This commit introduces support for exposing otp regions
in mtd flash devices as nvmem providers, allowing them to provide
information such as serial numbers, calibration data or
product ids.
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Brian Norris <computersforpeace@xxxxxxxxx>
Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Moritz Fischer <moritz.fischer@xxxxxxxxx>
---
drivers/mtd/Kconfig | 8 ++++
drivers/mtd/Makefile | 1 +
drivers/mtd/mtdcore.c | 35 ++++++++++++++
drivers/mtd/mtdcore.h | 1 +
drivers/mtd/mtdnvmem.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/mtdnvmem.h | 25 ++++++++++
drivers/mtd/mtdpart.c | 112 +++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/ofpart.c | 102 +++++++++++++++++++++++++++++++++++++++
8 files changed, 411 insertions(+)
create mode 100644 drivers/mtd/mtdnvmem.c
create mode 100644 drivers/mtd/mtdnvmem.h
diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index e83a279..4d99b64 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -309,6 +309,14 @@ config MTD_SWAP
The driver provides wear leveling by storing erase counter into the
OOB.
+config MTD_NVMEM
+ tristate "Expose OTP regions as NVMEM providers"
+ depends on MTD && NVMEM
+ help
+ Allows exposing OTP regions in mtd devices via nvmem.
+ This is useful for storing information like calibration data,
+ serial numbers, or mac addresses.
+
config MTD_PARTITIONED_MASTER
bool "Retain master device when partitioned"
default n
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 99bb9a1..f62f50b 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -26,6 +26,7 @@ obj-$(CONFIG_SSFDC) += ssfdc.o
obj-$(CONFIG_SM_FTL) += sm_ftl.o
obj-$(CONFIG_MTD_OOPS) += mtdoops.o
obj-$(CONFIG_MTD_SWAP) += mtdswap.o
+obj-$(CONFIG_MTD_NVMEM) += mtdnvmem.o
nftl-objs := nftlcore.o nftlmount.o
inftl-objs := inftlcore.o inftlmount.o
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 8965ffa..9f187bc 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -46,6 +46,7 @@
#include <linux/mtd/partitions.h>
#include "mtdcore.h"
+#include "mtdnvmem.h"
static struct backing_dev_info mtd_bdi = {
};
@@ -566,6 +567,30 @@ static int mtd_add_device_partitions(struct mtd_info *mtd,
return 0;
}
+#ifdef CONFIG_MTD_NVMEM
+static int mtd_add_device_otp_regions(struct mtd_info *mtd,
+ struct mtd_partitions *parts)
+{
+ const struct mtd_partition *real_parts = parts->parts;
+ int nbparts = parts->nr_parts;
+ int ret;
+
+ if (nbparts > 0) {
+ ret = add_otp_regions(mtd, real_parts, nbparts);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+#else
+static int mtd_add_device_otp_regions(struct mtd_info *mtd,
+ struct mtd_partitions *parts)
+{
+ return 0;
+}
+#endif
+
/*
* Set a few defaults based on the parent devices, if not provided by the
* driver
@@ -582,6 +607,8 @@ static void mtd_set_dev_defaults(struct mtd_info *mtd)
}
}
+static const char const *otp_types[] = {"ofotp", NULL};
+
/**
* mtd_device_parse_register - parse partitions and register an MTD device.
*
@@ -642,6 +669,14 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,
if (ret)
goto out;
+ ret = parse_mtd_partitions(mtd, otp_types, &parsed, parser_data);
+ if (ret)
+ goto out;
+
+ ret = mtd_add_device_otp_regions(mtd, &parsed);
+ if (ret)
+ goto out;
+
/*
* FIXME: some drivers unfortunately call this function more than once.
* So we have to check if we've already assigned the reboot notifier.
diff --git a/drivers/mtd/mtdcore.h b/drivers/mtd/mtdcore.h
index 55fdb8e..11ccb90 100644
--- a/drivers/mtd/mtdcore.h
+++ b/drivers/mtd/mtdcore.h
@@ -9,6 +9,7 @@ struct mtd_info *__mtd_next_device(int i);
int add_mtd_device(struct mtd_info *mtd);
int del_mtd_device(struct mtd_info *mtd);
int add_mtd_partitions(struct mtd_info *, const struct mtd_partition *, int);
+int add_otp_regions(struct mtd_info *, const struct mtd_partition *, int);
int del_mtd_partitions(struct mtd_info *);
struct mtd_partitions;
diff --git a/drivers/mtd/mtdnvmem.c b/drivers/mtd/mtdnvmem.c
new file mode 100644
index 0000000..e99a95e
--- /dev/null
+++ b/drivers/mtd/mtdnvmem.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (c) 2016, National Instruments Corp.
