1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) Microsoft Corporation
5 * Implements a firmware TPM as described here:
6 * https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/
8 * A reference implementation is available here:
9 * https://github.com/microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM
12 #include <linux/acpi.h>
14 #include <linux/of_platform.h>
15 #include <linux/platform_device.h>
16 #include <linux/tee_drv.h>
17 #include <linux/tpm.h>
18 #include <linux/uuid.h>
21 #include "tpm_ftpm_tee.h"
24 * TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896
26 * Randomly generated, and must correspond to the GUID on the TA side.
27 * Defined here in the reference implementation:
28 * https://github.com/microsoft/ms-tpm-20-ref/blob/master/Samples/ARM32-FirmwareTPM/optee_ta/fTPM/include/fTPM.h#L42
30 static const uuid_t ftpm_ta_uuid =
31 UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4,
32 0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96);
35 * ftpm_tee_tpm_op_recv - retrieve fTPM response.
36 * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h.
37 * @buf: the buffer to store data.
38 * @count: the number of bytes to read.
41 * In case of success the number of bytes received.
44 static int ftpm_tee_tpm_op_recv(struct tpm_chip *chip, u8 *buf, size_t count)
46 struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
49 len = pvt_data->resp_len;
52 "%s: Invalid size in recv: count=%zd, resp_len=%zd\n",
53 __func__, count, len);
57 memcpy(buf, pvt_data->resp_buf, len);
58 pvt_data->resp_len = 0;
64 * ftpm_tee_tpm_op_send - send TPM commands through the TEE shared memory.
65 * @chip: the tpm_chip description as specified in driver/char/tpm/tpm.h
66 * @buf: the buffer to send.
67 * @len: the number of bytes to send.
70 * In case of success, returns 0.
73 static int ftpm_tee_tpm_op_send(struct tpm_chip *chip, u8 *buf, size_t len)
75 struct ftpm_tee_private *pvt_data = dev_get_drvdata(chip->dev.parent);
79 struct tpm_header *resp_header;
80 struct tee_ioctl_invoke_arg transceive_args;
81 struct tee_param command_params[4];
82 struct tee_shm *shm = pvt_data->shm;
84 if (len > MAX_COMMAND_SIZE) {
86 "%s: len=%zd exceeds MAX_COMMAND_SIZE supported by fTPM TA\n",
91 memset(&transceive_args, 0, sizeof(transceive_args));
92 memset(command_params, 0, sizeof(command_params));
93 pvt_data->resp_len = 0;
95 /* Invoke FTPM_OPTEE_TA_SUBMIT_COMMAND function of fTPM TA */
96 transceive_args = (struct tee_ioctl_invoke_arg) {
97 .func = FTPM_OPTEE_TA_SUBMIT_COMMAND,
98 .session = pvt_data->session,
102 /* Fill FTPM_OPTEE_TA_SUBMIT_COMMAND parameters */
103 command_params[0] = (struct tee_param) {
104 .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
112 temp_buf = tee_shm_get_va(shm, 0);
113 if (IS_ERR(temp_buf)) {
114 dev_err(&chip->dev, "%s: tee_shm_get_va failed for transmit\n",
116 return PTR_ERR(temp_buf);
118 memset(temp_buf, 0, (MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE));
119 memcpy(temp_buf, buf, len);
121 command_params[1] = (struct tee_param) {
122 .attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT,
125 .size = MAX_RESPONSE_SIZE,
126 .shm_offs = MAX_COMMAND_SIZE,
130 rc = tee_client_invoke_func(pvt_data->ctx, &transceive_args,
132 if ((rc < 0) || (transceive_args.ret != 0)) {
133 dev_err(&chip->dev, "%s: SUBMIT_COMMAND invoke error: 0x%x\n",
134 __func__, transceive_args.ret);
135 return (rc < 0) ? rc : transceive_args.ret;
138 temp_buf = tee_shm_get_va(shm, command_params[1].u.memref.shm_offs);
139 if (IS_ERR(temp_buf)) {
140 dev_err(&chip->dev, "%s: tee_shm_get_va failed for receive\n",
142 return PTR_ERR(temp_buf);
145 resp_header = (struct tpm_header *)temp_buf;
146 resp_len = be32_to_cpu(resp_header->length);
148 /* sanity check resp_len */
149 if (resp_len < TPM_HEADER_SIZE) {
150 dev_err(&chip->dev, "%s: tpm response header too small\n",
154 if (resp_len > MAX_RESPONSE_SIZE) {
156 "%s: resp_len=%zd exceeds MAX_RESPONSE_SIZE\n",
161 /* sanity checks look good, cache the response */
162 memcpy(pvt_data->resp_buf, temp_buf, resp_len);
163 pvt_data->resp_len = resp_len;
168 static void ftpm_tee_tpm_op_cancel(struct tpm_chip *chip)
173 static u8 ftpm_tee_tpm_op_status(struct tpm_chip *chip)
178 static bool ftpm_tee_tpm_req_canceled(struct tpm_chip *chip, u8 status)
183 static const struct tpm_class_ops ftpm_tee_tpm_ops = {
184 .flags = TPM_OPS_AUTO_STARTUP,
185 .recv = ftpm_tee_tpm_op_recv,
186 .send = ftpm_tee_tpm_op_send,
187 .cancel = ftpm_tee_tpm_op_cancel,
188 .status = ftpm_tee_tpm_op_status,
189 .req_complete_mask = 0,
190 .req_complete_val = 0,
191 .req_canceled = ftpm_tee_tpm_req_canceled,
195 * Check whether this driver supports the fTPM TA in the TEE instance
196 * represented by the params (ver/data) to this function.
