Merge tag 'mtd/for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux

Pull MTD updates from Miquel Raynal:
 "MTD core:
   - drop inactive maintainers, update the repositories and add IRC
     channel
   - debugfs functions improvements
   - initialize more structure parameters
   - misc fixes reported by robots

  MTD devices:
   - spear_smi: Fixed Write Burst mode
   - new Intel IXP4xx flash probing hook

  Raw NAND core:
   - useless extra checks dropped
   - update the detection of the bad block markers position

  Raw NAND controller drivers:
   - Cadence: new driver
   - Brcmnand: support for flash-dma v0 + fixes
   - Denali: drop support for the legacy controller/chip DT representation
   - superfluous dev_err() calls removed

  SPI NOR core changes:
   - introduce 'struct spi_nor_controller_ops'
   - clean the Register Operations methods
   - use dev_dbg insted of dev_err for low level info
   - fix retlen handling in sst_write()
   - fix silent truncations in spi_nor_read and spi_nor_read_raw()
   - fix the clearing of QE bit on lock()/unlock()
   - rework the disabling of the block write protection
   - rework the Quad Enable methods
   - make sure nor->spimem and nor->controller_ops are mutually exclusive
   - set default Quad Enable method for ISSI flashes
   - add support for few flashes

  SPI NOR controller drivers changes:
   - intel-spi:
      - support chips without software sequencer
      - add support for Intel Cannon Lake and Intel Comet Lake-H flashes

  CFI core changes:
   - code cleanups related useless initializers and coding style issues
   - fix for a possible double free problem in cfi_cmdset_0002
   - improved HyperFlash error reporting and handling in cfi_cmdset_0002 core"

* tag 'mtd/for-5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux: (73 commits)
  mtd: devices: fix mchp23k256 read and write
  mtd: no need to check return value of debugfs_create functions
  mtd: spi-nor: Set default Quad Enable method for ISSI flashes
  mtd: spi-nor: Add support for is25wp256
  mtd: spi-nor: Add support for w25q256jw
  mtd: spi-nor: Move condition to avoid a NULL check
  mtd: spi-nor: Make sure nor->spimem and nor->controller_ops are mutually exclusive
  mtd: spi-nor: Rename Quad Enable methods
  mtd: spi-nor: Merge spansion Quad Enable methods
  mtd: spi-nor: Rename CR_QUAD_EN_SPAN to SR2_QUAD_EN_BIT1
  mtd: spi-nor: Extend the SR Read Back test
  mtd: spi-nor: Rework the disabling of block write protection
  mtd: spi-nor: Fix clearing of QE bit on lock()/unlock()
  mtd: cfi_cmdset_0002: fix delayed error detection on HyperFlash
  mtd: cfi_cmdset_0002: only check errors when ready in cfi_check_err_status()
  mtd: cfi_cmdset_0002: don't free cfi->cfiq in error path of cfi_amdstd_setup()
  mtd: cfi_cmdset_*: kill useless 'ret' variable initializers
  mtd: cfi_util: use DIV_ROUND_UP() in cfi_udelay()
  mtd: spi-nor: Print debug message when the read back test fails
  mtd: spi-nor: Check all the bits written, not just the BP ones
  ...

