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diff --git a/u-boot/doc/README.mflash b/u-boot/doc/README.mflash new file mode 100644 index 0000000..50133b4 --- /dev/null +++ b/u-boot/doc/README.mflash @@ -0,0 +1,94 @@ + +This document describes m[g]flash support in u-boot. + +Contents + 1. Overview + 2. Porting mflash driver + 3. Mflash command + 4. Misc. + +1. Overview +Mflash and gflash are embedded flash drive. The only difference is mflash is +MCP(Multi Chip Package) device. These two device operate exactly same way. +So the rest mflash repersents mflash and gflash altogether. + +2. Porting mflash driver + +2-1. Board configuration +* Mflash driver support +#define CONFIG_CMD_MG_DISK +#define CONFIG_LIBATA + +* Environment variable support (optional) +#define CONFIG_ENV_IS_IN_MG_DISK +Also CONFIG_ENV_ADDR and CONFIG_ENV_SIZE should be defined. +CONFIG_ENV_ADDR is byte offset starting from 0. + +Following example sets environment variable location to 0x80000 (1024'th +sector) and size of 0x400 (1024 byte) +#define CONFIG_ENV_ADDR 0x80000 +#define CONFIG_ENV_SIZE 0x400 + +* Reserved size config (optional) +If you want to use some reserved area for bootloader, environment variable or +whatever, use CONFIG_MG_DISK_RES. The unit is KB. Mflash's block operation +method use this value as start offset. So any u-boot's partition table parser +and file system command work consistently. You can access this area by using +mflash command. + +Following example sets 10MB of reserved area. +#define CONFIG_MG_DISK_RES 10240 + +2-2. Porting mg_get_drv_data function +Mflash is active device and need some gpio control for proper operation. +This board dependency resolved by using mg_get_drv_data function. +Port this function at your board init file. See include/mg_disk.h + +Here is some pseudo example. + +static void custom_hdrst_pin (u8 level) +{ + if (level) + /* set hard reset pin to high */ + else + /* set hard reset pin to low */ +} + +static void custom_ctrl_pin_init (void) +{ + /* Set hard reset, write protect, deep power down pins + * to gpio. + * Set these pins to output high + */ +} + +struct mg_drv_data* mg_get_drv_data (void) +{ + static struct mg_drv_data prv; + + prv.base = /* base address of mflash */ + prv.mg_ctrl_pin_init = custom_ctrl_pin_init; + prv.mg_hdrst_pin = custom_hdrst_pin; + + return &prv; +} + +3. Mflash command + +* initialize : mgd init +* random read : mgd read [from] [to] [size] + ex) read 256 bytes from 0x300000 of mflash to 0xA0100000 of host memory + mgd read 0x300000 0xA0100000 256 +* random write : mgd write [from] [to] [size] +* sector read : mgd readsec [sector] [to] [count] + ex) read 10 sectors starts from 400 sector to 0xA0100000 + mgd readsec 400 0xA0100000 10 +* sector write : mgd writesec [from] [sector] [count] + +4. Misc. +Mflash's device interface name for block driver is "mgd". +Here is ext2 file system access example. + + mgd init + ext2ls mgd 0:1 /boot + ext2load mgd 0:1 0xa0010000 /boot/uImage 1954156 |