[v2] Add support for PCIe SSD status LED management

Message ID	20210601203820.3647-1-stuart.w.hayes@gmail.com (mailing list archive)
State	Superseded
Delegated to:	Bjorn Helgaas
Headers	show Return-Path: <linux-pci-owner@kernel.org> From: Stuart Hayes <stuart.w.hayes@gmail.com> To: Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org Cc: Keith Busch <kbusch@kernel.org>, kw@linux.com, Stuart Hayes <stuart.w.hayes@gmail.com> Subject: [PATCH v2] Add support for PCIe SSD status LED management Date: Tue, 1 Jun 2021 16:38:20 -0400 Message-Id: <20210601203820.3647-1-stuart.w.hayes@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	[v2] Add support for PCIe SSD status LED management \| expand [v2] Add support for PCIe SSD status LED management

diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-pcie-ssd-leds b/Documentation/ABI/testing/sysfs-class-led-driver-pcie-ssd-leds new file mode 100644 index 000000000000..1f07733b6f35 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-led-driver-pcie-ssd-leds @@ -0,0 +1,18 @@ +What: /sys/class/leds/<led>/states +Date: April 2021 +Contact: linux-pci@vger.kernel.org +Description: + This attribute indicates the status states supported by a drive + or drive slot's LEDs, as defined in the "_DSM additions for PCIe + SSD Status LED Management" ECN to the PCI Firmware Specification + Revision 3.2, dated 12 February 2020, and in "Native PCIe + Enclosure Management", section 6.29 of the PCIe Base Spec 5.0. + + Only supported states will be shown, and the currently active + states are shown in brackets. The active state(s) can be written + by echoing a space or comma separated string of states to this + attribute. For example: + + # echo "ok locate" >/sys/class/leds/0000:88:00.0::drive_status/states + # cat /sys/class/leds/0000:88:00.0::drive_status/states + [ok] [locate] failed rebuild pfa hotspare ica ifa invalid disabled diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 0c473d75e625..f4acf1ad0fb5 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -190,6 +190,18 @@ config PCI_HYPERV The PCI device frontend driver allows the kernel to import arbitrary PCI devices from a PCI backend to support PCI driver domains. +config PCIE_SSD_LEDS + tristate "PCIe SSD status LED support" + depends on ACPI && NEW_LEDS + help + Driver for PCIe SSD status LED management as described in a PCI + Firmware Specification, Revision 3.2 ECN. + + When enabled, an LED interface will be created for each PCIe device + that has the ACPI method described in the referenced specification, + to allow the device status LEDs for that PCIe device (presumably a + solid state storage device or its slot) to be seen and controlled. + choice prompt "PCI Express hierarchy optimization setting" default PCIE_BUS_DEFAULT diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile index d62c4ac4ae1b..ea0a0f351ad2 100644 --- a/drivers/pci/Makefile +++ b/drivers/pci/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_PCI_PF_STUB) += pci-pf-stub.o obj-$(CONFIG_PCI_ECAM) += ecam.o obj-$(CONFIG_PCI_P2PDMA) += p2pdma.o obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o +obj-$(CONFIG_PCIE_SSD_LEDS) += pcie-ssd-leds.o # Endpoint library must be initialized before its users obj-$(CONFIG_PCI_ENDPOINT) += endpoint/ diff --git a/drivers/pci/pcie-ssd-leds.c b/drivers/pci/pcie-ssd-leds.c new file mode 100644 index 000000000000..4a78ff598e09 --- /dev/null +++ b/drivers/pci/pcie-ssd-leds.c @@ -0,0 +1,457 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Module to provide LED interface control for PCIe SSD status LED states, + * as defined in the "_DSM additions for PCIe SSD Status LED Management" ECN + * to the PCI Firmware Specification Revision 3.2, dated 12 February 2020. + * + * Copyright (c) 2021 Dell Inc. + * + * TODO: Add NPEM support + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/acpi.