48 files changed, 4525 insertions, 1023 deletions

diff --git a/Documentation/devicetree/bindings/mtd/cadence-nand-controller.txt b/Documentation/devicetree/bindings/mtd/cadence-nand-controller.txt
new file mode 100644
index 000000000000..f3893c4d3c6a
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/cadence-nand-controller.txt
@@ -0,0 +1,53 @@
+* Cadence NAND controller
+
+Required properties:
+  - compatible : "cdns,hp-nfc"
+  - reg : Contains two entries, each of which is a tuple consisting of a
+	  physical address and length. The first entry is the address and
+	  length of the controller register set. The second entry is the
+	  address and length of the Slave DMA data port.
+  - reg-names: should contain "reg" and "sdma"
+  - #address-cells: should be 1. The cell encodes the chip select connection.
+  - #size-cells : should be 0.
+  - interrupts : The interrupt number.
+  - clocks: phandle of the controller core clock (nf_clk).
+
+Optional properties:
+  - dmas: shall reference DMA channel associated to the NAND controller
+  - cdns,board-delay-ps : Estimated Board delay. The value includes the total
+    round trip delay for the signals and is used for deciding on values
+    associated with data read capture. The example formula for SDR mode is
+    the following:
+    board delay = RE#PAD delay + PCB trace to device + PCB trace from device
+    + DQ PAD delay
+
+Child nodes represent the available NAND chips.
+
+Required properties of NAND chips:
+  - reg: shall contain the native Chip Select ids from 0 to max supported by
+    the cadence nand flash controller
+
+See Documentation/devicetree/bindings/mtd/nand.txt for more details on
+generic bindings.
+
+Example:
+
+nand_controller: nand-controller@60000000 {
+	  compatible = "cdns,hp-nfc";
+	  #address-cells = <1>;
+	  #size-cells = <0>;
+	  reg = <0x60000000 0x10000>, <0x80000000 0x10000>;
+	  reg-names = "reg", "sdma";
+	  clocks = <&nf_clk>;
+	  cdns,board-delay-ps = <4830>;
+	  interrupts = <2 0>;
+	  nand@0 {
+	      reg = <0>;
+	      label = "nand-1";
+	  };
+	  nand@1 {
+	      reg = <1>;
+	      label = "nand-2";
+	  };
+
+};
diff --git a/Documentation/devicetree/bindings/mtd/intel,ixp4xx-flash.txt b/Documentation/devicetree/bindings/mtd/intel,ixp4xx-flash.txt
new file mode 100644
index 000000000000..4bdcb92ae381
--- /dev/null
+++ b/Documentation/devicetree/bindings/mtd/intel,ixp4xx-flash.txt
@@ -0,0 +1,22 @@
+Flash device on Intel IXP4xx SoC
+
+This flash is regular CFI compatible (Intel or AMD extended) flash chips with
+specific big-endian or mixed-endian memory access pattern.
+
+Required properties:
+- compatible : must be "intel,ixp4xx-flash", "cfi-flash";
+- reg : memory address for the flash chip
+- bank-width : width in bytes of flash interface, should be <2>
+
+For the rest of the properties, see mtd-physmap.txt.
+
+The device tree may optionally contain sub-nodes describing partitions of the
+address space. See partition.txt for more detail.
+
+Example:
+
+flash@50000000 {
+	compatible = "intel,ixp4xx-flash", "cfi-flash";
+	reg = <0x50000000 0x01000000>;
+	bank-width = <2>;
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index bf8daba4afbb..598749df53e2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3595,6 +3595,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/media/cdns,*.txt
 F:	drivers/media/platform/cadence/cdns-csi2*
 
+CADENCE NAND DRIVER
+M:	Piotr Sroka <piotrs@cadence.com>
+L:	linux-mtd@lists.infradead.org
+S:	Maintained
+F:	drivers/mtd/nand/raw/cadence-nand-controller.c
+F:	Documentation/devicetree/bindings/mtd/cadence-nand-controller.txt
+
 CADET FM/AM RADIO RECEIVER DRIVER
 M:	Hans Verkuil <hverkuil@xs4all.nl>
 L:	linux-media@vger.kernel.org
@@ -10537,15 +10544,13 @@ F:	include/linux/vmalloc.h
 F:	mm/
 
 MEMORY TECHNOLOGY DEVICES (MTD)
-M:	David Woodhouse <dwmw2@infradead.org>
-M:	Brian Norris <computersforpeace@gmail.com>
-M:	Marek Vasut <marek.vasut@gmail.com>
 M:	Miquel Raynal <miquel.raynal@bootlin.com>
 M:	Richard Weinberger <richard@nod.at>
 M:	Vignesh Raghavendra <vigneshr@ti.com>
 L:	linux-mtd@lists.infradead.org
 W:	http://www.linux-mtd.infradead.org/
 Q:	http://patchwork.ozlabs.org/project/linux-mtd/list/
+C:	irc://irc.oftc.net/mtd
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/fixes
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next
 S:	Maintained
@@ -15296,7 +15301,6 @@ F:	arch/arm/boot/dts/spear*
 F:	arch/arm/mach-spear/
 
 SPI NOR SUBSYSTEM
-M:	Marek Vasut <marek.vasut@gmail.com>
 M:	Tudor Ambarus <tudor.ambarus@microchip.com>
 L:	linux-mtd@lists.infradead.org
 W:	http://www.linux-mtd.infradead.org/
@@ -16593,10 +16597,9 @@ F:	drivers/media/pci/tw686x/
 
