1/*
2 * Copyright (C) 2014 Intel Corporation
3 *
4 * Authors:
5 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
6 *
7 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
8 *
9 * This device driver implements the TPM interface as defined in
10 * the TCG CRB 2.0 TPM specification.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; version 2
15 * of the License.
16 */
17
18#include <linux/acpi.h>
19#include <linux/highmem.h>
20#include <linux/rculist.h>
21#include <linux/module.h>
22#include <linux/platform_device.h>
23#include "tpm.h"
24
25#define ACPI_SIG_TPM2 "TPM2"
26
27static const u8 CRB_ACPI_START_UUID[] = {
28	/* 0000 */ 0xAB, 0x6C, 0xBF, 0x6B, 0x63, 0x54, 0x14, 0x47,
29	/* 0008 */ 0xB7, 0xCD, 0xF0, 0x20, 0x3C, 0x03, 0x68, 0xD4
30};
31
32enum crb_defaults {
33	CRB_ACPI_START_REVISION_ID = 1,
34	CRB_ACPI_START_INDEX = 1,
35};
36
37struct acpi_tpm2 {
38	struct acpi_table_header hdr;
39	u16 platform_class;
40	u16 reserved;
41	u64 control_area_pa;
42	u32 start_method;
43} __packed;
44
45enum crb_ca_request {
46	CRB_CA_REQ_GO_IDLE	= BIT(0),
47	CRB_CA_REQ_CMD_READY	= BIT(1),
48};
49
50enum crb_ca_status {
51	CRB_CA_STS_ERROR	= BIT(0),
52	CRB_CA_STS_TPM_IDLE	= BIT(1),
53};
54
55enum crb_start {
56	CRB_START_INVOKE	= BIT(0),
57};
58
59enum crb_cancel {
60	CRB_CANCEL_INVOKE	= BIT(0),
61};
62
63struct crb_control_area {
64	u32 req;
65	u32 sts;
66	u32 cancel;
67	u32 start;
68	u32 int_enable;
69	u32 int_sts;
70	u32 cmd_size;
71	u64 cmd_pa;
72	u32 rsp_size;
73	u64 rsp_pa;
74} __packed;
75
76enum crb_status {
77	CRB_STS_COMPLETE	= BIT(0),
78};
79
80enum crb_flags {
81	CRB_FL_ACPI_START	= BIT(0),
82	CRB_FL_CRB_START	= BIT(1),
83};
84
85struct crb_priv {
86	unsigned int flags;
87	struct crb_control_area __iomem *cca;
88	u8 __iomem *cmd;
89	u8 __iomem *rsp;
90};
91
92static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
93
94static u8 crb_status(struct tpm_chip *chip)
95{
96	struct crb_priv *priv = chip->vendor.priv;
97	u8 sts = 0;
98
99	if ((le32_to_cpu(ioread32(&priv->cca->start)) & CRB_START_INVOKE) !=
100	    CRB_START_INVOKE)
101		sts |= CRB_STS_COMPLETE;
102
103	return sts;
104}
105
106static int crb_recv(struct tpm_chip *chip, u8 *buf, size_t count)
107{
108	struct crb_priv *priv = chip->vendor.priv;
109	unsigned int expected;
110
111	/* sanity check */
112	if (count < 6)
113		return -EIO;
114
115	if (le32_to_cpu(ioread32(&priv->cca->sts)) & CRB_CA_STS_ERROR)
116		return -EIO;
117
118	memcpy_fromio(buf, priv->rsp, 6);
119	expected = be32_to_cpup((__be32 *) &buf[2]);
120
121	if (expected > count)
122		return -EIO;
123
124	memcpy_fromio(&buf[6], &priv->rsp[6], expected - 6);
125
126	return expected;
127}
128
129static int crb_do_acpi_start(struct tpm_chip *chip)
130{
131	union acpi_object *obj;
132	int rc;
133
134	obj = acpi_evaluate_dsm(chip->acpi_dev_handle,
135				CRB_ACPI_START_UUID,
136				CRB_ACPI_START_REVISION_ID,
137				CRB_ACPI_START_INDEX,
138				NULL);
139	if (!obj)
140		return -ENXIO;
141	rc = obj->integer.value == 0 ? 0 : -ENXIO;
