xref: /openbmc/linux/drivers/char/tpm/tpm_atmel.c (revision b886d83c)
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 */
21 enum tpm_atmel_write_status {
22 	ATML_STATUS_ABORT = 0x01,
23 	ATML_STATUS_LASTBYTE = 0x04
24 };
25 /* read status bits */
26 enum 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 
tpm_atml_recv(struct tpm_chip * chip,u8 * buf,size_t count)33 static 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 
tpm_atml_send(struct tpm_chip * chip,u8 * buf,size_t count)92 static 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 
tpm_atml_cancel(struct tpm_chip * chip)106 static 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 
tpm_atml_status(struct tpm_chip * chip)113 static 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 
tpm_atml_req_canceled(struct tpm_chip * chip,u8 status)120 static bool tpm_atml_req_canceled(struct tpm_chip *chip, u8 status)
121 {
122 	return (status == ATML_STATUS_READY);
123 }
124 
125 static 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 
135 static struct platform_device *pdev;
136 
atml_plat_remove(void)137 static 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 
149 static SIMPLE_DEV_PM_OPS(tpm_atml_pm, tpm_pm_suspend, tpm_pm_resume);
150 
151 static struct platform_driver atml_drv = {
152 	.driver = {
153 		.name = "tpm_atmel",
154 		.pm		= &tpm_atml_pm,
155 	},
156 };
157 
init_atmel(void)158 static 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 
211 err_unreg_dev:
212 	platform_device_unregister(pdev);
213 err_rel_reg:
214 	atmel_put_base_addr(iobase);
215 	if (have_region)
216 		atmel_release_region(base,
217 				     region_size);
218 err_unreg_drv:
219 	platform_driver_unregister(&atml_drv);
220 	return rc;
221 }
222 
cleanup_atmel(void)223 static void __exit cleanup_atmel(void)
224 {
225 	platform_driver_unregister(&atml_drv);
226 	atml_plat_remove();
227 }
228 
229 module_init(init_atmel);
230 module_exit(cleanup_atmel);
231 
232 MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)");
233 MODULE_DESCRIPTION("TPM Driver");
234 MODULE_VERSION("2.0");
235 MODULE_LICENSE("GPL");
236