On Sun, 2020-03-22 at 10:43 +0100, Enric Balletbo i Serra wrote: > This driver attaches to the ChromeOS ACPI device and then exports the > values > reported by the ACPI in a sysfs directory. The ACPI values are > presented in > the string form (numbers as decimal values) or binary blobs, and can > be > accessed as the contents of the appropriate read only files in the > sysfs > directory tree originating in /sys/devices/platform/chromeos_acpi. > > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx> > --- > [...] > /sys/devices/platform/chromeos_acpi/BINF.2 : 1 Just wondering why don't you create additional attributes under ACPI device itself, like in your case: /sys/bus/acpi/devices/GGL0001/* Additional attributes are added for ACPI device objects at such location in other cases also for some PNP* and INT3* objects. This will make your driver simple with one attr group. Thanks, Srinivas > /sys/devices/platform/chromeos_acpi/FMAP : -2031616 > /sys/devices/platform/chromeos_acpi/HWID : SAMUS E25-G7R-W35 > /sys/devices/platform/chromeos_acpi/BINF.0 : 0 > /sys/devices/platform/chromeos_acpi/GPIO.0/GPIO.2 : -1 > /sys/devices/platform/chromeos_acpi/GPIO.0/GPIO.0 : 1 > /sys/devices/platform/chromeos_acpi/GPIO.0/GPIO.3 : INT3437:00 > /sys/devices/platform/chromeos_acpi/GPIO.0/GPIO.1 : 0 > /sys/devices/platform/chromeos_acpi/FRID : Google_Samus.6300.102.0 > /sys/devices/platform/chromeos_acpi/VBNV.0 : 38 > /sys/devices/platform/chromeos_acpi/BINF.3 : 2 > /sys/devices/platform/chromeos_acpi/BINF.1 : 1 > /sys/devices/platform/chromeos_acpi/GPIO.1/GPIO.2 : 16 > /sys/devices/platform/chromeos_acpi/GPIO.1/GPIO.0 : 3 > /sys/devices/platform/chromeos_acpi/GPIO.1/GPIO.3 : INT3437:00 > /sys/devices/platform/chromeos_acpi/GPIO.1/GPIO.1 : 1 > /sys/devices/platform/chromeos_acpi/CHSW : 0 > /sys/devices/platform/chromeos_acpi/FWID : Google_Samus.6300.330.0 > /sys/devices/platform/chromeos_acpi/VBNV.1 : 16 > /sys/devices/platform/chromeos_acpi/BINF.4 : 0 > > And for binary packages: > > cat /sys/devices/platform/chromeos_acpi/MECK | hexdump > 0000000 02fb 8e72 a025 0a73 0f13 095e 9e07 41e6 > 0000010 f9e6 bb4e 76cc bef9 cca7 70e2 8f6d 863d > 0000020 > > cat /sys/devices/platform/chromeos_acpi/VDAT | hexdump > 0000000 6256 4453 0002 0000 0448 0000 0000 0000 > 0000010 0c00 0000 0000 0000 0850 0000 0000 0000 > 0000020 7c54 0003 0000 0000 0420 0000 0000 0000 > 0000030 0408 0000 0000 0000 0007 0000 0000 0000 > 0000040 0003 0000 0000 0000 0448 0000 0000 0000 > 0000050 0408 0000 0000 0000 9335 1f80 0000 0000 > 0000060 69a8 21f3 0000 0000 1d02 21f9 0000 0000 > 0000070 ba55 371b 0000 0000 0000 0000 0000 0000 > 0000080 bcae 001d 0000 0000 0003 0001 0001 0003 > 0000090 000c 0000 0003 0001 0003 0001 0001 0000 > 00000a0 0001 0000 0000 0000 cc00 01da 0000 0000 > 00000b0 0200 0000 0204 0000 0001 0000 0000 0000 > 00000c0 0800 0000 0000 0000 0000 0001 0000 0000 > 00000d0 0001 0001 1301 0000 0000 0000 0000 0000 > 00000e0 0000 0000 0000 0000 0000 0000 0000 0000 > * > > Thanks, > Enric > > [1] https://lkml.org/lkml/2017/7/31/378 > > Changes in v2: > - Note that this version is a total rework, with those major changes: > - Use lists to track dinamically allocated attributes and groups. > - Use sysfs binary attributes to store the ACPI contents. > - Remove all the functionalities except the one that creates the > sysfs files. > > drivers/platform/x86/Kconfig | 12 + > drivers/platform/x86/Makefile | 1 + > drivers/platform/x86/chromeos_acpi.c | 489 > +++++++++++++++++++++++++++ > 3 files changed, 502 insertions(+) > create mode 100644 drivers/platform/x86/chromeos_acpi.c > > diff --git a/drivers/platform/x86/Kconfig > b/drivers/platform/x86/Kconfig > index 587403c44598..917a1c1a0758 100644 > --- a/drivers/platform/x86/Kconfig > +++ b/drivers/platform/x86/Kconfig > @@ -72,6 +72,18 @@ config ACERHDF > If you have an Acer Aspire One netbook, say Y or M > here. > > +config ACPI_CHROMEOS > + tristate "ChromeOS specific ACPI extensions" > + depends on ACPI > + depends on CHROME_PLATFORMS > + help > + This driver provides the firmware interface for the services > + exported through the ChromeOS interfaces when using ChromeOS > + ACPI firmware. > + > + If you have an ACPI-compatible Chromebook, say Y or M > + here. > + > config ALIENWARE_WMI > tristate "Alienware Special feature control" > depends on ACPI > diff --git a/drivers/platform/x86/Makefile > b/drivers/platform/x86/Makefile > index 3747b1f07cf1..222e2e88ccb8 100644 > --- a/drivers/platform/x86/Makefile > +++ b/drivers/platform/x86/Makefile > @@ -83,6 +83,7 @@ obj-$(CONFIG_SAMSUNG_Q10) += samsung-q10.o > obj-$(CONFIG_APPLE_GMUX) += apple-gmux.o > obj-$(CONFIG_INTEL_RST) += intel-rst.o > obj-$(CONFIG_INTEL_SMARTCONNECT) += intel-smartconnect.o > +obj-$(CONFIG_ACPI_CHROMEOS) += chromeos_acpi.o > > obj-$(CONFIG_ALIENWARE_WMI) += alienware-wmi.o > obj-$(CONFIG_INTEL_PMC_IPC) += intel_pmc_ipc.o > diff --git a/drivers/platform/x86/chromeos_acpi.c > b/drivers/platform/x86/chromeos_acpi.c > new file mode 100644 > index 000000000000..4d9addee2473 > --- /dev/null > +++ b/drivers/platform/x86/chromeos_acpi.c > @@ -0,0 +1,489 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * ChromeOS specific ACPI extensions > + * > + * Copyright 2011 Google, Inc. > + * Copyright 2020 Google LLC > + * > + * This file is a rework and part of the code is ported from > + * drivers/platform/x86/chromeos_acpi.c of the chromeos-3.18 kernel > and > + * was originally written by Vadim Bendebury <vbendeb@xxxxxxxxxxxx>. > + * > + * This driver attaches to the ChromeOS ACPI device and then exports > the > + * values reported by the ACPI in a sysfs directory. All values are > + * presented in the string form (numbers as decimal values) and can > be > + * accessed as the contents of the appropriate read only files in > the > + * sysfs directory tree originating in > /sys/devices/platform/chromeos_acpi. > + */ > + > +#include <linux/acpi.h> > +#include <linux/kernel.h> > +#include <linux/list.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > + > +/* > + * ACPI method name for MLST; the response for this method is a > package of > + * strings listing the methods which should be reflected in sysfs. > + */ > +#define MLST "MLST" > + > +/* > + * The default list of methods the ChromeOS ACPI device is supposed > to export, > + * if the MLST method is not present or is poorly formed. The MLST > method > + * itself is included, to aid in debugging. > + */ > +static char *chromeos_acpi_default_methods[] = { > + "CHSW", "HWID", "BINF", "GPIO", "CHNV", "FWID", "FRID", MLST > +}; > + > +/* > + * Representation of a single sysfs attribute. In addition to the > standard > + * bin_attribute structure has a list of these structures (to keep > track for > + * de-allocation when removing the driver) and a pointer to the > actual > + * attribute name and value, reported when accessing the appropriate > sysfs > + * file. > + */ > +struct chromeos_acpi_attribute { > + struct bin_attribute bin_attr; > + struct list_head list; > + char *name; > + char *data; > +}; > + > +/* > + * Representation of a sysfs attribute group (a sub directory in the > device's > + * sysfs directory). In addition to the standard structure has lists > to allow > + * to keep track of the allocated structures. > + */ > +struct chromeos_acpi_attribute_group { > + struct list_head attribs; > + struct list_head list; > + struct kobject *kobj; /* chromeos_acpi/name directory */ > + char *name; > +}; > + > +/* > + * This is the main structure, we use it to store data and