add support for a small filesystem on the watch

watch-library/hardware/watch/watch_storage.c

@@ -0,0 +1,94 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include "watch_storage.h"
+
+#define RWWEE_ADDR_START NVMCTRL_RWW_EEPROM_ADDR
+#define RWWEE_ADDR_END (NVMCTRL_RWW_EEPROM_ADDR + NVMCTRL_PAGE_SIZE * NVMCTRL_RWWEE_PAGES)
+#define NVM_MEMORY ((volatile uint16_t *)FLASH_ADDR)
+
+static bool _is_valid_address(uint32_t addr, uint32_t size) {
+    if ((addr < NVMCTRL_RWW_EEPROM_ADDR) || (addr > (NVMCTRL_RWW_EEPROM_ADDR + NVMCTRL_PAGE_SIZE * NVMCTRL_RWWEE_PAGES))) {
+        return false;
+    }
+    if ((addr + size > (NVMCTRL_RWW_EEPROM_ADDR + NVMCTRL_PAGE_SIZE * NVMCTRL_RWWEE_PAGES))) {
+        return false;
+    }
+
+    return true;
+}
+
+bool watch_storage_read(uint32_t row, uint32_t offset, uint8_t *buffer, uint32_t size) {
+    uint32_t address = RWWEE_ADDR_START + row * NVMCTRL_ROW_SIZE + offset;
+    if (!_is_valid_address(address, size)) return false;
+
+    uint32_t nvm_address = address / 2;
+    uint32_t i;
+    uint16_t data;
+
+    watch_storage_sync();
+
+    if (address % 2) {
+        data      = NVM_MEMORY[nvm_address++];
+        buffer[0] = data >> 8;
+        i         = 1;
+    } else {
+        i = 0;
+    }
+
+    while (i < size) {
+        data = NVM_MEMORY[nvm_address++];
+        buffer[i] = (data & 0xFF);
+        if (i < (size - 1)) {
+            buffer[i + 1] = (data >> 8);
+        }
+        i += 2;
+    }
+    return true;
+}
+
+bool watch_storage_write(uint32_t row, uint32_t offset, const uint8_t *buffer, uint32_t size) {
+    uint32_t address = RWWEE_ADDR_START + row * NVMCTRL_ROW_SIZE + offset;
+    if (!_is_valid_address(address, size)) return false;
+
+    watch_storage_sync();
+
+	uint32_t nvm_address = address / 2;
+	uint16_t i, data;
+
+	hri_nvmctrl_write_CTRLA_reg(NVMCTRL, NVMCTRL_CTRLA_CMD_PBC | NVMCTRL_CTRLA_CMDEX_KEY);
+    watch_storage_sync();
+
+	for (i = 0; i < size; i += 2) {
+		data = buffer[i];
+		if (i < NVMCTRL_PAGE_SIZE - 1) {
+			data |= (buffer[i + 1] << 8);
+		}
+		NVM_MEMORY[nvm_address++] = data;
+	}
+	hri_nvmctrl_write_ADDR_reg(NVMCTRL, address / 2);
+	hri_nvmctrl_write_CTRLA_reg(NVMCTRL, NVMCTRL_CTRLA_CMD_RWWEEWP | NVMCTRL_CTRLA_CMDEX_KEY);
+
+    return true;
+}
+
+bool watch_storage_erase(uint32_t row) {
+    uint32_t address = RWWEE_ADDR_START + row * NVMCTRL_ROW_SIZE;
+    if (!_is_valid_address(address, NVMCTRL_ROW_SIZE)) return false;
+
+    watch_storage_sync();
+    hri_nvmctrl_write_ADDR_reg(NVMCTRL, address / 2);
+    hri_nvmctrl_write_CTRLA_reg(NVMCTRL, NVMCTRL_CTRLA_CMD_RWWEEER | NVMCTRL_CTRLA_CMDEX_KEY);
+
+    return true;
+}
+
+bool watch_storage_sync(void) {
+    while (!hri_nvmctrl_get_interrupt_READY_bit(NVMCTRL)) {
+        // wait for flash to become ready
+    }
+
+    hri_nvmctrl_clear_STATUS_reg(NVMCTRL, NVMCTRL_STATUS_MASK);
+
+    return true;
+}