1 /* 2 * Defines interfaces for interacting wtih the Raspberry Pi firmware's 3 * property channel. 4 * 5 * Copyright © 2015 Broadcom 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 12 #include <linux/dma-mapping.h> 13 #include <linux/mailbox_client.h> 14 #include <linux/module.h> 15 #include <linux/of_platform.h> 16 #include <linux/platform_device.h> 17 #include <soc/bcm2835/raspberrypi-firmware.h> 18 19 #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) 20 #define MBOX_CHAN(msg) ((msg) & 0xf) 21 #define MBOX_DATA28(msg) ((msg) & ~0xf) 22 #define MBOX_CHAN_PROPERTY 8 23 24 #define MAX_RPI_FW_PROP_BUF_SIZE 32 25 26 static struct platform_device *rpi_hwmon; 27 28 struct rpi_firmware { 29 struct mbox_client cl; 30 struct mbox_chan *chan; /* The property channel. */ 31 struct completion c; 32 u32 enabled; 33 }; 34 35 static DEFINE_MUTEX(transaction_lock); 36 37 static void response_callback(struct mbox_client *cl, void *msg) 38 { 39 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); 40 complete(&fw->c); 41 } 42 43 /* 44 * Sends a request to the firmware through the BCM2835 mailbox driver, 45 * and synchronously waits for the reply. 46 */ 47 static int 48 rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) 49 { 50 u32 message = MBOX_MSG(chan, data); 51 int ret; 52 53 WARN_ON(data & 0xf); 54 55 mutex_lock(&transaction_lock); 56 reinit_completion(&fw->c); 57 ret = mbox_send_message(fw->chan, &message); 58 if (ret >= 0) { 59 wait_for_completion(&fw->c); 60 ret = 0; 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 /* Single tags are very small (generally 8 bytes), so the 148 * stack should be safe. 149 */ 150 u8 data[sizeof(struct rpi_firmware_property_tag_header) + 151 MAX_RPI_FW_PROP_BUF_SIZE]; 152 struct rpi_firmware_property_tag_header *header = 153 (struct rpi_firmware_property_tag_header *)data; 154 int ret; 155 156 if (WARN_ON(buf_size > sizeof(data) - sizeof(*header))) 157 return -EINVAL; 158 159 header->tag = tag; 160 header->buf_size = buf_size; 161 header->req_resp_size = 0; 162 memcpy(data + sizeof(struct rpi_firmware_property_tag_header), 163 tag_data, buf_size); 164 165 ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header)); 166 memcpy(tag_data, 167 data + sizeof(struct rpi_firmware_property_tag_header), 168 buf_size); 169 170 return ret; 171 } 172 EXPORT_SYMBOL_GPL(rpi_firmware_property); 173 174 static void 175 rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) 176 { 177 u32 packet; 178 int ret = rpi_firmware_property(fw, 179 RPI_FIRMWARE_GET_FIRMWARE_REVISION, 180 &packet, sizeof(packet)); 181 182 if (ret == 0) { 183 struct tm tm; 184 185 time64_to_tm(packet, 0, &tm); 186 187 dev_info(fw->cl.dev, 188 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n", 189 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, 190 tm.tm_hour, tm.tm_min); 191 } 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 int rpi_firmware_probe(struct platform_device *pdev) 209 { 210 struct device *dev = &pdev->dev; 211 struct rpi_firmware *fw; 212 213 fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL); 214 if (!fw) 215 return -ENOMEM; 216 217 fw->cl.dev = dev; 218 fw->cl.rx_callback = response_callback; 219 fw->cl.tx_block = true; 220 221 fw->chan = mbox_request_channel(&fw->cl, 0); 222 if (IS_ERR(fw->chan)) { 223 int ret = PTR_ERR(fw->chan); 224 if (ret != -EPROBE_DEFER) 225 dev_err(dev, "Failed to get mbox channel: %d\n", ret); 226 return ret; 227 } 228 229 init_completion(&fw->c); 230 231 platform_set_drvdata(pdev, fw); 232 233 rpi_firmware_print_firmware_revision(fw); 234 rpi_register_hwmon_driver(dev, fw); 235 236 return 0; 237 } 238 239 static int rpi_firmware_remove(struct platform_device *pdev) 240 { 241 struct rpi_firmware *fw = platform_get_drvdata(pdev); 242 243 platform_device_unregister(rpi_hwmon); 244 rpi_hwmon = NULL; 245 mbox_free_channel(fw->chan); 246 247 return 0; 248 } 249 250 /** 251 * rpi_firmware_get - Get pointer to rpi_firmware structure. 252 * @firmware_node: Pointer to the firmware Device Tree node. 253 * 254 * Returns NULL is the firmware device is not ready. 255 */ 256 struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) 257 { 258 struct platform_device *pdev = of_find_device_by_node(firmware_node); 259 260 if (!pdev) 261 return NULL; 262 263 return platform_get_drvdata(pdev); 264 } 265 EXPORT_SYMBOL_GPL(rpi_firmware_get); 266 267 static const struct of_device_id rpi_firmware_of_match[] = { 268 { .compatible = "raspberrypi,bcm2835-firmware", }, 269 {}, 270 }; 271 MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); 272 273 static struct platform_driver rpi_firmware_driver = { 274 .driver = { 275 .name = "raspberrypi-firmware", 276 .of_match_table = rpi_firmware_of_match, 277 }, 278 .probe = rpi_firmware_probe, 279 .remove = rpi_firmware_remove, 280 }; 281 module_platform_driver(rpi_firmware_driver); 282 283 MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); 284 MODULE_DESCRIPTION("Raspberry Pi firmware driver"); 285 MODULE_LICENSE("GPL v2"); 286