Re: [PATCH v4 3/3] tty: serial: samsung: Fix serial rx on Apple A7-A9

From: Nick Chan
Date: Mon Sep 09 2024 - 23:00:08 EST




On 10/9/2024 09:59, Kwanghoon Son wrote:
> On Mon, 2024-09-09 at 17:51 +0800, Nick Chan wrote:
>>
>> On 9/9/2024 17:43, Kwanghoon Son wrote:
>>> On Mon, 2024-09-09 at 16:37 +0800, Nick Chan wrote:
>>>> Apple's older A7-A9 SoCs seems to use bit 3 in UTRSTAT as RXTO, which is
>>>> enabled by bit 11 in UCON.
>>>>
>>>> Access these bits in addition to the original RXTO and RXTO enable bits,
>>>> to allow serial rx to function on A7-A9 SoCs. This change does not
>>>> appear to affect the A10 SoC and up.
>>>>
>>>> Signed-off-by: Nick Chan <towinchenmi@xxxxxxxxx>
>>>>
>>>
>>> [snip]
>>>
>>>> diff --git a/include/linux/serial_s3c.h b/include/linux/serial_s3c.h
>>>> index 1e8686695487..964a4fbf2626 100644
>>>> --- a/include/linux/serial_s3c.h
>>>> +++ b/include/linux/serial_s3c.h
>>>> @@ -246,24 +246,28 @@
>>>> S5PV210_UFCON_TXTRIG4 | \
>>>> S5PV210_UFCON_RXTRIG4)
>>>>
>>>> -#define APPLE_S5L_UCON_RXTO_ENA 9
>>>> -#define APPLE_S5L_UCON_RXTHRESH_ENA 12
>>>> -#define APPLE_S5L_UCON_TXTHRESH_ENA 13
>>>> -#define APPLE_S5L_UCON_RXTO_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_ENA)
>>>> -#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
>>>> -#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
>>>> +#define APPLE_S5L_UCON_RXTO_ENA 9
>>>> +#define APPLE_S5L_UCON_RXTO_LEGACY_ENA 11
>>>> +#define APPLE_S5L_UCON_RXTHRESH_ENA 12
>>>> +#define APPLE_S5L_UCON_TXTHRESH_ENA 13
>>>> +#define APPLE_S5L_UCON_RXTO_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_ENA)
>>>> +#define APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_LEGACY_ENA)
>>>> +#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
>>>> +#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_TXTHRESH_ENA)
>>>
>>> Small thing, but other diff is not needed except
>>> APPLE_S5L_UCON_RXTO_LEGACY_ENA.
>>>
>>> Kwang.
>> The other diffs are there to keep everything aligned, it looks like a
>> jumbled mess here in the email, but in an editor like nano it is all
>> aligned, before or after this series.
>
> I know why you did. But still there is way keep aligned and only one
> line added.
>
> you just added one more tab to other lines.
> If one tab with APPLE_S5L_UCON_RXTO_LEGACY_ENA, then everything will
> fine.
>
> I think less changes better when see git show or blame.
While as you said, APPLE_S5L_UCON_RXTO_LEGACY_ENA would be fine,
APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK is too long for that to be aligned, see
below without +, - or > distorting everything.

Before:
#define APPLE_S5L_UCON_RXTO_ENA 9
#define APPLE_S5L_UCON_RXTHRESH_ENA 12
#define APPLE_S5L_UCON_TXTHRESH_ENA 13
#define APPLE_S5L_UCON_RXTO_ENA_MSK (1 << APPLE_S5L_UCON_RXTO_ENA)
#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK (1 << APPLE_S5L_UCON_RXTHRESH_ENA)
#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK (1 << APPLE_S5L_UCON_TXTHRESH_ENA)

Patch 1:
#define APPLE_S5L_UCON_RXTO_ENA 9
#define APPLE_S5L_UCON_RXTHRESH_ENA 12
#define APPLE_S5L_UCON_TXTHRESH_ENA 13
#define APPLE_S5L_UCON_RXTO_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_ENA)
#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_TXTHRESH_ENA)

After:
#define APPLE_S5L_UCON_RXTO_ENA 9
#define APPLE_S5L_UCON_RXTO_LEGACY_ENA 11
#define APPLE_S5L_UCON_RXTHRESH_ENA 12
#define APPLE_S5L_UCON_TXTHRESH_ENA 13
#define APPLE_S5L_UCON_RXTO_ENA_MSK BIT(APPLE_S5L_UCON_RXTO_ENA)
#define APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK
BIT(APPLE_S5L_UCON_RXTO_LEGACY_ENA)
#define APPLE_S5L_UCON_RXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_RXTHRESH_ENA)
#define APPLE_S5L_UCON_TXTHRESH_ENA_MSK BIT(APPLE_S5L_UCON_TXTHRESH_ENA)

>
> Best regards,
> Kwang.
>
>>
>>>
>>>>
>>>> #define APPLE_S5L_UCON_DEFAULT (S3C2410_UCON_TXIRQMODE | \
>>>> S3C2410_UCON_RXIRQMODE | \
>>>> S3C2410_UCON_RXFIFO_TOI)
>>>> #define APPLE_S5L_UCON_MASK (APPLE_S5L_UCON_RXTO_ENA_MSK | \
>>>> + APPLE_S5L_UCON_RXTO_LEGACY_ENA_MSK | \
>>>> APPLE_S5L_UCON_RXTHRESH_ENA_MSK | \
>>>> APPLE_S5L_UCON_TXTHRESH_ENA_MSK)
>>>>
>>>> +#define APPLE_S5L_UTRSTAT_RXTO_LEGACY BIT(3)
>>>> #define APPLE_S5L_UTRSTAT_RXTHRESH BIT(4)
>>>> #define APPLE_S5L_UTRSTAT_TXTHRESH BIT(5)
>>>> #define APPLE_S5L_UTRSTAT_RXTO BIT(9)
>>>> -#define APPLE_S5L_UTRSTAT_ALL_FLAGS (0x3f0)
>>>> +#define APPLE_S5L_UTRSTAT_ALL_FLAGS (0x3f8)
>>>>
>>>> #ifndef __ASSEMBLY__
>>>>
>>>
>>
>> Nick Chan
>

Nick Chan