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    SubjectRe: [PATCH v10 17/21] clocksource / arch_timer: Parse GTDT to initialize arch timer
    On Wed, Mar 11, 2015 at 12:39:43PM +0000, Hanjun Guo wrote:
    > Using the information presented by GTDT (Generic Timer Description Table)
    > to initialize the arch timer (not memory-mapped).
    >
    > CC: Daniel Lezcano <daniel.lezcano@linaro.org>
    > CC: Thomas Gleixner <tglx@linutronix.de>
    > Originally-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
    > Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
    > Tested-by: Yijing Wang <wangyijing@huawei.com>
    > Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
    > Tested-by: Jon Masters <jcm@redhat.com>
    > Tested-by: Timur Tabi <timur@codeaurora.org>
    > Tested-by: Robert Richter <rrichter@cavium.com>
    > Acked-by: Robert Richter <rrichter@cavium.com>
    > Reviewed-by: Grant Likely <grant.likely@linaro.org>
    > Signed-off-by: Hanjun Guo <hanjun.guo@linaro.org>
    > ---
    > arch/arm64/kernel/time.c | 7 ++
    > drivers/clocksource/arm_arch_timer.c | 132 ++++++++++++++++++++++++++++-------
    > include/linux/clocksource.h | 6 ++
    > 3 files changed, 118 insertions(+), 27 deletions(-)

    Daniel, can we have your Ack on this patch please? The intention is to
    merge the whole series via the arm64 tree.

    Cheers.

