Hello,
The issue is that cpm_muram_alloc_fixed() allocates memory from the
general purpose muram area (from 0x0 to 0x1bff).
Here we need to return a pointer to the parameter RAM, which is located
somewhere starting at 0x1c00. It is not a dynamic allocation that is
required here but only to point on the correct location in the parameter
RAM.
For the CPM2, I don't know. I'm working with a MPC866.
Attached is a previous discussion on the subject where I explain a bit
more in details the issue.
Regards
C. Leroy
Le 24/09/2010 09:10, Grant Likely a écrit :
On Thu, Sep 16, 2010 at 09:05:03AM +0200, christophe leroy wrote:
This patch applies to 2.6.34.7 and 2.6.35.4
It fixes an issue during the probe for CPM1 with definition of parameter ram
from DTS
Signed-off-by: christophe leroy<christophe.le...@c-s.fr>
I'm sorry, I don't understand the fix from the given description.
What is the problem, and why is cpm_muram_alloc_fixed() the wrong
thing to call on CPM1? Does CPM2 still need it?
g.
diff -urN b/drivers/spi/spi_mpc8xxx.c c/drivers/spi/spi_mpc8xxx.c
--- b/drivers/spi/spi_mpc8xxx.c 2010-09-08 16:43:50.000000000 +0200
+++ c/drivers/spi/spi_mpc8xxx.c 2010-09-08 16:44:03.000000000 +0200
@@ -822,7 +822,7 @@
if (!iprop || size != sizeof(*iprop) * 4)
return -ENOMEM;
- spi_base_ofs = cpm_muram_alloc_fixed(iprop[2], 2);
+ spi_base_ofs = iprop[2];
if (IS_ERR_VALUE(spi_base_ofs))
return -ENOMEM;
@@ -844,7 +844,6 @@
return spi_base_ofs;
}
- cpm_muram_free(spi_base_ofs);
return pram_ofs;
}
--- Begin Message ---
On Tue, 7 Sep 2010 11:17:17 +0200
LEROY Christophe <christophe.le...@c-s.fr> wrote:
>
> Dear Kumar,
>
> I have a small issue in the init of spi_mpc8xxx.c with MPC866 (CPM1)
>
> Unlike cpm_uart that maps the parameter ram directly using
> of_iomap(np,1), spi_mpc8xxx.c uses cpm_muram_alloc_fixed().
>
> This has two impacts in the .dts file:
> * The driver must be declared with pram at 1d80 instead of 3d80 whereas
> it is not a child of mu...@2000 but a child of c...@9c0
> * mu...@2000/d...@0 must be declared with reg = <0x0 0x2000> whereas
> is should be reg=<0x0 0x1c00> to avoid cpm_muram_alloc() to allocate
> space from parameters ram.
>
> Maybe I misunderstood something ?
Don't make the device tree lie, fix the driver instead.
The allocator should not be given any chunks of muram that are
dedicated to a fixed purpose -- it might hand it out to something else
before you reserve it. I don't think that cpm_muram_alloc_fixed() has
any legitimate use at all.
-Scott
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