mtd: nand: move raw NAND related code to the raw/ subdir

As part of the process of sharing more code between different NAND
based devices, we need to move all raw NAND related code to the raw/
subdirectory.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>

1 files changed, 1012 insertions, 0 deletions

diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
new file mode 100644
index 000000000000..9de29c9afb0c
--- /dev/null
+++ b/drivers/mtd/nand/raw/atmel/pmecc.c
@@ -0,0 +1,1012 @@
+/*
+ * Copyright 2017 ATMEL
+ * Copyright 2017 Free Electrons
+ *
+ * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
+ *
+ * Derived from the atmel_nand.c driver which contained the following
+ * copyrights:
+ *
+ *   Copyright 2003 Rick Bronson
+ *
+ *   Derived from drivers/mtd/nand/autcpu12.c (removed in v3.8)
+ *	Copyright 2001 Thomas Gleixner (gleixner@autronix.de)
+ *
+ *   Derived from drivers/mtd/spia.c (removed in v3.8)
+ *	Copyright 2000 Steven J. Hill (sjhill@cotw.com)
+ *
+ *   Add Hardware ECC support for AT91SAM9260 / AT91SAM9263
+ *	Richard Genoud (richard.genoud@gmail.com), Adeneo Copyright 2007
+ *
+ *   Derived from Das U-Boot source code
+ *	(u-boot-1.1.5/board/atmel/at91sam9263ek/nand.c)
+ *      Copyright 2006 ATMEL Rousset, Lacressonniere Nicolas
+ *
+ *   Add Programmable Multibit ECC support for various AT91 SoC
+ *	Copyright 2012 ATMEL, Hong Xu
+ *
+ *   Add Nand Flash Controller support for SAMA5 SoC
+ *	Copyright 2013 ATMEL, Josh Wu (josh.wu@atmel.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * The PMECC is an hardware assisted BCH engine, which means part of the
+ * ECC algorithm is left to the software. The hardware/software repartition
+ * is explained in the "PMECC Controller Functional Description" chapter in
+ * Atmel datasheets, and some of the functions in this file are directly
+ * implementing the algorithms described in the "Software Implementation"
+ * sub-section.
+ *
+ * TODO: it seems that the software BCH implementation in lib/bch.c is already
+ * providing some of the logic we are implementing here. It would be smart
+ * to expose the needed lib/bch.c helpers/functions and re-use them here.
+ */
+
+#include <linux/genalloc.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mtd/rawnand.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include "pmecc.h"
+
+/* Galois field dimension */
+#define PMECC_GF_DIMENSION_13			13
+#define PMECC_GF_DIMENSION_14			14
+
+/* Primitive Polynomial used by PMECC */
+#define PMECC_GF_13_PRIMITIVE_POLY		0x201b
+#define PMECC_GF_14_PRIMITIVE_POLY		0x4443
+
+#define PMECC_LOOKUP_TABLE_SIZE_512		0x2000
+#define PMECC_LOOKUP_TABLE_SIZE_1024		0x4000
+
+/* Time out value for reading PMECC status register */
+#define PMECC_MAX_TIMEOUT_MS			100
+
+/* PMECC Register Definitions */
+#define ATMEL_PMECC_CFG				0x0
+#define PMECC_CFG_BCH_STRENGTH(x)		(x)
+#define PMECC_CFG_BCH_STRENGTH_MASK		GENMASK(2, 0)
+#define PMECC_CFG_SECTOR512			(0 << 4)
+#define PMECC_CFG_SECTOR1024			(1 << 4)
+#define PMECC_CFG_NSECTORS(x)			((fls(x) - 1) << 8)
+#define PMECC_CFG_READ_OP			(0 << 12)
+#define PMECC_CFG_WRITE_OP			(1 << 12)
+#define PMECC_CFG_SPARE_ENABLE			BIT(16)
+#define PMECC_CFG_AUTO_ENABLE			BIT(20)
+
+#define ATMEL_PMECC_SAREA			0x4
+#define ATMEL_PMECC_SADDR			0x8
+#define ATMEL_PMECC_EADDR			0xc
+
+#define ATMEL_PMECC_CLK				0x10
