diff options
Diffstat (limited to 'Documentation/DocBook/mtdnand.tmpl')
| -rw-r--r-- | Documentation/DocBook/mtdnand.tmpl | 98 |
1 files changed, 36 insertions, 62 deletions
diff --git a/Documentation/DocBook/mtdnand.tmpl b/Documentation/DocBook/mtdnand.tmpl index 8e145857fc9..7da8f0402af 100644 --- a/Documentation/DocBook/mtdnand.tmpl +++ b/Documentation/DocBook/mtdnand.tmpl @@ -91,7 +91,7 @@ <listitem><para> [MTD Interface]</para><para> These functions provide the interface to the MTD kernel API. - They are not replacable and provide functionality + They are not replaceable and provide functionality which is complete hardware independent. </para></listitem> <listitem><para> @@ -100,14 +100,14 @@ </para></listitem> <listitem><para> [GENERIC]</para><para> - Generic functions are not replacable and provide functionality + Generic functions are not replaceable and provide functionality which is complete hardware independent. </para></listitem> <listitem><para> [DEFAULT]</para><para> Default functions provide hardware related functionality which is suitable for most of the implementations. These functions can be replaced by the - board driver if neccecary. Those functions are called via pointers in the + board driver if necessary. Those functions are called via pointers in the NAND chip description structure. The board driver can set the functions which should be replaced by board dependent functions before calling nand_scan(). If the function pointer is NULL on entry to nand_scan() then the pointer @@ -174,7 +174,7 @@ </para> <programlisting> static struct mtd_info *board_mtd; -static unsigned long baseaddr; +static void __iomem *baseaddr; </programlisting> <para> Static example @@ -182,15 +182,14 @@ static unsigned long baseaddr; <programlisting> static struct mtd_info board_mtd; static struct nand_chip board_chip; -static unsigned long baseaddr; +static void __iomem *baseaddr; </programlisting> </sect1> <sect1 id="Partition_defines"> <title>Partition defines</title> <para> If you want to divide your device into partitions, then - enable the configuration switch CONFIG_MTD_PARTITIONS and define - a partitioning scheme suitable to your board. + define a partitioning scheme suitable to your board. </para> <programlisting> #define NUM_PARTITIONS 2 @@ -250,7 +249,7 @@ static void board_hwcontrol(struct mtd_info *mtd, int cmd) <title>Device ready function</title> <para> If the hardware interface has the ready busy pin of the NAND chip connected to a - GPIO or other accesible I/O pin, this function is used to read back the state of the + GPIO or other accessible I/O pin, this function is used to read back the state of the pin. The function has no arguments and should return 0, if the device is busy (R/B pin is low) and 1, if the device is ready (R/B pin is high). If the hardware interface does not give access to the ready busy pin, then @@ -265,11 +264,11 @@ static void board_hwcontrol(struct mtd_info *mtd, int cmd) is set up nand_scan() is called. This function tries to detect and identify then chip. If a chip is found all the internal data fields are initialized accordingly. - The structure(s) have to be zeroed out first and then filled with the neccecary + The structure(s) have to be zeroed out first and then filled with the necessary information about the device. </para> <programlisting> -int __init board_init (void) +static int __init board_init (void) { struct nand_chip *this; int err = 0; @@ -283,8 +282,8 @@ int __init board_init (void) } /* map physical address */ - baseaddr = (unsigned long)ioremap(CHIP_PHYSICAL_ADDRESS, 1024); - if(!baseaddr){ + baseaddr = ioremap(CHIP_PHYSICAL_ADDRESS, 1024); + if (!baseaddr) { printk("Ioremap to access NAND chip failed\n"); err = -EIO; goto out_mtd; @@ -316,7 +315,7 @@ int __init board_init (void) goto out; out_ior: - iounmap((void *)baseaddr); + iounmap(baseaddr); out_mtd: kfree (board_mtd); out: @@ -328,7 +327,7 @@ module_init(board_init); <sect1 id="Exit_function"> <title>Exit function</title> <para> - The exit function is only neccecary if the driver is + The exit function is only necessary if the driver is compiled as a module. It releases all resources which are held by the chip driver and unregisters the partitions in the MTD layer. @@ -341,7 +340,7 @@ static void __exit board_cleanup (void) nand_release (board_mtd); /* unmap physical address */ - iounmap((void *)baseaddr); + iounmap(baseaddr); /* Free the MTD device structure */ kfree (board_mtd); @@ -362,7 +361,7 @@ module_exit(board_cleanup); <sect1 id="Multiple_chip_control"> <title>Multiple chip control</title> <para> - The nand driver can control chip arrays. Therefor the + The nand driver can control chip arrays. Therefore the board driver must provide an own select_chip function. This function must (de)select the requested chip. The function pointer in the nand_chip structure must @@ -485,17 +484,17 @@ static void board_select_chip (struct mtd_info *mtd, int chip) Reed-Solomon library. </para> <para> - The ECC bytes must be placed immidiately after the data + The ECC bytes must be placed immediately after the data bytes in order to make the syndrome generator work. This is contrary to the usual layout used by software ECC. The - seperation of data and out of band area is not longer + separation of data and out of band area is not longer possible. The nand driver code handles this layout and the remaining free bytes in the oob area are managed by the autoplacement code. Provide a matching oob-layout in this case. See rts_from4.c and diskonchip.c for implementation reference. In those cases we must also use bad block tables on FLASH, because the ECC layout is - interferring with the bad block marker positions. + interfering with the bad block marker positions. See bad block table support for details. </para> </sect2> @@ -543,7 +542,7 @@ static void board_select_chip (struct mtd_info *mtd, int chip) <para> nand_scan() calls the function nand_default_bbt(). nand_default_bbt() selects appropriate default - bad block table desriptors depending on the chip information + bad block table descriptors depending on the chip information which was retrieved by nand_scan(). </para> <para> @@ -555,25 +554,25 @@ static void board_select_chip (struct mtd_info *mtd, int chip) <sect2 id="Flash_based_tables"> <title>Flash based tables</title> <para> - It may be desired or neccecary to keep a bad block table in FLASH. + It may be desired or necessary to keep a bad block table in FLASH. For AG-AND chips this is mandatory, as they have no factory marked bad blocks. They have factory marked good blocks. The marker pattern is erased when the block is erased to be reused. So in case of powerloss before writing the pattern back to the chip this block - would be lost and added to the bad blocks. Therefor we scan the + would be lost and added to the bad blocks. Therefore we scan the chip(s) when we detect them the first time for good blocks and store this information in a bad block table before erasing any of the blocks. </para> <para> - The blocks in which the tables are stored are procteted against + The blocks in which the tables are stored are protected against accidental access by marking them bad in the memory bad block - table. The bad block table managment functions are allowed - to circumvernt this protection. + table. The bad block table management functions are allowed + to circumvent this protection. </para> <para> The simplest way to activate the FLASH based bad block table support - is to set the option NAND_USE_FLASH_BBT in the option field of + is to set the option NAND_BBT_USE_FLASH in the bbt_option field of the nand chip structure before calling nand_scan(). For AG-AND chips is this done by default. This activates the default FLASH based bad block table functionality @@ -593,7 +592,7 @@ static void board_select_chip (struct mtd_info *mtd, int chip) User defined tables are created by filling out a nand_bbt_descr structure and storing the pointer in the nand_chip structure member bbt_td before calling nand_scan(). - If a mirror table is neccecary a second structure must be + If a mirror table is necessary a second structure must be created and a pointer to this structure must be stored in bbt_md inside the nand_chip structure. If the bbt_md member is set to NULL then only the main table is used @@ -629,7 +628,7 @@ static void board_select_chip (struct mtd_info *mtd, int chip) holds the bad block table. Store a pointer to the pattern in the pattern field. Further the length of the pattern has to be stored in len and the offset in the spare area must be given - in the offs member of the nand_bbt_descr stucture. For mirrored + in the offs member of the nand_bbt_descr structure. For mirrored bad block tables different patterns are mandatory.</para></listitem> <listitem><para>Table creation</para> <para>Set the option NAND_BBT_CREATE to enable the table creation @@ -648,7 +647,7 @@ static void board_select_chip (struct mtd_info *mtd, int chip) <listitem><para>Table version control</para> <para>Set the option NAND_BBT_VERSION to enable the table version control. It's highly recommended to enable this for mirrored tables with write - support. It makes sure that the risk of loosing the bad block + support. It makes sure that the risk of losing the bad block table information is reduced to the loss of the information about the one worn out block which should be marked bad. The version is stored in 4 consecutive bytes in the spare area of the device. The position of @@ -667,7 +666,7 @@ static void board_select_chip (struct mtd_info *mtd, int chip) <para> For automatic placement some blocks must be reserved for bad block table storage. The number of reserved blocks is defined - in the maxblocks member of the babd block table description structure. + in the maxblocks member of the bad block table description structure. Reserving 4 blocks for mirrored tables should be a reasonable number. This also limits the number of blocks which are scanned for the bad block table ident pattern. @@ -774,20 +773,6 @@ struct nand_oobinfo { done according to the default builtin scheme. </para> </sect2> - <sect2 id="User_space_placement_selection"> - <title>User space placement selection</title> - <para> - All non ecc functions like mtd->read and mtd->write use an internal - structure, which can be set by an ioctl. This structure is preset - to the autoplacement default. - <programlisting> - ioctl (fd, MEMSETOOBSEL, oobsel); - </programlisting> - oobsel is a pointer to a user supplied structure of type - nand_oobconfig. The contents of this structure must match the - criteria of the filesystem, which will be used. See an example in utils/nandwrite.c. - </para> - </sect2> </sect1> <sect1 id="Spare_area_autoplacement_default"> <title>Spare area autoplacement default schemes</title> @@ -1060,19 +1045,19 @@ data in this page</entry> <row> <entry>0x3D</entry> <entry>ECC byte 21</entry> -<entry>Error correction code byte 0 of the eigth 256 Bytes of data +<entry>Error correction code byte 0 of the eighth 256 Bytes of data in this page</entry> </row> <row> <entry>0x3E</entry> <entry>ECC byte 22</entry> -<entry>Error correction code byte 1 of the eigth 256 Bytes of data +<entry>Error correction code byte 1 of the eighth 256 Bytes of data in this page</entry> </row> <row> <entry>0x3F</entry> <entry>ECC byte 23</entry> -<entry>Error correction code byte 2 of the eigth 256 Bytes of data +<entry>Error correction code byte 2 of the eighth 256 Bytes of data in this page</entry> </row> </tbody></tgroup></informaltable> @@ -1083,18 +1068,18 @@ in this page</entry> <chapter id="filesystems"> <title>Filesystem support</title> <para> - The NAND driver provides all neccecary functions for a + The NAND driver provides all necessary functions for a filesystem via the MTD interface. </para> <para> - Filesystems must be aware of the NAND pecularities and + Filesystems must be aware of the NAND peculiarities and restrictions. One major restrictions of NAND Flash is, that you cannot write as often as you want to a page. The consecutive writes to a page, before erasing it again, are restricted to 1-3 writes, depending on the manufacturers specifications. This applies similar to the spare area. </para> <para> - Therefor NAND aware filesystems must either write in page size chunks + Therefore NAND aware filesystems must either write in page size chunks or hold a writebuffer to collect smaller writes until they sum up to pagesize. Available NAND aware filesystems: JFFS2, YAFFS. </para> @@ -1134,8 +1119,6 @@ in this page</entry> These constants are defined in nand.h. They are ored together to describe the chip functionality. <programlisting> -/* Chip can not auto increment pages */ -#define NAND_NO_AUTOINCR 0x00000001 /* Buswitdh is 16 bit */ #define NAND_BUSWIDTH_16 0x00000002 /* Device supports partial programming without padding */ @@ -1159,9 +1142,6 @@ in this page</entry> These constants are defined in nand.h. They are ored together to describe the functionality. <programlisting> -/* Use a flash based bad block table. This option is parsed by the - * default bad block table function (nand_default_bbt). */ -#define NAND_USE_FLASH_BBT 0x00010000 /* The hw ecc generator provides a syndrome instead a ecc value on read * This can only work if we have the ecc bytes directly behind the * data bytes. Applies for DOC and AG-AND Renesas HW Reed Solomon generators */ @@ -1236,19 +1216,13 @@ in this page</entry> #define NAND_BBT_LASTBLOCK 0x00000010 /* The bbt is at the given page, else we must scan for the bbt */ #define NAND_BBT_ABSPAGE 0x00000020 -/* The bbt is at the given page, else we must scan for the bbt */ -#define NAND_BBT_SEARCH 0x00000040 /* bbt is stored per chip on multichip devices */ #define NAND_BBT_PERCHIP 0x00000080 /* bbt has a version counter at offset veroffs */ #define NAND_BBT_VERSION 0x00000100 /* Create a bbt if none axists */ #define NAND_BBT_CREATE 0x00000200 -/* Search good / bad pattern through all pages of a block */ -#define NAND_BBT_SCANALLPAGES 0x00000400 -/* Scan block empty during good / bad block scan */ -#define NAND_BBT_SCANEMPTY 0x00000800 -/* Write bbt if neccecary */ +/* Write bbt if necessary */ #define NAND_BBT_WRITE 0x00001000 /* Read and write back block contents when writing bbt */ #define NAND_BBT_SAVECONTENT 0x00002000 |