This adds support for OTP area access on MX30LFxG18AC chip series.

Signed-off-by: Arseniy Krasnov <avkras...@sberdevices.ru>
---
  v1 -> v2:
  * Add slab.h include due to kernel test robot error.
  v2 -> v3:
  * Use 'uint64_t' as input argument for 'do_div()' instead
    of 'unsigned long' due to kernel test robot error.
  v3 -> v4:
  * Use 'dev_err()' instead of 'WARN()'.
  * Call 'match_string()' before checking 'supports_set_get_features'
    in 'macronix_nand_setup_otp().
  * Use 'u8' instead of 'uint8_t' as ./checkpatch.pl wants.

 drivers/mtd/nand/raw/nand_macronix.c | 216 +++++++++++++++++++++++++++
 1 file changed, 216 insertions(+)

diff --git a/drivers/mtd/nand/raw/nand_macronix.c 
b/drivers/mtd/nand/raw/nand_macronix.c
index 1472f925f386..be1ffa93bebb 100644
--- a/drivers/mtd/nand/raw/nand_macronix.c
+++ b/drivers/mtd/nand/raw/nand_macronix.c
@@ -6,6 +6,7 @@
  * Author: Boris Brezillon <boris.brezil...@free-electrons.com>
  */
 
+#include <linux/slab.h>
 #include "linux/delay.h"
 #include "internals.h"
 
@@ -31,6 +32,20 @@
 
 #define MXIC_CMD_POWER_DOWN 0xB9
 
+#define ONFI_FEATURE_ADDR_30LFXG18AC_OTP       0x90
+#define MACRONIX_30LFXG18AC_OTP_START_PAGE     0
+#define MACRONIX_30LFXG18AC_OTP_PAGES          30
+#define MACRONIX_30LFXG18AC_OTP_PAGE_SIZE      2112
+#define MACRONIX_30LFXG18AC_OTP_START_BYTE     \
+       (MACRONIX_30LFXG18AC_OTP_START_PAGE *   \
+        MACRONIX_30LFXG18AC_OTP_PAGE_SIZE)
+#define MACRONIX_30LFXG18AC_OTP_SIZE_BYTES     \
+       (MACRONIX_30LFXG18AC_OTP_PAGES *        \
+        MACRONIX_30LFXG18AC_OTP_PAGE_SIZE)
+
+#define MACRONIX_30LFXG18AC_OTP_EN             BIT(0)
+#define MACRONIX_30LFXG18AC_OTP_LOCKED         BIT(1)
+
 struct nand_onfi_vendor_macronix {
        u8 reserved;
        u8 reliability_func;
@@ -316,6 +331,206 @@ static void macronix_nand_deep_power_down_support(struct 
nand_chip *chip)
        chip->ops.resume = mxic_nand_resume;
 }
 
