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