[PATCH v4 00/20] nvmem: core: introduce NVMEM layouts

[PATCH v4 00/20] nvmem: core: introduce NVMEM layouts

[Michael Walle]

This is now the third attempt to fetch the MAC addresses from the VPD
for the Kontron sl28 boards. Previous discussions can be found here:
https://lore.kernel.org/lkml/20211228142549.1275412-1-michael@walle.cc/


NVMEM cells are typically added by board code or by the devicetree. But
as the cells get more complex, there is (valid) push back from the
devicetree maintainers to not put that handling in the devicetree.

Therefore, introduce NVMEM layouts. They operate on the NVMEM device and
can add cells during runtime. That way it is possible to add more complex
cells than it is possible right now with the offset/length/bits
description in the device tree. For example, you can have post processing
for individual cells (think of endian swapping, or ethernet offset
handling).

The imx-ocotp driver is the only user of the global post processing hook,
convert it to nvmem layouts and drop the global post pocessing hook.

For now, the layouts are selected by the device tree. But the idea is
that also board files or other drivers could set a layout. Although no
code for that exists yet.

Thanks to Miquel, the device tree bindings are already approved and merged.

NVMEM layouts as modules?
While possible in principle, it doesn't make any sense because the NVMEM
core can't be compiled as a module. The layouts needs to be available at
probe time. (That is also the reason why they get registered with
subsys_initcall().) So if the NVMEM core would be a module, the layouts
could be modules, too.

Michael Walle (18):
  net: add helper eth_addr_add()
  of: base: add of_parse_phandle_with_optional_args()
  of: property: make #.*-cells optional for simple props
  of: property: add #nvmem-cell-cells property
  nvmem: core: fix device node refcounting
  nvmem: core: add an index parameter to the cell
  nvmem: core: move struct nvmem_cell_info to nvmem-provider.h
  nvmem: core: drop the removal of the cells in nvmem_add_cells()
  nvmem: core: add nvmem_add_one_cell()
  nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()
  nvmem: core: introduce NVMEM layouts
  nvmem: core: add per-cell post processing
  nvmem: core: allow to modify a cell before adding it
  nvmem: imx-ocotp: replace global post processing with layouts
  nvmem: cell: drop global cell_post_process
  nvmem: core: provide own priv pointer in post process callback
  nvmem: layouts: add sl28vpd layout
  MAINTAINERS: add myself as sl28vpd nvmem layout driver

Miquel Raynal (2):
  nvmem: layouts: Add ONIE tlv layout driver
  MAINTAINERS: Add myself as ONIE tlv NVMEM layout maintainer

 Documentation/driver-api/nvmem.rst |  15 ++
 MAINTAINERS                        |  12 ++
 drivers/nvmem/Kconfig              |   4 +
 drivers/nvmem/Makefile             |   1 +
 drivers/nvmem/core.c               | 285 ++++++++++++++++++++++-------
 drivers/nvmem/imx-ocotp.c          |  34 ++--
 drivers/nvmem/layouts/Kconfig      |  23 +++
 drivers/nvmem/layouts/Makefile     |   7 +
 drivers/nvmem/layouts/onie-tlv.c   | 244 ++++++++++++++++++++++++
 drivers/nvmem/layouts/sl28vpd.c    | 153 ++++++++++++++++
 drivers/of/property.c              |   6 +-
 include/linux/etherdevice.h        |  14 ++
 include/linux/nvmem-consumer.h     |  17 +-
 include/linux/nvmem-provider.h     |  95 +++++++++-
 include/linux/of.h                 |  25 +++
 15 files changed, 836 insertions(+), 99 deletions(-)
 create mode 100644 drivers/nvmem/layouts/Kconfig
 create mode 100644 drivers/nvmem/layouts/Makefile
 create mode 100644 drivers/nvmem/layouts/onie-tlv.c
 create mode 100644 drivers/nvmem/layouts/sl28vpd.c

-- 
2.30.2

[PATCH v4 01/20] net: add helper eth_addr_add()

[Michael Walle]

Add a helper to add an offset to a ethernet address. This comes in handy
if you have a base ethernet address for multiple interfaces.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Jakub Kicinski <kuba@kernel.org>
---
changes since v3:
 - fix typo s/and/an/

changes since v2:
 - none

changes since v1:
 - none

 include/linux/etherdevice.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index a541f0c4f146..224645f17c33 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -507,6 +507,20 @@ static inline void eth_addr_inc(u8 *addr)
 	u64_to_ether_addr(u, addr);
 }
 
+/**
+ * eth_addr_add() - Add (or subtract) an offset to/from the given MAC address.
+ *
+ * @offset: Offset to add.
+ * @addr: Pointer to a six-byte array containing Ethernet address to increment.
+ */
+static inline void eth_addr_add(u8 *addr, long offset)
+{
+	u64 u = ether_addr_to_u64(addr);
+
+	u += offset;
+	u64_to_ether_addr(u, addr);
+}
+
 /**
  * is_etherdev_addr - Tell if given Ethernet address belongs to the device.
  * @dev: Pointer to a device structure
-- 
2.30.2

[PATCH v4 02/20] of: base: add of_parse_phandle_with_optional_args()

[Michael Walle]

Add a new variant of the of_parse_phandle_with_args() which treats the
cells name as optional. If it's missing, it is assumed that the phandle
has no arguments.

Up until now, a nvmem node didn't have any arguments, so all the device
trees haven't any '#*-cells' property. But there is a need for an
additional argument for the phandle, for which we need a '#*-cells'
property. Therefore, we need to support nvmem nodes with and without
this property.

Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Rob Herring <robh@kernel.org>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - none

 include/linux/of.h | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/include/linux/of.h b/include/linux/of.h
index 8b9f94386dc3..98c252d2d851 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -1008,6 +1008,31 @@ static inline int of_parse_phandle_with_fixed_args(const struct device_node *np,
 					    index, out_args);
 }
 
+/**
+ * of_parse_phandle_with_optional_args() - Find a node pointed by phandle in a list
+ * @np:		pointer to a device tree node containing a list
+ * @list_name:	property name that contains a list
+ * @cells_name:	property name that specifies phandles' arguments count
+ * @index:	index of a phandle to parse out
+ * @out_args:	optional pointer to output arguments structure (will be filled)
+ *
+ * Same as of_parse_phandle_with_args() except that if the cells_name property
+ * is not found, cell_count of 0 is assumed.
+ *
+ * This is used to useful, if you have a phandle which didn't have arguments
+ * before and thus doesn't have a '#*-cells' property but is now migrated to
+ * having arguments while retaining backwards compatibility.
+ */
+static inline int of_parse_phandle_with_optional_args(const struct device_node *np,
+						      const char *list_name,
+						      const char *cells_name,
+						      int index,
+						      struct of_phandle_args *out_args)
+{
+	return __of_parse_phandle_with_args(np, list_name, cells_name,
+					    0, index, out_args);
+}
+
 /**
  * of_property_count_u8_elems - Count the number of u8 elements in a property
  *
-- 
2.30.2

[PATCH v4 03/20] of: property: make #.*-cells optional for simple props

[Michael Walle]

Sometimes, future bindings for phandles will get additional arguments.
Thus the target node of the phandle will need a new #.*-cells property.
To be backwards compatible, this needs to be optional.

Prepare the DEFINE_SIMPLE_PROPS() to handle the cells name as optional.

Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
changes since v3:
 - new patch

 drivers/of/property.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 967f79b59016..9773bfeaed9f 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1254,8 +1254,8 @@ static struct device_node *parse_suffix_prop_cells(struct device_node *np,
 	if (strcmp_suffix(prop_name, suffix))
 		return NULL;
 
-	if (of_parse_phandle_with_args(np, prop_name, cells_name, index,
-				       &sup_args))
+	if (__of_parse_phandle_with_args(np, prop_name, cells_name, 0, index,
+					 &sup_args))
 		return NULL;
 
 	return sup_args.np;
-- 
2.30.2

Re: [PATCH v4 03/20] of: property: make #.*-cells optional for simple props

[Rob Herring]

On Wed, 23 Nov 2022 19:01:34 +0100, Michael Walle wrote:
> Sometimes, future bindings for phandles will get additional arguments.
> Thus the target node of the phandle will need a new #.*-cells property.
> To be backwards compatible, this needs to be optional.
> 
> Prepare the DEFINE_SIMPLE_PROPS() to handle the cells name as optional.
> 
> Signed-off-by: Michael Walle <michael@walle.cc>
> Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
> changes since v3:
>  - new patch
> 
>  drivers/of/property.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v4 04/20] of: property: add #nvmem-cell-cells property

[Michael Walle]

Bindings describe the new '#nvmem-cell-cells' property. Now that the
arguments count property is optional, we just add this property to the
nvmem-cells.

Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
changes since v3:
 - new patch

 drivers/of/property.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/of/property.c b/drivers/of/property.c
index 9773bfeaed9f..f60ac02e9dec 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1305,7 +1305,7 @@ DEFINE_SIMPLE_PROP(dmas, "dmas", "#dma-cells")
 DEFINE_SIMPLE_PROP(power_domains, "power-domains", "#power-domain-cells")
 DEFINE_SIMPLE_PROP(hwlocks, "hwlocks", "#hwlock-cells")
 DEFINE_SIMPLE_PROP(extcon, "extcon", NULL)
-DEFINE_SIMPLE_PROP(nvmem_cells, "nvmem-cells", NULL)
+DEFINE_SIMPLE_PROP(nvmem_cells, "nvmem-cells", "#nvmem-cell-cells")
 DEFINE_SIMPLE_PROP(phys, "phys", "#phy-cells")
 DEFINE_SIMPLE_PROP(wakeup_parent, "wakeup-parent", NULL)
 DEFINE_SIMPLE_PROP(pinctrl0, "pinctrl-0", NULL)
-- 
2.30.2

Re: [PATCH v4 04/20] of: property: add #nvmem-cell-cells property

[Rob Herring]

On Wed, 23 Nov 2022 19:01:35 +0100, Michael Walle wrote:
> Bindings describe the new '#nvmem-cell-cells' property. Now that the
> arguments count property is optional, we just add this property to the
> nvmem-cells.
> 
> Signed-off-by: Michael Walle <michael@walle.cc>
> Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
> ---
> changes since v3:
>  - new patch
> 
>  drivers/of/property.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

[PATCH v4 05/20] nvmem: core: fix device node refcounting

[Michael Walle]

In of_nvmem_cell_get(), of_get_next_parent() is used on cell_np. This
will decrement the refcount on cell_np, but cell_np is still used later
in the code. Use of_get_parent() instead and of_node_put() in the
appropriate places.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - new patch

 drivers/nvmem/core.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 321d7d63e068..205a427f564d 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -1242,16 +1242,21 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 	if (!cell_np)
 		return ERR_PTR(-ENOENT);
 
-	nvmem_np = of_get_next_parent(cell_np);
-	if (!nvmem_np)
+	nvmem_np = of_get_parent(cell_np);
+	if (!nvmem_np) {
+		of_node_put(cell_np);
 		return ERR_PTR(-EINVAL);
+	}
 
 	nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
 	of_node_put(nvmem_np);
-	if (IS_ERR(nvmem))
+	if (IS_ERR(nvmem)) {
+		of_node_put(cell_np);
 		return ERR_CAST(nvmem);
+	}
 
 	cell_entry = nvmem_find_cell_entry_by_node(nvmem, cell_np);
+	of_node_put(cell_np);
 	if (!cell_entry) {
 		__nvmem_device_put(nvmem);
 		return ERR_PTR(-ENOENT);
-- 
2.30.2

[PATCH v4 06/20] nvmem: core: add an index parameter to the cell

[Michael Walle]

Sometimes a cell can represend multiple values. For example, a base
ethernet address stored in the NVMEM can be expanded into multiple
discreet ones by adding an offset.

For this use case, introduce an index parameter which is then used to
distiguish between values. This parameter will then be passed to the
post process hook which can then use it to create different values
during reading.

At the moment, there is only support for the device tree path. You can
add the index to the phandle, e.g.

  &net {
          nvmem-cells = <&base_mac_address 2>;
          nvmem-cell-names = "mac-address";
  };

  &nvmem_provider {
          base_mac_address: base-mac-address@0 {
                  #nvmem-cell-cells = <1>;
                  reg = <0 6>;
          };
  };

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - none

 drivers/nvmem/core.c           | 37 ++++++++++++++++++++++++----------
 drivers/nvmem/imx-ocotp.c      |  4 ++--
 include/linux/nvmem-provider.h |  4 ++--
 3 files changed, 30 insertions(+), 15 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 205a427f564d..24573e63e5a9 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -60,6 +60,7 @@ struct nvmem_cell_entry {
 struct nvmem_cell {
 	struct nvmem_cell_entry *entry;
 	const char		*id;
+	int			index;
 };
 
 static DEFINE_MUTEX(nvmem_mutex);
@@ -1127,7 +1128,8 @@ struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id)
 }
 EXPORT_SYMBOL_GPL(devm_nvmem_device_get);
 
-static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, const char *id)
+static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
+					    const char *id, int index)
 {
 	struct nvmem_cell *cell;
 	const char *name = NULL;
@@ -1146,6 +1148,7 @@ static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry, cons
 
 	cell->id = name;
 	cell->entry = entry;
+	cell->index = index;
 
 	return cell;
 }
@@ -1184,7 +1187,7 @@ nvmem_cell_get_from_lookup(struct device *dev, const char *con_id)
 				__nvmem_device_put(nvmem);
 				cell = ERR_PTR(-ENOENT);
 			} else {
-				cell = nvmem_create_cell(cell_entry, con_id);
+				cell = nvmem_create_cell(cell_entry, con_id, 0);
 				if (IS_ERR(cell))
 					__nvmem_device_put(nvmem);
 			}
@@ -1232,15 +1235,27 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 	struct nvmem_device *nvmem;
 	struct nvmem_cell_entry *cell_entry;
 	struct nvmem_cell *cell;
+	struct of_phandle_args cell_spec;
 	int index = 0;
+	int cell_index = 0;
+	int ret;
 
 	/* if cell name exists, find index to the name */
 	if (id)
 		index = of_property_match_string(np, "nvmem-cell-names", id);
 
-	cell_np = of_parse_phandle(np, "nvmem-cells", index);
-	if (!cell_np)
-		return ERR_PTR(-ENOENT);
+	ret = of_parse_phandle_with_optional_args(np, "nvmem-cells",
+						  "#nvmem-cell-cells",
+						  index, &cell_spec);
+	if (ret)
+		return ERR_PTR(ret);
+
+	if (cell_spec.args_count > 1)
+		return ERR_PTR(-EINVAL);
+
+	cell_np = cell_spec.np;
+	if (cell_spec.args_count)
+		cell_index = cell_spec.args[0];
 
 	nvmem_np = of_get_parent(cell_np);
 	if (!nvmem_np) {
@@ -1262,7 +1277,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 		return ERR_PTR(-ENOENT);
 	}
 
-	cell = nvmem_create_cell(cell_entry, id);
+	cell = nvmem_create_cell(cell_entry, id, cell_index);
 	if (IS_ERR(cell))
 		__nvmem_device_put(nvmem);
 
@@ -1415,8 +1430,8 @@ static void nvmem_shift_read_buffer_in_place(struct nvmem_cell_entry *cell, void
 }
 
 static int __nvmem_cell_read(struct nvmem_device *nvmem,
-		      struct nvmem_cell_entry *cell,
-		      void *buf, size_t *len, const char *id)
+			     struct nvmem_cell_entry *cell,
+			     void *buf, size_t *len, const char *id, int index)
 {
 	int rc;
 
@@ -1430,7 +1445,7 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
 		nvmem_shift_read_buffer_in_place(cell, buf);
 
 	if (nvmem->cell_post_process) {
-		rc = nvmem->cell_post_process(nvmem->priv, id,
+		rc = nvmem->cell_post_process(nvmem->priv, id, index,
 					      cell->offset, buf, cell->bytes);
 		if (rc)
 			return rc;
@@ -1465,7 +1480,7 @@ void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len)
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
 
-	rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id);
+	rc = __nvmem_cell_read(nvmem, cell->entry, buf, len, cell->id, cell->index);
 	if (rc) {
 		kfree(buf);
 		return ERR_PTR(rc);
@@ -1778,7 +1793,7 @@ ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem,
 	if (rc)
 		return rc;
 
-	rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL);
+	rc = __nvmem_cell_read(nvmem, &cell, buf, &len, NULL, 0);
 	if (rc)
 		return rc;
 
diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index 14284e866f26..e9b52ecb3f72 100644
--- a/drivers/nvmem/imx-ocotp.c
+++ b/drivers/nvmem/imx-ocotp.c
@@ -222,8 +222,8 @@ static int imx_ocotp_read(void *context, unsigned int offset,
 	return ret;
 }
 
-static int imx_ocotp_cell_pp(void *context, const char *id, unsigned int offset,
-			     void *data, size_t bytes)
+static int imx_ocotp_cell_pp(void *context, const char *id, int index,
+			     unsigned int offset, void *data, size_t bytes)
 {
 	struct ocotp_priv *priv = context;
 
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 50caa117cb62..8f964b394292 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -20,8 +20,8 @@ typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
 typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
 				 void *val, size_t bytes);
 /* used for vendor specific post processing of cell data */
-typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, unsigned int offset,
-					  void *buf, size_t bytes);
+typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,
+					 unsigned int offset, void *buf, size_t bytes);
 
 enum nvmem_type {
 	NVMEM_TYPE_UNKNOWN = 0,
-- 
2.30.2

[PATCH v4 07/20] nvmem: core: move struct nvmem_cell_info to nvmem-provider.h

[Michael Walle]

struct nvmem_cell_info is used to describe a cell. Thus this should
really be in the nvmem-provider's header. There are two (unused) nvmem
access methods which use the nvmem_cell_info to describe the cell to be
accesses. One can argue, that they will create a cell before accessing,
thus they are both a provider and a consumer.

struct nvmem_cell_info will get used more and more by nvmem-providers,
don't force them to also include the consumer header, although they are
not.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - new patch

 include/linux/nvmem-consumer.h | 10 +---------
 include/linux/nvmem-provider.h | 19 ++++++++++++++++++-
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h
index 980f9c9ac0bc..1f62f7ba71ca 100644
--- a/include/linux/nvmem-consumer.h
+++ b/include/linux/nvmem-consumer.h
@@ -18,15 +18,7 @@ struct device_node;
 /* consumer cookie */
 struct nvmem_cell;
 struct nvmem_device;
-
-struct nvmem_cell_info {
-	const char		*name;
-	unsigned int		offset;
-	unsigned int		bytes;
-	unsigned int		bit_offset;
-	unsigned int		nbits;
-	struct device_node	*np;
-};
+struct nvmem_cell_info;
 
 /**
  * struct nvmem_cell_lookup - cell lookup entry
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 8f964b394292..14a32a1bc249 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -14,7 +14,6 @@
 #include <linux/gpio/consumer.h>
 
 struct nvmem_device;
-struct nvmem_cell_info;
 typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
 				void *val, size_t bytes);
 typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
@@ -47,6 +46,24 @@ struct nvmem_keepout {
 	unsigned char value;
 };
 
+/**
+ * struct nvmem_cell_info - NVMEM cell description
+ * @name:	Name.
+ * @offset:	Offset within the NVMEM device.
+ * @bytes:	Length of the cell.
+ * @bit_offset:	Bit offset if cell is smaller than a byte.
+ * @nbits:	Number of bits.
+ * @np:		Optional device_node pointer.
+ */
+struct nvmem_cell_info {
+	const char		*name;
+	unsigned int		offset;
+	unsigned int		bytes;
+	unsigned int		bit_offset;
+	unsigned int		nbits;
+	struct device_node	*np;
+};
+
 /**
  * struct nvmem_config - NVMEM device configuration
  *
-- 
2.30.2

[PATCH v4 08/20] nvmem: core: drop the removal of the cells in nvmem_add_cells()

[Michael Walle]

If nvmem_add_cells() fails, the whole nvmem_register() will fail
and the cells will then be removed anyway. This is a preparation
to introduce a nvmem_add_one_cell() which can then be used by
nvmem_add_cells().

