1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2004 IBM Corporation
4 *
5 * Authors:
6 * Leendert van Doorn <leendert@watson.ibm.com>
7 * Dave Safford <safford@watson.ibm.com>
8 * Reiner Sailer <sailer@watson.ibm.com>
9 * Kylene Hall <kjhall@us.ibm.com>
10 *
11 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
12 *
13 * Device driver for TCG/TCPA TPM (trusted platform module).
14 * Specifications at www.trustedcomputinggroup.org
15 */
16
17#include "tpm.h"
18#include "tpm_atmel.h"
19
20/* write status bits */
21enum tpm_atmel_write_status {
22	ATML_STATUS_ABORT = 0x01,
23	ATML_STATUS_LASTBYTE = 0x04
24};
25/* read status bits */
26enum tpm_atmel_read_status {
27	ATML_STATUS_BUSY = 0x01,
28	ATML_STATUS_DATA_AVAIL = 0x02,
29	ATML_STATUS_REWRITE = 0x04,
30	ATML_STATUS_READY = 0x08
31};
32
33static int tpm_atml_recv(struct tpm_chip *chip, u8 *buf, size_t count)
34{
35	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
36	u8 status, *hdr = buf;
37	u32 size;
38	int i;
39	__be32 *native_size;
40
41	/* start reading header */
42	if (count < 6)
43		return -EIO;
44
45	for (i = 0; i < 6; i++) {
46		status = ioread8(priv->iobase + 1);
47		if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
48			dev_err(&chip->dev, "error reading header\n");
49			return -EIO;
50		}
51		*buf++ = ioread8(priv->iobase);
52	}
53
54	/* size of the data received */
55	native_size = (__force __be32 *) (hdr + 2);
56	size = be32_to_cpu(*native_size);
57
58	if (count < size) {
59		dev_err(&chip->dev,
60			"Recv size(%d) less than available space\n", size);
61		for (; i < size; i++) {	/* clear the waiting data anyway */
62			status = ioread8(priv->iobase + 1);
63			if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
64				dev_err(&chip->dev, "error reading data\n");
65				return -EIO;
66			}
67		}
68		return -EIO;
69	}
70
71	/* read all the data available */
72	for (; i < size; i++) {
73		status = ioread8(priv->iobase + 1);
74		if ((status & ATML_STATUS_DATA_AVAIL) == 0) {
75			dev_err(&chip->dev, "error reading data\n");
76			return -EIO;
77		}
78		*buf++ = ioread8(priv->iobase);
79	}
80
81	/* make sure data available is gone */
82	status = ioread8(priv->iobase + 1);
83
84	if (status & ATML_STATUS_DATA_AVAIL) {
85		dev_err(&chip->dev, "data available is stuck\n");
86		return -EIO;
87	}
88
89	return size;
90}
91
92static int tpm_atml_send(struct tpm_chip *chip, u8 *buf, size_t count)
93{
94	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
95	int i;
96
97	dev_dbg(&chip->dev, "tpm_atml_send:\n");
98	for (i = 0; i < count; i++) {
99		dev_dbg(&chip->dev, "%d 0x%x(%d)\n",  i, buf[i], buf[i]);
100		iowrite8(buf[i], priv->iobase);
101	}
102
103	return 0;
104}
105
106static void tpm_atml_cancel(struct tpm_chip *chip)
107{
108	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
109
110	iowrite8(ATML_STATUS_ABORT, priv->iobase + 1);
111}
112
113static u8 tpm_atml_status(struct tpm_chip *chip)
114{
115	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
116
117	return ioread8(priv->iobase + 1);
118}
119
120static bool tpm_atml_req_canceled(struct tpm_chip *chip, u8 status)
121{
122	return (status == ATML_STATUS_READY);
123}
124
125static const struct tpm_class_ops tpm_atmel = {
126	.recv = tpm_atml_recv,
127	.send = tpm_atml_send,
128	.cancel = tpm_atml_cancel,
129	.status = tpm_atml_status,
130	.req_complete_mask = ATML_STATUS_BUSY | ATML_STATUS_DATA_AVAIL,
131	.req_complete_val = ATML_STATUS_DATA_AVAIL,
132	.req_canceled = tpm_atml_req_canceled,
133};
134
135static struct platform_device *pdev;
136
137static void atml_plat_remove(void)
138{
139	struct tpm_chip *chip = dev_get_drvdata(&pdev->dev);
140	struct tpm_atmel_priv *priv = dev_get_drvdata(&chip->dev);
141
142	tpm_chip_unregister(chip);
143	if (priv->have_region)
144		atmel_release_region(priv->base, priv->region_size);
145	atmel_put_base_addr(priv->iobase);
146	platform_device_unregister(pdev);
147}
148
149static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);
150
151static struct platform_driver atml_drv = {
152	.driver = {
153		.name = "tpm_atmel",
154		.pm		= &tpm_atml_pm,
155	},
156};
157
158static int __init init_atmel(void)
159{
160	int rc = 0;
161	void __iomem *iobase = NULL;
162	int have_region, region_size;
163	unsigned long base;
164	struct  tpm_chip *chip;
165	struct tpm_atmel_priv *priv;
166
167	rc = platform_driver_register(&atml_drv);
168	if (rc)
169		return rc;
170
171	if ((iobase = atmel_get_base_addr(&base, &region_size)) == NULL) {
172		rc = -ENODEV;
173		goto err_unreg_drv;
174	}
175
176	have_region =
177	    (atmel_request_region
178	     (base, region_size, "tpm_atmel0") == NULL) ? 0 : 1;
179
180	pdev = platform_device_register_simple("tpm_atmel", -1, NULL, 0);
181	if (IS_ERR(pdev)) {
182		rc = PTR_ERR(pdev);
183		goto err_rel_reg;
184	}
185
186	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
187	if (!priv) {
188		rc = -ENOMEM;
189		goto err_unreg_dev;
190	}
191
192	priv->iobase = iobase;
193	priv->base = base;
194	priv->have_region = have_region;
195	priv->region_size = region_size;
196
197	chip = tpmm_chip_alloc(&pdev->dev, &tpm_atmel);
198	if (IS_ERR(chip)) {
199		rc = PTR_ERR(chip);
200		goto err_unreg_dev;
201	}
202
203	dev_set_drvdata(&chip->dev, priv);
204
205	rc = tpm_chip_register(chip);
206	if (rc)
207		goto err_unreg_dev;
208
209	return 0;
210
211err_unreg_dev:
212	platform_device_unregister(pdev);
213err_rel_reg:
214	atmel_put_base_addr(iobase);
215	if (have_region)
216		atmel_release_region(base,
217				     region_size);
218err_unreg_drv:
219	platform_driver_unregister(&atml_drv);
220	return rc;
221}
222
223static void __exit cleanup_atmel(void)
224{
225	platform_driver_unregister(&atml_drv);
226	atml_plat_remove();
227}
228
229module_init(init_atmel);
230module_exit(cleanup_atmel);
231
232MODULE_AUTHOR("Leendert van Doorn <leendert@watson.ibm.com>");
233MODULE_DESCRIPTION("TPM Driver");
234MODULE_VERSION("2.0");
235MODULE_LICENSE("GPL");
236