1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Defines interfaces for interacting wtih the Raspberry Pi firmware's 4 * property channel. 5 * 6 * Copyright © 2015 Broadcom 7 */ 8 9 #include <linux/dma-mapping.h> 10 #include <linux/mailbox_client.h> 11 #include <linux/module.h> 12 #include <linux/of_platform.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 #include <soc/bcm2835/raspberrypi-firmware.h> 16 17 #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) 18 #define MBOX_CHAN(msg) ((msg) & 0xf) 19 #define MBOX_DATA28(msg) ((msg) & ~0xf) 20 #define MBOX_CHAN_PROPERTY 8 21 22 static struct platform_device *rpi_hwmon; 23 static struct platform_device *rpi_clk; 24 25 struct rpi_firmware { 26 struct mbox_client cl; 27 struct mbox_chan *chan; /* The property channel. */ 28 struct completion c; 29 u32 enabled; 30 }; 31 32 static DEFINE_MUTEX(transaction_lock); 33 34 static void response_callback(struct mbox_client *cl, void *msg) 35 { 36 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); 37 complete(&fw->c); 38 } 39 40 /* 41 * Sends a request to the firmware through the BCM2835 mailbox driver, 42 * and synchronously waits for the reply. 43 */ 44 static int 45 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) 46 { 47 u32 message = MBOX_MSG(chan, data); 48 int ret; 49 50 WARN_ON(data & 0xf); 51 52 mutex_lock(&transaction_lock); 53 reinit_completion(&fw->c); 54 ret = mbox_send_message(fw->chan, &message); 55 if (ret >= 0) { 56 if (wait_for_completion_timeout(&fw->c, HZ)) { 57 ret = 0; 58 } else { 59 ret = -ETIMEDOUT; 60 WARN_ONCE(1, "Firmware transaction timeout"); 61 } 62 } else { 63 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret); 64 } 65 mutex_unlock(&transaction_lock); 66 67 return ret; 68 } 69 70 /** 71 * rpi_firmware_property_list - Submit firmware property list 72 * @fw: Pointer to firmware structure from rpi_firmware_get(). 73 * @data: Buffer holding tags. 74 * @tag_size: Size of tags buffer. 75 * 76 * Submits a set of concatenated tags to the VPU firmware through the 77 * mailbox property interface. 78 * 79 * The buffer header and the ending tag are added by this function and 80 * don't need to be supplied, just the actual tags for your operation. 81 * See struct rpi_firmware_property_tag_header for the per-tag 82 * structure. 83 */ 84 int rpi_firmware_property_list(struct rpi_firmware *fw, 85 void *data, size_t tag_size) 86 { 87 size_t size = tag_size + 12; 88 u32 *buf; 89 dma_addr_t bus_addr; 90 int ret; 91 92 /* Packets are processed a dword at a time. */ 93 if (size & 3) 94 return -EINVAL; 95 96 buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr, 97 GFP_ATOMIC); 98 if (!buf) 99 return -ENOMEM; 100 101 /* The firmware will error out without parsing in this case. */ 102 WARN_ON(size >= 1024 * 1024); 103 104 buf[0] = size; 105 buf[1] = RPI_FIRMWARE_STATUS_REQUEST; 106 memcpy(&buf[2], data, tag_size); 107 buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END; 108 wmb(); 109 110 ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr); 111 112 rmb(); 113 memcpy(data, &buf[2], tag_size); 114 if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) { 115 /* 116 * The tag name here might not be the one causing the 117 * error, if there were multiple tags in the request. 118 * But single-tag is the most common, so go with it. 119 */ 120 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n", 121 buf[2], buf[1]); 122 ret = -EINVAL; 123 } 124 125 dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr); 126 127 return ret; 128 } 129 EXPORT_SYMBOL_GPL(rpi_firmware_property_list); 130 131 /** 132 * rpi_firmware_property - Submit single firmware property 133 * @fw: Pointer to firmware structure from rpi_firmware_get(). 134 * @tag: One of enum_mbox_property_tag. 135 * @tag_data: Tag data buffer. 136 * @buf_size: Buffer size. 137 * 138 * Submits a single tag to the VPU firmware through the mailbox 139 * property interface. 140 * 141 * This is a convenience wrapper around 142 * rpi_firmware_property_list() to avoid some of the 143 * boilerplate in property calls. 144 */ 145 int rpi_firmware_property(struct rpi_firmware *fw, 146 u32 tag, void *tag_data, size_t buf_size) 147 { 148 struct rpi_firmware_property_tag_header *header; 149 int ret; 150 151 /* Some mailboxes can use over 1k bytes. Rather than checking 152 * size and using stack or kmalloc depending on requirements, 153 * just use kmalloc. Mailboxes don't get called enough to worry 154 * too much about the time taken in the allocation. 155 */ 156 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL); 157 158 if (!data) 159 return -ENOMEM; 160 161 header = data; 162 header->tag = tag; 163 header->buf_size = buf_size; 164 header->req_resp_size = 0; 165 memcpy(data + sizeof(*header), tag_data, buf_size); 166 167 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header)); 168 169 memcpy(tag_data, data + sizeof(*header), buf_size); 170 171 kfree(data); 172 173 return ret; 174 } 175 EXPORT_SYMBOL_GPL(rpi_firmware_property); 176 177 static void 178 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) 179 { 180 time64_t date_and_time; 181 u32 packet; 182 int ret = rpi_firmware_property(fw, 183 RPI_FIRMWARE_GET_FIRMWARE_REVISION, 184 &packet, sizeof(packet)); 185 186 if (ret) 187 return; 188 189 /* This is not compatible with y2038 */ 190 date_and_time = packet; 191 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time); 192 } 193 194 static void 195 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) 196 { 197 u32 packet; 198 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, 199 &packet, sizeof(packet)); 200 201 if (ret) 202 return; 203 204 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", 205 -1, NULL, 0); 206 } 207 208 static void rpi_register_clk_driver(struct device *dev) 209 { 210 struct device_node *firmware; 211 212 /* 213 * Earlier DTs don't have a node for the firmware clocks but 214 * rely on us creating a platform device by hand. If we do 215 * have a node for the firmware clocks, just bail out here. 216 */ 217 firmware = of_get_compatible_child(dev->of_node, 218 "raspberrypi,firmware-clocks"); 219 if (firmware) { 220 of_node_put(firmware); 221 return; 222 } 223 224 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk", 225 -1, NULL, 0); 226 } 227 228 static int rpi_firmware_probe(struct platform_device *pdev) 229 { 230 struct device *dev = &pdev->dev; 231 struct rpi_firmware *fw; 232 233 fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); 234 if (!fw) 235 return -ENOMEM; 236 237 fw->cl.dev = dev; 238 fw->cl.rx_callback = response_callback; 239 fw->cl.tx_block = true; 240 241 fw->chan = mbox_request_channel(&fw->cl, 0); 242 if (IS_ERR(fw->chan)) { 243 int ret = PTR_ERR(fw->chan); 244 if (ret != -EPROBE_DEFER) 245 dev_err(dev, "Failed to get mbox channel: %d\n", ret); 246 return ret; 247 } 248 249 init_completion(&fw->c); 250 251 platform_set_drvdata(pdev, fw); 252 253 rpi_firmware_print_firmware_revision(fw); 254 rpi_register_hwmon_driver(dev, fw); 255 rpi_register_clk_driver(dev); 256 257 return 0; 258 } 259 260 static void rpi_firmware_shutdown(struct platform_device *pdev) 261 { 262 struct rpi_firmware *fw = platform_get_drvdata(pdev); 263 264 if (!fw) 265 return; 266 267 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0); 268 } 269 270 static int rpi_firmware_remove(struct platform_device *pdev) 271 { 272 struct rpi_firmware *fw = platform_get_drvdata(pdev); 273 274 platform_device_unregister(rpi_hwmon); 275 rpi_hwmon = NULL; 276 platform_device_unregister(rpi_clk); 277 rpi_clk = NULL; 278 mbox_free_channel(fw->chan); 279 280 return 0; 281 } 282 283 /** 284 * rpi_firmware_get - Get pointer to rpi_firmware structure. 285 * @firmware_node: Pointer to the firmware Device Tree node. 286 * 287 * Returns NULL is the firmware device is not ready. 288 */ 289 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) 290 { 291 struct platform_device *pdev = of_find_device_by_node(firmware_node); 292 293 if (!pdev) 294 return NULL; 295 296 return platform_get_drvdata(pdev); 297 } 298 EXPORT_SYMBOL_GPL(rpi_firmware_get); 299 300 static const struct of_device_id rpi_firmware_of_match[] = { 301 { .compatible = "raspberrypi,bcm2835-firmware", }, 302 {}, 303 }; 304 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); 305 306 static struct platform_driver rpi_firmware_driver = { 307 .driver = { 308 .name = "raspberrypi-firmware", 309 .of_match_table = rpi_firmware_of_match, 310 }, 311 .probe = rpi_firmware_probe, 312 .shutdown = rpi_firmware_shutdown, 313 .remove = rpi_firmware_remove, 314 }; 315 module_platform_driver(rpi_firmware_driver); 316 317 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); 318 MODULE_DESCRIPTION("Raspberry Pi firmware driver"); 319 MODULE_LICENSE("GPL v2"); 320