Hello Sascha,
On 4/14/25 13:23, Sascha Hauer wrote:
> On Fri, Apr 11, 2025 at 09:27:47AM +0200, Ahmad Fatoum wrote:
>> Add support for the Linux Automation GmbH Test Automation
>> Controller (TAC). The board boots from eMMC, but requires USB loading if
>> no previous barebox has been put into the eMMC boot partition.
>>
>> Signed-off-by: Leonard Göhrs <l.goe...@pengutronix.de>
>> Signed-off-by: Rouven Czerwinski <r.czerwin...@pengutronix.de>
>> Signed-off-by: Marc Kleine-Budde <m...@pengutronix.de>
>> Signed-off-by: Ahmad Fatoum <a.fat...@pengutronix.de>
[snip]
>> +static const int board_rev_pins[] = {0, 1, 2, 3, 6, 7};
>> +
>> +static u32 get_board_rev(void)
>> +{
>> + u32 board_rev = 0;
>> +
>> + /* Enable GPIOZ bank */
>> + setbits_le32(STM32MP15_RCC_MP_AHB5ENSETR, BIT(0));
>> +
>> + for (size_t i = 0; i < ARRAY_SIZE(board_rev_pins); i++) {
>> + int pin = board_rev_pins[i];
>> +
>> + __stm32_pmx_gpio_input(STM32MP15_GPIOZ_BASE, pin);
>> + board_rev |= __stm32_pmx_gpio_get(STM32MP15_GPIOZ_BASE, pin) <<
>> i;
>> + }
>> +
>> + return board_rev;
>> +}
>
> Is this information available during runtime with some pr_* message or
> variable?
No. There is more extensive board revision information in the EEPROM
though, which is indeed available at runtime via the separately
submitted TLV series.
>> +static void noinline select_fdt_and_start(void *fdt)
>> +{
>> + putc_ll('>');
>> +
>> + switch (get_board_rev()) {
>> + case BOARD_GEN1:
>> + fdt = runtime_address(__dtb_z_stm32mp157c_lxa_tac_gen1_start);
>> + break;
>> + case BOARD_GEN2:
>> + fdt = runtime_address(__dtb_z_stm32mp157c_lxa_tac_gen2_start);
>> + break;
>> + case BOARD_GEN3:
>> + fdt = runtime_address(__dtb_z_stm32mp153c_lxa_tac_gen3_start);
>> + break;
>> + }
>
> This check only matches for minor revision 0. Shouldn't the minor
> version rather be ignored here?
I am not sure if a generation is always equal to the major version - 1.
It seems we have no minor revisions != 0 in the field.
If Leonard (Cc'd) doesn't object, I'll mask away the lower 2 bits for v2.
>> +ENTRY_FUNCTION(start_stm32mp15xc_lxa_tac, r0, r1, r2)
>> +{
>> + stm32mp_cpu_lowlevel_init();
>> +
>> + /*
>> + * stm32mp_cpu_lowlevel_init sets up a stack. Do the remaining
>> + * init in a non-naked function. Register r2 points to the fdt
>> + * from the FIT image which can be used as a default.
>> + */
>
> "the fdt from the FIT image" seems to imply that this entry is only used
> as a 2nd state entry, but it's used as a 1st stage entry as well, isn't
> it?
s/FIT/FIP. First stage bootloader is TF-A.
> I would rephrase that to something like "in case of a 2nd stage boot r2
> points to the fdt..."
There is no first stage boot.
Cheers,
Ahmad
>
> Sascha
>
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