Re: [PATCH v6 2/8] mtd: rawnand: rockchip: NFC drivers for RK3308, RK2928 and others

Miquel Raynal
2020-06-15T07:47:10Z

Hi Johan,

Johan Jonker <jbx6244@gmail.com> wrote on Sat, 13 Jun 2020 15:31:52
+0200:

> Hi Yifeng, Miquel,
>
> Some more comments about swap();
>
> On 6/9/20 9:40 AM, Yifeng Zhao wrote:
>
> [..]
>
> > +static int rk_nfc_ooblayout_free(struct mtd_info *mtd, int section,
> > + struct mtd_oob_region *oob_region)
> > +{
> > + struct nand_chip *chip = mtd_to_nand(mtd);
> > +
>
> > + if (section >= chip->ecc.steps)
> > + return -ERANGE;
>
> Given:
>
> NFC_SYS_DATA_SIZE = 4
> chip->ecc.steps = 8
> section [0..7]
>
> Total free OOB size advertised to the MTD framework is:
>
> ecc.steps * NFC_SYS_DATA_SIZE - 1 BBM
> 8 * 4 - 1 = 31 bytes
>
> With link address in OOB byte [0..3] this become:
> 31 - 4 = 27 bytes
>
> Does that give data lost?
> Should we limit the number of free OOB bytes by 4 more to be save?
> Is my calculation correct?

I don't know what link address is, but yes if it's an area used by the
controller for whatever reason it should be left alone, neither "free"
nor "ecc".

>
> See further questions about this below.
>
> > +
> > + if (!section) {
> > + /* The first byte is bad block mask flag. */
> > + oob_region->length = NFC_SYS_DATA_SIZE - 1;
> > + oob_region->offset = 1;
> > + } else {
> > + oob_region->length = NFC_SYS_DATA_SIZE;
> > + oob_region->offset = section * NFC_SYS_DATA_SIZE;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static int rk_nfc_ooblayout_ecc(struct mtd_info *mtd, int section,
> > + struct mtd_oob_region *oob_region)
> > +{
> > + struct nand_chip *chip = mtd_to_nand(mtd);
> > +
>
> > + if (section)
> > + return -ERANGE;
>
> With the formule above a section > 0 does not alow ECC.
>
> Just a question about the MTD inner working for Miquel:
>
> With ooblayout_free using 8 steps and this just 1 does it still generate
> the correct ECC? Does it calculate ECC over 1024B or over 8*1024B ?

These functions do not generate anything and it's just a helper to
retrieve the ECC or free bytes, meaning that if you have 4 ECC bytes
per step, all concatenated, you will end with with an unique ECC
section of 8 * 4 ECC bytes, this is perfectly fine.

>
> Should we move the text that explains the layout closer to these
> functions and add a little more text to explain why we choose this
> particular layout?

Yes please.

>
> /*
> * NFC Page Data Layout:
> * 1024 Bytes Data + 4Bytes sys data + 28Bytes~124Bytes ecc +
> * 1024 Bytes Data + 4Bytes sys data + 28Bytes~124Bytes ecc +
> * ......
> * NAND Page Data Layout:
> * 1024 * n Data + m Bytes oob
> * Original Bad Block Mask Location:
> * First byte of oob(spare).
> * nand_chip->oob_poi data layout:
> * 4Bytes sys data + .... + 4Bytes sys data + ecc data.
> */
>
> We expect now ECC data after n steps * 4 OOB bytes,

fine

> but are we still using it with HW ECC or only for raw?

both, you need to ensure reading a raw pages gives you a regular
data+ecc organization instead of the NFC's layout.

