Merge tag 'mtd/for-4.16' of git://git.infradead.org/linux-mtd

Pull MTD updates from Boris Brezillon:
 "MTD core changes:
   - Rework core functions to avoid duplicating generic checks in
     NAND/OneNAND sub-layers
   - Update the MAINTAINERS entry to reflect the fact that MTD
     maintainers now use a single git tree

  MTD driver changes:
   - CFI: use macros instead of inline functions to limit stack usage
     and make KASAN happy

  NAND core changes:
   - Fix NAND_CMD_NONE handling in nand_command[_lp]() hooks
   - Introduce the ->exec_op() infrastructure
   - Rework NAND buffers handling
   - Fix ECC requirements for K9F4G08U0D
   - Fix nand_do_read_oob() to return the number of bitflips
   - Mark K9F1G08U0E as not supporting subpage writes

  NAND driver changes:
   - MTK: Rework the driver to support new IP versions
   - OMAP OneNAND: Full rework to use new APIs (libgpio, dmaengine) and
     fix DT support
   - Marvell: Add a new driver to replace the pxa3xx one

  SPI NOR core changes:
   - Add support to new ISSI and Cypress/Spansion memory parts.
   - Fix support of Micron memories by checking error bits in the FSR.
   - Fix update of block-protection bits by reading back the SR.
   - Restore the internal state of the SPI flash memory when removing
     the device.

  SPI NOR driver changes:
   - Maintenance for Freescale, Intel and Metiatek drivers.
   - Add support of the direct access mode for the Cadence QSPI
     controller"

* tag 'mtd/for-4.16' of git://git.infradead.org/linux-mtd: (93 commits)
  mtd: nand: sunxi: Fix ECC strength choice
  mtd: nand: gpmi: Fix subpage reads
  mtd: nand: Fix build issues due to an anonymous union
  mtd: nand: marvell: Fix missing memory allocation modifier
  mtd: nand: marvell: remove redundant variable 'oob_len'
  mtd: nand: marvell: fix spelling mistake: "suceed"-> "succeed"
  mtd: onenand: omap2: Remove redundant dev_err call in omap2_onenand_probe()
  mtd: Remove duplicate checks on mtd_oob_ops parameter
  mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing
  mtd: mtdpart: Make ECC stat handling consistent
  mtd: onenand: omap2: print resource using %pR format string
  mtd: mtk-nor: modify functions' name more generally
  mtd: onenand: samsung: remove incorrect __iomem annotation
  MAINTAINERS: Add entry for Marvell NAND controller driver
  ARM: OMAP2+: Remove gpmc-onenand
  mtd: onenand: omap2: Configure driver from DT
  mtd: onenand: omap2: Decouple DMA enabling from INT pin availability
  mtd: onenand: omap2: Do not make delay for GPIO OMAP3 specific
  mtd: onenand: omap2: Convert to use dmaengine for memcpy
  mtd: onenand: omap2: Unify OMAP2 and OMAP3 DMA implementation
  ...

1 files changed, 34 insertions, 2 deletions

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 73b605577447..28553c840d32 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -503,6 +503,11 @@ int add_mtd_device(struct mtd_info *mtd)
 		return -EEXIST;
 
 	BUG_ON(mtd->writesize == 0);
+
+	if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
+		    !(mtd->flags & MTD_NO_ERASE)))
+		return -EINVAL;
+
 	mutex_lock(&mtd_table_mutex);
 
 	i = idr_alloc(&mtd_idr, mtd, 0, 0, GFP_KERNEL);
@@ -1053,7 +1058,20 @@ int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	 * representing the maximum number of bitflips that were corrected on
 	 * any one ecc region (if applicable; zero otherwise).
 	 */
-	ret_code = mtd->_read(mtd, from, len, retlen, buf);
+	if (mtd->_read) {
+		ret_code = mtd->_read(mtd, from, len, retlen, buf);
+	} else if (mtd->_read_oob) {
+		struct mtd_oob_ops ops = {
+			.len = len,
+			.datbuf = buf,
+		};
+
+		ret_code = mtd->_read_oob(mtd, from, &ops);
+		*retlen = ops.retlen;
+	} else {
+		return -ENOTSUPP;
+	}
+
 	if (unlikely(ret_code < 0))
 		return ret_code;
 	if (mtd->ecc_strength == 0)
@@ -1068,11 +1086,25 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 	*retlen = 0;
 	if (to < 0 || to >= mtd->size || len > mtd->size - to)
 		return -EINVAL;
-	if (!mtd->_write || !(mtd->flags & MTD_WRITEABLE))
+	if ((!mtd->_write && !mtd->_write_oob) ||
+	    !(mtd->flags & MTD_WRITEABLE))
 		return -EROFS;
 	if (!len)
 		return 0;
 	ledtrig_mtd_activity();
+
+	if (!mtd->_write) {
+		struct mtd_oob_ops ops = {
+			.len = len,
+			.datbuf = (u8 *)buf,
+		};
+		int ret;
+
+		ret = mtd->_write_oob(mtd, to, &ops);
+		*retlen = ops.retlen;
+		return ret;
+	}
+
 	return mtd->_write(mtd, to, len, retlen, buf);
 }
 EXPORT_SYMBOL_GPL(mtd_write);