Re: [Xen-devel] [PATCH 5/5] xen/arm: Add OMAP5 architected timer initialization codes.

[Julien Grall <julien.grall@xxxxxxxxxx>]

On 5 August 2013 12:49, Chen Baozi <baozich@xxxxxxxxx> wrote:
> Signed-off-by: Chen Baozi <baozich@xxxxxxxxx>
> ---
>  xen/arch/arm/platforms/omap5.c        | 72 
> +++++++++++++++++++++++++++++++++++
>  xen/arch/arm/time.c                   |  7 +++-
>  xen/include/asm-arm/platforms/omap5.h | 15 ++++++++
>  3 files changed, 93 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/platforms/omap5.c b/xen/arch/arm/platforms/omap5.c
> index eecf35b..568b53d 100644
> --- a/xen/arch/arm/platforms/omap5.c
> +++ b/xen/arch/arm/platforms/omap5.c
> @@ -20,6 +20,77 @@
>  #include <xen/config.h>
>  #include <asm/platforms/omap5.h>
>  #include <asm/platform.h>
> +#include <xen/mm.h>
> +#include <xen/vmap.h>
> +
> +static uint16_t num_den[8][2] = {
> +    {         0,          0 },  /* not used */
> +    {  26 *  64,  26 *  125 },  /* 12.0 Mhz */
> +    {   2 * 768,   2 * 1625 },  /* 13.0 Mhz */
> +    {         0,          0 },  /* not used */
> +    { 130 *   8, 130 *   25 },  /* 19.2 Mhz */
> +    {   2 * 384,   2 * 1625 },  /* 26.0 Mhz */
> +    {   3 * 256,   3 * 1125 },  /* 27.0 Mhz */
> +    { 130 *   4, 130 *   25 },  /* 38.4 Mhz */
> +};
> +
> +/*
> + * The realtime counter also called master counter, is a free-running
> + * counter, which is related to real time. It produces the count used
> + * by the CPU local timer peripherals in teh MPU cluster. The timer counts
> + * at a rate of 6.144 MHz. Because the device operates on different clocks
> + * in different power modes, the master counter shifts operation between
> + * clocks, adjusting the increment per clock in hardware accordingly to
> + * maintain a constant count rate.
> + */
> +static int omap5_init_time(void)
> +{
> +    void __iomem *ckgen_prm_base;
> +    void __iomem *rt_ct_base;
> +    unsigned int sys_clksel;
> +    unsigned int num, den, frac1, frac2;
> +
> +    ckgen_prm_base = ioremap_attr(OMAP5_CKGEN_PRM_BASE,
> +                                  0x20, PAGE_HYPERVISOR_NOCACHE);
> +    if (!ckgen_prm_base) {
> +        dprintk(XENLOG_ERR, "%s: PRM_BASE ioremap failed\n", __func__);
> +        return -ENOMEM;
> +    }
> +
> +    sys_clksel = ioreadl(ckgen_prm_base + OMAP5_CM_CLKSEL_SYS) &
> +        ~SYS_CLKSEL_MASK;
> +
> +    iounmap(ckgen_prm_base);
> +
> +    rt_ct_base = ioremap_attr(REALTIME_COUNTER_BASE,
> +                              0x20, PAGE_HYPERVISOR_NOCACHE);
> +    if (!rt_ct_base) {
> +        dprintk(XENLOG_ERR, "%s: REALTIME_COUNTER_BASE ioremap failed\n", 
> __func__);
> +        return -ENOMEM;
> +    }
> +
> +    frac1 = ioreadl(rt_ct_base + INCREMENTER_NUMERATOR_OFFSET);
> +    num = frac1 & ~NUMERATOR_DENUMERATOR_MASK;
> +    if (num_den[sys_clksel][0] != num) {
> +        frac1 &= NUMERATOR_DENUMERATOR_MASK;
> +        frac1 |= num_den[sys_clksel][0];
> +    }
> +
> +    frac2 = ioreadl(rt_ct_base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET);
> +    den = frac2 & ~NUMERATOR_DENUMERATOR_MASK;
> +    if (num_den[sys_clksel][1] != num) {
> +        frac2 &= NUMERATOR_DENUMERATOR_MASK;
> +        frac2 |= num_den[sys_clksel][1];
> +    }
> +
> +    iowritel(rt_ct_base + INCREMENTER_NUMERATOR_OFFSET, frac1);
> +    iowritel(rt_ct_base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET,
> +             frac2 | PRM_FRAC_INCREMENTER_DENUMERATOR_RELOAD);
> +
> +    iounmap(rt_ct_base);
> +
> +    return 0;
> +}
>
>  static const char const *omap5_dt_compat[] __initdata =
>  {
> @@ -29,6 +100,7 @@ static const char const *omap5_dt_compat[] __initdata =
>
>  PLATFORM_START(omap5, "TI OMAP5")
>      .compatible = omap5_dt_compat,
> +    .init_time = omap5_init_time,
>  PLATFORM_END
>
>  /*
> diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> index 4ed7882..6ca030a 100644
> --- a/xen/arch/arm/time.c
> +++ b/xen/arch/arm/time.c
> @@ -104,6 +104,7 @@ int __init init_xen_time(void)
>      struct dt_device_node *dev;
>      int res;
>      unsigned int i;
> +    const __be32 *rate;
>
>      dev = dt_find_compatible_node(NULL, NULL, "arm,armv7-timer");
>      if ( !dev )
> @@ -134,7 +135,11 @@ int __init init_xen_time(void)
>      if ( !cpu_has_gentimer )
>          panic("CPU does not support the Generic Timer v1 interface.\n");
>
> -    cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
> +    rate = dt_get_property(dev, "clock-frequency", NULL);