This is then the same to what nvmem_add_cells_from_table() and
nvmem_add_cells_from_of() do.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - fix typo, s/prepartion/preparation/

changes since v2:
 - none

changes since v1:
 - none

 drivers/nvmem/core.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 24573e63e5a9..7c76e0e0072e 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -515,7 +515,7 @@ static int nvmem_add_cells(struct nvmem_device *nvmem,
 		    int ncells)
 {
 	struct nvmem_cell_entry **cells;
-	int i, rval;
+	int i, rval = 0;
 
 	cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
 	if (!cells)
@@ -525,28 +525,22 @@ static int nvmem_add_cells(struct nvmem_device *nvmem,
 		cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
 		if (!cells[i]) {
 			rval = -ENOMEM;
-			goto err;
+			goto out;
 		}
 
 		rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, &info[i], cells[i]);
 		if (rval) {
 			kfree(cells[i]);
-			goto err;
+			goto out;
 		}
 
 		nvmem_cell_entry_add(cells[i]);
 	}
 
+out:
 	/* remove tmp array */
 	kfree(cells);
 
-	return 0;
-err:
-	while (i--)
-		nvmem_cell_entry_drop(cells[i]);
-
-	kfree(cells);
-
 	return rval;
 }
 
-- 
2.30.2

[PATCH v4 09/20] nvmem: core: add nvmem_add_one_cell()

[Michael Walle]

Add a new function to add exactly one cell. This will be used by the
nvmem layout drivers to add custom cells. In contrast to the
nvmem_add_cells(), this has the advantage that we don't have to assemble
a list of cells on runtime.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - add EXPORT_SYMBOL_GPL()

changes since v1:
 - none

 drivers/nvmem/core.c           | 59 ++++++++++++++++++++--------------
 include/linux/nvmem-provider.h |  8 +++++
 2 files changed, 43 insertions(+), 24 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 7c76e0e0072e..cb25bf29dea7 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -501,6 +501,36 @@ static int nvmem_cell_info_to_nvmem_cell_entry(struct nvmem_device *nvmem,
 	return 0;
 }
 
+/**
+ * nvmem_add_one_cell() - Add one cell information to an nvmem device
+ *
+ * @nvmem: nvmem device to add cells to.
+ * @info: nvmem cell info to add to the device
+ *
+ * Return: 0 or negative error code on failure.
+ */
+int nvmem_add_one_cell(struct nvmem_device *nvmem,
+		       const struct nvmem_cell_info *info)
+{
+	struct nvmem_cell_entry *cell;
+	int rval;
+
+	cell = kzalloc(sizeof(*cell), GFP_KERNEL);
+	if (!cell)
+		return -ENOMEM;
+
+	rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, info, cell);
+	if (rval) {
+		kfree(cell);
+		return rval;
+	}
+
+	nvmem_cell_entry_add(cell);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nvmem_add_one_cell);
+
 /**
  * nvmem_add_cells() - Add cell information to an nvmem device
  *
@@ -514,34 +544,15 @@ static int nvmem_add_cells(struct nvmem_device *nvmem,
 		    const struct nvmem_cell_info *info,
 		    int ncells)
 {
-	struct nvmem_cell_entry **cells;
-	int i, rval = 0;
-
-	cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL);
-	if (!cells)
-		return -ENOMEM;
+	int i, rval;
 
 	for (i = 0; i < ncells; i++) {
-		cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL);
-		if (!cells[i]) {
-			rval = -ENOMEM;
-			goto out;
-		}
-
-		rval = nvmem_cell_info_to_nvmem_cell_entry(nvmem, &info[i], cells[i]);
-		if (rval) {
-			kfree(cells[i]);
-			goto out;
-		}
-
-		nvmem_cell_entry_add(cells[i]);
+		rval = nvmem_add_one_cell(nvmem, &info[i]);
+		if (rval)
+			return rval;
 	}
 
-out:
-	/* remove tmp array */
-	kfree(cells);
-
-	return rval;
+	return 0;
 }
 
 /**
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 14a32a1bc249..385d29168008 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -155,6 +155,9 @@ struct nvmem_device *devm_nvmem_register(struct device *dev,
 void nvmem_add_cell_table(struct nvmem_cell_table *table);
 void nvmem_del_cell_table(struct nvmem_cell_table *table);
 
+int nvmem_add_one_cell(struct nvmem_device *nvmem,
+		       const struct nvmem_cell_info *info);
+
 #else
 
 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
@@ -172,6 +175,11 @@ devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 
 static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
 static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
+static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
+				     const struct nvmem_cell_info *info)
+{
+	return -EOPNOTSUPP;
+}
 
 #endif /* CONFIG_NVMEM */
 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */
-- 
2.30.2

[PATCH v4 10/20] nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()

[Michael Walle]

Convert nvmem_add_cells_from_of() to use the new nvmem_add_one_cell().
This will remove duplicate code and it will make it possible to add a
hook to a nvmem layout in between, which can change fields before the
cell is finally added.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - new patch

 drivers/nvmem/core.c | 38 ++++++++++++++------------------------
 1 file changed, 14 insertions(+), 24 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index cb25bf29dea7..26459d582e99 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -688,15 +688,15 @@ static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 
 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 {
-	struct device_node *parent, *child;
 	struct device *dev = &nvmem->dev;
 	struct nvmem_cell_entry *cell;
+	struct device_node *child;
 	const __be32 *addr;
-	int len;
+	int len, ret;
 
-	parent = dev->of_node;
+	for_each_child_of_node(dev->of_node, child) {
+		struct nvmem_cell_info info = {0};
 
-	for_each_child_of_node(parent, child) {
 		addr = of_get_property(child, "reg", &len);
 		if (!addr)
 			continue;
@@ -712,34 +712,24 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 			return -ENOMEM;
 		}
 
-		cell->nvmem = nvmem;
-		cell->offset = be32_to_cpup(addr++);
-		cell->bytes = be32_to_cpup(addr);
-		cell->name = kasprintf(GFP_KERNEL, "%pOFn", child);
+		info.offset = be32_to_cpup(addr++);
+		info.bytes = be32_to_cpup(addr);
+		info.name = kasprintf(GFP_KERNEL, "%pOFn", child);
 
 		addr = of_get_property(child, "bits", &len);
 		if (addr && len == (2 * sizeof(u32))) {
-			cell->bit_offset = be32_to_cpup(addr++);
-			cell->nbits = be32_to_cpup(addr);
+			info.bit_offset = be32_to_cpup(addr++);
+			info.nbits = be32_to_cpup(addr);
 		}
 
-		if (cell->nbits)
-			cell->bytes = DIV_ROUND_UP(
-					cell->nbits + cell->bit_offset,
-					BITS_PER_BYTE);
+		info.np = of_node_get(child);
 
-		if (!IS_ALIGNED(cell->offset, nvmem->stride)) {
-			dev_err(dev, "cell %s unaligned to nvmem stride %d\n",
-				cell->name, nvmem->stride);
-			/* Cells already added will be freed later. */
-			kfree_const(cell->name);
-			kfree(cell);
+		ret = nvmem_add_one_cell(nvmem, &info);
+		kfree(info.name);
+		if (ret) {
 			of_node_put(child);
-			return -EINVAL;
+			return ret;
 		}
-
-		cell->np = of_node_get(child);
-		nvmem_cell_entry_add(cell);
 	}
 
 	return 0;
-- 
2.30.2

Re: [PATCH v4 10/20] nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()

[Dan Carpenter]

Hi Michael,

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Michael-Walle/nvmem-core-introduce-NVMEM-layouts/20221124-020554
patch link:    https://lore.kernel.org/r/20221123180151.2160033-11-michael%40walle.cc
patch subject: [PATCH v4 10/20] nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()
config: i386-randconfig-m021
compiler: gcc-11 (Debian 11.3.0-8) 11.3.0

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <error27@gmail.com>

New smatch warnings:
drivers/nvmem/core.c:731 nvmem_add_cells_from_of() warn: possible memory leak of 'cell'

Old smatch warnings:
drivers/nvmem/core.c:735 nvmem_add_cells_from_of() warn: possible memory leak of 'cell'

vim +/cell +731 drivers/nvmem/core.c

e888d445ac33a5 Bartosz Golaszewski 2018-09-21  689  static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  690  {
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  691  	struct device *dev = &nvmem->dev;
7ae6478b304bc0 Srinivas Kandagatla 2021-10-13  692  	struct nvmem_cell_entry *cell;
18f50dbcfd3676 Michael Walle       2022-11-23  693  	struct device_node *child;
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  694  	const __be32 *addr;
18f50dbcfd3676 Michael Walle       2022-11-23  695  	int len, ret;
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  696  
18f50dbcfd3676 Michael Walle       2022-11-23  697  	for_each_child_of_node(dev->of_node, child) {
18f50dbcfd3676 Michael Walle       2022-11-23  698  		struct nvmem_cell_info info = {0};
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  699  
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  700  		addr = of_get_property(child, "reg", &len);
0445efacec75b8 Ahmad Fatoum        2021-01-29  701  		if (!addr)
0445efacec75b8 Ahmad Fatoum        2021-01-29  702  			continue;
0445efacec75b8 Ahmad Fatoum        2021-01-29  703  		if (len < 2 * sizeof(u32)) {
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  704  			dev_err(dev, "nvmem: invalid reg on %pOF\n", child);
63879e2964bcee Christophe JAILLET  2021-06-11  705  			of_node_put(child);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  706  			return -EINVAL;
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  707  		}
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  708  
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  709  		cell = kzalloc(sizeof(*cell), GFP_KERNEL);
63879e2964bcee Christophe JAILLET  2021-06-11  710  		if (!cell) {
63879e2964bcee Christophe JAILLET  2021-06-11  711  			of_node_put(child);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  712  			return -ENOMEM;
63879e2964bcee Christophe JAILLET  2021-06-11  713  		}

