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/delay.h> 15 #include <linux/module.h> 16 #include <linux/pci.h> 17 #include <linux/slab.h> 18 #include <linux/mei.h> 19 #include <linux/mei_cl_bus.h> 20 #include <linux/component.h> 21 #include <drm/drm_connector.h> 22 #include <drm/intel/i915_component.h> 23 #include <drm/intel/i915_pxp_tee_interface.h> 24 25 #include "mei_pxp.h" 26 27 static inline int mei_pxp_reenable(const struct device *dev, struct mei_cl_device *cldev) 28 { 29 int ret; 30 31 dev_warn(dev, "Trying to reset the channel...\n"); 32 ret = mei_cldev_disable(cldev); 33 if (ret < 0) 34 dev_warn(dev, "mei_cldev_disable failed. %d\n", ret); 35 /* 36 * Explicitly ignoring disable failure, 37 * enable may fix the states and succeed 38 */ 39 ret = mei_cldev_enable(cldev); 40 if (ret < 0) 41 dev_err(dev, "mei_cldev_enable failed. %d\n", ret); 42 return ret; 43 } 44 45 /** 46 * mei_pxp_send_message() - Sends a PXP message to ME FW. 47 * @dev: device corresponding to the mei_cl_device 48 * @message: a message buffer to send 49 * @size: size of the message 50 * @timeout_ms: timeout in milliseconds, zero means wait indefinitely. 51 * 52 * Returns: 0 on Success, <0 on Failure with the following defined failures. 53 * -ENODEV: Client was not connected. 54 * Caller may attempt to try again immediately. 55 * -ENOMEM: Internal memory allocation failure experienced. 56 * Caller may sleep to allow kernel reclaim before retrying. 57 * -EINTR : Calling thread received a signal. Caller may choose 58 * to abandon with the same thread id. 59 * -ETIME : Request is timed out. 60 * Caller may attempt to try again immediately. 61 */ 62 static int 63 mei_pxp_send_message(struct device *dev, const void *message, size_t size, unsigned long timeout_ms) 64 { 65 struct mei_cl_device *cldev; 66 ssize_t byte; 67 int ret; 68 69 if (!dev || !message) 70 return -EINVAL; 71 72 cldev = to_mei_cl_device(dev); 73 74 byte = mei_cldev_send_timeout(cldev, message, size, timeout_ms); 75 if (byte < 0) { 76 dev_dbg(dev, "mei_cldev_send failed. %zd\n", byte); 77 switch (byte) { 78 case -ENOMEM: 79 fallthrough; 80 case -ENODEV: 81 fallthrough; 82 case -ETIME: 83 ret = mei_pxp_reenable(dev, cldev); 84 if (ret) 85 byte = ret; 86 break; 87 } 88 return byte; 89 } 90 91 return 0; 92 } 93 94 /** 95 * mei_pxp_receive_message() - Receives a PXP message from ME FW. 96 * @dev: device corresponding to the mei_cl_device 97 * @buffer: a message buffer to contain the received message 98 * @size: size of the buffer 99 * @timeout_ms: timeout in milliseconds, zero means wait indefinitely. 100 * 101 * Returns: number of bytes send on Success, <0 on Failure with the following defined failures. 102 * -ENODEV: Client was not connected. 103 * Caller may attempt to try again from send immediately. 104 * -ENOMEM: Internal memory allocation failure experienced. 105 * Caller may sleep to allow kernel reclaim before retrying. 106 * -EINTR : Calling thread received a signal. Caller will need to repeat calling 107 * (with a different owning thread) to retrieve existing unclaimed response 108 * (and may discard it). 