Subject: Re: [PATCH v6 07/42] powerpc/powernv: Improve IO and M32 mapping

From: Gavin Shan <[email-masked]>
Date: Tue, 11 Aug 2015 10:12:59 +1000

On Mon, Aug 10, 2015 at 05:40:08PM +1000, Alexey Kardashevskiy wrote:
>On 08/06/2015 02:11 PM, Gavin Shan wrote:
>>There're 3 windows (IO, M32 and M64) for PHB, root port and upstream
>
>These are actually IO, non-prefetchable and prefetchable windows which happen
>to be IO, 32bit and 64bit windows but this has nothing to do with the M32/M64
>BAR registers in P7IOC/PHB3, do I understand this correctly?
>

In pci-ioda.c, we have below definiations that are defined when
developing the code, not from any specification:

IO  - resources with IO property
M32 - 32-bits or non-prefetchable resources
M64 - 64-bits and prefetchable resources

>>port of the PCIE switch behind root port. In order to support PCI
>>hotplug, we extend the start/end address of those 3 windows of root
>>port or upstream port to the start/end address of the 3 PHB's windows.
>>The current implementation, assigning IO or M32 segment based on the
>>bridge's windows, isn't reliable.
>>
>>The patch fixes above issue by calculating PE's consumed IO or M32
>>segments from its contained devices, no PCI bridge windows involved
>>if the PE doesn't contain all the subordinate PCI buses.
>
>Please, rephrase it. How can PCI bridges be involved in PE consumption?
>

Ok. Will add something like below:

if the PE, corresponding to the PCI bus, doesn't contain all the subordinate
PCI buses.

>
>>Otherwise,
>>the PCI bridge windows still contribute to PE's consumed IO or M32
>>segments.
>
>PCI bridge windows themselves consume PEs? Is that correct?
>

PCI bridge windows consume IO, M32, M64 segments, not PEs.

>>
>>Signed-off-by: Gavin Shan <[email-masked]>
>>---
>>  arch/powerpc/platforms/powernv/pci-ioda.c | 136 +++++++++++++++++-------------
>>  1 file changed, 79 insertions(+), 57 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index 488a53e..713f4b4 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -2844,75 +2844,97 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
>>  }
>>  #endif /* CONFIG_PCI_IOV */
>>
>>-/*
>>- * This function is supposed to be called on basis of PE from top
>>- * to bottom style. So the the I/O or MMIO segment assigned to
>>- * parent PE could be overrided by its child PEs if necessary.
>>- */
>>-static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
>>-				  struct pnv_ioda_pe *pe)
>>+static int pnv_ioda_setup_one_res(struct pci_controller *hose,
>>+				  struct pnv_ioda_pe *pe,
>>+				  struct resource *res)
>>  {
>>  	struct pnv_phb *phb = hose->private_data;
>>  	struct pci_bus_region region;
>>-	struct resource *res;
>>-	int i, index;
>>-	unsigned int segsize;
>>+	unsigned int index, segsize;
>>  	unsigned long *segmap, *pe_segmap;
>>  	uint16_t win;
>>  	int64_t rc;
>>
>>-	/*
>>-	 * NOTE: We only care PCI bus based PE for now. For PCI
>>-	 * device based PE, for example SRIOV sensitive VF should
>>-	 * be figured out later.
>>-	 */
>>-	BUG_ON(!(pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL)));
>>+	/* Check if we need map the resource */
>>+	if (!res->parent || !res->flags || res->start > res->end)
>
>res->start >= res->end ?
>

No, res->start == res->end is valid.

