1 files changed, 86 insertions, 62 deletions

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 97ac219c082e..76b4264936ff 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -41,6 +41,7 @@
 #include <linux/reboot.h>
 #include <linux/leds.h>
 #include <linux/debugfs.h>
+#include <linux/nvmem-provider.h>
 
 #include <linux/mtd/mtd.h>
 #include <linux/mtd/partitions.h>
@@ -154,7 +155,6 @@ static ssize_t mtd_flags_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "0x%lx\n", (unsigned long)mtd->flags);
-
 }
 static DEVICE_ATTR(flags, S_IRUGO, mtd_flags_show, NULL);
 
@@ -165,7 +165,6 @@ static ssize_t mtd_size_show(struct device *dev,
 
 	return snprintf(buf, PAGE_SIZE, "%llu\n",
 		(unsigned long long)mtd->size);
-
 }
 static DEVICE_ATTR(size, S_IRUGO, mtd_size_show, NULL);
 
@@ -175,7 +174,6 @@ static ssize_t mtd_erasesize_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->erasesize);
-
 }
 static DEVICE_ATTR(erasesize, S_IRUGO, mtd_erasesize_show, NULL);
 
@@ -185,7 +183,6 @@ static ssize_t mtd_writesize_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->writesize);
-
 }
 static DEVICE_ATTR(writesize, S_IRUGO, mtd_writesize_show, NULL);
 
@@ -196,7 +193,6 @@ static ssize_t mtd_subpagesize_show(struct device *dev,
 	unsigned int subpagesize = mtd->writesize >> mtd->subpage_sft;
 
 	return snprintf(buf, PAGE_SIZE, "%u\n", subpagesize);
-
 }
 static DEVICE_ATTR(subpagesize, S_IRUGO, mtd_subpagesize_show, NULL);
 
@@ -206,7 +202,6 @@ static ssize_t mtd_oobsize_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "%lu\n", (unsigned long)mtd->oobsize);
-
 }
 static DEVICE_ATTR(oobsize, S_IRUGO, mtd_oobsize_show, NULL);
 
@@ -225,7 +220,6 @@ static ssize_t mtd_numeraseregions_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "%u\n", mtd->numeraseregions);
-
 }
 static DEVICE_ATTR(numeraseregions, S_IRUGO, mtd_numeraseregions_show,
 	NULL);
@@ -236,7 +230,6 @@ static ssize_t mtd_name_show(struct device *dev,
 	struct mtd_info *mtd = dev_get_drvdata(dev);
 
 	return snprintf(buf, PAGE_SIZE, "%s\n", mtd->name);
-
 }
 static DEVICE_ATTR(name, S_IRUGO, mtd_name_show, NULL);
 
@@ -488,6 +481,51 @@ int mtd_pairing_groups(struct mtd_info *mtd)
 }
 EXPORT_SYMBOL_GPL(mtd_pairing_groups);
 
+static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
+			      void *val, size_t bytes)
+{
+	struct mtd_info *mtd = priv;
+	size_t retlen;
+	int err;
+
+	err = mtd_read(mtd, offset, bytes, &retlen, val);
+	if (err && err != -EUCLEAN)
+		return err;
+
+	return retlen == bytes ? 0 : -EIO;
+}
+
+static int mtd_nvmem_add(struct mtd_info *mtd)
+{
+	struct nvmem_config config = {};
+
+	config.id = -1;
+	config.dev = &mtd->dev;
+	config.name = mtd->name;
+	config.owner = THIS_MODULE;
+	config.reg_read = mtd_nvmem_reg_read;
+	config.size = mtd->size;
+	config.word_size = 1;
+	config.stride = 1;
+	config.read_only = true;
+	config.root_only = true;
+	config.no_of_node = true;
+	config.priv = mtd;
+
+	mtd->nvmem = nvmem_register(&config);
+	if (IS_ERR(mtd->nvmem)) {
+		/* Just ignore if there is no NVMEM support in the kernel */
+		if (PTR_ERR(mtd->nvmem) == -EOPNOTSUPP) {
+			mtd->nvmem = NULL;
+		} else {
+			dev_err(&mtd->dev, "Failed to register NVMEM device\n");
+			return PTR_ERR(mtd->nvmem);
+		}
+	}
+
+	return 0;
+}
+
 static struct dentry *dfs_dir_mtd;
 
 /**
@@ -514,6 +552,14 @@ int add_mtd_device(struct mtd_info *mtd)
 
 	BUG_ON(mtd->writesize == 0);
 
+	/*
+	 * MTD drivers should implement ->_{write,read}() or
+	 * ->_{write,read}_oob(), but not both.
+	 */
+	if (WARN_ON((mtd->_write && mtd->_write_oob) ||
+		    (mtd->_read && mtd->_read_oob)))
+		return -EINVAL;
+
 	if (WARN_ON((!mtd->erasesize || !mtd->_erase) &&
 		    !(mtd->flags & MTD_NO_ERASE)))
 		return -EINVAL;
@@ -570,6 +616,11 @@ int add_mtd_device(struct mtd_info *mtd)
 	if (error)
 		goto fail_added;
 
