On 05/10/2023 16:59, Miquel Raynal wrote:
, int index); + +static ssize_t nvmem_cell_attr_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *attr, char *buf, + loff_t pos, size_t count) +{ + struct nvmem_cell_entry *entry; + struct nvmem_cell *cell = NULL; + size_t cell_sz, read_len; + void *content; + + entry = attr->private; + cell = nvmem_create_cell(entry, entry->name, 0); + if (IS_ERR(cell)) + return PTR_ERR(cell); + + if (!cell) + return -EINVAL; + + content = nvmem_cell_read(cell, &cell_sz); + if (IS_ERR(content)) { + read_len = PTR_ERR(content); + goto destroy_cell; + } + + read_len = min_t(unsigned int, cell_sz - pos, count); + memcpy(buf, content + pos, read_len); + kfree(content); + +destroy_cell: + kfree_const(cell->id); + kfree(cell); + + return read_len; +} + /* default read/write permissions */ static struct bin_attribute bin_attr_rw_nvmem = { .attr = { @@ -320,11 +357,21 @@ static const struct attribute_group nvmem_bin_group = { .is_bin_visible = nvmem_bin_attr_is_visible, };+/* Cell attributes will be dynamically allocated */+static struct attribute_group nvmem_cells_group = { + .name = "cells", +}; + static const struct attribute_group *nvmem_dev_groups[] = { &nvmem_bin_group, NULL, };+static const struct attribute_group *nvmem_cells_groups[] = {+ &nvmem_cells_group, + NULL, +}; + static struct bin_attribute bin_attr_nvmem_eeprom_compat = { .attr = { .name = "eeprom", @@ -380,6 +427,68 @@ static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); }+static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)+{ + struct bin_attribute **cells_attrs, *attrs; + struct nvmem_cell_entry *entry; + unsigned int ncells = 0, i = 0; + int ret = 0; + + mutex_lock(&nvmem_mutex); + + if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated) { + nvmem_cells_group.bin_attrs = NULL; + goto unlock_mutex; + } + + /* Allocate an array of attributes with a sentinel */ + ncells = list_count_nodes(&nvmem->cells); + cells_attrs = devm_kcalloc(&nvmem->dev, ncells + 1, + sizeof(struct bin_attribute *), GFP_KERNEL); + if (!cells_attrs) { + ret = -ENOMEM; + goto unlock_mutex; + } + + attrs = devm_kcalloc(&nvmem->dev, ncells, sizeof(struct bin_attribute), GFP_KERNEL); + if (!attrs) { + ret = -ENOMEM; + goto unlock_mutex; + } + + /* Initialize each attribute to take the name and size of the cell */ + list_for_each_entry(entry, &nvmem->cells, node) { + sysfs_bin_attr_init(&attrs[i]); + attrs[i].attr.name = devm_kasprintf(&nvmem->dev, GFP_KERNEL, + "%s@%x", entry->name, + entry->offset); + attrs[i].attr.mode = 0444; + attrs[i].size = entry->bytes; + attrs[i].read = &nvmem_cell_attr_read; + attrs[i].private = entry; + if (!attrs[i].attr.name) { + ret = -ENOMEM; + goto unlock_mutex; + } + + cells_attrs[i] = &attrs[i]; + i++; + } + + nvmem_cells_group.bin_attrs = cells_attrs; + + ret = devm_device_add_groups(&nvmem->dev, nvmem_cells_groups); + if (ret) + goto unlock_mutex;
This is going to create groups after the nvmem device is added, isn't this going to be problem with user space notifications?
--srini
+ + nvmem->sysfs_cells_populated = true; + +unlock_mutex: + mutex_unlock(&nvmem_mutex); + + return ret;
