--- linux-2.6.24.7.old/README-JZ 1970-01-01 01:00:00.000000000 +0100 +++ linux-2.6.24.7/README-JZ 2009-04-12 18:13:57.000000000 +0200 @@ -0,0 +1,1181 @@ + + Linux 2.6 Kernel Release for Ingenic + + (Updated: 2008-12-29) + +------------- +** Content ** +------------- + +** Quick start ** +** Supported SOC and Platforms ** +** Overview of source tree ** +** NAND Flash Filesystem ** +** UBI, UBIFS and UBI Block Layer ** +** UBI and UBIFS images ** +** YAFFS2 ** +** MTD Block Layer ** +** About Bad Blocks of NAND ** +** SLC and MLC NAND Flash ** +** Initramfs ** +** Audio full duplex mode ** +** Support ** + + +----------------- +** Quick Start ** +----------------- + +To build linux 2.6, you needs a mipsel-linux-gcc version 4. Please +download it from Ingenic website http://www.ingenic.cn. + +You should have downloaded the linux-2.6.24.3.tar.bz2 and the latest kernel +patch. The patch file was named as "linux-2.6.24.3-jz-yyyymmdd.patch.gz". + +Follow next steps to install the full kernel source: + + $ tar -xjf linux-2.6.24.3.tar.bz2 + $ cd linux-2.6.24.3 + $ gzip -cd ../linux-2.6.24.3-jz-yyyymmdd.patch.gz | patch -p1 + +Now you can configure and build the kernel. + +First, you need to do a 'make board_defconfig' to select a board. + +For example: + + - make pavo_defconfig # JZ4740 PAVO board default configuration + - make pmp_defconfig # JZ4730 PMP ver 2.x board default configuration + - make dipper_defconfig # JZ4725 PMP ver 1.x board default configuration + +Then, configure and compile the kernel: + + - make xconfig or make menuconfig, if you want to change the configuration. + - make, make uImage, or make zImage, to build the kernel. + +The ELF format kernel image is linux-2.6.24.3/vmlinux. +The U-Boot format kernel image is linux-2.6.24.3/arch/mips/boot/uImage. +The compressed raw kernel image is linux-2.6.24.3/arch/mips/boot/compressed/zImage. + + +--------------------------------- +** Supported SOC and Platforms ** +--------------------------------- + +This release supports several platforms based on JZ4730, JZ4740 and JZ4750. + +JZ4750 based platforms: + + - apus: JZ4750 development board + +JZ4740 based platforms: + + - pavo: JZ4740 reference board + - leo: JZ4740 development board + +JZ4730 based platforms: + + - pmp: JZ4730 reference board version 2.x + +JZ4725 based platforms: + + - dipper: JZ4725 reference board version 1.x + + +----------------------------- +** Overview of source tree ** +----------------------------- + + - Changelog : Revision history + - README-JZ : This file + - arch/mips/ + - kernel/ : MIPS kernel common code + - mm/ : MIPS memory common code + - jz4730/ : JZ4730 code + - jz4740/ : JZ4740 JZ4725 JZ4720 code + - jz4750/ : JZ4750 code + - configs/ + - apus_defconfig : jz4750 based apus default configuration + - pavo_defconfig : jz4740 based pavo default configuration + - pmp_defconfig : jz4730 based pmp default configuration + - dipper_defconfig : jz4725 based dipper default configuration + - include/asm-mips/ : MIPS asm common include + - jzsoc.h : JZ SoC common include + - mach-jz4730/ : JZ4730 SoC headers + - mach-jz4740/ : JZ4740 JZ4725 JZ4720 SoC headers + - mach-jz4750/ : JZ4750 SoC headers + - fs/ + - jffs2/ : JFFS2 file system + - yaffs2/ : YAFFS2 file system + - utils/ : YAFFS2 utilities, like mkyaffs2image + - ubifs/ : ubifs file system + - mkfs.ubifs/ : mkfs.ubifs util to create UBIFS + - sound/ + oss/ : OSS audio driver + soc/jz4740/ : JZ4740 ALSA audio driver + - drivers/ + - char/ + - serial.c : serial port driver + - rtc_pcf8563.c : PCF8563 RTC driver + - rtc_jz.c : JZSOC On-Chip RTC driver + - jzchar/ : jzchar devices + - jz_ts.c : generic touch screen driver + - sadc.c : JZ4740 SADC driver + - ak4182.c : AK4182 touch driver + - udc_hotplug.c : UDC hotplug management + - poweroff.c : suspend/poweroff management + - input/keyboard/ + - jz_keypad.c : scan keypad driver + - gpio_keys.c : gpio keypad driver + - media/video/ + - jz_cim.c : generic camera driver + - jz_sensor.c : generic sensor driver + - mmc/host/ + - jz_mmc.c : jz mmc/sd card driver + - mtd/ + - mtdblock-jz.c : NAND Flash translation layer driver + - nand/ + - nand_base.c : NAND flash interface to MTD + - jz4730_nand.c : NAND flash definition on JZ4730 boards + - jz4740_nand.c : NAND flash definition on JZ4740 boards + - jz4750_nand.c : NAND flash definition on JZ4750 boards + - ubi/ : MTD utilities like flash_eraseall, nandwrite etc. + - ubiblk.c : UBI block layer driver on top of UBI + - mtd-utils/ : MTD and UBI utilities, like flash_eraseall, nandwrite and ubimkvol etc. + - ubi-utils : UBI utils like ubimkvol/ubirmvol/ubinize etc. + - net/ + - jz_eth.c : JZ4730 On-Chip ethernet driver + - jzcs8900a.c : cs8900a ethernet driver + - serial/ + - 8250.c : standard 16550A serial driver + - usb/ : USB OHCI host driver + - usb/host/ + ohci-jz.c : JZ OHCI driver + - usb/gadget/ + - jz4730_udc.c : JZ4730 UDC low-level driver + - jz4740_udc.c : JZ4740 and JZ4750 UDC low-level driver + - file_storage.c : USB mass storage class driver + - serial.c : USB serial class driver + - video/ + - jzlcd.c : JZ LCD controller framebuffer driver for JZ4730 and JZ4740 + - jz4740_slcd.c : JZ Smart LCD controller framebuffer driver for JZ4740 + - jz4750_lcd.c : JZ LCD and Smart LCD controller driver for JZ4750 + - jz4750_tve.c : JZ TV encoder controller driver for JZ4750 + - watchdog/ + - jz_wdt.c : JZ On-Chip watchdog driver + + +--------------------------- +** NAND Flash Filesystem ** +--------------------------- + +NAND Flash is the main non-volatile storage for most embedded devices. +So, it's very important to implement a stable and reasonable filesystem on +NAND flash. + +In Linux, the MTD subsystem provides a common interface for operating with +many flash devices, such as NOR, NAND etc. And the MTD subsystem was modified +by Ingenic to support the NAND larger than 2GB. + +Above MTD layer, we can implement the YAFFS2 filesystem. Or we can implement +a MTD block device, on top of it we can implement the general filesystem +such as FAT and EXT2. + +The Linux 2.6 kernel also implements the UBI (Unsorted Block Images). UBI +is a software layer above MTD layer which admits of LVM-like logical volumes +on top of MTD devices, hides some complexities of flash chips like wear +and bad blocks and provides some other useful capabilities. Please, consult +the MTD web site for more details (www.linux-mtd.infradead.org). + +On top of UBI, we can implement the UBIFS filesystem. We can also emulate +block devices above UBI, such that we can use the general filesystem such as +FAT and EXT2 on it. + +The architecture of the NAND flash filesystem is illustrated as below: + + + + +-----------+ +-------------+ +-------------+ + | YAFFS2 | | UBIFS | | FAT or EXT2 | Filesystems + +-----------+ +-------------+ +-------------+ + \ | / \ + \ | / \ + \ | / \ + \ | +-----------------+ +-----------------+ + \ | | UBI Block Layer | | MTD Block Layer | + \ | +-----------------+ +-----------------+ + \ | / / + \ | / / + \ +-------------+ / + \ | UBI | / + \ +-------------+ / + \ | / + +-------------------------------------------+ + | MTD | + +-------------------------------------------+ + | + +--------------------+ + | nand_base.c | + +--------------------+ + | + +--------------------+ + | jz4740_nand.c | + +--------------------+ + + +The related source codes are listed below: + +fs/yaffs2: YAFFS2 +fs/ubifs: UBIFS +fs/fat: FAT +fs/ext2: EXT2 +drivers/mtd: MTD +drivers/mtd/ubi: UBI +drivers/mtd/ubi/ubiblk.c: UBI Block Layer +drivers/mtd/mtdblock-jz.c: MTD Block Layer +drivers/mtd/mtd-utils: MTD and UBI utils (flash_eraseall/ubimkvol/ubinfo/ubinize etc.) +fs/ubifs/mkfs.ubifs: UBIFS util to create ubifs image (mkfs.ubifs) +fs/yaffs2/util: YAFFS2 util (mkyaffs2image) + +To build mtd utils, go to drivers/mtd/mtd-utils, type 'make' and +'make install DESTDIR=/nfsroot/root26'. + +To build yaffs2 util, go to fs/yaffs2/utils and type 'make'. + +To build ubifs util, go to fs/ubifs/mkfs.ubifs and type 'make'. + +Except 'UBI Block Layer' and 'MTD Block Layer', which are implement by Ingenic +ourself, the others are general in the linux kernel tree. + +User can select any one of these drivers to implement the filesystem. It all +depends on yourself. + +Following sections will describe how to use these drivers in details. + + +------------------------------------ +** UBI, UBIFS and UBI Block Layer ** +------------------------------------ + +UBIFS is a new flash file system which is designed to work on top of UBI. + +Here is a short and unsorted list of some of UBIFS features: + +* write-back support - This