Re: [Xen-devel] [PATCH v4 17/21] arm/acpi: Parse GTDT to initialize timer

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Sat, 23 Jan 2016, Shannon Zhao wrote:
> From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> 
> 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: Parth Dixit <parth.dixit@xxxxxxxxxx>
> Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
> ---
> V4: Factor dt parts
> ---
>  xen/arch/arm/time.c | 82 
> ++++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 68 insertions(+), 14 deletions(-)
> 
> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> index 73a1a3e..4261207 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 +66,52 @@ unsigned int timer_get_irq(enum timer_ppi ppi)
>  
>  static __initdata struct dt_device_node *timer;
>  
> +#ifdef CONFIG_ACPI
> +static u32 __init acpi_get_timer_irq_type(u32 flags)
> +{
> +    return (flags & ACPI_GTDT_INTERRUPT_MODE) ? IRQ_TYPE_EDGE_BOTH
> +                                              : IRQ_TYPE_LEVEL_MASK;
> +}
> +
> +/* Initialize per-processor generic timer */
> +static int __init arch_timer_acpi_init(struct acpi_table_header *header)
> +{
> +    u32 irq_type;
> +    struct acpi_table_gtdt *gtdt;
> +
> +    gtdt = container_of(header, struct acpi_table_gtdt, header);
> +
> +    /* Initialize all the generic timer IRQ variable from GTDT table */
> +    irq_type = acpi_get_timer_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_timer_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_timer_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_timer_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;
> +}
> +
> +static void __init preinit_acpi_xen_time(void)
> +{
> +    acpi_table_parse(ACPI_SIG_GTDT, arch_timer_acpi_init);
> +    cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;

I would move this and the other line like this in preinit_dt_xen_time to
preinit_xen_time, with a if (!cpu_khz) check.


> +}
> +#else
> +static inline void preinit_acpi_xen_time(void) { }
> +#endif

As usual, this can go away.

Everything else is good.


>  /* Set up the timer on the boot CPU (early init function) */
> -void __init preinit_xen_time(void)
> +static void __init preinit_dt_xen_time(void)
>  {
>      static const struct dt_device_match timer_ids[] __initconst =
>      {
> @@ -75,6 +120,7 @@ void __init preinit_xen_time(void)
>      };
>      int res;
>      u32 rate;
> +    unsigned int i;
>  
>      timer = dt_find_matching_node(NULL, timer_ids);
>      if ( !timer )
> @@ -82,10 +128,6 @@ void __init preinit_xen_time(void)
>  
>      dt_device_set_used_by(timer, DOMID_XEN);
>  
> -    res = platform_init_time();
> -    if ( res )
> -        panic("Timer: Cannot initialize platform timer");
> -
>      res = dt_property_read_u32(timer, "clock-frequency", &rate);
>      if ( res )
>      {
> @@ -95,15 +137,6 @@ void __init preinit_xen_time(void)
>      else
>          cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
>  
> -    boot_count = READ_SYSREG64(CNTPCT_EL0);
> -}
> -
> -/* Set up the timer on the boot CPU (late init function) */
> -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++ )
>      {
> @@ -113,7 +146,28 @@ int __init init_xen_time(void)
>              panic("Timer: Unable to retrieve IRQ %u from the device tree", 
> i);
>          timer_irq[i] = res;
>      }
> +}
> +
> +void __init preinit_xen_time(void)
> +{
> +    int res;
>  
> +    /* Initialize all the generic timers presented in GTDT */
> +    if ( acpi_disabled )
> +        preinit_dt_xen_time();
> +    else
> +        preinit_acpi_xen_time();
> +
> +    res = platform_init_time();
> +    if ( res )
> +        panic("Timer: Cannot initialize platform timer");
> +
> +    boot_count = READ_SYSREG64(CNTPCT_EL0);
> +}
> +
> +/* Set up the timer on the boot CPU (late init function) */
> +int __init init_xen_time(void)
> +{
>      /* Check that this CPU supports the Generic Timer interface */
>      if ( !cpu_has_gentimer )
>          panic("CPU does not support the Generic Timer v1 interface");
> -- 
> 2.0.4
> 
> 

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