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
 24struct rpi_firmware {
 25	struct mbox_client cl;
 26	struct mbox_chan *chan; /* The property channel. */
 27	struct completion c;
 28	u32 enabled;
 29};
 30
 31static DEFINE_MUTEX(transaction_lock);
 32
 33static void response_callback(struct mbox_client *cl, void *msg)
 34{
 35	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
 36	complete(&fw->c);
 37}
 38
 39/*
 40 * Sends a request to the firmware through the BCM2835 mailbox driver,
 41 * and synchronously waits for the reply.
 42 */
 43static int
 44rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
 45{
 46	u32 message = MBOX_MSG(chan, data);
 47	int ret;
 48
 49	WARN_ON(data & 0xf);
 50
 51	mutex_lock(&transaction_lock);
 52	reinit_completion(&fw->c);
 53	ret = mbox_send_message(fw->chan, &message);
 54	if (ret >= 0) {
 55		wait_for_completion(&fw->c);
 56		ret = 0;
 57	} else {
 58		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
 59	}
 60	mutex_unlock(&transaction_lock);
 61
 62	return ret;
 63}
 64
 65/**
 66 * rpi_firmware_property_list - Submit firmware property list
 67 * @fw:		Pointer to firmware structure from rpi_firmware_get().
 68 * @data:	Buffer holding tags.
 69 * @tag_size:	Size of tags buffer.
 70 *
 71 * Submits a set of concatenated tags to the VPU firmware through the
 72 * mailbox property interface.
 73 *
 74 * The buffer header and the ending tag are added by this function and
 75 * don't need to be supplied, just the actual tags for your operation.
 76 * See struct rpi_firmware_property_tag_header for the per-tag
 77 * structure.
 78 */
 79int rpi_firmware_property_list(struct rpi_firmware *fw,
 80			       void *data, size_t tag_size)
 81{
 82	size_t size = tag_size + 12;
 83	u32 *buf;
 84	dma_addr_t bus_addr;
 85	int ret;
 86
 87	/* Packets are processed a dword at a time. */
 88	if (size & 3)
 89		return -EINVAL;
 90
 91	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
 92				 GFP_ATOMIC);
 93	if (!buf)
 94		return -ENOMEM;
 95
 96	/* The firmware will error out without parsing in this case. */
 97	WARN_ON(size >= 1024 * 1024);
 98
 99	buf[0] = size;
100	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
101	memcpy(&buf[2], data, tag_size);
102	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
103	wmb();
104
105	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
106
107	rmb();
108	memcpy(data, &buf[2], tag_size);
109	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
110		/*
111		 * The tag name here might not be the one causing the
112		 * error, if there were multiple tags in the request.
113		 * But single-tag is the most common, so go with it.
114		 */
115		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
116			buf[2], buf[1]);
117		ret = -EINVAL;
118	}
119
120	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
121
122	return ret;
123}
124EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
125
126/**
127 * rpi_firmware_property - Submit single firmware property
128 * @fw:		Pointer to firmware structure from rpi_firmware_get().
129 * @tag:	One of enum_mbox_property_tag.
130 * @tag_data:	Tag data buffer.
131 * @buf_size:	Buffer size.
132 *
133 * Submits a single tag to the VPU firmware through the mailbox
134 * property interface.
135 *
136 * This is a convenience wrapper around
137 * rpi_firmware_property_list() to avoid some of the
138 * boilerplate in property calls.
139 */
140int rpi_firmware_property(struct rpi_firmware *fw,
141			  u32 tag, void *tag_data, size_t buf_size)
142{
143	/* Single tags are very small (generally 8 bytes), so the
144	 * stack should be safe.
145	 */
146	u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
147	struct rpi_firmware_property_tag_header *header =
148		(struct rpi_firmware_property_tag_header *)data;
149	int ret;
150
151	header->tag = tag;
152	header->buf_size = buf_size;
153	header->req_resp_size = 0;
154	memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
155	       tag_data, buf_size);
156
157	ret = rpi_firmware_property_list(fw, &data, sizeof(data));
158	memcpy(tag_data,
159	       data + sizeof(struct rpi_firmware_property_tag_header),
160	       buf_size);
161
162	return ret;
163}
164EXPORT_SYMBOL_GPL(rpi_firmware_property);
165
166static void
167rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
168{
169	u32 packet;
170	int ret = rpi_firmware_property(fw,
171					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
172					&packet, sizeof(packet));
173
174	if (ret == 0) {
175		struct tm tm;
176
177		time_to_tm(packet, 0, &tm);
178
179		dev_info(fw->cl.dev,
180			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
181			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
182			 tm.tm_hour, tm.tm_min);
183	}
184}
185
186static int rpi_firmware_probe(struct platform_device *pdev)
187{
188	struct device *dev = &pdev->dev;
189	struct rpi_firmware *fw;
190
191	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
192	if (!fw)
193		return -ENOMEM;
194
195	fw->cl.dev = dev;
196	fw->cl.rx_callback = response_callback;
197	fw->cl.tx_block = true;
198
199	fw->chan = mbox_request_channel(&fw->cl, 0);
200	if (IS_ERR(fw->chan)) {
201		int ret = PTR_ERR(fw->chan);
202		if (ret != -EPROBE_DEFER)
203			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
204		return ret;
205	}
206
207	init_completion(&fw->c);
208
209	platform_set_drvdata(pdev, fw);
210
211	rpi_firmware_print_firmware_revision(fw);
212
213	return 0;
214}
215
216static int rpi_firmware_remove(struct platform_device *pdev)
217{
218	struct rpi_firmware *fw = platform_get_drvdata(pdev);
219
220	mbox_free_channel(fw->chan);
221
222	return 0;
223}
224
225/**
226 * rpi_firmware_get - Get pointer to rpi_firmware structure.
227 * @firmware_node:    Pointer to the firmware Device Tree node.
228 *
229 * Returns NULL is the firmware device is not ready.
230 */
231struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
232{
233	struct platform_device *pdev = of_find_device_by_node(firmware_node);
234
235	if (!pdev)
236		return NULL;
237
238	return platform_get_drvdata(pdev);
239}
240EXPORT_SYMBOL_GPL(rpi_firmware_get);
241
242static const struct of_device_id rpi_firmware_of_match[] = {
243	{ .compatible = "raspberrypi,bcm2835-firmware", },
244	{},
245};
246MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
247
248static struct platform_driver rpi_firmware_driver = {
249	.driver = {
250		.name = "raspberrypi-firmware",
251		.of_match_table = rpi_firmware_of_match,
252	},
253	.probe		= rpi_firmware_probe,
254	.remove		= rpi_firmware_remove,
255};
256module_platform_driver(rpi_firmware_driver);
257
258MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
259MODULE_DESCRIPTION("Raspberry Pi firmware driver");
260MODULE_LICENSE("GPL v2");