Merge tag 'for-linus-20161008' of git://git.infradead.org/linux-mtd

Pull MTD updates from Brian Norris:
 "I've not been very active this cycle, so these are mostly from Boris,
  for the NAND flash subsystem.

  NAND:

   - Add the infrastructure to automate NAND timings configuration

   - Provide a generic DT property to maximize ECC strength

   - Some refactoring in the core bad block table handling, to help with
     improving some of the logic in error cases.

   - Minor cleanups and fixes

  MTD:

   - Add APIs for handling page pairing; this is necessary for reliably
     supporting MLC and TLC NAND flash, where paired-page disturbance
     affects reliability. Upper layers (e.g., UBI) should make use of
     these in the near future"

* tag 'for-linus-20161008' of git://git.infradead.org/linux-mtd: (35 commits)
  mtd: nand: fix trivial spelling error
  mtdpart: Propagate _get/put_device()
  mtd: nand: Provide nand_cleanup() function to free NAND related resources
  mtd: Kill the OF_MTD Kconfig option
  mtd: nand: mxc: Test CONFIG_OF instead of CONFIG_OF_MTD
  mtd: nand: Fix nand_command_lp() for 8bits opcodes
  mtd: nand: sunxi: Support ECC maximization
  mtd: nand: Support maximizing ECC when using software BCH
  mtd: nand: Add an option to maximize the ECC strength
  mtd: nand: mxc: Add timing setup for v2 controllers
  mtd: nand: mxc: implement onfi get/set features
  mtd: nand: sunxi: switch from manual to automated timing config
  mtd: nand: automate NAND timings selection
  mtd: nand: Expose data interface for ONFI mode 0
  mtd: nand: Add function to convert ONFI mode to data_interface
  mtd: nand: convert ONFI mode into data interface
  mtd: nand: Introduce nand_data_interface
  mtd: nand: Create a NAND reset function
  mtd: nand: remove unnecessary 'extern' from function declarations
  MAINTAINERS: Add maintainer entry for Ingenic JZ4780 NAND driver
  ...

Documentation/devicetree/bindings/mtd/nand.txt

@@ -35,6 +35,15 @@ Optional NAND chip properties:
 - nand-ecc-step-size: integer representing the number of data bytes
 		      that are covered by a single ECC step.
 
+- nand-ecc-maximize: boolean used to specify that you want to maximize ECC
+		     strength. The maximum ECC strength is both controller and
+		     chip dependent. The controller side has to select the ECC
+		     config providing the best strength and taking the OOB area
+		     size constraint into account.
+		     This is particularly useful when only the in-band area is
+		     used by the upper layers, and you want to make your NAND
+		     as reliable as possible.
+
 The ECC strength and ECC step size properties define the correction capability
 of a controller. Together, they say a controller can correct "{strength} bit
 errors per {size} bytes".

MAINTAINERS

@@ -6142,6 +6142,12 @@ M:	Zubair Lutfullah Kakakhel <Zubair.Kakakhel@imgtec.com>
 S:	Maintained
 F:	drivers/dma/dma-jz4780.c
 
+INGENIC JZ4780 NAND DRIVER
+M:	Harvey Hunt <harveyhuntnexus@gmail.com>
+L:	linux-mtd@lists.infradead.org
+S:	Maintained
+F:	drivers/mtd/nand/jz4780_*
+
 INTEGRITY MEASUREMENT ARCHITECTURE (IMA)
 M:	Mimi Zohar <zohar@linux.vnet.ibm.com>
 M:	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>

drivers/mtd/mtdcore.c

@@ -375,6 +375,110 @@ static int mtd_reboot_notifier(struct notifier_block *n, unsigned long state,
 	return NOTIFY_DONE;
 }
 
+/**
+ * mtd_wunit_to_pairing_info - get pairing information of a wunit
+ * @mtd: pointer to new MTD device info structure
+ * @wunit: write unit we are interested in
+ * @info: returned pairing information
+ *
+ * Retrieve pairing information associated to the wunit.
+ * This is mainly useful when dealing with MLC/TLC NANDs where pages can be
+ * paired together, and where programming a page may influence the page it is
+ * paired with.
+ * The notion of page is replaced by the term wunit (write-unit) to stay
+ * consistent with the ->writesize field.
+ *
+ * The @wunit argument can be extracted from an absolute offset using
+ * mtd_offset_to_wunit(). @info is filled with the pairing information attached
+ * to @wunit.
+ *
+ * From the pairing info the MTD user can find all the wunits paired with
+ * @wunit using the following loop:
+ *
+ * for (i = 0; i < mtd_pairing_groups(mtd); i++) {
+ *	info.pair = i;
+ *	mtd_pairing_info_to_wunit(mtd, &info);
+ *	...
+ * }
+ */
+int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
+			      struct mtd_pairing_info *info)
+{
+	int npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
+
+	if (wunit < 0 || wunit >= npairs)
+		return -EINVAL;
+
+	if (mtd->pairing && mtd->pairing->get_info)
+		return mtd->pairing->get_info(mtd, wunit, info);
+
+	info->group = 0;
+	info->pair = wunit;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtd_wunit_to_pairing_info);
+
+/**
+ * mtd_wunit_to_pairing_info - get wunit from pairing information
+ * @mtd: pointer to new MTD device info structure
+ * @info: pairing information struct
+ *
+ * Returns a positive number representing the wunit associated to the info
+ * struct, or a negative error code.
+ *
+ * This is the reverse of mtd_wunit_to_pairing_info(), and can help one to
+ * iterate over all wunits of a given pair (see mtd_wunit_to_pairing_info()
+ * doc).
+ *
+ * It can also be used to only program the first page of each pair (i.e.
+ * page attached to group 0), which allows one to use an MLC NAND in
+ * software-emulated SLC mode:
+ *
+ * info.group = 0;
+ * npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
+ * for (info.pair = 0; info.pair < npairs; info.pair++) {
+ *	wunit = mtd_pairing_info_to_wunit(mtd, &info);
+ *	mtd_write(mtd, mtd_wunit_to_offset(mtd, blkoffs, wunit),
+ *		  mtd->writesize, &retlen, buf + (i * mtd->writesize));
+ * }
+ */
+int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
+			      const struct mtd_pairing_info *info)
+{
+	int ngroups = mtd_pairing_groups(mtd);
+	int npairs = mtd_wunit_per_eb(mtd) / ngroups;
+
+	if (!info || info->pair < 0 || info->pair >= npairs ||
+	    info->group < 0 || info->group >= ngroups)
+		return -EINVAL;
+
+	if (mtd->pairing && mtd->pairing->get_wunit)
+		return mtd->pairing->get_wunit(mtd, info);
+
+	return info->pair;
+}
+EXPORT_SYMBOL_GPL(mtd_pairing_info_to_wunit);
+
+/**
+ * mtd_pairing_groups - get the number of pairing groups
+ * @mtd: pointer to new MTD device info structure
+ *
+ * Returns the number of pairing groups.
+ *
+ * This number is usually equal to the number of bits exposed by a single
+ * cell, and can be used in conjunction with mtd_pairing_info_to_wunit()
+ * to iterate over all pages of a given pair.
+ */
+int mtd_pairing_groups(struct mtd_info *mtd)
+{
+	if (!mtd->pairing || !mtd->pairing->ngroups)
+		return 1;
+
+	return mtd->pairing->ngroups;
+}
+EXPORT_SYMBOL_GPL(mtd_pairing_groups);
+
 /**
  *	add_mtd_device - register an MTD device
  *	@mtd: pointer to new MTD device info structure