+#define PMECC_CLK_133MHZ			(2 << 0)
+
+#define ATMEL_PMECC_CTRL			0x14
+#define PMECC_CTRL_RST				BIT(0)
+#define PMECC_CTRL_DATA				BIT(1)
+#define PMECC_CTRL_USER				BIT(2)
+#define PMECC_CTRL_ENABLE			BIT(4)
+#define PMECC_CTRL_DISABLE			BIT(5)
+
+#define ATMEL_PMECC_SR				0x18
+#define PMECC_SR_BUSY				BIT(0)
+#define PMECC_SR_ENABLE				BIT(4)
+
+#define ATMEL_PMECC_IER				0x1c
+#define ATMEL_PMECC_IDR				0x20
+#define ATMEL_PMECC_IMR				0x24
+#define ATMEL_PMECC_ISR				0x28
+#define PMECC_ERROR_INT				BIT(0)
+
+#define ATMEL_PMECC_ECC(sector, n)		\
+	((((sector) + 1) * 0x40) + (n))
+
+#define ATMEL_PMECC_REM(sector, n)		\
+	((((sector) + 1) * 0x40) + ((n) * 4) + 0x200)
+
+/* PMERRLOC Register Definitions */
+#define ATMEL_PMERRLOC_ELCFG			0x0
+#define PMERRLOC_ELCFG_SECTOR_512		(0 << 0)
+#define PMERRLOC_ELCFG_SECTOR_1024		(1 << 0)
+#define PMERRLOC_ELCFG_NUM_ERRORS(n)		((n) << 16)
+
+#define ATMEL_PMERRLOC_ELPRIM			0x4
+#define ATMEL_PMERRLOC_ELEN			0x8
+#define ATMEL_PMERRLOC_ELDIS			0xc
+#define PMERRLOC_DISABLE			BIT(0)
+
+#define ATMEL_PMERRLOC_ELSR			0x10
+#define PMERRLOC_ELSR_BUSY			BIT(0)
+
+#define ATMEL_PMERRLOC_ELIER			0x14
+#define ATMEL_PMERRLOC_ELIDR			0x18
+#define ATMEL_PMERRLOC_ELIMR			0x1c
+#define ATMEL_PMERRLOC_ELISR			0x20
+#define PMERRLOC_ERR_NUM_MASK			GENMASK(12, 8)
+#define PMERRLOC_CALC_DONE			BIT(0)
+
+#define ATMEL_PMERRLOC_SIGMA(x)			(((x) * 0x4) + 0x28)
+
+#define ATMEL_PMERRLOC_EL(offs, x)		(((x) * 0x4) + (offs))
+
+struct atmel_pmecc_gf_tables {
+	u16 *alpha_to;
+	u16 *index_of;
+};
+
+struct atmel_pmecc_caps {
+	const int *strengths;
+	int nstrengths;
+	int el_offset;
+	bool correct_erased_chunks;
+};
+
+struct atmel_pmecc {
+	struct device *dev;
+	const struct atmel_pmecc_caps *caps;
+
+	struct {
+		void __iomem *base;
+		void __iomem *errloc;
+	} regs;
+
+	struct mutex lock;
+};
+
+struct atmel_pmecc_user_conf_cache {
+	u32 cfg;
+	u32 sarea;
+	u32 saddr;
+	u32 eaddr;
+};
+
+struct atmel_pmecc_user {
+	struct atmel_pmecc_user_conf_cache cache;
+	struct atmel_pmecc *pmecc;
+	const struct atmel_pmecc_gf_tables *gf_tables;
+	int eccbytes;
+	s16 *partial_syn;
+	s16 *si;
+	s16 *lmu;
+	s16 *smu;
+	s32 *mu;
+	s32 *dmu;
+	s32 *delta;
+	u32 isr;
+};
+
+static DEFINE_MUTEX(pmecc_gf_tables_lock);
+static const struct atmel_pmecc_gf_tables *pmecc_gf_tables_512;
+static const struct atmel_pmecc_gf_tables *pmecc_gf_tables_1024;
+
+static inline int deg(unsigned int poly)
+{
+	/* polynomial degree is the most-significant bit index */
+	return fls(poly) - 1;
+}
+
+static int atmel_pmecc_build_gf_tables(int mm, unsigned int poly,
+				       struct atmel_pmecc_gf_tables *gf_tables)
+{
+	unsigned int i, x = 1;
+	const unsigned int k = BIT(deg(poly));
+	unsigned int nn = BIT(mm) - 1;
+
+	/* primitive polynomial must be of degree m */
+	if (k != (1u << mm))
+		return -EINVAL;
+
+	for (i = 0; i < nn; i++) {
+		gf_tables->alpha_to[i] = x;
+		gf_tables->index_of[x] = i;
+		if (i && (x == 1))
+			/* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
+			return -EINVAL;
+		x <<= 1;
+		if (x & k)
+			x ^= poly;
+	}
+	gf_tables->alpha_to[nn] = 1;
+	gf_tables->index_of[0] = 0;
+
+	return 0;
+}
+
+static const struct atmel_pmecc_gf_tables *
+atmel_pmecc_create_gf_tables(const struct atmel_pmecc_user_req *req)
+{
+	struct atmel_pmecc_gf_tables *gf_tables;
+	unsigned int poly, degree, table_size;
