[Openocd-development] XScale IXP42x 16-bit CFI flash detection fails

[Leon W. <leo...@gm...>]

Hello,

I am using a IXP420 processor with a 16-bit 28F128J3D75 Intel CFI
Flash device, in 16-bit mode. The processor runs in big-endian mode. I
use a BDI2000 under Linux, but am now setting up OpenOCD under Cygwin,
for production purposes at first instance.

Using OpenOCD from source, under CygWin under Windows XP (32-bit
little-endian), with a Amontec JTAGkey I cannot get the CFI flash
detection to work. I have tried the trunk (rev 206), xscale (rev 118)
and xscale-ixp-be (rev 179) branches.

Relevant piece of my config:

---
jtag_device 7 0x01 0x7f 0x7e
#target
target xscale big reset_halt 0 ixp42x
xscale debug_handler 0 0xfe000800
xscale cache_clean_address 0 0xfffe0000
#flash
#flash bank <type> <base> <size> <chip-width> <bus-width> <target#>
#chip and bus-width in byte
flash bank cfi 0x50000000 0x01000000 2 2 0
---

I think OpenOCD does not cover all 8-bit / 16-bit cases correctly, for
CFI querying, as described in Intel's Application Note 646 (Google for
"Intel AP-646").

# enable write access to flash chip select
mww 0xc4000000 0xbfff3c42

flash probe 0

probing failed for flash bank '#0' at 0x50000000

The log shows:

Debug:   xscale.c:1965 xscale_write_memory(): address: 0xc4000000,
size: 0x00000004, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000aaa,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000554,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000aaa,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1895 xscale_read_memory(): address: 0x50000000,
size: 0x00000002, count: 0x00000001
Debug:   target.c:784 target_read_u16(): address: 0x50000000, value: 0x0018
Debug:   xscale.c:1895 xscale_read_memory(): address: 0x50000002,
size: 0x00000002, count: 0x00000001
Debug:   target.c:784 target_read_u16(): address: 0x50000002, value: 0x0089
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000000,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000000,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x500000aa,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1895 xscale_read_memory(): address: 0x50000020,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1895 xscale_read_memory(): address: 0x50000022,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1895 xscale_read_memory(): address: 0x50000024,
size: 0x00000002, count: 0x00000001
Debug:   cfi.c:1692 cfi_probe(): CFI qry returned: 0x52 0x51 0x01
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000000,
size: 0x00000002, count: 0x00000001
Debug:   xscale.c:1965 xscale_write_memory(): address: 0x50000000,
size: 0x00000002, count: 0x00000001


I tried to manually probe the device as follows:

# enable write access to flash chip select
mww 0xc4000000 0xbfff3c42

# query
mwh 0x500000aa 0x0098

# read QRY using half-words (half word = 16-bit)
mdh 0x50000020 4
0052 0051 0001 0059
R
Q
0x01
Y

The above definitely seems wrong.

# read QRY using words (32-bit = word)
mdw 0x50000020 4
0051 0052 0059 0001
Q
R
Y
0x01


The half-word reads are re-ordered, the word reads are correctly ordered.

Everything works fine under the BDI2000, as a reference:

Core#0>mmh 0x500000aa 0x9898
Core#0>mdh 0x50000020 4
50000020 : 0x0051      81  .Q
50000022 : 0x0052      82  .R
50000024 : 0x0059      89  .Y
50000026 : 0x0001       1  ..
Core#0>mmh 0x500000aa 0x9898
Core#0>md 0x50000020 4
50000020 : 0x00510052      5308498  .Q.R
50000024 : 0x00590001      5832705  .Y..
50000028 : 0x00000031           49  ...1
5000002c : 0x00000000            0  ....



First, what OpenOCD code base should I take for my setup, and what
might go wrong here?

When viewing the source code of target/xscale.c:xscale_write_memory()
I see a relevant part of the code commented out.

Please enlighten me :-)

Regards,
-- 
Leon