add boilerplate stm32h5 entrypoint

src/stm32/stm32h5.c

@@ -3,3 +3,97 @@
 // Copyright (C) 2024 Philipp Molitor <phil.x64 at gmail.com>
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "autoconf.h" // CONFIG_CLOCK_REF_FREQ
+#include "board/armcm_boot.h" // VectorTable
+#include "board/armcm_reset.h" // try_request_canboot
+#include "board/irq.h" // irq_disable
+#include "board/misc.h" // bootloader_request
+#include "command.h" // DECL_CONSTANT_STR
+#include "internal.h" // get_pclock_frequency
+#include "sched.h" // sched_main
+
+
+/****************************************************************
+ * Clock setup
+ ****************************************************************/
+
+#define FREQ_PERIPH (CONFIG_CLOCK_FREQ / 4)
+
+// Map a peripheral address to its enable bits
+struct cline
+lookup_clock_line(uint32_t periph_base)
+{
+#error "TODO"
+}
+
+// Return the frequency of the given peripheral clock
+uint32_t
+get_pclock_frequency(uint32_t periph_base)
+{
+    return FREQ_PERIPH;
+}
+
+// Enable a GPIO peripheral clock
+void
+gpio_clock_enable(GPIO_TypeDef *regs)
+{
+#error "TODO"
+}
+
+// TODO: check what pins apply to stm32h5
+/*
+#if !CONFIG_STM32_CLOCK_REF_INTERNAL
+DECL_CONSTANT_STR("RESERVE_PINS_crystal", "PH0,PH1");
+#endif
+*/
+
+// Main clock and power setup called at chip startup
+static void
+clock_setup(void)
+{
+#error "TODO"
+}
+
+
+/****************************************************************
+ * Bootloader
+ ****************************************************************/
+
+// Handle reboot requests
+void
+bootloader_request(void)
+{
+    try_request_canboot();
+    dfu_reboot();
+}
+
+
+/****************************************************************
+ * Startup
+ ****************************************************************/
+
+// Main entry point - called from armcm_boot.c:ResetHandler()
+void
+armcm_main(void)
+{
+    // TODO: stm32g0 (which seems to be closely related) has a different
+    //       routine for this. Check if it applies to stm32h5 as well.
+
+    // Run SystemInit() and then restore VTOR
+    SystemInit();
+
+    // TODO: more registers to reset?
+    RCC->APB1LENR = 0x00000000;
+    RCC->APB1HENR = 0x00000000;
+    RCC->APB2ENR = 0x00000000;
+    RCC->APB3ENR = 0x00000000;
+
+    SCB->VTOR = (uint32_t)VectorTable;
+
+    dfu_reboot_check();
+
+    clock_setup();
+
+    sched_main();
+}