+	int ret;
+
+	if (req->ecc.sectorsize == 512) {
+		degree = PMECC_GF_DIMENSION_13;
+		poly = PMECC_GF_13_PRIMITIVE_POLY;
+		table_size = PMECC_LOOKUP_TABLE_SIZE_512;
+	} else {
+		degree = PMECC_GF_DIMENSION_14;
+		poly = PMECC_GF_14_PRIMITIVE_POLY;
+		table_size = PMECC_LOOKUP_TABLE_SIZE_1024;
+	}
+
+	gf_tables = kzalloc(sizeof(*gf_tables) +
+			    (2 * table_size * sizeof(u16)),
+			    GFP_KERNEL);
+	if (!gf_tables)
+		return ERR_PTR(-ENOMEM);
+
+	gf_tables->alpha_to = (void *)(gf_tables + 1);
+	gf_tables->index_of = gf_tables->alpha_to + table_size;
+
+	ret = atmel_pmecc_build_gf_tables(degree, poly, gf_tables);
+	if (ret) {
+		kfree(gf_tables);
+		return ERR_PTR(ret);
+	}
+
+	return gf_tables;
+}
+
+static const struct atmel_pmecc_gf_tables *
+atmel_pmecc_get_gf_tables(const struct atmel_pmecc_user_req *req)
+{
+	const struct atmel_pmecc_gf_tables **gf_tables, *ret;
+
+	mutex_lock(&pmecc_gf_tables_lock);
+	if (req->ecc.sectorsize == 512)
+		gf_tables = &pmecc_gf_tables_512;
+	else
+		gf_tables = &pmecc_gf_tables_1024;
+
+	ret = *gf_tables;
+
+	if (!ret) {
+		ret = atmel_pmecc_create_gf_tables(req);
+		if (!IS_ERR(ret))
+			*gf_tables = ret;
+	}
+	mutex_unlock(&pmecc_gf_tables_lock);
+
+	return ret;
+}
+
+static int atmel_pmecc_prepare_user_req(struct atmel_pmecc *pmecc,
+					struct atmel_pmecc_user_req *req)
+{
+	int i, max_eccbytes, eccbytes = 0, eccstrength = 0;
+
+	if (req->pagesize <= 0 || req->oobsize <= 0 || req->ecc.bytes <= 0)
+		return -EINVAL;
+
+	if (req->ecc.ooboffset >= 0 &&
+	    req->ecc.ooboffset + req->ecc.bytes > req->oobsize)
+		return -EINVAL;
+
+	if (req->ecc.sectorsize == ATMEL_PMECC_SECTOR_SIZE_AUTO) {
+		if (req->ecc.strength != ATMEL_PMECC_MAXIMIZE_ECC_STRENGTH)
+			return -EINVAL;
+
+		if (req->pagesize > 512)
+			req->ecc.sectorsize = 1024;
+		else
+			req->ecc.sectorsize = 512;
+	}
+
+	if (req->ecc.sectorsize != 512 && req->ecc.sectorsize != 1024)
+		return -EINVAL;
+
+	if (req->pagesize % req->ecc.sectorsize)
+		return -EINVAL;
+
+	req->ecc.nsectors = req->pagesize / req->ecc.sectorsize;
+
+	max_eccbytes = req->ecc.bytes;
+
+	for (i = 0; i < pmecc->caps->nstrengths; i++) {
+		int nbytes, strength = pmecc->caps->strengths[i];
+
+		if (req->ecc.strength != ATMEL_PMECC_MAXIMIZE_ECC_STRENGTH &&
+		    strength < req->ecc.strength)
+			continue;
+
+		nbytes = DIV_ROUND_UP(strength * fls(8 * req->ecc.sectorsize),
+				      8);
+		nbytes *= req->ecc.nsectors;
+
+		if (nbytes > max_eccbytes)
+			break;
+
+		eccstrength = strength;
+		eccbytes = nbytes;
+
+		if (req->ecc.strength != ATMEL_PMECC_MAXIMIZE_ECC_STRENGTH)
+			break;
+	}
+
+	if (!eccstrength)
+		return -EINVAL;
+
+	req->ecc.bytes = eccbytes;
+	req->ecc.strength = eccstrength;
+
+	if (req->ecc.ooboffset < 0)
+		req->ecc.ooboffset = req->oobsize - eccbytes;
+
+	return 0;
+}
+
+struct atmel_pmecc_user *
+atmel_pmecc_create_user(struct atmel_pmecc *pmecc,
+			struct atmel_pmecc_user_req *req)
+{
+	struct atmel_pmecc_user *user;
+	const struct atmel_pmecc_gf_tables *gf_tables;
+	int strength, size, ret;
+
+	ret = atmel_pmecc_prepare_user_req(pmecc, req);
+	if (ret)
+		return ERR_PTR(ret);
+
+	size = sizeof(*user);
+	size = ALIGN(size, sizeof(u16));
+	/* Reserve space for partial_syn, si and smu */
+	size += ((2 * req->ecc.strength) + 1) * sizeof(u16) *
+		(2 + req->ecc.strength + 2);
+	/* Reserve space for lmu. */