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/pci.h> +#include <uapi/linux/uleds.h> + +#define DRIVER_NAME "pcie-ssd-leds" +#define DRIVER_VERSION "v1.0" + +struct led_state { + char *name; + u32 mask; +}; + +static struct led_state led_states[] = { + { .name = "ok", .mask = BIT(2) }, + { .name = "locate", .mask = BIT(3) }, + { .name = "failed", .mask = BIT(4) }, + { .name = "rebuild", .mask = BIT(5) }, + { .name = "pfa", .mask = BIT(6) }, + { .name = "hotspare", .mask = BIT(7) }, + { .name = "ica", .mask = BIT(8) }, + { .name = "ifa", .mask = BIT(9) }, + { .name = "invalid", .mask = BIT(10) }, + { .name = "disabled", .mask = BIT(11) }, +}; + +struct drive_status_led_ops { + int (*get_supported_states)(struct device *dev, u32 *states); + int (*get_current_states)(struct device *dev, u32 *states); + int (*set_current_states)(struct device *dev, u32 states); +}; + +/* + * one drive_status_dev struct for each drive/slot device with status LEDs + */ +struct drive_status_dev { + struct list_head drive_list; + struct device *dev; + struct drive_status_led_ops *ops; + u32 supported_states; + struct led_classdev led_cdev; + enum led_brightness brightness; +}; + +struct mutex drive_list_lock; +struct list_head drive_list; + +/* + * code specific to _DSM method + */ +const guid_t pcie_ssdleds_dsm_guid = + GUID_INIT(0x5d524d9d, 0xfff9, 0x4d4b, + 0x8c, 0xb7, 0x74, 0x7e, 0xd5, 0x1e, 0x19, 0x4d); + +#define GET_SUPPORTED_STATES_DSM 0x01 +#define GET_STATE_DSM 0x02 +#define SET_STATE_DSM 0x03 + +struct ssdleds_dsm_output { + u16 status; + u8 function_specific_err; + u8 vendor_specific_err; + u32 state; +}; + +static void dsm_status_err_print(struct device *dev, + struct ssdleds_dsm_output *output) +{ + switch (output->status) { + case 0: + break; + case 1: + dev_dbg(dev, "_DSM not supported\n"); + break; + case 2: + dev_dbg(dev, "_DSM invalid input parameters\n"); + break; + case 3: + dev_dbg(dev, "_DSM communication error\n"); + break; + case 4: + dev_dbg(dev, "_DSM function-specific error 0x%x\n", + output->function_specific_err); + break; + case 5: + dev_dbg(dev, "_DSM vendor-specific error 0x%x\n", + output->vendor_specific_err); + break; + default: + dev_dbg(dev, "_DSM returned unknown status 0x%x\n", + output->status); + } +} + +static int dsm_set(struct device *dev, u32 value) +{ + acpi_handle handle; + union acpi_object *out_obj, arg3[2]; + struct ssdleds_dsm_output *dsm_output; + + handle = ACPI_HANDLE(dev); + if (!handle) + return -ENODEV; + + arg3[0].type = ACPI_TYPE_PACKAGE; + arg3[0].package.count = 1; + arg3[0].package.elements = &arg3[1]; + + arg3[1].type = ACPI_TYPE_BUFFER; + arg3[1].buffer.length = 4; + arg3[1].buffer.pointer = (u8 *)&value; + + out_obj = acpi_evaluate_dsm_typed(handle, &pcie_ssdleds_dsm_guid, + 1, SET_STATE_DSM, &arg3[0], ACPI_TYPE_BUFFER); + if (!out_obj) + return -EIO; + + if (out_obj->buffer.length < 8) { + ACPI_FREE(out_obj); + return -EIO; + } + + dsm_output = (struct ssdleds_dsm_output *)out_obj->buffer.pointer; + + if (dsm_output->status != 0) { + dsm_status_err_print(dev, dsm_output); + ACPI_FREE(out_obj); + return -EIO; + } + ACPI_FREE(out_obj); + return 0; +} + +static int dsm_get(struct device *dev, u64 dsm_func, u32 *output) +{ + acpi_handle handle; + union acpi_object *out_obj; + struct ssdleds_dsm_output *dsm_output; + + handle = ACPI_HANDLE(dev); + if (!handle) + return -ENODEV; + + out_obj = acpi_evaluate_dsm_typed(handle, &pcie_ssdleds_dsm_guid, 0x1, + dsm_func, NULL, ACPI_TYPE_BUFFER); + if (!out_obj) + return -EIO; + + if (out_obj->buffer.length < 8) { + ACPI_FREE(out_obj); + return -EIO; + } + + dsm_output = (struct ssdleds_dsm_output *)out_obj->buffer.pointer; + if (dsm_output->status != 0) { + dsm_status_err_print(dev, dsm_output); + ACPI_FREE(out_obj); + return -EIO; + } + + *output = dsm_output->state; + ACPI_FREE(out_obj); + return 0; +} + +static int get_supported_states_dsm(struct device *dev, u32 *states) +{ + return dsm_get(dev, GET_SUPPORTED_STATES_DSM, states); +} + +static int get_current_states_dsm(struct device *dev, u32 *states) +{ + return dsm_get(dev, GET_STATE_DSM, states); +} + +static int set_current_states_dsm(struct device *dev, u32 states) +{ + return dsm_set(dev, states); +} + +static bool pdev_has_dsm(struct pci_dev *pdev) +{ + acpi_handle handle; + + handle = ACPI_HANDLE(&pdev->dev); + if (!handle) + return false; + + return acpi_check_dsm(handle, &pcie_ssdleds_dsm_guid, 0x1, + 1 << GET_SUPPORTED_STATES_DSM || + 1 << GET_STATE_DSM || + 1 << SET_STATE_DSM); +} + +struct drive_status_led_ops dsm_drive_status_led_ops = { + .get_supported_states = get_supported_states_dsm, + .get_current_states = get_current_states_dsm, + .set_current_states = set_current_states_dsm, +}; + +/* + * code not specific to method (_DSM/NPEM) + */ +static ssize_t states_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct drive_status_dev *dsdev; + u32 val; + int err, i, res = 0; + + dsdev = container_of(led_cdev, struct drive_status_dev, led_cdev); + + err = dsdev->ops->get_current_states(dsdev->dev, &val); + if (err < 0) + return err; + + for (i = 0; i < ARRAY_SIZE(led_states); i++) { + if (led_states[i].mask & dsdev->supported_states & val) + res += sysfs_emit_at(buf, res, "[%s] ", + led_states[i].name); + else if (led_states[i].mask & dsdev->supported_states) + res += sysfs_emit_at(buf, res, "%s", + led_states[i].name); + } + res += sysfs_emit_at(buf, res, "\n"); + return res; +} + +static ssize_t states_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t size) +{ + struct led_classdev *led_cdev = dev_get_drvdata(dev); + struct drive_status_dev *dsdev; + u32 states = 0; + int err; + + /* + * parse input + * + * If multiple states are being set, they should be separated by + * spaces or commas. Input buffer may end with `\n`. + */ + while (*buf) { + size_t len; + int i; + + while (*buf == ' ' || *buf == ',' || *buf == '\n') + buf++; + len = strcspn(buf, " ,\n"); + if (!len) + break; + for (i = 0; i < ARRAY_SIZE(led_states); i++) { + if (!strncmp(buf, led_states[i].name, len)) { + states |= led_states[i].mask; + buf += len; + break; + } + } + if (i == ARRAY_SIZE(led_states)) + return -EINVAL; + } + + /* + * set states + */ + dsdev = container_of(led_cdev, struct drive_status_dev, led_cdev); + if (states & ~dsdev->supported_states) + return -EINVAL; + if (states) + dsdev->brightness = LED_ON; + + err = dsdev->ops->set_current_states(dsdev->dev, states); + if (err < 0) + return err; + + return size; +} +static DEVICE_ATTR_RW(states); + +static struct attribute *drive_status_attrs[] = { + &dev_attr_states.attr, + NULL +}; + +ATTRIBUTE_GROUPS(drive_status); + +static int drive_status_set_brightness(struct led_classdev *led_cdev, + enum led_brightness brightness) +{ + struct drive_status_dev *dsdev; + int err; + + dsdev = container_of(led_cdev, struct drive_status_dev, led_cdev); + dsdev->brightness = brightness; + + if (brightness == LED_OFF) { + err = dsdev->ops->set_current_states(dsdev->dev, 0); + if (err < 0) + return