+ *
+ * Generic NVMEM support for OTP regions in MTD devices
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+
+struct mtd_nvmem {
+ struct mtd_info *info;
+ struct nvmem_device *dev;
+ struct regmap *regmap;
+};
+
+static int mtd_otp_regmap_read(void *context, const void *reg, size_t reg_size,
+ void *val, size_t val_size)
+{
+ struct mtd_info *info = context;
+ const u8 *offset = reg;
+ int err;
+ size_t retlen;
+
+ if (reg_size != 1)
+ return -EINVAL;
+
+ err = mtd_read_user_prot_reg(info, *offset, val_size > info->size
+ ? info->size : val_size, &retlen,
+ (u_char *)val);
+
+ return 0;
+}
+
+static int mtd_otp_regmap_write(void *context, const void *data, size_t count)
+{
+ /* Not implemented */
+ return 0;
+}
+
+static const struct regmap_bus mtd_otp_bus = {
+ .read = mtd_otp_regmap_read,
+ .write = mtd_otp_regmap_write,
+ .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
+ .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
+};
+
+static bool mtd_otp_nvmem_writeable_reg(struct device *dev, unsigned int reg)
+{
+ return false;
+}
+
+static struct regmap_config mtd_otp_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .reg_stride = 1,
+ .writeable_reg = mtd_otp_nvmem_writeable_reg,
+ .name = "mtd-otp",
+};
+
+static struct nvmem_config mtd_otp_nvmem_config = {
+ .read_only = true,
+ .owner = THIS_MODULE,
+};
+
+struct mtd_nvmem *mtd_otp_nvmem_register(struct mtd_info *info)
+{
+ struct mtd_nvmem *nvmem;
+ struct device *dev = &info->dev;
+
+ nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL);
+ if (!nvmem)
+ return ERR_PTR(-ENOMEM);
+
+ mtd_otp_regmap_config.max_register = info->size;
+
+ nvmem->regmap = regmap_init(dev, &mtd_otp_bus, info,
+ &mtd_otp_regmap_config);
+ if (IS_ERR(nvmem->regmap)) {
+ dev_err(dev, "regmap init failed");
+ goto out_free;
+ }
+
+ mtd_otp_nvmem_config.dev = dev;
+ mtd_otp_nvmem_config.name = info->name;
+
+ nvmem->dev = nvmem_register(&mtd_otp_nvmem_config);
+
+ if (!nvmem->dev) {
+ dev_err(dev, "failed to register nvmem");
+ goto out_regmap;
+ }
+
+ return nvmem;
+
+out_regmap:
+ regmap_exit(nvmem->regmap);
+
+out_free:
+ kfree(nvmem);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(mtd_otp_nvmem_register);
+
+void mtd_otp_nvmem_remove(struct mtd_nvmem *nvmem)
+{
+ nvmem_unregister(nvmem->dev);
+ regmap_exit(nvmem->regmap);
+ kfree(nvmem);
+}
+EXPORT_SYMBOL_GPL(mtd_otp_nvmem_remove);
diff --git a/drivers/mtd/mtdnvmem.h b/drivers/mtd/mtdnvmem.h
new file mode 100644
index 0000000..1003c5f
--- /dev/null
+++ b/drivers/mtd/mtdnvmem.h
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2016, National Instruments Corp.