 UBI FILE SYSTEM (UBIFS)
 M:	Richard Weinberger <richard@nod.at>
-M:	Artem Bityutskiy <dedekind1@gmail.com>
-M:	Adrian Hunter <adrian.hunter@intel.com>
 L:	linux-mtd@lists.infradead.org
-T:	git git://git.infradead.org/ubifs-2.6.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git next
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git fixes
 W:	http://www.linux-mtd.infradead.org/doc/ubifs.html
 S:	Supported
 F:	Documentation/filesystems/ubifs.txt
@@ -16711,11 +16714,11 @@ S:	Maintained
 F:	drivers/scsi/ufs/ufs-mediatek*
 
 UNSORTED BLOCK IMAGES (UBI)
-M:	Artem Bityutskiy <dedekind1@gmail.com>
 M:	Richard Weinberger <richard@nod.at>
 W:	http://www.linux-mtd.infradead.org/
 L:	linux-mtd@lists.infradead.org
-T:	git git://git.infradead.org/ubifs-2.6.git
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git next
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs.git fixes
 S:	Supported
 F:	drivers/mtd/ubi/
 F:	include/linux/mtd/ubi.h
diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index 79a53cb8507b..00a79489067c 100644
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -1353,7 +1353,7 @@ static int do_point_onechip (struct map_info *map, struct flchip *chip, loff_t a
 {
 	unsigned long cmd_addr;
 	struct cfi_private *cfi = map->fldrv_priv;
-	int ret = 0;
+	int ret;
 
 	adr += chip->start;
 
@@ -1383,7 +1383,7 @@ static int cfi_intelext_point(struct mtd_info *mtd, loff_t from, size_t len,
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long ofs, last_end = 0;
 	int chipnum;
-	int ret = 0;
+	int ret;
 
 	if (!map->virt)
 		return -EINVAL;
@@ -1550,7 +1550,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status, write_cmd;
-	int ret=0;
+	int ret;
 
 	adr += chip->start;
 
@@ -1624,7 +1624,7 @@ static int cfi_intelext_write_words (struct mtd_info *mtd, loff_t to , size_t le
 {
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
-	int ret = 0;
+	int ret;
 	int chipnum;
 	unsigned long ofs;
 
@@ -1871,7 +1871,7 @@ static int cfi_intelext_writev (struct mtd_info *mtd, const struct kvec *vecs,
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	int wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
-	int ret = 0;
+	int ret;
 	int chipnum;
 	unsigned long ofs, vec_seek, i;
 	size_t len = 0;
diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
index cf8c8be40a9c..04b383bc3947 100644
--- a/drivers/mtd/chips/cfi_cmdset_0002.c
+++ b/drivers/mtd/chips/cfi_cmdset_0002.c
@@ -123,19 +123,23 @@ static int cfi_use_status_reg(struct cfi_private *cfi)
 		(extp->SoftwareFeatures & poll_mask) == CFI_POLL_STATUS_REG;
 }
 
-static void cfi_check_err_status(struct map_info *map, struct flchip *chip,
-				 unsigned long adr)
+static int cfi_check_err_status(struct map_info *map, struct flchip *chip,
+				unsigned long adr)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
 	map_word status;
 
 	if (!cfi_use_status_reg(cfi))
-		return;
+		return 0;
 
 	cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 			 cfi->device_type, NULL);
 	status = map_read(map, adr);
 
+	/* The error bits are invalid while the chip's busy */
+	if (!map_word_bitsset(map, status, CMD(CFI_SR_DRB)))
+		return 0;
+
 	if (map_word_bitsset(map, status, CMD(0x3a))) {
 		unsigned long chipstatus = MERGESTATUS(status);
 
@@ -151,7 +155,12 @@ static void cfi_check_err_status(struct map_info *map, struct flchip *chip,
 		if (chipstatus & CFI_SR_SLSB)
 			pr_err("%s sector write protected, status %lx\n",
 			       map->name, chipstatus);
+
+		/* Erase/Program status bits are set on the operation failure */
+		if (chipstatus & (CFI_SR_ESB | CFI_SR_PSB))
+			return 1;
 	}
+	return 0;
 }
 
 /* #define DEBUG_CFI_FEATURES */
@@ -785,7 +794,6 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd)
 	kfree(mtd->eraseregions);
 	kfree(mtd);
 	kfree(cfi->cmdset_priv);
-	kfree(cfi->cfiq);
 	return NULL;
 }
 
