1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Intel Platform Monitoring Technology Crashlog driver
  4 *
  5 * Copyright (c) 2020, Intel Corporation.
  6 * All Rights Reserved.
  7 *
  8 * Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
  9 */
 10
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/pci.h>
 14#include <linux/slab.h>
 15#include <linux/uaccess.h>
 16#include <linux/overflow.h>
 17
 18#include "intel_pmt_class.h"
 19
 20#define DRV_NAME		"pmt_crashlog"
 21
 22/* Crashlog discovery header types */
 23#define CRASH_TYPE_OOBMSM	1
 24
 25/* Control Flags */
 26#define CRASHLOG_FLAG_DISABLE		BIT(28)
 27
 28/*
 29 * Bits 29 and 30 control the state of bit 31.
 30 *
 31 * Bit 29 will clear bit 31, if set, allowing a new crashlog to be captured.
 32 * Bit 30 will immediately trigger a crashlog to be generated, setting bit 31.
 33 * Bit 31 is the read-only status with a 1 indicating log is complete.
 34 */
 35#define CRASHLOG_FLAG_TRIGGER_CLEAR	BIT(29)
 36#define CRASHLOG_FLAG_TRIGGER_EXECUTE	BIT(30)
 37#define CRASHLOG_FLAG_TRIGGER_COMPLETE	BIT(31)
 38#define CRASHLOG_FLAG_TRIGGER_MASK	GENMASK(31, 28)
 39
 40/* Crashlog Discovery Header */
 41#define CONTROL_OFFSET		0x0
 42#define GUID_OFFSET		0x4
 43#define BASE_OFFSET		0x8
 44#define SIZE_OFFSET		0xC
 45#define GET_ACCESS(v)		((v) & GENMASK(3, 0))
 46#define GET_TYPE(v)		(((v) & GENMASK(7, 4)) >> 4)
 47#define GET_VERSION(v)		(((v) & GENMASK(19, 16)) >> 16)
 48/* size is in bytes */
 49#define GET_SIZE(v)		((v) * sizeof(u32))
 50
 51struct crashlog_entry {
 52	/* entry must be first member of struct */
 53	struct intel_pmt_entry		entry;
 54	struct mutex			control_mutex;
 55};
 56
 57struct pmt_crashlog_priv {
 58	int			num_entries;
 59	struct crashlog_entry	entry[];
 60};
 61
 62/*
 63 * I/O
 64 */
 65static bool pmt_crashlog_complete(struct intel_pmt_entry *entry)
 66{
 67	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
 68
 69	/* return current value of the crashlog complete flag */
 70	return !!(control & CRASHLOG_FLAG_TRIGGER_COMPLETE);
 71}
 72
 73static bool pmt_crashlog_disabled(struct intel_pmt_entry *entry)
 74{
 75	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
 76
 77	/* return current value of the crashlog disabled flag */
 78	return !!(control & CRASHLOG_FLAG_DISABLE);
 79}
 80
 81static bool pmt_crashlog_supported(struct intel_pmt_entry *entry)
 82{
 83	u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);
 84	u32 crash_type, version;
 85
 86	crash_type = GET_TYPE(discovery_header);
 87	version = GET_VERSION(discovery_header);
 88
 89	/*
 90	 * Currently we only recognize OOBMSM version 0 devices.
 91	 * We can ignore all other crashlog devices in the system.
 92	 */
 93	return crash_type == CRASH_TYPE_OOBMSM && version == 0;
 94}
 95
 96static void pmt_crashlog_set_disable(struct intel_pmt_entry *entry,
 97				     bool disable)
 98{
 99	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
100
101	/* clear trigger bits so we are only modifying disable flag */
102	control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
103
104	if (disable)
105		control |= CRASHLOG_FLAG_DISABLE;
106	else
107		control &= ~CRASHLOG_FLAG_DISABLE;
108
109	writel(control, entry->disc_table + CONTROL_OFFSET);
110}
111
112static void pmt_crashlog_set_clear(struct intel_pmt_entry *entry)
113{
114	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
115
116	control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
117	control |= CRASHLOG_FLAG_TRIGGER_CLEAR;
118
119	writel(control, entry->disc_table + CONTROL_OFFSET);
120}
121
122static void pmt_crashlog_set_execute(struct intel_pmt_entry *entry)
123{
124	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
125
126	control &= ~CRASHLOG_FLAG_TRIGGER_MASK;
127	control |= CRASHLOG_FLAG_TRIGGER_EXECUTE;
128
129	writel(control, entry->disc_table + CONTROL_OFFSET);
130}
131
132/*
133 * sysfs
134 */
135static ssize_t
136enable_show(struct device *dev, struct device_attribute *attr, char *buf)
137{
138	struct intel_pmt_entry *entry = dev_get_drvdata(dev);
139	int enabled = !pmt_crashlog_disabled(entry);
140
141	return sprintf(buf, "%d\n", enabled);
142}
143
144static ssize_t
145enable_store(struct device *dev, struct device_attribute *attr,
146	    const char *buf, size_t count)
147{
148	struct crashlog_entry *entry;
149	bool enabled;
150	int result;
151
152	entry = dev_get_drvdata(dev);
153
154	result = kstrtobool(buf, &enabled);
