[PATCH linux dev-4.7] arm: aspeed: romulus: Do common setup

[Mine]

Hi Joel,

On Mon, Feb 20, 2017 at 8:15 AM, Joel Stanley <joel at jms.id.au> wrote:
> Hi Lei,
>
> On Sun, Feb 19, 2017 at 12:06 AM, Mine <mine260309 at gmail.com> wrote:
>> I thought do_common_setup() is called by default, but actually it's not.
>> So Romulus needs to call do_common_setup() as well.
>
> We don't need most of what this is doing on any platform.
>
>>        /* Enable LPC FWH cycles, Enable LPC to AHB bridge */
>>        writel(0x00000500, AST_IO(AST_BASE_LPC | 0x80));
>
> This is performed by the LPC driver that Cyril has written.
>
>>        /* Set UART routing */
>>        writel(0x00000000, AST_IO(AST_BASE_LPC | 0x9c));
>
> This is the default. If we need to change it in the future we might
> write a pinmux driver, but for now we could omit this.
>
>>        /* Setup scratch registers */
>>        writel(0x00000042, AST_IO(AST_BASE_LPC | 0x170));
>>        writel(0x00008000, AST_IO(AST_BASE_LPC | 0x174));
>
> We don't have a driver for this. Andrew was thinking about a UIO
> driver. Ben started a discussion[1] upstream about the preferred
> approach.

It means for now they are needed, before the UIO driver is implemented, is it?
So I assume Romulus will need do_common_setup() anyway, at least for
the current kernel.
Otherwise I'm afraid the VUART may not work since it requires register 0x174 to
be set to 0x00008000.

>
> [1] https://lkml.org/lkml/2017/2/17/30
>
> Cheers,
>
> Joel
>
>>
>> --
>> BRs,
>> Lei YU
>>
>> On Sat, Feb 18, 2017 at 9:33 PM, Lei YU <mine260309 at gmail.com> wrote:
>>> Call do_common_setup for romulus.
>>> No other romulus specific setup is needed.
>>> Consider moving do_common_setup() to a common place.
>>>
>>> Signed-off-by: Lei YU <mine260309 at gmail.com>
>>> ---
>>>  arch/arm/mach-aspeed/aspeed.c | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>>
>>> diff --git a/arch/arm/mach-aspeed/aspeed.c b/arch/arm/mach-aspeed/aspeed.c
>>> index 2a11c2e..726b8fa 100644
>>> --- a/arch/arm/mach-aspeed/aspeed.c
>>> +++ b/arch/arm/mach-aspeed/aspeed.c
>>> @@ -218,6 +218,11 @@ static void __init do_witherspoon_setup(void)
>>>         writel(0x68600000, AST_IO(AST_BASE_SPI | 0x30));
>>>  }
>>>
>>> +static void __init do_romulus_setup(void)
>>> +{
>>> +       do_common_setup();
>>> +}
>>> +
>>>  #define SCU_PASSWORD   0x1688A8A8
>>>
>>>  static void __init aspeed_init_early(void)
>>> @@ -253,6 +258,8 @@ static void __init aspeed_init_early(void)
>>>                 do_zaius_setup();
>>>         if (of_machine_is_compatible("ibm,witherspoon-bmc"))
>>>                 do_witherspoon_setup();
>>> +       if (of_machine_is_compatible("ibm,romulus-bmc"))
>>> +               do_romulus_setup();
>>>  }
>>>
>>>  static void __init aspeed_map_io(void)
>>> --
>>> 1.9.1
>>>