Re: [ECOS] simple Atmel AT91EB40 Flash driver question

[Gary Thomas <gthomas at redhat dot com>]

On Fri, 2002-04-12 at 12:18, Pete Barrie wrote:
> The AT91EB40 port uses the flash drivers in
> devs/flash/arm/at91 (as far as I can see) and includes
> the following code in at91_flash.c:
> 
>      if (data[1] == (unsigned short)FLASH_ATMEL_29LV1024) {
>          num_regions = 256;    //sector
>          region_size = 0x100;  // words in
> 
> However, this device actually has 512 sectors with 128 words(16-bit)
> per sector
>
 
> Q1. Is num_regions = 256 because only the top half
> of the flash is being made accessible for programming?
> Total flash is 0x01000000 to 0x0101FFFF
> eCos allows use of 0x01010000 onwards

Indeed.  To be safe (and not turn these cute little boards into bricks),
ecos only uses the upper half of the device, leaving the lower half for
the extant monitor.

> 
> Q2. Is region_size = 0x100 because this is expressed in bytes
> rather than words? I take it the region_size means the same as sector size.
> 

Region size is measured in bytes - 128 words = 256 bytes.

> Current init code is below below.
> 
> Thanks
> Pete
> 
> 
> int
> flash_hwr_init(void)
> {
>      unsigned short data[4];
>      extern char flash_query, flash_query_end;
>      typedef int code_fun(unsigned char *);
>      code_fun *_flash_query;
>      int code_len, stat, num_regions, region_size;
> 
>      // Copy 'program' code to RAM for execution
>      code_len = (unsigned long)&flash_query_end - (unsigned long)&flash_query;
>      _flash_query = (code_fun *)flash_info.work_space;
>      memcpy(_flash_query, &flash_query, code_len);
>      HAL_DCACHE_SYNC();  // Should guarantee this code will run
> 
>      stat = (*_flash_query)(data);
> #if 0
>      (*flash_info.pf)("stat = %x\n", stat);
>      dump_buf(data, sizeof(data));
> #endif
> 
>      if (data[0] != FLASH_Atmel_code) {
>          (*flash_info.pf)("Not Atmel = %x\n", data[0]);
>          return FLASH_ERR_HWR;
>      }
> 
>      if (data[1] == (unsigned short)FLASH_ATMEL_29LV1024) {
>          num_regions = 256;
>          region_size = 0x100;
>      } else {
>          (*flash_info.pf)("Unknown device type: %x\n", data[1]);
>          return FLASH_ERR_HWR;
>      }
> 
>      // Hard wired for now
>      flash_info.block_size = region_size;
>      flash_info.blocks = num_regions;
>      flash_info.start = (void *)0x01010000;
>      flash_info.end = (void *)(0x01010000+(num_regions*region_size));
>      return FLASH_ERR_OK;
> }
> 
> 
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> and search the list archive: http://sources.redhat.com/ml/ecos-discuss



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