dts: wch: Enable using whole flash with CH32V208

Enables using the whole flash on CH32V208
This also involves limiting frequency of the CPU to 120Mhz
from 144Mhz to meet recommendations.

Signed-off-by: Camille BAUD <mail@massdriver.space>

Author: VynDragon

dts/riscv/wch/ch32v208/ch32v208.dtsi

@@ -37,7 +37,7 @@
 		pll: pll {
 			#clock-cells = <0>;
 			compatible = "wch,ch32v20x_30x-pll-clock";
-			mul = <18>;
+			mul = <15>;
 			status = "disabled";
 		};
 	};
@@ -54,9 +54,9 @@
 			#address-cells = <1>;
 			#size-cells = <1>;
 
-			flash0: flash@0 {
+			flash0: flash@8000000 {
 				compatible = "soc-nv-flash";
-				reg = <0 DT_SIZE_K(128)>;
+				reg = <0x08000000 DT_SIZE_K(480)>;
 			};
 		};
 
@@ -160,5 +160,5 @@
 };
 
 &cpu0 {
-	clock-frequency = <DT_FREQ_M(144)>;
+	clock-frequency = <DT_FREQ_M(120)>;
 };

soc/wch/ch32v/qingke_v4c/vector.S

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 Michael Hope
+ * Copyright (c) 2025 MASSDRIVER EI (massdriver.space)
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -18,12 +18,15 @@ GTEXT(__initialize)
 
 SECTION_FUNC(vectors, ivt)
 	.option norvc
+	/* Jump to 0x08000008, into the main flash zone where j __start is */
+	lui	x5, 0x8000
+	jr	0x8(x5)
 	j       __start
 	.rept   CONFIG_VECTOR_TABLE_SIZE
 	.word	_isr_wrapper
 	.endr
 
 SECTION_FUNC(vectors, __start)
-	li 	a0, 3
+	li 	a0, 0xf
 	csrw	mtvec, a0
 	j	__initialize