// SPDX-License-Identifier: GPL-2.0-only
/*
 * Support for dynamic reconfiguration for PCI, Memory, and CPU
 * Hotplug and Dynamic Logical Partitioning on RPA platforms.
 *
 * Copyright (C) 2009 Nathan Fontenot
 * Copyright (C) 2009 IBM Corporation
 */

#define pr_fmt(fmt)	"dlpar: " fmt

#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/slab.h>
#include <linux/of.h>

#include "of_helpers.h"
#include "pseries.h"

#include <asm/machdep.h>
#include <linux/uaccess.h>
#include <asm/rtas.h>
#include <asm/rtas-work-area.h>
#include <asm/prom.h>

static struct workqueue_struct *pseries_hp_wq;

struct pseries_hp_work {
	struct work_struct work;
	struct pseries_hp_errorlog *errlog;
};

struct cc_workarea {
	__be32	drc_index;
	__be32	zero;
	__be32	name_offset;
	__be32	prop_length;
	__be32	prop_offset;
};

void dlpar_free_cc_property(struct property *prop)
{
	kfree(prop->name);
	kfree(prop->value);
	kfree(prop);
}

static struct property *dlpar_parse_cc_property(struct cc_workarea *ccwa)
{
	struct property *prop;
	char *name;
	char *value;

	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
	if (!prop)
		return NULL;

	name = (char *)ccwa + be32_to_cpu(ccwa->name_offset);
	prop->name = kstrdup(name, GFP_KERNEL);
	if (!prop->name) {
		dlpar_free_cc_property(prop);
		return NULL;
	}

	prop->length = be32_to_cpu(ccwa->prop_length);
	value = (char *)ccwa + be32_to_cpu(ccwa->prop_offset);
	prop->value = kmemdup(value, prop->length, GFP_KERNEL);
	if (!prop->value) {
		dlpar_free_cc_property(prop);
		return NULL;
	}

	return prop;
}

static struct device_node *dlpar_parse_cc_node(struct cc_workarea *ccwa)
{
	struct device_node *dn;
	const char *name;

	dn = kzalloc(sizeof(*dn), GFP_KERNEL);
	if (!dn)
		return NULL;

	name = (const char *)ccwa + be32_to_cpu(ccwa->name_offset);
	dn->full_name = kstrdup(name, GFP_KERNEL);
	if (!dn->full_name) {
		kfree(dn);
		return NULL;
	}

	of_node_set_flag(dn, OF_DYNAMIC);
	of_node_init(dn);

	return dn;
}

static void dlpar_free_one_cc_node(struct device_node *dn)
{
	struct property *prop;

	while (dn->properties) {
		prop = dn->properties;
		dn->properties = prop->next;
		dlpar_free_cc_property(prop);
	}

	kfree(dn->full_name);
	kfree(dn);
}

void dlpar_free_cc_nodes(struct device_node *dn)
{
	if (dn->child)
		dlpar_free_cc_nodes(dn->child);

	if (dn->sibling)
		dlpar_free_cc_nodes(dn->sibling);

	dlpar_free_one_cc_node(dn);
}

#define COMPLETE	0
#define NEXT_SIBLING    1
#define NEXT_CHILD      2
#define NEXT_PROPERTY   3
#define PREV_PARENT     4
#define MORE_MEMORY     5
#define ERR_CFG_USE     -9003

struct device_node *dlpar_configure_connector(__be32 drc_index,
					      struct device_node *parent)
{
	struct device_node *dn;
	struct device_node *first_dn = NULL;
	struct device_node *last_dn = NULL;
	struct property *property;
	struct property *last_property = NULL;
	struct cc_workarea *ccwa;
	struct rtas_work_area *work_area;
	char *data_buf;
	int cc_token;
	int rc = -1;

	cc_token = rtas_function_token(RTAS_FN_IBM_CONFIGURE_CONNECTOR);
	if (cc_token == RTAS_UNKNOWN_SERVICE)
		return NULL;

	work_area = rtas_work_area_alloc(SZ_4K);
	data_buf = rtas_work_area_raw_buf(work_area);