+ *
+ * Generic NVMEM support for OTP regions in MTD devices
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef MTDNVMEM_H
+#define MTDNVMEM_H
+
+struct mtd_nvmem;
+
+struct mtd_nvmem *mtd_otp_nvmem_register(struct mtd_info *info);
+
+void mtd_otp_nvmem_remove(struct mtd_nvmem *mem);
+
+#endif /* MTDNVMEM_H */
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
index 6ef118d..7acf82bf 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -33,6 +33,7 @@
#include <linux/kconfig.h>
#include "mtdcore.h"
+#include "mtdnvmem.h"
/* Our partition linked list */
static LIST_HEAD(mtd_partitions);
@@ -44,6 +45,7 @@ struct mtd_part {
struct mtd_info *master;
uint64_t offset;
struct list_head list;
+ struct mtd_nvmem *nv;
};
/*
@@ -319,6 +321,10 @@ static int part_block_markbad(struct mtd_info *mtd, loff_t ofs)
static inline void free_partition(struct mtd_part *p)
{
+#ifdef CONFIG_MTD_NVMEM
+ if (p->nv)
+ mtd_otp_nvmem_remove(p->nv);
+#endif
kfree(p->mtd.name);
kfree(p);
}
@@ -349,6 +355,72 @@ int del_mtd_partitions(struct mtd_info *master)
return err;
}
+#ifdef CONFIG_MTD_NVMEM
+static struct mtd_part *allocate_otp_region(struct mtd_info *master,
+ const struct mtd_partition *part,
+ int partno, uint64_t cur_offset)
+{
+ struct mtd_part *slave;
+ char *name;
+
+ /* allocate the partition structure */
+ slave = kzalloc(sizeof(*slave), GFP_KERNEL);
+ name = kstrdup(part->name, GFP_KERNEL);
+ if (!name || !slave) {
+ pr_err("memory allocation error while creating partitions for \"%s\"\n",
+ master->name);
+ kfree(name);
+ kfree(slave);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ /* set up the MTD object for this partition */
+ slave->mtd.type = master->type;
+ slave->mtd.flags = master->flags & ~part->mask_flags;
+ slave->mtd.size = part->size;
+ slave->mtd.writesize = 1;
+ slave->mtd.writebufsize = 1;
+ slave->mtd.erasesize = 1;
+ slave->mtd.oobsize = 0;
+ slave->mtd.oobavail = 0;
+ slave->mtd.subpage_sft = master->subpage_sft;
+
+ slave->mtd.name = name;
+ slave->mtd.owner = master->owner;
+ slave->mtd.dev.of_node = part->node;
+
+ if (master->_read_user_prot_reg)
+ slave->mtd._read_user_prot_reg = part_read_user_prot_reg;
+ if (master->_read_fact_prot_reg)
+ slave->mtd._read_fact_prot_reg = part_read_fact_prot_reg;
+ if (master->_write_user_prot_reg)
+ slave->mtd._write_user_prot_reg = part_write_user_prot_reg;
+ if (master->_lock_user_prot_reg)
+ slave->mtd._lock_user_prot_reg = part_lock_user_prot_reg;
+ if (master->_get_user_prot_info)
+ slave->mtd._get_user_prot_info = part_get_user_prot_info;
+ if (master->_get_fact_prot_info)
+ slave->mtd._get_fact_prot_info = part_get_fact_prot_info;
+
+ if (!partno && !master->dev.class && master->_suspend &&
+ master->_resume) {
+ slave->mtd._suspend = part_suspend;
+ slave->mtd._resume = part_resume;
+ }
+
+ slave->master = master;
+ slave->offset = part->offset;
+ slave->mtd.size = part->size;
+
+ pr_notice("0x%012llx-0x%012llx : \"%s\"\n",
+ (unsigned long long)slave->offset,
+ (unsigned long long)(slave->offset + slave->mtd.size),
+ slave->mtd.name);
+
+ return slave;
+}
+#endif
+
static struct mtd_part *allocate_partition(struct mtd_info *master,
const struct mtd_partition *part, int partno,
uint64_t cur_offset)
@@ -682,6 +754,46 @@ int add_mtd_partitions(struct mtd_info *master,
return 0;
}
+#ifdef CONFIG_MTD_NVMEM
+int add_otp_regions(struct mtd_info *master,
+ const struct mtd_partition *parts, int nbparts)
+{
+ struct mtd_part *slave;
+ u64 cur_offset = 0;
+ int i;
+
+ pr_notice("Creating %d MTD OTP region(s) on \"%s\":\n", nbparts,
+ master->name);
+
+ for (i = 0; i < nbparts; i++) {
+ slave = allocate_otp_region(master, parts + i, i, cur_offset);
+ if (IS_ERR(slave)) {
+ del_mtd_partitions(master);
+ return PTR_ERR(slave);
+ }
+
