1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2016-2017, Linaro Ltd
4  */
5 
6 #include <linux/idr.h>
7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/list.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 #include <linux/rpmsg.h>
18 #include <linux/slab.h>
19 #include <linux/workqueue.h>
20 #include <linux/mailbox_client.h>
21 
22 #include "rpmsg_internal.h"
23 #include "qcom_glink_native.h"
24 
25 #define RPM_TOC_SIZE		256
26 #define RPM_TOC_MAGIC		0x67727430 /* grt0 */
27 #define RPM_TOC_MAX_ENTRIES	((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
28 				 sizeof(struct rpm_toc_entry))
29 
30 #define RPM_TX_FIFO_ID		0x61703272 /* ap2r */
31 #define RPM_RX_FIFO_ID		0x72326170 /* r2ap */
32 
33 #define to_rpm_pipe(p) container_of(p, struct glink_rpm_pipe, native)
34 
35 struct rpm_toc_entry {
36 	__le32 id;
37 	__le32 offset;
38 	__le32 size;
39 } __packed;
40 
41 struct rpm_toc {
42 	__le32 magic;
43 	__le32 count;
44 
45 	struct rpm_toc_entry entries[];
46 } __packed;
47 
48 struct glink_rpm_pipe {
49 	struct qcom_glink_pipe native;
50 
51 	void __iomem *tail;
52 	void __iomem *head;
53 
54 	void __iomem *fifo;
55 };
56 
57 struct glink_rpm {
58 	struct qcom_glink *glink;
59 
60 	int irq;
61 
62 	struct mbox_client mbox_client;
63 	struct mbox_chan *mbox_chan;
64 
65 	struct glink_rpm_pipe rx_pipe;
66 	struct glink_rpm_pipe tx_pipe;
67 };
68 
69 static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
70 {
71 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
72 	unsigned int head;
73 	unsigned int tail;
74 
75 	head = readl(pipe->head);
76 	tail = readl(pipe->tail);
77 
78 	if (head < tail)
79 		return pipe->native.length - tail + head;
80 	else
81 		return head - tail;
82 }
83 
84 static void glink_rpm_rx_peek(struct qcom_glink_pipe *glink_pipe,
85 			      void *data, unsigned int offset, size_t count)
86 {
87 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
88 	unsigned int tail;
89 	size_t len;
90 
91 	tail = readl(pipe->tail);
92 	tail += offset;
93 	if (tail >= pipe->native.length)
94 		tail -= pipe->native.length;
95 
96 	len = min_t(size_t, count, pipe->native.length - tail);
97 	if (len) {
98 		__ioread32_copy(data, pipe->fifo + tail,
99 				len / sizeof(u32));
100 	}
101 
102 	if (len != count) {
103 		__ioread32_copy(data + len, pipe->fifo,
104 				(count - len) / sizeof(u32));
105 	}
106 }
107 
108 static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
109 				 size_t count)
110 {
111 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
112 	unsigned int tail;
113 
114 	tail = readl(pipe->tail);
115 
116 	tail += count;
117 	if (tail >= pipe->native.length)
118 		tail -= pipe->native.length;
119 
120 	writel(tail, pipe->tail);
121 }
122 
123 static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
124 {
125 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
126 	unsigned int head;
127 	unsigned int tail;
128 
129 	head = readl(pipe->head);
130 	tail = readl(pipe->tail);
131 
132 	if (tail <= head)
133 		return pipe->native.length - head + tail;
134 	else
135 		return tail - head;
136 }
137 
138 static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
139 					   unsigned int head,
140 					   const void *data, size_t count)
141 {
142 	size_t len;
143 
144 	len = min_t(size_t, count, pipe->native.length - head);
145 	if (len) {
146 		__iowrite32_copy(pipe->fifo + head, data,
147 				 len / sizeof(u32));
148 	}
149 
150 	if (len != count) {
151 		__iowrite32_copy(pipe->fifo, data + len,
152 				 (count - len) / sizeof(u32));