142	ACPI_FREE(obj);
143	return rc;
144}
145
146static int crb_send(struct tpm_chip *chip, u8 *buf, size_t len)
147{
148	struct crb_priv *priv = chip->vendor.priv;
149	int rc = 0;
150
151	if (len > le32_to_cpu(ioread32(&priv->cca->cmd_size))) {
152		dev_err(&chip->dev,
153			"invalid command count value %x %zx\n",
154			(unsigned int) len,
155			(size_t) le32_to_cpu(ioread32(&priv->cca->cmd_size)));
156		return -E2BIG;
157	}
158
159	memcpy_toio(priv->cmd, buf, len);
160
161	/* Make sure that cmd is populated before issuing start. */
162	wmb();
163
164	if (priv->flags & CRB_FL_CRB_START)
165		iowrite32(cpu_to_le32(CRB_START_INVOKE), &priv->cca->start);
166
167	if (priv->flags & CRB_FL_ACPI_START)
168		rc = crb_do_acpi_start(chip);
169
170	return rc;
171}
172
173static void crb_cancel(struct tpm_chip *chip)
174{
175	struct crb_priv *priv = chip->vendor.priv;
176
177	iowrite32(cpu_to_le32(CRB_CANCEL_INVOKE), &priv->cca->cancel);
178
179	/* Make sure that cmd is populated before issuing cancel. */
180	wmb();
181
182	if ((priv->flags & CRB_FL_ACPI_START) && crb_do_acpi_start(chip))
183		dev_err(&chip->dev, "ACPI Start failed\n");
184
185	iowrite32(0, &priv->cca->cancel);
186}
187
188static bool crb_req_canceled(struct tpm_chip *chip, u8 status)
189{
190	struct crb_priv *priv = chip->vendor.priv;
191	u32 cancel = le32_to_cpu(ioread32(&priv->cca->cancel));
192
193	return (cancel & CRB_CANCEL_INVOKE) == CRB_CANCEL_INVOKE;
194}
195
196static const struct tpm_class_ops tpm_crb = {
197	.status = crb_status,
198	.recv = crb_recv,
199	.send = crb_send,
200	.cancel = crb_cancel,
201	.req_canceled = crb_req_canceled,
202	.req_complete_mask = CRB_STS_COMPLETE,
203	.req_complete_val = CRB_STS_COMPLETE,
204};
205
206static int crb_acpi_add(struct acpi_device *device)
207{
208	struct tpm_chip *chip;
209	struct acpi_tpm2 *buf;
210	struct crb_priv *priv;
211	struct device *dev = &device->dev;
212	acpi_status status;
213	u32 sm;
214	u64 pa;
215	int rc;
216
217	status = acpi_get_table(ACPI_SIG_TPM2, 1,
218				(struct acpi_table_header **) &buf);
219	if (ACPI_FAILURE(status)) {
220		dev_err(dev, "failed to get TPM2 ACPI table\n");
221		return -ENODEV;
222	}
223
224	/* Should the FIFO driver handle this? */
225	if (buf->start_method == TPM2_START_FIFO)
226		return -ENODEV;
227
228	chip = tpmm_chip_alloc(dev, &tpm_crb);
229	if (IS_ERR(chip))
230		return PTR_ERR(chip);
231
232	chip->flags = TPM_CHIP_FLAG_TPM2;
233
234	if (buf->hdr.length < sizeof(struct acpi_tpm2)) {
235		dev_err(dev, "TPM2 ACPI table has wrong size");
236		return -EINVAL;
237	}
238
239	priv = (struct crb_priv *) devm_kzalloc(dev, sizeof(struct crb_priv),
240						GFP_KERNEL);
241	if (!priv) {
242		dev_err(dev, "failed to devm_kzalloc for private data\n");
243		return -ENOMEM;
244	}
245
246	sm = le32_to_cpu(buf->start_method);
247
248	/* The reason for the extra quirk is that the PTT in 4th Gen Core CPUs
249	 * report only ACPI start but in practice seems to require both
250	 * ACPI start and CRB start.
