1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Defines interfaces for interacting wtih the Raspberry Pi firmware's
  4 * property channel.
  5 *
  6 * Copyright © 2015 Broadcom
  7 */
  8
  9#include <linux/dma-mapping.h>
 10#include <linux/mailbox_client.h>
 11#include <linux/module.h>
 12#include <linux/of_platform.h>
 13#include <linux/platform_device.h>
 14#include <linux/slab.h>
 15#include <soc/bcm2835/raspberrypi-firmware.h>
 16
 17#define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
 18#define MBOX_CHAN(msg)			((msg) & 0xf)
 19#define MBOX_DATA28(msg)		((msg) & ~0xf)
 20#define MBOX_CHAN_PROPERTY		8
 21
 22static struct platform_device *rpi_hwmon;
 23static struct platform_device *rpi_clk;
 24
 25struct rpi_firmware {
 26	struct mbox_client cl;
 27	struct mbox_chan *chan; /* The property channel. */
 28	struct completion c;
 29	u32 enabled;
 30};
 31
 32static DEFINE_MUTEX(transaction_lock);
 33
 34static void response_callback(struct mbox_client *cl, void *msg)
 35{
 36	struct rpi_firmware *fw = container_of(cl, struct rpi_firmware, cl);
 37	complete(&fw->c);
 38}
 39
 40/*
 41 * Sends a request to the firmware through the BCM2835 mailbox driver,
 42 * and synchronously waits for the reply.
 43 */
 44static int
 45rpi_firmware_transaction(struct rpi_firmware *fw, u32 chan, u32 data)
 46{
 47	u32 message = MBOX_MSG(chan, data);
 48	int ret;
 49
 50	WARN_ON(data & 0xf);
 51
 52	mutex_lock(&transaction_lock);
 53	reinit_completion(&fw->c);
 54	ret = mbox_send_message(fw->chan, &message);
 55	if (ret >= 0) {
 56		if (wait_for_completion_timeout(&fw->c, HZ)) {
 57			ret = 0;
 58		} else {
 59			ret = -ETIMEDOUT;
 60			WARN_ONCE(1, "Firmware transaction timeout");
 61		}
 62	} else {
 63		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
 64	}
 65	mutex_unlock(&transaction_lock);
 66
 67	return ret;
 68}
 69
 70/**
 71 * rpi_firmware_property_list - Submit firmware property list
 72 * @fw:		Pointer to firmware structure from rpi_firmware_get().
 73 * @data:	Buffer holding tags.
 74 * @tag_size:	Size of tags buffer.
 75 *
 76 * Submits a set of concatenated tags to the VPU firmware through the
 77 * mailbox property interface.
 78 *
 79 * The buffer header and the ending tag are added by this function and
 80 * don't need to be supplied, just the actual tags for your operation.
 81 * See struct rpi_firmware_property_tag_header for the per-tag
 82 * structure.
 83 */
 84int rpi_firmware_property_list(struct rpi_firmware *fw,
 85			       void *data, size_t tag_size)
 86{
 87	size_t size = tag_size + 12;
 88	u32 *buf;
 89	dma_addr_t bus_addr;
 90	int ret;
 91
 92	/* Packets are processed a dword at a time. */
 93	if (size & 3)
 94		return -EINVAL;
 95
 96	buf = dma_alloc_coherent(fw->cl.dev, PAGE_ALIGN(size), &bus_addr,
 97				 GFP_ATOMIC);
 98	if (!buf)
 99		return -ENOMEM;
100
101	/* The firmware will error out without parsing in this case. */
102	WARN_ON(size >= 1024 * 1024);
103
104	buf[0] = size;
105	buf[1] = RPI_FIRMWARE_STATUS_REQUEST;
106	memcpy(&buf[2], data, tag_size);
107	buf[size / 4 - 1] = RPI_FIRMWARE_PROPERTY_END;
108	wmb();
109
110	ret = rpi_firmware_transaction(fw, MBOX_CHAN_PROPERTY, bus_addr);
111
112	rmb();
113	memcpy(data, &buf[2], tag_size);
114	if (ret == 0 && buf[1] != RPI_FIRMWARE_STATUS_SUCCESS) {
115		/*
116		 * The tag name here might not be the one causing the
117		 * error, if there were multiple tags in the request.
118		 * But single-tag is the most common, so go with it.
119		 */
120		dev_err(fw->cl.dev, "Request 0x%08x returned status 0x%08x\n",
121			buf[2], buf[1]);
122		ret = -EINVAL;
123	}
124
125	dma_free_coherent(fw->cl.dev, PAGE_ALIGN(size), buf, bus_addr);
126
127	return ret;
128}
129EXPORT_SYMBOL_GPL(rpi_firmware_property_list);
130
131/**
132 * rpi_firmware_property - Submit single firmware property
133 * @fw:		Pointer to firmware structure from rpi_firmware_get().
134 * @tag:	One of enum_mbox_property_tag.
135 * @tag_data:	Tag data buffer.
136 * @buf_size:	Buffer size.
137 *
138 * Submits a single tag to the VPU firmware through the mailbox
139 * property interface.