153 	}
154 
155 	head += count;
156 	if (head >= pipe->native.length)
157 		head -= pipe->native.length;
158 
159 	return head;
160 }
161 
162 static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
163 			       const void *hdr, size_t hlen,
164 			       const void *data, size_t dlen)
165 {
166 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
167 	size_t tlen = hlen + dlen;
168 	size_t aligned_dlen;
169 	unsigned int head;
170 	char padding[8] = {0};
171 	size_t pad;
172 
173 	/* Header length comes from glink native and is always 4 byte aligned */
174 	if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
175 		return;
176 
177 	/*
178 	 * Move the unaligned tail of the message to the padding chunk, to
179 	 * ensure word aligned accesses
180 	 */
181 	aligned_dlen = ALIGN_DOWN(dlen, 4);
182 	if (aligned_dlen != dlen)
183 		memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
184 
185 	head = readl(pipe->head);
186 	head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
187 	head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
188 
189 	pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
190 	if (pad)
191 		head = glink_rpm_tx_write_one(pipe, head, padding, pad);
192 	writel(head, pipe->head);
193 }
194 
195 static void glink_rpm_tx_kick(struct qcom_glink_pipe *glink_pipe)
196 {
197 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
198 	struct glink_rpm *rpm = container_of(pipe, struct glink_rpm, tx_pipe);
199 
200 	mbox_send_message(rpm->mbox_chan, NULL);
201 	mbox_client_txdone(rpm->mbox_chan, 0);
202 }
203 
204 static irqreturn_t qcom_glink_rpm_intr(int irq, void *data)
205 {
206 	struct glink_rpm *rpm = data;
207 
208 	qcom_glink_native_rx(rpm->glink);
209 
210 	return IRQ_HANDLED;
211 }
212 
213 static int glink_rpm_parse_toc(struct device *dev,
214 			       void __iomem *msg_ram,
215 			       size_t msg_ram_size,
216 			       struct glink_rpm_pipe *rx,
217 			       struct glink_rpm_pipe *tx)
218 {
219 	struct rpm_toc *toc;
220 	int num_entries;
221 	unsigned int id;
222 	size_t offset;
223 	size_t size;
224 	void *buf;
225 	int i;
226 
227 	buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
228 	if (!buf)
229 		return -ENOMEM;
230 
231 	__ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
232 			RPM_TOC_SIZE / sizeof(u32));
233 
234 	toc = buf;
235 
236 	if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
237 		dev_err(dev, "RPM TOC has invalid magic\n");
238 		goto err_inval;
239 	}
240 
241 	num_entries = le32_to_cpu(toc->count);
242 	if (num_entries > RPM_TOC_MAX_ENTRIES) {
243 		dev_err(dev, "Invalid number of toc entries\n");
244 		goto err_inval;
245 	}
246 
247 	for (i = 0; i < num_entries; i++) {
248 		id = le32_to_cpu(toc->entries[i].id);
249 		offset = le32_to_cpu(toc->entries[i].offset);
250 		size = le32_to_cpu(toc->entries[i].size);
251 
252 		if (offset > msg_ram_size || offset + size > msg_ram_size) {
253 			dev_err(dev, "TOC entry with invalid size\n");
254 			continue;
255 		}
256 
257 		switch (id) {
258 		case RPM_RX_FIFO_ID:
259 			rx->native.length = size;
260 
261 			rx->tail = msg_ram + offset;
262 			rx->head = msg_ram + offset + sizeof(u32);
263 			rx->fifo = msg_ram + offset + 2 * sizeof(u32);
264 			break;
265 		case RPM_TX_FIFO_ID:
266 			tx->native.length = size;
267 
268 			tx->tail = msg_ram + offset;
269 			tx->head = msg_ram + offset + sizeof(u32);
270 			tx->fifo = msg_ram + offset + 2 * sizeof(u32);
271 			break;
272 		}
273 	}
274 
275 	if (!rx->fifo || !tx->fifo) {