251	 */
252	if (sm == TPM2_START_CRB || sm == TPM2_START_FIFO ||
253	    !strcmp(acpi_device_hid(device), "MSFT0101"))
254		priv->flags |= CRB_FL_CRB_START;
255
256	if (sm == TPM2_START_ACPI || sm == TPM2_START_CRB_WITH_ACPI)
257		priv->flags |= CRB_FL_ACPI_START;
258
259	priv->cca = (struct crb_control_area __iomem *)
260		devm_ioremap_nocache(dev, buf->control_area_pa, 0x1000);
261	if (!priv->cca) {
262		dev_err(dev, "ioremap of the control area failed\n");
263		return -ENOMEM;
264	}
265
266	memcpy_fromio(&pa, &priv->cca->cmd_pa, 8);
267	pa = le64_to_cpu(pa);
268	priv->cmd = devm_ioremap_nocache(dev, pa,
269					 ioread32(&priv->cca->cmd_size));
270	if (!priv->cmd) {
271		dev_err(dev, "ioremap of the command buffer failed\n");
272		return -ENOMEM;
273	}
274
275	memcpy_fromio(&pa, &priv->cca->rsp_pa, 8);
276	pa = le64_to_cpu(pa);
277	priv->rsp = devm_ioremap_nocache(dev, pa,
278					 ioread32(&priv->cca->rsp_size));
279	if (!priv->rsp) {
280		dev_err(dev, "ioremap of the response buffer failed\n");
281		return -ENOMEM;
282	}
283
284	chip->vendor.priv = priv;
285
286	/* Default timeouts and durations */
287	chip->vendor.timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
288	chip->vendor.timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
289	chip->vendor.timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
290	chip->vendor.timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);
291	chip->vendor.duration[TPM_SHORT] =
292		msecs_to_jiffies(TPM2_DURATION_SHORT);
293	chip->vendor.duration[TPM_MEDIUM] =
294		msecs_to_jiffies(TPM2_DURATION_MEDIUM);
295	chip->vendor.duration[TPM_LONG] =
296		msecs_to_jiffies(TPM2_DURATION_LONG);
297
298	chip->acpi_dev_handle = device->handle;
299
300	rc = tpm2_do_selftest(chip);
301	if (rc)
302		return rc;
303
304	return tpm_chip_register(chip);
305}
306
307static int crb_acpi_remove(struct acpi_device *device)
308{
309	struct device *dev = &device->dev;
310	struct tpm_chip *chip = dev_get_drvdata(dev);
311
312	if (chip->flags & TPM_CHIP_FLAG_TPM2)
313		tpm2_shutdown(chip, TPM2_SU_CLEAR);
314
315	tpm_chip_unregister(chip);
316
317	return 0;
318}
319
320static struct acpi_device_id crb_device_ids[] = {
321	{"MSFT0101", 0},
322	{"", 0},
323};
324MODULE_DEVICE_TABLE(acpi, crb_device_ids);
325
326static struct acpi_driver crb_acpi_driver = {
327	.name = "tpm_crb",
328	.ids = crb_device_ids,
329	.ops = {
330		.add = crb_acpi_add,
331		.remove = crb_acpi_remove,
332	},
333	.drv = {
334		.pm = &crb_pm,
335	},
336};
337
338module_acpi_driver(crb_acpi_driver);
339MODULE_AUTHOR("Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>");
340MODULE_DESCRIPTION("TPM2 Driver");
341MODULE_VERSION("0.1");
342MODULE_LICENSE("GPL");
343