3 files changed, 159 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 419ddd31c0b..f368d52c561 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -43,6 +43,22 @@ config VPL_MISC
 	  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
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 7a6047f64f9..6c790308937 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -4,6 +4,7 @@
 # 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
diff --git a/drivers/misc/nvmem.c b/drivers/misc/nvmem.c
new file mode 100644
index 00000000000..5a2bd1f9f72
--- /dev/null
+++ b/drivers/misc/nvmem.c
@@ -0,0 +1,142 @@
+// 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);
+}