+	/* Add the nvmem provider */
+	error = mtd_nvmem_add(mtd);
+	if (error)
+		goto fail_nvmem_add;
+
 	if (!IS_ERR_OR_NULL(dfs_dir_mtd)) {
 		mtd->dbg.dfs_dir = debugfs_create_dir(dev_name(&mtd->dev), dfs_dir_mtd);
 		if (IS_ERR_OR_NULL(mtd->dbg.dfs_dir)) {
@@ -595,6 +646,8 @@ int add_mtd_device(struct mtd_info *mtd)
 	__module_get(THIS_MODULE);
 	return 0;
 
+fail_nvmem_add:
+	device_unregister(&mtd->dev);
 fail_added:
 	of_node_put(mtd_get_of_node(mtd));
 	idr_remove(&mtd_idr, i);
@@ -637,6 +690,10 @@ int del_mtd_device(struct mtd_info *mtd)
 		       mtd->index, mtd->name, mtd->usecount);
 		ret = -EBUSY;
 	} else {
+		/* Try to remove the NVMEM provider */
+		if (mtd->nvmem)
+			nvmem_unregister(mtd->nvmem);
+
 		device_unregister(&mtd->dev);
 
 		idr_remove(&mtd_idr, mtd->index);
@@ -665,6 +722,8 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd)
 	} else {
 		pr_debug("mtd device won't show a device symlink in sysfs\n");
 	}
+
+	mtd->orig_flags = mtd->flags;
 }
 
 /**
@@ -1031,67 +1090,32 @@ EXPORT_SYMBOL_GPL(mtd_get_unmapped_area);
 int mtd_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
 	     u_char *buf)
 {
-	int ret_code;
-	*retlen = 0;
-	if (from < 0 || from >= mtd->size || len > mtd->size - from)
-		return -EINVAL;
-	if (!len)
-		return 0;
+	struct mtd_oob_ops ops = {
+		.len = len,
+		.datbuf = buf,
+	};
+	int ret;
 
-	ledtrig_mtd_activity();
-	/*
-	 * In the absence of an error, drivers return a non-negative integer
-	 * representing the maximum number of bitflips that were corrected on
-	 * any one ecc region (if applicable; zero otherwise).
-	 */
-	if (mtd->_read) {
-		ret_code = mtd->_read(mtd, from, len, retlen, buf);
-	} else if (mtd->_read_oob) {
-		struct mtd_oob_ops ops = {
-			.len = len,
-			.datbuf = buf,
-		};
-
-		ret_code = mtd->_read_oob(mtd, from, &ops);
-		*retlen = ops.retlen;
-	} else {
-		return -ENOTSUPP;
-	}
+	ret = mtd_read_oob(mtd, from, &ops);
+	*retlen = ops.retlen;
 
-	if (unlikely(ret_code < 0))
-		return ret_code;
-	if (mtd->ecc_strength == 0)
-		return 0;	/* device lacks ecc */
-	return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_read);
 
 int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
 	      const u_char *buf)
 {
-	*retlen = 0;
-	if (to < 0 || to >= mtd->size || len > mtd->size - to)
-		return -EINVAL;
-	if ((!mtd->_write && !mtd->_write_oob) ||
-	    !(mtd->flags & MTD_WRITEABLE))
-		return -EROFS;
-	if (!len)
-		return 0;
-	ledtrig_mtd_activity();
+	struct mtd_oob_ops ops = {
+		.len = len,
+		.datbuf = (u8 *)buf,
+	};
+	int ret;
 
-	if (!mtd->_write) {
-		struct mtd_oob_ops ops = {
-			.len = len,
-			.datbuf = (u8 *)buf,
-		};
-		int ret;
+	ret = mtd_write_oob(mtd, to, &ops);
+	*retlen = ops.retlen;
 
-		ret = mtd->_write_oob(mtd, to, &ops);
-		*retlen = ops.retlen;
-		return ret;
-	}
-
-	return mtd->_write(mtd, to, len, retlen, buf);
+	return ret;
 }
 EXPORT_SYMBOL_GPL(mtd_write);
 
@@ -1136,13 +1160,13 @@ static int mtd_check_oob_ops(struct mtd_info *mtd, loff_t offs,
 		return -EINVAL;
 
 	if (ops->ooblen) {
-		u64 maxooblen;
+		size_t maxooblen;
 
 		if (ops->ooboffs >= mtd_oobavail(mtd, ops))
 			return -EINVAL;
 
-		maxooblen = ((mtd_div_by_ws(mtd->size, mtd) -
-			      mtd_div_by_ws(offs, mtd)) *
+		maxooblen = ((size_t)(mtd_div_by_ws(mtd->size, mtd) -
+				      mtd_div_by_ws(offs, mtd)) *
 			     mtd_oobavail(mtd, ops)) - ops->ooboffs;
 		if (ops->ooblen > maxooblen)
 			return -EINVAL;