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| 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"); |
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