Merge branch 'pci/npem'

- Initialize leds class earlier (with an unfortunate Makefile ordering
  change) so the PCI NPEM driver can use it (Mariusz Tkaczyk)

- Add Native PCIe Enclosure Management (NPEM) support for sysfs control of
  NVMe RAID storage indicators (ok/fail/locate/rebuild/etc) (Mariusz
  Tkaczyk)

- Add support for the ACPI _DSM PCIe SSD status LED management, which is
  functionally similar to NPEM but mediated by platform firmware (Mariusz
  Tkaczyk)

* pci/npem:
  PCI/NPEM: Add _DSM PCIe SSD status LED management
  PCI/NPEM: Add Native PCIe Enclosure Management support
  leds: Init leds class earlier

6 files changed, 617 insertions, 0 deletions

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index aa4d1833f442..0d94e4a967d8 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -143,6 +143,15 @@ config PCI_IOV
 
 	  If unsure, say N.
 
+config PCI_NPEM
+	bool "Native PCIe Enclosure Management"
+	depends on LEDS_CLASS=y
+	help
+	  Support for Native PCIe Enclosure Management. It allows managing LED
+	  indications in storage enclosures. Enclosure must support following
+	  indications: OK, Locate, Fail, Rebuild, other indications are
+	  optional.
+
 config PCI_PRI
 	bool "PCI PRI support"
 	select PCI_ATS
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 8ddad57934a6..374c5c06d92f 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_XEN_PCIDEV_FRONTEND) += xen-pcifront.o
 obj-$(CONFIG_VGA_ARB)		+= vgaarb.o
 obj-$(CONFIG_PCI_DOE)		+= doe.o
 obj-$(CONFIG_PCI_DYNAMIC_OF_NODES) += of_property.o
+obj-$(CONFIG_PCI_NPEM)		+= npem.o
 
