diff options
Diffstat (limited to 'drivers/pci/npem.c')
| -rw-r--r-- | drivers/pci/npem.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/drivers/pci/npem.c b/drivers/pci/npem.c new file mode 100644 index 000000000000..5fe33d145108 --- /dev/null +++ b/drivers/pci/npem.c @@ -0,0 +1,423 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCIe Enclosure management driver created for LED interfaces based on + * indications. It says *what indications* blink but does not specify *how* + * they blink - it is hardware defined. + * + * The driver name refers to Native PCIe Enclosure Management. It is + * first indication oriented standard with specification. + * + * Native PCIe Enclosure Management (NPEM) + * PCIe Base Specification r6.1 sec 6.28, 7.9.19 + * + * Copyright (c) 2023-2024 Intel Corporation + * Mariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com> + */ + +#include <linux/acpi.h> +#include <linux/bitops.h> +#include <linux/errno.h> +#include <linux/iopoll.h> +#include <linux/leds.h> +#include <linux/mutex.h> +#include <linux/pci.h> +#include <linux/pci_regs.h> +#include <linux/types.h> +#include <linux/uleds.h> + +#include "pci.h" + +struct indication { + u32 bit; + const char *name; +}; + +static const struct indication npem_indications[] = { + {PCI_NPEM_IND_OK, "enclosure:ok"}, + {PCI_NPEM_IND_LOCATE, "enclosure:locate"}, + {PCI_NPEM_IND_FAIL, "enclosure:fail"}, + {PCI_NPEM_IND_REBUILD, "enclosure:rebuild"}, + {PCI_NPEM_IND_PFA, "enclosure:pfa"}, + {PCI_NPEM_IND_HOTSPARE, "enclosure:hotspare"}, + {PCI_NPEM_IND_ICA, "enclosure:ica"}, + {PCI_NPEM_IND_IFA, "enclosure:ifa"}, + {PCI_NPEM_IND_IDT, "enclosure:idt"}, + {PCI_NPEM_IND_DISABLED, "enclosure:disabled"}, + {PCI_NPEM_IND_SPEC_0, "enclosure:specific_0"}, + {PCI_NPEM_IND_SPEC_1, "enclosure:specific_1"}, + {PCI_NPEM_IND_SPEC_2, "enclosure:specific_2"}, + {PCI_NPEM_IND_SPEC_3, "enclosure:specific_3"}, + {PCI_NPEM_IND_SPEC_4, "enclosure:specific_4"}, + {PCI_NPEM_IND_SPEC_5, "enclosure:specific_5"}, + {PCI_NPEM_IND_SPEC_6, "enclosure:specific_6"}, + {PCI_NPEM_IND_SPEC_7, "enclosure:specific_7"}, + {0, NULL} +}; + +#define for_each_indication(ind, inds) \ + for (ind = inds; ind->bit; ind++) + +/* + * The driver has internal list of supported indications. Ideally, the driver + * should not touch bits that are not defined and for which LED devices are + * not exposed but in reality, it needs to turn them off. + * + * Otherwise, there will be no possibility to turn off indications turned on by + * other utilities or turned on by default and it leads to bad user experience. + * + * Additionally, it excludes NPEM commands like RESET or ENABLE. + */ +static u32 reg_to_indications(u32 caps, const struct indication *inds) +{ + const struct indication *ind; + u32 supported_indications = 0; + + for_each_indication(ind, inds) + supported_indications |= ind->bit; + + return caps & supported_indications; +} + +/** + * struct npem_led - LED details + * @indication: indication details + * @npem: NPEM device + * @name: LED name + * @led: LED device + */ +struct npem_led { + const struct indication *indication; + struct npem *npem; + char name[LED_MAX_NAME_SIZE]; + struct led_classdev led; +}; + +/** + * struct npem_ops - backend specific callbacks + * @get_active_indications: get active indications + * npem: NPEM device + * inds: response buffer + * @set_active_indications: set new indications + * npem: npem device + * inds: bit mask to set + * @inds: supported indications array, set of indications is backend specific + * @name: backend name + */ +struct npem_ops { + int (*get_active_indications)(struct npem *npem, u32 *inds); + int (*set_active_indications)(struct npem *npem, u32 inds); + const struct indication *inds; + const char *name; +}; + +/** + * struct npem - NPEM device properties + * @dev: PCI device this driver is attached to + * @ops: backend specific callbacks + * @lock: serializes