dramatically improves the throughput of the +file-system comparing to JFFS2, which is write-through; + +* fast mount time + +* tolerance to unclean reboots - UBIFS is a journaling file system and it +tolerates sudden crashes and unclean reboots; + +* fast I/O - even with write-back disabled; + +* on-the-flight compression - the data is stored in compressed form on +the flash media, which makes it possible to put considerably more data to +the flash as if the data would not be compressed; + +Please, consult the MTD web site for more details (www.linux-mtd.infradead.org). + +The UBI and UBIFS can be compiled as modules or built into the kernel. + +To enable UBI, you need to select following configurations: + +CONFIG_MTD_UBI: Enable UBI +CONFIG_MTD_UBI_WL_THRESHOLD: UBI wear-leveling threshold +CONFIG_MTD_UBI_BEB_RESERVE: Percentage of reserved eraseblocks for bad eraseblocks handling + +To enable 'UBI Block Layer', you need to select following configurations: + +CONFIG_MTD_UBI_BLKDEVS: Common interface to block layer for UBI +CONFIG_MTD_UBI_BLOCK: Emulate block devices + +To enable UBIFS, you need to select following configurations: + +CONFIG_UBIFS_FS: UBIFS file system support +CONFIG_UBIFS_COMPRESSION_OPTIONS: Advanced compression options for UBIFS +CONFIG_UBIFS_LZO: UBIFS LZO compression support +CONFIG_UBIFS_ZLIB: UBIFS ZLIB compression support +CONFIG_UBIFS_FS_DEBUG: UBIFS debugging + +If you want to compile as modules, take next steps: + +Type 'make modules' to compile the modules. + +Type 'make modules_install INSTALL_MOD_PATH=/nfsroot/root26' to install the +modules to the target root. + +You also need to compile the MTD and UBIFS utilities and install them to the +target root. + + +Now boot your board and mounted root FS with these modules, and below is a +simple guide to test and use the UBIFS and 'UBI Block Layer': + +Here we will create UBI volumes on mtd5. + +First, format mtd5: + +# flash_eraseall /dev/mtd5 +Erasing 256 Kibyte @ 1ffc0000 -- 99 % complete. + +Install UBI module, attached it to mtd5: + +# modprobe ubi mtd=5 +UBI: empty MTD device detected +UBI: create volume table (copy #1) +UBI: create volume table (copy #2) +UBI: attached mtd5 to ubi0 +UBI: MTD device name: "NAND VFAT partition" +UBI: MTD device size: 512 MiB +UBI: physical eraseblock size: 262144 bytes (256 KiB) +UBI: logical eraseblock size: 258048 bytes +UBI: number of good PEBs: 2048 +UBI: number of bad PEBs: 0 +UBI: smallest flash I/O unit: 2048 +UBI: VID header offset: 2048 (aligned 2048) +UBI: data offset: 4096 +UBI: max. allowed volumes: 128 +UBI: wear-leveling threshold: 4096 +UBI: number of internal volumes: 1 +UBI: number of user volumes: 0 +UBI: available PEBs: 2024 +UBI: total number of reserved PEBs: 24 +UBI: number of PEBs reserved for bad PEB handling: 20 +UBI: max/mean erase counter: 0/0 +UBI: background thread "ubi_bgt0d" started, PID 241 + +Now, create two UBI volumes, one is called ubifs and size is 200MB, the +other is called vfat and size is 298MB. + +# ubimkvol /dev/ubi0 -s 200MiB -N ubifs +Volume ID 0, size 813 LEBs (209793024 bytes, 200.1 MiB), LEB size 258048 bytes (252.0 KiB), dynamic, name "ubifs", alignment 1 +# ubimkvol /dev/ubi0 -s 298MiB -N vfat +Volume ID 1, size 1211 LEBs (312496128 bytes, 298.0 MiB), LEB size 258048 bytes (252.0 KiB), dynamic, name "vfat", alignment 1 + +Then you can use 'ubinfo' to query the UBI volume info: + +# ubinfo -a +UBI version: 1 +Count of UBI devices: 1 +UBI control device major/minor: 10:63 +Present UBI devices: ubi0 + +ubi0: +Volumes count: 2 +Logical eraseblock size: 258048 +Total amount of logical eraseblocks: 2048 (528482304 bytes, 504.0 MiB) +Amount of available logical eraseblocks: 0 (0 bytes) +Maximum count of volumes 128 +Count of bad physical eraseblocks: 0 +Count of reserved physical eraseblocks: 20 +Current maximum erase counter value: 3 +Minimum input/output unit size: 2048 bytes +Character device major/minor: 252:0 +Present volumes: 0, 1 + +Volume ID: 0 (on ubi0) +Type: dynamic +Alignment: 1 +Size: 813 LEBs (209793024 bytes, 200.1 MiB) +State: OK +Name: ubifs +Character device major/minor: 252:1 +----------------------------------- +Volume ID: 1 (on ubi0) +Type: dynamic +Alignment: 1 +Size: 1211 LEBs (312496128 bytes, 298.0 MiB) +State: OK +Name: vfat +Character device major/minor: 