+	size += (req->ecc.strength + 1) * sizeof(u16);
+	/* Reserve space for mu, dmu and delta. */
+	size = ALIGN(size, sizeof(s32));
+	size += (req->ecc.strength + 1) * sizeof(s32) * 3;
+
+	user = kzalloc(size, GFP_KERNEL);
+	if (!user)
+		return ERR_PTR(-ENOMEM);
+
+	user->pmecc = pmecc;
+
+	user->partial_syn = (s16 *)PTR_ALIGN(user + 1, sizeof(u16));
+	user->si = user->partial_syn + ((2 * req->ecc.strength) + 1);
+	user->lmu = user->si + ((2 * req->ecc.strength) + 1);
+	user->smu = user->lmu + (req->ecc.strength + 1);
+	user->mu = (s32 *)PTR_ALIGN(user->smu +
+				    (((2 * req->ecc.strength) + 1) *
+				     (req->ecc.strength + 2)),
+				    sizeof(s32));
+	user->dmu = user->mu + req->ecc.strength + 1;
+	user->delta = user->dmu + req->ecc.strength + 1;
+
+	gf_tables = atmel_pmecc_get_gf_tables(req);
+	if (IS_ERR(gf_tables)) {
+		kfree(user);
+		return ERR_CAST(gf_tables);
+	}
+
+	user->gf_tables = gf_tables;
+
+	user->eccbytes = req->ecc.bytes / req->ecc.nsectors;
+
+	for (strength = 0; strength < pmecc->caps->nstrengths; strength++) {
+		if (pmecc->caps->strengths[strength] == req->ecc.strength)
+			break;
+	}
+
+	user->cache.cfg = PMECC_CFG_BCH_STRENGTH(strength) |
+			  PMECC_CFG_NSECTORS(req->ecc.nsectors);
+
+	if (req->ecc.sectorsize == 1024)
+		user->cache.cfg |= PMECC_CFG_SECTOR1024;
+
+	user->cache.sarea = req->oobsize - 1;
+	user->cache.saddr = req->ecc.ooboffset;
+	user->cache.eaddr = req->ecc.ooboffset + req->ecc.bytes - 1;
+
+	return user;
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_create_user);
+
+void atmel_pmecc_destroy_user(struct atmel_pmecc_user *user)
+{
+	kfree(user);
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_destroy_user);
+
+static int get_strength(struct atmel_pmecc_user *user)
+{
+	const int *strengths = user->pmecc->caps->strengths;
+
+	return strengths[user->cache.cfg & PMECC_CFG_BCH_STRENGTH_MASK];
+}
+
+static int get_sectorsize(struct atmel_pmecc_user *user)
+{
+	return user->cache.cfg & PMECC_LOOKUP_TABLE_SIZE_1024 ? 1024 : 512;
+}
+
+static void atmel_pmecc_gen_syndrome(struct atmel_pmecc_user *user, int sector)
+{
+	int strength = get_strength(user);
+	u32 value;
+	int i;
+
+	/* Fill odd syndromes */
+	for (i = 0; i < strength; i++) {
+		value = readl_relaxed(user->pmecc->regs.base +
+				      ATMEL_PMECC_REM(sector, i / 2));
+		if (i & 1)
+			value >>= 16;
+
+		user->partial_syn[(2 * i) + 1] = value;
+	}
+}
+
+static void atmel_pmecc_substitute(struct atmel_pmecc_user *user)
+{
+	int degree = get_sectorsize(user) == 512 ? 13 : 14;
+	int cw_len = BIT(degree) - 1;
+	int strength = get_strength(user);
+	s16 *alpha_to = user->gf_tables->alpha_to;
+	s16 *index_of = user->gf_tables->index_of;
+	s16 *partial_syn = user->partial_syn;
+	s16 *si;
+	int i, j;
+
+	/*
+	 * si[] is a table that holds the current syndrome value,
+	 * an element of that table belongs to the field
+	 */
+	si = user->si;
+
+	memset(&si[1], 0, sizeof(s16) * ((2 * strength) - 1));
+
+	/* Computation 2t syndromes based on S(x) */
+	/* Odd syndromes */
+	for (i = 1; i < 2 * strength; i += 2) {
+		for (j = 0; j < degree; j++) {
+			if (partial_syn[i] & BIT(j))
+				si[i] = alpha_to[i * j] ^ si[i];
+		}
+	}
+	/* Even syndrome = (Odd syndrome) ** 2 */
+	for (i = 2, j = 1; j <= strength; i = ++j << 1) {
+		if (si[j] == 0) {
+			si[i] = 0;
+		} else {
+			s16 tmp;
+
