Re: [PATCH v2 1/2] drm/i915: Prepare for multiple GTs

[Abdiel Janulgue <abdiel.janulgue@gmail.com>]

On 14.1.2022 19.59, Andi Shyti wrote:
> Hi Matt,
> 
> [...]
> 
>>> -int intel_uncore_setup_mmio(struct intel_uncore *uncore)
>>> +int intel_uncore_setup_mmio(struct intel_uncore *uncore, phys_addr_t phys_addr)
>>>   {
>>>   	struct drm_i915_private *i915 = uncore->i915;
>>> -	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
>>> -	int mmio_bar;
>>>   	int mmio_size;
>>>   
>>> -	mmio_bar = GRAPHICS_VER(i915) == 2 ? 1 : 0;
>>>   	/*
>>>   	 * Before gen4, the registers and the GTT are behind different BARs.
>>>   	 * However, from gen4 onwards, the registers and the GTT are shared
>>> @@ -2044,7 +2041,7 @@ int intel_uncore_setup_mmio(struct intel_uncore *uncore)
>>>   	else
>>>   		mmio_size = 2 * 1024 * 1024;
>>>   
>>> -	uncore->regs = pci_iomap(pdev, mmio_bar, mmio_size);
>>> +	uncore->regs = ioremap(phys_addr, mmio_size);
>>
>> Is there a specific reason we switch to ioremap() instead of
>> pci_iomap_range()?  I.e., we could pass 'phys_offset' rather than
>> 'phys_addr' and call
>>
>>          pci_iomap_range(pdev, mmio_bar, phys_offset, mmio_size);
>>
>> Not that it really matters too much either way as far as I can see;
>> ioremap()/iounmap() should work fine too.
> 
> this was originally changed by Abdiel (I think) and I left as it
> is as I tried to change as less as I could from the original
> work.

Hey,

It’s been awhile and this code has changed a lot! I remember needing the 
unmapped phys_addr of each tile’s mmio_bar as well when I refactored 
this spot (setup_mmio) so its GGTT portion can be ioremapped according 
to ggtt_probe_common.

Cheers!
Abdiel
> 
>> Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
> 
> Thank you!
> 
> Andi