concurrent access to NPEM device by multiple LED devices + * @pos: cached offset of NPEM Capability Register in Configuration Space; + * only used if NPEM registers are accessed directly and not through _DSM + * @supported_indications: cached bit mask of supported indications; + * non-indication and reserved bits in the NPEM Capability Register are + * cleared in this bit mask + * @active_indications: cached bit mask of active indications; + * non-indication and reserved bits in the NPEM Control Register are + * cleared in this bit mask + * @led_cnt: size of @leds array + * @leds: array containing LED class devices of all supported LEDs + */ +struct npem { + struct pci_dev *dev; + const struct npem_ops *ops; + struct mutex lock; + u16 pos; + u32 supported_indications; + u32 active_indications; + int led_cnt; + struct npem_led leds[]; +}; + +static int npem_read_reg(struct npem *npem, u16 reg, u32 *val) +{ + int ret = pci_read_config_dword(npem->dev, npem->pos + reg, val); + + return pcibios_err_to_errno(ret); +} + +static int npem_write_ctrl(struct npem *npem, u32 reg) +{ + int pos = npem->pos + PCI_NPEM_CTRL; + int ret = pci_write_config_dword(npem->dev, pos, reg); + + return pcibios_err_to_errno(ret); +} + +static int npem_get_active_indications(struct npem *npem, u32 *inds) +{ + u32 ctrl; + int ret; + + ret = npem_read_reg(npem, PCI_NPEM_CTRL, &ctrl); + if (ret) + return ret; + + /* If PCI_NPEM_CTRL_ENABLE is not set then no indication should blink */ + if (!(ctrl & PCI_NPEM_CTRL_ENABLE)) { + *inds = 0; + return 0; + } + + *inds = ctrl & npem->supported_indications; + + return 0; +} + +static int npem_set_active_indications(struct npem *npem, u32 inds) +{ + int ctrl, ret, ret_val; + u32 cc_status; + + lockdep_assert_held(&npem->lock); + + /* This bit is always required */ + ctrl = inds | PCI_NPEM_CTRL_ENABLE; + + ret = npem_write_ctrl(npem, ctrl); + if (ret) + return ret; + + /* + * For the case where a NPEM command has not completed immediately, + * it is recommended that software not continuously "spin" on polling + * the status register, but rather poll under interrupt at a reduced + * rate; for example at 10 ms intervals. + * + * PCIe r6.1 sec 6.28 "Implementation Note: Software Polling of NPEM + * Command Completed" + */ + ret = read_poll_timeout(npem_read_reg, ret_val, + ret_val || (cc_status & PCI_NPEM_STATUS_CC), + 10 * USEC_PER_MSEC, USEC_PER_SEC, false, npem, + PCI_NPEM_STATUS, &cc_status); + if (ret) + return ret; + if (ret_val) + return ret_val; + + /* + * All writes to control register, including writes that do not change + * the register value, are NPEM commands and should eventually result + * in a command completion indication in the NPEM Status Register. + * + * PCIe Base Specification r6.1 sec 7.9.19.3 + * + * Register may not be updated, or other conflicting bits may be + * cleared. Spec is not strict here. Read NPEM Control register after + * write to keep cache in-sync. + */ + return npem_get_active_indications(npem, &npem->active_indications); +} + +static const struct npem_ops npem_ops = { + .get_active_indications = npem_get_active_indications, + .set_active_indications = npem_set_active_indications, + .name = "Native PCIe Enclosure Management", + .inds = npem_indications, +}; + +#define DSM_GUID GUID_INIT(0x5d524d9d, 0xfff9, 0x4d4b, 0x8c, 0xb7, 0x74, 0x7e,\ + 0xd5, 0x1e, 0x19, 0x4d) +#define GET_SUPPORTED_STATES_DSM 1 +#define GET_STATE_DSM 2 +#define SET_STATE_DSM 3 + +static const guid_t dsm_guid = DSM_GUID; + +static bool npem_has_dsm(struct pci_dev *pdev) +{ + acpi_handle handle; + + handle = ACPI_HANDLE(&pdev->dev); + if (!handle) + return false; + + return acpi_check_dsm(handle, &dsm_guid, 0x1, + BIT(GET_SUPPORTED_STATES_DSM) | + BIT(GET_STATE_DSM) | BIT(SET_STATE_DSM)); +} + +/* + * The status of each indicator is cached on first brightness_ get/set time + * and updated at write time. brightness_get() is only responsible