adds > links pointing > + * at lists of allocated attributes and attribute groups. > + */ > +struct chromeos_acpi_dev { > + struct platform_device *pdev; > + > + struct chromeos_acpi_attribute_group root; > + struct list_head groups; > +}; > + > +static struct chromeos_acpi_dev chromeos_acpi; > + > +static ssize_t chromeos_acpi_read_bin_attribute(struct file *filp, > + struct kobject *kobj, > + struct bin_attribute > *bin_attr, > + char *buffer, loff_t > pos, > + size_t count) > +{ > + struct chromeos_acpi_attribute *info = bin_attr->private; > + > + return memory_read_from_buffer(buffer, count, &pos, info->data, > + info->bin_attr.size); > +} > + > +static char *chromeos_acpi_alloc_name(char *name, int count, int > index) > +{ > + char *str; > + > + if (count == 1) > + str = kstrdup(name, GFP_KERNEL); > + else > + str = kasprintf(GFP_KERNEL, "%s.%d", name, index); > + > + return str; > +} > + > +static int > +chromeos_acpi_add_attr(struct chromeos_acpi_attribute_group *aag, > + union acpi_object *element, char *name, > + int count, int index) > +{ > + struct chromeos_acpi_attribute *info; > + char buffer[24]; /* enough to store a u64 and "\n\0" */ > + int length; > + int ret; > + > + info = kzalloc(sizeof(*info), GFP_KERNEL); > + if (!info) > + return -ENOMEM; > + > + info->name = chromeos_acpi_alloc_name(name, count, index); > + if (!info->name) { > + ret = -ENOMEM; > + goto free_attribute; > + } > + > + sysfs_bin_attr_init(&info->bin_attr); > + info->bin_attr.attr.name = info->name; > + info->bin_attr.attr.mode = 0444; > + > + switch (element->type) { > + case ACPI_TYPE_BUFFER: > + length = element->buffer.length; > + info->data = kmemdup(element->buffer.pointer, > + length, GFP_KERNEL); > + break; > + case ACPI_TYPE_INTEGER: > + length = snprintf(buffer, sizeof(buffer), "%d", > + (int)element->integer.value); > + info->data = kmemdup(buffer, length, GFP_KERNEL); > + break; > + case ACPI_TYPE_STRING: > + length = element->string.length + 1; > + info->data = kstrdup(element->string.pointer, > GFP_KERNEL); > + break; > + default: > + ret = -EINVAL; > + goto free_attr_name; > + } > + > + if (!info->data) { > + ret = -ENOMEM; > + goto free_attr_name; > + } > + > + info->bin_attr.size = length; > + info->bin_attr.read = chromeos_acpi_read_bin_attribute; > + info->bin_attr.private = info; > + > + INIT_LIST_HEAD(&info->list); > + > + ret = sysfs_create_bin_file(aag->kobj, &info->bin_attr); > + if (ret) > + goto free_attr_data; > + > + list_add(&info->list, &aag->attribs); > + > + return 0; > + > +free_attr_data: > + kfree(info->data); > +free_attr_name: > + kfree(info->name); > +free_attribute: > + kfree(info); > + return ret; > +} > + > +static void > +chromeos_acpi_remove_attribs(struct chromeos_acpi_attribute_group > *aag) > +{ > + struct chromeos_acpi_attribute *attr, *tmp_attr; > + > + list_for_each_entry_safe(attr, tmp_attr, &aag->attribs, list) { > + sysfs_remove_bin_file(aag->kobj, &attr->bin_attr); > + kfree(attr->name); > + kfree(attr->data); > + kfree(attr); > + } > +} > + > +/** > + * chromeos_acpi_add_group() - Create a sysfs group including > attributes > + * representing a nested ACPI package. > + * > + * @obj: Package contents as returned by ACPI. > + * @name: Name of the group. > + * @num_attrs: Number of attributes of this package. > + * @index: Index number of this particular group. > + * > + * The created group is called @name in case there is a single > instance, or > + * @name.