1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright © 2020 - 2021 Intel Corporation 4 */ 5 6 /** 7 * DOC: MEI_PXP Client Driver 8 * 9 * The mei_pxp driver acts as a translation layer between PXP 10 * protocol implementer (I915) and ME FW by translating PXP 11 * negotiation messages to ME FW command payloads and vice versa. 12 */ 13 14 #include <linux/module.h> 15 #include <linux/slab.h> 16 #include <linux/uuid.h> 17 #include <linux/mei_cl_bus.h> 18 #include <linux/component.h> 19 #include <drm/drm_connector.h> 20 #include <drm/i915_component.h> 21 #include <drm/i915_pxp_tee_interface.h> 22 23 #include "mei_pxp.h" 24 25 /** 26 * mei_pxp_send_message() - Sends a PXP message to ME FW. 27 * @dev: device corresponding to the mei_cl_device 28 * @message: a message buffer to send 29 * @size: size of the message 30 * Return: 0 on Success, <0 on Failure 31 */ 32 static int 33 mei_pxp_send_message(struct device *dev, const void *message, size_t size) 34 { 35 struct mei_cl_device *cldev; 36 ssize_t byte; 37 38 if (!dev || !message) 39 return -EINVAL; 40 41 cldev = to_mei_cl_device(dev); 42 43 /* temporary drop const qualifier till the API is fixed */ 44 byte = mei_cldev_send(cldev, (u8 *)message, size); 45 if (byte < 0) { 46 dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte); 47 return byte; 48 } 49 50 return 0; 51 } 52 53 /** 54 * mei_pxp_receive_message() - Receives a PXP message from ME FW. 55 * @dev: device corresponding to the mei_cl_device 56 * @buffer: a message buffer to contain the received message 57 * @size: size of the buffer 58 * Return: bytes sent on Success, <0 on Failure 59 */ 60 static int 61 mei_pxp_receive_message(struct device *dev, void *buffer, size_t size) 62 { 63 struct mei_cl_device *cldev; 64 ssize_t byte; 65 66 if (!dev || !buffer) 67 return -EINVAL; 68 69 cldev = to_mei_cl_device(dev); 70 71 byte = mei_cldev_recv(cldev, buffer, size); 72 if (byte < 0) { 73 dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte); 74 return byte; 75 } 76 77 return byte; 78 } 79 80 static const struct i915_pxp_component_ops mei_pxp_ops = { 81 .owner = THIS_MODULE, 82 .send = mei_pxp_send_message, 83 .recv = mei_pxp_receive_message, 84 }; 85 86 static int mei_component_master_bind(struct device *dev) 87 { 88 struct mei_cl_device *cldev = to_mei_cl_device(dev); 89 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 90 int ret; 91 92 comp_master->ops = &mei_pxp_ops; 93 comp_master->tee_dev = dev; 94 ret = component_bind_all(dev, comp_master); 95 if (ret < 0) 96 return ret; 97 98 return 0; 99 } 100 101 static void mei_component_master_unbind(struct device *dev) 102 { 103 struct mei_cl_device *cldev = to_mei_cl_device(dev); 104 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 105 106 component_unbind_all(dev, comp_master); 107 } 108 109 static const struct component_master_ops mei_component_master_ops = { 110 .bind = mei_component_master_bind, 111 .unbind = mei_component_master_unbind, 112 }; 113 114 /** 115 * mei_pxp_component_match - compare function for matching mei pxp. 116 * 117 * The function checks if the driver is i915, the subcomponent is PXP 118 * and the grand parent of pxp and the parent of i915 are the same 119 * PCH device. 120 * 121 * @dev: master device 122 * @subcomponent: subcomponent to match (I915_COMPONENT_PXP) 123 * @data: compare data (mei pxp device) 124 * 125 * Return: 126 * * 1 - if components match 127 * * 0 - otherwise 128 */ 129 static int mei_pxp_component_match(struct device *dev, int subcomponent, 130 void *data) 131 { 132 struct device *base = data; 133 134 if (strcmp(dev->driver->name, "i915") || 135 subcomponent != I915_COMPONENT_PXP) 136 return 0; 137 138 base = base->parent; 139 if (!base) 140 return 0; 141 142 base = base->parent; 143 dev = dev->parent; 144 145 return (base && dev && dev == base); 146 } 147 148 static int mei_pxp_probe(struct mei_cl_device *cldev, 149 const struct mei_cl_device_id *id) 150 { 151 struct i915_pxp_component *comp_master; 152 struct component_match *master_match; 153 int ret; 154 155 ret = mei_cldev_enable(cldev); 156 if (ret < 0) { 157 dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret); 158 goto enable_err_exit; 159 } 160 161 comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL); 162 if (!comp_master) { 163 ret = -ENOMEM; 164 goto err_exit; 165 } 166 167 master_match = NULL; 168 component_match_add_typed(&cldev->dev, &master_match, 169 mei_pxp_component_match, &cldev->dev); 170 if (IS_ERR_OR_NULL(master_match)) { 171 ret = -ENOMEM; 172 goto err_exit; 173 } 174 175 mei_cldev_set_drvdata(cldev, comp_master); 176 ret = component_master_add_with_match(&cldev->dev, 177 &mei_component_master_ops, 178 master_match); 179 if (ret < 0) { 180 dev_err(&cldev->dev, "Master comp add failed %d\n", ret); 181 goto err_exit; 182 } 183 184 return 0; 185 186 err_exit: 187 mei_cldev_set_drvdata(cldev, NULL); 188 kfree(comp_master); 189 mei_cldev_disable(cldev); 190 enable_err_exit: 191 return ret; 192 } 193 194 static void mei_pxp_remove(struct mei_cl_device *cldev) 195 { 196 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 197 int ret; 198 199 component_master_del(&cldev->dev, &mei_component_master_ops); 200 kfree(comp_master); 201 mei_cldev_set_drvdata(cldev, NULL); 202 203 ret = mei_cldev_disable(cldev); 204 if (ret) 205 dev_warn(&cldev->dev, "mei_cldev_disable() failed\n"); 206 } 207 208 /* fbf6fcf1-96cf-4e2e-a6a6-1bab8cbe36b1 : PAVP GUID*/ 209 #define MEI_GUID_PXP GUID_INIT(0xfbf6fcf1, 0x96cf, 0x4e2e, 0xA6, \ 210 0xa6, 0x1b, 0xab, 0x8c, 0xbe, 0x36, 0xb1) 211 212 static struct mei_cl_device_id mei_pxp_tbl[] = { 213 { .uuid = MEI_GUID_PXP, .version = MEI_CL_VERSION_ANY }, 214 { } 215 }; 216 MODULE_DEVICE_TABLE(mei, mei_pxp_tbl); 217 218 static struct mei_cl_driver mei_pxp_driver = { 219 .id_table = mei_pxp_tbl, 220 .name = KBUILD_MODNAME, 221 .probe = mei_pxp_probe, 222 .remove = mei_pxp_remove, 223 }; 224 225 module_mei_cl_driver(mei_pxp_driver); 226 227 MODULE_AUTHOR("Intel Corporation"); 228 MODULE_LICENSE("GPL"); 229 MODULE_DESCRIPTION("MEI PXP"); 230