Commit-ID: ce2e572cfe7b2fc3f0e9da4aa7bc61a2c2c51fc7 Gitweb: http://git.kernel.org/tip/ce2e572cfe7b2fc3f0e9da4aa7bc61a2c2c51fc7 Author: Daniel J Blueman <dan...@numascale.com> AuthorDate: Mon, 21 Sep 2015 18:02:25 +0800 Committer: Thomas Gleixner <t...@linutronix.de> CommitDate: Tue, 22 Sep 2015 22:25:33 +0200
x86/numachip: Introduce Numachip2 timer mechanisms Add 1GHz 64-bit Numachip2 clocksource timer support for accurate system-wide timekeeping, as core TSCs are unsynchronised. Additionally, add a per-core clockevent mechanism that interrupts via the platform IPI vector after a programmed period. [ tglx: Taking it through x86 due to dependencies ] Signed-off-by: Daniel J Blueman <dan...@numascale.com> Acked-by: Steffen Persvold <s...@numascale.com> Cc: Daniel Lezcano <daniel.lezc...@linaro.org> Link: http://lkml.kernel.org/r/1442829745-29311-1-git-send-email-dan...@numascale.com Signed-off-by: Thomas Gleixner <t...@linutronix.de> --- arch/x86/include/asm/numachip/numachip_csr.h | 9 +++ drivers/clocksource/Makefile | 1 + drivers/clocksource/numachip.c | 95 ++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+) diff --git a/arch/x86/include/asm/numachip/numachip_csr.h b/arch/x86/include/asm/numachip/numachip_csr.h index e09d845..29719ee 100644 --- a/arch/x86/include/asm/numachip/numachip_csr.h +++ b/arch/x86/include/asm/numachip/numachip_csr.h @@ -59,6 +59,10 @@ static inline void write_lcsr(unsigned long offset, unsigned int val) #define NUMACHIP2_LCSR_BASE 0xf0000000UL #define NUMACHIP2_LCSR_SIZE 0x1000000UL #define NUMACHIP2_APIC_ICR 0x100000 +#define NUMACHIP2_TIMER_DEADLINE 0x200000 +#define NUMACHIP2_TIMER_INT 0x200008 +#define NUMACHIP2_TIMER_NOW 0x200018 +#define NUMACHIP2_TIMER_RESET 0x200020 static inline void __iomem *numachip2_lcsr_address(unsigned long offset) { @@ -86,4 +90,9 @@ static inline void numachip2_write64_lcsr(unsigned long offset, u64 val) writeq(val, numachip2_lcsr_address(offset)); } +static inline unsigned int numachip2_timer(void) +{ + return (smp_processor_id() % 48) << 6; +} + #endif /* _ASM_X86_NUMACHIP_NUMACHIP_CSR_H */ diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 5c00863..57dfad3 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -62,3 +62,4 @@ obj-$(CONFIG_H8300) += h8300_timer8.o obj-$(CONFIG_H8300_TMR16) += h8300_timer16.o obj-$(CONFIG_H8300_TPU) += h8300_tpu.o obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o +obj-$(CONFIG_X86_NUMACHIP) += numachip.o diff --git a/drivers/clocksource/numachip.c b/drivers/clocksource/numachip.c new file mode 100644 index 0000000..088e5fa --- /dev/null +++ b/drivers/clocksource/numachip.c @@ -0,0 +1,95 @@ +/* + * + * Copyright (C) 2015 Numascale AS. All rights reserved. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/clockchips.h> + +#include <asm/irq.h> +#include <asm/numachip/numachip.h> +#include <asm/numachip/numachip_csr.h> + +static DEFINE_PER_CPU(struct clock_event_device, cpu_ced); + +static cycles_t numachip2_timer_read(struct clocksource *cs) +{ + return numachip2_read64_lcsr(NUMACHIP2_TIMER_NOW); +} + +static struct clocksource numachip2_clocksource = { + .name = "numachip2", + .rating = 295, + .read = numachip2_timer_read, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .mult = 1, + .shift = 0, +}; + +static int numachip2_set_next_event(unsigned long delta, struct clock_event_device *ced) +{ + numachip2_write64_lcsr(NUMACHIP2_TIMER_DEADLINE + numachip2_timer(), + delta); + return 0; +} + +static struct clock_event_device numachip2_clockevent = { + .name = "numachip2", + .rating = 400, + .set_next_event = numachip2_set_next_event, + .features = CLOCK_EVT_FEAT_ONESHOT, + .mult = 1, + .shift = 0, + .min_delta_ns = 1250, + .max_delta_ns = LONG_MAX, +}; + +static void numachip_timer_interrupt(void) +{ + struct clock_event_device *ced = this_cpu_ptr(&cpu_ced); + + ced->event_handler(ced); +} + +static __init void numachip_timer_each(struct work_struct *work) +{ + unsigned local_apicid = __this_cpu_read(x86_cpu_to_apicid) & 0xff; + struct clock_event_device *ced = this_cpu_ptr(&cpu_ced); + + /* Setup IPI vector to local core and relative timing mode */ + numachip2_write64_lcsr(NUMACHIP2_TIMER_INT + numachip2_timer(), + (3 << 22) | (X86_PLATFORM_IPI_VECTOR << 14) | + (local_apicid << 6)); + + *ced = numachip2_clockevent; + ced->cpumask = cpumask_of(smp_processor_id()); + clockevents_register_device(ced); +} + +static int __init numachip_timer_init(void) +{ + if (numachip_system != 2) + return -ENODEV; + + /* Reset timer */ + numachip2_write64_lcsr(NUMACHIP2_TIMER_RESET, 0); + clocksource_register_hz(&numachip2_clocksource, NSEC_PER_SEC); + + /* Setup per-cpu clockevents */ + x86_platform_ipi_callback = numachip_timer_interrupt; + schedule_on_each_cpu(&numachip_timer_each); + + return 0; +} + +arch_initcall(numachip_timer_init); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