252:2 + + +It shows that we have successfully created two UBI volumes (Volume ID 0 and 1) +on ubi0. + +Now you can install the UBIFS and 'UBI Block Layer' modules and create +UBIFS and FAT on UBI volume 0 and 1 respectively. + +# modprobe ubifs +# modprobe ubiblk + +# lsmod +Module Size Used by Not tainted +ubiblk 7696 0 +bdev 10016 1 ubiblk +deflate 4256 1 +zlib_deflate 22256 1 deflate +zlib_inflate 16992 1 deflate +lzo 2400 1 +lzo_decompress 2816 1 lzo +lzo_compress 2848 1 lzo +ubifs 208560 0 +crc16 2048 1 ubifs +ubi 103664 4 ubiblk,bdev,ubifs + +Mount UBI volume 0 (the name is "ubifs") on ubi0 with type ubifs: + +# mount -t ubifs ubi0:ubifs /mnt/ubifs/ +UBIFS: mounted UBI device 0, volume 0 +UBIFS: minimal I/O unit size: 2048 bytes +UBIFS: logical eraseblock size: 258048 bytes (252 KiB) +UBIFS: file system size: 207212544 bytes (202356 KiB, 197 MiB, 803 LEBs) +UBIFS: journal size: 9420800 bytes (9200 KiB, 8 MiB, 37 LEBs) +UBIFS: data journal heads: 1 +UBIFS: default compressor: LZO + +It shows that we have mounted it sucessfully. + +Format /dev/ubiblock1 (the block device for UBI volume 1) and mount it with +type vfat: + +# mkfs.vfat /dev/ubiblock1 +# mount -t vfat /dev/ubiblock1 /mnt/ubiblock1 + +Please refer to the linux26_developer_guide.pdf for more details about +the UBI and UBIFS. + + +-------------------------- +** UBI and UBIFS images ** +-------------------------- + +Generally, you want to create UBIFS and VFAT images respectively and combine +these two images into one single image, and then use the nandwrite command +to write this image to the MTD partition. + +First of all, you need to compile the mkfs.ubifs utility. We use mkfs.ubifs +to create the UBIFS image, like this: + +Note: download the linux-nand-utils.tar.gz package from www.ingenic.cn and +follows the guide to compile and run the mkfs.ubifs. + +On the PC host: + +$ mkfs.ubifs -h +Usage: mkfs.ubifs [OPTIONS] +Make a UBIFS file system image from an existing directory tree + +Options: + -r, -d, --root=DIR Build file system from directory DIR + -m, --min-io-size=SIZE Minimum I/O size SIZE + -e, --leb-size=SIZE Use logical erase block size SIZE + -c, --max-leb-cnt=COUNT Use maximum logical erase block count COUNT + -o, --output=FILE Output to FILE + -j, --jrn-size=SIZE Use journal size SIZE bytes + -x, --compr=TYPE Use compression type TYPE (lzo, zlib or none) (default: lzo) + -f, --fanout=NUM Use fanout NUM (default: 8) + -k, --keyhash=TYPE Use key hash type TYPE (r5 or test) (default: r5) + -l, --log-lebs=COUNT Use COUNT erase blocks for the log + -p, --orph-lebs=COUNT Use COUNT erase blocks for orphans (default: 1) + -v, --verbose Verbose operation + -V, --version Display version information + -g, --debug=LEVEL Display debug information + -h, --help Display this help text + +$ mkfs.ubifs -r /nfsroot/root26 -m 2048 -e 258048 -c 813 -o ubifs.img + +This will create an UBIFS image called ubifs.img. The argument values +can be obtained from the 'ubinfo -a' command. + +Follow next steps to create a 30MB FAT32 image called vfat.img: + +# dd if=/dev/zero of=vfat.img bs=1M count=30 +# losetup /dev/loop0 vfat.img +# mkfs.vfat /dev/loop0 +# mount -t vfat /dev/loop0 /mnt/vfat +# cp * /mnt/vfat +# umount /mnt/vfat +# losetup -d /dev/loop0 + +Now the two images ubifs.img and vfat.img are ready, and we want to +create two UBI volumes and write these two images to the two UBI volumes +respectively. We can do like this: + +First, use 'ubinize' command to combine ubifs.img and vfat.img into one +UBI image called ubi.img. + +Second, use 'nandwrite_mlc_ubi' command to write the ubi.img to the +MTD partition. + +To use 'ubinize' command, you should prepare an INI file for it. The +content of the INI file are as below: + +# cat ubinize.cfg +[ubifs] +mode=ubi +image=ubifs.img +vol_id=0 +vol_size=200MiB +vol_type=dynamic +vol_name=ubifs +vol_alignment=1 +vol_flag=autoresize + +[vfat] +mode=ubi +image=vfat.img +vol_id=1 +vol_size=298MiB +vol_type=dynamic +vol_name=vfat +vol_alignment=1 +vol_flag=autoresize + + +Now you can boot your board and follow next guides to create the UBI +image and burn the UBI image. + +On the target board side: + +# ubinize -o ubi.img ubinize.cfg -p 262144 -m 2048 + +If things go well, you can get the UBI image ubi.img. + +Then use 'nandwrite_ubi' command