MPC 8349e-mITX and MTD/Flash

MPC 8349e-mITX and MTD/Flash

[Benedict, Michael]

Hello,
	Quite simply, I am trying to access the attached flash devices
for this platform from linux.  I tried to select all the appropriate MTD
settings that I thought could apply.  However, nothing shows up in
/proc/mtd.  Can someone point me in the right direction for accessing
these?  =09

>From the documentation: "The two Flash memory banks are MX29LV640MTTC-90
top boot Flash memory devices"

	Thank you!
		Michael

RE: MPC 8349e-mITX and MTD/Flash

[Benedict, Michael]

Ben,
	I assume that you intended to CC the list but accidently hit
"reply" instead.  If not, I apologize.  Thank you for all your help so
far.

>-----Original Message-----
>From: Ben Warren [mailto:bwarren@qstreams.com]=20
>Sent: Monday, April 09, 2007 4:30 PM
>To: Benedict, Michael
>Subject: Re: MPC 8349e-mITX and MTD/Flash
>
>I suspect that MTD doesn't know anything about how
>your flash chip is organized.  Probably the easiest
>thing to use is CONFIG_MTD_PHYSMAP.  Using this, you
>can either pass the MTD partitioning info via kernel
>command line, via static physmap structures in your
>board code or, I believe, via device tree (I haven't
>tried the last one).

The following is from my .config
<snip>
#
# Mapping drivers for chip access
#
# CONFIG_MTD_COMPLEX_MAPPINGS is not set
CONFIG_MTD_PHYSMAP=3Dy
CONFIG_MTD_PHYSMAP_START=3D0x8000000
CONFIG_MTD_PHYSMAP_LEN=3D0x0
CONFIG_MTD_PHYSMAP_BANKWIDTH=3D2
# CONFIG_MTD_PHYSMAP_OF is not set
CONFIG_MTD_PLATRAM=3Dy
<snip>

Is this what you are referring to?  Does something look obviously wrong
with it?  I have taken that configuration from Freescale's reference
.config that came with the platform.  I am using the latest kernel.org
flat device tree for my platform, but the flash is not configured there.

After reading a little more, I suppose I am not expecting any
partitions, but I would still think I should be able to `mtd_debug info`
the block and char devices.  When I try, I get "No such device or
address" errors.  Also, I would still expect something in my /proc/mtd,
correct?  Any ideas are greatly appreciated.
	Thank you again,
		Michael

Re: MPC 8349e-mITX and MTD/Flash

[Sergei Shtylyov]

Hello.

Benedict, Michael wrote:
> Ben,
> 	I assume that you intended to CC the list but accidently hit
> "reply" instead.  If not, I apologize.  Thank you for all your help so
> far.

>>-----Original Message-----
>>From: Ben Warren [mailto:bwarren@qstreams.com] 
>>Sent: Monday, April 09, 2007 4:30 PM
>>To: Benedict, Michael
>>Subject: Re: MPC 8349e-mITX and MTD/Flash

>>I suspect that MTD doesn't know anything about how
>>your flash chip is organized.  Probably the easiest
>>thing to use is CONFIG_MTD_PHYSMAP.  Using this, you
>>can either pass the MTD partitioning info via kernel
>>command line, via static physmap structures in your
>>board code or, I believe, via device tree (I haven't
>>tried the last one).

> The following is from my .config
> <snip>
> #
> # Mapping drivers for chip access
> #
> # CONFIG_MTD_COMPLEX_MAPPINGS is not set
> CONFIG_MTD_PHYSMAP=y
> CONFIG_MTD_PHYSMAP_START=0x8000000
> CONFIG_MTD_PHYSMAP_LEN=0x0
> CONFIG_MTD_PHYSMAP_BANKWIDTH=2
> # CONFIG_MTD_PHYSMAP_OF is not set
> CONFIG_MTD_PLATRAM=y
> <snip>
> 
> Is this what you are referring to?  Does something look obviously wrong
> with it?

    Yeah, CONFIG_MTD_PHYSMAP_LEN shoudn't be 0 unless you're registering your 
MTD via the platform device mechanism (and in that case specifying 
CONFIG_MTD_PHYSMAP_START and CONFIG_MTD_PHYSMAP_BANKWIDTH doesn't make sense).