+			tmp = index_of[si[j]];
+			tmp = (tmp * 2) % cw_len;
+			si[i] = alpha_to[tmp];
+		}
+	}
+}
+
+static void atmel_pmecc_get_sigma(struct atmel_pmecc_user *user)
+{
+	s16 *lmu = user->lmu;
+	s16 *si = user->si;
+	s32 *mu = user->mu;
+	s32 *dmu = user->dmu;
+	s32 *delta = user->delta;
+	int degree = get_sectorsize(user) == 512 ? 13 : 14;
+	int cw_len = BIT(degree) - 1;
+	int strength = get_strength(user);
+	int num = 2 * strength + 1;
+	s16 *index_of = user->gf_tables->index_of;
+	s16 *alpha_to = user->gf_tables->alpha_to;
+	int i, j, k;
+	u32 dmu_0_count, tmp;
+	s16 *smu = user->smu;
+
+	/* index of largest delta */
+	int ro;
+	int largest;
+	int diff;
+
+	dmu_0_count = 0;
+
+	/* First Row */
+
+	/* Mu */
+	mu[0] = -1;
+
+	memset(smu, 0, sizeof(s16) * num);
+	smu[0] = 1;
+
+	/* discrepancy set to 1 */
+	dmu[0] = 1;
+	/* polynom order set to 0 */
+	lmu[0] = 0;
+	delta[0] = (mu[0] * 2 - lmu[0]) >> 1;
+
+	/* Second Row */
+
+	/* Mu */
+	mu[1] = 0;
+	/* Sigma(x) set to 1 */
+	memset(&smu[num], 0, sizeof(s16) * num);
+	smu[num] = 1;
+
+	/* discrepancy set to S1 */
+	dmu[1] = si[1];
+
+	/* polynom order set to 0 */
+	lmu[1] = 0;
+
+	delta[1] = (mu[1] * 2 - lmu[1]) >> 1;
+
+	/* Init the Sigma(x) last row */
+	memset(&smu[(strength + 1) * num], 0, sizeof(s16) * num);
+
+	for (i = 1; i <= strength; i++) {
+		mu[i + 1] = i << 1;
+		/* Begin Computing Sigma (Mu+1) and L(mu) */
+		/* check if discrepancy is set to 0 */
+		if (dmu[i] == 0) {
+			dmu_0_count++;
+
+			tmp = ((strength - (lmu[i] >> 1) - 1) / 2);
+			if ((strength - (lmu[i] >> 1) - 1) & 0x1)
+				tmp += 2;
+			else
+				tmp += 1;
+
+			if (dmu_0_count == tmp) {
+				for (j = 0; j <= (lmu[i] >> 1) + 1; j++)
+					smu[(strength + 1) * num + j] =
+							smu[i * num + j];
+
+				lmu[strength + 1] = lmu[i];
+				return;
+			}
+
+			/* copy polynom */
+			for (j = 0; j <= lmu[i] >> 1; j++)
+				smu[(i + 1) * num + j] = smu[i * num + j];
+
+			/* copy previous polynom order to the next */
+			lmu[i + 1] = lmu[i];
+		} else {
+			ro = 0;
+			largest = -1;
+			/* find largest delta with dmu != 0 */
+			for (j = 0; j < i; j++) {
+				if ((dmu[j]) && (delta[j] > largest)) {
+					largest = delta[j];
+					ro = j;
+				}
+			}
+
+			/* compute difference */
+			diff = (mu[i] - mu[ro]);
+
+			/* Compute degree of the new smu polynomial */
+			if ((lmu[i] >> 1) > ((lmu[ro] >> 1) + diff))
+				lmu[i + 1] = lmu[i];
+			else
+				lmu[i + 1] = ((lmu[ro] >> 1) + diff) * 2;
+
+			/* Init smu[i+1] with 0 */
+			for (k = 0; k < num; k++)
+				smu[(i + 1) * num + k] = 0;
+
+			/* Compute smu[i+1] */
+			for (k = 0; k <= lmu[ro] >> 1; k++) {
+				s16 a, b, c;
+
+				if (!(smu[ro * num + k] && dmu[i]))
+					continue;
+
+				a = index_of[dmu[i]];
+				b = index_of[dmu[ro]];
+				c = index_of[smu[ro * num + k]];
+				tmp = a + (cw_len - b) + c;
+				a = alpha_to[tmp % cw_len];
+				smu[(i + 1) * num + (k + diff)] = a;
+			}
+
+			for (k = 0; k <= lmu[i] >> 1; k++)
+				smu[(i + 1) * num + k] ^= smu[i * num + k];
+		}
+
+		/* End Computing Sigma (Mu+1) and L(mu) */
+		/* In either case compute delta */
+		delta[i + 1] = (mu[i + 1] * 2 - lmu[i + 1]) >> 1;
+
+		/* Do not compute discrepancy for the last iteration */
+		if (i >= strength)
+			continue;
+
+		for (k = 0; k <= (lmu[i + 1] >> 1); k++) {
+			tmp = 2 * (i - 1);
+			if (k == 0) {
+				dmu[i + 1] = si[tmp + 3];
