Common Flash Driver HOWTO

This module can provide common flash read/write API for different flash chips 
in user/kernel mode and  we only need to modify header file to support new flash chip.

1. How to enable common flash driver

#make menuconfig
Customize Kernel Settings->Ralink Common Flash Driver->

 [*]     	Ralink Common Flash R/W API (NEW)                                  
 (BC400000)     Physical start address of flash mapping                     
 [*]     	Mxic MX29LV320                                                     
 [*]     	EON  EN29LV320    


Notes: Flash driver module is located at /RT288x_SDK/source/linux-2.4.x/drivers/flash


2. How to support new flash chips.

We only need to modify the flash_tbl.h to support new flash chip.

For example:

 { .man_id= 0xc2, /* Mxic */
   .dev_id= 0x22A7, /* MX29LV320T */
   .max_sector = 70,
   .sector= {
             {.size=KBYTES(64),.count=63},
             {.size=KBYTES(8),.count=8}
            }
 },


The above definition means....
 .Manufacturer id = 0xC2
 .Device id=0x22A7
 .Max sector ID =70
 .63 sectors in front of the flash are 64Kbytes, and 8 sectors at the back are 8Kbytes


3. Using Flash API in kernel mode

Kernel modules call the following API to read/write/erase flash.

FlashRead(dst,src,count);
FlashWrite(src, dst , count); 
FlashErase(firstSector, lastSector);

Example:

FlashWrite(buf, 0x35FFF8, sizeof(buf));  /* write buf to Address 0xBC75FFF8 */
FlashRead( buf, 0x35FFF8 10); /* read 10 bytes from 0xBC75FFF8 to buf */
FlashErase(60,61);  /* erase sector 60~ sector 61*/

4. Using Flash API in user mode

The same as coding in kernel mode. User program call FlashRead/FlashWrite/FlashErase
function to read/write/erase flash. 
(reference RT288x_SDK/source/user/rt2880_app/flash/flash_api.c in detail)


5. How to verify the common flash driver 

#make menuconfig
Customize Vendor/User Settings->Ralink RT288x Application->

[*] RT288x Application   
[*] RT2880 ATE Agent                                        
[*] RT2880 Register R/W                                     
[*] RT2880 CLI                                              
[*] RT2880 CSR Test                                         
[*] RT2880 Flash Test   

Test program named flash will be generated at /bin

Command Format:
flash -r [offset(hex)] -c [num of bytes]
flash -w [offset(hex)] -o [value(hex)] -c [num of bytes]
flash -f [first sector_num] -l [last sector_num]

Example:
# flash -r 370000 -c 4    
370000: FFFFFFFF
370001: FFFFFFFF
370002: FFFFFFFF
370003: FFFFFFFF

# flash -w 370000 -o 1234 -c 4
Write 4 bytes data to 370000

# flash -r 370000 -c 4
370000: 31
370001: 32
370002: 33
370003: 34

/ # flash -f 62 -l 62
Erase Sector Number from 62 to 62

/ # flash -r 370000 -c 4
370000: FFFFFFFF
370001: FFFFFFFF
370002: FFFFFFFF
370003: FFFFFFFF
