From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Warren <swarren@wwwdotorg.org>
Date: Mon, 09 Apr 2012 15:09:39 -0600
Subject: [U-Boot] [PATCH v3 10/23] tegra: Add tegra_get_chip_type() to
	detect SKU
In-Reply-To: <1333408743-28720-11-git-send-email-sjg@chromium.org>
References: <1333408743-28720-1-git-send-email-sjg@chromium.org>
	<1333408743-28720-11-git-send-email-sjg@chromium.org>
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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@chromium.org>
> Acked-by: Stephen Warren <swarren@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.