Re: [PATCH v5 1/3] mtd: nand: raw: qcom_nandc: add support for unprotected spare data pages

Manivannan Sadhasivam
2022-06-09T07:53:47Z

On Wed, Jun 08, 2022 at 02:10:28AM +0200, Ansuel Smith wrote:
> IPQ8064 nand have special pages where a different layout scheme is used.
> These special page are used by boot partition and on reading them
> lots of warning are reported about wrong ECC data and if written to
> results in broken data and not bootable device.
>
> The layout scheme used by these special page consist in using 512 bytes
> as the codeword size (even for the last codeword) while writing to CFG0
> register. This forces the NAND controller to unprotect the 4 bytes of
> spare data.
>
> Since the kernel is unaware of this different layout for these special
> page, it does try to protect the spare data too during read/write and
> warn about CRC errors.
>
> Add support for this by permitting the user to declare these special
> pages in dts by declaring offset and size of the partition. The driver
> internally will convert these value to nand pages.
>
> On user read/write the page is checked and if it's a boot page the
> correct layout is used.
>
> Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> ---
> drivers/mtd/nand/raw/qcom_nandc.c | 174 +++++++++++++++++++++++++++++-
> 1 file changed, 169 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index 1a77542c6d67..06ee9a836a3b 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -80,8 +80,10 @@
> #define DISABLE_STATUS_AFTER_WRITE 4
> #define CW_PER_PAGE 6
> #define UD_SIZE_BYTES 9
> +#define UD_SIZE_BYTES_MASK GENMASK(18, 9)
> #define ECC_PARITY_SIZE_BYTES_RS 19
> #define SPARE_SIZE_BYTES 23
> +#define SPARE_SIZE_BYTES_MASK GENMASK(26, 23)
> #define NUM_ADDR_CYCLES 27
> #define STATUS_BFR_READ 30
> #define SET_RD_MODE_AFTER_STATUS 31
> @@ -102,6 +104,7 @@
> #define ECC_MODE 4
> #define ECC_PARITY_SIZE_BYTES_BCH 8
> #define ECC_NUM_DATA_BYTES 16
> +#define ECC_NUM_DATA_BYTES_MASK GENMASK(25, 16)
> #define ECC_FORCE_CLK_OPEN 30
>
> /* NAND_DEV_CMD1 bits */
> @@ -418,6 +421,19 @@ struct qcom_nand_controller {
> const struct qcom_nandc_props *props;
> };
>
> +/*
> + * NAND special boot partitions
> + *
> + * @page_offset: offset of the partition where spare data is not protected
> + * by ECC (value in pages)

s/page_offset/offset

> + * @page_offset: size of the partition where spare data is not protected
> + * by ECC (value in pages)

s/page_offset/size

> + */
> +struct qcom_nand_boot_partition {
> + u32 page_offset;
> + u32 page_size;

same here

> +};
> +
> /*
> * NAND chip structure
> *
> @@ -444,6 +460,13 @@ struct qcom_nand_controller {
> * @cfg0, cfg1, cfg0_raw..: NANDc register configurations needed for
> * ecc/non-ecc mode for the current nand flash
> * device
> + *
> + * @codeword_fixup: keep track of the current layout used by
> + * the driver for read/write operation.
> + * @nr_boot_partitions: count of the boot partitions where spare data is not
> + * protected by ECC

Align the Kdoc comments w.r.t other members.

