Implement storedevs, prepare to port littlefs

kernel/fs/littlefs/bd/lfs_rambd.c

@@ -0,0 +1,118 @@
+/*
+ * Block device emulated in RAM
+ *
+ * Copyright (c) 2022, The littlefs authors.
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "bd/lfs_rambd.h"
+
+int lfs_rambd_create(const struct lfs_config *cfg,
+        const struct lfs_rambd_config *bdcfg) {
+    LFS_RAMBD_TRACE("lfs_rambd_create(%p {.context=%p, "
+                ".read=%p, .prog=%p, .erase=%p, .sync=%p}, "
+                "%p {.read_size=%"PRIu32", .prog_size=%"PRIu32", "
+                ".erase_size=%"PRIu32", .erase_count=%"PRIu32", "
+                ".buffer=%p})",
+            (void*)cfg, cfg->context,
+            (void*)(uintptr_t)cfg->read, (void*)(uintptr_t)cfg->prog,
+            (void*)(uintptr_t)cfg->erase, (void*)(uintptr_t)cfg->sync,
+            (void*)bdcfg,
+            bdcfg->read_size, bdcfg->prog_size, bdcfg->erase_size,
+            bdcfg->erase_count, bdcfg->buffer);
+    lfs_rambd_t *bd = cfg->context;
+    bd->cfg = bdcfg;
+
+    // allocate buffer?
+    if (bd->cfg->buffer) {
+        bd->buffer = bd->cfg->buffer;
+    } else {
+        bd->buffer = lfs_malloc(bd->cfg->erase_size * bd->cfg->erase_count);
+        if (!bd->buffer) {
+            LFS_RAMBD_TRACE("lfs_rambd_create -> %d", LFS_ERR_NOMEM);
+            return LFS_ERR_NOMEM;
+        }
+    }
+
+    // zero for reproducibility
+    memset(bd->buffer, 0, bd->cfg->erase_size * bd->cfg->erase_count);
+
+    LFS_RAMBD_TRACE("lfs_rambd_create -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_destroy(const struct lfs_config *cfg) {
+    LFS_RAMBD_TRACE("lfs_rambd_destroy(%p)", (void*)cfg);
+    // clean up memory
+    lfs_rambd_t *bd = cfg->context;
+    if (!bd->cfg->buffer) {
+        lfs_free(bd->buffer);
+    }
+    LFS_RAMBD_TRACE("lfs_rambd_destroy -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_read(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, void *buffer, lfs_size_t size) {
+    LFS_RAMBD_TRACE("lfs_rambd_read(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if read is valid
+    LFS_ASSERT(block < bd->cfg->erase_count);
+    LFS_ASSERT(off  % bd->cfg->read_size == 0);
+    LFS_ASSERT(size % bd->cfg->read_size == 0);
+    LFS_ASSERT(off+size <= bd->cfg->erase_size);
+
+    // read data
+    memcpy(buffer, &bd->buffer[block*bd->cfg->erase_size + off], size);
+
+    LFS_RAMBD_TRACE("lfs_rambd_read -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_prog(const struct lfs_config *cfg, lfs_block_t block,
+        lfs_off_t off, const void *buffer, lfs_size_t size) {
+    LFS_RAMBD_TRACE("lfs_rambd_prog(%p, "
+                "0x%"PRIx32", %"PRIu32", %p, %"PRIu32")",
+            (void*)cfg, block, off, buffer, size);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if write is valid
+    LFS_ASSERT(block < bd->cfg->erase_count);
+    LFS_ASSERT(off  % bd->cfg->prog_size == 0);
+    LFS_ASSERT(size % bd->cfg->prog_size == 0);
+    LFS_ASSERT(off+size <= bd->cfg->erase_size);
+
+    // program data
+    memcpy(&bd->buffer[block*bd->cfg->erase_size + off], buffer, size);
+
+    LFS_RAMBD_TRACE("lfs_rambd_prog -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_erase(const struct lfs_config *cfg, lfs_block_t block) {
+    LFS_RAMBD_TRACE("lfs_rambd_erase(%p, 0x%"PRIx32" (%"PRIu32"))",
+            (void*)cfg, block, ((lfs_rambd_t*)cfg->context)->cfg->erase_size);
+    lfs_rambd_t *bd = cfg->context;
+
+    // check if erase is valid
+    LFS_ASSERT(block < bd->cfg->erase_count);
+
+    // erase is a noop
+    (void)block;
+
+    LFS_RAMBD_TRACE("lfs_rambd_erase -> %d", 0);
+    return 0;
+}
+
+int lfs_rambd_sync(const struct lfs_config *cfg) {
+    LFS_RAMBD_TRACE("lfs_rambd_sync(%p)", (void*)cfg);
+
+    // sync is a noop
+    (void)cfg;
+
+    LFS_RAMBD_TRACE("lfs_rambd_sync -> %d", 0);
+    return 0;
+}