>
> > +
> > + oob_region->offset = NFC_SYS_DATA_SIZE * chip->ecc.steps;
> > + oob_region->length = mtd->oobsize - oob_region->offset;
> > +
> > + return 0;
> > +}
> > +
> > +static const struct mtd_ooblayout_ops rk_nfc_ooblayout_ops = {
> > + .free = rk_nfc_ooblayout_free,
> > + .ecc = rk_nfc_ooblayout_ecc,
> > +};
>
> [..]
>
> > +static int rk_nfc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
> > + const u8 *buf, int page, int raw)
> > +{
> > + struct rk_nfc *nfc = nand_get_controller_data(chip);
> > + struct rk_nfc_nand_chip *rk_nand = to_rk_nand(chip);
> > + struct nand_ecc_ctrl *ecc = &chip->ecc;
> > + int oob_step = (ecc->bytes > 60) ? NFC_MAX_OOB_PER_STEP :
> > + NFC_MIN_OOB_PER_STEP;
> > + int pages_per_blk = mtd->erasesize / mtd->writesize;
> > + int ret = 0, i, boot_rom_mode = 0;
> > + dma_addr_t dma_data, dma_oob;
> > + u32 reg;
> > + u8 *oob;
> > +
> > + nand_prog_page_begin_op(chip, page, 0, NULL, 0);
> > +
> > + if (!raw) {
> > + memcpy(nfc->page_buf, buf, mtd->writesize);
> > + memset(nfc->oob_buf, 0xff, oob_step * ecc->steps);
> > +
> > + /*
> > + * The first 8(some devices are 4 or 16) blocks in use by
> > + * the boot ROM and the first 32 bits of oob need to link
> > + * to the next page address in the same block.
> > + * Config the ECC algorithm supported by the boot ROM.
> > + */
> > + if (page < pages_per_blk * rk_nand->boot_blks &&
> > + chip->options & NAND_IS_BOOT_MEDIUM) {
> > + boot_rom_mode = 1;
> > + if (rk_nand->boot_ecc != ecc->strength)
> > + rk_nfc_hw_ecc_setup(chip, ecc,
> > + rk_nand->boot_ecc);
> > + }
> > +
> > + /*
> > + * Swap the first oob with the seventh oob and bad block
> > + * mask is saved at the seventh oob.
> > + */
> > + swap(chip->oob_poi[0], chip->oob_poi[7]);
>
> Add more info on why this is swapped.
>
> LA[0..3] is a link address that the BBM shouldn't over write.
> For Yifeng: Is there an other reason?
>
> Before swap:
>
> BBM OOB1 OOB2 OOB3, OOB4 OOB5 OOB6 OOB7, OOB8 ....
>
> After swap:
>
> OOB7 OOB1 OOB2 OOB3, OOB4 OOB5 OOB6 BBM , OOB8 ....
>
> If (!i && boot_rom_mode):
>
> LA0 LA1 LA2 LA3 , OOB4 OOB5 OOB6 BBM , OOB8 ....
>
> Read back after swap again:
>
> BBM LA1 LA2 LA3 , OOB4 OOB5 OOB6 LA0 , OOB8 ....
>
> Question:
> Are data OOB7 OOB1 OOB2 OOB3 lost now?
> Is this correct?
>
> #################################################
> Proposal:
> Should we reduce the free OOB size by 4
> and shift everything 4 bytes to recover all bytes?
> Replace the first 4 bytes with 0XFF or LA[0..3].
>
> Normal:
> 0xFF 0XFF 0XFF 0xFF, BBM OOB1 OOB2 OOB3, OOB4
>
> If (!i && boot_rom_mode):
> LA0 LA1 LA2 LA3 , BBM OOB1 OOB2 OOB3, OOB4
>
> Question for Miquel and Yifeng:
> Does this work? Could you test?
>
> > +
> > + for (i = 0; i < ecc->steps; i++) {
>
> Just a proposel:
>
> if (!i && boot_rom_mode)
> reg = (page & (pages_per_blk - 1)) * 4;
> else if (!i)
> reg = 0xFFFFFFFF;
> else
> oob = chip->oob_poi + (i-1) * NFC_SYS_DATA_SIZE;
> reg = oob[0] | oob[1] << 8 | oob[2] << 16 |
> oob[3] << 24;
>
> > +
> > + if (nfc->cfg->type == NFC_V6 ||
> > + nfc->cfg->type == NFC_V8)
> > + nfc->oob_buf[i * oob_step / 4] = reg;
> > + else
> > + nfc->oob_buf[i] = reg;
> > + }
> > +
> > + dma_data = dma_map_single(nfc->dev, (void *)nfc->page_buf,
> > + mtd->writesize, DMA_TO_DEVICE);
> > + dma_oob = dma_map_single(nfc->dev, nfc->oob_buf,
> > + ecc->steps * oob_step,
> > + DMA_TO_DEVICE);
> > +
> > + reinit_completion(&nfc->done);
> > + writel(INT_DMA, nfc->regs + nfc->cfg->int_en_off);
> > +