109 * -ETIME : Request is timed out. 110 * Caller may attempt to try again from send immediately. 111 */ 112 static int 113 mei_pxp_receive_message(struct device *dev, void *buffer, size_t size, unsigned long timeout_ms) 114 { 115 struct mei_cl_device *cldev; 116 ssize_t byte; 117 bool retry = false; 118 int ret; 119 120 if (!dev || !buffer) 121 return -EINVAL; 122 123 cldev = to_mei_cl_device(dev); 124 125 retry: 126 byte = mei_cldev_recv_timeout(cldev, buffer, size, timeout_ms); 127 if (byte < 0) { 128 dev_dbg(dev, "mei_cldev_recv failed. %zd\n", byte); 129 switch (byte) { 130 case -ENOMEM: 131 /* Retry the read when pages are reclaimed */ 132 msleep(20); 133 if (!retry) { 134 retry = true; 135 goto retry; 136 } 137 fallthrough; 138 case -ENODEV: 139 fallthrough; 140 case -ETIME: 141 ret = mei_pxp_reenable(dev, cldev); 142 if (ret) 143 byte = ret; 144 break; 145 } 146 } 147 148 return byte; 149 } 150 151 /** 152 * mei_pxp_gsc_command() - sends a gsc command, by sending 153 * a sgl mei message to gsc and receiving reply from gsc 154 * 155 * @dev: device corresponding to the mei_cl_device 156 * @client_id: client id to send the command to 157 * @fence_id: fence id to send the command to 158 * @sg_in: scatter gather list containing addresses for rx message buffer 159 * @total_in_len: total length of data in 'in' sg, can be less than the sum of buffers sizes 160 * @sg_out: scatter gather list containing addresses for tx message buffer 161 * 162 * Return: bytes sent on Success, <0 on Failure 163 */ 164 static ssize_t mei_pxp_gsc_command(struct device *dev, u8 client_id, u32 fence_id, 165 struct scatterlist *sg_in, size_t total_in_len, 166 struct scatterlist *sg_out) 167 { 168 struct mei_cl_device *cldev; 169 170 cldev = to_mei_cl_device(dev); 171 172 return mei_cldev_send_gsc_command(cldev, client_id, fence_id, sg_in, total_in_len, sg_out); 173 } 174 175 static const struct i915_pxp_component_ops mei_pxp_ops = { 176 .owner = THIS_MODULE, 177 .send = mei_pxp_send_message, 178 .recv = mei_pxp_receive_message, 179 .gsc_command = mei_pxp_gsc_command, 180 }; 181 182 static int mei_component_master_bind(struct device *dev) 183 { 184 struct mei_cl_device *cldev = to_mei_cl_device(dev); 185 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 186 int ret; 187 188 comp_master->ops = &mei_pxp_ops; 189 comp_master->tee_dev = dev; 190 ret = component_bind_all(dev, comp_master); 191 if (ret < 0) 192 return ret; 193 194 return 0; 195 } 196 197 static void mei_component_master_unbind(struct device *dev) 198 { 199 struct mei_cl_device *cldev = to_mei_cl_device(dev); 200 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 201 202 component_unbind_all(dev, comp_master); 203 } 204 205 static const struct component_master_ops mei_component_master_ops = { 206 .bind = mei_component_master_bind, 207 .unbind = mei_component_master_unbind, 208 }; 209 210 /** 211 * mei_pxp_component_match - compare function for matching mei pxp. 212 * 213 * The function checks if the driver is i915, the subcomponent is PXP 214 * and the grand parent of pxp and the parent of i915 are the same 215 * PCH device. 