Hi Andre Przywara:
I can understand the motivation behind this patch, which
I think it's a good addition to BROM FEL mode..
On 00:59 Wed 09 Apr , Andre Przywara wrote:
> Some boards with Allwinner SoCs feature a "FEL" key, sometimes also
> labelled "uboot", which triggers the BootROM FEL mode, when pressed upon
> power-on or reset. This allows to access the SoC's memory via USB OTG,
> and to upload and execute code. There is a tool to upload our U-Boot image
> and immediately boot it, when the SoC is in FEL mode.
>
> To mimic this convenient behaviour on boards without such a dedicated key,
> we can query a GPIO pin very early in the SPL boot, then trigger the
> BootROM FEL routine. There has not been much of a SoC or board setup at
> this point, so we enter the BROM in a rather pristine state still. On
> 64-bit SoCs the required AArch32 reset guarantees a clean CPU state anyway.
>
> Any GPIO can be used for that, and a board (or a user) is expected to
> specify the GPIO name using the CONFIG_SUNXI_FAKE_FEL_PIN Kconfig variable.
> When this variable is not set, the compiler will optimise away the call.
>
is it possible to provide a dts interface to specify the gpio pin?
it would be more convenient, but a CONFIG option would be fine..
> Call the code first thing in board_init_f(), which is the first sunxi
> specific C routine.
>
> Signed-off-by: Andre Przywara <andre.przyw...@arm.com>
> ---
> arch/arm/mach-sunxi/Kconfig | 9 +++++++++
> arch/arm/mach-sunxi/board.c | 30 ++++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+)
>
> diff --git a/arch/arm/mach-sunxi/Kconfig b/arch/arm/mach-sunxi/Kconfig
> index 25b47ada7ad..912d3a3a650 100644
> --- a/arch/arm/mach-sunxi/Kconfig
> +++ b/arch/arm/mach-sunxi/Kconfig
> @@ -789,6 +789,15 @@ config MMC_SUNXI_SLOT_EXTRA
> slot or emmc on mmc1 - mmc3. Setting this to 1, 2 or 3 will enable
> support for this.
>
> +config SUNXI_FAKE_FEL_PIN
> + string "fake FEL GPIO pin"
> + default ""
> + ---help---
> + Define a GPIO that shall force entering FEL mode when a button
> + connected to this pin is pressed at boot time.
> + This takes a string in the format understood by sunxi_name_to_gpio,
> + e.g. PH1 for pin 1 of port H.
> +
> config I2C0_ENABLE
> bool "Enable I2C/TWI controller 0"
> default y if MACH_SUN4I || MACH_SUN5I || MACH_SUN7I || MACH_SUN8I_R40
> diff --git a/arch/arm/mach-sunxi/board.c b/arch/arm/mach-sunxi/board.c
> index 701899ee4b2..ea0e7bb381d 100644
> --- a/arch/arm/mach-sunxi/board.c
> +++ b/arch/arm/mach-sunxi/board.c
> @@ -457,8 +457,38 @@ u32 spl_mmc_boot_mode(struct mmc *mmc, const u32
> boot_device)
> return result;
> }
>
> +static void check_fake_fel_button(void)
> +{
> + u32 brom_entry = 0x20;
> + int pin, value, mux;
> +
> + /* check for empty string at compile time */
> + if (sizeof(CONFIG_SUNXI_FAKE_FEL_PIN) == sizeof(""))
> + return;
> +
> + pin = sunxi_name_to_gpio(CONFIG_SUNXI_FAKE_FEL_PIN);
> + if (pin < 0)
> + return;
> +
> + mux = sunxi_gpio_get_cfgpin(pin);
> + sunxi_gpio_set_cfgpin(pin, SUNXI_GPIO_INPUT);
> + value = gpio_get_value(pin);
> + sunxi_gpio_set_cfgpin(pin, mux);
> +
> + if (value)
> + return;
so will skip EFL mode when "GPIO == 1" (which means gpio high level)?
maybe we should document in the Kconfig help section:
setting GPIO low to enter FEL mode
or even great if the gpio can be configurable for FEL mode
> +
> + /* Older SoCs maps the BootROM high in the address space. */
> + if (fel_stash.sctlr & BIT(13))
> + brom_entry |= 0xffff0000;
> +
> + return_to_fel(0, brom_entry);
> +}
> +
> void board_init_f(ulong dummy)
> {
> + check_fake_fel_button();
> +
> sunxi_sram_init();
>
> /* Enable non-secure access to some peripherals */
> --
> 2.46.3
>
--
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55