drivers/mtd/mtdpart.c

@@ -317,6 +317,18 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
 	return res;
 }
 
+static int part_get_device(struct mtd_info *mtd)
+{
+	struct mtd_part *part = mtd_to_part(mtd);
+	return part->master->_get_device(part->master);
+}
+
+static void part_put_device(struct mtd_info *mtd)
+{
+	struct mtd_part *part = mtd_to_part(mtd);
+	part->master->_put_device(part->master);
+}
+
 static int part_ooblayout_ecc(struct mtd_info *mtd, int section,
 			      struct mtd_oob_region *oobregion)
 {
@@ -397,6 +409,7 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
 	slave->mtd.oobsize = master->oobsize;
 	slave->mtd.oobavail = master->oobavail;
 	slave->mtd.subpage_sft = master->subpage_sft;
+	slave->mtd.pairing = master->pairing;
 
 	slave->mtd.name = name;
 	slave->mtd.owner = master->owner;
@@ -463,6 +476,12 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
 		slave->mtd._block_isbad = part_block_isbad;
 	if (master->_block_markbad)
 		slave->mtd._block_markbad = part_block_markbad;
+
+	if (master->_get_device)
+		slave->mtd._get_device = part_get_device;
+	if (master->_put_device)
+		slave->mtd._put_device = part_put_device;
+
 	slave->mtd._erase = part_erase;
 	slave->master = master;
 	slave->offset = part->offset;

drivers/mtd/nand/Kconfig

@@ -88,11 +88,11 @@ config MTD_NAND_AMS_DELTA
 	  Support for NAND flash on Amstrad E3 (Delta).
 
 config MTD_NAND_OMAP2
-	tristate "NAND Flash device on OMAP2, OMAP3 and OMAP4"
-	depends on ARCH_OMAP2PLUS
+	tristate "NAND Flash device on OMAP2, OMAP3, OMAP4 and Keystone"
+	depends on (ARCH_OMAP2PLUS || ARCH_KEYSTONE)
 	help
-          Support for NAND flash on Texas Instruments OMAP2, OMAP3 and OMAP4
-	  platforms.
+          Support for NAND flash on Texas Instruments OMAP2, OMAP3, OMAP4
+	  and Keystone platforms.
 
 config MTD_NAND_OMAP_BCH
 	depends on MTD_NAND_OMAP2
@@ -428,7 +428,7 @@ config MTD_NAND_ORION
 
 config MTD_NAND_FSL_ELBC
 	tristate "NAND support for Freescale eLBC controllers"
-	depends on PPC
+	depends on FSL_SOC
 	select FSL_LBC
 	help
 	  Various Freescale chips, including the 8313, include a NAND Flash
@@ -438,7 +438,7 @@ config MTD_NAND_FSL_ELBC
 
 config MTD_NAND_FSL_IFC
 	tristate "NAND support for Freescale IFC controller"
-	depends on MTD_NAND && (FSL_SOC || ARCH_LAYERSCAPE)
+	depends on FSL_SOC || ARCH_LAYERSCAPE
 	select FSL_IFC
 	select MEMORY
 	help

drivers/mtd/nand/bf5xx_nand.c

@@ -761,8 +761,7 @@ static int bf5xx_nand_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, info);
 
-	spin_lock_init(&info->controller.lock);
-	init_waitqueue_head(&info->controller.wq);
+	nand_hw_control_init(&info->controller);
 
 	info->device     = &pdev->dev;
 	info->platform   = plat;

drivers/mtd/nand/brcmnand/brcmnand.c

@@ -1336,7 +1336,7 @@ static void brcmnand_cmdfunc(struct mtd_info *mtd, unsigned command,
 		u32 *flash_cache = (u32 *)ctrl->flash_cache;
 		int i;
 
-		brcmnand_soc_data_bus_prepare(ctrl->soc);
+		brcmnand_soc_data_bus_prepare(ctrl->soc, true);
 
 		/*
 		 * Must cache the FLASH_CACHE now, since changes in
@@ -1349,7 +1349,7 @@ static void brcmnand_cmdfunc(struct mtd_info *mtd, unsigned command,
 			 */
 			flash_cache[i] = be32_to_cpu(brcmnand_read_fc(ctrl, i));
 
-		brcmnand_soc_data_bus_unprepare(ctrl->soc);
+		brcmnand_soc_data_bus_unprepare(ctrl->soc, true);
 
 		/* Cleanup from HW quirk: restore SECTOR_SIZE_1K */
 		if (host->hwcfg.sector_size_1k)
@@ -1565,12 +1565,12 @@ static int brcmnand_read_by_pio(struct mtd_info *mtd, struct nand_chip *chip,
 		brcmnand_waitfunc(mtd, chip);
 
 		if (likely(buf)) {
-			brcmnand_soc_data_bus_prepare(ctrl->soc);
+			brcmnand_soc_data_bus_prepare(ctrl->soc, false);
 
 			for (j = 0; j < FC_WORDS; j++, buf++)
 				*buf = brcmnand_read_fc(ctrl, j);
 
