Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 66 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/bus/uniphier-system-bus.txt b/Documentation/devicetree/bindings/bus/uniphier-system-bus.txt
new file mode 100644
index 000000000..68ef80aff
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/uniphier-system-bus.txt
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+UniPhier System Bus
+
+The UniPhier System Bus is an external bus that connects on-board devices to
+the UniPhier SoC.  It is a simple (semi-)parallel bus with address, data, and
+some control signals.  It supports up to 8 banks (chip selects).
+
+Before any access to the bus, the bus controller must be configured; the bus
+controller registers provide the control for the translation from the offset
+within each bank to the CPU-viewed address.  The needed setup includes the base
+address, the size of each bank.  Optionally, some timing parameters can be
+optimized for faster bus access.
+
+Required properties:
+- compatible: should be "socionext,uniphier-system-bus".
+- reg: offset and length of the register set for the bus controller device.
+- #address-cells: should be 2.  The first cell is the bank number (chip select).
+  The second cell is the address offset within the bank.
+- #size-cells: should be 1.
+- ranges: should provide a proper address translation from the System Bus to
+  the parent bus.
+
+Note:
+The address region(s) that can be assigned for the System Bus is implementation
+defined.  Some SoCs can use 0x00000000-0x0fffffff and 0x40000000-0x4fffffff,
+while other SoCs can only use 0x40000000-0x4fffffff.  There might be additional
+limitations depending on SoCs and the boot mode.  The address translation is
+arbitrary as long as the banks are assigned in the supported address space with
+the required alignment and they do not overlap one another.
+For example, it is possible to map:
+  bank 0 to 0x42000000-0x43ffffff, bank 5 to 0x46000000-0x46ffffff
+It is also possible to map:
+  bank 0 to 0x48000000-0x49ffffff, bank 5 to 0x44000000-0x44ffffff
+There is no reason to stick to a particular translation mapping, but the
+"ranges" property should provide a "reasonable" default that is known to work.
+The software should initialize the bus controller according to it.
+
+Example:
+
+	system-bus {
+		compatible = "socionext,uniphier-system-bus";
+		reg = <0x58c00000 0x400>;
+		#address-cells = <2>;
+		#size-cells = <1>;
+		ranges = <1 0x00000000 0x42000000 0x02000000
+			  5 0x00000000 0x46000000 0x01000000>;
+
+		ethernet@1,01f00000 {
+			compatible = "smsc,lan9115";
+			reg = <1 0x01f00000 0x1000>;
+			interrupts = <0 48 4>
+			phy-mode = "mii";
+		};
+
+		uart@5,00200000 {
+			compatible = "ns16550a";
+			reg = <5 0x00200000 0x20>;
+			interrupts = <0 49 4>
+			clock-frequency = <12288000>;
+		};
+	};
+
+In this example,
+ - the Ethernet device is connected at the offset 0x01f00000 of CS1 and
+   mapped to 0x43f00000 of the parent bus.
+ - the UART device is connected at the offset 0x00200000 of CS5 and
+   mapped to 0x46200000 of the parent bus.