Seems like "cell" is not used any more so this just leaks.

e888d445ac33a5 Bartosz Golaszewski 2018-09-21  714  
18f50dbcfd3676 Michael Walle       2022-11-23  715  		info.offset = be32_to_cpup(addr++);
18f50dbcfd3676 Michael Walle       2022-11-23  716  		info.bytes = be32_to_cpup(addr);
18f50dbcfd3676 Michael Walle       2022-11-23  717  		info.name = kasprintf(GFP_KERNEL, "%pOFn", child);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  718  
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  719  		addr = of_get_property(child, "bits", &len);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  720  		if (addr && len == (2 * sizeof(u32))) {
18f50dbcfd3676 Michael Walle       2022-11-23  721  			info.bit_offset = be32_to_cpup(addr++);
18f50dbcfd3676 Michael Walle       2022-11-23  722  			info.nbits = be32_to_cpup(addr);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  723  		}
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  724  
18f50dbcfd3676 Michael Walle       2022-11-23  725  		info.np = of_node_get(child);
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  726  
18f50dbcfd3676 Michael Walle       2022-11-23  727  		ret = nvmem_add_one_cell(nvmem, &info);
18f50dbcfd3676 Michael Walle       2022-11-23  728  		kfree(info.name);
18f50dbcfd3676 Michael Walle       2022-11-23  729  		if (ret) {
63879e2964bcee Christophe JAILLET  2021-06-11  730  			of_node_put(child);
18f50dbcfd3676 Michael Walle       2022-11-23 @731  			return ret;
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  732  		}
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  733  	}
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  734  
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  735  	return 0;
e888d445ac33a5 Bartosz Golaszewski 2018-09-21  736  }

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

Re: [PATCH v4 10/20] nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()

[Michael Walle]

Am 2022-12-03 09:30, schrieb Dan Carpenter:
> Hi Michael,
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:
> https://github.com/intel-lab-lkp/linux/commits/Michael-Walle/nvmem-core-introduce-NVMEM-layouts/20221124-020554
> patch link:
> https://lore.kernel.org/r/20221123180151.2160033-11-michael%40walle.cc
> patch subject: [PATCH v4 10/20] nvmem: core: use nvmem_add_one_cell()
> in nvmem_add_cells_from_of()
> config: i386-randconfig-m021
> compiler: gcc-11 (Debian 11.3.0-8) 11.3.0
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Reported-by: Dan Carpenter <error27@gmail.com>
> 
> New smatch warnings:
> drivers/nvmem/core.c:731 nvmem_add_cells_from_of() warn: possible
> memory leak of 'cell'
> 
> Old smatch warnings:
> drivers/nvmem/core.c:735 nvmem_add_cells_from_of() warn: possible
> memory leak of 'cell'
> 
> vim +/cell +731 drivers/nvmem/core.c
> 
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  689  static int
> nvmem_add_cells_from_of(struct nvmem_device *nvmem)
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  690  {
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  691  	struct device
> *dev = &nvmem->dev;
> 7ae6478b304bc0 Srinivas Kandagatla 2021-10-13  692  	struct
> nvmem_cell_entry *cell;
> 18f50dbcfd3676 Michael Walle       2022-11-23  693  	struct device_node 
> *child;
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  694  	const __be32 
> *addr;
> 18f50dbcfd3676 Michael Walle       2022-11-23  695  	int len, ret;
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  696
> 18f50dbcfd3676 Michael Walle       2022-11-23  697
> 	for_each_child_of_node(dev->of_node, child) {
> 18f50dbcfd3676 Michael Walle       2022-11-23  698  		struct
> nvmem_cell_info info = {0};
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  699
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  700  		addr =
> of_get_property(child, "reg", &len);
> 0445efacec75b8 Ahmad Fatoum        2021-01-29  701  		if (!addr)
> 0445efacec75b8 Ahmad Fatoum        2021-01-29  702  			continue;
> 0445efacec75b8 Ahmad Fatoum        2021-01-29  703  		if (len < 2 *
> sizeof(u32)) {
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  704  			dev_err(dev,
> "nvmem: invalid reg on %pOF\n", child);
> 63879e2964bcee Christophe JAILLET  2021-06-11  705  
> 			of_node_put(child);
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  706  			return -EINVAL;
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  707  		}
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  708
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  709  		cell =
> kzalloc(sizeof(*cell), GFP_KERNEL);
> 63879e2964bcee Christophe JAILLET  2021-06-11  710  		if (!cell) {
> 63879e2964bcee Christophe JAILLET  2021-06-11  711  
> 			of_node_put(child);
> e888d445ac33a5 Bartosz Golaszewski 2018-09-21  712  			return -ENOMEM;
> 63879e2964bcee Christophe JAILLET  2021-06-11  713  		}
> 
> Seems like "cell" is not used any more so this just leaks.

Damn, what a stupid bug from me. Thanks for catching this.

-michael

[PATCH v4 11/20] nvmem: core: introduce NVMEM layouts

[Michael Walle]

NVMEM layouts are used to generate NVMEM cells during runtime. Think of
an EEPROM with a well-defined conent. For now, the content can be
described by a device tree or a board file. But this only works if the
offsets and lengths are static and don't change. One could also argue
that putting the layout of the EEPROM in the device tree is the wrong
place. Instead, the device tree should just have a specific compatible
string.

Right now there are two use cases:
 (1) The NVMEM cell needs special processing. E.g. if it only specifies
     a base MAC address offset and you need to add an offset, or it
     needs to parse a MAC from ASCII format or some proprietary format.
     (Post processing of cells is added in a later commit).
 (2) u-boot environment parsing. The cells don't have a particular
     offset but it needs parsing the content to determine the offsets
     and length.

Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - check return code of .add_cells()

changes since v2:
 - look for "nvmem-layout" node and its compatible
 - add of_nvmem_layout_get_container()
 - special handling in of_nvmem_cell_get()

changes since v1:
 - add documentation in nvmem.rst
 - add nvmem_layout_unregister() + necessary module tracking
 - make it possible to supply a layout via nvmem_register()
 - check add_cells, before calling

 Documentation/driver-api/nvmem.rst |  15 ++++
 drivers/nvmem/Kconfig              |   4 +
 drivers/nvmem/Makefile             |   1 +
 drivers/nvmem/core.c               | 118 +++++++++++++++++++++++++++++
 drivers/nvmem/layouts/Kconfig      |   5 ++
 drivers/nvmem/layouts/Makefile     |   4 +
 include/linux/nvmem-consumer.h     |   7 ++
 include/linux/nvmem-provider.h     |  51 +++++++++++++
 8 files changed, 205 insertions(+)
 create mode 100644 drivers/nvmem/layouts/Kconfig
 create mode 100644 drivers/nvmem/layouts/Makefile

diff --git a/Documentation/driver-api/nvmem.rst b/Documentation/driver-api/nvmem.rst
index e3366322d46c..de221e91c8e3 100644
--- a/Documentation/driver-api/nvmem.rst
+++ b/Documentation/driver-api/nvmem.rst
@@ -185,3 +185,18 @@ ex::
 =====================
 
 See Documentation/devicetree/bindings/nvmem/nvmem.txt
+
+8. NVMEM layouts
+================
+
+NVMEM layouts are yet another mechanism to create cells. With the device
+tree binding it is possible to specify simple cells by using an offset
+and a length. Sometimes, the cells doesn't have a static offset, but
+the content is still well defined, e.g. tag-length-values. In this case,
+the NVMEM device content has to be first parsed and the cells need to
+be added accordingly. Layouts let you read the content of the NVMEM device
+and let you add cells dynamically.
+
+Another use case for layouts is the post processing of cells. With layouts,
+it is possible to associate a custom post processing hook to a cell. It
+even possible to add this hook to cells not created by the layout itself.
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 755f551426b5..0e10b5b094b9 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -21,6 +21,10 @@ config NVMEM_SYSFS
 	 This interface is mostly used by userspace applications to
 	 read/write directly into nvmem.
 