-			brcmnand_soc_data_bus_unprepare(ctrl->soc);
+			brcmnand_soc_data_bus_unprepare(ctrl->soc, false);
 		}
 
 		if (oob)
@@ -1815,12 +1815,12 @@ static int brcmnand_write(struct mtd_info *mtd, struct nand_chip *chip,
 		(void)brcmnand_read_reg(ctrl, BRCMNAND_CMD_ADDRESS);
 
 		if (buf) {
-			brcmnand_soc_data_bus_prepare(ctrl->soc);
+			brcmnand_soc_data_bus_prepare(ctrl->soc, false);
 
 			for (j = 0; j < FC_WORDS; j++, buf++)
 				brcmnand_write_fc(ctrl, j, *buf);
 
-			brcmnand_soc_data_bus_unprepare(ctrl->soc);
+			brcmnand_soc_data_bus_unprepare(ctrl->soc, false);
 		} else if (oob) {
 			for (j = 0; j < FC_WORDS; j++)
 				brcmnand_write_fc(ctrl, j, 0xffffffff);
@@ -2370,8 +2370,7 @@ int brcmnand_probe(struct platform_device *pdev, struct brcmnand_soc *soc)
 
 	init_completion(&ctrl->done);
 	init_completion(&ctrl->dma_done);
-	spin_lock_init(&ctrl->controller.lock);
-	init_waitqueue_head(&ctrl->controller.wq);
+	nand_hw_control_init(&ctrl->controller);
 	INIT_LIST_HEAD(&ctrl->host_list);
 
 	/* NAND register range */

drivers/mtd/nand/brcmnand/brcmnand.h

@@ -23,19 +23,22 @@ struct dev_pm_ops;
 struct brcmnand_soc {
 	bool (*ctlrdy_ack)(struct brcmnand_soc *soc);
 	void (*ctlrdy_set_enabled)(struct brcmnand_soc *soc, bool en);
-	void (*prepare_data_bus)(struct brcmnand_soc *soc, bool prepare);
+	void (*prepare_data_bus)(struct brcmnand_soc *soc, bool prepare,
+				 bool is_param);
 };
 
-static inline void brcmnand_soc_data_bus_prepare(struct brcmnand_soc *soc)
+static inline void brcmnand_soc_data_bus_prepare(struct brcmnand_soc *soc,
+						 bool is_param)
 {
 	if (soc && soc->prepare_data_bus)
-		soc->prepare_data_bus(soc, true);
+		soc->prepare_data_bus(soc, true, is_param);
 }
 
-static inline void brcmnand_soc_data_bus_unprepare(struct brcmnand_soc *soc)
+static inline void brcmnand_soc_data_bus_unprepare(struct brcmnand_soc *soc,
+						   bool is_param)
 {
 	if (soc && soc->prepare_data_bus)
-		soc->prepare_data_bus(soc, false);
+		soc->prepare_data_bus(soc, false, is_param);
 }
 
 static inline u32 brcmnand_readl(void __iomem *addr)

drivers/mtd/nand/brcmnand/iproc_nand.c

@@ -74,7 +74,8 @@ static void iproc_nand_intc_set(struct brcmnand_soc *soc, bool en)
 	spin_unlock_irqrestore(&priv->idm_lock, flags);
 }
 
-static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare)
+static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare,
+				  bool is_param)
 {
 	struct iproc_nand_soc *priv =
 			container_of(soc, struct iproc_nand_soc, soc);
@@ -86,10 +87,19 @@ static void iproc_nand_apb_access(struct brcmnand_soc *soc, bool prepare)
 
 	val = brcmnand_readl(mmio);
 
-	if (prepare)
-		val |= IPROC_NAND_APB_LE_MODE;
-	else
+	/*
+	 * In the case of BE or when dealing with NAND data, alway configure
+	 * the APB bus to LE mode before accessing the FIFO and back to BE mode
+	 * after the access is done
+	 */
+	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) || !is_param) {
+		if (prepare)
+			val |= IPROC_NAND_APB_LE_MODE;
+		else
+			val &= ~IPROC_NAND_APB_LE_MODE;
+	} else { /* when in LE accessing the parameter page, keep APB in BE */
 		val &= ~IPROC_NAND_APB_LE_MODE;
+	}
 
 	brcmnand_writel(val, mmio);
 

drivers/mtd/nand/docg4.c

@@ -1249,8 +1249,7 @@ static void __init init_mtd_structs(struct mtd_info *mtd)
 	nand->options = NAND_BUSWIDTH_16 | NAND_NO_SUBPAGE_WRITE;
 	nand->IO_ADDR_R = nand->IO_ADDR_W = doc->virtadr + DOC_IOSPACE_DATA;
 	nand->controller = &nand->hwcontrol;
-	spin_lock_init(&nand->controller->lock);
-	init_waitqueue_head(&nand->controller->wq);
+	nand_hw_control_init(nand->controller);
 
 	/* methods */
 	nand->cmdfunc = docg4_command;

drivers/mtd/nand/fsl_elbc_nand.c

@@ -879,8 +879,7 @@ static int fsl_elbc_nand_probe(struct platform_device *pdev)
 		}
 		elbc_fcm_ctrl->counter++;
 
-		spin_lock_init(&elbc_fcm_ctrl->controller.lock);
-		init_waitqueue_head(&elbc_fcm_ctrl->controller.wq);
+		nand_hw_control_init(&elbc_fcm_ctrl->controller);
 		fsl_lbc_ctrl_dev->nand = elbc_fcm_ctrl;
 	} else {
 		elbc_fcm_ctrl = fsl_lbc_ctrl_dev->nand;

drivers/mtd/nand/fsl_ifc_nand.c

@@ -987,8 +987,7 @@ static int fsl_ifc_nand_probe(struct platform_device *dev)
 		ifc_nand_ctrl->addr = NULL;
 		fsl_ifc_ctrl_dev->nand = ifc_nand_ctrl;
 
-		spin_lock_init(&ifc_nand_ctrl->controller.lock);
-		init_waitqueue_head(&ifc_nand_ctrl->controller.wq);
+		nand_hw_control_init(&ifc_nand_ctrl->controller);
 	} else {
 		ifc_nand_ctrl = fsl_ifc_ctrl_dev->nand;
 	}

drivers/mtd/nand/gpmi-nand/gpmi-nand.c

@@ -318,7 +318,8 @@ static int legacy_set_geometry(struct gpmi_nand_data *this)
 		return -EINVAL;
 	}
 
-	geo->page_size = mtd->writesize + mtd->oobsize;
+	geo->page_size = mtd->writesize + geo->metadata_size +
+		(geo->gf_len * geo->ecc_strength * geo->ecc_chunk_count) / 8;
 	geo->payload_size = mtd->writesize;
 
