Problem writing to flash with writeb()

Problem writing to flash with writeb()

[Gettert, Wolfram]

Hallo,
I try to identify my flash with manufacturer id and device id.
Because I am using the 2.2.18 kernel and I want to be portable I
use the physmap_read/writeX() functions. They are defined as followed. 

void physmap_writeX(struct map_info *map, __u8 d, unsigned long adr)
{
	__raw_writeX(d, map->map_priv_1 + adr);
	mb();
}

In the 2.2.18 __rawreadb is not defined so I have done this.

#define __raw_readX readX
#define __raw_writeX writeX


Now I want to identify the flash doing this

	volatile char *p;
	u32 manufacturer, device;
	
  	physmap_map.map_priv_1 = (unsigned long)ioremap_nocache(WINDOW_ADDR,
WINDOW_SIZE);

	...
	
	//Read Manufacturer and Device code	
	physmap_write8(&physmap_map,0x90,physmap_map.map_priv_1);
	manufacturer = physmap_read8(&physmap_map,0);
	device = physmap_read8(&physmap_map,2);	
	printk("Manufacturer Code: 0x%x\n",manufacturer);
	printk("Device Code: 0x%x\n",device);

The result in log is:

Manufacturer Code: 0xff
Device Code: 0xff

If I do it like this:

	p = physmap_map.map_priv_1;
	p[0] = 0x90;
	printk("Manufacturer Code: 0x%x\n",p[0]);
	printk("Device Code: 0x%x\n",p[2]);
	
The result in log is:

Manufacturer Code: 0xffffff98
Device Code: 0xffffff9c

That's what I expect. *p needs to declared as volatile to let this work.
But I want to use readb ... Any ideas?

Thanks

Wolfram

--
Wolfram Gettert
Software Engineer 
Force Computers GmbH
- A Solectron Company -
Lilienthalstr. 15 
D-85579 Neubiberg/München
Wolfram.Gettert_at_fci.com
www.forcecomputers.com

Re: Problem writing to flash with writeb()

[J B]

>   	physmap_map.map_priv_1 = (unsigned 
>long)ioremap_nocache(WINDOW_ADDR,WINDOW_SIZE);
>
>	...
>
>	//Read Manufacturer and Device code
>	physmap_write8(&physmap_map,0x90,physmap_map.map_priv_1);

Are you sure you want to pass physmap_map.map_priv_1 as the address?  That 
would imply that the address you are writing 0x90 to is (2 * 
physmap_map.map_priv_1) because physmap_writeX will add map->map_priv_1 to 
whatever address you pass it.  If that is bigger than WINDOW_SIZE, I don't 
think the command will actually reach the flash chip because the address 
isn't mapped to a flash chip.  I am assuming you are using a cfi compliant 
flash chip and 0x90 is putting it into "Read Identifier Codes".  Try using 0 
for the address instead, which is what you did below.

>If I do it like this:
>
>	p = physmap_map.map_priv_1;
>	p[0] = 0x90;

Looks like this is the equivalent of:
physmap_write8(&physmap_map,0x90,0);


I could be very wrong however.  I still consider myself a newbie, so sorry 
if this doesn't make any sense.  Hope it helps though.


Josh

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Re: Problem writing to flash with writeb()

[David Woodhouse]

mad_flasher@hotmail.com said:
>  Looks like this is the equivalent of: physmap_write8(&physmap_map,0x90
> ,0); 

It does. Show disassembly of each version.

--
dwmw2

RE: Problem writing to flash with writeb()

[Gettert, Wolfram]

Thanks for the hint.

I was really blind.

Wolfram

> -----Original Message-----
> From: J B [mailto:mad_flasher@hotmail.com]
> Sent: Dienstag, 12. November 2002 20:02
> To: Wolfram.Gettert@fci.com; linux-mtd@lists.infradead.org
> Subject: Re: Problem writing to flash with writeb()
> 
> 
> 
> >   	physmap_map.map_priv_1 = (unsigned 
> >long)ioremap_nocache(WINDOW_ADDR,WINDOW_SIZE);
> >
> >	...
> >
> >	//Read Manufacturer and Device code
> >	physmap_write8(&physmap_map,0x90,physmap_map.map_priv_1);
> 
> Are you sure you want to pass physmap_map.map_priv_1 as the 
> address?  That 
> would imply that the address you are writing 0x90 to is (2 * 
> physmap_map.map_priv_1) because physmap_writeX will add 
> map->map_priv_1 to 
> whatever address you pass it.  If that is bigger than 
> WINDOW_SIZE, I don't 
> think the command will actually reach the flash chip because 
> the address 
> isn't mapped to a flash chip.  I am assuming you are using a 
> cfi compliant 
> flash chip and 0x90 is putting it into "Read Identifier 
> Codes".  Try using 0 
> for the address instead, which is what you did below.
> 
> >If I do it like this:
> >
> >	p = physmap_map.map_priv_1;
> >	p[0] = 0x90;
> 
> Looks like this is the equivalent of:
> physmap_write8(&physmap_map,0x90,0);
> 
> 
> I could be very wrong however.  I still consider myself a 
> newbie, so sorry 
> if this doesn't make any sense.  Hope it helps though.
> 
> 
> Josh
> 
> _________________________________________________________________
> The new MSN 8: smart spam protection and 2 months FREE*  
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