@index otherwise. > + * > + * All group and attribute storage allocations are included in the > lists for > + * tracking of allocated memory. > + * > + * Return: 0 on success, negative errno on failure. > + */ > +static int chromeos_acpi_add_group(union acpi_object *obj, char > *name, > + int num_attrs, int index) > +{ > + struct device *dev = &chromeos_acpi.pdev->dev; > + struct chromeos_acpi_attribute_group *aag; > + union acpi_object *element; > + int i, count, ret; > + > + aag = kzalloc(sizeof(*aag), GFP_KERNEL); > + if (!aag) > + return -ENOMEM; > + > + aag->name = chromeos_acpi_alloc_name(name, num_attrs, index); > + if (!aag->name) { > + ret = -ENOMEM; > + goto free_group; > + } > + > + aag->kobj = kobject_create_and_add(aag->name, &dev->kobj); > + if (!aag->kobj) { > + ret = -EINVAL; > + goto free_group_name; > + } > + > + INIT_LIST_HEAD(&aag->attribs); > + INIT_LIST_HEAD(&aag->list); > + > + count = obj->package.count; > + element = obj->package.elements; > + for (i = 0; i < count; i++, element++) { > + ret = chromeos_acpi_add_attr(aag, element, name, count, > i); > + if (ret) > + goto free_group_attr; > + } > + > + list_add(&aag->list, &chromeos_acpi.groups); > + > + return 0; > + > +free_group_attr: > + chromeos_acpi_remove_attribs(aag); > + kobject_put(aag->kobj); > +free_group_name: > + kfree(aag->name); > +free_group: > + kfree(aag); > + return ret; > +} > + > +static void chromeos_acpi_remove_groups(void) > +{ > + struct chromeos_acpi_attribute_group *aag, *tmp_aag; > + > + list_for_each_entry_safe(aag, tmp_aag, &chromeos_acpi.groups, > list) { > + chromeos_acpi_remove_attribs(aag); > + kfree(aag->name); > + kobject_put(aag->kobj); > + kfree(aag); > + } > +} > + > +/** > + * chromeos_acpi_handle_package() - Create sysfs group including > attributes > + * representing an ACPI package. > + * > + * @obj: Package contents as returned by ACPI. > + * @name: Name of the group. > + * > + * Scalar objects included in the package get sysfs attributes > created for > + * them. Nested packages are passed to a function creating a sysfs > group per > + * package. > + * > + * Return: 0 on success, negative errno on failure. > + */ > +static int chromeos_acpi_handle_package(union acpi_object *obj, char > *name) > +{ > + struct device *dev = &chromeos_acpi.pdev->dev; > + int count = obj->package.count; > + union acpi_object *element; > + int i, ret = 0; > + > + element = obj->package.elements; > + for (i = 0; i < count; i++, element++) { > + if (element->type == ACPI_TYPE_BUFFER || > + element->type == ACPI_TYPE_STRING || > + element->type == ACPI_TYPE_INTEGER) > + /* Create a single attribute in the root > directory */ > + ret = > chromeos_acpi_add_attr(&chromeos_acpi.root, > + element, name, > + count, i); > + else if (element->type == ACPI_TYPE_PACKAGE) > + /* Create a group of attributes */ > + ret = chromeos_acpi_add_group(element, name, > + count, i); > + else > + ret = -EINVAL; > + if (ret) > + dev_err(dev, > + "failed to create group attributes > (%d)\n", > + ret); > + } > + > + return ret; > +} > + > +/** > + * chromeos_acpi_add_method() - Evaluate an ACPI method and create > sysfs > + * attributes. > + * > + * @adev: ACPI device > + * @name: Name of the method to evaluate > + * > + * Return: 0 on success, non-zero on failure > + */ > +static int chromeos_acpi_add_method(struct acpi_device *adev, char > *name) > +{ > + struct device *dev = &chromeos_acpi.pdev->dev; > + struct acpi_buffer output; > + union acpi_object *obj; > + acpi_status status; > + int ret = 0; > + > + output.length = ACPI_ALLOCATE_BUFFER; > + > + status = acpi_evaluate_object(adev->handle, name, NULL, > &output); > + if (ACPI_FAILURE(status)) { > + dev_err(dev, "failed to retrieve %s (%d)\n", name, > status); > + return status; > + } > + > + obj = output.pointer; > + if (obj->type == ACPI_TYPE_PACKAGE) > + ret = chromeos_acpi_handle_package(obj, name); > + > + kfree(output.pointer); > + > + return ret; > +} > + > +/** > + * chromeos_acpi_process_mlst() - Evaluate the MLST method and add > methods > + * listed in the