 	/*

drivers/mtd/nand/jz4780_nand.c

@@ -368,9 +368,8 @@ static int jz4780_nand_probe(struct platform_device *pdev)
 	nfc->dev = dev;
 	nfc->num_banks = num_banks;
 
-	spin_lock_init(&nfc->controller.lock);
+	nand_hw_control_init(&nfc->controller);
 	INIT_LIST_HEAD(&nfc->chips);
-	init_waitqueue_head(&nfc->controller.wq);
 
 	ret = jz4780_nand_init_chips(nfc, pdev);
 	if (ret) {

drivers/mtd/nand/mxc_nand.c

@@ -152,6 +152,9 @@ struct mxc_nand_devtype_data {
 	void (*select_chip)(struct mtd_info *mtd, int chip);
 	int (*correct_data)(struct mtd_info *mtd, u_char *dat,
 			u_char *read_ecc, u_char *calc_ecc);
+	int (*setup_data_interface)(struct mtd_info *mtd,
+				    const struct nand_data_interface *conf,
+				    bool check_only);
 
 	/*
 	 * On i.MX21 the CONFIG2:INT bit cannot be read if interrupts are masked
@@ -1012,6 +1015,82 @@ static void preset_v1(struct mtd_info *mtd)
 	writew(0x4, NFC_V1_V2_WRPROT);
 }
 
+static int mxc_nand_v2_setup_data_interface(struct mtd_info *mtd,
+					const struct nand_data_interface *conf,
+					bool check_only)
+{
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
+	int tRC_min_ns, tRC_ps, ret;
+	unsigned long rate, rate_round;
+	const struct nand_sdr_timings *timings;
+	u16 config1;
+
+	timings = nand_get_sdr_timings(conf);
+	if (IS_ERR(timings))
+		return -ENOTSUPP;
+
+	config1 = readw(NFC_V1_V2_CONFIG1);
+
+	tRC_min_ns = timings->tRC_min / 1000;
+	rate = 1000000000 / tRC_min_ns;
+
+	/*
+	 * For tRC < 30ns we have to use EDO mode. In this case the controller
+	 * does one access per clock cycle. Otherwise the controller does one
+	 * access in two clock cycles, thus we have to double the rate to the
+	 * controller.
+	 */
+	if (tRC_min_ns < 30) {
+		rate_round = clk_round_rate(host->clk, rate);
+		config1 |= NFC_V2_CONFIG1_ONE_CYCLE;
+		tRC_ps = 1000000000 / (rate_round / 1000);
+	} else {
+		rate *= 2;
+		rate_round = clk_round_rate(host->clk, rate);
+		config1 &= ~NFC_V2_CONFIG1_ONE_CYCLE;
+		tRC_ps = 1000000000 / (rate_round / 1000 / 2);
+	}
+
+	/*
+	 * The timing values compared against are from the i.MX25 Automotive
+	 * datasheet, Table 50. NFC Timing Parameters
+	 */
+	if (timings->tCLS_min > tRC_ps - 1000 ||
+	    timings->tCLH_min > tRC_ps - 2000 ||
+	    timings->tCS_min > tRC_ps - 1000 ||
+	    timings->tCH_min > tRC_ps - 2000 ||
+	    timings->tWP_min > tRC_ps - 1500 ||
+	    timings->tALS_min > tRC_ps ||
+	    timings->tALH_min > tRC_ps - 3000 ||
+	    timings->tDS_min > tRC_ps ||
+	    timings->tDH_min > tRC_ps - 5000 ||
+	    timings->tWC_min > 2 * tRC_ps ||
+	    timings->tWH_min > tRC_ps - 2500 ||
+	    timings->tRR_min > 6 * tRC_ps ||
+	    timings->tRP_min > 3 * tRC_ps / 2 ||
+	    timings->tRC_min > 2 * tRC_ps ||
+	    timings->tREH_min > (tRC_ps / 2) - 2500) {
+		dev_dbg(host->dev, "Timing out of bounds\n");
+		return -EINVAL;
+	}
+
+	if (check_only)
+		return 0;
+
+	ret = clk_set_rate(host->clk, rate);
+	if (ret)
+		return ret;
+
+	writew(config1, NFC_V1_V2_CONFIG1);
+
+	dev_dbg(host->dev, "Setting rate to %ldHz, %s mode\n", rate_round,
+		config1 & NFC_V2_CONFIG1_ONE_CYCLE ? "One cycle (EDO)" :
+		"normal");
+
+	return 0;
+}
+
 static void preset_v2(struct mtd_info *mtd)
 {
 	struct nand_chip *nand_chip = mtd_to_nand(mtd);
@@ -1239,6 +1318,57 @@ static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
 	}
 }
 
+static int mxc_nand_onfi_set_features(struct mtd_info *mtd,
+				      struct nand_chip *chip, int addr,
+				      u8 *subfeature_param)
+{
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
+	int i;
+
+	if (!chip->onfi_version ||
+	    !(le16_to_cpu(chip->onfi_params.opt_cmd)
+	      & ONFI_OPT_CMD_SET_GET_FEATURES))
+		return -EINVAL;
+
+	host->buf_start = 0;
+
+	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
+		chip->write_byte(mtd, subfeature_param[i]);
+
+	memcpy32_toio(host->main_area0, host->data_buf, mtd->writesize);
+	host->devtype_data->send_cmd(host, NAND_CMD_SET_FEATURES, false);
+	mxc_do_addr_cycle(mtd, addr, -1);
+	host->devtype_data->send_page(mtd, NFC_INPUT);
+
+	return 0;
+}
+
+static int mxc_nand_onfi_get_features(struct mtd_info *mtd,
+				      struct nand_chip *chip, int addr,
+				      u8 *subfeature_param)
+{
+	struct nand_chip *nand_chip = mtd_to_nand(mtd);
+	struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
+	int i;
+
+	if (!chip->onfi_version ||
+	    !(le16_to_cpu(chip->onfi_params.opt_cmd)
+	      & ONFI_OPT_CMD_SET_GET_FEATURES))
+		return -EINVAL;
+
+	host->devtype_data->send_cmd(host, NAND_CMD_GET_FEATURES, false);
+	mxc_do_addr_cycle(mtd, addr, -1);
+	host->devtype_data->send_page(mtd, NFC_OUTPUT);
+	memcpy32_fromio(host->data_buf, host->main_area0, 512);
+	host->buf_start = 0;
+
+	for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
+		*subfeature_param++ = chip->read_byte(mtd);
+
+	return 0;
+}
+
 /*
  * The generic flash bbt decriptors overlap with our ecc
  * hardware, so define some i.MX specific ones.
@@ -1327,6 +1457,7 @@ static const struct mxc_nand_devtype_data imx25_nand_devtype_data = {
 	.ooblayout = &mxc_v2_ooblayout_ops,
 	.select_chip = mxc_nand_select_chip_v2,
 	.correct_data = mxc_nand_correct_data_v2_v3,
+	.setup_data_interface = mxc_nand_v2_setup_data_interface,
 	.irqpending_quirk = 0,
 	.needs_ip = 0,
 	.regs_offset = 0x1e00,
@@ -1434,7 +1565,7 @@ static const struct platform_device_id mxcnd_devtype[] = {
 };
 MODULE_DEVICE_TABLE(platform, mxcnd_devtype);
 
