; + +/* + * MN10300 PIC edge-triggered IRQ handling. + * + * We use the latch clearing function of the PIC as the 'ACK' function. + */ +static struct irq_chip mn10300_cpu_pic_edge = { + .name = "cpu_e", + .disable = mn10300_cpupic_mask, + .enable = mn10300_cpupic_unmask, .ack = mn10300_cpupic_ack, .mask = mn10300_cpupic_mask, .mask_ack = mn10300_cpupic_mask_ack, .unmask = mn10300_cpupic_unmask, - .end = mn10300_cpupic_end, }; /* @@ -114,7 +128,8 @@ void set_intr_level(int irq, u16 level) */ void set_intr_postackable(int irq) { - set_irq_handler(irq, handle_level_irq); + set_irq_chip_and_handler(irq, &mn10300_cpu_pic_level, + handle_level_irq); } /* @@ -126,8 +141,12 @@ void __init init_IRQ(void) for (irq = 0; irq < NR_IRQS; irq++) if (irq_desc[irq].chip == &no_irq_type) - set_irq_chip_and_handler(irq, &mn10300_cpu_pic, - handle_edge_irq); + /* due to the PIC latching interrupt requests, even + * when the IRQ is disabled, IRQ_PENDING is superfluous + * and we can use handle_level_irq() for edge-triggered + * interrupts */ + set_irq_chip_and_handler(irq, &mn10300_cpu_pic_edge, + handle_level_irq); unit_init_IRQ(); } diff --git a/arch/mn10300/kernel/time.c b/arch/mn10300/kernel/time.c index babb7c2ac37..e4606586f94 100644 --- a/arch/mn10300/kernel/time.c +++ b/arch/mn10300/kernel/time.c @@ -1,6 +1,6 @@ /* MN10300 Low level time management * - * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. + * Copyright (C) 2007-2008 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - Derived from arch/i386/kernel/time.c * @@ -16,6 +16,7 @@ #include <linux/init.h> #include <linux/smp.h> #include <linux/profile.h> +#include <linux/cnt32_to_63.h> #include <asm/irq.h> #include <asm/div64.h> #include <asm/processor.h> @@ -40,27 +41,54 @@ static struct irqaction timer_irq = { .name = "timer", }; +static unsigned long sched_clock_multiplier; + /* * scheduler clock - returns current time in nanosec units. */ unsigned long long sched_clock(void) { union { - unsigned long long l; - u32 w[2]; - } quot; + unsigned long long ll; + unsigned l[2]; + } tsc64, result; + unsigned long tsc, tmp; + unsigned product[3]; /* 96-bit intermediate value */ + + /* read the TSC value + */ + tsc = 0 - get_cycles(); /* get_cycles() counts down */ - quot.w[0] = mn10300_last_tsc - get_cycles(); - quot.w[1] = 1000000000; + /* expand to 64-bits. + * - sched_clock() must be called once a minute or better or the + * following will go horribly wrong - see cnt32_to_63() + */ + tsc64.ll = cnt32_to_63(tsc) & 0x7fffffffffffffffULL; - asm("mulu %2,%3,%0,%1" - : "=r"(quot.w[1]), "=r"(quot.w[0]) - : "0"(quot.w[1]), "1"(quot.w[0]) + /* scale the 64-bit TSC value to a nanosecond value via a 96-bit + * intermediate + */ + asm("mulu %2,%0,%3,%0 \n" /* LSW * mult -> 0:%3:%0 */ + "mulu %2,%1,%2,%1 \n" /* MSW * mult -> %2:%1:0 */ + "add %3,%1 \n" + "addc 0,%2 \n" /* result in %2:%1:%0 */ + : "=r"(product[0]), "=r"(product[1]), "=r"(product[2]), "=r"(tmp) + : "0"(tsc64.l[0]), "1"(tsc64.l[1]), "2"(sched_clock_multiplier) : "cc"); - do_div(quot.l, MN10300_TSCCLK); + result.l[0] = product[1] << 16 | product[0] >> 16; + result.l[1] = product[2] << 16 | product[1] >> 16; - return quot.l; + return result.ll; +} + +/* + * initialise the scheduler clock + */ +static void __init mn10300_sched_clock_init(void) +{ + sched_clock_multiplier = + __muldiv64u(NSEC_PER_SEC, 1 << 16, MN10300_TSCCLK); } /* @@ -128,4 +156,6 @@ void __init time_init(void) /* start the watchdog timer */ watchdog_go(); #endif + + mn10300_sched_clock_init(); } |