WBR, Sergei

RE: MPC 8349e-mITX and MTD/Flash

[Ben Warren]

On Tue, 2007-04-10 at 09:06 -0500, Benedict, Michael wrote:
> Ben,
> 	I assume that you intended to CC the list but accidently hit
> "reply" instead.  If not, I apologize.  Thank you for all your help so
> far.
> 
You guessed right.  Sorry about that.  Thanks for bringing it back in!
> >-----Original Message-----
> >From: Ben Warren [mailto:bwarren@qstreams.com] 
> >Sent: Monday, April 09, 2007 4:30 PM
> >To: Benedict, Michael
> >Subject: Re: MPC 8349e-mITX and MTD/Flash
> >
> >I suspect that MTD doesn't know anything about how
> >your flash chip is organized.  Probably the easiest
> >thing to use is CONFIG_MTD_PHYSMAP.  Using this, you
> >can either pass the MTD partitioning info via kernel
> >command line, via static physmap structures in your
> >board code or, I believe, via device tree (I haven't
> >tried the last one).
> 
> The following is from my .config
> <snip>
> #
> # Mapping drivers for chip access
> #
> # CONFIG_MTD_COMPLEX_MAPPINGS is not set
> CONFIG_MTD_PHYSMAP=y
> CONFIG_MTD_PHYSMAP_START=0x8000000
> CONFIG_MTD_PHYSMAP_LEN=0x0
> CONFIG_MTD_PHYSMAP_BANKWIDTH=2
> # CONFIG_MTD_PHYSMAP_OF is not set
> CONFIG_MTD_PLATRAM=y
> <snip>
> 
> Is this what you are referring to?  Does something look obviously wrong
> with it?  I have taken that configuration from Freescale's reference
> .config that came with the platform.  I am using the latest kernel.org
> flat device tree for my platform, but the flash is not configured there.
> 
This is mostly right, but it only defines the physical mapping of the
NOR device, not how it is partitioned.  The PHYSMAP_LEN shouldn't be
zero, though.  In my case, I have:

CONFIG_MTD_PHYSMAP=y
CONFIG_MTD_PHYSMAP_START=0xfe000000
CONFIG_MTD_PHYSMAP_LEN=0x800000
CONFIG_MTD_PHYSMAP_BANKWIDTH=2

This indicates that the flash chip is mapped to address 0xfe000000, is
0x800000 bytes (8MB) and is two bytes wide (16 bits).

> After reading a little more, I suppose I am not expecting any
> partitions, but I would still think I should be able to `mtd_debug info`
> the block and char devices.  When I try, I get "No such device or
> address" errors.  Also, I would still expect something in my /proc/mtd,
> correct?  Any ideas are greatly appreciated.

I don't know for sure, but setting the LEN field properly might make it
show up in /proc/mtd.  

Here's some simple code you might find useful as a starting point for
statically defining the partitions in your board code.  It will allow
you to access /dev/mtdx and /dev/mtdblockx.  I don't know if this is the
'right' way, but it works:

#ifdef CONFIG_MTD_PHYSMAP

static int __init board_setup_mtd(void)
{
	int	ptbl_entries;
	static struct mtd_partition	*ptbl;

	ptbl_entries = 2;

	if ((ptbl = kcalloc(ptbl_entries, sizeof(struct mtd_partition),
			GFP_KERNEL)) == NULL) {
		printk(KERN_WARNING "Can't alloc MTD partition table\n");
		return -ENOMEM;
	}

	ptbl[0].name = "part-1";
	ptbl[0].size = 0x40000;		/* 256 k */
	ptbl[1].name = "part-2";
	ptbl[1].offset = 0x40000;
	ptbl[1].size = 0x7c0000; 	/* rest of 8MB */

	physmap_set_partitions(ptbl, ptbl_entries);
	return 0;
}
arch_initcall(board_setup_mtd);
#endif

Re: MPC 8349e-mITX and MTD/Flash

[Timur Tabi]

Benedict, Michael wrote:

> # CONFIG_MTD_COMPLEX_MAPPINGS is not set
> CONFIG_MTD_PHYSMAP=y
> CONFIG_MTD_PHYSMAP_START=0x8000000
> CONFIG_MTD_PHYSMAP_LEN=0x0
> CONFIG_MTD_PHYSMAP_BANKWIDTH=2
> # CONFIG_MTD_PHYSMAP_OF is not set
> CONFIG_MTD_PLATRAM=y

This what the latest defconfig for the 8349ITX has:

CONFIG_MTD=y
CONFIG_MTD_CHAR=y
CONFIG_MTD_CFI=y
CONFIG_MTD_GEN_PROBE=y
CONFIG_MTD_MAP_BANK_WIDTH_1=y
CONFIG_MTD_MAP_BANK_WIDTH_2=y
CONFIG_MTD_MAP_BANK_WIDTH_4=y
CONFIG_MTD_CFI_I1=y
CONFIG_MTD_CFI_I2=y
CONFIG_MTD_CFI_AMDSTD=y
CONFIG_MTD_CFI_UTIL=y
CONFIG_MTD_PHYSMAP=y
CONFIG_MTD_PHYSMAP_START=0xfe000000
CONFIG_MTD_PHYSMAP_LEN=0x1000000
CONFIG_MTD_PHYSMAP_BANKWIDTH=2

Your settings for CONFIG_MTD_PHYSMAP_START and CONFIG_MTD_PHYSMAP_LEN are wrong.  And 
frankly, I can't understand where you got those values from, unless you created your 
.config from scratch.  The defconfig that's in the kernel is specifically intended for the 
Freescale MPC8349E-mITX.  I should know, because I wrote the code and the defconfig.

