Hi Philipp,
On 27 November 2017 at 10:16, Dr. Philipp Tomsich
<philipp.toms...@theobroma-systems.com> wrote:
>
>> On 27 Nov 2017, at 18:10, Simon Glass <s...@chromium.org> wrote:
>>
>> Hi Philipp,
>>
>> On 26 November 2017 at 16:22, Philipp Tomsich
>> <philipp.toms...@theobroma-systems.com> wrote:
>>> The reset circuitry in the RK3399 only resets 'almost all logic' when
>>> a software reset is performed. To make our software maintenance
>>> easier in the future, we want to have the option (controlled by a DTS
>>> property) to force all reset causes other than a power-on reset to
>>> trigger a power-on reset via a GPIO trigger.
>>>
>>> This adds the necessary support to the rk3399-puma (i.e. RK3399-Q7)
>>> board-support and the documentation for the new property
>>> (sysreset-gpio) within the /config-node.
>>>
>>> Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com>
>>> Tested-by: Klaus Goger <klaus.go...@theobroma-systems.com>
>>> ---
>>>
>>> board/theobroma-systems/puma_rk3399/puma-rk3399.c | 46
>>> +++++++++++++++++++++++
>>> doc/device-tree-bindings/config.txt | 6 +++
>>> 2 files changed, 52 insertions(+)
>>
>> Reviewed-by: Simon Glass <s...@chromium.org>
>>
>>>
>>> diff --git a/board/theobroma-systems/puma_rk3399/puma-rk3399.c
>>> b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
>>> index 2b4988e..79dbdf4 100644
>>> --- a/board/theobroma-systems/puma_rk3399/puma-rk3399.c
>>> +++ b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
>>> @@ -9,7 +9,10 @@
>>> #include <misc.h>
>>> #include <dm/pinctrl.h>
>>> #include <dm/uclass-internal.h>
>>> +#include <asm/gpio.h>
>>> #include <asm/setup.h>
>>> +#include <asm/arch/clock.h>
>>> +#include <asm/arch/cru_rk3399.h>
>>> #include <asm/arch/periph.h>
>>> #include <power/regulator.h>
>>> #include <spl.h>
>>> @@ -32,9 +35,52 @@ int board_init(void)
>>> return 0;
>>> }
>>>
>>> +static void rk3399_force_power_on_reset(void)
>>> +{
>>> + ofnode node;
>>> + struct gpio_desc sysreset_gpio;
>>> +
>>> + debug("%s: trying to force a power-on reset\n", __func__);
>>> +
>>> + node = ofnode_path("/config");
>>> + if (!ofnode_valid(node)) {
>>> + debug("%s: no /config node?\n", __func__);
>>> + return;
>>> + }
>>> +
>>> + gpio_request_by_name_nodev(node, "sysreset-gpio", 0,
>>> + &sysreset_gpio, GPIOD_IS_OUT);
>>> +
>>> + if (!dm_gpio_is_valid(&sysreset_gpio)) {
>>
>> If you don't support this GPIO being option, you should check the
>> return value of gpio_request_by_name_nodev() instead. If it is < 0
>> then it did not find a GPIO.
>
> We want to treat this as an option, if either the software stack is known
> to handle partial resets correctly or if the software stack already always
> generates a cold-reset of the entire platform.
OK, so you should be able to do:
if (gpio_request_by_name_nodev(...)) {
debug(...);
return;
}
There is no need to call dm_gpio_is_valid() separately.
>
>>
>>> + debug("%s: could not find a /config/sysreset-gpio\n",
>>> __func__);
>>> + return;
>>> + }
>>> +
>>> + dm_gpio_set_value(&sysreset_gpio, 1);
>>> +}
>>> +
>>> void spl_board_init(void)
>>> {
>>> int ret;
>>> + struct rk3399_cru *cru = rockchip_get_cru();
>>> +
>>> + /*
>>> + * The RK3399 resets only 'almost all logic' (see also in the TRM
>>> + * "3.9.4 Global software reset"), when issuing a software reset.
>>> + * This may cause issues during boot-up for some configurations of
>>> + * the application software stack.
>>> + *
>>> + * To work around this, we test whether the last reset reason was
>>> + * a power-on reset and (if not) issue an overtemp-reset to reset
>>> + * the entire module.
>>> + *
>>> + * While this was previously fixed by modifying the various places
>>> + * that could generate a software reset (e.g. U-Boot's sysreset
>>> + * driver, the ATF or Linux), we now have it here to ensure that
>>> + * we no longer have to track this through the various components.
>>> + */
>>> + if (cru->glb_rst_st != 0)
>>> + rk3399_force_power_on_reset();
>>>
>>> /*
>>> * Turning the eMMC and SPI back on (if disabled via the Qseven
>>> diff --git a/doc/device-tree-bindings/config.txt
>>> b/doc/device-tree-bindings/config.txt
>>> index 15e4349..6cdc16d 100644
>>> --- a/doc/device-tree-bindings/config.txt
>>> +++ b/doc/device-tree-bindings/config.txt
>>> @@ -46,3 +46,9 @@ u-boot,spl-payload-offset
>>> If present (and SPL is controlled by the device-tree), this allows
>>> to override the CONFIG_SYS_SPI_U_BOOT_OFFS setting using a value
>>> from the device-tree.
>>> +
>>> +sysreset-gpio
>>> + If present (and supported by the specific board), indicates a
>>> + GPIO that can be set to trigger a system reset. It is assumed
>>> + that such a system reset will effect a complete platform reset,
>>> + being roughly equivalent to a power-on reset.
>>
>> Is there no kernel binding for this sort of thing?
>
> Not to my knowledge (and grep didn’t find anything either).
>
> Note that the kernel (for ARM64) requests the reset via PSCI (from
> the ATF) and the ATF then needs to do “the right thing”. Many other
> platforms have relied on their watchdog timers to effect a reset in the
> past. So in other words: most of the kernel doesn’t really care about
> a setting like this.
Regards,
Simon
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
