1 /*
2  * Copyright (c) 2016-2017, Linaro Ltd
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 and
6  * only version 2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11  * GNU General Public License for more details.
12  */
13 
14 #include <linux/idr.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/list.h>
18 #include <linux/mfd/syscon.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/of_address.h>
22 #include <linux/platform_device.h>
23 #include <linux/regmap.h>
24 #include <linux/rpmsg.h>
25 #include <linux/slab.h>
26 #include <linux/workqueue.h>
27 #include <linux/mailbox_client.h>
28 
29 #include "rpmsg_internal.h"
30 #include "qcom_glink_native.h"
31 
32 #define RPM_TOC_SIZE		256
33 #define RPM_TOC_MAGIC		0x67727430 /* grt0 */
34 #define RPM_TOC_MAX_ENTRIES	((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
35 				 sizeof(struct rpm_toc_entry))
36 
37 #define RPM_TX_FIFO_ID		0x61703272 /* ap2r */
38 #define RPM_RX_FIFO_ID		0x72326170 /* r2ap */
39 
40 #define to_rpm_pipe(p) container_of(p, struct glink_rpm_pipe, native)
41 
42 struct rpm_toc_entry {
43 	__le32 id;
44 	__le32 offset;
45 	__le32 size;
46 } __packed;
47 
48 struct rpm_toc {
49 	__le32 magic;
50 	__le32 count;
51 
52 	struct rpm_toc_entry entries[];
53 } __packed;
54 
55 struct glink_rpm_pipe {
56 	struct qcom_glink_pipe native;
57 
58 	void __iomem *tail;
59 	void __iomem *head;
60 
61 	void __iomem *fifo;
62 };
63 
64 static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
65 {
66 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
67 	unsigned int head;
68 	unsigned int tail;
69 
70 	head = readl(pipe->head);
71 	tail = readl(pipe->tail);
72 
73 	if (head < tail)
74 		return pipe->native.length - tail + head;
75 	else
76 		return head - tail;
77 }
78 
79 static void glink_rpm_rx_peak(struct qcom_glink_pipe *glink_pipe,
80 			      void *data, unsigned int offset, size_t count)
81 {
82 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
83 	unsigned int tail;
84 	size_t len;
85 
86 	tail = readl(pipe->tail);
87 	tail += offset;
88 	if (tail >= pipe->native.length)
89 		tail -= pipe->native.length;
90 
91 	len = min_t(size_t, count, pipe->native.length - tail);
92 	if (len) {
93 		__ioread32_copy(data, pipe->fifo + tail,
94 				len / sizeof(u32));
95 	}
96 
97 	if (len != count) {
98 		__ioread32_copy(data + len, pipe->fifo,
99 				(count - len) / sizeof(u32));
100 	}
101 }
102 
103 static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
104 				 size_t count)
105 {
106 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
107 	unsigned int tail;
108 
109 	tail = readl(pipe->tail);
110 
111 	tail += count;
112 	if (tail >= pipe->native.length)
113 		tail -= pipe->native.length;
114 
115 	writel(tail, pipe->tail);
116 }
117 
118 static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
119 {
120 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
121 	unsigned int head;
122 	unsigned int tail;
123 
124 	head = readl(pipe->head);
125 	tail = readl(pipe->tail);
126 
127 	if (tail <= head)
128 		return pipe->native.length - head + tail;
129 	else
130 		return tail - head;
131 }
132 
133 static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
134 					   unsigned int head,
135 					   const void *data, size_t count)
136 {
137 	size_t len;
138 
139 	len = min_t(size_t, count, pipe->native.length - head);
140 	if (len) {
141 		__iowrite32_copy(pipe->fifo + head, data,
142 				 len / sizeof(u32));
143 	}
144 
145 	if (len != count) {
146 		__iowrite32_copy(pipe->fifo, data + len,
147 				 (count - len) / sizeof(u32));
148 	}
149 
150 	head += count;
151 	if (head >= pipe->native.length)
152 		head -= pipe->native.length;
153 
154 	return head;
155 }
156 
157 static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
158 			       const void *hdr, size_t hlen,
159 			       const void *data, size_t dlen)
160 {
161 	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