276 		dev_err(dev, "Unable to find rx and tx descriptors\n");
277 		goto err_inval;
278 	}
279 
280 	kfree(buf);
281 	return 0;
282 
283 err_inval:
284 	kfree(buf);
285 	return -EINVAL;
286 }
287 
288 static int glink_rpm_probe(struct platform_device *pdev)
289 {
290 	struct qcom_glink *glink;
291 	struct glink_rpm *rpm;
292 	struct device_node *np;
293 	void __iomem *msg_ram;
294 	size_t msg_ram_size;
295 	struct device *dev = &pdev->dev;
296 	struct resource r;
297 	int ret;
298 
299 	rpm = devm_kzalloc(&pdev->dev, sizeof(*rpm), GFP_KERNEL);
300 	if (!rpm)
301 		return -ENOMEM;
302 
303 	np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
304 	ret = of_address_to_resource(np, 0, &r);
305 	of_node_put(np);
306 	if (ret)
307 		return ret;
308 
309 	msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
310 	msg_ram_size = resource_size(&r);
311 	if (!msg_ram)
312 		return -ENOMEM;
313 
314 	ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
315 				  &rpm->rx_pipe, &rpm->tx_pipe);
316 	if (ret)
317 		return ret;
318 
319 	rpm->irq = of_irq_get(dev->of_node, 0);
320 	ret = devm_request_irq(dev, rpm->irq, qcom_glink_rpm_intr,
321 			       IRQF_NO_SUSPEND | IRQF_NO_AUTOEN,
322 			       "glink-rpm", rpm);
323 	if (ret) {
324 		dev_err(dev, "failed to request IRQ\n");
325 		return ret;
326 	}
327 
328 	rpm->mbox_client.dev = dev;
329 	rpm->mbox_client.knows_txdone = true;
330 	rpm->mbox_chan = mbox_request_channel(&rpm->mbox_client, 0);
331 	if (IS_ERR(rpm->mbox_chan))
332 		return dev_err_probe(dev, PTR_ERR(rpm->mbox_chan), "failed to acquire IPC channel\n");
333 
334 	/* Pipe specific accessors */
335 	rpm->rx_pipe.native.avail = glink_rpm_rx_avail;
336 	rpm->rx_pipe.native.peek = glink_rpm_rx_peek;
337 	rpm->rx_pipe.native.advance = glink_rpm_rx_advance;
338 	rpm->tx_pipe.native.avail = glink_rpm_tx_avail;
339 	rpm->tx_pipe.native.write = glink_rpm_tx_write;
340 	rpm->tx_pipe.native.kick = glink_rpm_tx_kick;
341 
342 	writel(0, rpm->tx_pipe.head);
343 	writel(0, rpm->rx_pipe.tail);
344 
345 	glink = qcom_glink_native_probe(dev,
346 					0,
347 					&rpm->rx_pipe.native,
348 					&rpm->tx_pipe.native,
349 					true);
350 	if (IS_ERR(glink)) {
351 		mbox_free_channel(rpm->mbox_chan);
352 		return PTR_ERR(glink);
353 	}
354 
355 	rpm->glink = glink;
356 
357 	platform_set_drvdata(pdev, rpm);
358 
359 	enable_irq(rpm->irq);
360 
361 	return 0;
362 }
363 
364 static void glink_rpm_remove(struct platform_device *pdev)
365 {
366 	struct glink_rpm *rpm = platform_get_drvdata(pdev);
367 	struct qcom_glink *glink = rpm->glink;
368 
369 	disable_irq(rpm->irq);
370 
371 	qcom_glink_native_remove(glink);
372 
373 	mbox_free_channel(rpm->mbox_chan);
374 }
375 
376 static const struct of_device_id glink_rpm_of_match[] = {
377 	{ .compatible = "qcom,glink-rpm" },
378 	{}
379 };
380 MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
381 
382 static struct platform_driver glink_rpm_driver = {
383 	.probe = glink_rpm_probe,
384 	.remove_new = glink_rpm_remove,
385 	.driver = {
386 		.name = "qcom_glink_rpm",
387 		.of_match_table = glink_rpm_of_match,
388 	},
389 };
390 
391 static int __init glink_rpm_init(void)
392 {
393 	return platform_driver_register(&glink_rpm_driver);
394 }
395 subsys_initcall(glink_rpm_init);
396 
397 static void __exit glink_rpm_exit(void)
398 {
399 	platform_driver_unregister(&glink_rpm_driver);
400 }
401 module_exit(glink_rpm_exit);
402 
403 MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
404 MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
405 MODULE_LICENSE("GPL v2");
406