riscv: dts: spacemit: enable QSPI and add SPI NOR on Milk-V Jupiter

Add the QSPI controller node for the Milk-V Jupiter board and describe
the attached SPI NOR flash (GD25Q64E).

The flash supports a frequency up to 133MHz (80 MHz for reads), and the
SoC supports a frequency up to 104 MHz. However tests have shown that
the flash is not reliably detected above 26.5 MHz, consistent with
frequency used in the vendor kernel. Therefore, use this frequency.

The m25p,fast-read properties is taken from the vendor kernel, and the
GD25Q64E datasheet confirms tha the fast read opcodes are supported.

Add a corresponding flash partition layout, matching the layout and the
names used in the vendor U-Boot.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Link: https://lore.kernel.org/r/20260326183745.1370642-5-aurelien@aurel32.net
Signed-off-by: Yixun Lan <dlan@kernel.org>

Author: aurel32

arch/riscv/boot/dts/spacemit/k1-milkv-jupiter.dts

@@ -173,7 +173,7 @@
 				regulator-always-on;
 			};
 
-			buck4 {
+			buck4_3v3: buck4 {
 				regulator-min-microvolt = <500000>;
 				regulator-max-microvolt = <3300000>;
 				regulator-ramp-delay = <5000>;
@@ -256,6 +256,47 @@
 	};
 };
 
+&qspi {
+	pinctrl-names = "default";
+	pinctrl-0 = <&qspi_cfg>;
+	status = "okay";
+
+	flash@0 {
+		compatible = "jedec,spi-nor";
+		reg = <0>;
+		spi-max-frequency = <26500000>;
+		spi-rx-bus-width = <4>;
+		spi-tx-bus-width = <4>;
+		vcc-supply = <&buck4_3v3>; /* QSPI_VCC1833 */
+		m25p,fast-read;
+
+		partitions {
+			compatible = "fixed-partitions";
+			#address-cells = <1>;
+			#size-cells = <1>;
+
+			bootinfo@0 {
+				reg = <0x0 0x10000>;
+			};
+			private@10000 {
+				reg = <0x10000 0x10000>;
+			};
+			fsbl@20000 {
+				reg = <0x20000 0x40000>;
+			};
+			env@60000 {
+				reg = <0x60000 0x10000>;
+			};
+			opensbi@70000 {
+				reg = <0x70000 0x30000>;
+			};
+			uboot@a00000 {
+				reg = <0xa0000 0x760000>;
+			};
+		};
+	};
+};
+
 &uart0 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&uart0_2_cfg>;