Subject: Re: [PATCH v7 14/50] powerpc/powernv: M64 support on P7IOC

From: Alexey Kardashevskiy <[email-masked]>
Date: Tue, 17 Nov 2015 13:11:56 +1100

On 11/17/2015 12:38 PM, Gavin Shan wrote:
> On Mon, Nov 16, 2015 at 07:02:03PM +1100, Alexey Kardashevskiy wrote:
>> On 11/05/2015 12:12 AM, Gavin Shan wrote:
>>> This enables M64 window on P7IOC, which has been enabled on PHB3.
>>> Different from PHB3 where 16 M64 BARs are supported and each of
>>> them can be owned by one particular PE# exclusively or divided
>>> evenly to 256 segments, every P7IOC PHB has 16 M64 BARs and each
>>> of them are divided to 8 segments. So every P7IOC PHB supports
>>> 128 M64 segments in total. P7IOC has M64DT, which helps mapping
>>> one particular M64 segment# to arbitrary PE#. PHB3 doesn't have
>>> M64DT, indicating that one M64 segment can only be pinned to the
>>> fixed PE#. In order to have same code to support M64 on P7IOC and
>>> PHB3, we just provide 128 M64 segments on every P7IOC PHB and each
>>> of them is pinned to the fixed PE# by bypassing the function of
>>> M64DT. In turn, we just need different phb->init_m64() for P7IOC
>>> and PHB3 to support M64.
>>>
>>> Signed-off-by: Gavin Shan <[email-masked]>
>>> ---
>>>   arch/powerpc/platforms/powernv/pci-ioda.c | 86 +++++++++++++++++++++++++++++--
>>>   arch/powerpc/platforms/powernv/pci.h      |  3 ++
>>>   2 files changed, 86 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>> index 1f7d985..bfe69f1 100644
>>> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>> @@ -256,6 +256,64 @@ static void pnv_ioda_reserve_dev_m64_pe(struct pci_dev *pdev,
>>>   	}
>>>   }
>>>
>>> +static int pnv_ioda1_init_m64(struct pnv_phb *phb)
>>> +{
>>> +	struct resource *r;
>>> +	int index;
>>> +
>>> +	/*
>>> +	 * There are 16 M64 BARs, each of which has 8 segments. So
>>> +	 * there are as many M64 segments as the maximum number of
>>> +	 * PEs, which is 128.
>>> +	 */
>>> +	for (index = 0; index < PNV_IODA1_M64_NUM; index++) {
>>> +		unsigned long base, segsz = phb->ioda.m64_segsize;
>>> +		int64_t rc;
>>> +
>>> +		base = phb->ioda.m64_base +
>>> +		       index * PNV_IODA1_M64_SEGS * segsz;
>>> +		rc = opal_pci_set_phb_mem_window(phb->opal_id,
>>> +				OPAL_M64_WINDOW_TYPE, index, base, 0,
>>> +				PNV_IODA1_M64_SEGS * segsz);
>>> +		if (rc != OPAL_SUCCESS) {
>>> +			pr_warn("  Error %lld setting M64 PHB#%d-BAR#%d\n",
>>> +				rc, phb->hose->global_number, index);
>>> +			goto fail;
>>> +		}
>>> +
>>> +		rc = opal_pci_phb_mmio_enable(phb->opal_id,
>>> +				OPAL_M64_WINDOW_TYPE, index,
>>> +				OPAL_ENABLE_M64_SPLIT);
>>> +		if (rc != OPAL_SUCCESS) {
>>> +			pr_warn("  Error %lld enabling M64 PHB#%d-BAR#%d\n",
>>> +				rc, phb->hose->global_number, index);
>>> +			goto fail;
>>> +		}
>>> +	}
>>> +
>>> +	/*
>>> +	 * Exclude the segment used by the reserved PE, which
>>> +	 * is expected to be 0 or last supported PE#.
>>> +	 */
>>> +	r = &phb->hose->mem_resources[1];
>>
>>
>> What does "1" mean here? A bridge's 64bit prefetchable window?
>>
>
> It's PHB's M64 window.

mem_resources[] of a hose are not windows of the root PCI bridge?

>
>>
>>> +	if (phb->ioda.reserved_pe_idx == 0)
>>> +		r->start += phb->ioda.m64_segsize;
>>> +	else if (phb->ioda.reserved_pe_idx == (phb->ioda.total_pe_num - 1))
>>> +		r->end -= phb->ioda.m64_segsize;
>>> +	else
>>> +		pr_warn("  Cannot cut M64 segment for reserved PE#%d\n",
>>> +			phb->ioda.reserved_pe_idx);
>>> +
>
> Thanks,
> Gavin
>

-- 
Alexey