fs: Adds diskio interface

Adds the diskio interface for the FAT file system.  This
revision uses RAM to emulate disk storage.

Origin: Original
Jira: ZEP-285
Change-Id: I7a30c8761d5ed9b564f1d1e08482c5ef199d7372
Signed-off-by: Ramesh Thomas <ramesh.thomas@intel.com>

3 files changed, 139 insertions, 0 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
new file mode 100644
index 000000000..b958a930c
--- /dev/null
+++ b/fs/Kconfig
@@ -0,0 +1,67 @@
+#
+# Copyright (c) 2016 Intel Corporation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+menu "File System"
+
+config FILE_SYSTEM
+	bool "File system support"
+	default n
+	help
+	Enables support for file system.
+
+config FILE_SYSTEM_FAT
+	bool "FAT file system support"
+	default y
+	depends on FILE_SYSTEM
+	help
+	Enables FAT file system support.
+
+choice
+	prompt "Select file system storage device"
+	depends on FILE_SYSTEM_FAT
+	default FS_FAT_RAM_DISK
+	help
+	The storage device where the file system
+	resides
+
+config FS_FAT_RAM_DISK
+	bool
+	prompt "RAM Disk"
+	help
+	RAM buffer used to emulate storage disk.
+	This option can used to test the file
+	system.
+
+endchoice
+
+if FS_FAT_RAM_DISK
+
+config FS_VOLUME_SIZE
+	hex
+	default 0x18000
+	help
+	This is the file system volume size in bytes.
+
+config FS_BLOCK_SIZE
+	hex
+	default 0x1000
+	help
+	This is typically the minimum block size that
+	is erased at one time in flash storage.
+
+endif # FS_RAM_DISK
+
+endmenu
diff --git a/fs/Makefile b/fs/Makefile
new file mode 100644
index 000000000..4e618c7c0
--- /dev/null
+++ b/fs/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_FS_FAT_RAM_DISK) += fat_ram_diskio.o
diff --git a/fs/fat_ram_diskio.c b/fs/fat_ram_diskio.c
new file mode 100644
index 000000000..565e30378
--- /dev/null
+++ b/fs/fat_ram_diskio.c
@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2016 Intel Corporation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+#include <stdint.h>
+#include <misc/__assert.h>
+#include <diskio.h>
+#include <ff.h>
+
+static uint8_t file_buff[CONFIG_FS_VOLUME_SIZE];
+
+static void *lba_to_address(uint32_t lba)
+{
+	__ASSERT(((lba * _MIN_SS) < CONFIG_FS_VOLUME_SIZE), "FS bound error");
+	return &file_buff[(lba * _MIN_SS)];
+}
+
+DSTATUS fat_disk_status(void)
+{
+	return RES_OK;
+}
+
+DSTATUS fat_disk_initialize(void)
+{
+	return RES_OK;
+}
+
+DRESULT fat_disk_read(void *buff, uint32_t sector, uint32_t count)
+{
+	memcpy(buff, lba_to_address(sector), count * _MIN_SS);
+
+	return RES_OK;
+}
+
+DRESULT fat_disk_write(void *buff, uint32_t sector, uint32_t count)
+{
+	memcpy(lba_to_address(sector), buff, count * _MIN_SS);
+
+	return RES_OK;
+}
+
+DRESULT fat_disk_ioctl(uint8_t cmd, void *buff)
+{
+	switch (cmd) {
+	case CTRL_SYNC:
+		return RES_OK;
+	case GET_SECTOR_COUNT:
+		*(uint32_t *) buff = CONFIG_FS_VOLUME_SIZE / _MIN_SS;
+		return RES_OK;
+	case GET_BLOCK_SIZE:
+		*(uint32_t *) buff = CONFIG_FS_BLOCK_SIZE / _MIN_SS;
+		return RES_OK;
+	case CTRL_TRIM:
+		break;
+	}
+
+	return RES_PARERR;
+}