| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Defines interfaces for interacting with the Raspberry Pi firmware's |
| * property channel. |
| * |
| * Copyright © 2015 Broadcom |
| */ |
| |
| #include <linux/dma-mapping.h> |
| #include <linux/kref.h> |
| #include <linux/mailbox_client.h> |
| #include <linux/module.h> |
| #include <linux/of.h> |
| #include <linux/of_platform.h> |
| #include <linux/platform_device.h> |
| #include <linux/slab.h> |
| #include <soc/bcm2835/raspberrypi-firmware.h> |
| |
| #define MBOX_MSG(chan, data28) (((data28) & ~0xf) | ((chan) & 0xf)) |
| #define MBOX_CHAN(msg) ((msg) & 0xf) |
| #define MBOX_DATA28(msg) ((msg) & ~0xf) |
| #define MBOX_CHAN_PROPERTY 8 |
| |
| static struct platform_device *rpi_hwmon; |
| static struct platform_device *rpi_clk; |
| |
| struct rpi_firmware { |
| struct mbox_client cl; |
| struct mbox_chan *chan; /* The property channel. */ |
| struct completion c; |
| u32 enabled; |
| |
| struct kref consumers; |
| }; |
| |
| static DEFINE_MUTEX(transaction_lock); |
| |
| static void response_callback(struct mbox_client *cl, void *msg) |
| { |
| struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl); |
| complete(&fw->c); |
| } |
| |
| /* |
| * Sends a request to the firmware through the BCM2835 mailbox driver, |
| * and synchronously waits for the reply. |
| */ |
| static int |
| rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data) |
| { |
| u32 message = MBOX_MSG(chan, data); |
| int ret; |
| |
| WARN_ON(data & 0xf); |
| |
| mutex_lock(&transaction_lock); |
| reinit_completion(&fw->c); |
| ret = mbox_send_message(fw->chan, &message); |
| if (ret >= 0) { |
| if (wait_for_completion_timeout(&fw->c, HZ)) { |
| ret = 0; |
| } else { |
| ret = -ETIMEDOUT; |
| WARN_ONCE(1, "Firmware transaction timeout"); |
| } |
| } else { |
| dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret); |
| } |
| mutex_unlock(&transaction_lock); |
| |
| return ret; |
| } |
| |
| /** |
| * rpi_firmware_property_list - Submit firmware property list |
| * @fw: Pointer to firmware structure from rpi_firmware_get(). |
| * @data: Buffer holding tags. |
| * @tag_size: Size of tags buffer. |
| * |
| * Submits a set of concatenated tags to the VPU firmware through the |
| * mailbox property interface. |
| * |
| * The buffer header and the ending tag are added by this function and |
| * don't need to be supplied, just the actual tags for your operation. |
| * See struct rpi_firmware_property_tag_header for the per-tag |
| * structure. |
| */ |
| int rpi_firmware_property_list(struct rpi_firmware *fw, |
| void *data, size_t tag_size) |
| { |
| size_t size = tag_size + 12; |
| u32 *buf; |
| dma_addr_t bus_addr; |
| int ret; |
| |
| /* Packets are processed a dword at a time. */ |
| if (size & 3) |
| return -EINVAL; |
| |
| buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr, |
| GFP_ATOMIC); |
| if (!buf) |
| return -ENOMEM; |
| |
| /* The firmware will error out without parsing in this case. */ |
| WARN_ON(size >= 1024 * 1024); |
| |
| buf[0] = size; |
| buf[1] = RPI_FIRMWARE_STATUS_REQUEST; |
| memcpy(&buf[2], data, tag_size); |
| buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END; |
| wmb(); |
| |
| ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr); |
| |
| rmb(); |
| memcpy(data, &buf[2], tag_size); |
| if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) { |
| /* |
| * The tag name here might not be the one causing the |
| * error, if there were multiple tags in the request. |
| * But single-tag is the most common, so go with it. |
| */ |
| dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n", |
| buf[2], buf[1]); |
| ret = -EINVAL; |
| } |
| |
| dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_property_list); |
| |
| /** |