155	if (result)
156		return result;
157
158	mutex_lock(&entry->control_mutex);
159	pmt_crashlog_set_disable(&entry->entry, !enabled);
160	mutex_unlock(&entry->control_mutex);
161
162	return count;
163}
164static DEVICE_ATTR_RW(enable);
165
166static ssize_t
167trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
168{
169	struct intel_pmt_entry *entry;
170	int trigger;
171
172	entry = dev_get_drvdata(dev);
173	trigger = pmt_crashlog_complete(entry);
174
175	return sprintf(buf, "%d\n", trigger);
176}
177
178static ssize_t
179trigger_store(struct device *dev, struct device_attribute *attr,
180	    const char *buf, size_t count)
181{
182	struct crashlog_entry *entry;
183	bool trigger;
184	int result;
185
186	entry = dev_get_drvdata(dev);
187
188	result = kstrtobool(buf, &trigger);
189	if (result)
190		return result;
191
192	mutex_lock(&entry->control_mutex);
193
194	if (!trigger) {
195		pmt_crashlog_set_clear(&entry->entry);
196	} else if (pmt_crashlog_complete(&entry->entry)) {
197		/* we cannot trigger a new crash if one is still pending */
198		result = -EEXIST;
199		goto err;
200	} else if (pmt_crashlog_disabled(&entry->entry)) {
201		/* if device is currently disabled, return busy */
202		result = -EBUSY;
203		goto err;
204	} else {
205		pmt_crashlog_set_execute(&entry->entry);
206	}
207
208	result = count;
209err:
210	mutex_unlock(&entry->control_mutex);
211	return result;
212}
213static DEVICE_ATTR_RW(trigger);
214
215static struct attribute *pmt_crashlog_attrs[] = {
216	&dev_attr_enable.attr,
217	&dev_attr_trigger.attr,
218	NULL
219};
220
221static const struct attribute_group pmt_crashlog_group = {
222	.attrs	= pmt_crashlog_attrs,
223};
224
225static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
226				      struct intel_pmt_header *header,
227				      struct device *dev)
228{
229	void __iomem *disc_table = entry->disc_table;
230	struct crashlog_entry *crashlog;
231
232	if (!pmt_crashlog_supported(entry))
233		return 1;
234
235	/* initialize control mutex */
236	crashlog = container_of(entry, struct crashlog_entry, entry);
237	mutex_init(&crashlog->control_mutex);
238
239	header->access_type = GET_ACCESS(readl(disc_table));
240	header->guid = readl(disc_table + GUID_OFFSET);
241	header->base_offset = readl(disc_table + BASE_OFFSET);
242
243	/* Size is measured in DWORDS, but accessor returns bytes */
244	header->size = GET_SIZE(readl(disc_table + SIZE_OFFSET));
245
246	return 0;
247}
248
249static DEFINE_XARRAY_ALLOC(crashlog_array);
250static struct intel_pmt_namespace pmt_crashlog_ns = {
251	.name = "crashlog",
252	.xa = &crashlog_array,
253	.attr_grp = &pmt_crashlog_group,
254	.pmt_header_decode = pmt_crashlog_header_decode,
255};
256
257/*
258 * initialization
259 */
260static int pmt_crashlog_remove(struct platform_device *pdev)
261{
262	struct pmt_crashlog_priv *priv = platform_get_drvdata(pdev);
263	int i;
264
265	for (i = 0; i < priv->num_entries; i++)
266		intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
267
268	return 0;
269}
270
271static int pmt_crashlog_probe(struct platform_device *pdev)
272{
273	struct pmt_crashlog_priv *priv;
274	size_t size;
275	int i, ret;
276
277	size = struct_size(priv, entry, pdev->num_resources);
278	priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
279	if (!priv)
280		return -ENOMEM;
281
282	platform_set_drvdata(pdev, priv);
283
284	for (i = 0; i < pdev->num_resources; i++) {
285		struct intel_pmt_entry *entry = &priv->entry[i].entry;
286
287		ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, pdev, i);
288		if (ret < 0)
289			goto abort_probe;
290		if (ret)
291			continue;
292
293		priv->num_entries++;
294	}
295
296	return 0;
297abort_probe:
298	pmt_crashlog_remove(pdev);
299	return ret;
300}
301
302static struct platform_driver pmt_crashlog_driver = {
303	.driver = {
304		.name   = DRV_NAME,
305	},
306	.remove = pmt_crashlog_remove,
307	.probe  = pmt_crashlog_probe,
308};
309
310static int __init pmt_crashlog_init(void)
311{
312	return platform_driver_register(&pmt_crashlog_driver);
313}
314
315static void __exit pmt_crashlog_exit(void)
316{
317	platform_driver_unregister(&pmt_crashlog_driver);
318	xa_destroy(&crashlog_array);
319}
320
321module_init(pmt_crashlog_init);
322module_exit(pmt_crashlog_exit);
323
324MODULE_AUTHOR("Alexander Duyck <alexander.h.duyck@linux.intel.com>");
325MODULE_DESCRIPTION("Intel PMT Crashlog driver");
326MODULE_ALIAS("platform:" DRV_NAME);
327MODULE_LICENSE("GPL v2");