+static int macronix_30lfxg18ac_get_otp_info(struct mtd_info *mtd, size_t len,
+                                           size_t *retlen,
+                                           struct otp_info *buf)
+{
+       if (len < sizeof(*buf))
+               return -EINVAL;
+
+       /* Don't know how to check that OTP is locked. */
+       buf->locked = 0;
+       buf->start = MACRONIX_30LFXG18AC_OTP_START_BYTE;
+       buf->length = MACRONIX_30LFXG18AC_OTP_SIZE_BYTES;
+
+       *retlen = sizeof(*buf);
+
+       return 0;
+}
+
+static int macronix_30lfxg18ac_otp_enable(struct nand_chip *nand)
+{
+       u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
+
+       feature_buf[0] = MACRONIX_30LFXG18AC_OTP_EN;
+       return nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
+                                feature_buf);
+}
+
+static int macronix_30lfxg18ac_otp_disable(struct nand_chip *nand)
+{
+       u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
+
+       return nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
+                                feature_buf);
+}
+
+static int __macronix_30lfxg18ac_rw_otp(struct mtd_info *mtd,
+                                       loff_t offs_in_flash,
+                                       size_t len, size_t *retlen,
+                                       u_char *buf, bool write)
+{
+       struct nand_chip *nand;
+       size_t bytes_handled;
+       off_t offs_in_page;
+       void *dma_buf;
+       u64 page;
+       int ret;
+
+       /* 'nand_prog/read_page_op()' may use 'buf' as DMA buffer,
+        * so allocate properly aligned memory for it. This is
+        * needed because cross page accesses may lead to unaligned
+        * buffer address for DMA.
+        */
+       dma_buf = kmalloc(MACRONIX_30LFXG18AC_OTP_PAGE_SIZE, GFP_KERNEL);
+       if (!dma_buf)
+               return -ENOMEM;
+
+       nand = mtd_to_nand(mtd);
+       nand_select_target(nand, 0);
+
+       ret = macronix_30lfxg18ac_otp_enable(nand);
+       if (ret)
+               goto out_otp;
+
+       page = offs_in_flash;
+       /* 'page' will be result of division. */
+       offs_in_page = do_div(page, MACRONIX_30LFXG18AC_OTP_PAGE_SIZE);
+       bytes_handled = 0;
+
+       while (bytes_handled < len &&
+              page < MACRONIX_30LFXG18AC_OTP_PAGES) {
+               size_t bytes_to_handle;
+
+               bytes_to_handle = min_t(size_t, len - bytes_handled,
+                                       MACRONIX_30LFXG18AC_OTP_PAGE_SIZE -
+                                       offs_in_page);
+
+               if (write) {
+                       memcpy(dma_buf, &buf[bytes_handled], bytes_to_handle);
+                       ret = nand_prog_page_op(nand, page, offs_in_page,
+                                               dma_buf, bytes_to_handle);
+               } else {
+                       ret = nand_read_page_op(nand, page, offs_in_page,
+                                               dma_buf, bytes_to_handle);
+                       if (!ret)
+                               memcpy(&buf[bytes_handled], dma_buf,
+                                      bytes_to_handle);
+               }
+               if (ret)
+                       goto out_otp;
+
+               bytes_handled += bytes_to_handle;
+               offs_in_page = 0;
+               page++;
+       }
+
+       *retlen = bytes_handled;
+
+out_otp:
+       if (ret)
+               dev_err(&mtd->dev, "failed to perform OTP IO: %i\n", ret);
+
+       ret = macronix_30lfxg18ac_otp_disable(nand);
+       if (ret)
+               dev_err(&mtd->dev, "failed to leave OTP mode after %s\n",
+                       write ? "write" : "read");
+
+       nand_deselect_target(nand);
+       kfree(dma_buf);
+
+       return ret;
+}
+
+static int macronix_30lfxg18ac_write_otp(struct mtd_info *mtd, loff_t to,
+                                        size_t len, size_t *rlen,
+                                        const u_char *buf)
+{
+       return __macronix_30lfxg18ac_rw_otp(mtd, to, len, rlen, (u_char *)buf,
+                                           true);
+}
+
+static int macronix_30lfxg18ac_read_otp(struct mtd_info *mtd, loff_t from,
+                                       size_t len, size_t *rlen,
+                                       u_char *buf)
+{
+       return __macronix_30lfxg18ac_rw_otp(mtd, from, len, rlen, buf, false);
+}
+
+static int macronix_30lfxg18ac_lock_otp(struct mtd_info *mtd, loff_t from,
+                                       size_t len)
+{
+       u8 feature_buf[ONFI_SUBFEATURE_PARAM_LEN] = { 0 };
+       struct nand_chip *nand;
+       int ret;
+
+       if (from != MACRONIX_30LFXG18AC_OTP_START_BYTE ||
+           len != MACRONIX_30LFXG18AC_OTP_SIZE_BYTES)
+               return -EINVAL;
+
+       dev_dbg(&mtd->dev, "locking OTP\n");
+
+       nand = mtd_to_nand(mtd);
+       nand_select_target(nand, 0);
+
+       feature_buf[0] = MACRONIX_30LFXG18AC_OTP_EN |
+                        MACRONIX_30LFXG18AC_OTP_LOCKED;
+       ret = nand_set_features(nand, ONFI_FEATURE_ADDR_30LFXG18AC_OTP,
+                               feature_buf);
+       if (ret) {
+               dev_err(&mtd->dev,
+                       "failed to lock OTP (set features): %i\n", ret);
+               nand_deselect_target(nand);
+               return ret;
+       }
+
+       /* Do dummy page prog with zero address. */
+       feature_buf[0] = 0;
+       ret = nand_prog_page_op(nand, 0, 0, feature_buf, 1);
+       if (ret)
+               dev_err(&mtd->dev,
+                       "failed to lock OTP (page prog): %i\n", ret);
+
+       ret = macronix_30lfxg18ac_otp_disable(nand);
+       if (ret)
+               dev_err(&mtd->dev, "failed to leave OTP mode after lock\n");
+
+       nand_deselect_target(nand);
+
+       return ret;
+}
+
+static void macronix_nand_setup_otp(struct nand_chip *chip)
+{
+       static const char * const supported_otp_models[] = {
+               "MX30LF1G18AC",
+               "MX30LF2G18AC",
+               "MX30LF4G18AC",
+       };
+       struct mtd_info *mtd;
+
+       if (match_string(supported_otp_models,
+                        ARRAY_SIZE(supported_otp_models),
+                        chip->parameters.model) < 0)
+               return;
+
+       if (!chip->parameters.supports_set_get_features)
+               return;
+
+       bitmap_set(chip->parameters.get_feature_list,
+                  ONFI_FEATURE_ADDR_30LFXG18AC_OTP, 1);
+       bitmap_set(chip->parameters.set_feature_list,
+                  ONFI_FEATURE_ADDR_30LFXG18AC_OTP, 1);
+
+       mtd = nand_to_mtd(chip);
+       mtd->_get_fact_prot_info = macronix_30lfxg18ac_get_otp_info;
+       mtd->_read_fact_prot_reg = macronix_30lfxg18ac_read_otp;
+       mtd->_get_user_prot_info = macronix_30lfxg18ac_get_otp_info;
+       mtd->_read_user_prot_reg = macronix_30lfxg18ac_read_otp;
+       mtd->_write_user_prot_reg = macronix_30lfxg18ac_write_otp;
+       mtd->_lock_user_prot_reg = macronix_30lfxg18ac_lock_otp;
+}
+
 static int macronix_nand_init(struct nand_chip *chip)
 {
        if (nand_is_slc(chip))
@@ -325,6 +540,7 @@ static int macronix_nand_init(struct nand_chip *chip)
        macronix_nand_onfi_init(chip);
        macronix_nand_block_protection_support(chip);
        macronix_nand_deep_power_down_support(chip);
+       macronix_nand_setup_otp(chip);
 
        return 0;
 }
-- 
2.35.0

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