F: include/nvme.h
F: doc/develop/driver-model/nvme.rst
+NVMEM
+M: Sean Anderson <seanga2@gmail.com>
+S: Maintained
+F: doc/api/nvmem.rst
+F: drivers/misc/nvmem.c
+F: include/nvmem.h
+
NXP C45 TJA11XX PHY DRIVER
M: Radu Pirea <radu-nicolae.pirea@oss.nxp.com>
S: Maintained
linker_lists
lmb
logging
+ nvmem
pinctrl
rng
sandbox
--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0+
+
+NVMEM API
+=========
+
+.. kernel-doc:: include/nvmem.h
+ :doc: Design
+
+.. kernel-doc:: include/nvmem.h
+ :internal:
set of generic read, write and ioctl methods may be used to
access the device.
+config NVMEM
+ bool "NVMEM support"
+ help
+ This adds support for a common interface to different types of
+ non-volatile memory. Consumers can use nvmem-cells properties to look
+ up hardware configuration data such as MAC addresses and calibration
+ settings.
+
+config SPL_NVMEM
+ bool "NVMEM support in SPL"
+ help
+ This adds support for a common interface to different types of
+ non-volatile memory. Consumers can use nvmem-cells properties to look
+ up hardware configuration data such as MAC addresses and calibration
+ settings.
+
config ALTERA_SYSID
bool "Altera Sysid support"
depends on MISC
# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
obj-$(CONFIG_$(SPL_TPL_)MISC) += misc-uclass.o
+obj-$(CONFIG_$(SPL_TPL_)NVMEM) += nvmem.o
obj-$(CONFIG_$(SPL_TPL_)CROS_EC) += cros_ec.o
obj-$(CONFIG_$(SPL_TPL_)CROS_EC_SANDBOX) += cros_ec_sandbox.o
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
+ */
+
+#include <common.h>
+#include <i2c_eeprom.h>
+#include <linker_lists.h>
+#include <misc.h>
+#include <nvmem.h>
+#include <rtc.h>
+#include <dm/device_compat.h>
+#include <dm/ofnode.h>
+#include <dm/read.h>
+#include <dm/uclass.h>
+
+int nvmem_cell_read(struct nvmem_cell *cell, void *buf, size_t size)
+{
+ dev_dbg(cell->nvmem, "%s: off=%u size=%zu\n", __func__, cell->offset, size);
+ if (size != cell->size)
+ return -EINVAL;
+
+ switch (cell->nvmem->driver->id) {
+ case UCLASS_I2C_EEPROM:
+ return i2c_eeprom_read(cell->nvmem, cell->offset, buf, size);
+ case UCLASS_MISC: {
+ int ret = misc_read(cell->nvmem, cell->offset, buf, size);
+
+ if (ret < 0)
+ return ret;
+ if (ret != size)
+ return -EIO;
+ return 0;
+ }
+ case UCLASS_RTC:
+ return dm_rtc_read(cell->nvmem, cell->offset, buf, size);
+ default:
+ return -ENOSYS;
+ }
+}
+
+int nvmem_cell_write(struct nvmem_cell *cell, const void *buf, size_t size)
+{
+ dev_dbg(cell->nvmem, "%s: off=%u size=%zu\n", __func__, cell->offset, size);
+ if (size != cell->size)
+ return -EINVAL;
+
+ switch (cell->nvmem->driver->id) {
+ case UCLASS_I2C_EEPROM:
+ return i2c_eeprom_write(cell->nvmem, cell->offset, buf, size);
+ case UCLASS_MISC: {
+ int ret = misc_write(cell->nvmem, cell->offset, buf, size);
+
+ if (ret < 0)
+ return ret;
+ if (ret != size)
+ return -EIO;
+ return 0;
+ }
+ case UCLASS_RTC:
+ return dm_rtc_write(cell->nvmem, cell->offset, buf, size);
+ default:
+ return -ENOSYS;
+ }
+}
+
+/**
+ * nvmem_get_device() - Get an nvmem device for a cell
+ * @node: ofnode of the nvmem device
+ * @cell: Cell to look up
+ *
+ * Try to find a nvmem-compatible device by going through the nvmem interfaces.
