Add littlefs_shim.c

include/littlefs_shim.h

@@ -0,0 +1,31 @@
+#ifndef ROCKETLIB_LITTLEFS_SHIM_H
+#define ROCKETLIB_LITTLEFS_SHIM_H
+
+#include "lfs.h"
+#include "stm32h7xx_hal_sd.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// External SD handle used by the shim
+extern SD_HandleTypeDef *lfsshim_hsd;
+
+extern uint32_t lfsshim_first_block_offset;
+
+// LittleFS-compatible SD card interface functions
+int lfsshim_read(const struct lfs_config *c, lfs_block_t block, lfs_off_t off, void *buffer,
+				 lfs_size_t size);
+
+int lfsshim_write(const struct lfs_config *c, lfs_block_t block, lfs_off_t off, const void *buffer,
+				  lfs_size_t size);
+
+int lfsshim_erase(const struct lfs_config *c, lfs_block_t block);
+
+int lfsshim_sync(const struct lfs_config *c);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // ROCKETLIB_LITTLEFS_SHIM_H

stm32h7/littlefs_shim.c

@@ -0,0 +1,71 @@
+#include "stm32h7xx_hal.h"
+#include "lfs.h"
+#include "common.h"
+
+SD_HandleTypeDef* lfsshim_hsd;
+uint32_t lfsshim_first_block_offset = 0;
+
+uint32_t SD_RW_TIMEOUT_MS = 50U;
+
+int lfsshim_read(const struct lfs_config *c, lfs_block_t block, lfs_off_t off, void *buffer,
+			lfs_size_t size) {
+	uint32_t timeout_ms = SD_RW_TIMEOUT_MS;
+	uint32_t block_addr = block + lfsshim_first_block_offset;
+	//uint32_t num_blocks = (size + c->block_size - 1) / c->block_size;
+	uint32_t num_blocks = size / c->block_size;
+	w_assert((size % c->block_size) == 0);
+	w_assert(off == 0);
+	HAL_StatusTypeDef hal =
+		HAL_SD_ReadBlocks(lfsshim_hsd, (uint8_t *)buffer, block_addr, num_blocks, timeout_ms);
+	if (hal != HAL_OK) {
+		return -1; // LFS_ERR_IO
+	}
+
+	// Wait for card to be ready (polling)
+	uint32_t start = HAL_GetTick();
+	while (HAL_SD_GetCardState(lfsshim_hsd) != HAL_SD_CARD_TRANSFER) {
+		if ((HAL_GetTick() - start) > timeout_ms) {
+			return -1; // timeout -> LFS_ERR_IO
+		}
+	}
+
+	return 0; // success
+}
+
+int lfsshim_write(const struct lfs_config *c, lfs_block_t block, lfs_off_t off, const void *buffer,
+			 lfs_size_t size) {
+	uint32_t timeout_ms = SD_RW_TIMEOUT_MS;
+	uint32_t block_addr = block + lfsshim_first_block_offset;
+	//uint32_t num_blocks = (size + c->block_size - 1) / c->block_size;
+	uint32_t num_blocks = 1;
+	if(size != 512){
+		for(;;){}
+	}
+	if(off != 0){
+		for(;;){}
+	}
+
+	HAL_StatusTypeDef hal =
+		HAL_SD_WriteBlocks(lfsshim_hsd, (uint8_t *)buffer, block_addr, num_blocks, timeout_ms);
+	if (hal != HAL_OK) {
+		return -1; // LFS_ERR_IO
+	}
+
+	// Wait for card to be ready (polling)
+	uint32_t start = HAL_GetTick();
+	while (HAL_SD_GetCardState(lfsshim_hsd) != HAL_SD_CARD_TRANSFER) {
+		if ((HAL_GetTick() - start) > timeout_ms) {
+			return -1; // timeout -> LFS_ERR_IO
+		}
+	}
+
+	return 0; // success
+}
+
+int lfsshim_erase(const struct lfs_config *c, lfs_block_t block) {
+	return 0; // SD does not require explicit erase
+}
+
+int lfsshim_sync(const struct lfs_config *c) {
+	return 0;
+}