[Xen-devel] [PATCH v3 32/62] arm/acpi: Parse GTDT to initialize timer
Stefano Stabellini
stefano.stabellini at eu.citrix.com
Thu Nov 26 04:54:21 PST 2015
On Tue, 17 Nov 2015, shannon.zhao at linaro.org wrote:
> From: Parth Dixit <parth.dixit at linaro.org>
>
> Parse GTDT (Generic Timer Descriptor Table) to initialize timer. Using
> the information presented by GTDT to initialize the arch timer (not
> memory-mapped).
>
> Signed-off-by: Naresh Bhat <naresh.bhat at linaro.org>
> Signed-off-by: Parth Dixit <parth.dixit at linaro.org>
> Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
> ---
> xen/arch/arm/time.c | 73 +++++++++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 62 insertions(+), 11 deletions(-)
>
> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> index 5ded30c..adbfc2a 100644
> --- a/xen/arch/arm/time.c
> +++ b/xen/arch/arm/time.c
> @@ -29,6 +29,7 @@
> #include <xen/time.h>
> #include <xen/sched.h>
> #include <xen/event.h>
> +#include <xen/acpi.h>
> #include <asm/system.h>
> #include <asm/time.h>
> #include <asm/gic.h>
> @@ -65,8 +66,45 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
>
> static __initdata struct dt_device_node *timer;
>
> +#ifdef CONFIG_ACPI
> +/* Initialize per-processor generic timer */
> +static int __init arch_timer_acpi_init(struct acpi_table_header *table)
> +{
> + unsigned int irq_type;
> + struct acpi_table_gtdt *gtdt;
> +
> + gtdt = container_of(table, struct acpi_table_gtdt, header);
> +
> + /* Initialize all the generic timer IRQ variable from GTDT table */
> + irq_type = acpi_get_irq_type(gtdt->non_secure_el1_flags);
> + irq_set_type(gtdt->non_secure_el1_interrupt, irq_type);
> + timer_irq[TIMER_PHYS_NONSECURE_PPI] = gtdt->non_secure_el1_interrupt;
> +
> + irq_type = acpi_get_irq_type(gtdt->secure_el1_flags);
> + irq_set_type(gtdt->secure_el1_interrupt, irq_type);
> + timer_irq[TIMER_PHYS_SECURE_PPI] = gtdt->secure_el1_interrupt;
> +
> + irq_type = acpi_get_irq_type(gtdt->virtual_timer_flags);
> + irq_set_type(gtdt->virtual_timer_interrupt, irq_type);
> + timer_irq[TIMER_VIRT_PPI] = gtdt->virtual_timer_interrupt;
> +
> + irq_type = acpi_get_irq_type(gtdt->non_secure_el2_flags);
> + irq_set_type(gtdt->non_secure_el2_interrupt, irq_type);
> + timer_irq[TIMER_HYP_PPI] = gtdt->non_secure_el2_interrupt;
> +
> + return 0;
> +}
> +
> +void __init acpi_preinit_xen_time(void)
static?
> +{
> + acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
> +}
> +#else
> +static inline void acpi_preinit_xen_time(void) { }
> +#endif
> +
> /* Set up the timer on the boot CPU (early init function) */
> -void __init preinit_xen_time(void)
> +static void __init dt_preinit_xen_time(void)
> {
> static const struct dt_device_match timer_ids[] __initconst =
> {
> @@ -74,7 +112,6 @@ void __init preinit_xen_time(void)
> { /* sentinel */ },
> };
> int res;
> - u32 rate;
>
> timer = dt_find_matching_node(NULL, timer_ids);
> if ( !timer )
> @@ -86,8 +123,19 @@ void __init preinit_xen_time(void)
> if ( res )
> panic("Timer: Cannot initialize platform timer");
Don't we want to call platform_init_time on ARM too? It doesn't look
like something DT specific. I guess we should move the call to the
generic init function?
> - res = dt_property_read_u32(timer, "clock-frequency", &rate);
> - if ( res )
I think we should keep the clock-frequency DT read in
dt_preinit_xen_time.
> +}
> +
> +void __init preinit_xen_time(void)
> +{
> + u32 rate;
> +
> + /* Initialize all the generic timers presented in GTDT */
> + if ( acpi_disabled )
> + dt_preinit_xen_time();
> + else
> + acpi_preinit_xen_time();
> +
> + if( acpi_disabled && dt_property_read_u32(timer, "clock-frequency", &rate) )
> {
> cpu_khz = rate / 1000;
> timer_dt_clock_frequency = rate;
I don't think we want to read a DT property from a generic
initialization function.
> @@ -104,14 +152,17 @@ int __init init_xen_time(void)
> int res;
> unsigned int i;
>
> - /* Retrieve all IRQs for the timer */
> - for ( i = TIMER_PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++ )
> + if( acpi_disabled )
> {
> - res = platform_get_irq(timer, i);
> -
> - if ( res < 0 )
> - panic("Timer: Unable to retrieve IRQ %u from the device tree", i);
> - timer_irq[i] = res;
> + /* Retrieve all IRQs for the timer */
> + for ( i = TIMER_PHYS_SECURE_PPI; i < MAX_TIMER_PPI; i++ )
> + {
> + res = platform_get_irq(timer, i);
> +
> + if ( res < 0 )
> + panic("Timer: Unable to retrieve IRQ %u from the device tree", i);
> + timer_irq[i] = res;
> + }
> }
Can't be just move this into the DT specific init function?
>
> /* Check that this CPU supports the Generic Timer interface */
> --
> 2.1.0
>
>
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