[U-Boot] [RFC PATCH 1/2] sunxi: retrieve FEL-provided values to environment variables

[Hans de Goede]

Hi,

On 03-09-15 16:11, Bernhard Nortmann wrote:
> This patch extends the misc_init_r() function on sunxi boards
> to test for the presence of a suitable "sunxi" SPL header. If
> found, and the loader ("fel" utility) provided non-zero values
> for either data address or size, then corresponding environment
> variables get set.
>
> misc_init_r() also sets (or clears) the "fel_booted" variable depending
> on the active boot device, using the same logic as spl_boot_device().
>
> The goal is to provide sufficient information (within the U-Boot
> environment) to make intelligent decisions on how to continue the boot
> process, allowing specific customizations for the "FEL boot" case.
>
> Signed-off-by: Bernhard Nortmann <bernhard.nortmann at web.de>
> ---
>
>   board/sunxi/board.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 59 insertions(+)
>
> diff --git a/board/sunxi/board.c b/board/sunxi/board.c
> index 9c855f6..ceab1e0 100644
> --- a/board/sunxi/board.c
> +++ b/board/sunxi/board.c
> @@ -516,6 +516,54 @@ void get_board_serial(struct tag_serialnr *serialnr)
>   }
>   #endif
>
> +#if !defined(CONFIG_SPL_BUILD)
> +static int check_signature(unsigned long io_addr, const char *signature,
> +			   int length)
> +{
> +	do {
> +		if (readb(io_addr) != *signature)
> +			return 0;
> +		io_addr++;
> +		signature++;
> +	} while (--length > 0);
> +	return 1;
> +}
> +
> +#define SPL_SIGNATURE			"SPL" /* marks "sunxi" header */
> +#define SPL_EXPECTED_VERSION		1
> +
> +/*
> + * Check the SPL header for the "sunxi" variant. If found: parse values
> + * that might have been passed by the loader ("fel" utility), and update
> + * the environment accordingly.
> + */
> +static void parse_spl_header(void)
> +{
> +	uint8_t spl_header_version;
> +	uint32_t fel_data_address;
> +	uint32_t fel_data_size;
> +
> +	if (check_signature(0x14, SPL_SIGNATURE, 3)) {
> +		spl_header_version = readb(0x17);
> +		if (spl_header_version == SPL_EXPECTED_VERSION) {
> +			fel_data_address = readl(0x18);
> +			fel_data_size = readl(0x1C);
> +			if (fel_data_address)
> +				setenv_hex("fel_data_addr", fel_data_address);
> +			else
> +				setenv("fel_data_addr", NULL);
> +			if (fel_data_size)
> +				setenv_hex("fel_data_size", fel_data_size);
> +			else
> +				setenv("fel_data_size", NULL);
> +		} else {
> +			printf("sunxi SPL header version mismatch: expected %u, got %u\n",
> +			       SPL_EXPECTED_VERSION, spl_header_version);
> +		}
> +	}
> +}

What if the user interrupts auto-boot with a fel provided boot.scr
and then does "saveenv" ?

Then we end up with a fel_data_addr and fel_data_size permanently
in the env.

At a minimum this function must always do:

setenv("fel_data_addr", NULL);
setenv("fel_data_size", NULL);

(rather then only when we've a spl fel header but no addr / size)

So that we do not end up trying to interpret old values ever.

Ideally though we would find another way not involving putting these
in the environment (not sure if that is easily doable).


> +#endif /* !defined(CONFIG_SPL_BUILD) */
> +
>   #ifdef CONFIG_MISC_INIT_R
>   int misc_init_r(void)
>   {
> @@ -524,6 +572,17 @@ int misc_init_r(void)
>   	uint8_t mac_addr[6];
>   	int ret;
>
> +#if !defined(CONFIG_SPL_BUILD)
> +	/* determine if we are running in FEL mode */
> +	if (readl(4) != 0x4E4F4765 || readl(8) != 0x3054422E) { /* eGON.BT0 */
> +		setenv("fel_booted", "1");
> +		parse_spl_header();
> +	} else {
> +		/* not in FEL mode, delete/clear env var (if present) */
> +		setenv("fel_booted", NULL);

Maybe clear all env variables here?

Or even better clear them all unconditionally, and then set
them when the checks succeed ?


> +	}
> +#endif
> +
>   	ret = sunxi_get_sid(sid);
>   	if (ret == 0 && sid[0] != 0 && sid[3] != 0) {
>   		if (!getenv("ethaddr")) {
>

Regards,

Hans