drivers/firmware/qcom/qcom_qseecom.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for Qualcomm Secure Execution Environment (SEE) interface (QSEECOM).
   4  * Responsible for setting up and managing QSEECOM client devices.
   5  *
   6  * Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
   7  */
   8 #include <linux/auxiliary_bus.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/slab.h>
  12 #include <linux/types.h>
  13
  14 #include <linux/firmware/qcom/qcom_qseecom.h>
  15 #include <linux/firmware/qcom/qcom_scm.h>
  16
  17 struct qseecom_app_desc {
  18         const char *app_name;
  19         const char *dev_name;
  20 };
  21
  22 static void qseecom_client_release(struct device *dev)
  23 {
  24         struct qseecom_client *client;
  25
  26         client = container_of(dev, struct qseecom_client, aux_dev.dev);
  27         kfree(client);
  28 }
  29
  30 static void qseecom_client_remove(void *data)
  31 {
  32         struct qseecom_client *client = data;
  33
  34         auxiliary_device_delete(&client->aux_dev);
  35         auxiliary_device_uninit(&client->aux_dev);
  36 }
  37
  38 static int qseecom_client_register(struct platform_device *qseecom_dev,
  39                                    const struct qseecom_app_desc *desc)
  40 {
  41         struct qseecom_client *client;
  42         u32 app_id;
  43         int ret;
  44
  45         /* Try to find the app ID, skip device if not found */
  46         ret = qcom_scm_qseecom_app_get_id(desc->app_name, &app_id);
  47         if (ret)
  48                 return ret == -ENOENT ? 0 : ret;
  49
  50         dev_info(&qseecom_dev->dev, "setting up client for %s\n", desc->app_name);
  51
  52         /* Allocate and set-up the client device */
  53         client = kzalloc(sizeof(*client), GFP_KERNEL);
  54         if (!client)
  55                 return -ENOMEM;
  56
  57         client->aux_dev.name = desc->dev_name;
  58         client->aux_dev.dev.parent = &qseecom_dev->dev;
  59         client->aux_dev.dev.release = qseecom_client_release;
  60         client->app_id = app_id;
  61
  62         ret = auxiliary_device_init(&client->aux_dev);
  63         if (ret) {
  64                 kfree(client);
  65                 return ret;
  66         }
  67
  68         ret = auxiliary_device_add(&client->aux_dev);
  69         if (ret) {
  70                 auxiliary_device_uninit(&client->aux_dev);
  71                 return ret;
  72         }
  73
  74         ret = devm_add_action_or_reset(&qseecom_dev->dev, qseecom_client_remove, client);
  75         if (ret)
  76                 return ret;
  77
  78         return 0;
  79 }
  80
  81 /*
  82  * List of supported applications. One client device will be created per entry,
  83  * assuming the app has already been loaded (usually by firmware bootloaders)
  84  * and its ID can be queried successfully.
  85  */
  86 static const struct qseecom_app_desc qcom_qseecom_apps[] = {
  87         { "qcom.tz.uefisecapp", "uefisecapp" },
  88 };
  89
  90 static int qcom_qseecom_probe(struct platform_device *qseecom_dev)
  91 {
  92         int ret;
  93         int i;
  94
  95         /* Set up client devices for each base application */
  96         for (i = 0; i < ARRAY_SIZE(qcom_qseecom_apps); i++) {
  97                 ret = qseecom_client_register(qseecom_dev, &qcom_qseecom_apps[i]);
  98                 if (ret)
  99                         return ret;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static struct platform_driver qcom_qseecom_driver = {
 106         .driver = {
 107                 .name   = "qcom_qseecom",
 108         },
 109         .probe = qcom_qseecom_probe,
 110 };
 111
 112 static int __init qcom_qseecom_init(void)
 113 {
 114         return platform_driver_register(&qcom_qseecom_driver);
 115 }
 116 subsys_initcall(qcom_qseecom_init);
 117
 118 MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
 119 MODULE_DESCRIPTION("Driver for the Qualcomm SEE (QSEECOM) interface");
 120 MODULE_LICENSE("GPL");