> + * @boot_pages: array of boot partitions where offset and size of the
> + * boot partitions are stored

s/boot_pages/boot_partitions

> */
> struct qcom_nand_host {
> struct nand_chip chip;
> @@ -466,6 +489,10 @@ struct qcom_nand_host {
> u32 ecc_bch_cfg;
> u32 clrflashstatus;
> u32 clrreadstatus;
> +
> + bool codeword_fixup;
> + int nr_boot_partitions;
> + struct qcom_nand_boot_partition *boot_partitions;
> };
>
> /*
> @@ -475,6 +502,7 @@ struct qcom_nand_host {
> * @is_bam - whether NAND controller is using BAM
> * @is_qpic - whether NAND CTRL is part of qpic IP
> * @qpic_v2 - flag to indicate QPIC IP version 2
> + * @use_codeword_fixup - whether NAND has different layout for boot partitions
> * @dev_cmd_reg_start - NAND_DEV_CMD_* registers starting offset
> */
> struct qcom_nandc_props {
> @@ -482,6 +510,7 @@ struct qcom_nandc_props {
> bool is_bam;
> bool is_qpic;
> bool qpic_v2;
> + bool use_codeword_fixup;
> u32 dev_cmd_reg_start;
> };
>
> @@ -1701,7 +1730,7 @@ qcom_nandc_read_cw_raw(struct mtd_info *mtd, struct nand_chip *chip,
> data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
> oob_size1 = host->bbm_size;
>
> - if (qcom_nandc_is_last_cw(ecc, cw)) {
> + if (qcom_nandc_is_last_cw(ecc, cw) && !host->codeword_fixup) {
> data_size2 = ecc->size - data_size1 -
> ((ecc->steps - 1) * 4);
> oob_size2 = (ecc->steps * 4) + host->ecc_bytes_hw +
> @@ -1782,7 +1811,7 @@ check_for_erased_page(struct qcom_nand_host *host, u8 *data_buf,
> }
>
> for_each_set_bit(cw, &uncorrectable_cws, ecc->steps) {
> - if (qcom_nandc_is_last_cw(ecc, cw)) {
> + if (qcom_nandc_is_last_cw(ecc, cw) && !host->codeword_fixup) {
> data_size = ecc->size - ((ecc->steps - 1) * 4);
> oob_size = (ecc->steps * 4) + host->ecc_bytes_hw;
> } else {
> @@ -1940,7 +1969,7 @@ static int read_page_ecc(struct qcom_nand_host *host, u8 *data_buf,
> for (i = 0; i < ecc->steps; i++) {
> int data_size, oob_size;
>
> - if (qcom_nandc_is_last_cw(ecc, i)) {
> + if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
> data_size = ecc->size - ((ecc->steps - 1) << 2);
> oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
> host->spare_bytes;
> @@ -2037,6 +2066,55 @@ static int copy_last_cw(struct qcom_nand_host *host, int page)
> return ret;
> }
>
> +static bool
> +qcom_nandc_is_boot_page(struct qcom_nand_host *host, int page)

Move function name to previous line. If it exceeds 100 lines then wrap
arguments.

s/qcom_nandc_is_boot_page/qcom_nandc_is_boot_partition

> +{
> + struct qcom_nand_boot_partition *boot_partition;
> + u32 start, end;
> + int i;
> +
> + for (i = 0; i < host->nr_boot_partitions; i++) {
> + boot_partition = &host->boot_partitions[i];
> + start = boot_partition->page_offset;
> + end = start + boot_partition->page_size;
> +
> + /* Boot pages are normally at the start of

Block comments should start with:

/*
* ...

Also, are you sure that only few pages in the partitions have different layout
and not all pages? If not, then this comment needs to be reworded.

> + * the nand in various partition.
> + * Check the page from the boot page end first
> + * to save one extra check and optimize this
> + * in case real no-boot partition are used.
> + */
> + if (page < end && page >= start)
> + return true;
> + }
> +
> + return false;
> +}
> +
> +static void
> +qcom_nandc_codeword_fixup(struct qcom_nand_host *host, int page)
> +{
> + bool codeword_fixup = qcom_nandc_is_boot_page(host, page);
> +
> + /* Skip conf write if we are already in the correct mode */
> + if (codeword_fixup == host->codeword_fixup)
> + return;
> +
> + host->codeword_fixup = codeword_fixup;
> +
> + host->cw_data = codeword_fixup ? 512 : 516;
> + host->spare_bytes = host->cw_size - host->ecc_bytes_hw -
> + host->bbm_size - host->cw_data;
> +
> + host->cfg0 &= ~(SPARE_SIZE_BYTES_MASK | UD_SIZE_BYTES_MASK);
> + host->cfg0 |= host->spare_bytes << SPARE_SIZE_BYTES |
> + host->cw_data << UD_SIZE_BYTES;
> +
> + host->ecc_bch_cfg &= ~ECC_NUM_DATA_BYTES_MASK;
> + host->ecc_bch_cfg |= host->cw_data << ECC_NUM_DATA_BYTES;
> + host->ecc_buf_cfg = (codeword_fixup ? 0x1ff : 0x203) << NUM_STEPS;