+# Layouts
+
+source "drivers/nvmem/layouts/Kconfig"
+
 # Devices
 
 config NVMEM_APPLE_EFUSES
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index fa80fe17e567..4cf87ef6c24d 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -5,6 +5,7 @@
 
 obj-$(CONFIG_NVMEM)		+= nvmem_core.o
 nvmem_core-y			:= core.o
+obj-y				+= layouts/
 
 # Devices
 obj-$(CONFIG_NVMEM_APPLE_EFUSES)	+= nvmem-apple-efuses.o
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 26459d582e99..87ba1e3a5bd4 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -40,6 +40,7 @@ struct nvmem_device {
 	nvmem_reg_write_t	reg_write;
 	nvmem_cell_post_process_t cell_post_process;
 	struct gpio_desc	*wp_gpio;
+	struct nvmem_layout	*layout;
 	void *priv;
 };
 
@@ -74,6 +75,9 @@ static LIST_HEAD(nvmem_lookup_list);
 
 static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
 
+static DEFINE_SPINLOCK(nvmem_layout_lock);
+static LIST_HEAD(nvmem_layouts);
+
 static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
 			    void *val, size_t bytes)
 {
@@ -735,6 +739,99 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 	return 0;
 }
 
+int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner)
+{
+	layout->owner = owner;
+
+	spin_lock(&nvmem_layout_lock);
+	list_add(&layout->node, &nvmem_layouts);
+	spin_unlock(&nvmem_layout_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__nvmem_layout_register);
+
+void nvmem_layout_unregister(struct nvmem_layout *layout)
+{
+	spin_lock(&nvmem_layout_lock);
+	list_del(&layout->node);
+	spin_unlock(&nvmem_layout_lock);
+}
+EXPORT_SYMBOL_GPL(nvmem_layout_unregister);
+
+static struct nvmem_layout *nvmem_layout_get(struct nvmem_device *nvmem)
+{
+	struct device_node *layout_np, *np = nvmem->dev.of_node;
+	struct nvmem_layout *l, *layout = NULL;
+
+	layout_np = of_get_child_by_name(np, "nvmem-layout");
+	if (!layout_np)
+		return NULL;
+
+	spin_lock(&nvmem_layout_lock);
+
+	list_for_each_entry(l, &nvmem_layouts, node) {
+		if (of_match_node(l->of_match_table, layout_np)) {
+			if (try_module_get(l->owner))
+				layout = l;
+
+			break;
+		}
+	}
+
+	spin_unlock(&nvmem_layout_lock);
+	of_node_put(layout_np);
+
+	return layout;
+}
+
+static void nvmem_layout_put(struct nvmem_layout *layout)
+{
+	if (layout)
+		module_put(layout->owner);
+}
+
+static int nvmem_add_cells_from_layout(struct nvmem_device *nvmem)
+{
+	struct nvmem_layout *layout = nvmem->layout;
+	int ret;
+
+	if (layout && layout->add_cells) {
+		ret = layout->add_cells(&nvmem->dev, nvmem, layout);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_OF)
+/**
+ * of_nvmem_layout_get_container() - Get OF node to layout container.
+ *
+ * @nvmem: nvmem device.
+ *
+ * Return: a node pointer with refcount incremented or NULL if no
+ * container exists. Use of_node_put() on it when done.
+ */
+struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
+{
+	return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
+}
+EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
+#endif
+
+const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
+					struct nvmem_layout *layout)
+{
+	const struct of_device_id *match;
+
+	match = of_match_node(layout->of_match_table, nvmem->dev.of_node);
+
+	return match ? match->data : NULL;
+}
+EXPORT_SYMBOL_GPL(nvmem_layout_get_match_data);
+
 /**
  * nvmem_register() - Register a nvmem device for given nvmem_config.
  * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem
@@ -849,6 +946,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 			goto err_device_del;
 	}
 
+	/*
+	 * If the driver supplied a layout by config->layout, the module
+	 * pointer will be NULL and nvmem_layout_put() will be a noop.
+	 */
+	nvmem->layout = config->layout ?: nvmem_layout_get(nvmem);
+
 	if (config->cells) {
 		rval = nvmem_add_cells(nvmem, config->cells, config->ncells);
 		if (rval)
@@ -863,6 +966,10 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	if (rval)
 		goto err_remove_cells;
 
+	rval = nvmem_add_cells_from_layout(nvmem);
+	if (rval)
+		goto err_remove_cells;
+
 	blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem);
 
 	return nvmem;
@@ -872,6 +979,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 err_teardown_compat:
 	if (config->compat)
 		nvmem_sysfs_remove_compat(nvmem, config);
+	nvmem_layout_put(nvmem->layout);
 err_device_del:
 	device_del(&nvmem->dev);
 err_put_device:
@@ -893,6 +1001,7 @@ static void nvmem_device_release(struct kref *kref)
 		device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
 
 	nvmem_device_remove_all_cells(nvmem);
+	nvmem_layout_put(nvmem->layout);
 	device_unregister(&nvmem->dev);
 }
 
@@ -1258,6 +1367,15 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id)
 		return ERR_PTR(-EINVAL);
 	}
 
+	/* nvmem layouts produce cells within the nvmem-layout container */
+	if (of_node_name_eq(nvmem_np, "nvmem-layout")) {
+		nvmem_np = of_get_next_parent(nvmem_np);
+		if (!nvmem_np) {
+			of_node_put(cell_np);
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
 	nvmem = __nvmem_device_get(nvmem_np, device_match_of_node);
 	of_node_put(nvmem_np);
 	if (IS_ERR(nvmem)) {
diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
new file mode 100644
index 000000000000..9ad3911d1605
--- /dev/null
+++ b/drivers/nvmem/layouts/Kconfig
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+menu "Layout Types"
+
+endmenu
diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile
new file mode 100644
index 000000000000..6fdb3c60a4fa
--- /dev/null
+++ b/drivers/nvmem/layouts/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for nvmem layouts.
+#
diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h
index 1f62f7ba71ca..fa030d93b768 100644
--- a/include/linux/nvmem-consumer.h
+++ b/include/linux/nvmem-consumer.h
@@ -239,6 +239,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
 				     const char *id);
 struct nvmem_device *of_nvmem_device_get(struct device_node *np,
 					 const char *name);
+struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem);
 #else
 static inline struct nvmem_cell *of_nvmem_cell_get(struct device_node *np,
 						   const char *id)
@@ -251,6 +252,12 @@ static inline struct nvmem_device *of_nvmem_device_get(struct device_node *np,
 {
 	return ERR_PTR(-EOPNOTSUPP);
 }
+
+static inline struct device_node *
+of_nvmem_layout_get_container(struct nvmem_device *nvmem)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
 #endif /* CONFIG_NVMEM && CONFIG_OF */
 
 #endif  /* ifndef _LINUX_NVMEM_CONSUMER_H */
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 385d29168008..4185767c114f 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -89,6 +89,7 @@ struct nvmem_cell_info {
  * @priv:	User context passed to read/write callbacks.
  * @wp-gpio:	Write protect pin
  * @ignore_wp:  Write Protect pin is managed by the provider.
+ * @layout:	Fixed layout associated with this nvmem device.
  *
  * Note: A default "nvmem<id>" name will be assigned to the device if
  * no name is specified in its configuration. In such case "<id>" is
@@ -111,6 +112,7 @@ struct nvmem_config {
 	bool			read_only;
 	bool			root_only;
 	bool			ignore_wp;
+	struct nvmem_layout	*layout;
 	struct device_node	*of_node;
 	bool			no_of_node;
 	nvmem_reg_read_t	reg_read;
@@ -144,6 +146,33 @@ struct nvmem_cell_table {
 	struct list_head	node;
 };
 
+/**
+ * struct nvmem_layout - NVMEM layout definitions
+ *
+ * @name:		Layout name.
+ * @of_match_table:	Open firmware match table.
+ * @add_cells:		Will be called if a nvmem device is found which
+ *			has this layout. The function will add layout
+ *			specific cells with nvmem_add_one_cell().
+ * @owner:		Pointer to struct module.
+ * @node:		List node.
+ *
+ * A nvmem device can hold a well defined structure which can just be
+ * evaluated during runtime. For example a TLV list, or a list of "name=val"
+ * pairs. A nvmem layout can parse the nvmem device and add appropriate
+ * cells.
+ */
+struct nvmem_layout {
+	const char *name;
+	const struct of_device_id *of_match_table;
+	int (*add_cells)(struct device *dev, struct nvmem_device *nvmem,
+			 struct nvmem_layout *layout);
+
+	/* private */
+	struct module *owner;
+	struct list_head node;
+};
+
 #if IS_ENABLED(CONFIG_NVMEM)
 
 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
@@ -158,6 +187,14 @@ void nvmem_del_cell_table(struct nvmem_cell_table *table);
 int nvmem_add_one_cell(struct nvmem_device *nvmem,
 		       const struct nvmem_cell_info *info);
 
+int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner);
+#define nvmem_layout_register(layout) \
+	__nvmem_layout_register(layout, THIS_MODULE)
+void nvmem_layout_unregister(struct nvmem_layout *layout);
+
+const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
+					struct nvmem_layout *layout);
+
 #else
 
 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
@@ -181,5 +218,19 @@ static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
 	return -EOPNOTSUPP;
 }
 
+static inline int nvmem_layout_register(struct nvmem_layout *layout)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {}
+
+static inline const void *
+nvmem_layout_get_match_data(struct nvmem_device *nvmem,
+			    struct nvmem_layout *layout)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_NVMEM */
 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */
-- 
2.30.2

[PATCH v4 12/20] nvmem: core: add per-cell post processing

[Michael Walle]

Instead of relying on the name the consumer is using for the cell, like
it is done for the nvmem .cell_post_process configuration parameter,
provide a per-cell post processing hook. This can then be populated by
the NVMEM provider (or the NVMEM layout) when adding the cell.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - rename hook to read_post_process

 drivers/nvmem/core.c           | 17 +++++++++++++++++
 include/linux/nvmem-provider.h |  3 +++
 2 files changed, 20 insertions(+)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 87ba1e3a5bd4..e75642a675ae 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -53,6 +53,7 @@ struct nvmem_cell_entry {
 	int			bytes;
 	int			bit_offset;
 	int			nbits;
+	nvmem_cell_post_process_t read_post_process;
 	struct device_node	*np;
 	struct nvmem_device	*nvmem;
 	struct list_head	node;
@@ -469,6 +470,7 @@ static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 	cell->offset = info->offset;
 	cell->bytes = info->bytes;
 	cell->name = info->name;
+	cell->read_post_process = info->read_post_process;
 
 	cell->bit_offset = info->bit_offset;
 	cell->nbits = info->nbits;
@@ -1557,6 +1559,13 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
 	if (cell->bit_offset || cell->nbits)
 		nvmem_shift_read_buffer_in_place(cell, buf);
 
