From 11d5655919ab94f4452f45f1a1b38a6a30030705 Mon Sep 17 00:00:00 2001 From: Pratyush Yadav Date: Tue, 4 Jun 2024 11:39:10 +0530 Subject: [PATCH] mtd: spi-nor-core: Do not start or end writes at odd address in DTR mode On DTR capable flashes like Micron Xcella the writes cannot start or end at an odd address in DTR mode. Extra 0xff bytes need to be prepended or appended respectively to make sure both the start and end addresses are even. Signed-off-by: Pratyush Yadav Signed-off-by: Apurva Nandan Signed-off-by: Vignesh Raghavendra Tested-by: Jonathan Humphreys Signed-off-by: Manorit Chawdhry --- drivers/mtd/spi/spi-nor-core.c | 59 +++++++++++++++++++++++++++++++--- 1 file changed, 55 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c index 982dd25115..aea611fef5 100644 --- a/drivers/mtd/spi/spi-nor-core.c +++ b/drivers/mtd/spi/spi-nor-core.c @@ -1804,11 +1804,62 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len, if (ret < 0) return ret; #endif + write_enable(nor); - ret = nor->write(nor, addr, page_remain, buf + i); - if (ret < 0) - goto write_err; - written = ret; + + /* + * On DTR capable flashes like Micron Xcella the writes cannot + * start or end at an odd address in DTR mode. So we need to + * append or prepend extra 0xff bytes to make sure the start + * address and end address are even. + */ + if (spi_nor_protocol_is_dtr(nor->write_proto) && + ((addr | page_remain) & 1)) { + u_char *tmp; + size_t extra_bytes = 0; + + tmp = kmalloc(nor->page_size, 0); + if (!tmp) { + ret = -ENOMEM; + goto write_err; + } + + /* Prepend a 0xff byte if the start address is odd. */ + if (addr & 1) { + tmp[0] = 0xff; + memcpy(tmp + 1, buf + i, page_remain); + addr--; + page_remain++; + extra_bytes++; + } else { + memcpy(tmp, buf + i, page_remain); + } + + /* Append a 0xff byte if the end address is odd. */ + if ((addr + page_remain) & 1) { + tmp[page_remain + extra_bytes] = 0xff; + extra_bytes++; + page_remain++; + } + + ret = nor->write(nor, addr, page_remain, tmp); + + kfree(tmp); + + if (ret < 0) + goto write_err; + + /* + * We write extra bytes but they are not part of the + * original write. + */ + written = ret - extra_bytes; + } else { + ret = nor->write(nor, addr, page_remain, buf + i); + if (ret < 0) + goto write_err; + written = ret; + } ret = spi_nor_wait_till_ready(nor); if (ret) -- 2.39.5