err; + } + return 0; +} + +static enum led_brightness drive_status_get_brightness(struct led_classdev *led_cdev) +{ + struct drive_status_dev *dsdev; + + dsdev = container_of(led_cdev, struct drive_status_dev, led_cdev); + return dsdev->brightness; +} + +static struct drive_status_dev *to_drive_status_dev(struct device *dev) +{ + struct drive_status_dev *dsdev; + + mutex_lock(&drive_list_lock); + list_for_each_entry(dsdev, &drive_list, drive_list) + if (dev == dsdev->dev) { + mutex_unlock(&drive_list_lock); + return dsdev; + } + mutex_unlock(&drive_list_lock); + return NULL; +} + +static void remove_drive_status_dev(struct drive_status_dev *dsdev) +{ + if (dsdev) { + mutex_lock(&drive_list_lock); + list_del(&dsdev->drive_list); + mutex_unlock(&drive_list_lock); + led_classdev_unregister(&dsdev->led_cdev); + kfree(dsdev); + } +} + +static void add_drive_status_dev(struct device *dev, + struct drive_status_led_ops *ops) +{ + u32 supported_states; + int ret; + struct drive_status_dev *dsdev; + char name[LED_MAX_NAME_SIZE]; + + if (to_drive_status_dev(dev)) + /* + * led has already been added for this dev + */ + return; + + if (ops->get_supported_states(dev, &supported_states) < 0) + return; + + dsdev = kzalloc(sizeof(*dsdev), GFP_KERNEL); + if (!dsdev) + return; + + dsdev->dev = dev; + dsdev->ops = ops; + dsdev->supported_states = supported_states; + dsdev->brightness = LED_ON; + snprintf(name, sizeof(name), "%s::%s", + dev_name(dev), "drive_status"); + + dsdev->led_cdev.name = name; + dsdev->led_cdev.max_brightness = LED_ON; + dsdev->led_cdev.brightness_set_blocking = drive_status_set_brightness; + dsdev->led_cdev.brightness_get = drive_status_get_brightness; + dsdev->led_cdev.groups = drive_status_groups; + ret = led_classdev_register(dev, &dsdev->led_cdev); + if (ret) { + pr_warn("Failed to register LED %s\n", dsdev->led_cdev.name); + remove_drive_status_dev(dsdev); + return; + } + + mutex_lock(&drive_list_lock); + list_add_tail(&dsdev->drive_list, &drive_list); + mutex_unlock(&drive_list_lock); +} + +/* + * code specific to PCIe devices + */ +static void probe_pdev(struct pci_dev *pdev) +{ + if (pdev_has_dsm(pdev)) + add_drive_status_dev(&pdev->dev, &dsm_drive_status_led_ops); +} + +static int pciessdleds_pci_bus_notifier_cb(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct pci_dev *pdev = to_pci_dev(data); + + if (action == BUS_NOTIFY_ADD_DEVICE) + probe_pdev(pdev); + else if (action == BUS_NOTIFY_DEL_DEVICE) + remove_drive_status_dev(to_drive_status_dev(&pdev->dev)); + return NOTIFY_DONE; +} + +static struct notifier_block pciessdleds_pci_bus_nb = { + .notifier_call = pciessdleds_pci_bus_notifier_cb, + .priority = INT_MIN, +}; + +static void initial_scan_for_leds(void) +{ + struct pci_dev *pdev = NULL; + + for_each_pci_dev(pdev) + probe_pdev(pdev); +} + +static int __init pciessdleds_init(void) +{ + mutex_init(&drive_list_lock); + INIT_LIST_HEAD(&drive_list); + + bus_register_notifier(&pci_bus_type, &pciessdleds_pci_bus_nb); + initial_scan_for_leds(); + return 0; +} + +static void __exit pciessdleds_exit(void) +{ + struct drive_status_dev *dsdev, *temp; + + bus_unregister_notifier(&pci_bus_type, &pciessdleds_pci_bus_nb); + list_for_each_entry_safe(dsdev, temp, &drive_list, drive_list) + remove_drive_status_dev(dsdev); +} + +module_init(pciessdleds_init); +module_exit(pciessdleds_exit); + +MODULE_AUTHOR("Stuart Hayes <stuart.w.hayes@gmail.com>"); +MODULE_DESCRIPTION("Support for PCIe SSD Status LED Management _DSM"); +MODULE_LICENSE("GPL");

[v2] Add support for PCIe SSD status LED management

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