// 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/mailbox_controller.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 intrpi_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;		}	} 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->chan->mbox->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;	} else if (ret == -ETIMEDOUT) {		WARN_ONCE(1, "Firmware transaction 0x%08x timeout", buf[2]);	} 	dma_free_coherent(fw->chan->mbox->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 voidrpi_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 voidrpi_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_obj(*fw);	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 void 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);} 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. * @dev:              The firmware device 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");