Having said that, it seems that the kernel now supports defining the physmap via the OF 
tree.  Is that true?

-- 
Timur Tabi
Linux Kernel Developer @ Freescale

RE: MPC 8349e-mITX and MTD/Flash

[Benedict, Michael]

>Your settings for CONFIG_MTD_PHYSMAP_START and=20
>CONFIG_MTD_PHYSMAP_LEN are wrong.  And=20
>frankly, I can't understand where you got those values from,=20
>unless you created your=20
>.config from scratch.  The defconfig that's in the kernel is=20
>specifically intended for the=20
>Freescale MPC8349E-mITX.  I should know, because I wrote the=20
>code and the defconfig.

I didn't even know about the defconfig until I started looking into this
issue.  I tried to "upgrade" the .config that came with the CD but I
can't tell you how I introduced these values.  That said, I was able to
change my configuration to the values in the defconfig and...

# mtd_debug info /dev/mtd0
mtd.type =3D MTD_NORFLASH
mtd.flags =3D
mtd.size =3D 16777216 (16M)
mtd.erasesize =3D 65536 (64K)
mtd.oobblock =3D 1
mtd.oobsize =3D 0
mtd.ecctype =3D MTD_ECC_NONE
regions =3D 4

region[0].offset =3D 0x00000000
region[0].erasesize =3D 65536 (64K)
region[0].numblocks =3D 127
region[0].regionindex =3D 0
region[1].offset =3D 0x007f0000
region[1].erasesize =3D 8192 (8K)
region[1].numblocks =3D 8
region[1].regionindex =3D 1
region[2].offset =3D 0x00800000
region[2].erasesize =3D 65536 (64K)
region[2].numblocks =3D 127
region[2].regionindex =3D 2
region[3].offset =3D 0x00ff0000
region[3].erasesize =3D 8192 (8K)
region[3].numblocks =3D 8
region[3].regionindex =3D 3

Its working!  Thank you everyone for helping me figure this out.

>
>Having said that, it seems that the kernel now supports=20
>defining the physmap via the OF=20
>tree.  Is that true?


Initially I was going to try and define this via the OF tree.  However,
the documentation indicated that the only supported device_type was
"rom" so I did not persue that route.
	-Michael

Re: MPC 8349e-mITX and MTD/Flash

[Vitaly Bordug]

On Tue, 10 Apr 2007 10:48:43 -0500
Timur Tabi <timur@freescale.com> wrote:

> Having said that, it seems that the kernel now supports defining the physmap via the OF 
> tree.  Is that true?

Yes, we drafted some stuff while working on mpc8540ads - see
drivers/mtd/maps/physmap_of.c

-- 
Sincerely, 
Vitaly

Re: MPC 8349e-mITX and MTD/Flash

[Sergei Shtylyov]

Hello.

Benedict, Michael wrote:

>>Having said that, it seems that the kernel now supports 
>>defining the physmap via the OF 
>>tree.  Is that true?

> Initially I was going to try and define this via the OF tree.  However,
> the documentation indicated that the only supported device_type was
> "rom" so I did not persue that route.

   There was long discussion about using "mtd" and other types -- people were 
complaining that "mtd" was too Linux-centric term, so finally we ended up with 
"rom".  It doesn't imply that ROMs are the only supported devices. :-)

WBR, Sergei

Re: MPC 8349e-mITX and MTD/Flash

[Timur Tabi]

Sergei Shtylyov wrote:
> Hello.
> 
> Benedict, Michael wrote:
> 
>>> Having said that, it seems that the kernel now supports defining the 
>>> physmap via the OF tree.  Is that true?
> 
>> Initially I was going to try and define this via the OF tree.  However,
>> the documentation indicated that the only supported device_type was
>> "rom" so I did not persue that route.
> 
>   There was long discussion about using "mtd" and other types -- people 
> were complaining that "mtd" was too Linux-centric term, so finally we 
> ended up with "rom".  It doesn't imply that ROMs are the only supported 
> devices. :-)

Okee dokee.  I'll add it to my to-do list.

-- 
Timur Tabi
Linux Kernel Developer @ Freescale