// SPDX-License-Identifier: GPL-2.0
/*
* Intel Platform Monitoring Technology Crashlog driver
*
* Copyright (c) 2020, Intel Corporation.
* All Rights Reserved.
*
* Author: "Alexander Duyck" <[email protected]>
*/
#include <linux/auxiliary_bus.h>
#include <linux/intel_vsec.h>
#include <linux/kernel.h>
#include <linux/module.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
/* Control Flags */
#define CRASHLOG_FLAG_DISABLE BIT(28)
/*
* 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 CRASHLOG_FLAG_TRIGGER_CLEAR BIT(29)
#define CRASHLOG_FLAG_TRIGGER_EXECUTE BIT(30)
#define CRASHLOG_FLAG_TRIGGER_COMPLETE BIT(31)
#define CRASHLOG_FLAG_TRIGGER_MASK GENMASK(31, 28)
/* 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))
struct crashlog_entry {
/* entry must be first member of struct */
struct intel_pmt_entry entry;
struct mutex control_mutex;
};
struct pmt_crashlog_priv {
int num_entries;
struct crashlog_entry entry[];
};
/*
* I/O
*/
static bool pmt_crashlog_complete(struct intel_pmt_entry *entry)
{
u32 control = readl(entry->disc_table + CONTROL_OFFSET);
/* return current value of the crashlog complete flag */
return !!(control & CRASHLOG_FLAG_TRIGGER_COMPLETE);
}
static bool pmt_crashlog_disabled(struct intel_pmt_entry *entry)
{
u32 control = readl(entry->disc_table + CONTROL_OFFSET);
/* return current value of the crashlog disabled flag */
return !!(control & CRASHLOG_FLAG_DISABLE);
}
static bool pmt_crashlog_supported(struct intel_pmt_entry *entry)
{
u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);
u32 crash_type, version;
crash_type = GET_TYPE(discovery_header);
version = GET_VERSION(discovery_header);
/*
* Currently we only recognize OOBMSM version 0 devices.
* We can ignore all other crashlog devices in the system.
*/
return crash_type == CRASH_TYPE_OOBMSM && version == 0;
}
static void pmt_crashlog_set_disable(struct intel_pmt_entry *entry,
bool disable)
{
u32 control = readl(entry->disc_table + CONTROL_OFFSET);
/* clear trigger bits so we are only modifying disable flag */
control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
if (disable)
control |= CRASHLOG_FLAG_DISABLE;
else
control &= ~CRASHLOG_FLAG_DISABLE;
writel(control, entry->disc_table + CONTROL_OFFSET);
}
static void pmt_crashlog_set_clear(struct intel_pmt_entry *entry)
{
u32 control = readl(entry->disc_table + CONTROL_OFFSET);
control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
control |= CRASHLOG_FLAG_TRIGGER_CLEAR;
writel(control, entry->disc_table + CONTROL_OFFSET);
}
static void pmt_crashlog_set_execute(struct intel_pmt_entry *entry)
{
u32 control = readl(entry->disc_table + CONTROL_OFFSET);
control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
control |= CRASHLOG_FLAG_TRIGGER_EXECUTE;
writel(control, entry->disc_table + CONTROL_OFFSET);
}
/*
* sysfs
*/
static ssize_t
enable_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct intel_pmt_entry *entry = dev_get_drvdata(dev);
int enabled = !pmt_crashlog_disabled(entry);
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 *entry;
bool enabled;
int result;
entry = dev_get_drvdata(dev);
result = kstrtobool(buf, &enabled);
if (result)
return result;
mutex_lock(&entry->control_mutex);
pmt_crashlog_set_disable(&entry->entry, !enabled);
mutex_unlock(&entry->control_mutex);
return count;
}
static DEVICE_ATTR_RW(enable);
static ssize_t
trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
{
struct intel_pmt_entry *entry;
int trigger;
entry = dev_get_drvdata(dev);
trigger = pmt_crashlog_complete(entry);
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 *entry;
bool trigger;
int result;
entry = dev_get_drvdata(dev);
result = kstrtobool(buf, &trigger);
if (result)
return result;
mutex_lock(&entry->control_mutex);
if (!trigger) {
pmt_crashlog_set_clear(&entry->entry);
} else if (pmt_crashlog_complete(&entry->entry)) {
/* we cannot trigger a new crash if one is still pending */
result = -EEXIST;
goto err;
} else if (pmt_crashlog_disabled(&entry->entry)) {
/* if device is currently disabled, return busy */
result = -EBUSY;
goto err;
} else {
pmt_crashlog_set_execute(&entry->entry);
}
result = count;
err:
mutex_unlock(&entry->control_mutex);
return result;
}
static DEVICE_ATTR_RW(trigger);
static struct attribute *pmt_crashlog_attrs[] = {
&dev_attr_enable.attr,
&dev_attr_trigger.attr,
NULL
};
static const struct attribute_group pmt_crashlog_group = {
.attrs = pmt_crashlog_attrs,
};
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;
if (!pmt_crashlog_supported(entry))
return 1;
/* initialize control mutex */
crashlog = container_of(entry, struct crashlog_entry, entry);
mutex_init(&crashlog->control_mutex);
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));
return 0;
}
static DEFINE_XARRAY_ALLOC(crashlog_array);
static struct intel_pmt_namespace pmt_crashlog_ns = {
.name = "crashlog",
.xa = &crashlog_array,
.attr_grp = &pmt_crashlog_group,
.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++)
intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
}
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 <[email protected]>");
MODULE_DESCRIPTION("Intel PMT Crashlog driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(INTEL_PMT);
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