Re: [PATCH v8 09/45] powerpc/powernv: Simplify pnv_ioda_setup_pe_seg()

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Wed, Apr 13, 2016 at 04:45:39PM +1000, Alexey Kardashevskiy wrote:
>On 02/17/2016 02:43 PM, Gavin Shan wrote:
>>The original implementation of pnv_ioda_setup_pe_seg() configures
>>IO and M32 segments by separate logics, which can be merged by
>>by caching @segmap, @seg_size, @win in advance. This shouldn't
>>cause any behavioural changes.
>>
>>Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>>---
>>  arch/powerpc/platforms/powernv/pci-ioda.c | 62 ++++++++++++++-----------------
>>  1 file changed, 28 insertions(+), 34 deletions(-)
>>
>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
>>index 44cc5f3..fd7d382 100644
>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c
>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
>>@@ -2940,8 +2940,10 @@ static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
>>  	struct pnv_phb *phb = hose->private_data;
>>  	struct pci_bus_region region;
>>  	struct resource *res;
>>-	int i, index;
>>-	int rc;
>>+	unsigned int segsize;
>>+	int *segmap, index, i;
>>+	uint16_t win;
>>+	int64_t rc;
>>
>>  	/*
>>  	 * NOTE: We only care PCI bus based PE for now. For PCI
>>@@ -2958,23 +2960,9 @@ static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
>>  		if (res->flags & IORESOURCE_IO) {
>>  			region.start = res->start - phb->ioda.io_pci_base;
>>  			region.end   = res->end - phb->ioda.io_pci_base;
>>-			index = region.start / phb->ioda.io_segsize;
>>-
>>-			while (index < phb->ioda.total_pe_num &&
>>-			       region.start <= region.end) {
>>-				phb->ioda.io_segmap[index] = pe->pe_number;
>>-				rc = opal_pci_map_pe_mmio_window(phb->opal_id,
>>-					pe->pe_number, OPAL_IO_WINDOW_TYPE, 0, index);
>>-				if (rc != OPAL_SUCCESS) {
>>-					pr_err("%s: OPAL error %d when mapping IO "
>>-					       "segment #%d to PE#%d\n",
>>-					       __func__, rc, index, pe->pe_number);
>>-					break;
>>-				}
>>-
>>-				region.start += phb->ioda.io_segsize;
>>-				index++;
>>-			}
>>+			segsize      = phb->ioda.io_segsize;
>>+			segmap       = phb->ioda.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 -
>>@@ -2983,23 +2971,29 @@ static void pnv_ioda_setup_pe_seg(struct pci_controller *hose,
>>  			region.end   = res->end -
>>  				       hose->mem_offset[0] -
>>  				       phb->ioda.m32_pci_base;
>>-			index = region.start / phb->ioda.m32_segsize;
>>-
>>-			while (index < phb->ioda.total_pe_num &&
>>-			       region.start <= region.end) {
>>-				phb->ioda.m32_segmap[index] = pe->pe_number;
>>-				rc = opal_pci_map_pe_mmio_window(phb->opal_id,
>>-					pe->pe_number, OPAL_M32_WINDOW_TYPE, 0, index);
>>-				if (rc != OPAL_SUCCESS) {
>>-					pr_err("%s: OPAL error %d when mapping M32 "
>>-					       "segment#%d to PE#%d",
>>-					       __func__, rc, index, pe->pe_number);
>>-					break;
>>-				}
>>+			segsize      = phb->ioda.m32_segsize;
>>+			segmap       = phb->ioda.m32_segmap;
>>+			win          = OPAL_M32_WINDOW_TYPE;
>>+		} else {
>>+			continue;
>>+		}
>>
>>-				region.start += phb->ioda.m32_segsize;
>>-				index++;
>>+		index = region.start / segsize;
>>+		while (index < phb->ioda.total_pe_num &&
>>+		       region.start <= region.end) {
>>+			segmap[index] = pe->pe_number;
>>+			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;
>
>Please move this loop to a helper and stop caching segsize/segmap/win; this
>will make the code easier to read and the next patch will look much cleaner
>as it will not have to move this exact loop.
>

Thanks. It's good idea and I'll change the code accordingly in next revision.

>>  			}
>>+
>>+			region.start += segsize;
>>+			index++;
>>  		}
>>  	}
>>  }
>>
>
>
>-- 
>Alexey
>