-#ifdef CONFIG_OF_MTD
+#ifdef CONFIG_OF
 static const struct of_device_id mxcnd_dt_ids[] = {
 	{
 		.compatible = "fsl,imx21-nand",
@@ -1513,6 +1644,8 @@ static int mxcnd_probe(struct platform_device *pdev)
 	this->read_word = mxc_nand_read_word;
 	this->write_buf = mxc_nand_write_buf;
 	this->read_buf = mxc_nand_read_buf;
+	this->onfi_set_features = mxc_nand_onfi_set_features;
+	this->onfi_get_features = mxc_nand_onfi_get_features;
 
 	host->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(host->clk))
@@ -1533,6 +1666,8 @@ static int mxcnd_probe(struct platform_device *pdev)
 	if (err < 0)
 		return err;
 
+	this->setup_data_interface = host->devtype_data->setup_data_interface;
+
 	if (host->devtype_data->needs_ip) {
 		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 		host->regs_ip = devm_ioremap_resource(&pdev->dev, res);

drivers/mtd/nand/nand_bbt.c

@@ -604,6 +604,100 @@ static void search_read_bbts(struct mtd_info *mtd, uint8_t *buf,
 		search_bbt(mtd, buf, md);
 }
 
+/**
+ * get_bbt_block - Get the first valid eraseblock suitable to store a BBT
+ * @this: the NAND device
+ * @td: the BBT description
+ * @md: the mirror BBT descriptor
+ * @chip: the CHIP selector
+ *
+ * This functions returns a positive block number pointing a valid eraseblock
+ * suitable to store a BBT (i.e. in the range reserved for BBT), or -ENOSPC if
+ * all blocks are already used of marked bad. If td->pages[chip] was already
+ * pointing to a valid block we re-use it, otherwise we search for the next
+ * valid one.
+ */
+static int get_bbt_block(struct nand_chip *this, struct nand_bbt_descr *td,
+			 struct nand_bbt_descr *md, int chip)
+{
+	int startblock, dir, page, numblocks, i;
+
+	/*
+	 * There was already a version of the table, reuse the page. This
+	 * applies for absolute placement too, as we have the page number in
+	 * td->pages.
+	 */
+	if (td->pages[chip] != -1)
+		return td->pages[chip] >>
+				(this->bbt_erase_shift - this->page_shift);
+
+	numblocks = (int)(this->chipsize >> this->bbt_erase_shift);
+	if (!(td->options & NAND_BBT_PERCHIP))
+		numblocks *= this->numchips;
+
+	/*
+	 * Automatic placement of the bad block table. Search direction
+	 * top -> down?
+	 */
+	if (td->options & NAND_BBT_LASTBLOCK) {
+		startblock = numblocks * (chip + 1) - 1;
+		dir = -1;
+	} else {
+		startblock = chip * numblocks;
+		dir = 1;
+	}
+
+	for (i = 0; i < td->maxblocks; i++) {
+		int block = startblock + dir * i;
+
+		/* Check, if the block is bad */
+		switch (bbt_get_entry(this, block)) {
+		case BBT_BLOCK_WORN:
+		case BBT_BLOCK_FACTORY_BAD:
+			continue;
+		}
+
+		page = block << (this->bbt_erase_shift - this->page_shift);
+
+		/* Check, if the block is used by the mirror table */
+		if (!md || md->pages[chip] != page)
+			return block;
+	}
+
+	return -ENOSPC;
+}
+
+/**
+ * mark_bbt_block_bad - Mark one of the block reserved for BBT bad
+ * @this: the NAND device
+ * @td: the BBT description
+ * @chip: the CHIP selector
+ * @block: the BBT block to mark
+ *
+ * Blocks reserved for BBT can become bad. This functions is an helper to mark
+ * such blocks as bad. It takes care of updating the in-memory BBT, marking the
+ * block as bad using a bad block marker and invalidating the associated
+ * td->pages[] entry.
+ */
+static void mark_bbt_block_bad(struct nand_chip *this,
+			       struct nand_bbt_descr *td,
+			       int chip, int block)
+{
+	struct mtd_info *mtd = nand_to_mtd(this);
+	loff_t to;
+	int res;
+
+	bbt_mark_entry(this, block, BBT_BLOCK_WORN);
+
+	to = (loff_t)block << this->bbt_erase_shift;
+	res = this->block_markbad(mtd, to);
+	if (res)
+		pr_warn("nand_bbt: error %d while marking block %d bad\n",
+			res, block);
+
+	td->pages[chip] = -1;
+}
+
 /**
  * write_bbt - [GENERIC] (Re)write the bad block table
  * @mtd: MTD device structure
@@ -621,7 +715,7 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
 	struct nand_chip *this = mtd_to_nand(mtd);
 	struct erase_info einfo;
 	int i, res, chip = 0;
-	int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
+	int bits, page, offs, numblocks, sft, sftmsk;
 	int nrchips, pageoffs, ooboffs;
 	uint8_t msk[4];
 	uint8_t rcode = td->reserved_block_code;
@@ -652,46 +746,21 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
 	}
 
 	/* Loop through the chips */
-	for (; chip < nrchips; chip++) {
-		/*
-		 * There was already a version of the table, reuse the page
-		 * This applies for absolute placement too, as we have the
-		 * page nr. in td->pages.
-		 */
-		if (td->pages[chip] != -1) {
-			page = td->pages[chip];
-			goto write;
+	while (chip < nrchips) {
+		int block;
+
+		block = get_bbt_block(this, td, md, chip);
+		if (block < 0) {
+			pr_err("No space left to write bad block table\n");
+			res = block;
+			goto outerr;
 		}
 