| * rpi_firmware_property - Submit single firmware property |
| * @fw: Pointer to firmware structure from rpi_firmware_get(). |
| * @tag: One of enum_mbox_property_tag. |
| * @tag_data: Tag data buffer. |
| * @buf_size: Buffer size. |
| * |
| * Submits a single tag to the VPU firmware through the mailbox |
| * property interface. |
| * |
| * This is a convenience wrapper around |
| * rpi_firmware_property_list() to avoid some of the |
| * boilerplate in property calls. |
| */ |
| int rpi_firmware_property(struct rpi_firmware *fw, |
| u32 tag, void *tag_data, size_t buf_size) |
| { |
| struct rpi_firmware_property_tag_header *header; |
| int ret; |
| |
| /* Some mailboxes can use over 1k bytes. Rather than checking |
| * size and using stack or kmalloc depending on requirements, |
| * just use kmalloc. Mailboxes don't get called enough to worry |
| * too much about the time taken in the allocation. |
| */ |
| void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL); |
| |
| if (!data) |
| return -ENOMEM; |
| |
| header = data; |
| header->tag = tag; |
| header->buf_size = buf_size; |
| header->req_resp_size = 0; |
| memcpy(data + sizeof(*header), tag_data, buf_size); |
| |
| ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header)); |
| |
| memcpy(tag_data, data + sizeof(*header), buf_size); |
| |
| kfree(data); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_property); |
| |
| static void |
| rpi_firmware_print_firmware_revision(struct rpi_firmware *fw) |
| { |
| time64_t date_and_time; |
| u32 packet; |
| int ret = rpi_firmware_property(fw, |
| RPI_FIRMWARE_GET_FIRMWARE_REVISION, |
| &packet, sizeof(packet)); |
| |
| if (ret) |
| return; |
| |
| /* This is not compatible with y2038 */ |
| date_and_time = packet; |
| dev_info(fw->cl.dev, "Attached to firmware from %ptT\n", &date_and_time); |
| } |
| |
| static void |
| rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw) |
| { |
| u32 packet; |
| int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED, |
| &packet, sizeof(packet)); |
| |
| if (ret) |
| return; |
| |
| rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon", |
| -1, NULL, 0); |
| } |
| |
| static void rpi_register_clk_driver(struct device *dev) |
| { |
| struct device_node *firmware; |
| |
| /* |
| * Earlier DTs don't have a node for the firmware clocks but |
| * rely on us creating a platform device by hand. If we do |
| * have a node for the firmware clocks, just bail out here. |
| */ |
| firmware = of_get_compatible_child(dev->of_node, |
| "raspberrypi,firmware-clocks"); |
| if (firmware) { |
| of_node_put(firmware); |
| return; |
| } |
| |
| rpi_clk = platform_device_register_data(dev, "raspberrypi-clk", |
| -1, NULL, 0); |
| } |
| |
| unsigned int rpi_firmware_clk_get_max_rate(struct rpi_firmware *fw, unsigned int id) |
| { |
| struct rpi_firmware_clk_rate_request msg = |
| RPI_FIRMWARE_CLK_RATE_REQUEST(id); |
| int ret; |
| |
| ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_MAX_CLOCK_RATE, |
| &msg, sizeof(msg)); |
| if (ret) |
| /* |
| * If our firmware doesn't support that operation, or fails, we |
| * assume the maximum clock rate is absolute maximum we can |
| * store over our type. |
| */ |
| return UINT_MAX; |
| |
| return le32_to_cpu(msg.rate); |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_clk_get_max_rate); |
| |
| static void rpi_firmware_delete(struct kref *kref) |
| { |
| struct rpi_firmware *fw = container_of(kref, struct rpi_firmware, |
| consumers); |
| |
| mbox_free_channel(fw->chan); |
| kfree(fw); |
| } |
| |
| void rpi_firmware_put(struct rpi_firmware *fw) |
| { |
| kref_put(&fw->consumers, rpi_firmware_delete); |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_put); |
| |
| static void devm_rpi_firmware_put(void *data) |
| { |
| struct rpi_firmware *fw = data; |