+ mutex_lock(&mtd_partitions_mutex);
+ list_add(&slave->list, &mtd_partitions);
+ mutex_unlock(&mtd_partitions_mutex);
+
+ add_mtd_device(&slave->mtd);
+ mtd_add_partition_attrs(slave);
+
+ slave->nv = mtd_otp_nvmem_register(&slave->mtd);
+
+ cur_offset = slave->offset + slave->mtd.size;
+ }
+
+ return 0;
+}
+#else
+int add_otp_regions(struct mtd_info *master,
+ const struct mtd_partition *parts, int nbparts)
+{
+ return 0;
+}
+#endif
+
static DEFINE_SPINLOCK(part_parser_lock);
static LIST_HEAD(part_parsers);
diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
index 9a68bff..3a0d14d 100644
--- a/drivers/mtd/ofpart.c
+++ b/drivers/mtd/ofpart.c
@@ -145,6 +145,106 @@ static struct mtd_part_parser ofpart_parser = {
.name = "ofpart",
};
+static int parse_ofotp_partitions(struct mtd_info *master,
+ const struct mtd_partition **pparts,
+ struct mtd_part_parser_data *data)
+{
+ struct mtd_partition *parts;
+ struct device_node *mtd_node;
+ struct device_node *ofpart_node;
+ const char *partname;
+ struct device_node *pp;
+ int nr_parts, i, ret = 0;
+
+ /* Pull of_node from the master device node */
+ mtd_node = mtd_get_of_node(master);
+ if (!mtd_node)
+ return 0;
+
+ ofpart_node = of_get_child_by_name(mtd_node, "otp-partitions");
+ if (!ofpart_node) {
+ /*
+ * We might get here even when ofpart isn't used at all (e.g.,
+ * when using another parser), so don't be louder than
+ * KERN_DEBUG
+ */
+ pr_debug("%s: 'otp-partitions' subnode not found on %s\n",
+ master->name, mtd_node->full_name);
+ return 0;
+ } else if (!of_device_is_compatible(ofpart_node, "fixed-partitions")) {
+ /* The 'partitions' subnode might be used by another parser */
+ return 0;
+ }
+
+ /* First count the subnodes */
+ nr_parts = 0;
+ for_each_child_of_node(ofpart_node, pp)
+ nr_parts++;
+
+ if (nr_parts == 0)
+ return 0;
+
+ parts = kcalloc(nr_parts, sizeof(*parts), GFP_KERNEL);
+ if (!parts)
+ return -ENOMEM;
+
+ i = 0;
+ for_each_child_of_node(ofpart_node, pp) {
+ const __be32 *reg;
+ int len;
+ int a_cells, s_cells;
+
+ reg = of_get_property(pp, "reg", &len);
+ if (!reg) {
+ nr_parts--;
+ continue;
+ }
+
+ a_cells = of_n_addr_cells(pp);
+ s_cells = of_n_size_cells(pp);
+ if (len / 4 != a_cells + s_cells) {
+ pr_debug("%s: ofpart partition %s (%s) error parsing reg property.\n",
+ master->name, pp->full_name,
+ mtd_node->full_name);
+ goto ofpart_fail;
+ }
+
+ parts[i].offset = of_read_number(reg, a_cells);
+ parts[i].size = of_read_number(reg + a_cells, s_cells);
+ parts[i].node = pp;
+
+ partname = of_get_property(pp, "label", &len);
+ if (!partname)
+ partname = of_get_property(pp, "name", &len);
+ parts[i].name = partname;
+
+ if (of_get_property(pp, "read-only", &len))
+ parts[i].mask_flags |= MTD_WRITEABLE;
+
+ i++;
+ }
+
+ if (!nr_parts)
+ goto ofpart_none;
+
+ *pparts = parts;
+ return nr_parts;
+
+ofpart_fail:
+ pr_err("%s: error parsing ofotp partition %s (%s)\n",
+ master->name, pp->full_name, mtd_node->full_name);
+ ret = -EINVAL;
+ofpart_none:
+ of_node_put(pp);
+ kfree(parts);
+ return ret;
+}
+
+static struct mtd_part_parser ofotp_parser = {
+ .parse_fn = parse_ofotp_partitions,
+ .name = "ofotp",
+};
+
static int parse_ofoldpart_partitions(struct mtd_info *master,
const struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
@@ -210,6 +310,7 @@ static int __init ofpart_parser_init(void)
{
register_mtd_parser(&ofpart_parser);
register_mtd_parser(&ofoldpart_parser);
+ register_mtd_parser(&ofotp_parser);
return 0;
}
@@ -217,6 +318,7 @@ static void __exit ofpart_parser_exit(void)
{
deregister_mtd_parser(&ofpart_parser);
deregister_mtd_parser(&ofoldpart_parser);
+ deregister_mtd_parser(&ofotp_parser);
}
module_init(ofpart_parser_init);
--
2.5.5
--
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