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SubjectRe: [PATCH 1/3] ARM: tegra: Add AHB driver
Date
On Monday 23 April 2012, Hiroshi DOYU wrote:
> The AHB Bus conforms to the AMBA Specification (Rev 2.0) Advanced
> High-performance Bus (AHB) architecture.
>
> Both Tegra20/30 have this.
>
> Signed-off-by: Hiroshi DOYU <hdoyu@nvidia.com>

Please explain in the text above why it's a good idea to have this
driver.


> @@ -122,6 +123,7 @@ void __init tegra20_init_early(void)
> tegra_init_cache(0x331, 0x441);
> tegra_pmc_init();
> tegra_powergate_init();
> + tegra_ahb_gizmo_init();
> }
> #endif
> #ifdef CONFIG_ARCH_TEGRA_3x_SOC
> @@ -132,5 +134,6 @@ void __init tegra30_init_early(void)
> tegra_init_cache(0x441, 0x551);
> tegra_pmc_init();
> tegra_powergate_init();
> + tegra_ahb_gizmo_init();
> }
> #endif

Does it really have to be "early", rather than an initcall? Why?

> +
> +static inline unsigned long gizmo_readl(unsigned long offset)
> +{
> + return readl(IO_TO_VIRT(TEGRA_AHB_GIZMO_BASE + offset));
> +}
> +
> +static inline void gizmo_writel(unsigned long value, unsigned long offset)
> +{
> + writel(value, IO_TO_VIRT(TEGRA_AHB_GIZMO_BASE + offset));
> +}

Please change this to no longer use hardcoded addresses. A good
implementation would scan the device tree for the physical address
and then ioremap the registers in the init function, in order to
save a local __iomem pointer.

Arnd


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