+	if (cell->read_post_process) {
+		rc = cell->read_post_process(nvmem->priv, id, index,
+					     cell->offset, buf, cell->bytes);
+		if (rc)
+			return rc;
+	}
+
 	if (nvmem->cell_post_process) {
 		rc = nvmem->cell_post_process(nvmem->priv, id, index,
 					      cell->offset, buf, cell->bytes);
@@ -1665,6 +1674,14 @@ static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, si
 	    (cell->bit_offset == 0 && len != cell->bytes))
 		return -EINVAL;
 
+	/*
+	 * Any cells which have a read_post_process hook are read-only because
+	 * we cannot reverse the operation and it might affect other cells,
+	 * too.
+	 */
+	if (cell->read_post_process)
+		return -EINVAL;
+
 	if (cell->bit_offset || cell->nbits) {
 		buf = nvmem_cell_prepare_write_buffer(cell, buf, len);
 		if (IS_ERR(buf))
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 4185767c114f..1930496d8854 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -54,6 +54,8 @@ struct nvmem_keepout {
  * @bit_offset:	Bit offset if cell is smaller than a byte.
  * @nbits:	Number of bits.
  * @np:		Optional device_node pointer.
+ * @read_post_process:	Callback for optional post processing of cell data
+ *			on reads.
  */
 struct nvmem_cell_info {
 	const char		*name;
@@ -62,6 +64,7 @@ struct nvmem_cell_info {
 	unsigned int		bit_offset;
 	unsigned int		nbits;
 	struct device_node	*np;
+	nvmem_cell_post_process_t read_post_process;
 };
 
 /**
-- 
2.30.2

[PATCH v4 13/20] nvmem: core: allow to modify a cell before adding it

[Michael Walle]

Provide a way to modify a cell before it will get added. This is useful
to attach a custom post processing hook via a layout.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - new patch

 drivers/nvmem/core.c           | 4 ++++
 include/linux/nvmem-provider.h | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index e75642a675ae..ccbde9629f7f 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -694,6 +694,7 @@ static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 
 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 {
+	struct nvmem_layout *layout = nvmem->layout;
 	struct device *dev = &nvmem->dev;
 	struct nvmem_cell_entry *cell;
 	struct device_node *child;
@@ -730,6 +731,9 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 
 		info.np = of_node_get(child);
 
+		if (layout && layout->fixup_cell_info)
+			layout->fixup_cell_info(nvmem, layout, &info);
+
 		ret = nvmem_add_one_cell(nvmem, &info);
 		kfree(info.name);
 		if (ret) {
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 1930496d8854..bfaba5227ac9 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -157,6 +157,8 @@ struct nvmem_cell_table {
  * @add_cells:		Will be called if a nvmem device is found which
  *			has this layout. The function will add layout
  *			specific cells with nvmem_add_one_cell().
+ * @fixup_cell_info:	Will be called before a cell is added. Can be
+ *			used to modify the nvmem_cell_info.
  * @owner:		Pointer to struct module.
  * @node:		List node.
  *
@@ -170,6 +172,9 @@ struct nvmem_layout {
 	const struct of_device_id *of_match_table;
 	int (*add_cells)(struct device *dev, struct nvmem_device *nvmem,
 			 struct nvmem_layout *layout);
+	void (*fixup_cell_info)(struct nvmem_device *nvmem,
+				struct nvmem_layout *layout,
+				struct nvmem_cell_info *cell);
 
 	/* private */
 	struct module *owner;
-- 
2.30.2

[PATCH v4 14/20] nvmem: imx-ocotp: replace global post processing with layouts

[Michael Walle]

In preparation of retiring the global post processing hook change this
driver to use layouts. The layout will be supplied during registration
and will be used to add the post processing hook to all added cells.

Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Michael Walle <michael@walle.cc> # on kontron-pitx-imx8m
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - new patch

 drivers/nvmem/imx-ocotp.c | 30 +++++++++++++++++++-----------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
index e9b52ecb3f72..ac0edb6398f1 100644
--- a/drivers/nvmem/imx-ocotp.c
+++ b/drivers/nvmem/imx-ocotp.c
@@ -225,18 +225,13 @@ static int imx_ocotp_read(void *context, unsigned int offset,
 static int imx_ocotp_cell_pp(void *context, const char *id, int index,
 			     unsigned int offset, void *data, size_t bytes)
 {
-	struct ocotp_priv *priv = context;
+	u8 *buf = data;
+	int i;
 
 	/* Deal with some post processing of nvmem cell data */
-	if (id && !strcmp(id, "mac-address")) {
-		if (priv->params->reverse_mac_address) {
-			u8 *buf = data;
-			int i;
-
-			for (i = 0; i < bytes/2; i++)
-				swap(buf[i], buf[bytes - i - 1]);
-		}
-	}
+	if (id && !strcmp(id, "mac-address"))
+		for (i = 0; i < bytes / 2; i++)
+			swap(buf[i], buf[bytes - i - 1]);
 
 	return 0;
 }
@@ -488,7 +483,6 @@ static struct nvmem_config imx_ocotp_nvmem_config = {
 	.stride = 1,
 	.reg_read = imx_ocotp_read,
 	.reg_write = imx_ocotp_write,
-	.cell_post_process = imx_ocotp_cell_pp,
 };
 
 static const struct ocotp_params imx6q_params = {
@@ -595,6 +589,17 @@ static const struct of_device_id imx_ocotp_dt_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, imx_ocotp_dt_ids);
 
+static void imx_ocotp_fixup_cell_info(struct nvmem_device *nvmem,
+				      struct nvmem_layout *layout,
+				      struct nvmem_cell_info *cell)
+{
+	cell->read_post_process = imx_ocotp_cell_pp;
+}
+
+struct nvmem_layout imx_ocotp_layout = {
+	.fixup_cell_info = imx_ocotp_fixup_cell_info,
+};
+
 static int imx_ocotp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -619,6 +624,9 @@ static int imx_ocotp_probe(struct platform_device *pdev)
 	imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
 	imx_ocotp_nvmem_config.dev = dev;
 	imx_ocotp_nvmem_config.priv = priv;
+	if (priv->params->reverse_mac_address)
+		imx_ocotp_nvmem_config.layout = &imx_ocotp_layout;
+
 	priv->config = &imx_ocotp_nvmem_config;
 
 	clk_prepare_enable(priv->clk);
-- 
2.30.2

[PATCH v4 15/20] nvmem: cell: drop global cell_post_process

[Michael Walle]

There are no users anymore for the global cell_post_process callback
anymore. New users should use proper nvmem layouts.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - none

changes since v1:
 - new patch

 drivers/nvmem/core.c           | 9 ---------
 include/linux/nvmem-provider.h | 2 --
 2 files changed, 11 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index ccbde9629f7f..5733bf79dda1 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -38,7 +38,6 @@ struct nvmem_device {
 	unsigned int		nkeepout;
 	nvmem_reg_read_t	reg_read;
 	nvmem_reg_write_t	reg_write;
-	nvmem_cell_post_process_t cell_post_process;
 	struct gpio_desc	*wp_gpio;
 	struct nvmem_layout	*layout;
 	void *priv;
@@ -899,7 +898,6 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
 	nvmem->type = config->type;
 	nvmem->reg_read = config->reg_read;
 	nvmem->reg_write = config->reg_write;
-	nvmem->cell_post_process = config->cell_post_process;
 	nvmem->keepout = config->keepout;
 	nvmem->nkeepout = config->nkeepout;
 	if (config->of_node)
@@ -1570,13 +1568,6 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
 			return rc;
 	}
 
-	if (nvmem->cell_post_process) {
-		rc = nvmem->cell_post_process(nvmem->priv, id, index,
-					      cell->offset, buf, cell->bytes);
-		if (rc)
-			return rc;
-	}
-
 	if (len)
 		*len = cell->bytes;
 
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index bfaba5227ac9..12833fe4eb4d 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -85,7 +85,6 @@ struct nvmem_cell_info {
  * @no_of_node:	Device should not use the parent's of_node even if it's !NULL.
  * @reg_read:	Callback to read data.
  * @reg_write:	Callback to write data.
- * @cell_post_process:	Callback for vendor specific post processing of cell data
  * @size:	Device size.
  * @word_size:	Minimum read/write access granularity.
  * @stride:	Minimum read/write access stride.
@@ -120,7 +119,6 @@ struct nvmem_config {
 	bool			no_of_node;
 	nvmem_reg_read_t	reg_read;
 	nvmem_reg_write_t	reg_write;
-	nvmem_cell_post_process_t cell_post_process;
 	int	size;
 	int	word_size;
 	int	stride;
-- 
2.30.2

[PATCH v4 16/20] nvmem: core: provide own priv pointer in post process callback

[Michael Walle]

