chore: cc

include/rom.h

@@ -5,7 +5,6 @@
 
 extern uint32_t DiagPrintf(const char *fmt, ...)
     __attribute__((format(printf, 1, 2)));
-extern void DelayMs(uint32_t ms);
 
 #define printf DiagPrintf
 

include/rtl8710bx.h

@@ -1217,12 +1217,13 @@ typedef struct {
                      (((uint32_t)(val) << 8) & BKUP_RTC_BACKUP_MASK))
 
 /* rtl8710b_clk.h */
-#define CLK_TABLE_ROM 0x00046E68
-#define XTAL_TABLE_ROM 0x00046E10
-
 /* Clock source position and mask */
 #define CPU_CLK_POS 4
 
+/* Clock freq set macro */
+#define SET_CPU_CLOCK(source) \
+  (SYSTEM_CTRL->CLK_CTRL1 = (SYSTEM_CTRL->CLK_CTRL1 & ~SYS_CLK_CPU_CLK_SEL) | (source))
+
 /* Clock sources - values pre-shifted to position */
 #define CPU_CLK_125M (0 << CPU_CLK_POS)
 #define CPU_CLK_62_5M (1 << CPU_CLK_POS)
@@ -1231,10 +1232,6 @@ typedef struct {
 #define CPU_CLK_XTAL (4 << CPU_CLK_POS)
 #define CPU_CLK_ANA_4M (5 << CPU_CLK_POS)
 
-/* Clock control macro */
-#define SET_CPU_CLOCK(source) \
-  (SYSTEM_CTRL->CLK_CTRL1 = (SYSTEM_CTRL->CLK_CTRL1 & ~CPU_CLK_MASK) | (source))
-
 /* NCO32k (NCO1) CLK_INFO Register Bits */
 #define NCO1_CLK_INFO_FREQ_MASK 0x00FFFFFF /* Unregulated clock freq */
 #define NCO1_CLK_INFO_32K_RDY (1 << 24)    /* 32K clock output rdy */

include/startup.h

@@ -1,9 +0,0 @@
-#ifndef STARTUP_H
-#define STARTUP_H
-
-#include <stdint.h>
-
-// from bootloader
-extern uint32_t SystemCoreClock;
-
-#endif // STARTUP_H

include/system_rtl8710bx.h

@@ -0,0 +1,43 @@
+#ifndef SYSTEM_RTL8710BX
+#define SYSTEM_RTL8710BX
+
+#include <stdint.h>
+
+#ifdef USE_ROM_TABLES
+#define CPU_CLK_TABLE 0x00046E68
+#define XTAL_TABLE_ROM 0x00046E10
+#else
+
+/* CPU clock frequency table (Hz) */
+static const uint32_t CPU_CLK_TABLE[] = {
+    125000000, /* 125 MHz */
+    62500000,  /* 62.5 MHz */
+    31250000,  /* 31.25 MHz */
+    15625000,  /* 15.625 MHz */
+    7812500,   /* 7.8125 MHz */
+    4000000    /* 4 MHz */
+};
+
+/* Crystal oscillator frequency table (Hz) */
+static const uint32_t XTAL_TABLE[] = {
+    40000000, /* 40 MHz */
+    25000000, /* 25 MHz */
+    13000000, /* 13 MHz */
+    19200000, /* 19.2 MHz */
+    20000000, /* 20 MHz */
+    26000000, /* 26 MHz */
+    38400000, /* 38.4 MHz */
+    17664000, /* 17.664 MHz */
+    16000000, /* 16 MHz */
+    14318000, /* 14.318 MHz */
+    12000000, /* 12 MHz */
+};
+#endif
+
+/* System Clock Frequency (Core Clock)*/
+extern uint32_t SystemCoreClock;
+
+void SystemCoreClockUpdate(void);
+void SystemInit(void);
+
+#endif  // SYSTEM_RTL8710BX

