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

[Rogan Dawes]

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);
 	}

-- 
1.7.1