mtd: rawnand: meson: read/write access for boot ROM pages

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@salutedevices.com>
Reviewed-by: Michael Trimarchi <michael@amarulasolutions.com>
Link: https://lore.kernel.org/r/20240826131710.29746-4-avkrasnov@salutedevices.com
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>

diff --git a/drivers/mtd/nand/raw/meson_nand.c b/drivers/mtd/nand/raw/meson_nand.c
index 2d77ee51ce5b0e9fa85beed92cd48b0f0800af33..28c851f103b63b6eeb967e415404f28c8baeeb90 100644 (file)
--- a/drivers/mtd/nand/raw/meson_nand.c
+++ b/drivers/mtd/nand/raw/meson_nand.c
@@ -39,6 +39,7 @@
 #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))
@@ -77,6 +78,8 @@
 
 #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)
@@ -140,6 +143,8 @@
 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;
@@ -228,33 +233,46 @@ 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;
        unsigned int scrambler;
+       u32 cmd;
 
        if (nand->options & NAND_NEED_SCRAMBLING)
                scrambler = NFC_CMD_SCRAMBLER_ENABLE;
        else
                scrambler = NFC_CMD_SCRAMBLER_DISABLE;
 
-       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)) {
+               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);
@@ -1131,6 +1149,24 @@ 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);