You need to check if the length match the size of rate.
Perhaps, you can add an helper dt_property_read_u32 (see
linux/include/linux/of.h).

> +    if (rate)
> +       cpu_khz = be32_to_cpup(rate) / 1000;
> +    else
> +        cpu_khz = READ_SYSREG32(CNTFRQ_EL0) / 1000;
>
>      boot_count = READ_SYSREG64(CNTPCT_EL0);
>      printk("Using generic timer at %lu KHz\n", cpu_khz);
> diff --git a/xen/include/asm-arm/platforms/omap5.h 
> b/xen/include/asm-arm/platforms/omap5.h
> index fa825b7..41d178e 100644
> --- a/xen/include/asm-arm/platforms/omap5.h
> +++ b/xen/include/asm-arm/platforms/omap5.h
> @@ -1,6 +1,21 @@
>  #ifndef __ASM_ARM_PLATFORMS_OMAP5_H
>  #define __ASM_ASM_PLATFORMS_OMAP5_H
>
> +#define REALTIME_COUNTER_BASE                 0x48243200
> +#define INCREMENTER_NUMERATOR_OFFSET          0x10
> +#define INCREMENTER_DENUMERATOR_RELOAD_OFFSET 0x14
> +#define NUMERATOR_DENUMERATOR_MASK            0xfffff000
> +#define PRM_FRAC_INCREMENTER_DENUMERATOR_RELOAD 0x00010000
> +
> +#define OMAP5_L4_WKUP                         0x4AE00000
> +#define OMAP5_PRM_BASE                        (OMAP5_L4_WKUP + 0x6000)
> +#define OMAP5_CKGEN_PRM_BASE                  (OMAP5_PRM_BASE + 0x100)
> +#define OMAP5_CM_CLKSEL_SYS                   0x10
> +#define SYS_CLKSEL_MASK                       0xfffffff8
> +
> +/* Timer's frequency */
> +#define OMAP5_TIMER_FREQUENCY                 6144000 /* 6.144 Mhz*/

Do you use this define somewhere?

-- 
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel