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 24 struct rpi_firmware { 25 struct mbox_client cl; 26 struct mbox_chan *chan; /* The property channel. */ 27 struct completion c; 28 u32 enabled; 29 }; 30 31 static DEFINE_MUTEX(transaction_lock); 32 33 static void response_callback(struct mbox_client *cl, void *msg) 34 { 35 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); 36 complete(&fw->c); 37 } 38 39 /* 40 * Sends a request to the firmware through the BCM2835 mailbox driver, 41 * and synchronously waits for the reply. 42 */ 43 static int 44 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) 45 { 46 u32 message = MBOX_MSG(chan, data); 47 int ret; 48 49 WARN_ON(data & 0xf); 50 51 mutex_lock(&transaction_lock); 52 reinit_completion(&fw->c); 53 ret = mbox_send_message(fw->chan, &message); 54 if (ret >= 0) { 55 if (wait_for_completion_timeout(&fw->c, HZ)) { 56 ret = 0; 57 } else { 58 ret = -ETIMEDOUT; 59 WARN_ONCE(1, "Firmware transaction timeout"); 60 } 61 } else { 62 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret); 63 } 64 mutex_unlock(&transaction_lock); 65 66 return ret; 67 } 68 69 /** 70 * rpi_firmware_property_list - Submit firmware property list 71 * @fw: Pointer to firmware structure from rpi_firmware_get(). 72 * @data: Buffer holding tags. 73 * @tag_size: Size of tags buffer. 74 * 75 * Submits a set of concatenated tags to the VPU firmware through the 76 * mailbox property interface. 77 * 78 * The buffer header and the ending tag are added by this function and 79 * don't need to be supplied, just the actual tags for your operation. 80 * See struct rpi_firmware_property_tag_header for the per-tag 81 * structure. 82 */ 83 int rpi_firmware_property_list(struct rpi_firmware *fw, 84 void *data, size_t tag_size) 85 { 86 size_t size = tag_size + 12; 87 u32 *buf; 88 dma_addr_t bus_addr; 89 int ret; 90 91 /* Packets are processed a dword at a time. */ 92 if (size & 3) 93 return -EINVAL; 94 95 buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr, 96 GFP_ATOMIC); 97 if (!buf) 98 return -ENOMEM; 99 100 /* The firmware will error out without parsing in this case. */ 101 WARN_ON(size >= 1024 * 1024); 102 103 buf[0] = size; 104 buf[1] = RPI_FIRMWARE_STATUS_REQUEST; 105 memcpy(&buf[2], data, tag_size); 106 buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END; 107 wmb(); 108 109 ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr); 110 111 rmb(); 112 memcpy(data, &buf[2], tag_size); 113 if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) { 114 /* 115 * The tag name here might not be the one causing the 116 * error, if there were multiple tags in the request. 117 * But single-tag is the most common, so go with it. 118 */ 119 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n", 120 buf[2], buf[1]); 121 ret = -EINVAL; 122 } 123 124 dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr); 125 126 return ret; 127 } 128 EXPORT_SYMBOL_GPL(rpi_firmware_property_list); 129 130 /** 131 * rpi_firmware_property - Submit single firmware property 132 * @fw: Pointer to firmware structure from rpi_firmware_get(). 133 * @tag: One of enum_mbox_property_tag. 134 * @tag_data: Tag data buffer. 135 * @buf_size: Buffer size. 136 * 137 * Submits a single tag to the VPU firmware through the mailbox 138 * property interface. 139 * 140 * This is a convenience wrapper around 141 * rpi_firmware_property_list() to avoid some of the 142 * boilerplate in property calls. 143 */ 144 int rpi_firmware_property(struct rpi_firmware *fw, 145 u32 tag, void *tag_data, size_t buf_size) 146 { 147 struct rpi_firmware_property_tag_header *header; 148 int ret; 149 150 /* Some mailboxes can use over 1k bytes. Rather than checking 151 * size and using stack or kmalloc depending on requirements, 152 * just use kmalloc. Mailboxes don't get called enough to worry 153 * too much about the time taken in the allocation. 154 */ 155 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL); 156 157 if (!data) 158 return -ENOMEM; 159 160 header = data; 161 header->tag = tag; 162 header->buf_size = buf_size; 163 header->req_resp_size = 0; 164 memcpy(data + sizeof(*header), tag_data, buf_size); 165 166 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header)); 167 168 memcpy(tag_data, data + sizeof(*header), buf_size); 169 170 kfree(data); 171 172 return ret; 173 } 174 EXPORT_SYMBOL_GPL(rpi_firmware_property); 175 176 static void 177 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) 178 { 179 u32 packet; 180 int ret = rpi_firmware_property(fw, 181 RPI_FIRMWARE_GET_FIRMWARE_REVISION, 182 &packet, sizeof(packet)); 183 184 if (ret == 0) { 185 struct tm tm; 186 187 time64_to_tm(packet, 0, &tm); 188 189 dev_info(fw->cl.dev, 190 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n", 191 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 192 tm.tm_hour, tm.tm_min); 193 } 194 } 195 196 static void 197 rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) 198 { 199 u32 packet; 200 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, 201 &packet, sizeof(packet)); 202 203 if (ret) 204 return; 205 206 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", 207 -1, NULL, 0); 208 } 209 210 static int rpi_firmware_probe(struct platform_device *pdev) 211 { 212 struct device *dev = &pdev->dev; 213 struct rpi_firmware *fw; 214 215 fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); 216 if (!fw) 217 return -ENOMEM; 218 219 fw->cl.dev = dev; 220 fw->cl.rx_callback = response_callback; 221 fw->cl.tx_block = true; 222 223 fw->chan = mbox_request_channel(&fw->cl, 0); 224 if (IS_ERR(fw->chan)) { 225 int ret = PTR_ERR(fw->chan); 226 if (ret != -EPROBE_DEFER) 227 dev_err(dev, "Failed to get mbox channel: %d\n", ret); 228 return ret; 229 } 230 231 init_completion(&fw->c); 232 233 platform_set_drvdata(pdev, fw); 234 235 rpi_firmware_print_firmware_revision(fw); 236 rpi_register_hwmon_driver(dev, fw); 237 238 return 0; 239 } 240 241 static void rpi_firmware_shutdown(struct platform_device *pdev) 242 { 243 struct rpi_firmware *fw = platform_get_drvdata(pdev); 244 245 if (!fw) 246 return; 247 248 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0); 249 } 250 251 static int rpi_firmware_remove(struct platform_device *pdev) 252 { 253 struct rpi_firmware *fw = platform_get_drvdata(pdev); 254 255 platform_device_unregister(rpi_hwmon); 256 rpi_hwmon = NULL; 257 mbox_free_channel(fw->chan); 258 259 return 0; 260 } 261 262 /** 263 * rpi_firmware_get - Get pointer to rpi_firmware structure. 264 * @firmware_node: Pointer to the firmware Device Tree node. 265 * 266 * Returns NULL is the firmware device is not ready. 267 */ 268 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) 269 { 270 struct platform_device *pdev = of_find_device_by_node(firmware_node); 271 272 if (!pdev) 273 return NULL; 274 275 return platform_get_drvdata(pdev); 276 } 277 EXPORT_SYMBOL_GPL(rpi_firmware_get); 278 279 static const struct of_device_id rpi_firmware_of_match[] = { 280 { .compatible = "raspberrypi,bcm2835-firmware", }, 281 {}, 282 }; 283 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); 284 285 static struct platform_driver rpi_firmware_driver = { 286 .driver = { 287 .name = "raspberrypi-firmware", 288 .of_match_table = rpi_firmware_of_match, 289 }, 290 .probe = rpi_firmware_probe, 291 .shutdown = rpi_firmware_shutdown, 292 .remove = rpi_firmware_remove, 293 }; 294 module_platform_driver(rpi_firmware_driver); 295 296 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); 297 MODULE_DESCRIPTION("Raspberry Pi firmware driver"); 298 MODULE_LICENSE("GPL v2"); 299