s/1ff/(512 - 1)
s/203/(516 - 1)

> +}
> +
> /* implements ecc->read_page() */
> static int qcom_nandc_read_page(struct nand_chip *chip, uint8_t *buf,
> int oob_required, int page)
> @@ -2045,6 +2123,9 @@ static int qcom_nandc_read_page(struct nand_chip *chip, uint8_t *buf,
> struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> u8 *data_buf, *oob_buf = NULL;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> nand_read_page_op(chip, page, 0, NULL, 0);
> data_buf = buf;
> oob_buf = oob_required ? chip->oob_poi : NULL;
> @@ -2064,6 +2145,9 @@ static int qcom_nandc_read_page_raw(struct nand_chip *chip, uint8_t *buf,
> int cw, ret;
> u8 *data_buf = buf, *oob_buf = chip->oob_poi;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> for (cw = 0; cw < ecc->steps; cw++) {
> ret = qcom_nandc_read_cw_raw(mtd, chip, data_buf, oob_buf,
> page, cw);
> @@ -2084,6 +2168,9 @@ static int qcom_nandc_read_oob(struct nand_chip *chip, int page)
> struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> struct nand_ecc_ctrl *ecc = &chip->ecc;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> clear_read_regs(nandc);
> clear_bam_transaction(nandc);
>
> @@ -2104,6 +2191,9 @@ static int qcom_nandc_write_page(struct nand_chip *chip, const uint8_t *buf,
> u8 *data_buf, *oob_buf;
> int i, ret;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> nand_prog_page_begin_op(chip, page, 0, NULL, 0);
>
> clear_read_regs(nandc);
> @@ -2119,7 +2209,7 @@ static int qcom_nandc_write_page(struct nand_chip *chip, const uint8_t *buf,
> for (i = 0; i < ecc->steps; i++) {
> int data_size, oob_size;
>
> - if (qcom_nandc_is_last_cw(ecc, i)) {
> + if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
> data_size = ecc->size - ((ecc->steps - 1) << 2);
> oob_size = (ecc->steps << 2) + host->ecc_bytes_hw +
> host->spare_bytes;
> @@ -2176,6 +2266,9 @@ static int qcom_nandc_write_page_raw(struct nand_chip *chip,
> u8 *data_buf, *oob_buf;
> int i, ret;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> nand_prog_page_begin_op(chip, page, 0, NULL, 0);
> clear_read_regs(nandc);
> clear_bam_transaction(nandc);
> @@ -2194,7 +2287,7 @@ static int qcom_nandc_write_page_raw(struct nand_chip *chip,
> data_size1 = mtd->writesize - host->cw_size * (ecc->steps - 1);
> oob_size1 = host->bbm_size;
>
> - if (qcom_nandc_is_last_cw(ecc, i)) {
> + if (qcom_nandc_is_last_cw(ecc, i) && !host->codeword_fixup) {
> data_size2 = ecc->size - data_size1 -
> ((ecc->steps - 1) << 2);
> oob_size2 = (ecc->steps << 2) + host->ecc_bytes_hw +
> @@ -2254,6 +2347,9 @@ static int qcom_nandc_write_oob(struct nand_chip *chip, int page)
> int data_size, oob_size;
> int ret;
>
> + if (host->nr_boot_partitions)
> + qcom_nandc_codeword_fixup(host, page);
> +
> host->use_ecc = true;
> clear_bam_transaction(nandc);
>
> @@ -2902,6 +2998,71 @@ static int qcom_nandc_setup(struct qcom_nand_controller *nandc)
>
> static const char * const probes[] = { "cmdlinepart", "ofpart", "qcomsmem", NULL };
>
> +static int qcom_nand_host_parse_boot_partitions(struct qcom_nand_controller *nandc,
> + struct qcom_nand_host *host,
> + struct device_node *dn)
> +{
> + struct nand_chip *chip = &host->chip;
> + struct mtd_info *mtd = nand_to_mtd(chip);
> + struct qcom_nand_boot_partition *boot_partition;
> + struct device *dev = nandc->dev;
> + int partitions_count, i, j, ret;
> +
> + if (!nandc->props->use_codeword_fixup)
> + return 0;