 		/*
-		 * Automatic placement of the bad block table. Search direction
-		 * top -> down?
+		 * get_bbt_block() returns a block number, shift the value to
+		 * get a page number.
 		 */
-		if (td->options & NAND_BBT_LASTBLOCK) {
-			startblock = numblocks * (chip + 1) - 1;
-			dir = -1;
-		} else {
-			startblock = chip * numblocks;
-			dir = 1;
-		}
-
-		for (i = 0; i < td->maxblocks; i++) {
-			int block = startblock + dir * i;
-			/* Check, if the block is bad */
-			switch (bbt_get_entry(this, block)) {
-			case BBT_BLOCK_WORN:
-			case BBT_BLOCK_FACTORY_BAD:
-				continue;
-			}
-			page = block <<
-				(this->bbt_erase_shift - this->page_shift);
-			/* Check, if the block is used by the mirror table */
-			if (!md || md->pages[chip] != page)
-				goto write;
-		}
-		pr_err("No space left to write bad block table\n");
-		return -ENOSPC;
-	write:
+		page = block << (this->bbt_erase_shift - this->page_shift);
 
 		/* Set up shift count and masks for the flash table */
 		bits = td->options & NAND_BBT_NRBITS_MSK;
@@ -787,20 +856,28 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
 		einfo.addr = to;
 		einfo.len = 1 << this->bbt_erase_shift;
 		res = nand_erase_nand(mtd, &einfo, 1);
-		if (res < 0)
-			goto outerr;
+		if (res < 0) {
+			pr_warn("nand_bbt: error while erasing BBT block %d\n",
+				res);
+			mark_bbt_block_bad(this, td, chip, block);
+			continue;
+		}
 
 		res = scan_write_bbt(mtd, to, len, buf,
 				td->options & NAND_BBT_NO_OOB ? NULL :
 				&buf[len]);
-		if (res < 0)
-			goto outerr;
+		if (res < 0) {
+			pr_warn("nand_bbt: error while writing BBT block %d\n",
+				res);
+			mark_bbt_block_bad(this, td, chip, block);
+			continue;
+		}
 
 		pr_info("Bad block table written to 0x%012llx, version 0x%02X\n",
 			 (unsigned long long)to, td->version[chip]);
 
 		/* Mark it as used */
-		td->pages[chip] = page;
+		td->pages[chip++] = page;
 	}
 	return 0;
 

drivers/mtd/nand/ndfc.c

@@ -218,8 +218,7 @@ static int ndfc_probe(struct platform_device *ofdev)
 	ndfc = &ndfc_ctrl[cs];
 	ndfc->chip_select = cs;
 
-	spin_lock_init(&ndfc->ndfc_control.lock);
-	init_waitqueue_head(&ndfc->ndfc_control.wq);
+	nand_hw_control_init(&ndfc->ndfc_control);
 	ndfc->ofdev = ofdev;
 	dev_set_drvdata(&ofdev->dev, ndfc);
 

drivers/mtd/nand/pxa3xx_nand.c

@@ -1810,8 +1810,7 @@ static int alloc_nand_resource(struct platform_device *pdev)
 		chip->cmdfunc		= nand_cmdfunc;
 	}
 
-	spin_lock_init(&chip->controller->lock);
-	init_waitqueue_head(&chip->controller->wq);
+	nand_hw_control_init(chip->controller);
 	info->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(info->clk)) {
 		dev_err(&pdev->dev, "failed to get nand clock\n");

drivers/mtd/nand/qcom_nandc.c

@@ -1957,8 +1957,7 @@ static int qcom_nandc_alloc(struct qcom_nand_controller *nandc)
 	INIT_LIST_HEAD(&nandc->desc_list);
 	INIT_LIST_HEAD(&nandc->host_list);
 
-	spin_lock_init(&nandc->controller.lock);
-	init_waitqueue_head(&nandc->controller.wq);
+	nand_hw_control_init(&nandc->controller);
 
 	return 0;
 }

drivers/mtd/nand/s3c2410.c

@@ -180,7 +180,7 @@ struct s3c2410_nand_info {
 
 	enum s3c_cpu_type		cpu_type;
 
-#ifdef CONFIG_CPU_FREQ
+#ifdef CONFIG_ARM_S3C24XX_CPUFREQ
 	struct notifier_block	freq_transition;
 #endif
 };
@@ -701,7 +701,7 @@ static void s3c2440_nand_write_buf(struct mtd_info *mtd, const u_char *buf,
 
 /* cpufreq driver support */
 
-#ifdef CONFIG_CPU_FREQ
+#ifdef CONFIG_ARM_S3C24XX_CPUFREQ
 
 static int s3c2410_nand_cpufreq_transition(struct notifier_block *nb,
 					  unsigned long val, void *data)
@@ -977,8 +977,7 @@ static int s3c24xx_nand_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, info);
 
-	spin_lock_init(&info->controller.lock);
-	init_waitqueue_head(&info->controller.wq);
+	nand_hw_control_init(&info->controller);
 
 	/* get the clock source and enable it */
 

drivers/mtd/nand/sh_flctl.c

@@ -397,7 +397,7 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
 	struct dma_chan *chan;
 	enum dma_transfer_direction tr_dir;
 	dma_addr_t dma_addr;
-	dma_cookie_t cookie = -EINVAL;
+	dma_cookie_t cookie;
 	uint32_t reg;
 	int ret;
 
@@ -423,6 +423,12 @@ static int flctl_dma_fifo0_transfer(struct sh_flctl *flctl, unsigned long *buf,
 		desc->callback = flctl_dma_complete;
 		desc->callback_param = flctl;
 		cookie = dmaengine_submit(desc);
+		if (dma_submit_error(cookie)) {
+			ret = dma_submit_error(cookie);
+			dev_warn(&flctl->pdev->dev,
+				 "DMA submit failed, falling back to PIO\n");
+			goto out;
+		}
 
 		dma_async_issue_pending(chan);
 	} else {

drivers/mtd/nand/sunxi_nand.c

@@ -1572,14 +1572,22 @@ static int _sunxi_nand_lookup_timing(const s32 *lut, int lut_size, u32 duration,
 #define sunxi_nand_lookup_timing(l, p, c) \
 			_sunxi_nand_lookup_timing(l, ARRAY_SIZE(l), p, c)
 
