On 14 Aug 2014, stefan@agner.ch wrote:
This adds initial support for Freescale NFC (NAND Flash Controller) found in ARM Vybrid SoC's, Power Architecture MPC5125 and others. However, this driver is only tested on Vybrid.
Signed-off-by: Stefan Agner stefan@agner.ch
drivers/mtd/nand/Makefile | 1 + drivers/mtd/nand/vf610_nfc.c | 706 ++++++++++++++++++++++++++++++++++++++++++> + 2 files changed, 707 insertions(+) create mode 100644 drivers/mtd/nand/vf610_nfc.c
diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c new file mode 100644 index 0000000..3150ac1 --- /dev/null +++ b/drivers/mtd/nand/vf610_nfc.c @@ -0,0 +1,706 @@ +/*
- Copyright 2009-2014 Freescale Semiconductor, Inc. and others
[snip]
+/* Count the number of 0's in buff upto max_bits */ +static inline int count_written_bits(uint8_t *buff, int size, int max_bits) +{
- uint32_t *buff32 = (uint32_t *)buff;
- int k, written_bits = 0;
- for (k = 0; k < (size / 4); k++) {
written_bits += hweight32(~buff32[k]);if (written_bits > max_bits)break;- }
- return written_bits;
+}
That is a nice change.
+static inline int vf610_nfc_correct_data(struct mtd_info *mtd, u_char *dat) +{
- struct vf610_nfc *nfc = mtd_to_nfc(mtd);
- u8 ecc_status;
- u8 ecc_count;
- int flip;
- ecc_status = __raw_readb(nfc->regs + ECC_SRAM_ADDR * 8 + ECC_OFFSET);
- ecc_count = ecc_status & ECC_ERR_COUNT;
- if (!(ecc_status & ECC_STATUS_MASK))
return ecc_count;- /* If 'ecc_count' zero or less then buffer is all 0xff or erased. */
- flip = count_written_bits(dat, nfc->chip.ecc.size, ecc_count);
- /* ECC failed. */
- if (flip > ecc_count)
return -1;
Sorry, I missed this in version one of the patch. The original had,
< if (flip > ecc_count) { < nfc->page = -1; ---
if (flip > ecc_count)
522d508 < }
I can see why you removed this (nfc->page = -1). However, I think that higher layers may want to re-read on an error in case of un-stable bits? It is very little code to ensure a re-read in case of ECC failure. The 2nd physical read may pass whereas the first failed. This path is rare, but maybe important? A higher layer may migrate the data in this case; just as with a corrected bits. But maybe U-Boot will never do this?
- /* Erased page. */
- memset(dat, 0xff, nfc->chip.ecc.size);
- return 0;
+}
Regards, Bill Pringlemeir.