// SPDX-License-Identifier: GPL-2.0
/*
 * Intel Platform Monitoring Technology Crashlog driver
 *
 * Copyright (c) 2020, Intel Corporation.
 * All Rights Reserved.
 *
 * Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
 */

#include <linux/auxiliary_bus.h>
#include <linux/cleanup.h>
#include <linux/intel_vsec.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/overflow.h>

#include "class.h"

/* Crashlog discovery header types */
#define CRASH_TYPE_OOBMSM	1

/* Crashlog Discovery Header */
#define CONTROL_OFFSET		0x0
#define GUID_OFFSET		0x4
#define BASE_OFFSET		0x8
#define SIZE_OFFSET		0xC
#define GET_ACCESS(v)		((v) & GENMASK(3, 0))
#define GET_TYPE(v)		(((v) & GENMASK(7, 4)) >> 4)
#define GET_VERSION(v)		(((v) & GENMASK(19, 16)) >> 16)
/* size is in bytes */
#define GET_SIZE(v)		((v) * sizeof(u32))

/*
 * Type 1 Version 0
 * status and control registers are combined.
 *
 * Bits 29 and 30 control the state of bit 31.
 * Bit 29 will clear bit 31, if set, allowing a new crashlog to be captured.
 * Bit 30 will immediately trigger a crashlog to be generated, setting bit 31.
 * Bit 31 is the read-only status with a 1 indicating log is complete.
 */
#define TYPE1_VER0_STATUS_OFFSET	0x00
#define TYPE1_VER0_CONTROL_OFFSET	0x00

#define TYPE1_VER0_DISABLE		BIT(28)
#define TYPE1_VER0_CLEAR		BIT(29)
#define TYPE1_VER0_EXECUTE		BIT(30)
#define TYPE1_VER0_COMPLETE		BIT(31)
#define TYPE1_VER0_TRIGGER_MASK		GENMASK(31, 28)

/*
 * Type 1 Version 2
 * status and control are different registers
 */
#define TYPE1_VER2_STATUS_OFFSET	0x00
#define TYPE1_VER2_CONTROL_OFFSET	0x14

/* status register */
#define TYPE1_VER2_CLEAR_SUPPORT	BIT(20)
#define TYPE1_VER2_REARMED		BIT(25)
#define TYPE1_VER2_ERROR		BIT(26)
#define TYPE1_VER2_CONSUMED		BIT(27)
#define TYPE1_VER2_DISABLED		BIT(28)
#define TYPE1_VER2_CLEARED		BIT(29)
#define TYPE1_VER2_IN_PROGRESS		BIT(30)
#define TYPE1_VER2_COMPLETE		BIT(31)

/* control register */
#define TYPE1_VER2_CONSUME		BIT(25)
#define TYPE1_VER2_REARM		BIT(28)
#define TYPE1_VER2_EXECUTE		BIT(29)
#define TYPE1_VER2_CLEAR		BIT(30)
#define TYPE1_VER2_DISABLE		BIT(31)
#define TYPE1_VER2_TRIGGER_MASK	\
	(TYPE1_VER2_EXECUTE | TYPE1_VER2_CLEAR | TYPE1_VER2_DISABLE)

/* After offset, order alphabetically, not bit ordered */
struct crashlog_status {
	u32 offset;
	u32 clear_supported;
	u32 cleared;
	u32 complete;
	u32 consumed;
	u32 disabled;
	u32 error;
	u32 in_progress;
	u32 rearmed;
};

struct crashlog_control {
	u32 offset;
	u32 trigger_mask;
	u32 clear;
	u32 consume;
	u32 disable;
	u32 manual;
	u32 rearm;
};

struct crashlog_info {
	const struct crashlog_status status;
	const struct crashlog_control control;
	const struct attribute_group *attr_grp;
};

struct crashlog_entry {
	/* entry must be first member of struct */
	struct intel_pmt_entry		entry;
	struct mutex			control_mutex;
	const struct crashlog_info	*info;
};

struct pmt_crashlog_priv {
	int			num_entries;
	struct crashlog_entry	entry[];
};