+			} else if (smu[(i + 1) * num + k] && si[tmp + 3 - k]) {
+				s16 a, b, c;
+
+				a = index_of[smu[(i + 1) * num + k]];
+				b = si[2 * (i - 1) + 3 - k];
+				c = index_of[b];
+				tmp = a + c;
+				tmp %= cw_len;
+				dmu[i + 1] = alpha_to[tmp] ^ dmu[i + 1];
+			}
+		}
+	}
+}
+
+static int atmel_pmecc_err_location(struct atmel_pmecc_user *user)
+{
+	int sector_size = get_sectorsize(user);
+	int degree = sector_size == 512 ? 13 : 14;
+	struct atmel_pmecc *pmecc = user->pmecc;
+	int strength = get_strength(user);
+	int ret, roots_nbr, i, err_nbr = 0;
+	int num = (2 * strength) + 1;
+	s16 *smu = user->smu;
+	u32 val;
+
+	writel(PMERRLOC_DISABLE, pmecc->regs.errloc + ATMEL_PMERRLOC_ELDIS);
+
+	for (i = 0; i <= user->lmu[strength + 1] >> 1; i++) {
+		writel_relaxed(smu[(strength + 1) * num + i],
+			       pmecc->regs.errloc + ATMEL_PMERRLOC_SIGMA(i));
+		err_nbr++;
+	}
+
+	val = (err_nbr - 1) << 16;
+	if (sector_size == 1024)
+		val |= 1;
+
+	writel(val, pmecc->regs.errloc + ATMEL_PMERRLOC_ELCFG);
+	writel((sector_size * 8) + (degree * strength),
+	       pmecc->regs.errloc + ATMEL_PMERRLOC_ELEN);
+
+	ret = readl_relaxed_poll_timeout(pmecc->regs.errloc +
+					 ATMEL_PMERRLOC_ELISR,
+					 val, val & PMERRLOC_CALC_DONE, 0,
+					 PMECC_MAX_TIMEOUT_MS * 1000);
+	if (ret) {
+		dev_err(pmecc->dev,
+			"PMECC: Timeout to calculate error location.\n");
+		return ret;
+	}
+
+	roots_nbr = (val & PMERRLOC_ERR_NUM_MASK) >> 8;
+	/* Number of roots == degree of smu hence <= cap */
+	if (roots_nbr == user->lmu[strength + 1] >> 1)
+		return err_nbr - 1;
+
+	/*
+	 * Number of roots does not match the degree of smu
+	 * unable to correct error.
+	 */
+	return -EBADMSG;
+}
+
+int atmel_pmecc_correct_sector(struct atmel_pmecc_user *user, int sector,
+			       void *data, void *ecc)
+{
+	struct atmel_pmecc *pmecc = user->pmecc;
+	int sectorsize = get_sectorsize(user);
+	int eccbytes = user->eccbytes;
+	int i, nerrors;
+
+	if (!(user->isr & BIT(sector)))
+		return 0;
+
+	atmel_pmecc_gen_syndrome(user, sector);
+	atmel_pmecc_substitute(user);
+	atmel_pmecc_get_sigma(user);
+
+	nerrors = atmel_pmecc_err_location(user);
+	if (nerrors < 0)
+		return nerrors;
+
+	for (i = 0; i < nerrors; i++) {
+		const char *area;
+		int byte, bit;
+		u32 errpos;
+		u8 *ptr;
+
+		errpos = readl_relaxed(pmecc->regs.errloc +
+				ATMEL_PMERRLOC_EL(pmecc->caps->el_offset, i));
+		errpos--;
+
+		byte = errpos / 8;
+		bit = errpos % 8;
+
+		if (byte < sectorsize) {
+			ptr = data + byte;
+			area = "data";
+		} else if (byte < sectorsize + eccbytes) {
+			ptr = ecc + byte - sectorsize;
+			area = "ECC";
+		} else {
+			dev_dbg(pmecc->dev,
+				"Invalid errpos value (%d, max is %d)\n",
+				errpos, (sectorsize + eccbytes) * 8);
+			return -EINVAL;
+		}
+
+		dev_dbg(pmecc->dev,
+			"Bit flip in %s area, byte %d: 0x%02x -> 0x%02x\n",
+			area, byte, *ptr, (unsigned int)(*ptr ^ BIT(bit)));
+
+		*ptr ^= BIT(bit);
+	}
+
+	return nerrors;
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_correct_sector);
+
+bool atmel_pmecc_correct_erased_chunks(struct atmel_pmecc_user *user)
+{
+	return user->pmecc->caps->correct_erased_chunks;
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_correct_erased_chunks);
+
+void atmel_pmecc_get_generated_eccbytes(struct atmel_pmecc_user *user,
+					int sector, void *ecc)
+{
+	struct atmel_pmecc *pmecc = user->pmecc;