to write it to the MTD partition. + +# flash_eraseall /dev/mtd5 +# nandwrite_ubi -a -q -m /dev/mtd5 ubi.img + +Now the UBI image has been written to the NAND mtd5 partition. + +Use next commands to test it. + +# modprobe ubi mtd=5 + +# ubinfo -a +UBI version: 1 +Count of UBI devices: 1 +UBI control device major/minor: 10:63 +Present UBI devices: ubi0 + +ubi0: +Volumes count: 2 +Logical eraseblock size: 258048 +Total amount of logical eraseblocks: 2048 (528482304 bytes, 504.0 MiB) +Amount of available logical eraseblocks: 0 (0 bytes) +Maximum count of volumes 128 +Count of bad physical eraseblocks: 0 +Count of reserved physical eraseblocks: 20 +Current maximum erase counter value: 1 +Minimum input/output unit size: 2048 bytes +Character device major/minor: 252:0 +Present volumes: 0, 1 + +Volume ID: 0 (on ubi0) +Type: dynamic +Alignment: 1 +Size: 813 LEBs (209793024 bytes, 200.1 MiB) +State: OK +Name: ubifs +Character device major/minor: 252:1 +----------------------------------- +Volume ID: 1 (on ubi0) +Type: dynamic +Alignment: 1 +Size: 1211 LEBs (312496128 bytes, 298.0 MiB) +State: OK +Name: vfat +Character device major/minor: 252:2 + + +This shows that two UBI volumes are present on ubi0. + +# modprobe ubifs +# mount -t ubifs ubi0:ubifs /mnt/ubifs/ +UBIFS: mounted UBI device 0, volume 0 +UBIFS: minimal I/O unit size: 2048 bytes +UBIFS: logical eraseblock size: 258048 bytes (252 KiB) +UBIFS: file system size: 207212544 bytes (202356 KiB, 197 MiB, 803 LEBs) +UBIFS: journal size: 9420800 bytes (9200 KiB, 8 MiB, 37 LEBs) +UBIFS: data journal heads: 1 +UBIFS: default compressor: LZO + +# modprobe ubiblk +# mount -t vfat /dev/ubiblock1 /mnt/ubiblock1 + +# df +Filesystem 1k-blocks Used Available Use% Mounted on +tmpfs 30196 56 30140 0% /dev +ubi0:ubifs 197536 48228 149308 24% /mnt/ubifs +/dev/ubiblock1 30642 5762 24880 19% /mnt/ubiblock1 + +It shows that the UBIFS and VFAT are all mounted successfully. + + +------------ +** YAFFS2 ** +------------ + +YAFFS (Yet Another Flash File System) was written to satisfy the +special needs of NAND flash. The second release of YAFFS especially +points to supporting newer NAND flash chips with 2k page size and +up to 128MB capacity. + +YAFFS2 is supported in this kernel. It's built on top of MTD directly. +Go to fs/yaffs2 for more details. + +To build the utility of YAFFS2, change to directory fs/yaffs2/utils/ +and type 'make'. + +To create a YAFFS2 image, mkyaffs2image command is used On PC host: + + usage: mkyaffs2image layout# dir image_file [convert] + + layout# NAND OOB layout: + 0 - nand_oob_raw, no used, + 1 - nand_oob_64, for 2KB pagesize, + 2 - nand_oob_128, for 2KB pagesize using multiple planes or 4KB pagesize, + 3 - nand_oob_256, for 4KB pagesize using multiple planes + dir the directory tree to be converted + image_file the output file to hold the image + + e.g., for 2KB page size NAND not using multi-plane: + + $ mkyaffs2image 1 /nfsroot/root26 root26.yaffs2 + +To burn the yaffs2 image to the NAND, use next command (On target board): + + # nandwrite -a -o /dev/mtd2 root26.yaffs2 + +To format and mount YAFFS2 (On target board): + + # flash_eraseall /dev/mtd2 + # mount -t yaffs2 /dev/mtdblock2 /mnt/mtdblock2 + + +--------------------- +** MTD Block Layer ** +--------------------- + +Ingenic implement the 'MTD Block Layer' by ourself. This gives you a choice +to implement a general filesystem such as FAT and ext2 on NAND flash. + +Which partition used for VFAT should be set in bootargs of u-boot for kernel cmdline, +so the kernel kowns other partitions aren't base on MTD Block Layer, and their mounting +speed will be faster. For example, if mtdblock5 is used for VFAT, you can + +set bootargs mem=64M console=ttyS1,57600n8 ip=dhcp root=/dev/mtdblock2 rw mtdblk=5 + +and the mounting speed of mtdblock2 which is not based on MTD Block Layer will be faster. + + +Features of the 'MTD Block Layer' include: + +1. Block unit management (address mapping & block cache operations) +2. Wear-leveling +3. Bad block management +4. Write verify enable +5. mutiple choice of ECC algorithms (hardware Hamming ECC & Reed Solomon ECC, +software Hamming ECC) + +Kernel configurations related to the 'MTD Block Layer': + +* CONFIG_MTD_OOB_COPIES: defines how many copies of the critical oob data for + each block. Since