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1// SPDX-License-Identifier: GPL-2.02/*3 * Defines interfaces for interacting with the Raspberry Pi firmware's4 * property channel.5 *6 * Copyright © 2015 Broadcom7 */8 9#include <linux/dma-mapping.h>10#include <linux/kref.h>11#include <linux/mailbox_client.h>12#include <linux/mailbox_controller.h>13#include <linux/module.h>14#include <linux/of.h>15#include <linux/of_platform.h>16#include <linux/platform_device.h>17#include <linux/slab.h>18#include <soc/bcm2835/raspberrypi-firmware.h>19 20#define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf))21#define MBOX_CHAN(msg) ((msg) & 0xf)22#define MBOX_DATA28(msg) ((msg) & ~0xf)23#define MBOX_CHAN_PROPERTY 824 25static struct platform_device *rpi_hwmon;26static struct platform_device *rpi_clk;27 28struct rpi_firmware {29 struct mbox_client cl;30 struct mbox_chan *chan; /* The property channel. */31 struct completion c;32 u32 enabled;33 34 struct kref consumers;35};36 37static DEFINE_MUTEX(transaction_lock);38 39static void response_callback(struct mbox_client *cl, void *msg)40{41 struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);42 complete(&fw->c);43}44 45/*46 * Sends a request to the firmware through the BCM2835 mailbox driver,47 * and synchronously waits for the reply.48 */49static int50rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)51{52 u32 message = MBOX_MSG(chan, data);53 int ret;54 55 WARN_ON(data & 0xf);56 57 mutex_lock(&transaction_lock);58 reinit_completion(&fw->c);59 ret = mbox_send_message(fw->chan, &message);60 if (ret >= 0) {61 if (wait_for_completion_timeout(&fw->c, HZ)) {62 ret = 0;63 } else {64 ret = -ETIMEDOUT;65 }66 } else {67 dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);68 }69 mutex_unlock(&transaction_lock);70 71 return ret;72}73 74/**75 * rpi_firmware_property_list - Submit firmware property list76 * @fw: Pointer to firmware structure from rpi_firmware_get().77 * @data: Buffer holding tags.78 * @tag_size: Size of tags buffer.79 *80 * Submits a set of concatenated tags to the VPU firmware through the81 * mailbox property interface.82 *83 * The buffer header and the ending tag are added by this function and84 * don't need to be supplied, just the actual tags for your operation.85 * See struct rpi_firmware_property_tag_header for the per-tag86 * structure.87 */88int rpi_firmware_property_list(struct rpi_firmware *fw,89 void *data, size_t tag_size)90{91 size_t size = tag_size + 12;92 u32 *buf;93 dma_addr_t bus_addr;94 int ret;95 96 /* Packets are processed a dword at a time. */97 if (size & 3)98 return -EINVAL;99 100 buf = dma_alloc_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size),101 &bus_addr, GFP_ATOMIC);102 if (!buf)103 return -ENOMEM;104 105 /* The firmware will error out without parsing in this case. */106 WARN_ON(size >= 1024 * 1024);107 108 buf[0] = size;109 buf[1] = RPI_FIRMWARE_STATUS_REQUEST;110 memcpy(&buf[2], data, tag_size);111 buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;112 wmb();113 114 ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);115 116 rmb();117 memcpy(data, &buf[2], tag_size);118 if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {119 /*120 * The tag name here might not be the one causing the121 * error, if there were multiple tags in the request.122 * But single-tag is the most common, so go with it.123 */124 dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",125 buf[2], buf[1]);126 ret = -EINVAL;127 } else if (ret == -ETIMEDOUT) {128 WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]);129 }130 131 dma_free_coherent(fw->chan->mbox->dev, PAGE_ALIGN(size), buf, bus_addr);132 133 return ret;134}135EXPORT_SYMBOL_GPL(rpi_firmware_property_list);136 137/**138 * rpi_firmware_property - Submit single firmware property139 * @fw: Pointer to firmware structure from rpi_firmware_get().140 * @tag: One of enum_mbox_property_tag.141 * @tag_data: Tag data buffer.142 * @buf_size: Buffer size.143 *144 * Submits a single tag to the VPU firmware through the mailbox145 * property interface.146 *147 * This is a convenience wrapper around148 * rpi_firmware_property_list() to avoid some of the149 * boilerplate in property calls.150 */151int rpi_firmware_property(struct rpi_firmware *fw,152 u32 tag, void *tag_data, size_t buf_size)153{154 struct rpi_firmware_property_tag_header *header;155 int ret;156 157 /* Some mailboxes can use over 1k bytes. Rather than checking158 * size and using stack or kmalloc depending on requirements,159 * just use kmalloc. Mailboxes don't get called enough to worry160 * too much about the time taken in the allocation.161 */162 void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);163 164 if (!data)165 return -ENOMEM;166 167 header = data;168 header->tag = tag;169 header->buf_size = buf_size;170 header->req_resp_size = 0;171 memcpy(data + sizeof(*header), tag_data, buf_size);172 173 ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));174 175 memcpy(tag_data, data + sizeof(*header), buf_size);176 177 kfree(data);178 179 return ret;180}181EXPORT_SYMBOL_GPL(rpi_firmware_property);182 183static void184rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)185{186 time64_t date_and_time;187 u32 packet;188 int ret = rpi_firmware_property(fw,189 RPI_FIRMWARE_GET_FIRMWARE_REVISION,190 &packet, sizeof(packet));191 192 if (ret)193 return;194 195 /* This is not compatible with y2038 */196 date_and_time = packet;197 dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time);198}199 