Add 'nvmem-blob' driver, which allows to access device tree embedded data via NVMEM subsystem API.
Signed-off-by: Andrey Smirnov <[email protected]> --- Documentation/devicetree/bindings/nvmem/blob.txt | 35 ++++++ drivers/nvmem/Makefile | 1 + drivers/nvmem/blob.c | 132 +++++++++++++++++++++++ 3 files changed, 168 insertions(+) create mode 100644 Documentation/devicetree/bindings/nvmem/blob.txt create mode 100644 drivers/nvmem/blob.c diff --git a/Documentation/devicetree/bindings/nvmem/blob.txt b/Documentation/devicetree/bindings/nvmem/blob.txt new file mode 100644 index 0000000..b299576 --- /dev/null +++ b/Documentation/devicetree/bindings/nvmem/blob.txt @@ -0,0 +1,35 @@ += Deviece Tree Embedded Blob As NVMEM Device = + +This binding is designed to provide a way for a developer to reference +data, built-in into device tree blob file, as NVMEM provider and acccess +certain portions of that data as NVMEM cells using NVMEM consumer API. + +Required properties: +- compatible: should be "nvmem-blob" +- data: specifies data contained in nvmem device + += Data cells = +Are child nodes of nvmem-composite, bindings of which as described in +bindings/nvmem/nvmem.txt + +Example: + + a-blob { + compatible = "nvmem-blob"; + data = [aa bb cc dd ee]; + + cell1: cell@0 { + reg = <0 5>; + }; + }; + += Data consumers = +Are device nodes which consume nvmem data cells. + +Example: + + a-node { + ... + nvmem-cells = <&cell1>; + nvmem-cell-names = "some-data"; + }; diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 95dde3f..1a1adba 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -18,3 +18,4 @@ obj-$(CONFIG_NVMEM_SUNXI_SID) += nvmem_sunxi_sid.o nvmem_sunxi_sid-y := sunxi_sid.o obj-$(CONFIG_NVMEM_VF610_OCOTP) += nvmem-vf610-ocotp.o nvmem-vf610-ocotp-y := vf610-ocotp.o +obj-y += blob.o diff --git a/drivers/nvmem/blob.c b/drivers/nvmem/blob.c new file mode 100644 index 0000000..3f2296b --- /dev/null +++ b/drivers/nvmem/blob.c @@ -0,0 +1,132 @@ +#define DEBUG 1 + +#include <linux/device.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +struct nvmem_blob { + const u8 *data; + size_t data_size; +}; + +static int nvmem_blob_write(void *context, const void *data, + size_t count) +{ + return -ENOTSUPP; +} + +static int nvmem_blob_read(void *context, + const void *reg, size_t reg_size, + void *val, size_t val_size) +{ + struct nvmem_blob *nblob = context; + const unsigned int offset = *(u32 *)reg; + + memcpy(val, nblob->data + offset, + min(val_size, nblob->data_size - offset)); + return 0; +} + +static const struct regmap_bus nvmem_blob_regmap_bus = { + .write = nvmem_blob_write, + .read = nvmem_blob_read, +}; + + +static int nvmem_blob_validate_dt(struct device_node *np) +{ + return 0; +} + +static int nvmem_blob_probe(struct platform_device *pdev) +{ + int ret; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct regmap *map; + struct nvmem_device *nvmem; + struct nvmem_blob *nblob; + struct property *pp; + struct nvmem_config nv_cnf = {0}; + struct regmap_config rm_cnf = {0}; + + ret = nvmem_blob_validate_dt(np); + if (ret < 0) { + dev_dbg(dev, "Device tree validation failed\n"); + return ret; + } + + nblob = devm_kzalloc(dev, sizeof(*nblob), GFP_KERNEL); + if (!nblob) { + dev_dbg(dev, "Not enough memory to allocate a blob\n"); + return -ENOMEM; + } + + pp = of_find_property(np, "data", NULL); + BUG_ON(!pp); + + nblob->data = pp->value; + nblob->data_size = pp->length; + + rm_cnf.reg_bits = 32; + rm_cnf.val_bits = 8; + rm_cnf.reg_stride = 1; + rm_cnf.name = "nvmem-blob"; + rm_cnf.max_register = nblob->data_size - 1; + + map = devm_regmap_init(dev, + &nvmem_blob_regmap_bus, + nblob, + &rm_cnf); + if (IS_ERR(map)) { + dev_dbg(dev, "Failed to initilize regmap\n"); + return PTR_ERR(map); + } + + nv_cnf.name = "nvmem-blob"; + nv_cnf.read_only = true; + nv_cnf.dev = dev; + nv_cnf.owner = THIS_MODULE; + + nvmem = nvmem_register(&nv_cnf); + if (IS_ERR(nvmem)) { + dev_dbg(dev, "Filed to register nvmem device\n"); + return PTR_ERR(nvmem); + } + + platform_set_drvdata(pdev, nblob); + return 0; +} + +static int nvmem_blob_remove(struct platform_device *pdev) +{ + struct nvmem_device *nvmem = platform_get_drvdata(pdev); + + return nvmem_unregister(nvmem); +} + +static const struct of_device_id nvmem_blob_dt_ids[] = { + { .compatible = "nvmem-blob", }, + { }, +}; +MODULE_DEVICE_TABLE(of, nvmem_blob_dt_ids); + +static struct platform_driver nvmem_blob_driver = { + .probe = nvmem_blob_probe, + .remove = nvmem_blob_remove, + .driver = { + .name = "nvmem-blob", + .of_match_table = nvmem_blob_dt_ids, + }, +}; +module_platform_driver(nvmem_blob_driver); + +MODULE_AUTHOR("Andrey Smirnov <[email protected]>"); +MODULE_DESCRIPTION("FIXME"); +MODULE_LICENSE("GPL v2"); -- 2.5.0
