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Date: Wed, 10 Jan 2001 14:15:16 -0500
From: =?iso-8859-1?Q?St=E9phane?= Laroche <stephane.laroche@colubris.com>
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To: mtd@infradead.org
Subject: CFI problems with 32bit bus and 4 devices
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Hi,

I've just updated to the latest CVS and my CFI AMD chips are not
accessible anymore.

I lokked briefly into it and saw that the cfi->interleave and
cfi->device_type were removed from offset calculations when accessing
the devices.

So, for my setup, which has 4 x16 devices on a 32 bit bus (AMDs),  the
CFI query structure is located at offsets 0x80, 0x88, 0x90, etc.

cfi_read_query()  uses only the buswidth to calculate the offset, which
is not general enough (it used to be like that before I played with the
code a bit last summer).  It's obviously wrong in my case ( 0x10 << 2 !=
0x80 ).

Rewriting cfi_read_query like this made the CFI query structure
readable:

static inline __u8 cfi_read_query(struct map_info *map, __u32 base,
__u32 addr)
{
    struct cfi_private *cfi = map->fldrv_priv;
    addr *= cfi->interleave * cfi->device_type;  /* instead of addr <<
(buswidth / 2) */
    if (cfi_buswidth_is_1()) {
        return map->read8(map, base + addr);
    } else if (cfi_buswidth_is_2()) {
        return cfi16_to_cpu(map->read16(map, base + addr));
    } else if (cfi_buswidth_is_4()) {
        return cfi32_to_cpu(map->read32(map, base + addr));
    } else {
        return 0;
    }
}

With this change, the chips are now properly recognized.  But I can't
still not use them (reads are wrong), so I think I have to look at
cfi_cmdset_002.c to bring back the use of cfi->interleave in some
calculations...

Any comments?  Is it possible that I'm the only one using that kind of
geometry?

-Stephane



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