@@ -848,20 +856,16 @@ static int __xipram chip_good(struct map_info *map, struct flchip *chip,
 
 	if (cfi_use_status_reg(cfi)) {
 		map_word ready = CMD(CFI_SR_DRB);
-		map_word err = CMD(CFI_SR_PSB | CFI_SR_ESB);
+
 		/*
 		 * For chips that support status register, check device
-		 * ready bit and Erase/Program status bit to know if
-		 * operation succeeded.
+		 * ready bit
 		 */
 		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
 				 cfi->device_type, NULL);
 		curd = map_read(map, addr);
 
-		if (map_word_andequal(map, curd, ready, ready))
-			return !map_word_bitsset(map, curd, err);
-
-		return 0;
+		return map_word_andequal(map, curd, ready, ready);
 	}
 
 	oldd = map_read(map, addr);
@@ -1699,8 +1703,11 @@ static int __xipram do_write_oneword_once(struct map_info *map,
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum))
+		if (chip_good(map, chip, adr, datum)) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		/* Latency issues. Drop the lock, wait a while and retry */
 		UDELAY(map, chip, adr, 1);
@@ -1713,7 +1720,7 @@ static int __xipram do_write_oneword_start(struct map_info *map,
 					   struct flchip *chip,
 					   unsigned long adr, int mode)
 {
-	int ret = 0;
+	int ret;
 
 	mutex_lock(&chip->mutex);
 
@@ -1773,7 +1780,6 @@ static int __xipram do_write_oneword_retry(struct map_info *map,
 	ret = do_write_oneword_once(map, chip, adr, datum, mode, cfi);
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -1791,7 +1797,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
 				     unsigned long adr, map_word datum,
 				     int mode)
 {
-	int ret = 0;
+	int ret;
 
 	adr += chip->start;
 
@@ -1815,7 +1821,7 @@ static int cfi_amdstd_write_words(struct mtd_info *mtd, loff_t to, size_t len,
 {
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
-	int ret = 0;
+	int ret;
 	int chipnum;
 	unsigned long ofs, chipstart;
 	DECLARE_WAITQUEUE(wait, current);
@@ -1970,12 +1976,17 @@ static int __xipram do_write_buffer_wait(struct map_info *map,
 		 */
 		if (time_after(jiffies, timeo) &&
 		    !chip_good(map, chip, adr, datum)) {
+			pr_err("MTD %s(): software timeout, address:0x%.8lx.\n",
+			       __func__, adr);
 			ret = -EIO;
 			break;
 		}
 
-		if (chip_good(map, chip, adr, datum))
+		if (chip_good(map, chip, adr, datum)) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		/* Latency issues. Drop the lock, wait a while and retry */
 		UDELAY(map, chip, adr, 1);
@@ -2014,7 +2025,7 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 				    int len)
 {
 	struct cfi_private *cfi = map->fldrv_priv;
-	int ret = -EIO;
+	int ret;
 	unsigned long cmd_adr;
 	int z, words;
 	map_word datum;
@@ -2071,12 +2082,8 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
 				chip->word_write_time);
 
 	ret = do_write_buffer_wait(map, chip, adr, datum);
-	if (ret) {
-		cfi_check_err_status(map, chip, adr);
+	if (ret)
 		do_write_buffer_reset(map, chip, cfi);
-		pr_err("MTD %s(): software timeout, address:0x%.8lx.\n",
-		       __func__, adr);
-	}
 
 	xip_enable(map, chip, adr);
 
@@ -2095,7 +2102,7 @@ static int cfi_amdstd_write_buffers(struct mtd_info *mtd, loff_t to, size_t len,
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	int wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
-	int ret = 0;
+	int ret;
 	int chipnum;
 	unsigned long ofs;
 