216 * 217 * @dev: master device 218 * @subcomponent: subcomponent to match (I915_COMPONENT_PXP) 219 * @data: compare data (mei pxp device) 220 * 221 * Return: 222 * * 1 - if components match 223 * * 0 - otherwise 224 */ 225 static int mei_pxp_component_match(struct device *dev, int subcomponent, 226 void *data) 227 { 228 struct device *base = data; 229 struct pci_dev *pdev; 230 231 if (!dev) 232 return 0; 233 234 if (!dev_is_pci(dev)) 235 return 0; 236 237 pdev = to_pci_dev(dev); 238 239 if (pdev->vendor != PCI_VENDOR_ID_INTEL) 240 return 0; 241 242 if (pdev->class != (PCI_CLASS_DISPLAY_VGA << 8) && 243 pdev->class != (PCI_CLASS_DISPLAY_OTHER << 8)) 244 return 0; 245 246 if (subcomponent != I915_COMPONENT_PXP) 247 return 0; 248 249 base = base->parent; 250 if (!base) /* mei device */ 251 return 0; 252 253 base = base->parent; /* pci device */ 254 /* for dgfx */ 255 if (base && dev == base) 256 return 1; 257 258 /* for pch */ 259 dev = dev->parent; 260 return (base && dev && dev == base); 261 } 262 263 static int mei_pxp_probe(struct mei_cl_device *cldev, 264 const struct mei_cl_device_id *id) 265 { 266 struct i915_pxp_component *comp_master; 267 struct component_match *master_match; 268 int ret; 269 270 ret = mei_cldev_enable(cldev); 271 if (ret < 0) { 272 dev_err(&cldev->dev, "mei_cldev_enable Failed. %d\n", ret); 273 goto enable_err_exit; 274 } 275 276 comp_master = kzalloc(sizeof(*comp_master), GFP_KERNEL); 277 if (!comp_master) { 278 ret = -ENOMEM; 279 goto err_exit; 280 } 281 282 master_match = NULL; 283 component_match_add_typed(&cldev->dev, &master_match, 284 mei_pxp_component_match, &cldev->dev); 285 if (IS_ERR_OR_NULL(master_match)) { 286 ret = -ENOMEM; 287 goto err_exit; 288 } 289 290 mei_cldev_set_drvdata(cldev, comp_master); 291 ret = component_master_add_with_match(&cldev->dev, 292 &mei_component_master_ops, 293 master_match); 294 if (ret < 0) { 295 dev_err(&cldev->dev, "Master comp add failed %d\n", ret); 296 goto err_exit; 297 } 298 299 return 0; 300 301 err_exit: 302 mei_cldev_set_drvdata(cldev, NULL); 303 kfree(comp_master); 304 mei_cldev_disable(cldev); 305 enable_err_exit: 306 return ret; 307 } 308 309 static void mei_pxp_remove(struct mei_cl_device *cldev) 310 { 311 struct i915_pxp_component *comp_master = mei_cldev_get_drvdata(cldev); 312 int ret; 313 314 component_master_del(&cldev->dev, &mei_component_master_ops); 315 kfree(comp_master); 316 mei_cldev_set_drvdata(cldev, NULL); 317 318 ret = mei_cldev_disable(cldev); 319 if (ret) 320 dev_warn(&cldev->dev, "mei_cldev_disable() failed\n"); 321 } 322 323 /* fbf6fcf1-96cf-4e2e-a6a6-1bab8cbe36b1 : PAVP GUID*/ 324 #define MEI_GUID_PXP UUID_LE(0xfbf6fcf1, 0x96cf, 0x4e2e, 0xA6, \ 325 0xa6, 0x1b, 0xab, 0x8c, 0xbe, 0x36, 0xb1) 326 327 static struct mei_cl_device_id mei_pxp_tbl[] = { 328 { .uuid = MEI_GUID_PXP, .version = MEI_CL_VERSION_ANY }, 329 { } 330 }; 331 MODULE_DEVICE_TABLE(mei, mei_pxp_tbl); 332 333 static struct mei_cl_driver mei_pxp_driver = { 334 .id_table = mei_pxp_tbl, 335 .name = KBUILD_MODNAME, 336 .probe = mei_pxp_probe, 337 .remove = mei_pxp_remove, 338 }; 339 340 module_mei_cl_driver(mei_pxp_driver); 341 342 MODULE_AUTHOR("Intel Corporation"); 343 MODULE_LICENSE("GPL"); 344 MODULE_DESCRIPTION("MEI PXP"); 345