	ccwa = (struct cc_workarea *)&data_buf[0];
	ccwa->drc_index = drc_index;
	ccwa->zero = 0;

	do {
		do {
			rc = rtas_call(cc_token, 2, 1, NULL,
				       rtas_work_area_phys(work_area), NULL);
		} while (rtas_busy_delay(rc));

		switch (rc) {
		case COMPLETE:
			break;

		case NEXT_SIBLING:
			dn = dlpar_parse_cc_node(ccwa);
			if (!dn)
				goto cc_error;

			dn->parent = last_dn->parent;
			last_dn->sibling = dn;
			last_dn = dn;
			break;

		case NEXT_CHILD:
			dn = dlpar_parse_cc_node(ccwa);
			if (!dn)
				goto cc_error;

			if (!first_dn) {
				dn->parent = parent;
				first_dn = dn;
			} else {
				dn->parent = last_dn;
				if (last_dn)
					last_dn->child = dn;
			}

			last_dn = dn;
			break;

		case NEXT_PROPERTY:
			property = dlpar_parse_cc_property(ccwa);
			if (!property)
				goto cc_error;

			if (!last_dn->properties)
				last_dn->properties = property;
			else
				last_property->next = property;

			last_property = property;
			break;

		case PREV_PARENT:
			last_dn = last_dn->parent;
			break;

		case MORE_MEMORY:
		case ERR_CFG_USE:
		default:
			printk(KERN_ERR "Unexpected Error (%d) "
			       "returned from configure-connector\n", rc);
			goto cc_error;
		}
	} while (rc);

cc_error:
	rtas_work_area_free(work_area);

	if (rc) {
		if (first_dn)
			dlpar_free_cc_nodes(first_dn);

		return NULL;
	}

	return first_dn;
}

int dlpar_attach_node(struct device_node *dn, struct device_node *parent)
{
	int rc;

	dn->parent = parent;

	rc = of_attach_node(dn);
	if (rc) {
		printk(KERN_ERR "Failed to add device node %pOF\n", dn);
		return rc;
	}

	return 0;
}

int dlpar_detach_node(struct device_node *dn)
{
	struct device_node *child;
	int rc;

	for_each_child_of_node(dn, child)
		dlpar_detach_node(child);

	rc = of_detach_node(dn);
	if (rc)
		return rc;

	of_node_put(dn);

	return 0;
}
static int dlpar_changeset_attach_cc_nodes(struct of_changeset *ocs,
					struct device_node *dn)
{
	int rc;

	rc = of_changeset_attach_node(ocs, dn);

	if (!rc && dn->child)
		rc = dlpar_changeset_attach_cc_nodes(ocs, dn->child);
	if (!rc && dn->sibling)
		rc = dlpar_changeset_attach_cc_nodes(ocs, dn->sibling);

	return rc;
}

#define DR_ENTITY_SENSE		9003
#define DR_ENTITY_PRESENT	1
#define DR_ENTITY_UNUSABLE	2
#define ALLOCATION_STATE	9003
#define ALLOC_UNUSABLE		0
#define ALLOC_USABLE		1
#define ISOLATION_STATE		9001
#define ISOLATE			0
#define UNISOLATE		1

int dlpar_acquire_drc(u32 drc_index)
{
	int dr_status, rc;

	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
	if (rc || dr_status != DR_ENTITY_UNUSABLE)
		return -1;

	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_USABLE);
	if (rc)
		return rc;

	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
	if (rc) {
		rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
		return rc;
	}

	return 0;
}

int dlpar_release_drc(u32 drc_index)
{
	int dr_status, rc;

