49 lines
1.1 KiB
C
49 lines
1.1 KiB
C
#include <stdint.h>
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#define UART0_BASE 0x05000000
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#define R_WDOG_BASE 0x07020400
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#define WDOG_CTRL_KEY (0xA57 << 1)
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#define WDOG_CTRL_RESTART (1 << 0)
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#define WDOG_CFG_SYS (1 << 0)
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#define WDOG_MODE_EN (1 << 0)
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struct watchdog {
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uint32_t irq_en;
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uint32_t irq_sta;
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uint32_t res[2];
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uint32_t ctrl;
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uint32_t cfg;
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uint32_t mode;
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};
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static volatile struct watchdog *const r_wdog = (struct watchdog *) R_WDOG_BASE;
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static inline void delay(uint32_t t) {
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for (uint32_t i = 0; i < t; ++i) {
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asm volatile ("nop");
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}
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}
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static void uart_tx(uint8_t byte) {
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*((uint8_t *) UART0_BASE) = byte;
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}
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static _Noreturn void board_reset(void) {
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// NOTE: this seems to be the suggested method for
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// h6 board reset according to u-boot
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r_wdog->cfg = WDOG_CFG_SYS;
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r_wdog->mode = WDOG_MODE_EN;
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r_wdog->ctrl = WDOG_CTRL_KEY | WDOG_CTRL_RESTART;
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while (1);
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}
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_Noreturn void kernel_main(uintptr_t dt_phys_addr) {
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for (const char *p = "It's alive\r\n"; *p; ++p) {
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uart_tx(*p);
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delay(1000);
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}
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board_reset();
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}
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