linux-kernel - Re: set rockchip-specific uboot bootmode flags on reboot

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Date:	Thu, 17 Sep 2015 19:07:06 +0800
From:	Andy Yan <andy.yan@...k-chips.com>
To:	Simon Glass <sjg@...omium.org>,
	Heiko Stübner <heiko@...ech.de>
Cc:	linux-rockchip@...ts.infradead.org,
	lk <linux-kernel@...r.kernel.org>,
	lak <linux-arm-kernel@...ts.infradead.org>,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	Olof Johansson <olof@...om.net>, khilman@...aro.org,
	Arnd Bergmann <arnd@...db.de>
Subject: Re: set rockchip-specific uboot bootmode flags on reboot

Hi Heiko:


On 2015年09月10日 02:05, Simon Glass wrote:
> Hi,
>
> On 8 September 2015 at 16:46, Heiko Stübner <heiko@...ech.de> wrote:
>> Hi Andy,
>>
>> Am Dienstag, 8. September 2015, 20:43:07 schrieb Andy Yan:
>>> rockchip platform have a protocol to pass the the kernel
>>> reboot mode to bootloader by some special registers when
>>> system reboot.By this way the bootloader can take different
>>> action according to the different kernel reboot mode, for
>>> example, command "reboot loader" will reboot the board to
>>> rockusb mode, this is a very convenient way to get the board
>>> to download mode.
>>>
>>> Signed-off-by: Andy Yan <andy.yan@...k-chips.com>
>> [...]
>>
>>> @@ -0,0 +1,22 @@
>>> +#ifndef __MACH_ROCKCHIP_LOADER_H
>>> +#define __MACH_ROCKCHIP_LOADER_H
>>> +
>>> +/*high 24 bits is tag, low 8 bits is type*/
>>> +#define SYS_LOADER_REBOOT_FLAG   0x5242C300
>>> +
>>> +enum {
>>> +     BOOT_NORMAL = 0, /* normal boot */
>>> +     BOOT_LOADER,     /* enter loader rockusb mode */
>>> +     BOOT_MASKROM,    /* enter maskrom rockusb mode (not support now) */
>>> +     BOOT_RECOVER,    /* enter recover */
>>> +     BOOT_NORECOVER,  /* do not enter recover */
>>> +     BOOT_SECONDOS,   /* boot second OS (not support now)*/
>>> +     BOOT_WIPEDATA,   /* enter recover and wipe data. */
>>> +     BOOT_WIPEALL,    /* enter recover and wipe all data. */
>>> +     BOOT_CHECKIMG,   /* check firmware img with backup part*/
>>> +     BOOT_FASTBOOT,   /* enter fast boot mode */
>>> +     BOOT_SECUREBOOT_DISABLE,
>>> +     BOOT_CHARGING,   /* enter charge mode */
>>> +     BOOT_MAX         /* MAX VALID BOOT TYPE.*/
>>> +};
>>> +#endif
>> These flags rely on code in the bootloader to actually handle the target
>> action. Nowadays this is uboot, but still a rockchip-specific fork. And we're
>> actively moving away from that, with the recent rk3288 addition to mainline
>> uboot.
>>
>> So unless you convince uboot people that the _underlying special
>> functionality_ behind these flags should be part of uboot, I don't think this
>> is going to fly.
>>
>>
>> In a way this is similar to gpu kernel code talking to proprietary userspace
>> libs - these are also not eligible for the kernel. (meaning stuff like the
>> mali kernel driver not being allowed).
> I don't want to comment on what Linux does or does not want. But I can
> see this sort of feature being useful for devs at least. So long as it
> is defined in a way that is not Rockchip-specific (and the above enum
> looks pretty reasonable on that front, I think it makes sense.
>
> Of course it's a bit odd to target a downstream U-Boot with a Linux
> feature. But hopefully Rockchip's U-Boot support and development will
> move to mainline with time.
    Is there any chance for this patch to be landed?
    As Simon says, it is useful for development. And
    he is upstreaming Rockchip U-boot.
>> [...]
>>
>>> +static int rockchip_reboot_notify(struct notifier_block *this,
>>> +                               unsigned long mode, void *cmd)
>>> +{
>>> +     u32 flag;
>>> +
>>> +     rockchip_get_reboot_flag(cmd, &flag);
>>> +     regmap_write(regmap, flag_reg, flag);
>>> +
>>> +     return NOTIFY_DONE;
>>> +}
>>> +
>>> +static struct notifier_block rockchip_reboot_handler = {
>>> +     .notifier_call = rockchip_reboot_notify,
>>> +     .priority = 150,
>>> +};
>> the restart handlers are meant to really only restart the system, not to
>> execute some actions before the restart happens.
>>
>> See https://lkml.org/lkml/2015/6/3/707 for a similar case.
>>
>>
>> Heiko
> Regards,
> Simon
>
>
>


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