[U-Boot] [PATCH v3 10/23] tegra: Add tegra_get_chip_type() to detect SKU

[Stephen Warren]

On 04/02/2012 05:18 PM, Simon Glass wrote:
> We want to know which type of chip we are running on - the Tegra
> family has several SKUs. This can be determined by reading a
> fuse register, so add this function to ap20.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Acked-by: Stephen Warren <swarren at nvidia.com>
> ---
> Changes in v2:
> - Add check of undocumented values in hidrev register

> diff --git a/arch/arm/cpu/armv7/tegra2/ap20.c b/arch/arm/cpu/armv7/tegra2/ap20.c

> +int tegra_get_chip_type(void)
> +{
> +	struct apb_misc_gp_ctlr *gp;
> +	struct fuse_regs *fuse = (struct fuse_regs *)TEGRA2_FUSE_BASE;
> +	uint tegra_sku_id, rev;
> +
> +	/*
> +	 * This is undocumented, Chip ID is bits 15:8 of the register
> +	 * APB_MISC + 0x804, and has value 0x20 for Tegra20, 0x30 for
> +	 * Tegra30
> +	 */
> +	gp = (struct apb_misc_gp_ctlr *)TEGRA2_APB_MISC_GP_BASE;
> +	rev = (readl(&gp->hidrev) & HIDREV_CHIPID_MASK) >> HIDREV_CHIPID_SHIFT;

That's not entirely true; the register and its fields are documented in
the TRM. The values of the CHIPID field itself are indeed not documented.