Re: [PATCH v1 3/3] partitions: Introduce NVIDIA Tegra Partition Table

Stephen Warren
2020-02-25T00:20:11Z

On 2/24/20 4:18 PM, Dmitry Osipenko wrote:
> All NVIDIA Tegra devices use a special partition table format for the
> internal storage partitioning. Most of Tegra devices have GPT partition
> in addition to TegraPT, but some older Android consumer-grade devices do
> not or GPT is placed in a wrong sector, and thus, the TegraPT is needed
> in order to support these devices properly in the upstream kernel. This
> patch adds support for NVIDIA Tegra Partition Table format that is used
> at least by all NVIDIA Tegra20 and Tegra30 devices.

> diff --git a/arch/arm/mach-tegra/tegra.c b/arch/arm/mach-tegra/tegra.c

> +static void __init tegra_boot_config_table_init(void)
> +{
> + void __iomem *bct_base;
> + u16 pt_addr, pt_size;
> +
> + bct_base = IO_ADDRESS(TEGRA_IRAM_BASE) + TEGRA_IRAM_BCT_OFFSET;

This shouldn't be hard-coded. IIRC, the boot ROM writes a BIT (Boot
Information Table) to a fixed location in IRAM, and there's some value
in the BIT that points to where the BCT is in IRAM. In practice, it
might work out that the BCT is always at the same place in IRAM, but
this certainly isn't guaranteed. I think there's code in U-Boot which
extracts the BCT location from the BIT? Yes, see
arch/arm/mach-tegra/ap.c:get_odmdata().