| |
| rpi_firmware_put(fw); |
| } |
| |
| static int rpi_firmware_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct rpi_firmware *fw; |
| |
| /* |
| * Memory will be freed by rpi_firmware_delete() once all users have |
| * released their firmware handles. Don't use devm_kzalloc() here. |
| */ |
| fw = kzalloc(sizeof(*fw), GFP_KERNEL); |
| if (!fw) |
| return -ENOMEM; |
| |
| fw->cl.dev = dev; |
| fw->cl.rx_callback = response_callback; |
| fw->cl.tx_block = true; |
| |
| fw->chan = mbox_request_channel(&fw->cl, 0); |
| if (IS_ERR(fw->chan)) { |
| int ret = PTR_ERR(fw->chan); |
| kfree(fw); |
| return dev_err_probe(dev, ret, "Failed to get mbox channel\n"); |
| } |
| |
| init_completion(&fw->c); |
| kref_init(&fw->consumers); |
| |
| platform_set_drvdata(pdev, fw); |
| |
| rpi_firmware_print_firmware_revision(fw); |
| rpi_register_hwmon_driver(dev, fw); |
| rpi_register_clk_driver(dev); |
| |
| return 0; |
| } |
| |
| static void rpi_firmware_shutdown(struct platform_device *pdev) |
| { |
| struct rpi_firmware *fw = platform_get_drvdata(pdev); |
| |
| if (!fw) |
| return; |
| |
| rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0); |
| } |
| |
| static int rpi_firmware_remove(struct platform_device *pdev) |
| { |
| struct rpi_firmware *fw = platform_get_drvdata(pdev); |
| |
| platform_device_unregister(rpi_hwmon); |
| rpi_hwmon = NULL; |
| platform_device_unregister(rpi_clk); |
| rpi_clk = NULL; |
| |
| rpi_firmware_put(fw); |
| |
| return 0; |
| } |
| |
| static const struct of_device_id rpi_firmware_of_match[] = { |
| { .compatible = "raspberrypi,bcm2835-firmware", }, |
| {}, |
| }; |
| MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); |
| |
| struct device_node *rpi_firmware_find_node(void) |
| { |
| return of_find_matching_node(NULL, rpi_firmware_of_match); |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_find_node); |
| |
| /** |
| * rpi_firmware_get - Get pointer to rpi_firmware structure. |
| * @firmware_node: Pointer to the firmware Device Tree node. |
| * |
| * The reference to rpi_firmware has to be released with rpi_firmware_put(). |
| * |
| * Returns NULL is the firmware device is not ready. |
| */ |
| struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node) |
| { |
| struct platform_device *pdev = of_find_device_by_node(firmware_node); |
| struct rpi_firmware *fw; |
| |
| if (!pdev) |
| return NULL; |
| |
| fw = platform_get_drvdata(pdev); |
| if (!fw) |
| goto err_put_device; |
| |
| if (!kref_get_unless_zero(&fw->consumers)) |
| goto err_put_device; |
| |
| put_device(&pdev->dev); |
| |
| return fw; |
| |
| err_put_device: |
| put_device(&pdev->dev); |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(rpi_firmware_get); |
| |
| /** |
| * devm_rpi_firmware_get - Get pointer to rpi_firmware structure. |
| * @firmware_node: Pointer to the firmware Device Tree node. |
| * |
| * Returns NULL is the firmware device is not ready. |
| */ |
| struct rpi_firmware *devm_rpi_firmware_get(struct device *dev, |
| struct device_node *firmware_node) |
| { |
| struct rpi_firmware *fw; |
| |
| fw = rpi_firmware_get(firmware_node); |
| if (!fw) |
| return NULL; |
| |
| if (devm_add_action_or_reset(dev, devm_rpi_firmware_put, fw)) |
| return NULL; |
| |
| return fw; |
| } |
| EXPORT_SYMBOL_GPL(devm_rpi_firmware_get); |
| |
| static struct platform_driver rpi_firmware_driver = { |
| .driver = { |
| .name = "raspberrypi-firmware", |
| .of_match_table = rpi_firmware_of_match, |
| }, |
| .probe = rpi_firmware_probe, |
| .shutdown = rpi_firmware_shutdown, |
| .remove = rpi_firmware_remove, |
| }; |
| module_platform_driver(rpi_firmware_driver); |
| |
| MODULE_AUTHOR("Eric Anholt <eric@anholt.net>"); |
| MODULE_DESCRIPTION("Raspberry Pi firmware driver"); |
| MODULE_LICENSE("GPL v2"); |