+	u8 *ptr = ecc;
+	int i;
+
+	for (i = 0; i < user->eccbytes; i++)
+		ptr[i] = readb_relaxed(pmecc->regs.base +
+				       ATMEL_PMECC_ECC(sector, i));
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_get_generated_eccbytes);
+
+void atmel_pmecc_reset(struct atmel_pmecc *pmecc)
+{
+	writel(PMECC_CTRL_RST, pmecc->regs.base + ATMEL_PMECC_CTRL);
+	writel(PMECC_CTRL_DISABLE, pmecc->regs.base + ATMEL_PMECC_CTRL);
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_reset);
+
+int atmel_pmecc_enable(struct atmel_pmecc_user *user, int op)
+{
+	struct atmel_pmecc *pmecc = user->pmecc;
+	u32 cfg;
+
+	if (op != NAND_ECC_READ && op != NAND_ECC_WRITE) {
+		dev_err(pmecc->dev, "Bad ECC operation!");
+		return -EINVAL;
+	}
+
+	mutex_lock(&user->pmecc->lock);
+
+	cfg = user->cache.cfg;
+	if (op == NAND_ECC_WRITE)
+		cfg |= PMECC_CFG_WRITE_OP;
+	else
+		cfg |= PMECC_CFG_AUTO_ENABLE;
+
+	writel(cfg, pmecc->regs.base + ATMEL_PMECC_CFG);
+	writel(user->cache.sarea, pmecc->regs.base + ATMEL_PMECC_SAREA);
+	writel(user->cache.saddr, pmecc->regs.base + ATMEL_PMECC_SADDR);
+	writel(user->cache.eaddr, pmecc->regs.base + ATMEL_PMECC_EADDR);
+
+	writel(PMECC_CTRL_ENABLE, pmecc->regs.base + ATMEL_PMECC_CTRL);
+	writel(PMECC_CTRL_DATA, pmecc->regs.base + ATMEL_PMECC_CTRL);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_enable);
+
+void atmel_pmecc_disable(struct atmel_pmecc_user *user)
+{
+	atmel_pmecc_reset(user->pmecc);
+	mutex_unlock(&user->pmecc->lock);
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_disable);
+
+int atmel_pmecc_wait_rdy(struct atmel_pmecc_user *user)
+{
+	struct atmel_pmecc *pmecc = user->pmecc;
+	u32 status;
+	int ret;
+
+	ret = readl_relaxed_poll_timeout(pmecc->regs.base +
+					 ATMEL_PMECC_SR,
+					 status, !(status & PMECC_SR_BUSY), 0,
+					 PMECC_MAX_TIMEOUT_MS * 1000);
+	if (ret) {
+		dev_err(pmecc->dev,
+			"Timeout while waiting for PMECC ready.\n");
+		return ret;
+	}
+
+	user->isr = readl_relaxed(pmecc->regs.base + ATMEL_PMECC_ISR);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(atmel_pmecc_wait_rdy);
+
+static struct atmel_pmecc *atmel_pmecc_create(struct platform_device *pdev,
+					const struct atmel_pmecc_caps *caps,
+					int pmecc_res_idx, int errloc_res_idx)
+{
+	struct device *dev = &pdev->dev;
+	struct atmel_pmecc *pmecc;
+	struct resource *res;
+
+	pmecc = devm_kzalloc(dev, sizeof(*pmecc), GFP_KERNEL);
+	if (!pmecc)
+		return ERR_PTR(-ENOMEM);
+
+	pmecc->caps = caps;
+	pmecc->dev = dev;
+	mutex_init(&pmecc->lock);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, pmecc_res_idx);
+	pmecc->regs.base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pmecc->regs.base))
+		return ERR_CAST(pmecc->regs.base);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, errloc_res_idx);
+	pmecc->regs.errloc = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pmecc->regs.errloc))
+		return ERR_CAST(pmecc->regs.errloc);
+
+	/* Disable all interrupts before registering the PMECC handler. */
+	writel(0xffffffff, pmecc->regs.base + ATMEL_PMECC_IDR);
+	atmel_pmecc_reset(pmecc);
+
+	return pmecc;
+}
+
+static void devm_atmel_pmecc_put(struct device *dev, void *res)
+{
+	struct atmel_pmecc **pmecc = res;
+
+	put_device((*pmecc)->dev);
+}
+
+static struct atmel_pmecc *atmel_pmecc_get_by_node(struct device *userdev,
+						   struct device_node *np)
+{
+	struct platform_device *pdev;