/*
 * I/O
 */

/* Read, modify, write the control register, setting or clearing @bit based on @set */
static void pmt_crashlog_rmw(struct crashlog_entry *crashlog, u32 bit, bool set)
{
	const struct crashlog_control *control = &crashlog->info->control;
	struct intel_pmt_entry *entry = &crashlog->entry;
	u32 reg = readl(entry->disc_table + control->offset);

	reg &= ~control->trigger_mask;

	if (set)
		reg |= bit;
	else
		reg &= ~bit;

	writel(reg, entry->disc_table + control->offset);
}

/* Read the status register and see if the specified @bit is set */
static bool pmt_crashlog_rc(struct crashlog_entry *crashlog, u32 bit)
{
	const struct crashlog_status *status = &crashlog->info->status;
	u32 reg = readl(crashlog->entry.disc_table + status->offset);

	return !!(reg & bit);
}

static bool pmt_crashlog_complete(struct crashlog_entry *crashlog)
{
	/* return current value of the crashlog complete flag */
	return pmt_crashlog_rc(crashlog, crashlog->info->status.complete);
}

static bool pmt_crashlog_disabled(struct crashlog_entry *crashlog)
{
	/* return current value of the crashlog disabled flag */
	return pmt_crashlog_rc(crashlog, crashlog->info->status.disabled);
}

static bool pmt_crashlog_supported(struct intel_pmt_entry *entry, u32 *crash_type, u32 *version)
{
	u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);

	*crash_type = GET_TYPE(discovery_header);
	*version = GET_VERSION(discovery_header);

	/*
	 * Currently we only recognize OOBMSM (type 1) and version 0 or 2
	 * devices.
	 *
	 * Ignore all other crashlog devices in the system.
	 */
	if (*crash_type == CRASH_TYPE_OOBMSM && (*version == 0 || *version == 2))
		return true;

	return false;
}

static void pmt_crashlog_set_disable(struct crashlog_entry *crashlog,
				     bool disable)
{
	pmt_crashlog_rmw(crashlog, crashlog->info->control.disable, disable);
}

static void pmt_crashlog_set_clear(struct crashlog_entry *crashlog)
{
	pmt_crashlog_rmw(crashlog, crashlog->info->control.clear, true);
}

static void pmt_crashlog_set_execute(struct crashlog_entry *crashlog)
{
	pmt_crashlog_rmw(crashlog, crashlog->info->control.manual, true);
}

static bool pmt_crashlog_cleared(struct crashlog_entry *crashlog)
{
	return pmt_crashlog_rc(crashlog, crashlog->info->status.cleared);
}

static bool pmt_crashlog_consumed(struct crashlog_entry *crashlog)
{
	return pmt_crashlog_rc(crashlog, crashlog->info->status.consumed);
}

static void pmt_crashlog_set_consumed(struct crashlog_entry *crashlog)
{
	pmt_crashlog_rmw(crashlog, crashlog->info->control.consume, true);
}

static bool pmt_crashlog_error(struct crashlog_entry *crashlog)
{
	return pmt_crashlog_rc(crashlog, crashlog->info->status.error);
}

static bool pmt_crashlog_rearm(struct crashlog_entry *crashlog)
{
	return pmt_crashlog_rc(crashlog, crashlog->info->status.rearmed);
}

static void pmt_crashlog_set_rearm(struct crashlog_entry *crashlog)
{
	pmt_crashlog_rmw(crashlog, crashlog->info->control.rearm, true);
}

/*
 * sysfs
 */
static ssize_t
clear_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog = dev_get_drvdata(dev);
	bool cleared = pmt_crashlog_cleared(crashlog);

	return sysfs_emit(buf, "%d\n", cleared);
}

static ssize_t
clear_store(struct device *dev, struct device_attribute *attr,
	    const char *buf, size_t count)
{
	struct crashlog_entry *crashlog;
	bool clear;
	int result;

	crashlog = dev_get_drvdata(dev);

	result = kstrtobool(buf, &clear);
	if (result)
		return result;

	/* set bit only */
	if (!clear)
		return -EINVAL;

	guard(mutex)(&crashlog->control_mutex);

	pmt_crashlog_set_clear(crashlog);

	return count;
}
static DEVICE_ATTR_RW(clear);

static ssize_t
consumed_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog = dev_get_drvdata(dev);
	bool consumed = pmt_crashlog_consumed(crashlog);

	return sysfs_emit(buf, "%d\n", consumed);
}

static ssize_t
consumed_store(struct device *dev, struct device_attribute *attr, const char *buf,
	       size_t count)
{
	struct crashlog_entry *crashlog;
	bool consumed;
	int result;

	crashlog = dev_get_drvdata(dev);

	result = kstrtobool(buf, &consumed);
	if (result)
		return result;