	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
	if (rc || dr_status != DR_ENTITY_PRESENT)
		return -1;

	rc = rtas_set_indicator(ISOLATION_STATE, drc_index, ISOLATE);
	if (rc)
		return rc;

	rc = rtas_set_indicator(ALLOCATION_STATE, drc_index, ALLOC_UNUSABLE);
	if (rc) {
		rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);
		return rc;
	}

	return 0;
}

int dlpar_unisolate_drc(u32 drc_index)
{
	int dr_status, rc;

	rc = rtas_get_sensor(DR_ENTITY_SENSE, drc_index, &dr_status);
	if (rc || dr_status != DR_ENTITY_PRESENT)
		return -1;

	rtas_set_indicator(ISOLATION_STATE, drc_index, UNISOLATE);

	return 0;
}

static struct device_node *
get_device_node_with_drc_index(u32 index)
{
	struct device_node *np = NULL;
	u32 node_index;
	int rc;

	for_each_node_with_property(np, "ibm,my-drc-index") {
		rc = of_property_read_u32(np, "ibm,my-drc-index",
					     &node_index);
		if (rc) {
			pr_err("%s: %pOF: of_property_read_u32 %s: %d\n",
			       __func__, np, "ibm,my-drc-index", rc);
			of_node_put(np);
			return NULL;
		}

		if (index == node_index)
			break;
	}

	return np;
}

static struct device_node *
get_device_node_with_drc_info(u32 index)
{
	struct device_node *np = NULL;
	struct of_drc_info drc;
	struct property *info;
	const __be32 *value;
	u32 node_index;
	int i, j, count;

	for_each_node_with_property(np, "ibm,drc-info") {
		info = of_find_property(np, "ibm,drc-info", NULL);
		if (info == NULL) {
			/* XXX can this happen? */
			of_node_put(np);
			return NULL;
		}
		value = of_prop_next_u32(info, NULL, &count);
		if (value == NULL)
			continue;
		value++;
		for (i = 0; i < count; i++) {
			if (of_read_drc_info_cell(&info, &value, &drc))
				break;
			if (index > drc.last_drc_index)
				continue;
			node_index = drc.drc_index_start;
			for (j = 0; j < drc.num_sequential_elems; j++) {
				if (index == node_index)
					return np;
				node_index += drc.sequential_inc;
			}
		}
	}

	return NULL;
}

static int dlpar_hp_dt_add(u32 index)
{
	struct device_node *np, *nodes;
	struct of_changeset ocs;
	int rc;

	/*
	 * Do not add device node(s) if already exists in the
	 * device tree.
	 */
	np = get_device_node_with_drc_index(index);
	if (np) {
		pr_err("%s: Adding device node for index (%d), but "
				"already exists in the device tree\n",
				__func__, index);
		rc = -EINVAL;
		goto out;
	}

	np = get_device_node_with_drc_info(index);

	if (!np)
		return -EIO;

	/* Next, configure the connector. */
	nodes = dlpar_configure_connector(cpu_to_be32(index), np);
	if (!nodes) {
		rc = -EIO;
		goto out;
	}

	/*
	 * Add the new nodes from dlpar_configure_connector() onto
	 * the device-tree.
	 */
	of_changeset_init(&ocs);
	rc = dlpar_changeset_attach_cc_nodes(&ocs, nodes);

	if (!rc)
		rc = of_changeset_apply(&ocs);
	else
		dlpar_free_cc_nodes(nodes);

	of_changeset_destroy(&ocs);

out:
	of_node_put(np);
	return rc;
}

static int changeset_detach_node_recursive(struct of_changeset *ocs,
					struct device_node *node)
{
	struct device_node *child;
	int rc;

	for_each_child_of_node(node, child) {
		rc = changeset_detach_node_recursive(ocs, child);
		if (rc) {
			of_node_put(child);
			return rc;
		}
	}

	return of_changeset_detach_node(ocs, node);
}

static int dlpar_hp_dt_remove(u32 drc_index)
{
	struct device_node *np;
	struct of_changeset ocs;
	u32 index;
	int rc = 0;