It doesn't make any more sense to have a opaque pointer set up by the
nvmem device. Usually, the layout isn't associated with a particular
nvmem device. Instead, let the caller who set the post process callback
provide the priv pointer.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - don't drop the pointer but let the user specify an opaque pointer

changes since v1:
 - new patch

 drivers/nvmem/core.c           | 4 +++-
 include/linux/nvmem-provider.h | 5 ++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 5733bf79dda1..a52c810e9b02 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -53,6 +53,7 @@ struct nvmem_cell_entry {
 	int			bit_offset;
 	int			nbits;
 	nvmem_cell_post_process_t read_post_process;
+	void			*priv;
 	struct device_node	*np;
 	struct nvmem_device	*nvmem;
 	struct list_head	node;
@@ -470,6 +471,7 @@ static int nvmem_cell_info_to_nvmem_cell_entry_nodup(struct nvmem_device *nvmem,
 	cell->bytes = info->bytes;
 	cell->name = info->name;
 	cell->read_post_process = info->read_post_process;
+	cell->priv = info->priv;
 
 	cell->bit_offset = info->bit_offset;
 	cell->nbits = info->nbits;
@@ -1562,7 +1564,7 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
 		nvmem_shift_read_buffer_in_place(cell, buf);
 
 	if (cell->read_post_process) {
-		rc = cell->read_post_process(nvmem->priv, id, index,
+		rc = cell->read_post_process(cell->priv, id, index,
 					     cell->offset, buf, cell->bytes);
 		if (rc)
 			return rc;
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 12833fe4eb4d..cb0814f2ddae 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -20,7 +20,8 @@ typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
 				 void *val, size_t bytes);
 /* used for vendor specific post processing of cell data */
 typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,
-					 unsigned int offset, void *buf, size_t bytes);
+					 unsigned int offset, void *buf,
+					 size_t bytes);
 
 enum nvmem_type {
 	NVMEM_TYPE_UNKNOWN = 0,
@@ -56,6 +57,7 @@ struct nvmem_keepout {
  * @np:		Optional device_node pointer.
  * @read_post_process:	Callback for optional post processing of cell data
  *			on reads.
+ * @priv:	Opaque data passed to the read_post_process hook.
  */
 struct nvmem_cell_info {
 	const char		*name;
@@ -65,6 +67,7 @@ struct nvmem_cell_info {
 	unsigned int		nbits;
 	struct device_node	*np;
 	nvmem_cell_post_process_t read_post_process;
+	void			*priv;
 };
 
 /**
-- 
2.30.2

[PATCH v4 17/20] nvmem: layouts: add sl28vpd layout

[Michael Walle]

This layout applies to the VPD of the Kontron sl28 boards. The VPD only
contains a base MAC address. Therefore, we have to add an individual
offset to it. This is done by taking the second argument of the nvmem
phandle into account. Also this let us checking the VPD version and the
checksum.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - use of_nvmem_layout_get_container()

changes since v1:
 - none

 drivers/nvmem/layouts/Kconfig   |   9 ++
 drivers/nvmem/layouts/Makefile  |   2 +
 drivers/nvmem/layouts/sl28vpd.c | 153 ++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 drivers/nvmem/layouts/sl28vpd.c

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 9ad3911d1605..75082f6b471d 100644
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -2,4 +2,13 @@
 
 menu "Layout Types"
 
+config NVMEM_LAYOUT_SL28_VPD
+	bool "Kontron sl28 VPD layout support"
+	select CRC8
+	help
+	  Say Y here if you want to support the VPD layout of the Kontron
+	  SMARC-sAL28 boards.
+
+	  If unsure, say N.
+
 endmenu
diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile
index 6fdb3c60a4fa..fc617b9e87d0 100644
--- a/drivers/nvmem/layouts/Makefile
+++ b/drivers/nvmem/layouts/Makefile
@@ -2,3 +2,5 @@
 #
 # Makefile for nvmem layouts.
 #
+
+obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o
diff --git a/drivers/nvmem/layouts/sl28vpd.c b/drivers/nvmem/layouts/sl28vpd.c
new file mode 100644
index 000000000000..a36800f201a3
--- /dev/null
+++ b/drivers/nvmem/layouts/sl28vpd.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/crc8.h>
+#include <linux/etherdevice.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <uapi/linux/if_ether.h>
+
+#define SL28VPD_MAGIC 'V'
+
+struct sl28vpd_header {
+	u8 magic;
+	u8 version;
+} __packed;
+
+struct sl28vpd_v1 {
+	struct sl28vpd_header header;
+	char serial_number[15];
+	u8 base_mac_address[ETH_ALEN];
+	u8 crc8;
+} __packed;
+
+static int sl28vpd_mac_address_pp(void *priv, const char *id, int index,
+				  unsigned int offset, void *buf,
+				  size_t bytes)
+{
+	if (bytes != ETH_ALEN)
+		return -EINVAL;
+
+	if (index < 0)
+		return -EINVAL;
+
+	if (!is_valid_ether_addr(buf))
+		return -EINVAL;
+
+	eth_addr_add(buf, index);
+
+	return 0;
+}
+
+static const struct nvmem_cell_info sl28vpd_v1_entries[] = {
+	{
+		.name = "serial-number",
+		.offset = offsetof(struct sl28vpd_v1, serial_number),
+		.bytes = sizeof_field(struct sl28vpd_v1, serial_number),
+	},
+	{
+		.name = "base-mac-address",
+		.offset = offsetof(struct sl28vpd_v1, base_mac_address),
+		.bytes = sizeof_field(struct sl28vpd_v1, base_mac_address),
+		.read_post_process = sl28vpd_mac_address_pp,
+	},
+};
+
+static int sl28vpd_v1_check_crc(struct device *dev, struct nvmem_device *nvmem)
+{
+	struct sl28vpd_v1 data_v1;
+	u8 table[CRC8_TABLE_SIZE];
+	int ret;
+	u8 crc;
+
+	crc8_populate_msb(table, 0x07);
+
+	ret = nvmem_device_read(nvmem, 0, sizeof(data_v1), &data_v1);
+	if (ret < 0)
+		return ret;
+	else if (ret != sizeof(data_v1))
+		return -EIO;
+
+	crc = crc8(table, (void *)&data_v1, sizeof(data_v1) - 1, 0);
+
+	if (crc != data_v1.crc8) {
+		dev_err(dev,
+			"Checksum is invalid (got %02x, expected %02x).\n",
+			crc, data_v1.crc8);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sl28vpd_add_cells(struct device *dev, struct nvmem_device *nvmem,
+			     struct nvmem_layout *layout)
+{
+	const struct nvmem_cell_info *pinfo;
+	struct nvmem_cell_info info = {0};
+	struct device_node *layout_np;
+	struct sl28vpd_header hdr;
+	int ret, i;
+
+	/* check header */
+	ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
+	if (ret < 0)
+		return ret;
+	else if (ret != sizeof(hdr))
+		return -EIO;
+
+	if (hdr.magic != SL28VPD_MAGIC) {
+		dev_err(dev, "Invalid magic value (%02x)\n", hdr.magic);
+		return -EINVAL;
+	}
+
+	if (hdr.version != 1) {
+		dev_err(dev, "Version %d is unsupported.\n", hdr.version);
+		return -EINVAL;
+	}
+
+	ret = sl28vpd_v1_check_crc(dev, nvmem);
+	if (ret)
+		return ret;
+
+	layout_np = of_nvmem_layout_get_container(nvmem);
+	if (!layout_np)
+		return -ENOENT;
+
+	for (i = 0; i < ARRAY_SIZE(sl28vpd_v1_entries); i++) {
+		pinfo = &sl28vpd_v1_entries[i];
+
+		info.name = pinfo->name;
+		info.offset = pinfo->offset;
+		info.bytes = pinfo->bytes;
+		info.read_post_process = pinfo->read_post_process;
+		info.np = of_get_child_by_name(layout_np, pinfo->name);
+
+		ret = nvmem_add_one_cell(nvmem, &info);
+		if (ret) {
+			of_node_put(layout_np);
+			return ret;
+		}
+	}
+
+	of_node_put(layout_np);
+
+	return 0;
+}
+
+static const struct of_device_id sl28vpd_of_match_table[] = {
+	{ .compatible = "kontron,sl28-vpd" },
+	{},
+};
+
+struct nvmem_layout sl28vpd_layout = {
+	.name = "sl28-vpd",
+	.of_match_table = sl28vpd_of_match_table,
+	.add_cells = sl28vpd_add_cells,
+};
+
+static int __init sl28vpd_init(void)
+{
+	return nvmem_layout_register(&sl28vpd_layout);
+}
+subsys_initcall(sl28vpd_init);
-- 
2.30.2

[PATCH v4 18/20] MAINTAINERS: add myself as sl28vpd nvmem layout driver

[Michael Walle]

Add myself as a maintainer for the new sl28vpd nvmem layout driver.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v3:
 - none

changes since v2:
 - new patch

 MAINTAINERS | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 36ff8badc6bb..0e0cc35d90b7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -19103,6 +19103,12 @@ F:	drivers/irqchip/irq-sl28cpld.c
 F:	drivers/pwm/pwm-sl28cpld.c
 F:	drivers/watchdog/sl28cpld_wdt.c
 
+SL28 VPD NVMEM LAYOUT DRIVER
+M:	Michael Walle <michael@walle.cc>
+S:	Maintained
+F:	Documentation/devicetree/bindings/nvmem/layouts/kontron,sl28-vpd.yaml
+F:	drivers/nvmem/layouts/sl28vpd.c
+
 SLAB ALLOCATOR
 M:	Christoph Lameter <cl@linux.com>
 M:	Pekka Enberg <penberg@kernel.org>
-- 
2.30.2

[PATCH v4 19/20] nvmem: layouts: Add ONIE tlv layout driver

[Michael Walle]

From: Miquel Raynal <miquel.raynal@bootlin.com>

This layout applies on top of any non volatile storage device containing
an ONIE table factory flashed. This table follows the tlv
(type-length-value) organization described in the link below. We cannot
afford using regular parsers because the content of these tables is
manufacturer specific and must be dynamically discovered.

Link: https://opencomputeproject.github.io/onie/design-spec/hw_requirements.html
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
changes since v3:
 - don't use kfree()
 - fix typo, s/no/on/

changes since v2:
 - new patch

 drivers/nvmem/layouts/Kconfig    |   9 ++
 drivers/nvmem/layouts/Makefile   |   1 +
 drivers/nvmem/layouts/onie-tlv.c | 244 +++++++++++++++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 drivers/nvmem/layouts/onie-tlv.c

diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig
index 75082f6b471d..9ad50474cb77 100644
--- a/drivers/nvmem/layouts/Kconfig
+++ b/drivers/nvmem/layouts/Kconfig
@@ -11,4 +11,13 @@ config NVMEM_LAYOUT_SL28_VPD
 
 	  If unsure, say N.
 
