Re: [ECOS] Red-Boot & Multiple Flash IC's

[Jürgen Lambrecht <J dot Lambrecht at televic dot com>]

sebastian igielski wrote:
> Hi!
>
> We have porting Red-Boot to our platform based on EP9302 
> microprocessor (produced by Cirrus Logic, ARM920T core inside). I have 
> one question about using multiple flash IC's connected to different 
> chip selects, uut at first I must tell something about our hardware 
> platform.
>
> In a few words, we have on board following IC's:
>
> 1x MCU: EP9302 (ARM920T core, 16 bit wide data bus)
> 4x SDRAM (one SDRAM chip have 32Mbyte capacity, four banks - [8MBytes 
> per bank]) - Total: 128Mbytes of RAM
> 2x NOR FLASH (JS28F1283D) (connected to two separate chip selects) 
> (The NOR flash chips is Intel-Strata FLASH IC's.)
>
> One NOR-FLASH chip have 16-bit data bus. The NOR-Flash chips is placed 
> at 0x6000_0000 and 0x7000_0000 in physical memory layout. After 
> configuring and enabling the MMU the NOR-Flash chips is mapped as 
> follows (virtual address space):
>
> IC #1: 0x6000_0000 - 0x60FF_FFFF
> IC #2: 0x6100_0000 - 0x61FF_FFFF
>
> And now is my question about Red-Boot environment. It is possible to 
> (and how to do it) use both NOR flash chips?
> Now I have working only one chip (placed at virtual address: 
> 0x6000_0000-0x60FF_FFFF).
>
> I have no idea how to tell Red-Boot/Strata Flash driver to see my 
> second NOR-Flash chip. It is possible to RedBoot handle this kind of 
> hardware configuration?
>
> Some people told me that I must modify the "CYGNUM_FLASH_DEVICES", but 
> in my humble opinion this variable defines the FLASH IC's needed to 
> coverage the data bus by multiple FLASH IC's (for example: when I have 
> 32 bit wide data bus, and when I have two 16 bit FLASH IC's to 
> coverage 32-bit data bus - in that case CYGNUM_FLASH_DEVICES must be 
> set to 2). I'm correct?
i also think so
> In our hardware the data bus is 16-bit wide and FLASH IC is 16 bit 
> wide (so one flash chip coverage all data bus), the second FLASH IC is 
> used to extend size of flash memory size. As i written above, I have 
> working first FLASH CHIP. And I don't know to add second chip to 
> RedBoot environment.
>
> If anybody can suggest me right solution of my problem, or give any 
> helpful idea I will be graceful.
>
> I have ecos-2.0 package.
you should take the latest version from cvs
> with regards
> Sebastian Igielski
I have 1 flash IC of 64 MB, by I can only access 16 MB per chip select, 
so I use 4 chip selects to acces my flash. This is transparant for 
redboot. Redboot only sees 1 chip. My arm7 has no MMU; the 4 address 
ranges nicely follow each other; you need to do a correct mapping of the 
address/data bus to your address range.

I think to have 2 separate flash chips and 2 times mounting, you need 
the flash_v2 drivers (flash_v2 label in /io/flash).

Success,
Jürgen


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