	/*
	 * Prune all nodes with a matching index.
	 */
	of_changeset_init(&ocs);

	for_each_node_with_property(np, "ibm,my-drc-index") {
		rc = of_property_read_u32(np, "ibm,my-drc-index", &index);
		if (rc) {
			pr_err("%s: %pOF: of_property_read_u32 %s: %d\n",
				__func__, np, "ibm,my-drc-index", rc);
			of_node_put(np);
			goto out;
		}

		if (index == drc_index) {
			rc = changeset_detach_node_recursive(&ocs, np);
			if (rc) {
				of_node_put(np);
				goto out;
			}
		}
	}

	rc = of_changeset_apply(&ocs);

out:
	of_changeset_destroy(&ocs);
	return rc;
}

static int dlpar_hp_dt(struct pseries_hp_errorlog *phpe)
{
	u32 drc_index;
	int rc;

	if (phpe->id_type != PSERIES_HP_ELOG_ID_DRC_INDEX)
		return -EINVAL;

	drc_index = be32_to_cpu(phpe->_drc_u.drc_index);

	lock_device_hotplug();

	switch (phpe->action) {
	case PSERIES_HP_ELOG_ACTION_ADD:
		rc = dlpar_hp_dt_add(drc_index);
		break;
	case PSERIES_HP_ELOG_ACTION_REMOVE:
		rc = dlpar_hp_dt_remove(drc_index);
		break;
	default:
		pr_err("Invalid action (%d) specified\n", phpe->action);
		rc = -EINVAL;
		break;
	}

	unlock_device_hotplug();

	return rc;
}

int handle_dlpar_errorlog(struct pseries_hp_errorlog *hp_elog)
{
	int rc;

	switch (hp_elog->resource) {
	case PSERIES_HP_ELOG_RESOURCE_MEM:
		rc = dlpar_memory(hp_elog);
		break;
	case PSERIES_HP_ELOG_RESOURCE_CPU:
		rc = dlpar_cpu(hp_elog);
		break;
	case PSERIES_HP_ELOG_RESOURCE_PMEM:
		rc = dlpar_hp_pmem(hp_elog);
		break;
	case PSERIES_HP_ELOG_RESOURCE_DT:
		rc = dlpar_hp_dt(hp_elog);
		break;

	default:
		pr_warn_ratelimited("Invalid resource (%d) specified\n",
				    hp_elog->resource);
		rc = -EINVAL;
	}

	return rc;
}

static void pseries_hp_work_fn(struct work_struct *work)
{
	struct pseries_hp_work *hp_work =
			container_of(work, struct pseries_hp_work, work);

	handle_dlpar_errorlog(hp_work->errlog);

	kfree(hp_work->errlog);
	kfree(work);
}

void queue_hotplug_event(struct pseries_hp_errorlog *hp_errlog)
{
	struct pseries_hp_work *work;
	struct pseries_hp_errorlog *hp_errlog_copy;

	hp_errlog_copy = kmemdup(hp_errlog, sizeof(*hp_errlog), GFP_ATOMIC);
	if (!hp_errlog_copy)
		return;

	work = kmalloc(sizeof(struct pseries_hp_work), GFP_ATOMIC);
	if (work) {
		INIT_WORK((struct work_struct *)work, pseries_hp_work_fn);
		work->errlog = hp_errlog_copy;
		queue_work(pseries_hp_wq, (struct work_struct *)work);
	} else {
		kfree(hp_errlog_copy);
	}
}

static int dlpar_parse_resource(char **cmd, struct pseries_hp_errorlog *hp_elog)
{
	char *arg;

	arg = strsep(cmd, " ");
	if (!arg)
		return -EINVAL;

	if (sysfs_streq(arg, "memory")) {
		hp_elog->resource = PSERIES_HP_ELOG_RESOURCE_MEM;
	} else if (sysfs_streq(arg, "cpu")) {
		hp_elog->resource = PSERIES_HP_ELOG_RESOURCE_CPU;
	} else if (sysfs_streq(arg, "dt")) {
		hp_elog->resource = PSERIES_HP_ELOG_RESOURCE_DT;
	} else {
		pr_err("Invalid resource specified.\n");
		return -EINVAL;
	}

	return 0;
}

static int dlpar_parse_action(char **cmd, struct pseries_hp_errorlog *hp_elog)
{
	char *arg;

	arg = strsep(cmd, " ");
	if (!arg)
		return -EINVAL;

	if (sysfs_streq(arg, "add")) {
		hp_elog->action = PSERIES_HP_ELOG_ACTION_ADD;
	} else if (sysfs_streq(arg, "remove")) {
		hp_elog->action = PSERIES_HP_ELOG_ACTION_REMOVE;
	} else {
		pr_err("Invalid action specified.\n");
		return -EINVAL;
	}