	/* set bit only */
	if (!consumed)
		return -EINVAL;

	guard(mutex)(&crashlog->control_mutex);

	if (pmt_crashlog_disabled(crashlog))
		return -EBUSY;

	if (!pmt_crashlog_complete(crashlog))
		return -EEXIST;

	pmt_crashlog_set_consumed(crashlog);

	return count;
}
static DEVICE_ATTR_RW(consumed);

static ssize_t
enable_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog = dev_get_drvdata(dev);
	bool enabled = !pmt_crashlog_disabled(crashlog);

	return sprintf(buf, "%d\n", enabled);
}

static ssize_t
enable_store(struct device *dev, struct device_attribute *attr,
	     const char *buf, size_t count)
{
	struct crashlog_entry *crashlog;
	bool enabled;
	int result;

	crashlog = dev_get_drvdata(dev);

	result = kstrtobool(buf, &enabled);
	if (result)
		return result;

	guard(mutex)(&crashlog->control_mutex);

	pmt_crashlog_set_disable(crashlog, !enabled);

	return count;
}
static DEVICE_ATTR_RW(enable);

static ssize_t
error_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog = dev_get_drvdata(dev);
	bool error = pmt_crashlog_error(crashlog);

	return sysfs_emit(buf, "%d\n", error);
}
static DEVICE_ATTR_RO(error);

static ssize_t
rearm_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog = dev_get_drvdata(dev);
	int rearmed = pmt_crashlog_rearm(crashlog);

	return sysfs_emit(buf, "%d\n", rearmed);
}

static ssize_t
rearm_store(struct device *dev, struct device_attribute *attr, const char *buf,
	    size_t count)
{
	struct crashlog_entry *crashlog;
	bool rearm;
	int result;

	crashlog = dev_get_drvdata(dev);

	result = kstrtobool(buf, &rearm);
	if (result)
		return result;

	/* set only */
	if (!rearm)
		return -EINVAL;

	guard(mutex)(&crashlog->control_mutex);

	pmt_crashlog_set_rearm(crashlog);

	return count;
}
static DEVICE_ATTR_RW(rearm);

static ssize_t
trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct crashlog_entry *crashlog;
	bool trigger;

	crashlog = dev_get_drvdata(dev);
	trigger = pmt_crashlog_complete(crashlog);

	return sprintf(buf, "%d\n", trigger);
}

static ssize_t
trigger_store(struct device *dev, struct device_attribute *attr,
	      const char *buf, size_t count)
{
	struct crashlog_entry *crashlog;
	bool trigger;
	int result;

	crashlog = dev_get_drvdata(dev);

	result = kstrtobool(buf, &trigger);
	if (result)
		return result;

	guard(mutex)(&crashlog->control_mutex);

	/* if device is currently disabled, return busy */
	if (pmt_crashlog_disabled(crashlog))
		return -EBUSY;

	if (!trigger) {
		pmt_crashlog_set_clear(crashlog);
		return count;
	}

	/* we cannot trigger a new crash if one is still pending */
	if (pmt_crashlog_complete(crashlog))
		return -EEXIST;

	pmt_crashlog_set_execute(crashlog);

	return count;
}
static DEVICE_ATTR_RW(trigger);

static struct attribute *pmt_crashlog_type1_ver0_attrs[] = {
	&dev_attr_enable.attr,
	&dev_attr_trigger.attr,
	NULL
};

static struct attribute *pmt_crashlog_type1_ver2_attrs[] = {
	&dev_attr_clear.attr,
	&dev_attr_consumed.attr,
	&dev_attr_enable.attr,
	&dev_attr_error.attr,
	&dev_attr_rearm.attr,
	&dev_attr_trigger.attr,
	NULL
};

static const struct attribute_group pmt_crashlog_type1_ver0_group = {
	.attrs	= pmt_crashlog_type1_ver0_attrs,
};

static const struct attribute_group pmt_crashlog_type1_ver2_group = {
	.attrs = pmt_crashlog_type1_ver2_attrs,
};

static const struct crashlog_info crashlog_type1_ver0 = {
	.status.offset = TYPE1_VER0_STATUS_OFFSET,
	.status.cleared = TYPE1_VER0_CLEAR,
	.status.complete = TYPE1_VER0_COMPLETE,
	.status.disabled = TYPE1_VER0_DISABLE,

	.control.offset = TYPE1_VER0_CONTROL_OFFSET,
	.control.trigger_mask = TYPE1_VER0_TRIGGER_MASK,
	.control.clear = TYPE1_VER0_CLEAR,
	.control.disable = TYPE1_VER0_DISABLE,
	.control.manual = TYPE1_VER0_EXECUTE,
	.attr_grp = &pmt_crashlog_type1_ver0_group,
};

static const struct crashlog_info crashlog_type1_ver2 = {
	.status.offset = TYPE1_VER2_STATUS_OFFSET,
	.status.clear_supported = TYPE1_VER2_CLEAR_SUPPORT,
	.status.cleared = TYPE1_VER2_CLEARED,
	.status.complete = TYPE1_VER2_COMPLETE,
	.status.consumed = TYPE1_VER2_CONSUMED,
	.status.disabled = TYPE1_VER2_DISABLED,
	.status.error = TYPE1_VER2_ERROR,
	.status.in_progress = TYPE1_VER2_IN_PROGRESS,
	.status.rearmed = TYPE1_VER2_REARMED,

