2009-02-26 09:41:04     [BF527] GPIO Assisted Flash addressing

Document created by Aaronwu Employee on Aug 14, 2013
Version 1Show Document
  • View in full screen mode

2009-02-26 09:41:04     [BF527] GPIO Assisted Flash addressing

V Hemanth Kumar (INDIA)

Message: 70005   




We are designing a BF527 custom board and we have planned to use a 16MB flash (CFI compliant).


BF527 supports only 4MB of ASYNC bank. We are using 2 GPIO's (PH12 and PH11) for remaining 12 MB access.


I have referred the MTD documentation:-




and as mentioned in the document I also referred "arch/blackfin/mach-bf537/boards/cm_bf537.c" file


(in SVN trunk) for GPIO assisted flash addressing scheme.


So for our custom board are the below changes valid?:-




File: "arch/blackfin/mach-bf527/boards/custom_bf527.c"


static unsigned custom_flash_gpios[] = { GPIO_PH12, GPIO_PH11 };


static struct resource custom_flash_resource[] = {


                .name  = "cfi_probe",

                .start = 0x20000000,

                .end   = 0x203fffff,

                .flags = IORESOURCE_MEM,

        }, {

                .start = (unsigned long)custom_flash_gpios,

                .end   = ARRAY_SIZE(custom_flash_gpios),

                .flags = IORESOURCE_IRQ,




static struct platform_device custom_flash_device = {

        .name          = "gpio-addr-flash",

        .id            = 0,

        .dev = {

                .platform_data = &custom_flash_data,


        .num_resources = ARRAY_SIZE(custom_flash_resource),

        .resource      = custom_flash_resource,





1. Am I missing anything here or is there anything important steps which I have not considered?


2. With these changes and by including the "GPIO-assisted Flash Chip Support" option in


the distribution, will I be able to access all the 16MB of flash?


Please give your valuable suggestions.


Also I request, to provide me with few pointers on how to add/create folders and files in the uClinux distribution


for the new customized boards/platforms.


Thanks. Hemanth.





2009-02-26 10:55:17     Re: [BF527] GPIO Assisted Flash addressing

Mike Frysinger (UNITED STATES)

Message: 70012   


have you actually tried this or are you asking without testing ?


as for managing your board in the uClinux distribution, read the documentation:





2009-02-26 23:33:32     Re: [BF527] GPIO Assisted Flash addressing

V Hemanth Kumar (INDIA)

Message: 70059   


Hello Mike


We have not tested the code, the custom board is not yet physically available.


So we are preparing the code which can be tested later.