/* * Defines interfaces for interacting wtih the Raspberry Pi firmware's * property channel. * * Copyright © 2015 Broadcom * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/dma-mapping.h>#include <linux/mailbox_client.h>#include <linux/module.h>#include <linux/of_platform.h>#include <linux/platform_device.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 struct rpi_firmware {	struct mbox_client cl;	struct mbox_chan *chan; /* The property channel. */	struct completion c;	u32 enabled;}; 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) {		wait_for_completion(&fw->c);		ret = 0;	} 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){	/* Single tags are very small (generally 8 bytes), so the	 * stack should be safe.	 */	u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];	struct rpi_firmware_property_tag_header *header =		(struct rpi_firmware_property_tag_header *)data;	int ret; 	header->tag = tag;	header->buf_size = buf_size;	header->req_resp_size = 0;	memcpy(data + sizeof(struct rpi_firmware_property_tag_header),	       tag_data, buf_size); 	ret = rpi_firmware_property_list(fw, &data, sizeof(data));	memcpy(tag_data,	       data + sizeof(struct rpi_firmware_property_tag_header),	       buf_size); 	return ret;}EXPORT_SYMBOL_GPL(rpi_firmware_property); static voidrpi_firmware_print_firmware_revision(struct rpi_firmware *fw){	u32 packet;	int ret = rpi_firmware_property(fw,					RPI_FIRMWARE_GET_FIRMWARE_REVISION,					&packet, sizeof(packet)); 	if (ret == 0) {		struct tm tm; 		time_to_tm(packet, 0, &tm); 		dev_info(fw->cl.dev,			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,			 tm.tm_hour, tm.tm_min);	}} static int rpi_firmware_probe(struct platform_device *pdev){	struct device *dev = &pdev->dev;	struct rpi_firmware *fw; 	fw = devm_kzalloc(dev, 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);		if (ret != -EPROBE_DEFER)			dev_err(dev, "Failed to get mbox channel: %d\n", ret);		return ret;	} 	init_completion(&fw->c); 	platform_set_drvdata(pdev, fw); 	rpi_firmware_print_firmware_revision(fw); 	return 0;} static int rpi_firmware_remove(struct platform_device *pdev){	struct rpi_firmware *fw = platform_get_drvdata(pdev); 	mbox_free_channel(fw->chan); 	return 0;} /** * 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 *rpi_firmware_get(struct device_node *firmware_node){	struct platform_device *pdev = of_find_device_by_node(firmware_node); 	if (!pdev)		return NULL; 	return platform_get_drvdata(pdev);}EXPORT_SYMBOL_GPL(rpi_firmware_get); static const struct of_device_id rpi_firmware_of_match[] = {	{ .compatible = "raspberrypi,bcm2835-firmware", },	{},};MODULE_DEVICE_TABLE(of, rpi_firmware_of_match); static struct platform_driver rpi_firmware_driver = {	.driver = {		.name = "raspberrypi-firmware",		.of_match_table = rpi_firmware_of_match,	},	.probe		= rpi_firmware_probe,	.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");