+	struct atmel_pmecc *pmecc, **ptr;
+
+	pdev = of_find_device_by_node(np);
+	if (!pdev || !platform_get_drvdata(pdev))
+		return ERR_PTR(-EPROBE_DEFER);
+
+	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	get_device(&pdev->dev);
+	pmecc = platform_get_drvdata(pdev);
+
+	*ptr = pmecc;
+
+	devres_add(userdev, ptr);
+
+	return pmecc;
+}
+
+static const int atmel_pmecc_strengths[] = { 2, 4, 8, 12, 24, 32 };
+
+static struct atmel_pmecc_caps at91sam9g45_caps = {
+	.strengths = atmel_pmecc_strengths,
+	.nstrengths = 5,
+	.el_offset = 0x8c,
+};
+
+static struct atmel_pmecc_caps sama5d4_caps = {
+	.strengths = atmel_pmecc_strengths,
+	.nstrengths = 5,
+	.el_offset = 0x8c,
+	.correct_erased_chunks = true,
+};
+
+static struct atmel_pmecc_caps sama5d2_caps = {
+	.strengths = atmel_pmecc_strengths,
+	.nstrengths = 6,
+	.el_offset = 0xac,
+	.correct_erased_chunks = true,
+};
+
+static const struct of_device_id atmel_pmecc_legacy_match[] = {
+	{ .compatible = "atmel,sama5d4-nand", &sama5d4_caps },
+	{ .compatible = "atmel,sama5d2-nand", &sama5d2_caps },
+	{ /* sentinel */ }
+};
+
+struct atmel_pmecc *devm_atmel_pmecc_get(struct device *userdev)
+{
+	struct atmel_pmecc *pmecc;
+	struct device_node *np;
+
+	if (!userdev)
+		return ERR_PTR(-EINVAL);
+
+	if (!userdev->of_node)
+		return NULL;
+
+	np = of_parse_phandle(userdev->of_node, "ecc-engine", 0);
+	if (np) {
+		pmecc = atmel_pmecc_get_by_node(userdev, np);
+		of_node_put(np);
+	} else {
+		/*
+		 * Support old DT bindings: in this case the PMECC iomem
+		 * resources are directly defined in the user pdev at position
+		 * 1 and 2. Extract all relevant information from there.
+		 */
+		struct platform_device *pdev = to_platform_device(userdev);
+		const struct atmel_pmecc_caps *caps;
+		const struct of_device_id *match;
+
+		/* No PMECC engine available. */
+		if (!of_property_read_bool(userdev->of_node,
+					   "atmel,has-pmecc"))
+			return NULL;
+
+		caps = &at91sam9g45_caps;
+
+		/* Find the caps associated to the NAND dev node. */
+		match = of_match_node(atmel_pmecc_legacy_match,
+				      userdev->of_node);
+		if (match && match->data)
+			caps = match->data;
+
+		pmecc = atmel_pmecc_create(pdev, caps, 1, 2);
+	}
+
+	return pmecc;
+}
+EXPORT_SYMBOL(devm_atmel_pmecc_get);
+
+static const struct of_device_id atmel_pmecc_match[] = {
+	{ .compatible = "atmel,at91sam9g45-pmecc", &at91sam9g45_caps },
+	{ .compatible = "atmel,sama5d4-pmecc", &sama5d4_caps },
+	{ .compatible = "atmel,sama5d2-pmecc", &sama5d2_caps },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_pmecc_match);
+
+static int atmel_pmecc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct atmel_pmecc_caps *caps;
+	struct atmel_pmecc *pmecc;
+
+	caps = of_device_get_match_data(&pdev->dev);
+	if (!caps) {
+		dev_err(dev, "Invalid caps\n");
+		return -EINVAL;
+	}
+
+	pmecc = atmel_pmecc_create(pdev, caps, 0, 1);
+	if (IS_ERR(pmecc))
+		return PTR_ERR(pmecc);
+
+	platform_set_drvdata(pdev, pmecc);
+
+	return 0;
+}
+
+static struct platform_driver atmel_pmecc_driver = {
+	.driver = {
+		.name = "atmel-pmecc",
+		.of_match_table = of_match_ptr(atmel_pmecc_match),
+	},
+	.probe = atmel_pmecc_probe,
+};
+module_platform_driver(atmel_pmecc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
+MODULE_DESCRIPTION("PMECC engine driver");
+MODULE_ALIAS("platform:atmel_pmecc");