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author | Raghu Gandham <Raghu.Gandham@imgtec.com> | 2013-04-10 23:30:12 +0200 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2013-05-09 17:55:21 +0200 |
commit | 0ab2b7d08ea7226dc72ff0f8c05f470566facf7c (patch) | |
tree | 7b791c6907a47733b1256da5e20600d182b36d40 /arch/mips/kernel/cevt-gic.c | |
parent | MIPS: Formatting clean-ups for clocksources. (diff) | |
download | linux-0ab2b7d08ea7226dc72ff0f8c05f470566facf7c.tar.xz linux-0ab2b7d08ea7226dc72ff0f8c05f470566facf7c.zip |
MIPS: Add new GIC clockevent driver.
Add new clockevent driver that uses the counter present on the MIPS
Global Interrupt Controller.
Signed-off-by: Raghu Gandham <Raghu.Gandham@imgtec.com>
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
Diffstat (limited to 'arch/mips/kernel/cevt-gic.c')
-rw-r--r-- | arch/mips/kernel/cevt-gic.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/mips/kernel/cevt-gic.c b/arch/mips/kernel/cevt-gic.c new file mode 100644 index 000000000000..730eaf92c018 --- /dev/null +++ b/arch/mips/kernel/cevt-gic.c @@ -0,0 +1,104 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2013 Imagination Technologies Ltd. + */ +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/percpu.h> +#include <linux/smp.h> +#include <linux/irq.h> + +#include <asm/time.h> +#include <asm/gic.h> +#include <asm/mips-boards/maltaint.h> + +DEFINE_PER_CPU(struct clock_event_device, gic_clockevent_device); +int gic_timer_irq_installed; + + +static int gic_next_event(unsigned long delta, struct clock_event_device *evt) +{ + u64 cnt; + int res; + + cnt = gic_read_count(); + cnt += (u64)delta; + gic_write_compare(cnt); + res = ((int)(gic_read_count() - cnt) >= 0) ? -ETIME : 0; + return res; +} + +void gic_set_clock_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + /* Nothing to do ... */ +} + +irqreturn_t gic_compare_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *cd; + int cpu = smp_processor_id(); + + gic_write_compare(gic_read_compare()); + cd = &per_cpu(gic_clockevent_device, cpu); + cd->event_handler(cd); + return IRQ_HANDLED; +} + +struct irqaction gic_compare_irqaction = { + .handler = gic_compare_interrupt, + .flags = IRQF_PERCPU | IRQF_TIMER, + .name = "timer", +}; + + +void gic_event_handler(struct clock_event_device *dev) +{ +} + +int __cpuinit gic_clockevent_init(void) +{ + unsigned int cpu = smp_processor_id(); + struct clock_event_device *cd; + unsigned int irq; + + if (!cpu_has_counter || !gic_frequency) + return -ENXIO; + + irq = MIPS_GIC_IRQ_BASE; + + cd = &per_cpu(gic_clockevent_device, cpu); + + cd->name = "MIPS GIC"; + cd->features = CLOCK_EVT_FEAT_ONESHOT; + + clockevent_set_clock(cd, gic_frequency); + + /* Calculate the min / max delta */ + cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); + cd->min_delta_ns = clockevent_delta2ns(0x300, cd); + + cd->rating = 300; + cd->irq = irq; + cd->cpumask = cpumask_of(cpu); + cd->set_next_event = gic_next_event; + cd->set_mode = gic_set_clock_mode; + cd->event_handler = gic_event_handler; + + clockevents_register_device(cd); + + GICWRITE(GIC_REG(VPE_LOCAL, GIC_VPE_COMPARE_MAP), 0x80000002); + GICWRITE(GIC_REG(VPE_LOCAL, GIC_VPE_SMASK), GIC_VPE_SMASK_CMP_MSK); + + if (gic_timer_irq_installed) + return 0; + + gic_timer_irq_installed = 1; + + setup_irq(irq, &gic_compare_irqaction); + irq_set_handler(irq, handle_percpu_irq); + return 0; +} |