    Will

    > diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
    > index 1a7125c..42f9195 100644
    > --- a/arch/arm64/kernel/time.c
    > +++ b/arch/arm64/kernel/time.c
    > @@ -35,6 +35,7 @@
    > #include <linux/delay.h>
    > #include <linux/clocksource.h>
    > #include <linux/clk-provider.h>
    > +#include <linux/acpi.h>
    >
    > #include <clocksource/arm_arch_timer.h>
    >
    > @@ -72,6 +73,12 @@ void __init time_init(void)
    >
    > tick_setup_hrtimer_broadcast();
    >
    > + /*
    > + * Since ACPI or FDT will only one be available in the system,
    > + * we can use acpi_generic_timer_init() here safely
    > + */
    > + acpi_generic_timer_init();
    > +
    > arch_timer_rate = arch_timer_get_rate();
    > if (!arch_timer_rate)
    > panic("Unable to initialise architected timer.\n");
    > diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
    > index a3025e7..ea62fc7 100644
    > --- a/drivers/clocksource/arm_arch_timer.c
    > +++ b/drivers/clocksource/arm_arch_timer.c
    > @@ -22,6 +22,7 @@
    > #include <linux/io.h>
    > #include <linux/slab.h>
    > #include <linux/sched_clock.h>
    > +#include <linux/acpi.h>
    >
    > #include <asm/arch_timer.h>
    > #include <asm/virt.h>
    > @@ -371,8 +372,12 @@ arch_timer_detect_rate(void __iomem *cntbase, struct device_node *np)
    > if (arch_timer_rate)
    > return;
    >
    > - /* Try to determine the frequency from the device tree or CNTFRQ */
    > - if (of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
    > + /*
    > + * Try to determine the frequency from the device tree or CNTFRQ,
    > + * if ACPI is enabled, get the frequency from CNTFRQ ONLY.
    > + */
    > + if (!acpi_disabled ||
    > + of_property_read_u32(np, "clock-frequency", &arch_timer_rate)) {
    > if (cntbase)
    > arch_timer_rate = readl_relaxed(cntbase + CNTFRQ);
    > else
    > @@ -691,28 +696,8 @@ static void __init arch_timer_common_init(void)
    > arch_timer_arch_init();
    > }
    >
    > -static void __init arch_timer_init(struct device_node *np)
    > +static void __init arch_timer_init(void)
    > {
    > - int i;
    > -
    > - if (arch_timers_present & ARCH_CP15_TIMER) {
    > - pr_warn("arch_timer: multiple nodes in dt, skipping\n");
    > - return;
    > - }
    > -
    > - arch_timers_present |= ARCH_CP15_TIMER;
    > - for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
    > - arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
    > - arch_timer_detect_rate(NULL, np);
    > -
    > - /*
    > - * If we cannot rely on firmware initializing the timer registers then
    > - * we should use the physical timers instead.
    > - */
    > - if (IS_ENABLED(CONFIG_ARM) &&
    > - of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
    > - arch_timer_use_virtual = false;
    > -
    > /*
    > * If HYP mode is available, we know that the physical timer
    > * has been configured to be accessible from PL1. Use it, so
    > @@ -731,13 +716,39 @@ static void __init arch_timer_init(struct device_node *np)
    > }
    > }
    >
    > - arch_timer_c3stop = !of_property_read_bool(np, "always-on");
    > -
    > arch_timer_register();
    > arch_timer_common_init();
    > }
    > -CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_init);
    > -CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_init);
    > +
    > +static void __init arch_timer_of_init(struct device_node *np)
    > +{
    > + int i;
    > +
    > + if (arch_timers_present & ARCH_CP15_TIMER) {
    > + pr_warn("arch_timer: multiple nodes in dt, skipping\n");
    > + return;
    > + }
    > +
    > + arch_timers_present |= ARCH_CP15_TIMER;
    > + for (i = PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++)
    > + arch_timer_ppi[i] = irq_of_parse_and_map(np, i);
    > +
    > + arch_timer_detect_rate(NULL, np);
    > +
    > + arch_timer_c3stop = !of_property_read_bool(np, "always-on");
    > +
    > + /*
    > + * If we cannot rely on firmware initializing the timer registers then
    > + * we should use the physical timers instead.
    > + */
    > + if (IS_ENABLED(CONFIG_ARM) &&
    > + of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
    > + arch_timer_use_virtual = false;
    > +
    > + arch_timer_init();
    > +}
    > +CLOCKSOURCE_OF_DECLARE(armv7_arch_timer, "arm,armv7-timer", arch_timer_of_init);
    > +CLOCKSOURCE_OF_DECLARE(armv8_arch_timer, "arm,armv8-timer", arch_timer_of_init);
    >
    > static void __init arch_timer_mem_init(struct device_node *np)
    > {
    > @@ -804,3 +815,70 @@ static void __init arch_timer_mem_init(struct device_node *np)
    > }
    > CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem",
    > arch_timer_mem_init);
    > +
    > +#ifdef CONFIG_ACPI
    > +static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
    > +{
    > + int trigger, polarity;
    > +
    > + if (!interrupt)
    > + return 0;
    > +
    > + trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
    > + : ACPI_LEVEL_SENSITIVE;
    > +
    > + polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
    > + : ACPI_ACTIVE_HIGH;
    > +
    > + return acpi_register_gsi(NULL, interrupt, trigger, polarity);
    > +}
    > +
    > +/* Initialize per-processor generic timer */
    > +static int __init arch_timer_acpi_init(struct acpi_table_header *table)
    > +{
    > + struct acpi_table_gtdt *gtdt;
    > +
    > + if (arch_timers_present & ARCH_CP15_TIMER) {
    > + pr_warn("arch_timer: already initialized, skipping\n");
    > + return -EINVAL;
    > + }
    > +
    > + gtdt = container_of(table, struct acpi_table_gtdt, header);
    > +
    > + arch_timers_present |= ARCH_CP15_TIMER;
    > +
    > + arch_timer_ppi[PHYS_SECURE_PPI] =
    > + map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
    > + gtdt->secure_el1_flags);
    > +
    > + arch_timer_ppi[PHYS_NONSECURE_PPI] =
    > + map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
    > + gtdt->non_secure_el1_flags);
    > +
    > + arch_timer_ppi[VIRT_PPI] =
    > + map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
    > + gtdt->virtual_timer_flags);
    > +
    > + arch_timer_ppi[HYP_PPI] =
    > + map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
    > + gtdt->non_secure_el2_flags);
    > +
    > + /* Get the frequency from CNTFRQ */
    > + arch_timer_detect_rate(NULL, NULL);
    > +
    > + /* Always-on capability */
    > + arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
    > +
    > + arch_timer_init();
    > + return 0;
    > +}
    > +
    > +/* Initialize all the generic timers presented in GTDT */
    > +void __init acpi_generic_timer_init(void)
    > +{
    > + if (acpi_disabled)
    > + return;
    > +
    > + acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
    > +}
    > +#endif
    > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
    > index 9c78d15..2b2e1f8 100644
    > --- a/include/linux/clocksource.h
    > +++ b/include/linux/clocksource.h
    > @@ -244,4 +244,10 @@ extern void clocksource_of_init(void);
    > static inline void clocksource_of_init(void) {}
    > #endif
    >
    > +#ifdef CONFIG_ACPI
    > +void acpi_generic_timer_init(void);
    > +#else
    > +static inline void acpi_generic_timer_init(void) { }
    > +#endif
    > +
    > #endif /* _LINUX_CLOCKSOURCE_H */
    > --
    > 1.9.1
    >
    >


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