for + * reflecting the last written/cached value. + */ +static enum led_brightness brightness_get(struct led_classdev *led) +{ + struct npem_led *nled = container_of(led, struct npem_led, led); + struct npem *npem = nled->npem; + int ret, val = 0; + + ret = mutex_lock_interruptible(&npem->lock); + if (ret) + return ret; + + if (npem->active_indications & nled->indication->bit) + val = 1; + + mutex_unlock(&npem->lock); + return val; +} + +static int brightness_set(struct led_classdev *led, + enum led_brightness brightness) +{ + struct npem_led *nled = container_of(led, struct npem_led, led); + struct npem *npem = nled->npem; + u32 indications; + int ret; + + ret = mutex_lock_interruptible(&npem->lock); + if (ret) + return ret; + + if (brightness == 0) + indications = npem->active_indications & ~(nled->indication->bit); + else + indications = npem->active_indications | nled->indication->bit; + + ret = npem->ops->set_active_indications(npem, indications); + + mutex_unlock(&npem->lock); + return ret; +} + +static void npem_free(struct npem *npem) +{ + struct npem_led *nled; + int cnt; + + if (!npem) + return; + + for (cnt = 0; cnt < npem->led_cnt; cnt++) { + nled = &npem->leds[cnt]; + + if (nled->name[0]) + led_classdev_unregister(&nled->led); + } + + mutex_destroy(&npem->lock); + kfree(npem); +} + +static int pci_npem_set_led_classdev(struct npem *npem, struct npem_led *nled) +{ + struct led_classdev *led = &nled->led; + struct led_init_data init_data = {}; + char *name = nled->name; + int ret; + + init_data.devicename = pci_name(npem->dev); + init_data.default_label = nled->indication->name; + + ret = led_compose_name(&npem->dev->dev, &init_data, name); + if (ret) + return ret; + + led->name = name; + led->brightness_set_blocking = brightness_set; + led->brightness_get = brightness_get; + led->max_brightness = 1; + led->default_trigger = "none"; + led->flags = 0; + + ret = led_classdev_register(&npem->dev->dev, led); + if (ret) + /* Clear the name to indicate that it is not registered. */ + name[0] = 0; + return ret; +} + +static int pci_npem_init(struct pci_dev *dev, const struct npem_ops *ops, + int pos, u32 caps) +{ + u32 supported = reg_to_indications(caps, ops->inds); + int supported_cnt = hweight32(supported); + const struct indication *indication; + struct npem_led *nled; + struct npem *npem; + int led_idx = 0; + int ret; + + npem = kzalloc(struct_size(npem, leds, supported_cnt), GFP_KERNEL); + if (!npem) + return -ENOMEM; + + npem->supported_indications = supported; + npem->led_cnt = supported_cnt; + npem->pos = pos; + npem->dev = dev; + npem->ops = ops; + + ret = npem->ops->get_active_indications(npem, + &npem->active_indications); + if (ret) + return ret; + + mutex_init(&npem->lock); + + for_each_indication(indication, npem_indications) { + if (!(npem->supported_indications & indication->bit)) + continue; + + nled = &npem->leds[led_idx++]; + nled->indication = indication; + nled->npem = npem; + + ret = pci_npem_set_led_classdev(npem, nled); + if (ret) { + npem_free(npem); + return ret; + } + } + + dev->npem = npem; + return 0; +} + +void pci_npem_remove(struct pci_dev *dev) +{ + npem_free(dev->npem); +} + +void pci_npem_create(struct pci_dev *dev) +{ + const struct npem_ops *ops = &npem_ops; + int pos = 0, ret; + u32 cap; + + if (npem_has_dsm(dev)) { + /* + * OS should use the DSM for LED control if it is available + * PCI Firmware Spec r3.3 sec 4.7. + */ + pci_info(dev, "Not configuring %s because _DSM is present\n", + ops->name); + return; + } else { + pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_NPEM); + if (pos == 0) + return; + + if (pci_read_config_dword(dev, pos + PCI_NPEM_CAP, &cap) != 0 || + (cap & PCI_NPEM_CAP_CAPABLE) == 0) + return; + } + + pci_info(dev, "Configuring %s\n", ops->name); + + ret = pci_npem_init(dev, ops, pos, cap); + if (ret) + pci_err(dev, "Failed to register %s, err: %d\n", ops->name, + ret); +} |