+++ /dev/null
-From 266570f496b90dea8fda893c2cf7c28d63ae2bd9 Mon Sep 17 00:00:00 2001
-From: Michael Walle <michael@walle.cc>
-Date: Tue, 4 Apr 2023 18:21:21 +0100
-Subject: [PATCH] nvmem: core: introduce NVMEM layouts
-
-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>
-Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
-Link: https://lore.kernel.org/r/20230404172148.82422-14-srinivas.kandagatla@linaro.org
-Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
----
- Documentation/driver-api/nvmem.rst | 15 ++++
- drivers/nvmem/Kconfig | 4 +
- drivers/nvmem/Makefile | 1 +
- drivers/nvmem/core.c | 120 +++++++++++++++++++++++++++++
- 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, 207 insertions(+)
- create mode 100644 drivers/nvmem/layouts/Kconfig
- create mode 100644 drivers/nvmem/layouts/Makefile
-
---- a/Documentation/driver-api/nvmem.rst
-+++ b/Documentation/driver-api/nvmem.rst
-@@ -189,3 +189,18 @@ 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.
---- 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
---- 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
---- 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)
- {
-@@ -728,6 +732,101 @@ static int nvmem_add_cells_from_of(struc
- 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)
-+{
-+ struct device_node __maybe_unused *layout_np;
-+ const struct of_device_id *match;
-+
-+ layout_np = of_nvmem_layout_get_container(nvmem);
-+ match = of_match_node(layout->of_match_table, layout_np);
-+
-+ 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
-@@ -834,6 +933,12 @@ struct nvmem_device *nvmem_register(cons
- goto err_put_device;
- }
-
-+ /*
-+ * 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)
-@@ -854,12 +959,17 @@ struct nvmem_device *nvmem_register(cons
- 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;
-
- err_remove_cells:
- nvmem_device_remove_all_cells(nvmem);
-+ nvmem_layout_put(nvmem->layout);
- if (config->compat)
- nvmem_sysfs_remove_compat(nvmem, config);
- err_put_device:
-@@ -881,6 +991,7 @@ static void nvmem_device_release(struct
- device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
-
- nvmem_device_remove_all_cells(nvmem);
-+ nvmem_layout_put(nvmem->layout);
- device_unregister(&nvmem->dev);
- }
-
-@@ -1246,6 +1357,15 @@ struct nvmem_cell *of_nvmem_cell_get(str
- 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)) {
---- /dev/null
-+++ b/drivers/nvmem/layouts/Kconfig
-@@ -0,0 +1,5 @@
-+# SPDX-License-Identifier: GPL-2.0
-+
-+menu "Layout Types"
-+
-+endmenu
---- /dev/null
-+++ b/drivers/nvmem/layouts/Makefile
-@@ -0,0 +1,4 @@
-+# SPDX-License-Identifier: GPL-2.0
-+#
-+# Makefile for nvmem layouts.
-+#
---- a/include/linux/nvmem-consumer.h
-+++ b/include/linux/nvmem-consumer.h
-@@ -225,6 +225,7 @@ struct nvmem_cell *of_nvmem_cell_get(str
- 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)
-@@ -237,6 +238,12 @@ static inline struct nvmem_device *of_nv
- {
- 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 */
---- a/include/linux/nvmem-provider.h
-+++ b/include/linux/nvmem-provider.h
-@@ -88,6 +88,7 @@ struct nvmem_cell_info {
- * @stride: Minimum read/write access stride.
- * @priv: User context passed to read/write callbacks.
- * @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
-@@ -110,6 +111,7 @@ struct nvmem_config {
- bool root_only;
- struct device_node *of_node;
- bool ignore_wp;
-+ struct nvmem_layout *layout;
- bool no_of_node;
- nvmem_reg_read_t reg_read;
- nvmem_reg_write_t reg_write;
-@@ -142,6 +144,33 @@ 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);
-@@ -156,6 +185,14 @@ void nvmem_del_cell_table(struct nvmem_c
- 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)
-@@ -179,5 +216,19 @@ static inline int nvmem_add_one_cell(str
- 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 */
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