@@ -2232,7 +2239,7 @@ static int do_panic_write_oneword(struct map_info *map, struct flchip *chip,
 	struct cfi_private *cfi = map->fldrv_priv;
 	int retry_cnt = 0;
 	map_word oldd;
-	int ret = 0;
+	int ret;
 	int i;
 
 	adr += chip->start;
@@ -2271,9 +2278,9 @@ retry:
 		udelay(1);
 	}
 
-	if (!chip_good(map, chip, adr, datum)) {
+	if (!chip_good(map, chip, adr, datum) ||
+	    cfi_check_err_status(map, chip, adr)) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -2307,7 +2314,7 @@ static int cfi_amdstd_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long ofs, chipstart;
-	int ret = 0;
+	int ret;
 	int chipnum;
 
 	chipnum = to >> cfi->chipshift;
@@ -2411,7 +2418,7 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip)
 	unsigned long timeo = jiffies + HZ;
 	unsigned long int adr;
 	DECLARE_WAITQUEUE(wait, current);
-	int ret = 0;
+	int ret;
 	int retry_cnt = 0;
 
 	adr = cfi->addr_unlock1;
@@ -2467,8 +2474,11 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip)
 			chip->erase_suspended = 0;
 		}
 
-		if (chip_good(map, chip, adr, map_word_ff(map)))
+		if (chip_good(map, chip, adr, map_word_ff(map))) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		if (time_after(jiffies, timeo)) {
 			printk(KERN_WARNING "MTD %s(): software timeout\n",
@@ -2483,7 +2493,6 @@ static int __xipram do_erase_chip(struct map_info *map, struct flchip *chip)
 	/* Did we succeed? */
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
@@ -2508,7 +2517,7 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long timeo = jiffies + HZ;
 	DECLARE_WAITQUEUE(wait, current);
-	int ret = 0;
+	int ret;
 	int retry_cnt = 0;
 
 	adr += chip->start;
@@ -2564,8 +2573,11 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 			chip->erase_suspended = 0;
 		}
 
-		if (chip_good(map, chip, adr, map_word_ff(map)))
+		if (chip_good(map, chip, adr, map_word_ff(map))) {
+			if (cfi_check_err_status(map, chip, adr))
+				ret = -EIO;
 			break;
+		}
 
 		if (time_after(jiffies, timeo)) {
 			printk(KERN_WARNING "MTD %s(): software timeout\n",
@@ -2580,7 +2592,6 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
 	/* Did we succeed? */
 	if (ret) {
 		/* reset on all failures. */
-		cfi_check_err_status(map, chip, adr);
 		map_write(map, CMD(0xF0), chip->start);
 		/* FIXME - should have reset delay before continuing */
 
diff --git a/drivers/mtd/chips/cfi_cmdset_0020.c b/drivers/mtd/chips/cfi_cmdset_0020.c
index e752067526a5..54edae63b92d 100644
--- a/drivers/mtd/chips/cfi_cmdset_0020.c
+++ b/drivers/mtd/chips/cfi_cmdset_0020.c
@@ -611,7 +611,7 @@ static int cfi_staa_write_buffers (struct mtd_info *mtd, loff_t to,
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	int wbufsize = cfi_interleave(cfi) << cfi->cfiq->MaxBufWriteSize;
-	int ret = 0;
+	int ret;
 	int chipnum;
 	unsigned long ofs;
 
@@ -895,7 +895,7 @@ static int cfi_staa_erase_varsize(struct mtd_info *mtd,
 {	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long adr, len;
-	int chipnum, ret = 0;
+	int chipnum, ret;
 	int i, first;
 	struct mtd_erase_region_info *regions = mtd->eraseregions;
 
@@ -1132,7 +1132,7 @@ static int cfi_staa_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long adr;
-	int chipnum, ret = 0;
+	int chipnum, ret;
 #ifdef DEBUG_LOCK_BITS
 	int ofs_factor = cfi->interleave * cfi->device_type;
 #endif
@@ -1279,7 +1279,7 @@ static int cfi_staa_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	struct map_info *map = mtd->priv;
 	struct cfi_private *cfi = map->fldrv_priv;
 	unsigned long adr;
-	int chipnum, ret = 0;
+	int chipnum, ret;
 #ifdef DEBUG_LOCK_BITS
 	int ofs_factor = cfi->interleave * cfi->device_type;
 #endif
diff --git a/drivers/mtd/chips/cfi_util.c b/drivers/mtd/chips/cfi_util.c
index e3b266ee06af..e2d4db05aeb3 100644
--- a/drivers/mtd/chips/cfi_util.c
+++ b/drivers/mtd/chips/cfi_util.c
@@ -26,7 +26,7 @@
 void cfi_udelay(int us)
 {
 	if (us >= 1000) {
-		msleep((us+999)/1000);
+		msleep(DIV_ROUND_UP(us, 1000));
 	} else {
 		udelay(us);
 		cond_resched();
diff --git a/drivers/mtd/devices/mchp23k256.c b/drivers/mtd/devices/mchp23k256.c
index b20d02b4f830..77c872fd3d83 100644
--- a/drivers/mtd/devices/mchp23k256.c
+++ b/drivers/mtd/devices/mchp23k256.c
@@ -64,15 +64,17 @@ static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
 	struct spi_transfer transfer[2] = {};
 	struct spi_message message;
 	unsigned char command[MAX_CMD_SIZE];
-	int ret;
+	int ret, cmd_len;
 
 	spi_message_init(&message);
 