> > + rk_nfc_xfer_start(nfc, NFC_WRITE, ecc->steps, dma_data,
> > + dma_oob);
> > + ret = wait_for_completion_timeout(&nfc->done,
> > + msecs_to_jiffies(100));
> > + if (!ret)
> > + dev_warn(nfc->dev, "write: wait dma done timeout.\n");
> > + /*
> > + * Whether the DMA transfer is completed or not. The driver
> > + * needs to check the NFC`s status register to see if the data
> > + * transfer was completed.
> > + */
> > + ret = rk_nfc_wait_for_xfer_done(nfc);
> > +
> > + dma_unmap_single(nfc->dev, dma_data, mtd->writesize,
> > + DMA_TO_DEVICE);
> > + dma_unmap_single(nfc->dev, dma_oob, ecc->steps * oob_step,
> > + DMA_TO_DEVICE);
> > +
> > + if (boot_rom_mode && rk_nand->boot_ecc != ecc->strength)
> > + rk_nfc_hw_ecc_setup(chip, ecc, ecc->strength);
> > +
> > + if (ret) {
> > + ret = -EIO;
> > + dev_err(nfc->dev,
> > + "write: wait transfer done timeout.\n");
> > + }
> > + } else {
> > + rk_nfc_write_buf(chip, buf, mtd->writesize + + mtd->oobsize);
>
> Remove a '+'
>
> > + }
> > +
> > + if (ret)
> > + return ret;
> > +
> > + ret = nand_prog_page_end_op(chip);
> > +
> > + /* Deselect the currently selected target. */
> > + rk_nfc_select_chip(chip, -1);
> > +
> > + return ret;
> > +}
> > +
> > +static int rk_nfc_write_page_raw(struct nand_chip *chip, const u8 *buf,
> > + int oob_on, int page)
> > +{
> > + struct mtd_info *mtd = nand_to_mtd(chip);
> > + struct rk_nfc *nfc = nand_get_controller_data(chip);
> > + u32 i;
> > +
> > + memset(nfc->buffer, 0xff, mtd->writesize + mtd->oobsize);
> > + swap(chip->oob_poi[0], chip->oob_poi[7]);
> > + for (i = 0; i < chip->ecc.steps; i++) {
> > + if (buf)
> > + memcpy(rk_data_ptr(chip, i), data_ptr(chip, buf, i),
> > + chip->ecc.size);
> > +
> > + memcpy(rk_oob_ptr(chip, i), oob_ptr(chip, i),
> > + NFC_SYS_DATA_SIZE);
> > + }
> > +
> > + return rk_nfc_write_page(mtd, chip, nfc->buffer, page, 1);
> > +}
> > +
> > +static int rk_nfc_write_oob_std(struct nand_chip *chip, int page)
> > +{
> > + return rk_nfc_write_page_raw(chip, NULL, 1, page);
> > +}
> > +
> > +static int rk_nfc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
> > + u32 data_offs, u32 readlen,
> > + u8 *buf, int page, int raw)
> > +{
> > + struct rk_nfc *nfc = nand_get_controller_data(chip);
> > + struct rk_nfc_nand_chip *rk_nand = to_rk_nand(chip);
> > + struct nand_ecc_ctrl *ecc = &chip->ecc;
> > + int oob_step = (ecc->bytes > 60) ? NFC_MAX_OOB_PER_STEP :
> > + NFC_MIN_OOB_PER_STEP;
> > + int pages_per_blk = mtd->erasesize / mtd->writesize;
> > + dma_addr_t dma_data, dma_oob;
> > + int ret = 0, i, boot_rom_mode = 0;
> > + int bitflips = 0, bch_st;
> > + u8 *oob;
> > + u32 tmp;
> > +
> > + nand_read_page_op(chip, page, 0, NULL, 0);
> > + if (!raw) {
> > + dma_data = dma_map_single(nfc->dev, nfc->page_buf,
> > + mtd->writesize,
> > + DMA_FROM_DEVICE);
> > + dma_oob = dma_map_single(nfc->dev, nfc->oob_buf,
> > + ecc->steps * oob_step,
> > + DMA_FROM_DEVICE);
> > +
> > + /*
> > + * The first 8(some devices are 4 or 16) blocks in use by
> > + * the bootrom.
> > + * Config the ECC algorithm supported by the boot ROM.
> > + */
> > + if (page < pages_per_blk * rk_nand->boot_blks &&
> > + chip->options & NAND_IS_BOOT_MEDIUM) {
> > + boot_rom_mode = 1;
> > + if (rk_nand->boot_ecc != ecc->strength)
> > + rk_nfc_hw_ecc_setup(chip, ecc,
> > + rk_nand->boot_ecc);
> > + }
> > +
> > + reinit_completion(&nfc->done);
> > + writel(INT_DMA, nfc->regs + nfc->cfg->int_en_off);
> > + rk_nfc_xfer_start(nfc, NFC_READ, ecc->steps, dma_data,