198 static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data)
201 * Currently this driver only support GP Complaint OPTEE based fTPM TA
203 if ((ver->impl_id == TEE_IMPL_ID_OPTEE) &&
204 (ver->gen_caps & TEE_GEN_CAP_GP))
211 * ftpm_tee_probe - initialize the fTPM
212 * @pdev: the platform_device description.
215 * On success, 0. On failure, -errno.
217 static int ftpm_tee_probe(struct platform_device *pdev)
220 struct tpm_chip *chip;
221 struct device *dev = &pdev->dev;
222 struct ftpm_tee_private *pvt_data = NULL;
223 struct tee_ioctl_open_session_arg sess_arg;
225 pvt_data = devm_kzalloc(dev, sizeof(struct ftpm_tee_private),
230 dev_set_drvdata(dev, pvt_data);
232 /* Open context with TEE driver */
233 pvt_data->ctx = tee_client_open_context(NULL, ftpm_tee_match, NULL,
235 if (IS_ERR(pvt_data->ctx)) {
236 if (PTR_ERR(pvt_data->ctx) == -ENOENT)
237 return -EPROBE_DEFER;
238 dev_err(dev, "%s: tee_client_open_context failed\n", __func__);
239 return PTR_ERR(pvt_data->ctx);
242 /* Open a session with fTPM TA */
243 memset(&sess_arg, 0, sizeof(sess_arg));
244 memcpy(sess_arg.uuid, ftpm_ta_uuid.b, TEE_IOCTL_UUID_LEN);
245 sess_arg.clnt_login = TEE_IOCTL_LOGIN_PUBLIC;
246 sess_arg.num_params = 0;
248 rc = tee_client_open_session(pvt_data->ctx, &sess_arg, NULL);
249 if ((rc < 0) || (sess_arg.ret != 0)) {
250 dev_err(dev, "%s: tee_client_open_session failed, err=%x\n",
251 __func__, sess_arg.ret);
253 goto out_tee_session;
255 pvt_data->session = sess_arg.session;
257 /* Allocate dynamic shared memory with fTPM TA */
258 pvt_data->shm = tee_shm_alloc(pvt_data->ctx,
259 MAX_COMMAND_SIZE + MAX_RESPONSE_SIZE,
260 TEE_SHM_MAPPED | TEE_SHM_DMA_BUF);
261 if (IS_ERR(pvt_data->shm)) {
262 dev_err(dev, "%s: tee_shm_alloc failed\n", __func__);
267 /* Allocate new struct tpm_chip instance */
268 chip = tpm_chip_alloc(dev, &ftpm_tee_tpm_ops);
270 dev_err(dev, "%s: tpm_chip_alloc failed\n", __func__);
275 pvt_data->chip = chip;
276 pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2;
278 /* Create a character device for the fTPM */
279 rc = tpm_chip_register(pvt_data->chip);
281 dev_err(dev, "%s: tpm_chip_register failed with rc=%d\n",
289 put_device(&pvt_data->chip->dev);
291 tee_shm_free(pvt_data->shm);
293 tee_client_close_session(pvt_data->ctx, pvt_data->session);
295 tee_client_close_context(pvt_data->ctx);
301 * ftpm_tee_remove - remove the TPM device
302 * @pdev: the platform_device description.
307 static int ftpm_tee_remove(struct platform_device *pdev)
309 struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
311 /* Release the chip */
312 tpm_chip_unregister(pvt_data->chip);
315 put_device(&pvt_data->chip->dev);
317 /* Free the shared memory pool */
318 tee_shm_free(pvt_data->shm);
320 /* close the existing session with fTPM TA*/
321 tee_client_close_session(pvt_data->ctx, pvt_data->session);
323 /* close the context with TEE driver */
324 tee_client_close_context(pvt_data->ctx);
326 /* memory allocated with devm_kzalloc() is freed automatically */
331 static const struct of_device_id of_ftpm_tee_ids[] = {
332 { .compatible = "microsoft,ftpm" },
335 MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids);
337 static struct platform_driver ftpm_tee_driver = {
340 .of_match_table = of_match_ptr(of_ftpm_tee_ids),
342 .probe = ftpm_tee_probe,
343 .remove = ftpm_tee_remove,
346 module_platform_driver(ftpm_tee_driver);
348 MODULE_AUTHOR("Thirupathaiah Annapureddy <thiruan@microsoft.com>");
349 MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE");
350 MODULE_LICENSE("GPL v2");