	.control.offset = TYPE1_VER2_CONTROL_OFFSET,
	.control.trigger_mask = TYPE1_VER2_TRIGGER_MASK,
	.control.clear = TYPE1_VER2_CLEAR,
	.control.consume = TYPE1_VER2_CONSUME,
	.control.disable = TYPE1_VER2_DISABLE,
	.control.manual = TYPE1_VER2_EXECUTE,
	.control.rearm = TYPE1_VER2_REARM,
	.attr_grp = &pmt_crashlog_type1_ver2_group,
};

static const struct crashlog_info *select_crashlog_info(u32 type, u32 version)
{
	if (version == 0)
		return &crashlog_type1_ver0;

	return &crashlog_type1_ver2;
}

static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
				      struct device *dev)
{
	void __iomem *disc_table = entry->disc_table;
	struct intel_pmt_header *header = &entry->header;
	struct crashlog_entry *crashlog;
	u32 version;
	u32 type;

	if (!pmt_crashlog_supported(entry, &type, &version))
		return 1;

	/* initialize the crashlog struct */
	crashlog = container_of(entry, struct crashlog_entry, entry);
	mutex_init(&crashlog->control_mutex);

	crashlog->info = select_crashlog_info(type, version);

	header->access_type = GET_ACCESS(readl(disc_table));
	header->guid = readl(disc_table + GUID_OFFSET);
	header->base_offset = readl(disc_table + BASE_OFFSET);

	/* Size is measured in DWORDS, but accessor returns bytes */
	header->size = GET_SIZE(readl(disc_table + SIZE_OFFSET));

	entry->attr_grp = crashlog->info->attr_grp;

	return 0;
}

static DEFINE_XARRAY_ALLOC(crashlog_array);
static struct intel_pmt_namespace pmt_crashlog_ns = {
	.name = "crashlog",
	.xa = &crashlog_array,
	.pmt_header_decode = pmt_crashlog_header_decode,
};

/*
 * initialization
 */
static void pmt_crashlog_remove(struct auxiliary_device *auxdev)
{
	struct pmt_crashlog_priv *priv = auxiliary_get_drvdata(auxdev);
	int i;

	for (i = 0; i < priv->num_entries; i++) {
		struct crashlog_entry *crashlog = &priv->entry[i];

		intel_pmt_dev_destroy(&crashlog->entry, &pmt_crashlog_ns);
		mutex_destroy(&crashlog->control_mutex);
	}
}

static int pmt_crashlog_probe(struct auxiliary_device *auxdev,
			      const struct auxiliary_device_id *id)
{
	struct intel_vsec_device *intel_vsec_dev = auxdev_to_ivdev(auxdev);
	struct pmt_crashlog_priv *priv;
	size_t size;
	int i, ret;

	size = struct_size(priv, entry, intel_vsec_dev->num_resources);
	priv = devm_kzalloc(&auxdev->dev, size, GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	auxiliary_set_drvdata(auxdev, priv);

	for (i = 0; i < intel_vsec_dev->num_resources; i++) {
		struct intel_pmt_entry *entry = &priv->entry[priv->num_entries].entry;

		ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, intel_vsec_dev, i);
		if (ret < 0)
			goto abort_probe;
		if (ret)
			continue;

		priv->num_entries++;
	}

	return 0;
abort_probe:
	pmt_crashlog_remove(auxdev);
	return ret;
}

static const struct auxiliary_device_id pmt_crashlog_id_table[] = {
	{ .name = "intel_vsec.crashlog" },
	{}
};
MODULE_DEVICE_TABLE(auxiliary, pmt_crashlog_id_table);

static struct auxiliary_driver pmt_crashlog_aux_driver = {
	.id_table	= pmt_crashlog_id_table,
	.remove		= pmt_crashlog_remove,
	.probe		= pmt_crashlog_probe,
};

static int __init pmt_crashlog_init(void)
{
	return auxiliary_driver_register(&pmt_crashlog_aux_driver);
}

static void __exit pmt_crashlog_exit(void)
{
	auxiliary_driver_unregister(&pmt_crashlog_aux_driver);
	xa_destroy(&crashlog_array);
}

module_init(pmt_crashlog_init);
module_exit(pmt_crashlog_exit);

MODULE_AUTHOR("Alexander Duyck <alexander.h.duyck@linux.intel.com>");
MODULE_DESCRIPTION("Intel PMT Crashlog driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("INTEL_PMT");