dm: pci: add option to map virtual system memory base address

On MIPS the DRAM start address respectively CONFIG_SYS_SDRAM_BASE
is still used as a virtual, CPU-mapped address instead of being used
as physical address. Converting all MIPS boards and generic MIPS code
to fix that is not trivial. Due to the approaching deadline for
PCI DM conversion, this workaround is required for MIPS boards with
PCI support until the CONFIG_SYS_SDRAM_BASE issue could be solved.

Add a compile-time option to let the PCI uclass core optionally map
the DRAM address to a physical address when adding the PCI region
of type PCI_REGION_SYS_MEMORY.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

Reviewed-by: Stefan Roese <sr@denx.de>

drivers/pci/Kconfig

@@ -54,6 +54,19 @@ config PCI_REGION_MULTI_ENTRY
 	  region type. This helps to add support for SoC's like OcteonTX/TX2
 	  where every peripheral is on the PCI bus.
 
+config PCI_MAP_SYSTEM_MEMORY
+	bool "Map local system memory from a virtual base address"
+	depends on PCI || DM_PCI
+	depends on MIPS
+	default n
+	help
+	  Say Y if base address of system memory is being used as a virtual address
+	  instead of a physical address (e.g. on MIPS). The PCI core will then remap
+	  the virtual memory base address to a physical address when adding the PCI
+	  region of type PCI_REGION_SYS_MEMORY.
+	  This should only be required on MIPS where CONFIG_SYS_SDRAM_BASE is still
+	  being used as virtual address.
+
 config PCI_SRIOV
 	bool "Enable Single Root I/O Virtualization support for PCI"
 	depends on PCI || DM_PCI

drivers/pci/pci-uclass.c

@@ -1034,10 +1034,13 @@ static void decode_regions(struct pci_controller *hose, ofnode parent_node,
 
 	for (i = 0; i < CONFIG_NR_DRAM_BANKS; ++i) {
 		if (bd->bi_dram[i].size) {
+			phys_addr_t start = bd->bi_dram[i].start;
+
+			if (IS_ENABLED(CONFIG_PCI_MAP_SYSTEM_MEMORY))
+				start = virt_to_phys((void *)(uintptr_t)bd->bi_dram[i].start);
+
 			pci_set_region(hose->regions + hose->region_count++,
-				       bd->bi_dram[i].start,
-				       bd->bi_dram[i].start,
-				       bd->bi_dram[i].size,
+				       start, start, bd->bi_dram[i].size,
 				       PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
 		}
 	}