the page data can be corrected by the ECC algorithm but + the oob data can't, we want to ensure the correction of the oob data by this + way. The mtdblock-jz translation layer driver uses block mode to manipulate + the NAND flash. It makes several copies of the oobinfo data for each block, + so that it can get a correct copy even there is an error in one of them. + +* CONFIG_MTD_MTDBLOCK_WRITE_VERIFY_ENABLE: defines this to enable the write + verification function, which will read back data to verify during a write + operation. + +Take following steps to use the 'MTD Block Layer': + + # flash_eraseall /dev/mtd3 + # mkfs.vfat /dev/mtdblock3 + # mount -t vfat /dev/mtdblock3 /mnt/vfat + + +NOTICE: + +You can define mutiple VFAT partitions, all the VFAT partitions share +the same above configurations. + +Each VFAT partition have its own block cache which resides only in RAM. +Generally, the block cache flush operation is triggered when the access +address exceeds block boundary. The last block cache usually will be +flushed to NAND device when the device is closed (eg: umount /mnt/vfat; +use system call close(fd)). + +Abrupt poweroff without flushing the last block cache will cause the +VFAT partition to lose the most significant data which records the +information of the file system management such as FAT table, inodes ... + +To avoid this bad thing, you have to flush block cache as soon as possible. +Please do remember to flush block cache manually when you finish +a write operation. + +The MTD block layer driver supplys an ioctl for triggering flush block cache +operation. The code attached behind is a reference for you to use. + +eg: + + # cp * /mnt/vfat + # sync ; this step is necessary to flush the FS cache + # flushcache /dev/mtdblock3 ; this step is necessary to flush the NFTL block cache + + +/* flushcache.c */ +#include +#include +#include +#include + +int main(int argc,char **argv) +{ + int fd; + + if( argc != 2 ){ + printf( "Usage:%s device name(full path)\n", argv[0] ); + return -1; + } + + if( (fd = open( argv[1], O_RDONLY ) ) == -1) { + printf( "Open %s failed\n", argv[1] ); + return -1; + } + + if( ioctl( fd, BLKFLSBUF) == -1) + printf("flush catche failed\n"); + + close(fd); + return 0; +} + + +------------------------------ +** About Bad Blocks of NAND ** +------------------------------ + +NAND is a special flash type which there are new bad blocks generated during +the whole period of using it. So the NAND driver should know how to detect +a bad block and how to mark a new block bad. + +Some types of NAND flash mark the bad block in the spare area of the first +page but others in the last page. So we define a kernel configuration called +CONFIG_MTD_BADBLOCK_FLAG_PAGE and use it to decide the bad block. + +CONFIG_MTD_BADBLOCK_FLAG_PAGE: page in a block to store the badblock mark + +Following functions should be cared: + +nand_base.c: + + - nand_block_bad() + - nand_default_block_markbad() + +nand_bbt.c: + + - create_bbt() + +--------------------------------------- +** Multiple plane operation for NAND ** +--------------------------------------- + +NAND multiple plane is a feature enabling support of simultaneous write/erase +operations for NAND devices with multiplane architecture. This feature +significantly increases write performance. It could give performance benefits +if NAND device supports ultiple plane architecture only. If NAND device does +not support multiple plane and CONFIG_MTD_NAND_MULTI_PLANE was set to yes when +compiling kernel, code will parse device capabilities and NAND device will work +in single plane mode. For safe, you'd better set CONFIG_MTD_NAND_MULTI_PLANE to +no if NAND device does not support multiple plane. + +If the NAND device support multiple plane, you could determine which partitions +use multiple plane and which use single plane by setting the value of +partition_info[] in driver/mtd/nand/jz47xx_nand.c, if the value of use_planes +for a partition is 0, then the partition uses single plane, or else it uses +multiple plane. e.g. + +static struct mtd_partition partition_info[] = { + {name:"NAND BOOT partition", + offset:0 * 0x100000, + size:4 * 0x100000, + use_planes: 0}, + {name:"NAND KERNEL partition", + offset:4 * 0x100000, + size:4 * 0x100000, + use_planes: 0}, + {name:"NAND