	return 0;
}

static int dlpar_parse_id_type(char **cmd, struct pseries_hp_errorlog *hp_elog)
{
	char *arg;
	u32 count, index;

	arg = strsep(cmd, " ");
	if (!arg)
		return -EINVAL;

	if (sysfs_streq(arg, "indexed-count")) {
		hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_IC;
		arg = strsep(cmd, " ");
		if (!arg) {
			pr_err("No DRC count specified.\n");
			return -EINVAL;
		}

		if (kstrtou32(arg, 0, &count)) {
			pr_err("Invalid DRC count specified.\n");
			return -EINVAL;
		}

		arg = strsep(cmd, " ");
		if (!arg) {
			pr_err("No DRC Index specified.\n");
			return -EINVAL;
		}

		if (kstrtou32(arg, 0, &index)) {
			pr_err("Invalid DRC Index specified.\n");
			return -EINVAL;
		}

		hp_elog->_drc_u.ic.count = cpu_to_be32(count);
		hp_elog->_drc_u.ic.index = cpu_to_be32(index);
	} else if (sysfs_streq(arg, "index")) {
		hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
		arg = strsep(cmd, " ");
		if (!arg) {
			pr_err("No DRC Index specified.\n");
			return -EINVAL;
		}

		if (kstrtou32(arg, 0, &index)) {
			pr_err("Invalid DRC Index specified.\n");
			return -EINVAL;
		}

		hp_elog->_drc_u.drc_index = cpu_to_be32(index);
	} else if (sysfs_streq(arg, "count")) {
		hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_COUNT;
		arg = strsep(cmd, " ");
		if (!arg) {
			pr_err("No DRC count specified.\n");
			return -EINVAL;
		}

		if (kstrtou32(arg, 0, &count)) {
			pr_err("Invalid DRC count specified.\n");
			return -EINVAL;
		}

		hp_elog->_drc_u.drc_count = cpu_to_be32(count);
	} else {
		pr_err("Invalid id_type specified.\n");
		return -EINVAL;
	}

	return 0;
}

static ssize_t dlpar_store(const struct class *class, const struct class_attribute *attr,
			   const char *buf, size_t count)
{
	struct pseries_hp_errorlog hp_elog;
	char *argbuf;
	char *args;
	int rc;

	args = argbuf = kstrdup(buf, GFP_KERNEL);
	if (!argbuf)
		return -ENOMEM;

	/*
	 * Parse out the request from the user, this will be in the form:
	 * <resource> <action> <id_type> <id>
	 */
	rc = dlpar_parse_resource(&args, &hp_elog);
	if (rc)
		goto dlpar_store_out;

	rc = dlpar_parse_action(&args, &hp_elog);
	if (rc)
		goto dlpar_store_out;

	rc = dlpar_parse_id_type(&args, &hp_elog);
	if (rc)
		goto dlpar_store_out;

	rc = handle_dlpar_errorlog(&hp_elog);

dlpar_store_out:
	kfree(argbuf);

	if (rc)
		pr_err("Could not handle DLPAR request \"%s\"\n", buf);

	return rc ? rc : count;
}

static ssize_t dlpar_show(const struct class *class, const struct class_attribute *attr,
			  char *buf)
{
	return sprintf(buf, "%s\n", "memory,cpu,dt");
}

static CLASS_ATTR_RW(dlpar);

int __init dlpar_workqueue_init(void)
{
	if (pseries_hp_wq)
		return 0;

	pseries_hp_wq = alloc_ordered_workqueue("pseries hotplug workqueue", 0);

	return pseries_hp_wq ? 0 : -ENOMEM;
}

static int __init dlpar_sysfs_init(void)
{
	int rc;

	rc = dlpar_workqueue_init();
	if (rc)
		return rc;

	return sysfs_create_file(kernel_kobj, &class_attr_dlpar.attr);
}
machine_device_initcall(pseries, dlpar_sysfs_init);