+	cmd_len = mchp23k256_cmdsz(flash);
+
 	command[0] = MCHP23K256_CMD_WRITE;
 	mchp23k256_addr2cmd(flash, to, command);
 
 	transfer[0].tx_buf = command;
-	transfer[0].len = mchp23k256_cmdsz(flash);
+	transfer[0].len = cmd_len;
 	spi_message_add_tail(&transfer[0], &message);
 
 	transfer[1].tx_buf = buf;
@@ -88,8 +90,8 @@ static int mchp23k256_write(struct mtd_info *mtd, loff_t to, size_t len,
 	if (ret)
 		return ret;
 
-	if (retlen && message.actual_length > sizeof(command))
-		*retlen += message.actual_length - sizeof(command);
+	if (retlen && message.actual_length > cmd_len)
+		*retlen += message.actual_length - cmd_len;
 
 	return 0;
 }
@@ -101,16 +103,18 @@ static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
 	struct spi_transfer transfer[2] = {};
 	struct spi_message message;
 	unsigned char command[MAX_CMD_SIZE];
-	int ret;
+	int ret, cmd_len;
 
 	spi_message_init(&message);
 
+	cmd_len = mchp23k256_cmdsz(flash);
+
 	memset(&transfer, 0, sizeof(transfer));
 	command[0] = MCHP23K256_CMD_READ;
 	mchp23k256_addr2cmd(flash, from, command);
 
 	transfer[0].tx_buf = command;
-	transfer[0].len = mchp23k256_cmdsz(flash);
+	transfer[0].len = cmd_len;
 	spi_message_add_tail(&transfer[0], &message);
 
 	transfer[1].rx_buf = buf;
@@ -126,8 +130,8 @@ static int mchp23k256_read(struct mtd_info *mtd, loff_t from, size_t len,
 	if (ret)
 		return ret;
 
-	if (retlen && message.actual_length > sizeof(command))
-		*retlen += message.actual_length - sizeof(command);
+	if (retlen && message.actual_length > cmd_len)
+		*retlen += message.actual_length - cmd_len;
 
 	return 0;
 }
diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
index 986f81d2f93e..79dcca16481d 100644
--- a/drivers/mtd/devices/spear_smi.c
+++ b/drivers/mtd/devices/spear_smi.c
@@ -592,6 +592,26 @@ static int spear_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
 	return 0;
 }
 
+/*
+ * The purpose of this function is to ensure a memcpy_toio() with byte writes
+ * only. Its structure is inspired from the ARM implementation of _memcpy_toio()
+ * which also does single byte writes but cannot be used here as this is just an
+ * implementation detail and not part of the API. Not mentioning the comment
+ * stating that _memcpy_toio() should be optimized.
+ */
+static void spear_smi_memcpy_toio_b(volatile void __iomem *dest,
+				    const void *src, size_t len)
+{
+	const unsigned char *from = src;
+
+	while (len) {
+		len--;
+		writeb(*from, dest);
+		from++;
+		dest++;
+	}
+}
+
 static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
 		void __iomem *dest, const void *src, size_t len)
 {
@@ -614,7 +634,23 @@ static inline int spear_smi_cpy_toio(struct spear_smi *dev, u32 bank,
 	ctrlreg1 = readl(dev->io_base + SMI_CR1);
 	writel((ctrlreg1 | WB_MODE) & ~SW_MODE, dev->io_base + SMI_CR1);
 
-	memcpy_toio(dest, src, len);
+	/*
+	 * In Write Burst mode (WB_MODE), the specs states that writes must be:
+	 * - incremental
+	 * - of the same size
+	 * The ARM implementation of memcpy_toio() will optimize the number of
+	 * I/O by using as much 4-byte writes as possible, surrounded by
+	 * 2-byte/1-byte acc