ROOTFS partition", + offset:8 * 0x100000, + size:120 * 0x100000, + use_planes: 1}, + {name:"NAND DATA1 partition", + offset:128 * 0x100000, + size:128 * 0x100000, + use_planes: 1}, + {name:"NAND DATA2 partition", + offset:256 * 0x100000, + size:256 * 0x100000, + use_planes: 1}, + {name:"NAND VFAT partition", + offset:512 * 0x100000, + size:512 * 0x100000, + use_planes: 1}, +}; + +--------------------------------------- +** Multiple chip selecting for NAND ** +--------------------------------------- + +CS1_N pin on Jz4740 or Jz4750 will be used for NAND defaultly; besides CS2_N, +CS3_N, and CS4_N pins could be used for NAND, too. You can configure the kernel +and select the configuration at: + + [Memory Technology Devices (MTD)] --> [NAND Device Support] + + --> [ECC Type] --> [Use NAND on CS2_N of JZSOC] + [Use NAND on CS3_N of JZSOC] + [Use NAND on CS4_N of JZSOC] + + +---------------------------- +** SLC and MLC NAND Flash ** +---------------------------- + +Single-Level Cell (SLC) and Multi-Level Cell (MLC) are both NAND-based +non-volatile memory technologies. MLC NAND Flash allows each memory cell +to store two bits of information, compared to the one bit-per-cell SLC +NAND Flash allows. As a result, 90 nanometer (nm) MLC NAND offers a +larger capacity (typically twice the density of SLC) and at a cost point +appropriate for consumer products. + +Though SLC NAND offers a lower density, it also provides an enhanced +level of performance in the form of faster write speeds. Because SLC +stores only one bit per cell, the likelihood for error is reduced. +At 90 nanometer process, it is recommended to implement a 1 to 2-bit +ECC for SLC, whereas 4-bit ECC is recommended on the MLC architecture. + +The linux kernel from ingenic provides MLC NAND support through Hardware +ECC algorithm. Jz4740 supports Reed-Solomon (RS) ECC algorithm, which can +detect and correct 4-bit errors per 512 bytes at least. Jz4750 supports +4-bit and 8-bit BCH ECC algorithm, 4-bit BCH ECC can detect and correct +4 bits for up to 1010 bytes and 8-bit BCH ECC can detect and correct +8 bits errors for up to 1016 bytes. + +To include MLC NAND support, you are required to configure the kernel +and select the configuration CONFIG_MTD_HW_RS_ECC for Jz4740, and +CONFIG_MTD_HW_BCH_ECC for Jz4750, which can be found at: + + [Memory Technology Devices (MTD)] --> [NAND Device Support] + + --> [ECC Type] --> [Select hardware RS ECC] + [Select hardware BCH ECC] + + +--------------- +** Initramfs ** +--------------- + +Please read Documentation/filesystems/ramfs-rootfs-initramfs.txt for +more information about how to use initramfs. + +Following are some steps to help you to create root fs by using initramfs: + +# cd /rootfs/ +# find . | cpio -c -o | gzip -9 > ../rootfs.cpio.gz + +Reconfigure the Linux kernel and select next configurations: + +CONFIG_BLK_DEV_INITRD=y +CONFIG_INITRAMFS_SOURCE="/rootfs.cpio.gz" +CONFIG_INITRAMFS_ROOT_UID=0 +CONFIG_INITRAMFS_ROOT_GID=0 + +Rebuild the kernel and boot the kernel with next command lines: + +"root=/dev/ram0 rw rdinit=/sbin/init" + + +---------------------------- +** Audio full duplex mode ** +---------------------------- + +OSS audio driver supports full duplex mode, that is to say, you can +record while replaying. + +The user application want to do some jobs to enable the full duplex mode +of the OSS driver. The following are two examples: + + +One is: + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define AUDIO_FILE "/dev/dsp" +#define FREQS 48000 +#define CHANNELS 2 +#define TEST_TIME 10 +#define SAMPLES 16 +#define BUF_SIZE 8192 +#define MAX_LEN (FREQS * CHANNELS * TEST_TIME * SAMPLES / 8) + +int main(int argc, char *argv[]) +{ + FILE *fp; + pid_t pid; + int audio_fd, i; + char *play_name; + char *rec_name; + + int play_count, play_cnt, played; + int rec_count, rec_cnt, recorded; + + u_char play_arr[MAX_LEN]; + u_char rec_arr[MAX_LEN]; + int err = 0; + + play_name = argv[1]; + rec_name = argv[2]; + + if ((audio_fd = open("/dev/dsp", O_RDWR)) < 0) { + printf(" Can't open sound device!