Re: [PATCH v2 1/2] xen/arm64: Add Support for Allwinner H5 (sun50i)

[Julien Grall <julien.grall@arm.com>]

On 28/09/17 23:49, Andre Przywara wrote:
> Hi,

Hi,

> On 09/28/2017 01:03 PM, Julien Grall wrote:
>>
>>>   #define SUNXI_WDT_MODE            0x04
>>> -#define SUNXI_WDT_MODEADDR        (SUNXI_WDT_BASE + SUNXI_WDT_MODE)
>>>   #define SUNXI_WDT_MODE_EN         (1 << 0)
>>>   #define SUNXI_WDT_MODE_RST_EN     (1 << 1)
>>> -static void sunxi_reset(void)
>>> +static void sunxi_reset(u32 base)
>>>   {
>>>       void __iomem *wdt;
>>> -    wdt = ioremap_nocache(SUNXI_WDT_MODEADDR & PAGE_MASK, PAGE_SIZE);
>>> +    wdt = ioremap_nocache((base + SUNXI_WDT_MODE) & PAGE_MASK, 
>>> PAGE_SIZE);
>>>       if ( !wdt )
>>>       {
>>>           dprintk(XENLOG_ERR, "Unable to map watchdog register!\n");
>>> @@ -42,19 +42,35 @@ static void sunxi_reset(void)
>>>       /* Enable watchdog to trigger a reset after 500 ms: */
>>>       writel(SUNXI_WDT_MODE_EN | SUNXI_WDT_MODE_RST_EN,
>>> -      wdt + (SUNXI_WDT_MODEADDR & ~PAGE_MASK));
>>> +      wdt + ((base + SUNXI_WDT_MODE) & ~PAGE_MASK));
>>>       iounmap(wdt); >
>>>       for (;;)
>>>           wfi();
>>>   }
>>>
>>> -static const char * const sunxi_dt_compat[] __initconst =
>>> +static void sunxi_a20_reset(void)
>>> +{
>>> +    sunxi_reset(SUNXI_WDT_A20_BASE);
>>> +}
>>> +
>>> +static void sunxi_h5_reset(void)
>>> +{
>>> +    sunxi_reset(SUNXI_WDT_H5_BASE);
>>
>> If I read correctly the Device-Tree for 
>> (linux/arch/arm64/boot/dts/allwinner/sun50i-h5.dtsi), the firmware is 
>> supporting PSCI 0.2.
>>
>> PSCI 0.2 provides call for power-off/reset, so implementation the 
>> reset callback should not be necessary.
> 
> Yes, indeed, on the H5 PSCI 0.2 reset works via ATF.
> 
>> Similarly the cubietrucks we have in osstest are using PSCI 0.2 and 
>> should not need the reset. Andre do you know if it is the case for all 
>> the A20?
> 
> It claims 0.2, but in fact it seems not to be fully compliant, as (from 
> looking at the code) U-Boot lacks the reset and poweroff calls. But it 
> looks rather straight-forward to add them, as U-Boot knows how to reset 
> and one would just need to wire up psci_system_reset to this.

Hmmm ok :/. Please ignore my suggestion below to drop reset callback for 
all the allwinner platforms.

Cheers,

-- 
Julien Grall

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