-static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
-				       const struct nand_sdr_timings *timings)
+static int sunxi_nfc_setup_data_interface(struct mtd_info *mtd,
+					const struct nand_data_interface *conf,
+					bool check_only)
 {
+	struct nand_chip *nand = mtd_to_nand(mtd);
+	struct sunxi_nand_chip *chip = to_sunxi_nand(nand);
 	struct sunxi_nfc *nfc = to_sunxi_nfc(chip->nand.controller);
+	const struct nand_sdr_timings *timings;
 	u32 min_clk_period = 0;
 	s32 tWB, tADL, tWHR, tRHW, tCAD;
 	long real_clk_rate;
 
+	timings = nand_get_sdr_timings(conf);
+	if (IS_ERR(timings))
+		return -ENOTSUPP;
+
 	/* T1 <=> tCLS */
 	if (timings->tCLS_min > min_clk_period)
 		min_clk_period = timings->tCLS_min;
@@ -1679,6 +1687,9 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
 		return tRHW;
 	}
 
+	if (check_only)
+		return 0;
+
 	/*
 	 * TODO: according to ONFI specs this value only applies for DDR NAND,
 	 * but Allwinner seems to set this to 0x7. Mimic them for now.
@@ -1712,44 +1723,6 @@ static int sunxi_nand_chip_set_timings(struct sunxi_nand_chip *chip,
 	return 0;
 }
 
-static int sunxi_nand_chip_init_timings(struct sunxi_nand_chip *chip,
-					struct device_node *np)
-{
-	struct mtd_info *mtd = nand_to_mtd(&chip->nand);
-	const struct nand_sdr_timings *timings;
-	int ret;
-	int mode;
-
-	mode = onfi_get_async_timing_mode(&chip->nand);
-	if (mode == ONFI_TIMING_MODE_UNKNOWN) {
-		mode = chip->nand.onfi_timing_mode_default;
-	} else {
-		uint8_t feature[ONFI_SUBFEATURE_PARAM_LEN] = {};
-		int i;
-
-		mode = fls(mode) - 1;
-		if (mode < 0)
-			mode = 0;
-
-		feature[0] = mode;
-		for (i = 0; i < chip->nsels; i++) {
-			chip->nand.select_chip(mtd, i);
-			ret = chip->nand.onfi_set_features(mtd,	&chip->nand,
-						ONFI_FEATURE_ADDR_TIMING_MODE,
-						feature);
-			chip->nand.select_chip(mtd, -1);
-			if (ret)
-				return ret;
-		}
-	}
-
-	timings = onfi_async_timing_mode_to_sdr_timings(mode);
-	if (IS_ERR(timings))
-		return PTR_ERR(timings);
-
-	return sunxi_nand_chip_set_timings(chip, timings);
-}
-
 static int sunxi_nand_ooblayout_ecc(struct mtd_info *mtd, int section,
 				    struct mtd_oob_region *oobregion)
 {
@@ -1814,6 +1787,35 @@ static int sunxi_nand_hw_common_ecc_ctrl_init(struct mtd_info *mtd,
 	int ret;
 	int i;
 
+	if (ecc->options & NAND_ECC_MAXIMIZE) {
+		int bytes;
+
+		ecc->size = 1024;
+		nsectors = mtd->writesize / ecc->size;
+
+		/* Reserve 2 bytes for the BBM */
+		bytes = (mtd->oobsize - 2) / nsectors;
+
+		/* 4 non-ECC bytes are added before each ECC bytes section */
+		bytes -= 4;
+
+		/* and bytes has to be even. */
+		if (bytes % 2)
+			bytes--;
+
+		ecc->strength = bytes * 8 / fls(8 * ecc->size);
+
+		for (i = 0; i < ARRAY_SIZE(strengths); i++) {
+			if (strengths[i] > ecc->strength)
+				break;
+		}
+
+		if (!i)
+			ecc->strength = 0;
+		else
+			ecc->strength = strengths[i - 1];
+	}
+
 	if (ecc->size != 512 && ecc->size != 1024)
 		return -EINVAL;
 
@@ -1975,7 +1977,6 @@ static int sunxi_nand_ecc_init(struct mtd_info *mtd, struct nand_ecc_ctrl *ecc,
 static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
 				struct device_node *np)
 {
-	const struct nand_sdr_timings *timings;
 	struct sunxi_nand_chip *chip;
 	struct mtd_info *mtd;
 	struct nand_chip *nand;
@@ -2065,25 +2066,11 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
 	nand->read_buf = sunxi_nfc_read_buf;
 	nand->write_buf = sunxi_nfc_write_buf;
 	nand->read_byte = sunxi_nfc_read_byte;
+	nand->setup_data_interface = sunxi_nfc_setup_data_interface;
 
 	mtd = nand_to_mtd(nand);
 	mtd->dev.parent = dev;
 
-	timings = onfi_async_timing_mode_to_sdr_timings(0);
-	if (IS_ERR(timings)) {
-		ret = PTR_ERR(timings);
-		dev_err(dev,
-			"could not retrieve timings for ONFI mode 0: %d\n",
-			ret);
-		return ret;
-	}
-
-	ret = sunxi_nand_chip_set_timings(chip, timings);
-	if (ret) {
-		dev_err(dev, "could not configure chip timings: %d\n", ret);
-		return ret;
-	}
-
 	ret = nand_scan_ident(mtd, nsels, NULL);
 	if (ret)
 		return ret;
@@ -2096,12 +2083,6 @@ static int sunxi_nand_chip_init(struct device *dev, struct sunxi_nfc *nfc,
 
 	nand->options |= NAND_SUBPAGE_READ;
 
-	ret = sunxi_nand_chip_init_timings(chip, np);
-	if (ret) {
-		dev_err(dev, "could not configure chip timings: %d\n", ret);
-		return ret;
-	}
-
 	ret = sunxi_nand_ecc_init(mtd, &nand->ecc, np);
 	if (ret) {
 		dev_err(dev, "ECC init failed: %d\n", ret);
@@ -2175,8 +2156,7 @@ static int sunxi_nfc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	nfc->dev = dev;
-	spin_lock_init(&nfc->controller.lock);
-	init_waitqueue_head(&nfc->controller.wq);
+	nand_hw_control_init(&nfc->controller);
 	INIT_LIST_HEAD(&nfc->chips);
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);

drivers/mtd/nand/txx9ndfmc.c

@@ -303,8 +303,7 @@ static int __init txx9ndfmc_probe(struct platform_device *dev)
 	dev_info(&dev->dev, "CLK:%ldMHz HOLD:%d SPW:%d\n",
 		 (gbusclk + 500000) / 1000000, hold, spw);
 