\n"); + exit(-1); + } + + i = BUF_SIZE; + ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &i); + ioctl(audio_fd, SNDCTL_DSP_SYNC, NULL); + + i = CHANNELS; + ioctl(audio_fd, SNDCTL_DSP_STEREO, (u_char *) &i); + + i = SAMPLES; + ioctl(audio_fd, SNDCTL_DSP_SAMPLESIZE, (u_char *) &i); + + i = FREQS; + ioctl(audio_fd, SNDCTL_DSP_SPEED, (u_char *) &i); + + fp=fopen(play_name, "r"); + fread(play_arr, 1, MAX_LEN, fp); + fclose(fp); + + + play_count = MAX_LEN; + played = 0; + + rec_count = MAX_LEN; + recorded = 0; + + switch(pid = fork()) { + case -1: + printf("error\n"); + break; + case 0: + printf(" playing\n"); + while (play_count) { + play_cnt = play_count; + if (play_cnt > BUF_SIZE) + play_cnt = BUF_SIZE; + + write (audio_fd, (char *)play_arr+played, play_cnt); + played += play_cnt; + play_count -= play_cnt; + }/* while (count) */ + exit(0); + break; + default: + printf(" recording\n"); + while (rec_count) { + rec_cnt = rec_count; + if (rec_cnt > BUF_SIZE) + rec_cnt = BUF_SIZE; + + read (audio_fd, (char *)rec_arr+recorded, rec_cnt); + recorded += rec_cnt; + rec_count -= rec_cnt; + }/* while (count) */ + break; + } + close(audio_fd); + + printf("write data to file, waiting for a while\n"); + fp=fopen(rec_name, "w"); + fwrite(rec_arr, 1, MAX_LEN, fp); + fclose(fp); + + return err; +} + +The other is : + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define AUDIO_FILE "/dev/dsp" +#define FREQS_PLAY 22050 +#define FREQS_REC 8000 +#define FREQS 22050 +#define CHANNELS 1 +#define TEST_TIME 10 +#define SAMPLES 16 +#define BUF_SIZE 8192 +#define MAX_LEN (FREQS * CHANNELS * TEST_TIME * SAMPLES / 8) + +int main(int argc, char *argv[]) +{ + FILE *fp; + pid_t pid; + int audio_fd, i; + char *play_name; + char *rec_name1, *rec_name2, *rec_name3; + int mixerfd, vol, savevol; + + int count; + int play_count, play_cnt, played; + int rec_count, rec_cnt, recorded; + + u_char play_arr[MAX_LEN]; + u_char rec_arr[MAX_LEN]; + int err = 0; + + play_name = argv[1]; + rec_name1 = argv[2]; + rec_name2 = argv[3]; + rec_name3 = argv[4]; + + if ((mixerfd = open("/dev/mixer", O_RDWR)) < 0) { + perror("/dev/mixer"); + exit(1); + } + + if ((audio_fd = open("/dev/dsp", O_RDWR)) < 0) { + printf(" Can't open sound device!\n"); + exit(-1); + } + + i = BUF_SIZE; + ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &i);// midify buffer lenth + ioctl(audio_fd, SNDCTL_DSP_SYNC, NULL); + + i = CHANNELS; + ioctl(audio_fd, SNDCTL_DSP_CHANNELS, (u_char *) &i); + + i = SAMPLES; + ioctl(audio_fd, SNDCTL_DSP_SAMPLESIZE, (u_char *) &i); + + fp=fopen(play_name, "r"); + fread(play_arr, 1, MAX_LEN, fp); + fclose(fp); + + if (ioctl(mixerfd, SOUND_MIXER_READ_MIC, &savevol) == -1) { + perror("SOUND_MIXER_READ_DEVMASK mic"); + exit(-1); + } + + savevol = savevol & 0xff; + + for (count = 1; count <= 3; count++) { + + play_count = MAX_LEN; + played = 0; + + rec_count = MAX_LEN; + recorded = 0; + + + i = FREQS_PLAY; + ioctl(audio_fd, SNDCTL_DSP_SPEED, (u_char *) &i); + + printf(" playing %d\n", i); + while (play_count) { + play_cnt = play_count; + if (play_cnt > BUF_SIZE) + play_cnt = BUF_SIZE; + + write (audio_fd, (char *)play_arr+played, play_cnt); + played += play_cnt; + play_count -= play_cnt; + }/* while (count) */ + + /* wait for sync */ + ioctl(audio_fd, SNDCTL_DSP_SYNC, NULL); + + /* set mic gain 0 */ + vol = 0; + if (ioctl(mixerfd, SOUND_MIXER_WRITE_MIC, &vol) == -1) { + perror("SOUND_MIXER_WRITE_DEVMASK mic"); + exit(-1); + } + i = FREQS_REC; + ioctl(audio_fd, SNDCTL_DSP_SPEED, (u_char *) &i); + /* set mic gain orgin */ + vol = savevol; + if (ioctl(mixerfd, SOUND_MIXER_WRITE_MIC, &vol) == -1) { + perror("SOUND_MIXER_READ_DEVMASK mic"); + exit(-1); + } + + printf(" recording %d\n", i); + while (rec_count) { + rec_cnt = rec_count; + if (rec_cnt > BUF_SIZE) + rec_cnt = BUF_SIZE; + + read (audio_fd, (char *)rec_arr+recorded, rec_cnt); + recorded += rec_cnt; + rec_count -= rec_cnt; + }/* while (count) */ + + switch (count) { + case 1: + printf(" write to %s\n",rec_name1); + fp=fopen(rec_name1, "w"); + fwrite(rec_arr, 1, MAX_LEN, fp); + fclose(fp); + break; + case 2: + printf(" write to %s\n",rec_name2); + fp=fopen(rec_name2, "w"); + fwrite(rec_arr, 1, MAX_LEN, fp); + fclose(fp); + break; + case 3: + printf(" write to %s\n",rec_name3); + fp=fopen(rec_name3, "w"); + fwrite(rec_arr, 1, MAX_LEN, fp); + fclose(fp); + break; + } + sleep(1); + } + + close(audio_fd); + + return err; +} + +------------- +** Support ** +------------- + +Welcome to Ingenic website: + +More details, please refer to linux26_developer_guide.pdf.