 # Endpoint library must be initialized before its users
 obj-$(CONFIG_PCI_ENDPOINT)	+= endpoint/
diff --git a/drivers/pci/npem.c b/drivers/pci/npem.c
new file mode 100644
index 000000000000..97507e0df769
--- /dev/null
+++ b/drivers/pci/npem.c
@@ -0,0 +1,595 @@
+// 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
+ *
+ * _DSM Definitions for PCIe SSD Status LED
+ *	 PCI Firmware Specification, r3.3 sec 4.7
+ *
+ * Two backends are supported to manipulate indications: Direct NPEM register
+ * access (npem_ops) and indirect access through the ACPI _DSM (dsm_ops).
+ * _DSM is used if supported, else NPEM.
+ *
+ * Copyright (c) 2021-2022 Dell Inc.
+ * 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}
+};
+
+/* _DSM PCIe SSD LED States correspond to NPEM register values */
+static const struct indication dsm_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"},
+	{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
+ * @active_inds_initialized: whether @active_indications has been initialized;
+ *	On Dell platforms, it is required that IPMI drivers are loaded before
+ *	the GET_STATE_DSM method is invoked: They use an IPMI OpRegion to
+ *	get/set the active LEDs. By initializing @active_indications lazily
+ *	(on first access to an LED), IPMI drivers are given a chance to load.
+ *	If they are not loaded in time, users will see various errors on LED
+ *	access in dmesg. Once they are loaded, the errors go away and LED
+ *	access becomes possible.
+ * @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;
+	unsigned int active_inds_initialized:1;
+	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));
+}
+
+struct dsm_output {
+	u16 status;
+	u8 function_specific_err;
+	u8 vendor_specific_err;
+	u32 state;
+};
+
+/**
+ * dsm_evaluate() - send DSM PCIe SSD Status LED command
+ * @pdev: PCI device
+ * @dsm_func: DSM LED Function
+ * @output: buffer to copy DSM Response
+ * @value_to_set: value for SET_STATE_DSM function
+ *
+ * To not bother caller with ACPI context, the returned _DSM Output Buffer is
+ * copied.
+ */
+static int dsm_evaluate(struct pci_dev *pdev, u64 dsm_func,
+			struct dsm_output *output, u32 value_to_set)
+{
+	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
+	union acpi_object *out_obj, arg3[2];
+	union acpi_object *arg3_p = NULL;
+
+	if (dsm_func == SET_STATE_DSM) {
+		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_to_set;
+
+		arg3_p = arg3;
+	}
+
+	out_obj = acpi_evaluate_dsm_typed(handle, &dsm_guid, 0x1, dsm_func,
+					  arg3_p, ACPI_TYPE_BUFFER);
+	if (!out_obj)
+		return -EIO;
+
+	if (out_obj->buffer.length < sizeof(struct dsm_output)) {
+		ACPI_FREE(out_obj);
+		return -EIO;
+	}
+
+	memcpy(output, out_obj->buffer.pointer, sizeof(struct dsm_output));
+
+	ACPI_FREE(out_obj);
+	return 0;
+}
+
+static int dsm_get(struct pci_dev *pdev, u64 dsm_func, u32 *buf)
+{
+	struct dsm_output output;
+	int ret = dsm_evaluate(pdev, dsm_func, &output, 0);
+
+	if (ret)
+		return ret;
+
+	if (output.status != 0)
+		return -EIO;
+
+	*buf = output.state;
+	return 0;
+}
+
+static int dsm_get_active_indications(struct npem *npem, u32 *buf)
+{
+	int ret = dsm_get(npem->dev, GET_STATE_DSM, buf);
+
+	/* Filter out not supported indications in response */
+	*buf &= npem->supported_indications;
+	return ret;
+}
+
+static int dsm_set_active_indications(struct npem *npem, u32 value)
+{
+	struct dsm_output output;
+	int ret = dsm_evaluate(npem->dev, SET_STATE_DSM, &output, value);
+
+	if (ret)
+		return ret;
+
+	switch (output.status) {
+	case 4:
+		/*
+		 * Not all bits are set. If this bit is set, the platform
+		 * disregarded some or all of the request state changes. OSPM
+		 * should check the resulting PCIe SSD Status LED States to see
+		 * what, if anything, has changed.
+		 *
+		 * PCI Firmware Specification, r3.3 Table 4-19.
+		 */
+		if (output.function_specific_err != 1)
+			return -EIO;
+		fallthrough;
+	case 0:
+		break;
+	default:
+		return -EIO;
+	}
+
+	npem->active_indications = output.state;
+
+	return 0;
+}
+
+static const struct npem_ops dsm_ops = {
+	.get_active_indications = dsm_get_active_indications,
+	.set_active_indications = dsm_set_active_indications,
+	.name = "_DSM PCIe SSD Status LED Management",
+	.inds = dsm_indications,
+};
+
+static int npem_initialize_active_indications(struct npem *npem)
+{
+	int ret;
+
+	lockdep_assert_held(&npem->lock);
+
+	if (npem->active_inds_initialized)
+		return 0;
+
+	ret = npem->ops->get_active_indications(npem,
+						&npem->active_indications);
+	if (ret)
+		return ret;
+
+	npem->active_inds_initialized = true;
+	return 0;
+}
+
+/*
+ * 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;
+
+	ret = npem_initialize_active_indications(npem);
+	if (ret)
+		goto out;
+
+	if (npem->active_indications & nled->indication->bit)
+		val = 1;
+
+out:
+	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;
+
+	ret = npem_initialize_active_indications(npem);
+	if (ret)
+		goto out;
+
+	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);
+
+out:
+	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;
+
+	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.
+		 */
+		ret = dsm_get(dev, GET_SUPPORTED_STATES_DSM, &cap);
+		if (ret)
+			return;
+
+		ops = &dsm_ops;
+	} 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);
+}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 665c3b937a55..2f93ecec468b 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -403,6 +403,14 @@ static inline void pci_doe_destroy(struct pci_dev *pdev) { }
 static inline void pci_doe_disconnected(struct pci_dev *pdev) { }
 #endif
 
+#ifdef CONFIG_PCI_NPEM
+void pci_npem_create(struct pci_dev *dev);
+void pci_npem_remove(struct pci_dev *dev);
+#else
+static inline void pci_npem_create(struct pci_dev *dev) { }
+static inline void pci_npem_remove(struct pci_dev *dev) { }
+#endif
+
 /**
  * pci_dev_set_io_state - Set the new error state if possible.
  *
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index e79d9bea32bf..747b4f9789ff 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2590,6 +2590,8 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	dev->match_driver = false;
 	ret = device_add(&dev->dev);
 	WARN_ON(ret < 0);
+
+	pci_npem_create(dev);
 }
 
 struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 910387e5bdbf..da9629c3a688 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -34,6 +34,8 @@ static void pci_destroy_dev(struct pci_dev *dev)
 	if (!dev->dev.kobj.parent)
 		return;
 
+	pci_npem_remove(dev);
+
 	device_del(&dev->dev);
 
 	down_write(&pci_bus_sem);