-	spin_lock_init(&drvdata->hw_control.lock);
-	init_waitqueue_head(&drvdata->hw_control.wq);
+	nand_hw_control_init(&drvdata->hw_control);
 
 	platform_set_drvdata(dev, drvdata);
 	txx9ndfmc_initialize(dev);

drivers/of/Kconfig

@@ -90,10 +90,6 @@ config OF_PCI_IRQ
 	help
 	  OpenFirmware PCI IRQ routing helpers
 
-config OF_MTD
-	depends on MTD
-	def_bool y
-
 config OF_RESERVED_MEM
 	depends on OF_EARLY_FLATTREE
 	bool

include/linux/mtd/mtd.h

@@ -127,6 +127,82 @@ struct mtd_ooblayout_ops {
 		    struct mtd_oob_region *oobfree);
 };
 
+/**
+ * struct mtd_pairing_info - page pairing information
+ *
+ * @pair: pair id
+ * @group: group id
+ *
+ * The term "pair" is used here, even though TLC NANDs might group pages by 3
+ * (3 bits in a single cell). A pair should regroup all pages that are sharing
+ * the same cell. Pairs are then indexed in ascending order.
+ *
+ * @group is defining the position of a page in a given pair. It can also be
+ * seen as the bit position in the cell: page attached to bit 0 belongs to
+ * group 0, page attached to bit 1 belongs to group 1, etc.
+ *
+ * Example:
+ * The H27UCG8T2BTR-BC datasheet describes the following pairing scheme:
+ *
+ *		group-0		group-1
+ *
+ *  pair-0	page-0		page-4
+ *  pair-1	page-1		page-5
+ *  pair-2	page-2		page-8
+ *  ...
+ *  pair-127	page-251	page-255
+ *
+ *
+ * Note that the "group" and "pair" terms were extracted from Samsung and
+ * Hynix datasheets, and might be referenced under other names in other
+ * datasheets (Micron is describing this concept as "shared pages").
+ */
+struct mtd_pairing_info {
+	int pair;
+	int group;
+};
+
+/**
+ * struct mtd_pairing_scheme - page pairing scheme description
+ *
+ * @ngroups: number of groups. Should be related to the number of bits
+ *	     per cell.
+ * @get_info: converts a write-unit (page number within an erase block) into
+ *	      mtd_pairing information (pair + group). This function should
+ *	      fill the info parameter based on the wunit index or return
+ *	      -EINVAL if the wunit parameter is invalid.
+ * @get_wunit: converts pairing information into a write-unit (page) number.
+ *	       This function should return the wunit index pointed by the
+ *	       pairing information described in the info argument. It should
+ *	       return -EINVAL, if there's no wunit corresponding to the
+ *	       passed pairing information.
+ *
+ * See mtd_pairing_info documentation for a detailed explanation of the
+ * pair and group concepts.
+ *
+ * The mtd_pairing_scheme structure provides a generic solution to represent
+ * NAND page pairing scheme. Instead of exposing two big tables to do the
+ * write-unit <-> (pair + group) conversions, we ask the MTD drivers to
+ * implement the ->get_info() and ->get_wunit() functions.
+ *
+ * MTD users will then be able to query these information by using the
+ * mtd_pairing_info_to_wunit() and mtd_wunit_to_pairing_info() helpers.
+ *
+ * @ngroups is here to help MTD users iterating over all the pages in a
+ * given pair. This value can be retrieved by MTD users using the
+ * mtd_pairing_groups() helper.
+ *
+ * Examples are given in the mtd_pairing_info_to_wunit() and
+ * mtd_wunit_to_pairing_info() documentation.
+ */
+struct mtd_pairing_scheme {
+	int ngroups;
+	int (*get_info)(struct mtd_info *mtd, int wunit,
+			struct mtd_pairing_info *info);
+	int (*get_wunit)(struct mtd_info *mtd,
+			 const struct mtd_pairing_info *info);
+};
+
 struct module;	/* only needed for owner field in mtd_info */
 
 struct mtd_info {
@@ -188,6 +264,9 @@ struct mtd_info {
 	/* OOB layout description */
 	const struct mtd_ooblayout_ops *ooblayout;
 
+	/* NAND pairing scheme, only provided for MLC/TLC NANDs */
+	const struct mtd_pairing_scheme *pairing;
+
 	/* the ecc step size. */
 	unsigned int ecc_step_size;
 
@@ -296,6 +375,12 @@ static inline void mtd_set_ooblayout(struct mtd_info *mtd,
 	mtd->ooblayout = ooblayout;
 }
 
+static inline void mtd_set_pairing_scheme(struct mtd_info *mtd,
+				const struct mtd_pairing_scheme *pairing)
+{
+	mtd->pairing = pairing;
+}
+
 static inline void mtd_set_of_node(struct mtd_info *mtd,
 				   struct device_node *np)
 {
@@ -312,6 +397,11 @@ static inline int mtd_oobavail(struct mtd_info *mtd, struct mtd_oob_ops *ops)
 	return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize;
 }
 
+int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
+			      struct mtd_pairing_info *info);
+int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
+			      const struct mtd_pairing_info *info);
+int mtd_pairing_groups(struct mtd_info *mtd);
 int mtd_erase(struct mtd_info *mtd, struct erase_info *instr);
 int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	      void **virt, resource_size_t *phys);
@@ -397,6 +487,23 @@ static inline uint32_t mtd_mod_by_ws(uint64_t sz, struct mtd_info *mtd)
 	return do_div(sz, mtd->writesize);
 }
 
+static inline int mtd_wunit_per_eb(struct mtd_info *mtd)
+{
+	return mtd->erasesize / mtd->writesize;
+}
+
+static inline int mtd_offset_to_wunit(struct mtd_info *mtd, loff_t offs)
+{
+	return mtd_div_by_ws(mtd_mod_by_eb(offs, mtd), mtd);
+}
+
+static inline loff_t mtd_wunit_to_offset(struct mtd_info *mtd, loff_t base,
+					 int wunit)
+{
+	return base + (wunit * mtd->writesize);
+}
+
+
 static inline int mtd_has_oob(const struct mtd_info *mtd)
 {
 	return mtd->_read_oob && mtd->_write_oob;