200static void201rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)202{203 u32 packet;204 int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,205 &packet, sizeof(packet));206 207 if (ret)208 return;209 210 rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",211 -1, NULL, 0);212}213 214static void rpi_register_clk_driver(struct device *dev)215{216 struct device_node *firmware;217 218 /*219 * Earlier DTs don't have a node for the firmware clocks but220 * rely on us creating a platform device by hand. If we do221 * have a node for the firmware clocks, just bail out here.222 */223 firmware = of_get_compatible_child(dev->of_node,224 "raspberrypi,firmware-clocks");225 if (firmware) {226 of_node_put(firmware);227 return;228 }229 230 rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",231 -1, NULL, 0);232}233 234unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id)235{236 struct rpi_firmware_clk_rate_request msg =237 RPI_FIRMWARE_CLK_RATE_REQUEST(id);238 int ret;239 240 ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE,241 &msg, sizeof(msg));242 if (ret)243 /*244 * If our firmware doesn't support that operation, or fails, we245 * assume the maximum clock rate is absolute maximum we can246 * store over our type.247 */248 return UINT_MAX;249 250 return le32_to_cpu(msg.rate);251}252EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate);253 254static void rpi_firmware_delete(struct kref *kref)255{256 struct rpi_firmware *fw = container_of(kref, struct rpi_firmware,257 consumers);258 259 mbox_free_channel(fw->chan);260 kfree(fw);261}262 263void rpi_firmware_put(struct rpi_firmware *fw)264{265 kref_put(&fw->consumers, rpi_firmware_delete);266}267EXPORT_SYMBOL_GPL(rpi_firmware_put);268 269static void devm_rpi_firmware_put(void *data)270{271 struct rpi_firmware *fw = data;272 273 rpi_firmware_put(fw);274}275 276static int rpi_firmware_probe(struct platform_device *pdev)277{278 struct device *dev = &pdev->dev;279 struct rpi_firmware *fw;280 281 /*282 * Memory will be freed by rpi_firmware_delete() once all users have283 * released their firmware handles. Don't use devm_kzalloc() here.284 */285 fw = kzalloc(sizeof(*fw), GFP_KERNEL);286 if (!fw)287 return -ENOMEM;288 289 fw->cl.dev = dev;290 fw->cl.rx_callback = response_callback;291 fw->cl.tx_block = true;292 293 fw->chan = mbox_request_channel(&fw->cl, 0);294 if (IS_ERR(fw->chan)) {295 int ret = PTR_ERR(fw->chan);296 kfree(fw);297 return dev_err_probe(dev, ret, "Failed to get mbox channel\n");298 }299 300 init_completion(&fw->c);301 kref_init(&fw->consumers);302 303 platform_set_drvdata(pdev, fw);304 305 rpi_firmware_print_firmware_revision(fw);306 rpi_register_hwmon_driver(dev, fw);307 rpi_register_clk_driver(dev);308 309 return 0;310}311 312static void rpi_firmware_shutdown(struct platform_device *pdev)313{314 struct rpi_firmware *fw = platform_get_drvdata(pdev);315 316 if (!fw)317 return;318 319 rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);320}321 322static void rpi_firmware_remove(struct platform_device *pdev)323{324 struct rpi_firmware *fw = platform_get_drvdata(pdev);325 326 platform_device_unregister(rpi_hwmon);327 rpi_hwmon = NULL;328 platform_device_unregister(rpi_clk);329 rpi_clk = NULL;330 331 rpi_firmware_put(fw);332}333 334static const struct of_device_id rpi_firmware_of_match[] = {335 { .compatible = "raspberrypi,bcm2835-firmware", },336 {},337};338MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);339 340struct device_node *rpi_firmware_find_node(void)341{342 return of_find_matching_node(NULL, rpi_firmware_of_match);343}344EXPORT_SYMBOL_GPL(rpi_firmware_find_node);345 346/**347 * rpi_firmware_get - Get pointer to rpi_firmware structure.348 * @firmware_node: Pointer to the firmware Device Tree node.349 *350 * The reference to rpi_firmware has to be released with rpi_firmware_put().351 *352 * Returns NULL is the firmware device is not ready.353 */354struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)355{356 struct platform_device *pdev = of_find_device_by_node(firmware_node);357 struct rpi_firmware *fw;358 359 if (!pdev)360 return NULL;361 362 fw = platform_get_drvdata(pdev);363 if (!fw)364 goto err_put_device;365 366 if (!kref_get_unless_zero(&fw->consumers))367 goto err_put_device;368 369 put_device(&pdev->dev);370 371 return fw;372 373err_put_device:374 put_device(&pdev->dev);375 return NULL;376}377EXPORT_SYMBOL_GPL(rpi_firmware_get);378 379/**380 * devm_rpi_firmware_get - Get pointer to rpi_firmware structure.381 * @dev: The firmware device structure382 * @firmware_node: Pointer to the firmware Device Tree node.383 *384 * Returns NULL is the firmware device is not ready.385 */386struct rpi_firmware *devm_rpi_firmware_get(struct device *dev,387 struct device_node *firmware_node)388{389 struct rpi_firmware *fw;390 391 fw = rpi_firmware_get(firmware_node);392 if (!fw)393 return NULL;394 395 if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw))396 return NULL;397 398 return fw;399}400EXPORT_SYMBOL_GPL(devm_rpi_firmware_get);401 402static struct platform_driver rpi_firmware_driver = {403 .driver = {404 .name = "raspberrypi-firmware",405 .of_match_table = rpi_firmware_of_match,406 },407 .probe = rpi_firmware_probe,408 .shutdown = rpi_firmware_shutdown,409 .remove_new = rpi_firmware_remove,410};411module_platform_driver(rpi_firmware_driver);412 413MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");414MODULE_DESCRIPTION("Raspberry Pi firmware driver");415MODULE_LICENSE("GPL v2");416