140 *
141 * This is a convenience wrapper around
142 * rpi_firmware_property_list() to avoid some of the
143 * boilerplate in property calls.
144 */
145int rpi_firmware_property(struct rpi_firmware *fw,
146			  u32 tag, void *tag_data, size_t buf_size)
147{
148	struct rpi_firmware_property_tag_header *header;
149	int ret;
150
151	/* Some mailboxes can use over 1k bytes. Rather than checking
152	 * size and using stack or kmalloc depending on requirements,
153	 * just use kmalloc. Mailboxes don't get called enough to worry
154	 * too much about the time taken in the allocation.
155	 */
156	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
157
158	if (!data)
159		return -ENOMEM;
160
161	header = data;
162	header->tag = tag;
163	header->buf_size = buf_size;
164	header->req_resp_size = 0;
165	memcpy(data + sizeof(*header), tag_data, buf_size);
166
167	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
168
169	memcpy(tag_data, data + sizeof(*header), buf_size);
170
171	kfree(data);
172
173	return ret;
174}
175EXPORT_SYMBOL_GPL(rpi_firmware_property);
176
177static void
178rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
179{
180	u32 packet;
181	int ret = rpi_firmware_property(fw,
182					RPI_FIRMWARE_GET_FIRMWARE_REVISION,
183					&packet, sizeof(packet));
184
185	if (ret == 0) {
186		struct tm tm;
187
188		time64_to_tm(packet, 0, &tm);
189
190		dev_info(fw->cl.dev,
191			 "Attached to firmware from %04ld-%02d-%02d %02d:%02d\n",
192			 tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
193			 tm.tm_hour, tm.tm_min);
194	}
195}
196
197static void
198rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
199{
200	u32 packet;
201	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
202					&packet, sizeof(packet));
203
204	if (ret)
205		return;
206
207	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
208						  -1, NULL, 0);
209}
210
211static void rpi_register_clk_driver(struct device *dev)
212{
213	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
214						-1, NULL, 0);
215}
216
217static int rpi_firmware_probe(struct platform_device *pdev)
218{
219	struct device *dev = &pdev->dev;
220	struct rpi_firmware *fw;
221
222	fw = devm_kzalloc(dev, sizeof(*fw), GFP_KERNEL);
223	if (!fw)
224		return -ENOMEM;
225
226	fw->cl.dev = dev;
227	fw->cl.rx_callback = response_callback;
228	fw->cl.tx_block = true;
229
230	fw->chan = mbox_request_channel(&fw->cl, 0);
231	if (IS_ERR(fw->chan)) {
232		int ret = PTR_ERR(fw->chan);
233		if (ret != -EPROBE_DEFER)
234			dev_err(dev, "Failed to get mbox channel: %d\n", ret);
235		return ret;
236	}
237
238	init_completion(&fw->c);
239
240	platform_set_drvdata(pdev, fw);
241
242	rpi_firmware_print_firmware_revision(fw);
243	rpi_register_hwmon_driver(dev, fw);
244	rpi_register_clk_driver(dev);
245
246	return 0;
247}
248
249static void rpi_firmware_shutdown(struct platform_device *pdev)
250{
251	struct rpi_firmware *fw = platform_get_drvdata(pdev);
252
253	if (!fw)
254		return;
255
256	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
257}
258
259static int rpi_firmware_remove(struct platform_device *pdev)
260{
261	struct rpi_firmware *fw = platform_get_drvdata(pdev);
262
263	platform_device_unregister(rpi_hwmon);
264	rpi_hwmon = NULL;
265	platform_device_unregister(rpi_clk);
266	rpi_clk = NULL;
267	mbox_free_channel(fw->chan);
268
269	return 0;
270}
271
272/**
273 * rpi_firmware_get - Get pointer to rpi_firmware structure.
274 * @firmware_node:    Pointer to the firmware Device Tree node.
275 *
276 * Returns NULL is the firmware device is not ready.
277 */
278struct rpi_firmware *rpi_firmware_get(struct device_node *firmware_node)
279{
280	struct platform_device *pdev = of_find_device_by_node(firmware_node);
281
282	if (!pdev)
283		return NULL;
284
285	return platform_get_drvdata(pdev);
286}
287EXPORT_SYMBOL_GPL(rpi_firmware_get);
288
289static const struct of_device_id rpi_firmware_of_match[] = {
290	{ .compatible = "raspberrypi,bcm2835-firmware", },
291	{},
292};
293MODULE_DEVICE_TABLE(of, rpi_firmware_of_match);
294
295static struct platform_driver rpi_firmware_driver = {
296	.driver = {
297		.name = "raspberrypi-firmware",
298		.of_match_table = rpi_firmware_of_match,
299	},
300	.probe		= rpi_firmware_probe,
301	.shutdown	= rpi_firmware_shutdown,
302	.remove		= rpi_firmware_remove,
303};
304module_platform_driver(rpi_firmware_driver);
305
306MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
307MODULE_DESCRIPTION("Raspberry Pi firmware driver");
308MODULE_LICENSE("GPL v2");