Move this check to caller as I suggested previously.

> +
> + if (!of_find_property(dn, "qcom,boot-partitions", NULL))
> + return 0;
> +
> + partitions_count = of_property_count_u32_elems(dn, "qcom,boot-partitions");
> + if (partitions_count < 0) {

partitions_count <= 0

> + dev_err(dev, "Error parsing boot partition.");

Add newline at the end of error message

> + return ret;
> + }
> +
> + host->nr_boot_partitions = partitions_count / 2;
> + host->boot_partitions = devm_kcalloc(dev, host->nr_boot_partitions,
> + sizeof(*host->boot_partitions), GFP_KERNEL);
> + if (!host->boot_partitions)

host->nr_boot_partitions = 0;

> + return -ENOMEM;
> +
> + for (i = 0, j = 0; i < host->nr_boot_partitions; i++, j += 2) {
> + boot_partition = &host->boot_partitions[i];
> +
> + ret = of_property_read_u32_index(dn, "qcom,boot-partitions", j,
> + &boot_partition->page_offset);
> + if (ret) {
> + dev_err(dev, "Error parsing boot partition offset at index %d", i);

Add newline at the end of error message. Do the same for all error prints.

> + return ret;
> + }
> +
> + if (boot_partition->page_offset % mtd->writesize) {
> + dev_err(dev, "Boot partition offset not multiple of writesize at index %i",
> + i);
> + return -EINVAL;
> + }
> + /* Convert offset to nand pages */

s/pages/partitions

> + boot_partition->page_offset /= mtd->writesize;

s/page_offset/offset

> +
> + ret = of_property_read_u32_index(dn, "qcom,boot-partitions", j + 1,
> + &boot_partition->page_size);
> + if (ret) {
> + dev_err(dev, "Error parsing boot partition size at index %d", i);
> + return ret;
> + }
> +
> + if (boot_partition->page_size % mtd->writesize) {

s/page_size/size here and below

> + dev_err(dev, "Boot partition size not multiple of writesize at index %i",
> + i);
> + return -EINVAL;
> + }
> + /* Convert size to nand pages */

s/pages/partitions

Thanks,
Mani

> + boot_partition->page_size /= mtd->writesize;
> + }
> +
> + return 0;
> +}
> +
> static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
> struct qcom_nand_host *host,
> struct device_node *dn)
> @@ -2970,6 +3131,8 @@ static int qcom_nand_host_init_and_register(struct qcom_nand_controller *nandc,
> if (ret)
> nand_cleanup(chip);
>
> + qcom_nand_host_parse_boot_partitions(nandc, host, dn);
> +
> return ret;
> }
>
> @@ -3135,6 +3298,7 @@ static int qcom_nandc_remove(struct platform_device *pdev)
> static const struct qcom_nandc_props ipq806x_nandc_props = {
> .ecc_modes = (ECC_RS_4BIT | ECC_BCH_8BIT),
> .is_bam = false,
> + .use_codeword_fixup = true,
> .dev_cmd_reg_start = 0x0,
> };
>
> --
> 2.36.1
>

--
மணிவண்ணன் சதாசிவம்