> > + dma_oob);
> > + ret = wait_for_completion_timeout(&nfc->done,
> > + msecs_to_jiffies(100));
> > + if (!ret)
> > + dev_warn(nfc->dev, "read: wait dma done timeout.\n");
> > + /*
> > + * Whether the DMA transfer is completed or not. The driver
> > + * needs to check the NFC`s status register to see if the data
> > + * transfer was completed.
> > + */
> > + ret = rk_nfc_wait_for_xfer_done(nfc);
> > + dma_unmap_single(nfc->dev, dma_data, mtd->writesize,
> > + DMA_FROM_DEVICE);
> > + dma_unmap_single(nfc->dev, dma_oob, ecc->steps * oob_step,
> > + DMA_FROM_DEVICE);
> > +
> > + if (ret) {
> > + bitflips = -EIO;
> > + dev_err(nfc->dev,
> > + "read: wait transfer done timeout.\n");
> > + goto out;
> > + }
> > +
> > + for (i = 0; i < ecc->steps; i++) {
> > + oob = chip->oob_poi + i * NFC_SYS_DATA_SIZE;
> > + if (nfc->cfg->type == NFC_V6 ||
> > + nfc->cfg->type == NFC_V8)
> > + tmp = nfc->oob_buf[i * oob_step / 4];
> > + else
> > + tmp = nfc->oob_buf[i];
> > + *oob++ = (u8)tmp;
> > + *oob++ = (u8)(tmp >> 8);
> > + *oob++ = (u8)(tmp >> 16);
> > + *oob++ = (u8)(tmp >> 24);
> > + }
> > +
> > + /*
> > + * Swap the first oob with the seventh oob and bad block
> > + * mask is saved at the seventh oob.
> > + */
> > + swap(chip->oob_poi[0], chip->oob_poi[7]);
> > +
> > + for (i = 0; i < ecc->steps / 2; i++) {
> > + bch_st = readl_relaxed(nfc->regs +
> > + nfc->cfg->bch_st_off + i * 4);
> > + if (bch_st & BIT(nfc->cfg->ecc0.err_flag_bit) ||
> > + bch_st & BIT(nfc->cfg->ecc1.err_flag_bit)) {
> > + mtd->ecc_stats.failed++;
> > + bitflips = -1;
> > + } else {
> > + ret = ECC_ERR_CNT(bch_st, nfc->cfg->ecc0);
> > + mtd->ecc_stats.corrected += ret;
> > + bitflips = max_t(u32, bitflips, ret);
> > +
> > + ret = ECC_ERR_CNT(bch_st, nfc->cfg->ecc1);
> > + mtd->ecc_stats.corrected += ret;
> > + bitflips = max_t(u32, bitflips, ret);
> > + }
> > + }
> > +out:
> > + memcpy(buf, nfc->page_buf, mtd->writesize);
> > +
> > + if (boot_rom_mode && rk_nand->boot_ecc != ecc->strength)
> > + rk_nfc_hw_ecc_setup(chip, ecc, ecc->strength);
> > +
> > + if (bitflips < 0)
> > + dev_err(nfc->dev, "read page: %x ecc error!\n", page);
> > + } else {
> > + rk_nfc_read_buf(chip, buf, mtd->writesize + mtd->oobsize);
> > + }
> > + /* Deselect the currently selected target. */
> > + rk_nfc_select_chip(chip, -1);
> > +
> > + return bitflips;
> > +}
> > +
> > +static int rk_nfc_write_page_hwecc(struct nand_chip *chip, const u8 *buf,
> > + int oob_on, int page)
> > +{
> > + return rk_nfc_write_page(nand_to_mtd(chip), chip, buf, page, 0);
> > +}
> > +
> > +static int rk_nfc_read_page_hwecc(struct nand_chip *chip, u8 *p, int oob_on,
> > + int pg)
> > +{
> > + struct mtd_info *mtd = nand_to_mtd(chip);
> > +
> > + return rk_nfc_read_page(mtd, chip, 0, mtd->writesize, p, pg, 0);
> > +}
> > +
> > +static int rk_nfc_read_page_raw(struct nand_chip *chip, u8 *buf, int oob_on,
> > + int page)
> > +{
> > + struct mtd_info *mtd = nand_to_mtd(chip);
> > + struct rk_nfc *nfc = nand_get_controller_data(chip);
> > + int i, ret;
> > +
> > + ret = rk_nfc_read_page(mtd, chip, 0, mtd->writesize, nfc->buffer,
> > + page, 1);
> > + if (ret < 0)
> > + return ret;
> > +
> > + for (i = 0; i < chip->ecc.steps; i++) {
> > + memcpy(oob_ptr(chip, i), rk_oob_ptr(chip, i),
> > + NFC_SYS_DATA_SIZE);
> > +
> > + if (buf)
> > + memcpy(data_ptr(chip, buf, i), rk_data_ptr(chip, i),
> > + chip->ecc.size);
> > + }
> > + swap(chip->oob_poi[0], chip->oob_poi[7]);
> > +
> > + return ret;
> > +}
>
> [..]

Thanks,
Miquèl