+config NVMEM_LAYOUT_ONIE_TLV
+	bool "ONIE tlv support"
+	select CRC32
+	help
+	  Say Y here if you want to support the Open Compute Project ONIE
+	  Type-Length-Value standard table.
+
+	  If unsure, say N.
+
 endmenu
diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile
index fc617b9e87d0..2974bd7d33ed 100644
--- a/drivers/nvmem/layouts/Makefile
+++ b/drivers/nvmem/layouts/Makefile
@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_NVMEM_LAYOUT_SL28_VPD) += sl28vpd.o
+obj-$(CONFIG_NVMEM_LAYOUT_ONIE_TLV) += onie-tlv.o
diff --git a/drivers/nvmem/layouts/onie-tlv.c b/drivers/nvmem/layouts/onie-tlv.c
new file mode 100644
index 000000000000..074c7c700845
--- /dev/null
+++ b/drivers/nvmem/layouts/onie-tlv.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ONIE tlv NVMEM cells provider
+ *
+ * Copyright (C) 2022 Open Compute Group ONIE
+ * Author: Miquel Raynal <miquel.raynal@bootlin.com>
+ * Based on the nvmem driver written by: Vadym Kochan <vadym.kochan@plvision.eu>
+ * Inspired by the first layout written by: Rafał Miłecki <rafal@milecki.pl>
+ */
+
+#include <linux/crc32.h>
+#include <linux/etherdevice.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+
+#define ONIE_TLV_MAX_LEN 2048
+#define ONIE_TLV_CRC_FIELD_SZ 6
+#define ONIE_TLV_CRC_SZ 4
+#define ONIE_TLV_HDR_ID	"TlvInfo"
+
+struct onie_tlv_hdr {
+	u8 id[8];
+	u8 version;
+	__be16 data_len;
+} __packed;
+
+struct onie_tlv {
+	u8 type;
+	u8 len;
+} __packed;
+
+static const char *onie_tlv_cell_name(u8 type)
+{
+	switch (type) {
+	case 0x21:
+		return "product-name";
+	case 0x22:
+		return "part-number";
+	case 0x23:
+		return "serial-number";
+	case 0x24:
+		return "mac-address";
+	case 0x25:
+		return "manufacture-date";
+	case 0x26:
+		return "device-version";
+	case 0x27:
+		return "label-revision";
+	case 0x28:
+		return "platforn-name";
+	case 0x29:
+		return "onie-version";
+	case 0x2A:
+		return "num-macs";
+	case 0x2B:
+		return "manufacturer";
+	case 0x2C:
+		return "country-code";
+	case 0x2D:
+		return "vendor";
+	case 0x2E:
+		return "diag-version";
+	case 0x2F:
+		return "service-tag";
+	case 0xFD:
+		return "vendor-extension";
+	case 0xFE:
+		return "crc32";
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static int onie_tlv_mac_read_cb(void *priv, const char *id, int index,
+				unsigned int offset, void *buf,
+				size_t bytes)
+{
+	eth_addr_add(buf, index);
+
+	return 0;
+}
+
+static nvmem_cell_post_process_t onie_tlv_read_cb(u8 type, u8 *buf)
+{
+	switch (type) {
+	case 0x24:
+		return &onie_tlv_mac_read_cb;
+	default:
+		break;
+	}
+
+	return NULL;
+}
+
+static int onie_tlv_add_cells(struct device *dev, struct nvmem_device *nvmem,
+			      size_t data_len, u8 *data)
+{
+	struct nvmem_cell_info cell = {};
+	struct device_node *layout;
+	struct onie_tlv tlv;
+	unsigned int hdr_len = sizeof(struct onie_tlv_hdr);
+	unsigned int offset = 0;
+	int ret;
+
+	layout = of_nvmem_layout_get_container(nvmem);
+	if (!layout)
+		return -ENOENT;
+
+	while (offset < data_len) {
+		memcpy(&tlv, data + offset, sizeof(tlv));
+		if (offset + tlv.len >= data_len) {
+			dev_err(dev, "Out of bounds field (0x%x bytes at 0x%x)\n",
+				tlv.len, hdr_len + offset);
+			break;
+		}
+
+		cell.name = onie_tlv_cell_name(tlv.type);
+		if (!cell.name)
+			continue;
+
+		cell.offset = hdr_len + offset + sizeof(tlv.type) + sizeof(tlv.len);
+		cell.bytes = tlv.len;
+		cell.np = of_get_child_by_name(layout, cell.name);
+		cell.read_post_process = onie_tlv_read_cb(tlv.type, data + offset + sizeof(tlv));
+
+		ret = nvmem_add_one_cell(nvmem, &cell);
+		if (ret) {
+			of_node_put(layout);
+			return ret;
+		}
+
+		offset += sizeof(tlv) + tlv.len;
+	}
+
+	of_node_put(layout);
+
+	return 0;
+}
+
+static bool onie_tlv_hdr_is_valid(struct device *dev, struct onie_tlv_hdr *hdr)
+{
+	if (memcmp(hdr->id, ONIE_TLV_HDR_ID, sizeof(hdr->id))) {
+		dev_err(dev, "Invalid header\n");
+		return false;
+	}
+
+	if (hdr->version != 0x1) {
+		dev_err(dev, "Invalid version number\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool onie_tlv_crc_is_valid(struct device *dev, size_t table_len, u8 *table)
+{
+	struct onie_tlv crc_hdr;
+	u32 read_crc, calc_crc;
+	__be32 crc_be;
+
+	memcpy(&crc_hdr, table + table_len - ONIE_TLV_CRC_FIELD_SZ, sizeof(crc_hdr));
+	if (crc_hdr.type != 0xfe || crc_hdr.len != ONIE_TLV_CRC_SZ) {
+		dev_err(dev, "Invalid CRC field\n");
+		return false;
+	}
+
+	/* The table contains a JAMCRC, which is XOR'ed compared to the original
+	 * CRC32 implementation as known in the Ethernet world.
+	 */
+	memcpy(&crc_be, table + table_len - ONIE_TLV_CRC_SZ, ONIE_TLV_CRC_SZ);
+	read_crc = be32_to_cpu(crc_be);
+	calc_crc = crc32(~0, table, table_len - ONIE_TLV_CRC_SZ) ^ 0xFFFFFFFF;
+	if (read_crc != calc_crc) {
+		dev_err(dev, "Invalid CRC read: 0x%08x, expected: 0x%08x\n",
+			read_crc, calc_crc);
+		return false;
+	}
+
+	return true;
+}
+
+static int onie_tlv_parse_table(struct device *dev, struct nvmem_device *nvmem,
+				struct nvmem_layout *layout)
+{
+	struct onie_tlv_hdr hdr;
+	size_t table_len, data_len, hdr_len;
+	u8 *table, *data;
+	int ret;
+
+	ret = nvmem_device_read(nvmem, 0, sizeof(hdr), &hdr);
+	if (ret < 0)
+		return ret;
+
+	if (!onie_tlv_hdr_is_valid(dev, &hdr)) {
+		dev_err(dev, "Invalid ONIE TLV header\n");
+		return -EINVAL;
+	}
+
+	hdr_len = sizeof(hdr.id) + sizeof(hdr.version) + sizeof(hdr.data_len);
+	data_len = be16_to_cpu(hdr.data_len);
+	table_len = hdr_len + data_len;
+	if (table_len > ONIE_TLV_MAX_LEN) {
+		dev_err(dev, "Invalid ONIE TLV data length\n");
+		return -EINVAL;
+	}
+
+	table = devm_kmalloc(dev, table_len, GFP_KERNEL);
+	if (!table)
+		return -ENOMEM;
+
+	ret = nvmem_device_read(nvmem, 0, table_len, table);
+	if (ret != table_len)
+		return ret;
+
+	if (!onie_tlv_crc_is_valid(dev, table_len, table))
+		return -EINVAL;
+
+	data = table + hdr_len;
+	ret = onie_tlv_add_cells(dev, nvmem, data_len, data);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id onie_tlv_of_match_table[] = {
+	{ .compatible = "onie,tlv-layout", },
+	{},
+};
+
+static struct nvmem_layout onie_tlv_layout = {
+	.name = "ONIE tlv layout",
+	.of_match_table = onie_tlv_of_match_table,
+	.add_cells = onie_tlv_parse_table,
+};
+
+static int __init onie_tlv_init(void)
+{
+	return nvmem_layout_register(&onie_tlv_layout);
+}
+subsys_initcall(onie_tlv_init);
-- 
2.30.2

[PATCH v4 20/20] MAINTAINERS: Add myself as ONIE tlv NVMEM layout maintainer

[Michael Walle]

From: Miquel Raynal <miquel.raynal@bootlin.com>

Following the introduction of the bindings for this NVMEM parser and the
layout driver, add myself as maintainer.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
changes since v3:
 - none

changes since v2:
 - new patch

 MAINTAINERS | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 0e0cc35d90b7..22abbbcf42c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15507,6 +15507,12 @@ L:	linux-hwmon@vger.kernel.org
 S:	Maintained
 F:	drivers/hwmon/oxp-sensors.c
 
+ONIE TLV NVMEM LAYOUT DRIVER
+M:	Miquel Raynal <miquel.raynal@bootlin.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/nvmem/layouts/onie,tlv-layout.yaml
+F:	drivers/nvmem/layouts/onie-tlv.c
+
 ONION OMEGA2+ BOARD
 M:	Harvey Hunt <harveyhuntnexus@gmail.com>
 L:	linux-mips@vger.kernel.org
-- 
2.30.2