+ *
+ * Return:
+ * * 0 on success
+ * * -ENODEV if we didn't find anything
+ * * A negative error if there was a problem looking up the device
+ */
+static int nvmem_get_device(ofnode node, struct nvmem_cell *cell)
+{
+ int i, ret;
+ enum uclass_id ids[] = {
+ UCLASS_I2C_EEPROM,
+ UCLASS_MISC,
+ UCLASS_RTC,
+ };
+
+ for (i = 0; i < ARRAY_SIZE(ids); i++) {
+ ret = uclass_get_device_by_ofnode(ids[i], node, &cell->nvmem);
+ if (!ret)
+ return 0;
+ if (ret != -ENODEV && ret != -EPFNOSUPPORT)
+ return ret;
+ }
+
+ return -ENODEV;
+}
+
+int nvmem_cell_get_by_index(struct udevice *dev, int index,
+ struct nvmem_cell *cell)
+{
+ fdt_addr_t offset;
+ fdt_size_t size = FDT_SIZE_T_NONE;
+ int ret;
+ struct ofnode_phandle_args args;
+
+ dev_dbg(dev, "%s: index=%d\n", __func__, index);
+
+ ret = dev_read_phandle_with_args(dev, "nvmem-cells", NULL, 0, index,
+ &args);
+ if (ret)
+ return ret;
+
+ ret = nvmem_get_device(ofnode_get_parent(args.node), cell);
+ if (ret)
+ return ret;
+
+ offset = ofnode_get_addr_size_index_notrans(args.node, 0, &size);
+ if (offset == FDT_ADDR_T_NONE || size == FDT_SIZE_T_NONE) {
+ dev_dbg(cell->nvmem, "missing address or size for %s\n",
+ ofnode_get_name(args.node));
+ return -EINVAL;
+ }
+
+ cell->offset = offset;
+ cell->size = size;
+ return 0;
+}
+
+int nvmem_cell_get_by_name(struct udevice *dev, const char *name,
+ struct nvmem_cell *cell)
+{
+ int index;
+
+ dev_dbg(dev, "%s, name=%s\n", __func__, name);
+
+ index = dev_read_stringlist_search(dev, "nvmem-cell-names", name);
+ if (index < 0)
+ return index;
+
+ return nvmem_cell_get_by_index(dev, index, cell);
+}
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2022 Sean Anderson <sean.anderson@seco.com>
+ */
+
+#ifndef NVMEM_H
+#define NVMEM_H
+
+/**
+ * DOC: Design
+ *
+ * The NVMEM subsystem is a "meta-uclass" in that it abstracts over several
+ * different uclasses all with read/write APIs. One approach to implementing
+ * this could be to add a new sub-device for each nvmem-style device of
+ * UCLASS_NVMEM. This subsystem has taken the approach of using the existing
+ * access methods (i2c_eeprom_write, misc_write, etc.) directly. This has the
+ * advantage of not requiring an extra device/driver, saving on binary size and
+ * runtime memory usage. On the other hand, it is not idiomatic. Similar
+ * efforts should generally use a new uclass.
+ */
+
+/**
+ * struct nvmem_cell - One datum within non-volatile memory
+ * @nvmem: The backing storage device
+ * @offset: The offset of the cell from the start of @nvmem
+ * @size: The size of the cell, in bytes
+ */
+struct nvmem_cell {
+ struct udevice *nvmem;
+ unsigned int offset;
+ size_t size;
+};
+
+struct udevice;
+
+#if CONFIG_IS_ENABLED(NVMEM)
+
+/**
+ * nvmem_cell_read() - Read the value of an nvmem cell
+ * @cell: The nvmem cell to read
+ * @buf: The buffer to read into
+ * @size: The size of @buf
+ *
+ * Return:
+ * * 0 on success
+ * * -EINVAL if @buf is not the same size as @cell.
+ * * -ENOSYS if CONFIG_NVMEM is disabled
+ * * A negative error if there was a problem reading the underlying storage
+ */
+int nvmem_cell_read(struct nvmem_cell *cell, void *buf, size_t size);
+
+/**
+ * nvmem_cell_write() - Write a value to an nvmem cell
+ * @cell: The nvmem cell to write
+ * @buf: The buffer to write from
+ * @size: The size of @buf
+ *
+ * Return:
+ * * 0 on success
+ * * -EINVAL if @buf is not the same size as @cell
+ * * -ENOSYS if @cell is read-only, or if CONFIG_NVMEM is disabled
+ * * A negative error if there was a problem writing the underlying storage
+ */
+int nvmem_cell_write(struct nvmem_cell *cell, const void *buf, size_t size);
+
+/**
+ * nvmem_cell_get_by_index() - Get an nvmem cell from a given device and index
+ * @dev: The device that uses the nvmem cell
+ * @index: The index of the cell in nvmem-cells
+ * @cell: The cell to initialize
+ *
+ * Look up the nvmem cell referenced by the phandle at @index in nvmem-cells in
+ * @dev.
+ *
+ * Return:
+ * * 0 on success
+ * * -EINVAL if the regs property is missing, empty, or undersized
+ * * -ENODEV if the nvmem device is missing or unimplemented
+ * * -ENOSYS if CONFIG_NVMEM is disabled
+ * * A negative error if there was a problem reading nvmem-cells or getting the
+ * device
+ */
+int nvmem_cell_get_by_index(struct udevice *dev, int index,
+ struct nvmem_cell *cell);
+
+/**
+ * nvmem_cell_get_by_name() - Get an nvmem cell from a given device and name
+ * @dev: The device that uses the nvmem cell
+ * @name: The name of the nvmem cell
+ * @cell: The cell to initialize
+ *
+ * Look up the nvmem cell referenced by @name in the nvmem-cell-names property
+ * of @dev.
+ *
+ * Return:
+ * * 0 on success
+ * * -EINVAL if the regs property is missing, empty, or undersized
+ * * -ENODEV if the nvmem device is missing or unimplemented
+ * * -ENODATA if @name is not in nvmem-cell-names
+ * * -ENOSYS if CONFIG_NVMEM is disabled
+ * * A negative error if there was a problem reading nvmem-cell-names,
+ * nvmem-cells, or getting the device
+ */
+int nvmem_cell_get_by_name(struct udevice *dev, const char *name,
+ struct nvmem_cell *cell);
+
+#else /* CONFIG_NVMEM */
+
+static inline int nvmem_cell_read(struct nvmem_cell *cell, void *buf, int size)
+{
+ return -ENOSYS;
+}
+
+static inline int nvmem_cell_write(struct nvmem_cell *cell, const void *buf,
+ int size)
+{
+ return -ENOSYS;
+}
+
+static inline int nvmem_cell_get_by_index(struct udevice *dev, int index,
+ struct nvmem_cell *cell)
+{
+ return -ENOSYS;
+}
+
+static inline int nvmem_cell_get_by_name(struct udevice *dev, const char *name,
+ struct nvmem_cell *cell)
+{
+ return -ENOSYS;
+}
+
+#endif /* CONFIG_NVMEM */
+
+#endif /* NVMEM_H */
projects / u-boot.git / commitdiff
