[PATCH v2 3/3] mtd: rawnand: meson: read/write access for boot ROM pages
Arseniy Krasnov
avkrasnov at salutedevices.com
Mon Aug 26 10:47:39 CEST 2024
On 26.08.2024 10:16, Michael Nazzareno Trimarchi wrote:
> Hi
>
> On Mon, Aug 26, 2024 at 8:17 AM Arseniy Krasnov
> <avkrasnov at salutedevices.com> wrote:
>>
>> Boot ROM on Meson needs some pages to be read/written in a special mode:
>> 384 byte ECC mode (so called "short" by Amlogic) and with scrambling
>> enabled. Such pages are located on the chip in the following way (for
>> example):
>>
>> [ p0 ][ p1 ][ p2 ][ p3 ][ p4 ][ p5 ][ p6 ][ p7 ] ... [ pN ]
>> ^ ^ ^ ^
>>
>> pX is page number "X". "^" means "special" page used by boot ROM - e.g.
>> every 2nd page in the range of [0, 7]. Step (2 here) and last page in
>> range is read from the device tree.
>>
>> Signed-off-by: Arseniy Krasnov <avkrasnov at salutedevices.com>
>> ---
>> drivers/mtd/nand/raw/meson_nand.c | 56 +++++++++++++++++++++++++------
>> 1 file changed, 46 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
>> index 19f005202b..54ea035d8d 100644
>> --- a/drivers/mtd/nand/raw/meson_nand.c
>> +++ b/drivers/mtd/nand/raw/meson_nand.c
>> @@ -40,6 +40,7 @@
>> #define NFC_CMD_RB BIT(20)
>> #define NFC_CMD_SCRAMBLER_ENABLE BIT(19)
>> #define NFC_CMD_SCRAMBLER_DISABLE 0
>> +#define NFC_CMD_SHORTMODE_ENABLE 1
>> #define NFC_CMD_SHORTMODE_DISABLE 0
>> #define NFC_CMD_RB_INT BIT(14)
>> #define NFC_CMD_RB_INT_NO_PIN ((0xb << 10) | BIT(18) | BIT(16))
>> @@ -78,6 +79,8 @@
>>
>> #define DMA_DIR(dir) ((dir) ? NFC_CMD_N2M : NFC_CMD_M2N)
>>
>> +#define NFC_SHORT_MODE_ECC_SZ 384
>> +
>> #define ECC_CHECK_RETURN_FF -1
>>
>> #define NAND_CE0 (0xe << 10)
>> @@ -141,6 +144,8 @@
>> struct meson_nfc_nand_chip {
>> struct list_head node;
>> struct nand_chip nand;
>> + u32 boot_pages;
>> + u32 boot_page_step;
>>
>> u32 bch_mode;
>> u8 *data_buf;
>> @@ -229,33 +234,46 @@ static void meson_nfc_cmd_seed(const struct meson_nfc *nfc, u32 seed)
>> nfc->reg_base + NFC_REG_CMD);
>> }
>>
>> +static int meson_nfc_is_boot_page(struct nand_chip *nand, int page)
>> +{
>> + const struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> +
>> + return (nand->options & NAND_IS_BOOT_MEDIUM) &&
>> + !(page % meson_chip->boot_page_step) &&
>> + (page < meson_chip->boot_pages);
>> +}
>> +
>> static void meson_nfc_cmd_access(struct nand_chip *nand, bool raw, bool dir, int page)
>> {
>> + const struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> struct mtd_info *mtd = nand_to_mtd(nand);
>> const struct meson_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
>> - const struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
>> - u32 bch = meson_chip->bch_mode, cmd;
>> int len = mtd->writesize, pagesize, pages;
>> int scrambler;
>> + u32 cmd;
>>
>> if (nand->options & NAND_NEED_SCRAMBLING)
>> scrambler = NFC_CMD_SCRAMBLER_ENABLE;
>> else
>> scrambler = NFC_CMD_SCRAMBLER_DISABLE;
>>
>
> scrambler depends on NAND_NEED_SCRAMBLING so suppose
> that is not set
>
> scrambler = NAND_NEED_SCRAMBLING;
>
>> - pagesize = nand->ecc.size;
>> -
>> if (raw) {
>> len = mtd->writesize + mtd->oobsize;
>> cmd = len | scrambler | DMA_DIR(dir);
>> - writel(cmd, nfc->reg_base + NFC_REG_CMD);
>> - return;
>> - }
>> + } else if (meson_nfc_is_boot_page(nand, page)) {
>
> Now here you seems that you don't care anymore about this option and check
> only meson_nfc_is_boot_page
>
> Is something am I missing?
Idea is the following IIUC: such boot pages could be read in ECC mode only with enabled scrambling -
otherwise we get ECC error. Or we need to read it in raw mode. So:
if (read page in raw mode) {
use scrambler as provided
} else if (read boot page in ECC mode) {
force scrambling mode + NFC_ECC_BCH8_1K + NFC_CMD_SHORTMODE_ENABLE
} else {
//we read non-boot page in ECC mode
use scrambler as provided
}
Thanks
>
> Michael
>
>> + pagesize = NFC_SHORT_MODE_ECC_SZ >> 3;
>> + pages = mtd->writesize / 512;
>>
>> - pages = len / nand->ecc.size;
>> + scrambler = NFC_CMD_SCRAMBLER_ENABLE;
>> + cmd = CMDRWGEN(DMA_DIR(dir), scrambler, NFC_ECC_BCH8_1K,
>> + NFC_CMD_SHORTMODE_ENABLE, pagesize, pages);
>> + } else {
>> + pagesize = nand->ecc.size >> 3;
>> + pages = len / nand->ecc.size;
>>
>> - cmd = CMDRWGEN(DMA_DIR(dir), scrambler, bch,
>> - NFC_CMD_SHORTMODE_DISABLE, pagesize, pages);
>> + cmd = CMDRWGEN(DMA_DIR(dir), scrambler, meson_chip->bch_mode,
>> + NFC_CMD_SHORTMODE_DISABLE, pagesize, pages);
>> + }
>>
>> if (scrambler == NFC_CMD_SCRAMBLER_ENABLE)
>> meson_nfc_cmd_seed(nfc, page);
>> @@ -1132,6 +1150,24 @@ static int meson_nfc_nand_chip_init(struct udevice *dev, struct meson_nfc *nfc,
>> goto err_chip_buf_free;
>> }
>>
>> + if (nand->options & NAND_IS_BOOT_MEDIUM) {
>> + ret = ofnode_read_u32(node, "amlogic,boot-pages",
>> + &meson_chip->boot_pages);
>> + if (ret) {
>> + dev_err(dev, "could not retrieve 'amlogic,boot-pages' property: %d",
>> + ret);
>> + goto err_chip_buf_free;
>> + }
>> +
>> + ret = ofnode_read_u32(node, "amlogic,boot-page-step",
>> + &meson_chip->boot_page_step);
>> + if (ret) {
>> + dev_err(dev, "could not retrieve 'amlogic,boot-page-step' property: %d",
>> + ret);
>> + goto err_chip_buf_free;
>> + }
>> + }
>> +
>> ret = nand_register(0, mtd);
>> if (ret) {
>> dev_err(dev, "'nand_register()' failed: %d\n", ret);
>> --
>> 2.30.1
>>
>
>
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