Re: [PATCH v7 25/50] powerpc/powernv: Reserve PE for root bus

Gavin Shan
2015-11-17T09:07:48Z

On Tue, Nov 17, 2015 at 05:04:42PM +1100, Alexey Kardashevskiy wrote:
>On 11/05/2015 12:12 AM, Gavin Shan wrote:
>>We're going to reserve/assign PEs when pcibios_setup_bridge() is
>>called. The function won't be called for root bus as it doesn't
>>have parent bridge. However, the root bus still needs a PE to be
>>covered.
>>
>>This reserves PE numbers that are adjacent to the reserved one
>>for root buses.
>
>
>Somewhere in the patchset you need to describe why you need a separate PE for
>a root bus and why reserved_pe_idx is not enough for this.
>

Please confirm if it's fine to add the descrption in this patch's chagelog.

>
>>
>>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>---
>> arch/powerpc/platforms/powernv/pci-ioda.c | 33 ++++++++++++++++++++++---------
>> arch/powerpc/platforms/powernv/pci.h | 1 +
>> 2 files changed, 25 insertions(+), 9 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index eea1c96..5e6745f 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -207,14 +207,14 @@ static int pnv_ioda2_init_m64(struct pnv_phb *phb)
>> set_bit(phb->ioda.m64_bar_idx, &phb->ioda.m64_bar_alloc);
>>
>> /*
>>- * Strip off the segment used by the reserved PE, which is
>>- * expected to be 0 or last one of PE capabicity.
>>+ * Exclude the segments for reserved and root bus PE, which
>>+ * are first or last two PEs.
>> */
>> r = &phb->hose->mem_resources[1];
>> if (phb->ioda.reserved_pe_idx == 0)
>>- r->start += phb->ioda.m64_segsize;
>>+ r->start += (2 * phb->ioda.m64_segsize);
>> else if (phb->ioda.reserved_pe_idx == (phb->ioda.total_pe_num - 1))
>>- r->end -= phb->ioda.m64_segsize;
>>+ r->end -= (2 * phb->ioda.m64_segsize);
>> else
>> pr_warn(" Cannot strip M64 segment for reserved PE#%d\n",
>> phb->ioda.reserved_pe_idx);
>>@@ -294,14 +294,14 @@ static int pnv_ioda1_init_m64(struct pnv_phb *phb)
>> }
>>
>> /*
>>- * Exclude the segment used by the reserved PE, which
>>- * is expected to be 0 or last supported PE#.
>>+ * Exclude the segments for reserved and root bus PE, which
>>+ * are first or last two PEs.
>> */
>> r = &phb->hose->mem_resources[1];
>> if (phb->ioda.reserved_pe_idx == 0)
>>- r->start += phb->ioda.m64_segsize;
>>+ r->start += (2 * phb->ioda.m64_segsize);
>> else if (phb->ioda.reserved_pe_idx == (phb->ioda.total_pe_num - 1))
>>- r->end -= phb->ioda.m64_segsize;
>>+ r->end -= (2 * phb->ioda.m64_segsize);
>> else
>> pr_warn(" Cannot cut M64 segment for reserved PE#%d\n",
>> phb->ioda.reserved_pe_idx);
>>@@ -3231,7 +3231,22 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
>> phb->ioda.dma32_segmap[i] = IODA_INVALID_PE;
>> }
>> phb->ioda.pe_array = aux + pemap_off;
>>- set_bit(phb->ioda.reserved_pe_idx, phb->ioda.pe_alloc);
>>+
>>+ /*
>>+ * Choose PE number for root bus, which shouldn't have
>>+ * M64 resources consumed by its child devices. To pick
>>+ * the PE number adjacent to the reserved one if possible.
>>+ */
>>+ pnv_ioda_reserve_pe(phb, phb->ioda.reserved_pe_idx);
>>+ if (phb->ioda.reserved_pe_idx == 0) {
>>+ phb->ioda.root_pe_idx = 1;
>>+ pnv_ioda_reserve_pe(phb, phb->ioda.root_pe_idx);
>>+ } else if (phb->ioda.reserved_pe_idx == (phb->ioda.total_pe_num - 1)) {
>>+ phb->ioda.root_pe_idx = phb->ioda.reserved_pe_idx - 1;
>>+ pnv_ioda_reserve_pe(phb, phb->ioda.root_pe_idx);
>>+ } else {
>>+ phb->ioda.root_pe_idx = IODA_INVALID_PE;
>>+ }
>>
>> INIT_LIST_HEAD(&phb->ioda.pe_list);
>> mutex_init(&phb->ioda.pe_list_mutex);
>>diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
>>index e55ab0e..a8ba97f 100644
>>--- a/arch/powerpc/platforms/powernv/pci.h
>>+++ b/arch/powerpc/platforms/powernv/pci.h
>>@@ -120,6 +120,7 @@ struct pnv_phb {
>> /* Global bridge info */
>> unsigned int total_pe_num;
>> unsigned int reserved_pe_idx;
>>+ unsigned int root_pe_idx;
>>
>> /* 32-bit MMIO window */
>> unsigned int m32_size;
>>

Thanks,
Gavin