Re: [PATCH] OMAP35x: Add support for 720MHz part

[Tony Lindgren <tony@atomide.com>]

Hi,

* Sanjeev Premi <premi@ti.com> [091012 06:00]:
> This patch adds support for ARM running at 720MHz part.
> 
> The 720MHz capability can be probed run-time by reading the
> PRODID.SKUID[3:0] at 0x4830A20C.
> 
>   [1] http://focus.ti.com/lit/ug/spruff1d/spruff1d.pdf
> 
> Signed-off-by: Sanjeev Premi <premi@ti.com>
> ---
>  arch/arm/mach-omap2/clock34xx.c           |    6 ++++++
>  arch/arm/mach-omap2/id.c                  |   11 +++++++++++
>  arch/arm/plat-omap/include/mach/control.h |    7 +++++++
>  arch/arm/plat-omap/include/mach/cpu.h     |    2 ++
>  4 files changed, 26 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c
> index 489556e..9b56af3 100644
> --- a/arch/arm/mach-omap2/clock34xx.c
> +++ b/arch/arm/mach-omap2/clock34xx.c
> @@ -1096,6 +1096,12 @@ static int __init omap2_clk_arch_init(void)
>  	if (!mpurate)
>  		return -EINVAL;
>  
> +	if ((mpurate == 720000000) && !omap3_has_720mhz()) {
> +		printk(KERN_ERR "*** Silicon doesn't support 720MHz\n");
> +
> +		mpurate = 600000000;  /* Set to highest supported */
> +	}
> +
>  	/* REVISIT: not yet ready for 343x */
>  	if (clk_set_rate(&dpll1_ck, mpurate))
>  		printk(KERN_ERR "*** Unable to set MPU rate\n");

To me it seems like this should be limited in clk_set_rate()
instead.


> diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
> index d4d563b..e0b427a 100644
> --- a/arch/arm/mach-omap2/id.c
> +++ b/arch/arm/mach-omap2/id.c
> @@ -79,6 +79,7 @@ EXPORT_SYMBOL(omap_type);
>  #define OMAP_TAP_DIE_ID_2	0x0220
>  #define OMAP_TAP_DIE_ID_3	0x0224
>  
> +
>  #define read_tap_reg(reg)	__raw_readl(tap_base  + (reg))
>  
>  struct omap_id {
> @@ -180,6 +181,15 @@ void __init omap3_check_features(void)
>  	 * TODO: Get additional info (where applicable)
>  	 *       e.g. Size of L2 cache.
>  	 */
> +
> +	/*
> +	 * Does it support 720MHz?
> +	 */
> +	status = (OMAP3_SKUID_MASK & read_tap_reg(OMAP3_PRODID));
> +
> +	if (status & OMAP3_SKUID_720MHZ) {
> +		omap3_features |= OMAP3_HAS_720MHZ;
> +	}
>  }
>  
>  void __init omap3_check_revision(void)

How would 720MHz speed be any different from other speeds?


> @@ -296,6 +306,7 @@ void __init omap3_cpuinfo(void)
>  	OMAP3_SHOW_FEATURE(sgx);
>  	OMAP3_SHOW_FEATURE(neon);
>  	OMAP3_SHOW_FEATURE(isp);
> +	OMAP3_SHOW_FEATURE(720mhz);
>  }
>  
>  /*
> diff --git a/arch/arm/plat-omap/include/mach/control.h b/arch/arm/plat-omap/include/mach/control.h
> index fdb6300..e886bb6 100644
> --- a/arch/arm/plat-omap/include/mach/control.h
> +++ b/arch/arm/plat-omap/include/mach/control.h
> @@ -238,6 +238,13 @@
>  #define		FEAT_NEON		0
>  #define		FEAT_NEON_NONE		1
>  
> +/*
> + * Product ID register
> + */
> +#define OMAP3_PRODID			0x020C
> +
> +#define OMAP3_SKUID_MASK		0x0f
> +#define 	OMAP3_SKUID_720MHZ	0x08
>  
>  #ifndef __ASSEMBLY__
>  #if defined(CONFIG_ARCH_OMAP2) || defined(CONFIG_ARCH_OMAP3) || \
> diff --git a/arch/arm/plat-omap/include/mach/cpu.h b/arch/arm/plat-omap/include/mach/cpu.h
> index 8d0841b..12b91f7 100644
> --- a/arch/arm/plat-omap/include/mach/cpu.h
> +++ b/arch/arm/plat-omap/include/mach/cpu.h
> @@ -472,6 +472,7 @@ extern u32 omap3_features;
>  #define OMAP3_HAS_SGX			BIT(2)
>  #define OMAP3_HAS_NEON			BIT(3)
>  #define OMAP3_HAS_ISP			BIT(4)
> +#define OMAP3_HAS_720MHZ		BIT(5)
>  
>  #define OMAP3_HAS_FEATURE(feat,flag)			\
>  static inline unsigned int omap3_has_ ##feat(void)	\
> @@ -484,5 +485,6 @@ OMAP3_HAS_FEATURE(sgx, SGX)
>  OMAP3_HAS_FEATURE(iva, IVA)
>  OMAP3_HAS_FEATURE(neon, NEON)
>  OMAP3_HAS_FEATURE(isp, ISP)
> +OMAP3_HAS_FEATURE(720mhz, 720MHZ)
>  
>  #endif

I think we should rather implement a function omap_get_max_rate()
or similar, and then the clock framework initializes the clocks
based on that. This way clk_set_rate() can limit the speed
as needed.

Regards,

Tony