powerpc/powernv/ioda1: Introduce PNV_IODA1_DMA32_SEGSIZE

Currently, there is one macro (TCE32_TABLE_SIZE) representing the
TCE table size for one DMA32 segment. The constant representing
the DMA32 segment size (1 << 28) is still used in the code.

This defines PNV_IODA1_DMA32_SEGSIZE representing one DMA32
segment size. the TCE table size can be calcualted when the page
has fixed 4KB size. So all the related calculation depends on one
macro (PNV_IODA1_DMA32_SEGSIZE). No logical changes introduced.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-By: Alistair Popple <alistair@popple.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -50,9 +50,7 @@
 
 #define PNV_IODA1_M64_NUM	16	/* Number of M64 BARs	*/
 #define PNV_IODA1_M64_SEGS	8	/* Segments per M64 BAR	*/
-
-/* 256M DMA window, 4K TCE pages, 8 bytes TCE */
-#define TCE32_TABLE_SIZE	((0x10000000 / 0x1000) * 8)
+#define PNV_IODA1_DMA32_SEGSIZE	0x10000000
 
 #define POWERNV_IOMMU_DEFAULT_LEVELS	1
 #define POWERNV_IOMMU_MAX_LEVELS	5
@@ -2037,7 +2035,7 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
 
 	struct page *tce_mem = NULL;
 	struct iommu_table *tbl;
-	unsigned int i;
+	unsigned int tce32_segsz, i;
 	int64_t rc;
 	void *addr;
 
@@ -2057,29 +2055,34 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
 	/* Grab a 32-bit TCE table */
 	pe->tce32_seg = base;
 	pe_info(pe, " Setting up 32-bit TCE table at %08x..%08x\n",
-		(base << 28), ((base + segs) << 28) - 1);
+		base * PNV_IODA1_DMA32_SEGSIZE,
+		(base + segs) * PNV_IODA1_DMA32_SEGSIZE - 1);
 
 	/* XXX Currently, we allocate one big contiguous table for the
 	 * TCEs. We only really need one chunk per 256M of TCE space
 	 * (ie per segment) but that's an optimization for later, it
 	 * requires some added smarts with our get/put_tce implementation
+	 *
+	 * Each TCE page is 4KB in size and each TCE entry occupies 8
+	 * bytes
 	 */
+	tce32_segsz = PNV_IODA1_DMA32_SEGSIZE >> (IOMMU_PAGE_SHIFT_4K - 3);
 	tce_mem = alloc_pages_node(phb->hose->node, GFP_KERNEL,
-				   get_order(TCE32_TABLE_SIZE * segs));
+				   get_order(tce32_segsz * segs));
 	if (!tce_mem) {
 		pe_err(pe, " Failed to allocate a 32-bit TCE memory\n");
 		goto fail;
 	}
 	addr = page_address(tce_mem);
-	memset(addr, 0, TCE32_TABLE_SIZE * segs);
+	memset(addr, 0, tce32_segsz * segs);
 
 	/* Configure HW */
 	for (i = 0; i < segs; i++) {
 		rc = opal_pci_map_pe_dma_window(phb->opal_id,
 					      pe->pe_number,
 					      base + i, 1,
-					      __pa(addr) + TCE32_TABLE_SIZE * i,
-					      TCE32_TABLE_SIZE, 0x1000);
+					      __pa(addr) + tce32_segsz * i,
+					      tce32_segsz, IOMMU_PAGE_SIZE_4K);
 		if (rc) {
 			pe_err(pe, " Failed to configure 32-bit TCE table,"
 			       " err %ld\n", rc);
@@ -2088,8 +2091,9 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
 	}
 
 	/* Setup linux iommu table */
-	pnv_pci_setup_iommu_table(tbl, addr, TCE32_TABLE_SIZE * segs,
-				  base << 28, IOMMU_PAGE_SHIFT_4K);
+	pnv_pci_setup_iommu_table(tbl, addr, tce32_segsz * segs,
+				  base * PNV_IODA1_DMA32_SEGSIZE,
+				  IOMMU_PAGE_SHIFT_4K);
 
 	/* OPAL variant of P7IOC SW invalidated TCEs */
 	if (phb->ioda.tce_inval_reg)
@@ -2119,7 +2123,7 @@ static void pnv_pci_ioda1_setup_dma_pe(struct pnv_phb *phb,
 	if (pe->tce32_seg >= 0)
 		pe->tce32_seg = -1;
 	if (tce_mem)
-		__free_pages(tce_mem, get_order(TCE32_TABLE_SIZE * segs));
+		__free_pages(tce_mem, get_order(tce32_segsz * segs));
 	if (tbl) {
 		pnv_pci_unlink_table_and_group(tbl, &pe->table_group);
 		iommu_free_table(tbl, "pnv");
@@ -3456,7 +3460,8 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
 	mutex_init(&phb->ioda.pe_list_mutex);
 
 	/* Calculate how many 32-bit TCE segments we have */
-	phb->ioda.tce32_count = phb->ioda.m32_pci_base >> 28;
+	phb->ioda.tce32_count = phb->ioda.m32_pci_base /
+				PNV_IODA1_DMA32_SEGSIZE;
 
 #if 0 /* We should really do that ... */
 	rc = opal_pci_set_phb_mem_window(opal->phb_id,