src/boot.s

@@ -1,40 +1,6 @@
 .syntax unified
 .cpu cortex-m4
 
-.section .data
-.global SystemCoreClock
-SystemCoreClock: .word 0
-
-/* these match defines in rtl8710bx.h */
-.equ SYSON_CLK_CTRL1, 0x40000014
-.equ CLK_TABLE_ROM,   0x46E68
-.equ CPU_CLK_POS,     4
-
-.section .text
-.thumb_func
-_startup:
-    /* zero .bss section */
-    ldr r0, =_bss_start
-    ldr r1, =_bss_end
-    movs r2, #0
-1:  cmp r0, r1
-    itt lt
-    strlt r2, [r0], #4
-    blt 1b
-
-    /* set up SystemCoreClock */
-    ldr r0, =SYSON_CLK_CTRL1
-    ldr r2, =CLK_TABLE_ROM
-    ldr r1, [r0]
-    ldr r0, =SystemCoreClock
-    lsrs r1, r1, #CPU_CLK_POS
-    ldr r2, [r2, r1, lsl #2]
-    str r2, [r0]
-
-    cpsie i
-    bl main
-1:  b 1b
-
 .global _init
 /* cold boot from ROM */
 _init:
@@ -44,7 +10,7 @@ _init:
     ldr r1, =0xE000ED08
     str r0, [r1]
 
-    b _startup
+    b SystemInit
 
 .section .vectors
 .global _vector_table
@@ -274,6 +240,6 @@ Default_Handler:
 .global Reset_Handler
 .thumb_func
 Reset_Handler:
-    b _startup
+    b SystemInit
 
 .end

src/main.c

@@ -3,7 +3,7 @@
 
 #include "rom.h"
 #include "rtl8710bx.h"
-#include "startup.h"
+#include "system_rtl8710bx.h"
 
 __attribute__((interrupt)) void SysTick_Handler(void) {
   GPIOA->DR ^= (1 << 23);
@@ -13,15 +13,17 @@ int main(void) {
   printf("[main]\n");
   printf("VTOR: 0x%08x\n", SCB->VTOR);
   printf("SystemCoreClock: %d Hz\n", SystemCoreClock);
+  SET_CPU_CLOCK(CPU_CLK_62_5M);
+  SystemCoreClockUpdate();
+  printf("SystemCoreClock afer update: %d Hz\n", SystemCoreClock);
 
-  SysTick_Config(100);  // tick every 100 cycles
+  SysTick_Config(100);  // tick / 100 cycles
 
   PERI_ON->SOC_PERI_FUNC1_EN |= BIT_PERI_GPIO_EN;
   PERI_ON->PESOC_CLK_CTRL |= APBPeriph_GPIO_CLOCK;
   PINMUX_Config(_PA_0, PINMUX_FN_GPIO, GPIO_PuPd_DOWN);
   PINMUX_Config(_PA_23, PINMUX_FN_GPIO, GPIO_PuPd_NOPULL);
   GPIOA->DDR |= (1 << 0) | (1 << 23);
-  // GPIOA->DDR |= (1 << 23);
 
   while (1) {
   }

src/system_rtl8710bx.c

@@ -0,0 +1,43 @@
+#include "system_rtl8710bx.h"
+
+#include <stdint.h>
+
+#include "rtl8710bx.h"
+
+uint32_t SystemCoreClock;
+
+void SystemCoreClockUpdate(void) {
+  uint32_t current_clk_idx =
+      (SYSTEM_CTRL->CLK_CTRL1 & SYS_CLK_CPU_CLK_SEL) >> CPU_CLK_POS;
+  SystemCoreClock = CPU_CLK_TABLE[current_clk_idx];
+}
+
+__attribute__((naked)) void SystemInit(void) {
+  asm volatile(
+      /* zero .bss section */
+      "ldr r0, =_bss_start\n"
+      "ldr r1, =_bss_end\n"
+      "movs r2, #0\n"
+      "1:\n"
+      "cmp r0, r1\n"
+      "itt lt\n"
+      "strlt r2, [r0], #4\n"
+      "blt 1b\n"
+      "\n"
+      /* set up SystemCoreClock */
+      "ldr r0, =%0\n"
+      "ldr r2, =%1\n"
+      "ldr r1, [r0]\n"
+      "ldr r0, =%2\n"
+      "lsrs r1, r1, %3\n"
+      "ldr r2, [r2, r1, lsl #2]\n"
+      "str r2, [r0]\n"
+      "\n"
+      "cpsie i\n"
+      "bl main\n"
+      "b 1b\n" /* if main ever returns */
+      :
+      : "i"(&SYSTEM_CTRL->CLK_CTRL1), "i"(&CPU_CLK_TABLE),
+        "i"(&SystemCoreClock), "i"(CPU_CLK_POS)
+      : "r0", "r1", "r2", "r3", "memory");
+}