>
>>+		return 0;
>>
>>-	pci_bus_for_each_resource(pe->pbus, res, i) {
>>-		if (!res || !res->flags ||
>>-		    res->start > res->end)
>>-			continue;
>>+	if (res->flags & IORESOURCE_IO) {
>>+		region.start = res->start - phb->ioda.io_pci_base;
>>+		region.end   = res->end - phb->ioda.io_pci_base;
>>+		segsize      = phb->ioda.io_segsize;
>>+		segmap       = phb->ioda.io_segmap;
>>+		pe_segmap    = pe->io_segmap;
>>+		win          = OPAL_IO_WINDOW_TYPE;
>>+	} else if ((res->flags & IORESOURCE_MEM) &&
>>+		   !pnv_pci_is_mem_pref_64(res->flags)) {
>>+		region.start = res->start -
>>+			       hose->mem_offset[0] -
>>+			       phb->ioda.m32_pci_base;
>>+		region.end   = res->end -
>>+			       hose->mem_offset[0] -
>>+			       phb->ioda.m32_pci_base;
>>+		segsize      = phb->ioda.m32_segsize;
>>+		segmap       = phb->ioda.m32_segmap;
>>+		pe_segmap    = pe->m32_segmap;
>>+		win          = OPAL_M32_WINDOW_TYPE;
>>+	} else {
>>+		return 0;
>>+	}
>>
>>-		if (res->flags & IORESOURCE_IO) {
>>-			region.start = res->start - phb->ioda.io_pci_base;
>>-			region.end   = res->end - phb->ioda.io_pci_base;
>>-			segsize      = phb->ioda.io_segsize;
>>-			segmap       = phb->ioda.io_segmap;
>>-			pe_segmap    = pe->io_segmap;
>>-			win          = OPAL_IO_WINDOW_TYPE;
>>-		} else if ((res->flags & IORESOURCE_MEM) &&
>>-			   !pnv_pci_is_mem_pref_64(res->flags)) {
>>-			region.start = res->start -
>>-				       hose->mem_offset[0] -
>>-				       phb->ioda.m32_pci_base;
>>-			region.end   = res->end -
>>-				       hose->mem_offset[0] -
>>-				       phb->ioda.m32_pci_base;
>>-			segsize      = phb->ioda.m32_segsize;
>>-			segmap       = phb->ioda.m32_segmap;
>>-			pe_segmap    = pe->m32_segmap;
>>-			win          = OPAL_M32_WINDOW_TYPE;
>>-		} else {
>>-			continue;
>>+	region.start = _ALIGN_DOWN(region.start, segsize);
>>+	region.end   = _ALIGN_UP(region.end, segsize);
>>+	index = region.start / segsize;
>>+	while (index < phb->ioda.total_pe &&
>>+	       region.start < region.end) {
>>+		rc = opal_pci_map_pe_mmio_window(phb->opal_id,
>>+				pe->pe_number, win, 0, index);
>>+		if (rc != OPAL_SUCCESS) {
>>+			pr_warn("%s: Error %lld mapping (%d) seg#%d to PHB#%d-PE#%d\n",
>>+				__func__, rc, win, index,
>>+				pe->phb->hose->global_number,
>>+				pe->pe_number);
>>+			return -EIO;
>>  		}
>>
>>-		index = region.start / phb->ioda.io_segsize;
>>-		while (index < phb->ioda.total_pe &&
>>-		       region.start <= region.end) {
>>-			set_bit(index, segmap);
>>-			set_bit(index, pe_segmap);
>>-			rc = opal_pci_map_pe_mmio_window(phb->opal_id,
>>-					pe->pe_number, win, 0, index);
>>-			if (rc != OPAL_SUCCESS) {
>>-				pr_warn("%s: Error %lld mapping (%d) seg#%d to PHB#%d-PE#%d\n",
>>-					__func__, rc, win, index,
>>-					pe->phb->hose->global_number,
>>-					pe->pe_number);
>>-				break;
>>-			}
>>+		set_bit(index, segmap);
>>+		set_bit(index, pe_segmap);
>>+		region.start += segsize;
>>+		index++;
>>+	}
>>+
>>+	return 0;
>>+}
>>+
>>+static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
>>+				  struct pnv_ioda_pe *pe)
>>+{
>>+	struct pci_dev *pdev;
>>+	struct resource *res;
>>+	int i;
>>+
>>+	/* This function only works for bus dependent PE */
>>+	BUG_ON(!(pe->flags & (PNV_IODA_PE_BUS | PNV_IODA_PE_BUS_ALL)));
>>+
>>+	list_for_each_entry(pdev, &pe->pbus->devices, bus_list) {
>>+		for (i = 0; i <= PCI_ROM_RESOURCE; i++) {
>>+			res = &pdev->resource[i];
>>+			if (pnv_ioda_setup_one_res(hose, pe, res))
>>+				return;
>>+		}
>>+
>>+		/* If the PE contains all subordinate PCI buses, the
>>+		 * resources of the child bridges should be mapped
>>+		 * to the PE as well.
>>+		 */
>>+		if (!(pe->flags & PNV_IODA_PE_BUS_ALL) ||
>>+		    (pdev->class >> 8) != PCI_CLASS_BRIDGE_PCI)
>>+			continue;
>>
>>-			region.start += segsize;
>>-			index++;
>>+		for (i = 0; i <= PCI_BRIDGE_RESOURCE_NUM; i++) {
>>+			res = &pdev->resource[PCI_BRIDGE_RESOURCES + i];
>>+			if (pnv_ioda_setup_one_res(hose, pe, res))
>>+				return;
>>  		}
>>  	}
>>  }
>>

Thanks,
Gavin