Hello, Can you please provide your comments on this patch.
Thanks, Balamanikandan On 29/06/21 12:46 pm, Balamanikandan Gunasundar wrote: > The command shall be used to induce bit errors in the nand page > manually. The code flips a bit in the specified offset without > changing the ECC. This helps to see how the software handles the > error. > > The patch is ported from > https://patchwork.ozlabs.org/project/uboot/patch/\ > 1325691123-19565-1-git-send-email-holger.bru...@keymile.com > > The implementation is inspired from > 'mtd-utils/nand-utils/nandflipbits.c' > > Signed-off-by: Balamanikandan Gunasundar > <balamanikandan.gunasun...@microchip.com> > --- > cmd/nand.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 124 insertions(+), 3 deletions(-) > > diff --git a/cmd/nand.c b/cmd/nand.c > index 5bda69e819..ea1b0f9434 100644 > --- a/cmd/nand.c > +++ b/cmd/nand.c > @@ -17,6 +17,10 @@ > * and/or modified under the terms of the GNU General Public License as > * published by the Free Software Foundation; either version 2 of the > * License, or (at your option) any later version. > + * > + * The function nand_biterror() in this file is inspired from > + * mtd-utils/nand-utils/nandflipbits.c which was released under GPLv2 > + * only > */ > > #include <common.h> > @@ -40,6 +44,116 @@ int find_dev_and_part(const char *id, struct mtd_device > **dev, > u8 *part_num, struct part_info **part); > #endif > > +#define MAX_NUM_PAGES 64 > + > +static int nand_biterror(struct mtd_info *mtd, ulong off, int bit) > +{ > + int ret = 0; > + int page = 0; > + ulong block_off; > + u_char *datbuf[MAX_NUM_PAGES]; /* Data and OOB */ > + u_char data; > + int pages_per_blk = mtd->erasesize / mtd->writesize; > + struct erase_info einfo; > + > + if (pages_per_blk > MAX_NUM_PAGES) { > + printf("Too many pages in one erase block\n"); > + return 1; > + } > + > + if (bit < 0 || bit > 7) { > + printf("bit position 0 to 7 is allowed\n"); > + return 1; > + } > + > + /* Allocate memory */ > + memset(datbuf, 0, sizeof(datbuf)); > + for (page = 0; page < pages_per_blk ; page++) { > + datbuf[page] = malloc(mtd->writesize + mtd->oobsize); > + if (!datbuf[page]) { > + printf("No memory for page buffer\n"); > + ret = -ENOMEM; > + goto free_memory; > + } > + } > + > + /* Align to erase block boundary */ > + block_off = off & (~(mtd->erasesize - 1)); > + > + /* Read out memory as first step */ > + for (page = 0; page < pages_per_blk ; page++) { > + struct mtd_oob_ops ops; > + loff_t addr = (loff_t)block_off; > + > + memset(&ops, 0, sizeof(ops)); > + ops.datbuf = datbuf[page]; > + ops.oobbuf = datbuf[page] + mtd->writesize; > + ops.len = mtd->writesize; > + ops.ooblen = mtd->oobsize; > + ops.mode = MTD_OPS_RAW; > + ret = mtd_read_oob(mtd, addr, &ops); > + if (ret < 0) { > + printf("Error (%d) reading page %08lx\n", > + ret, block_off); > + ret = 1; > + goto free_memory; > + } > + block_off += mtd->writesize; > + } > + > + /* Erase the block */ > + memset(&einfo, 0, sizeof(einfo)); > + einfo.mtd = mtd; > + /* Align to erase block boundary */ > + einfo.addr = (loff_t)(off & (~(mtd->erasesize - 1))); > + einfo.len = mtd->erasesize; > + ret = mtd_erase(mtd, &einfo); > + if (ret < 0) { > + printf("Error (%d) nand_erase_nand page %08llx\n", > + ret, einfo.addr); > + ret = 1; > + goto free_memory; > + } > + > + /* Twist a bit in data part */ > + block_off = off & (mtd->erasesize - 1); > + data = datbuf[block_off / mtd->writesize][block_off % mtd->writesize]; > + data ^= (1 << bit); > + datbuf[block_off / mtd->writesize][block_off % mtd->writesize] = data; > + > + printf("Flip data at 0x%lx with xor 0x%02x (bit=%d) to value=0x%02x\n", > + off, (1 << bit), bit, data); > + > + /* Write back twisted data and unmodified OOB */ > + /* Align to erase block boundary */ > + block_off = off & (~(mtd->erasesize - 1)); > + for (page = 0; page < pages_per_blk; page++) { > + struct mtd_oob_ops ops; > + loff_t addr = (loff_t)block_off; > + > + memset(&ops, 0, sizeof(ops)); > + ops.datbuf = datbuf[page]; > + ops.oobbuf = datbuf[page] + mtd->writesize; > + ops.len = mtd->writesize; > + ops.ooblen = mtd->oobsize; > + ops.mode = MTD_OPS_RAW; > + ret = mtd_write_oob(mtd, addr, &ops); > + if (ret < 0) { > + printf("Error (%d) write page %08lx\n", ret, block_off); > + ret = 1; > + goto free_memory; > + } > + block_off += mtd->writesize; > + } > + > +free_memory: > + for (page = 0; page < pages_per_blk ; page++) { > + if (datbuf[page]) > + free(datbuf[page]); > + } > + return ret; > +} > + > static int nand_dump(struct mtd_info *mtd, ulong off, int only_oob, > int repeat) > { > @@ -728,8 +842,15 @@ static int do_nand(cmd_tbl_t *cmdtp, int flag, int argc, > char * const argv[]) > } > > if (strcmp(cmd, "biterr") == 0) { > - /* todo */ > - return 1; > + int bit; > + > + if (argc != 4) > + goto usage; > + > + off = (int)simple_strtoul(argv[2], NULL, 16); > + bit = (int)simple_strtoul(argv[3], NULL, 10); > + ret = nand_biterror(mtd, off, bit); > + return ret; > } > > #ifdef CONFIG_CMD_NAND_LOCK_UNLOCK > @@ -820,7 +941,7 @@ static char nand_help_text[] = > "nand scrub [-y] off size | scrub.part partition | scrub.chip\n" > " really clean NAND erasing bad blocks (UNSAFE)\n" > "nand markbad off [...] - mark bad block(s) at offset (UNSAFE)\n" > - "nand biterr off - make a bit error at offset (UNSAFE)" > + "nand biterr off bit - make a bit error at offset and bit position > (UNSAFE)" > #ifdef CONFIG_CMD_NAND_LOCK_UNLOCK > "\n" > "nand lock [tight] [status]\n" >
