[PATCH v2 1/3] of: address: Add cpu_untranslate_addr to struct of_pci_range

[Frank Li <Frank.Li@xxxxxxx>]

Introduce field 'cpu_untranslate_addr' in of_pci_range to retrieve
untranslated CPU address information. This is required for hardware like
i.MX8QXP to configure the PCIe controller ATU and eliminate the need for
workaround address fixups in drivers. Currently, many drivers use
hardcoded CPU addresses for fixups, but this information is already
described in the Device Tree. With correct hardware descriptions, such
fixups can be removed.

            ┌─────────┐                    ┌────────────┐
 ┌─────┐    │         │ IA: 0x8ff0_0000    │            │
 │ CPU ├───►│ BUS     ├─────────────────┐  │ PCI        │
 └─────┘    │         │ IA: 0x8ff8_0000 │  │            │
  CPU Addr  │ Fabric  ├─────────────┐   │  │ Controller │
0x7000_0000 │         │             │   │  │            │
            │         │             │   │  │            │   PCI Addr
            │         │             │   └──► CfgSpace  ─┼────────────►
            │         ├─────────┐   │      │            │    0
            │         │         │   │      │            │
            └─────────┘         │   └──────► IOSpace   ─┼────────────►
                                │          │            │    0
                                │          │            │
                                └──────────► MemSpace  ─┼────────────►
                        IA: 0x8000_0000    │            │  0x8000_0000
                                           └────────────┘

bus@5f000000 {
        compatible = "simple-bus";
        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0x5f000000 0x0 0x5f000000 0x21000000>,
                 <0x80000000 0x0 0x70000000 0x10000000>;

        pcieb: pcie@5f010000 {
                compatible = "fsl,imx8q-pcie";
                reg = <0x5f010000 0x10000>, <0x8ff00000 0x80000>;
                reg-names = "dbi", "config";
                #address-cells = <3>;
                #size-cells = <2>;
                device_type = "pci";
                bus-range = <0x00 0xff>;
                ranges = <0x81000000 0 0x00000000 0x8ff80000 0 0x00010000>,
                         <0x82000000 0 0x80000000 0x80000000 0 0x0ff00000>;
	...
	};
};

'cpu_untranslate_addr' in of_pci_range can indicate above diagram IA
address information.

Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Change from v1 to v2
- add cpu_untranslate_addr in of_pci_range, instead adding new API.
---
 drivers/of/address.c       | 2 ++
 include/linux/of_address.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/of/address.c b/drivers/of/address.c
index 286f0c161e332..f4cb82f5313cf 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -811,6 +811,8 @@ struct of_pci_range *of_pci_range_parser_one(struct of_pci_range_parser *parser,
 	else
 		range->cpu_addr = of_translate_address(parser->node,
 				parser->range + na);
+
+	range->cpu_untranslate_addr = of_read_number(parser->range + na, parser->pna);
 	range->size = of_read_number(parser->range + parser->pna + na, ns);
 
 	parser->range += np;
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 26a19daf0d092..0683ce0c07f68 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -26,6 +26,7 @@ struct of_pci_range {
 		u64 bus_addr;
 	};
 	u64 cpu_addr;
+	u64 cpu_untranslate_addr;
 	u64 size;
 	u32 flags;
 };

-- 
2.34.1