[U-Boot] CFI flash broken for 8-bit bus

[Aaron Williams <Aaron.Williams@caviumnetworks.com>]

I have it working on our 8-bit boards properly now, though I've only done some 
limited testing.

I basically put in the correct addresses into cfi_flash.h and updated various 
addresses for 8-bit support. The problem was that the CFI code was written 
using the 16-bit addresses which don't work for an 8-bit bus.

I added a mask which is used to calculate the correct address for 16 and 32-
bit busses. I have only been able to test with 8-bit and 16-bit Spansion 
devices though.

-Aaron

On Friday, March 18, 2011 12:12:22 AM Rogan Dawes wrote:
> On 2011/03/18 6:02 AM, Aaron Williams wrote:
> > Hi,
> > 
> > I am running into issues in that the CFI code is broken for flash with an
> > 8- bit bus. The problem is that the CFI code uses the wrong addresses
> > for 8-bits vs 16-bits.
> > 
> > The CFI function flash_map incorrectly calculates the byte offset with
> > Spansion flash.
> > 
> > In our case, we have an 8-bit Spansion S29GL-N MirrorBit flash chip on an
> > 8- bit bus.
> > 
> > According to the data sheet, in 8-bit mode the first unlock address is
> > 0xAAA and the second is 0x555. Basically all of the addresses are
> > approximately double what they are in 16-bit mode.
> > 
> > Most of the addresses in the CFI code are wrong for 8-bit mode.
> > 
> > They should be as follows:
> > unlock1: 0xAAA
> > unlock2: 0x555
> > CFI Query: 0xAA
> > 
> > Offset Device ID: 0x02, 0x1c, 0x1e
> > Offset Silicon Sector Factory Protect: 0x6
> > Sector protect verify (sector address) + 4
> > 
> > The problem is that the dectection code detects (incorrectly) that we're
> > an 8- bit device on a 16-bit bus when in fact it's an 8-bit bus.
> > 
> > For 16-bits, it's:
> > 
> > unlock1: 0x555
> > unlock2: 0x2aa
> > CFI Query: 0x55
> > Offset Device ID: 0x1, 0x0e, 0x0f
> > 
> > Now, in 16-bit mode these addresses should be effectively doubled so they
> > should look to be the same to software as I understand it.
> > 
> > This is all taken from the datasheet.
> > 
> > Note that the CFI code works fine with the flash hooked up as 16-bit on a
> > 16- bit bus.
> > 
> > If it's an 8-bit flash on a 16-bit bus then the addresses should be
> > doubled.
> > 
> > 
> > 
> > -Aaron
> 
> Hi Aaron,
> 
> Does this patch (originally by Stefan Roese) work for you? I also need
> it for the DNS323 port. FWIW, mine is also a Spansion flash
> (S29GL064M90TFIR4), although I am not 100% sure of the layout and
> connectivity.
> 
> Rogan
> 
> ---
>  drivers/mtd/cfi_flash.c |   22 +++++++++++++++++++++-
>  1 files changed, 21 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
> index dd394a8..74e9ade 100644
> --- a/drivers/mtd/cfi_flash.c
> +++ b/drivers/mtd/cfi_flash.c
> @@ -291,6 +291,9 @@ static inline uchar flash_read_uchar (flash_info_t *
> info, uint offset)
>  	uchar *cp;
>  	uchar retval;
> 
> +#if 1 // test-only
> +	offset = offset * 2;
> +#endif
>  	cp = flash_map (info, 0, offset);
>  #if defined(__LITTLE_ENDIAN) || defined(CONFIG_SYS_WRITE_SWAPPED_DATA)
>  	retval = flash_read8(cp);
> @@ -308,6 +311,9 @@ static inline ushort flash_read_word (flash_info_t *
> info, uint offset)
>  {
>  	ushort *addr, retval;
> 
> +#if 1 // test-only
> +	offset = offset * 2;
> +#endif
>  	addr = flash_map (info, 0, offset);
>  	retval = flash_read16 (addr);
>  	flash_unmap (info, 0, offset, addr);
> @@ -328,6 +334,9 @@ static ulong flash_read_long (flash_info_t * info,
> flash_sect_t sect,
>  #ifdef DEBUG
>  	int x;
>  #endif
> +#if 1 // test-only
> +	offset = offset * 2;
> +#endif
>  	addr = flash_map (info, sect, offset);
> 
>  #ifdef DEBUG
> @@ -363,6 +372,9 @@ void flash_write_cmd (flash_info_t * info,
> flash_sect_t sect,
>  	void *addr;
>  	cfiword_t cword;
> 
> +#if 1 // test-only
> +	offset = offset * 2;
> +#endif
>  	addr = flash_map (info, sect, offset);
>  	flash_make_cmd (info, cmd, &cword);
>  	switch (info->portwidth) {
> @@ -420,6 +432,9 @@ static int flash_isequal (flash_info_t * info,
> flash_sect_t sect,
>  	cfiword_t cword;
>  	int retval;
> 
> +#if 1 // test-only
> +	offset = offset * 2;
> +#endif
>  	addr = flash_map (info, sect, offset);
>  	flash_make_cmd (info, cmd, &cword);
> 
> @@ -1762,6 +1777,7 @@ static int __flash_detect_cfi (flash_info_t *
> info, struct cfi_qry *qry)
>  			info->addr_unlock1 = 0x555;
>  			info->addr_unlock2 = 0x2aa;
> 
> +#if 0 // test-only
>  			/*
>  			 * modify the unlock address if we are
>  			 * in compatibility mode
> @@ -1776,6 +1792,7 @@ static int __flash_detect_cfi (flash_info_t *
> info, struct cfi_qry *qry)
>  				info->addr_unlock1 = 0xaaa;
>  				info->addr_unlock2 = 0x555;
>  			}
> +#endif
> 
>  			info->name = "CFI conformant";
>  			return 1;
> @@ -1942,11 +1959,13 @@ ulong flash_get_size (phys_addr_t base, int
> banknum) debug ("cfi version is 0x%04x\n", info->cfi_version);
> 
>  		size_ratio = info->portwidth / info->chipwidth;
> +#if 0 // test-only
>  		/* if the chip is x8/x16 reduce the ratio by half */
>  		if ((info->interface == FLASH_CFI_X8X16)
>  		    && (info->chipwidth == FLASH_CFI_BY8)) {
>  			size_ratio >>= 1;
>  		}
> +#endif
>  		debug ("size_ratio %d port %d bits chip %d bits\n",
>  		       size_ratio, info->portwidth << CFI_FLASH_SHIFT_WIDTH,
>  		       info->chipwidth << CFI_FLASH_SHIFT_WIDTH);
> @@ -2034,12 +2053,13 @@ ulong flash_get_size (phys_addr_t base, int
> banknum) /* round up when converting to ms */
>  		info->write_tout = (tmp + 999) / 1000;
>  		info->flash_id = FLASH_MAN_CFI;
> +#if 0
>  		if ((info->interface == FLASH_CFI_X8X16) &&
>  		    (info->chipwidth == FLASH_CFI_BY8)) {
>  			/* XXX - Need to test on x8/x16 in parallel. */
>  			info->portwidth >>= 1;
>  		}
> -
> +#endif
>  		flash_write_cmd (info, 0, 0, info->cmd_reset);
>  	}