diff options
Diffstat (limited to 'drivers/base/soc.c')
| -rw-r--r-- | drivers/base/soc.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/drivers/base/soc.c b/drivers/base/soc.c new file mode 100644 index 000000000..d34609bb7 --- /dev/null +++ b/drivers/base/soc.c @@ -0,0 +1,267 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) ST-Ericsson SA 2011 + * + * Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson. + */ + +#include <linux/sysfs.h> +#include <linux/init.h> +#include <linux/stat.h> +#include <linux/slab.h> +#include <linux/idr.h> +#include <linux/spinlock.h> +#include <linux/sys_soc.h> +#include <linux/err.h> +#include <linux/glob.h> + +static DEFINE_IDA(soc_ida); + +/* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */ +static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr, + char *buf); + +struct soc_device { + struct device dev; + struct soc_device_attribute *attr; + int soc_dev_num; +}; + +static struct bus_type soc_bus_type = { + .name = "soc", +}; + +static DEVICE_ATTR(machine, 0444, soc_info_show, NULL); +static DEVICE_ATTR(family, 0444, soc_info_show, NULL); +static DEVICE_ATTR(serial_number, 0444, soc_info_show, NULL); +static DEVICE_ATTR(soc_id, 0444, soc_info_show, NULL); +static DEVICE_ATTR(revision, 0444, soc_info_show, NULL); + +struct device *soc_device_to_device(struct soc_device *soc_dev) +{ + return &soc_dev->dev; +} + +static umode_t soc_attribute_mode(struct kobject *kobj, + struct attribute *attr, + int index) +{ + struct device *dev = kobj_to_dev(kobj); + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine) + return attr->mode; + if ((attr == &dev_attr_family.attr) && soc_dev->attr->family) + return attr->mode; + if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision) + return attr->mode; + if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number) + return attr->mode; + if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id) + return attr->mode; + + /* Unknown or unfilled attribute */ + return 0; +} + +static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + const char *output; + + if (attr == &dev_attr_machine) + output = soc_dev->attr->machine; + else if (attr == &dev_attr_family) + output = soc_dev->attr->family; + else if (attr == &dev_attr_revision) + output = soc_dev->attr->revision; + else if (attr == &dev_attr_serial_number) + output = soc_dev->attr->serial_number; + else if (attr == &dev_attr_soc_id) + output = soc_dev->attr->soc_id; + else + return -EINVAL; + + return sysfs_emit(buf, "%s\n", output); +} + +static struct attribute *soc_attr[] = { + &dev_attr_machine.attr, + &dev_attr_family.attr, + &dev_attr_serial_number.attr, + &dev_attr_soc_id.attr, + &dev_attr_revision.attr, + NULL, +}; + +static const struct attribute_group soc_attr_group = { + .attrs = soc_attr, + .is_visible = soc_attribute_mode, +}; + +static void soc_release(struct device *dev) +{ + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + ida_simple_remove(&soc_ida, soc_dev->soc_dev_num); + kfree(soc_dev->dev.groups); + kfree(soc_dev); +} + +static struct soc_device_attribute *early_soc_dev_attr; + +struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr) +{ + struct soc_device *soc_dev; + const struct attribute_group **soc_attr_groups; + int ret; + + if (!soc_bus_type.p) { + if (early_soc_dev_attr) + return ERR_PTR(-EBUSY); + early_soc_dev_attr = soc_dev_attr; + return NULL; + } + + soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL); + if (!soc_dev) { + ret = -ENOMEM; + goto out1; + } + + soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL); + if (!soc_attr_groups) { + ret = -ENOMEM; + goto out2; + } + soc_attr_groups[0] = &soc_attr_group; + soc_attr_groups[1] = soc_dev_attr->custom_attr_group; + + /* Fetch a unique (reclaimable) SOC ID. */ + ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL); + if (ret < 0) + goto out3; + soc_dev->soc_dev_num = ret; + + soc_dev->attr = soc_dev_attr; + soc_dev->dev.bus = &soc_bus_type; + soc_dev->dev.groups = soc_attr_groups; + soc_dev->dev.release = soc_release; + + dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num); + + ret = device_register(&soc_dev->dev); + if (ret) { + put_device(&soc_dev->dev); + return ERR_PTR(ret); + } + + return soc_dev; + +out3: + kfree(soc_attr_groups); +out2: + kfree(soc_dev); +out1: + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(soc_device_register); + +/* Ensure soc_dev->attr is freed prior to calling soc_device_unregister. */ +void soc_device_unregister(struct soc_device *soc_dev) +{ + device_unregister(&soc_dev->dev); + early_soc_dev_attr = NULL; +} +EXPORT_SYMBOL_GPL(soc_device_unregister); + +static int __init soc_bus_register(void) +{ + int ret; + + ret = bus_register(&soc_bus_type); + if (ret) + return ret; + + if (early_soc_dev_attr) + return PTR_ERR(soc_device_register(early_soc_dev_attr)); + + return 0; +} +core_initcall(soc_bus_register); + +static int soc_device_match_attr(const struct soc_device_attribute *attr, + const struct soc_device_attribute *match) +{ + if (match->machine && + (!attr->machine || !glob_match(match->machine, attr->machine))) + return 0; + + if (match->family && + (!attr->family || !glob_match(match->family, attr->family))) + return 0; + + if (match->revision && + (!attr->revision || !glob_match(match->revision, attr->revision))) + return 0; + + if (match->soc_id && + (!attr->soc_id || !glob_match(match->soc_id, attr->soc_id))) + return 0; + + return 1; +} + +static int soc_device_match_one(struct device *dev, void *arg) +{ + struct soc_device *soc_dev = container_of(dev, struct soc_device, dev); + + return soc_device_match_attr(soc_dev->attr, arg); +} + +/* + * soc_device_match - identify the SoC in the machine + * @matches: zero-terminated array of possible matches + * + * returns the first matching entry of the argument array, or NULL + * if none of them match. + * + * This function is meant as a helper in place of of_match_node() + * in cases where either no device tree is available or the information + * in a device node is insufficient to identify a particular variant + * by its compatible strings or other properties. For new devices, + * the DT binding should always provide unique compatible strings + * that allow the use of of_match_node() instead. + * + * The calling function can use the .data entry of the + * soc_device_attribute to pass a structure or function pointer for + * each entry. + */ +const struct soc_device_attribute *soc_device_match( + const struct soc_device_attribute *matches) +{ + int ret = 0; + + if (!matches) + return NULL; + + while (!ret) { + if (!(matches->machine || matches->family || + matches->revision || matches->soc_id)) + break; + ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches, + soc_device_match_one); + if (ret < 0 && early_soc_dev_attr) + ret = soc_device_match_attr(early_soc_dev_attr, + matches); + if (ret < 0) + return NULL; + if (!ret) + matches++; + else + return matches; + } + return NULL; +} +EXPORT_SYMBOL_GPL(soc_device_match); |