On Friday, February 11, 2011 11:51:24 pm Albert ARIBAUD wrote:
Le 12/02/2011 08:14, Aaron Williams a écrit :
On Friday, February 11, 2011 11:01:40 pm Albert ARIBAUD wrote:
Le 12/02/2011 07:42, Aaron Williams a écrit :
I've placed the results of the scan below.
The problem is that in 8-bit mode the code that scans the CFI does not follow the specification.
In the specification to read the CFI data you write 0x98 to address 0xAA, not address 0x55 as you do in 16-bit mode. flash_offset_cfi is set to 0x55 which in this case is wrong and won't work. When it tries 16-bit mode then it writes to address 0xAA which causes it to work.
Let us see the specs, then. The specs I have (admittedly not necessarily the latest: I use JESD 68.01, september 1999) state the following:
"Nonvolatile memory devices are assumed to power up in a read-only state. Independent of that assumption, the Query structure contents must be able to be read at the specific address locations following a single system write cycle where: 1) a 98h Query command code is written to 55h address location within the device’s address space (in maximum device buswidth), and 2) the device is in any valid read state, such as “Read Array” or “Read ID Data”.
I read "55h address location within the device’s address space (in maximum device buswidth" as implying that 0x55 is the only address to use but is in device bus terms, and that may mean different CPU addresses for different devices types: for x8 devices, one should access the byte address 0x55 because the device bus is in bytes, whereas for x8/x16 and x16 devices, one should access byte address 0xAA because it translates to x16 device bus address 0x55 -- regardless of actual x8 or x16 mode.
Are we in sync here?
This is wrong. The address is actually 0xAA in x8 mode and 0x55 in x16 mode according to the data sheet.
Yes, but the 0xAA address is a byte address and the 0x55 address is a word address, translating to byte address 0xAA as well.
On the JESD 68.01 spec, page number 3 (that's PDF page 9), the byte location for a pure x8 device is 0x55, and 0xAA for a x16 device, both in x16 or x8 mode (the difference is that byte mode will expect a byte write of 0x98 where x16 mode will expect a word write of 0x0098).
This is in sync with my Macronix MX29LV400CB/CT spec.
Now it's been a long time since I last looked at my ED Mini V2 Flash, but I should be able to dig it up and do a test within one or two hours.
-Aaron
Here's the results of the scan:
Yes, that's what U-boot *CFI code* does, but I'd like to see what very basic writes and reads give without any detection logic involved.
Amicalement,
When I use the addresses and data shown in the datasheet, everything responds as it should using mw.b and md.b.
Octeon ebb6300(ram)# mw.b 0x1f400000 0xf0 Octeon ebb6300(ram)# mw.b 0x1f400aaa 0xaa Octeon ebb6300(ram)# mw.b 0x1f400555 0x55 Octeon ebb6300(ram)# mw.b 0x1f400aaa 0x90 Octeon ebb6300(ram)# md.b 0x1f400000 1 1f400000: 01 . Octeon ebb6300(ram)# md.b 0x1f400002 1 1f400002: 7e ~ Octeon ebb6300(ram)# md.b 0x1f400004 1 1f400004: 00 .
Octeon ebb6300(ram)# mw.b 0x1f400000 0xf0 Octeon ebb6300(ram)# mw.b 0x1f4000AA 0x98 Octeon ebb6300(ram)# md.b 0x1f400020 1f400020: 51 Q Octeon ebb6300(ram)# md.b 0x1f400022 1f400022: 52 R Octeon ebb6300(ram)# md.b 0x1f400024 1f400024: 59 Y Octeon ebb6300(ram)# md.b 0x1f400026 1f400026: 02 . Octeon ebb6300(ram)# md.b 0x1f400028 1f400028: 00 .
-Aaron
The CFI query is normal for a x16 device: byte address 0xAA is word address 0x55, which is what is expected from a x16 device in x8 mode as in x16 mode.
Can you try a 'md.b 0x1f400020 20' once in CFI QRY mode?
Amicalement,
You mean like this?
Octeon ebb6300(ram)# mw.b 0x1f400000 0xf0 Octeon ebb6300(ram)# mw.b 0x1f400aaa 0xaa Octeon ebb6300(ram)# mw.b 0x1f400555 0x55 Octeon ebb6300(ram)# mw.b 0x1f400aaa 0x90 Octeon ebb6300(ram)# md.b 0x1f400000 0 Octeon ebb6300(ram)# md.b 0x1f400000 1 1f400000: 01 . Octeon ebb6300(ram)# md.b 0x1f400002 1 1f400002: 7e ~ Octeon ebb6300(ram)# md.b 0x1f400004 1 1f400004: 00 . Octeon ebb6300(ram)# md.b 0x1f400005 1 1f400005: 00 . Octeon ebb6300(ram)# md.b 0x1f400006 1 1f400006: 1a . Octeon ebb6300(ram)# md.b 0x1f400008 1 1f400008: 00 . Octeon ebb6300(ram)# md.b 0x1f40000a 1 1f40000a: 00 . Octeon ebb6300(ram)# mw.b 0x1f400000 0xf0 Octeon ebb6300(ram)# mw.b 0x1f4000AA 0x98 Octeon ebb6300(ram)# md.b 0x1f400020 1f400020: 51 Q Octeon ebb6300(ram)# md.b 0x1f400022 1f400022: 52 R Octeon ebb6300(ram)# md.b 0x1f400024 1f400024: 59 Y Octeon ebb6300(ram)# md.b 0x1f400026 1f400026: 02 . Octeon ebb6300(ram)# md.b 0x1f400028 1f400028: 00 .
-Aaron