Re: [PATCH v4 5/5] arm64: dts: Add dts files for Hisilicon Hi6220 SoC

[Bintian <bintian.wang@huawei.com>]

Hello Mark,

On 2015/5/6 11:16, Bintian wrote:
> Hello Mark,
>
> On 2015/5/6 1:13, Mark Rutland wrote:
[...]
>>> +        uart0: uart@f8015000 {    /* console */
>>> +            compatible = "arm,pl011", "arm,primecell";
>>> +            reg = <0x0 0xf8015000 0x0 0x1000>;
>>> +            interrupts = <GIC_SPI 36 IRQ_TYPE_LEVEL_HIGH>;
>>> +            clocks = <&ao_ctrl HI6220_UART0_PCLK>, <&ao_ctrl
>>> HI6220_UART0_PCLK>;
>>> +            clock-names = "uartclk", "apb_pclk";
>>> +        };
>>
>> In a previous discussion [1] the UART on HI6220 was described as not
>> fully PL011 compliant, with a number of differences (e.g. the FIFO
>> length).
>>
>> Given that, I feel somewhat uncomfortable with the current compatible
>> string list. What exactly are those differences? We may need a more
>> specific compatible string (even if in addition to those existing ones),
>> or perhaps other properties.
> The small system can be booted and the console also works well without
> changing any code of driver amba-pl011.c, so I think the compatible
> string is OK for this patch set.
>
> Hisilicon do some performance enhancements based on PL011, but the
> current driver "amba-pl011.c" also works on hi6220 without those
> enhancements driver code.
Checked with Hisilicon chip designer, the UART0 is used for DEBUG
console and compliant with PL011 fully.

Thanks,

Bintian
>
>>
>> Thanks,
>> Mark.
>>
>> [1]
>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/328978.html
>>
>>
>> .
>>
>
>
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