response. > + * > + * @adev: ACPI device > + * > + * Returns: 0 if successful, non-zero if error. > + */ > +static int chromeos_acpi_process_mlst(struct acpi_device *adev) > +{ > + char name[ACPI_NAMESEG_SIZE + 1]; > + union acpi_object *element, *obj; > + struct acpi_buffer output; > + acpi_status status; > + int ret = 0; > + int size; > + int i; > + > + output.length = ACPI_ALLOCATE_BUFFER; > + status = acpi_evaluate_object(adev->handle, MLST, NULL, > + &output); > + if (ACPI_FAILURE(status)) > + return status; > + > + obj = output.pointer; > + if (obj->type != ACPI_TYPE_PACKAGE) { > + ret = -EINVAL; > + goto free_acpi_buffer; > + } > + > + element = obj->package.elements; > + for (i = 0; i < obj->package.count; i++, element++) { > + if (element->type == ACPI_TYPE_STRING) { > + size = min(element->string.length + 1, > + (u32)ACPI_NAMESEG_SIZE + 1); > + strlcpy(name, element->string.pointer, size); > + ret = chromeos_acpi_add_method(adev, name); > + if (ret) { > + chromeos_acpi_remove_groups(); > + break; > + } > + } > + } > + > +free_acpi_buffer: > + kfree(output.pointer); > + > + return ret; > +} > + > +static int chromeos_acpi_device_add(struct acpi_device *adev) > +{ > + struct chromeos_acpi_attribute_group *aag = > &chromeos_acpi.root; > + struct device *dev = &chromeos_acpi.pdev->dev; > + int i, ret; > + > + INIT_LIST_HEAD(&aag->attribs); > + INIT_LIST_HEAD(&aag->list); > + > + aag->kobj = &dev->kobj; > + > + /* > + * Attempt to add methods by querying the device's MLST method > + * for the list of methods. > + */ > + if (!chromeos_acpi_process_mlst(adev)) > + return 0; > + > + dev_info(dev, "falling back to default list of methods\n"); > + > + for (i = 0; i < ARRAY_SIZE(chromeos_acpi_default_methods); i++) > { > + ret = chromeos_acpi_add_method(adev, > + chromeos_acpi_default_meth > ods[i]); > + if (ret) { > + dev_err(dev, "failed to add default methods > (%d)\n", > + ret); > + return ret; > + } > + } > + > + return 0; > +} > + > +static int chromeos_acpi_device_remove(struct acpi_device *adev) > +{ > + /* Remove dinamically allocated sysfs groups and attributes */ > + chromeos_acpi_remove_groups(); > + /* Remove attributes from the root group */ > + chromeos_acpi_remove_attribs(&chromeos_acpi.root); > + > + return 0; > +} > + > +static const struct acpi_device_id chromeos_device_ids[] = { > + { "GGL0001", 0 }, > + { } > +}; > +MODULE_DEVICE_TABLE(acpi, chromeos_device_ids); > + > +static struct acpi_driver chromeos_acpi_driver = { > + .name = "ChromeOS ACPI driver", > + .class = "chromeos-acpi", > + .ids = chromeos_device_ids, > + .ops = { > + .add = chromeos_acpi_device_add, > + .remove = chromeos_acpi_device_remove, > + }, > + .owner = THIS_MODULE, > +}; > + > +static int __init chromeos_acpi_init(void) > +{ > + int ret; > + > + chromeos_acpi.pdev = > platform_device_register_simple("chromeos_acpi", > + PLATFORM_DEVID_NONE, > NULL, 0); > + if (IS_ERR(chromeos_acpi.pdev)) { > + pr_err("unable to register chromeos_acpi platform > device\n"); > + return PTR_ERR(chromeos_acpi.pdev); > + } > + > + INIT_LIST_HEAD(&chromeos_acpi.groups); > + > + ret = acpi_bus_register_driver(&chromeos_acpi_driver); > + if (ret < 0) { > + pr_err("failed to register chromeos_acpi driver > (%d)\n", ret); > + platform_device_unregister(chromeos_acpi.pdev); > + chromeos_acpi.pdev = NULL; > + return ret; > + } > + > + return 0; > +} > + > +static void __exit chromeos_acpi_exit(void) > +{ > + acpi_bus_unregister_driver(&chromeos_acpi_driver); > + platform_device_unregister(chromeos_acpi.pdev); > +} > + > +module_init(chromeos_acpi_init); > +module_exit(chromeos_acpi_exit); > + > +MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx> > "); > +MODULE_LICENSE("GPL"); > +MODULE_DESCRIPTION("ChromeOS specific ACPI extensions");