162 	size_t tlen = hlen + dlen;
163 	size_t aligned_dlen;
164 	unsigned int head;
165 	char padding[8] = {0};
166 	size_t pad;
167 
168 	/* Header length comes from glink native and is always 4 byte aligned */
169 	if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
170 		return;
171 
172 	/*
173 	 * Move the unaligned tail of the message to the padding chunk, to
174 	 * ensure word aligned accesses
175 	 */
176 	aligned_dlen = ALIGN_DOWN(dlen, 4);
177 	if (aligned_dlen != dlen)
178 		memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
179 
180 	head = readl(pipe->head);
181 	head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
182 	head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
183 
184 	pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
185 	if (pad)
186 		head = glink_rpm_tx_write_one(pipe, head, padding, pad);
187 	writel(head, pipe->head);
188 }
189 
190 static int glink_rpm_parse_toc(struct device *dev,
191 			       void __iomem *msg_ram,
192 			       size_t msg_ram_size,
193 			       struct glink_rpm_pipe *rx,
194 			       struct glink_rpm_pipe *tx)
195 {
196 	struct rpm_toc *toc;
197 	int num_entries;
198 	unsigned int id;
199 	size_t offset;
200 	size_t size;
201 	void *buf;
202 	int i;
203 
204 	buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
205 	if (!buf)
206 		return -ENOMEM;
207 
208 	__ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
209 			RPM_TOC_SIZE / sizeof(u32));
210 
211 	toc = buf;
212 
213 	if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
214 		dev_err(dev, "RPM TOC has invalid magic\n");
215 		goto err_inval;
216 	}
217 
218 	num_entries = le32_to_cpu(toc->count);
219 	if (num_entries > RPM_TOC_MAX_ENTRIES) {
220 		dev_err(dev, "Invalid number of toc entries\n");
221 		goto err_inval;
222 	}
223 
224 	for (i = 0; i < num_entries; i++) {
225 		id = le32_to_cpu(toc->entries[i].id);
226 		offset = le32_to_cpu(toc->entries[i].offset);
227 		size = le32_to_cpu(toc->entries[i].size);
228 
229 		if (offset > msg_ram_size || offset + size > msg_ram_size) {
230 			dev_err(dev, "TOC entry with invalid size\n");
231 			continue;
232 		}
233 
234 		switch (id) {
235 		case RPM_RX_FIFO_ID:
236 			rx->native.length = size;
237 
238 			rx->tail = msg_ram + offset;
239 			rx->head = msg_ram + offset + sizeof(u32);
240 			rx->fifo = msg_ram + offset + 2 * sizeof(u32);
241 			break;
242 		case RPM_TX_FIFO_ID:
243 			tx->native.length = size;
244 
245 			tx->tail = msg_ram + offset;
246 			tx->head = msg_ram + offset + sizeof(u32);
247 			tx->fifo = msg_ram + offset + 2 * sizeof(u32);
248 			break;
249 		}
250 	}
251 
252 	if (!rx->fifo || !tx->fifo) {
253 		dev_err(dev, "Unable to find rx and tx descriptors\n");
254 		goto err_inval;
255 	}
256 
257 	kfree(buf);
258 	return 0;
259 
260 err_inval:
261 	kfree(buf);
262 	return -EINVAL;
263 }
264 
265 static int glink_rpm_probe(struct platform_device *pdev)
266 {
267 	struct qcom_glink *glink;
268 	struct glink_rpm_pipe *rx_pipe;
269 	struct glink_rpm_pipe *tx_pipe;
270 	struct device_node *np;
271 	void __iomem *msg_ram;
272 	size_t msg_ram_size;
273 	struct device *dev = &pdev->dev;
274 	struct resource r;
275 	int ret;
276 
277 	rx_pipe = devm_kzalloc(&pdev->dev, sizeof(*rx_pipe), GFP_KERNEL);
278 	tx_pipe = devm_kzalloc(&pdev->dev, sizeof(*tx_pipe), GFP_KERNEL);
279 	if (!rx_pipe || !tx_pipe)
280 		return -ENOMEM;
281 
282 	np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
283 	ret = of_address_to_resource(np, 0, &r);
284 	of_node_put(np);
285 	if (ret)
286 		return ret;
287 
288 	msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
289 	msg_ram_size = resource_size(&r);
290 	if (!msg_ram)
291 		return -ENOMEM;
292 
293 	ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
294 				  rx_pipe, tx_pipe);
295 	if (ret)
296 		return ret;
297 
298 	/* Pipe specific accessors */
299 	rx_pipe->native.avail = glink_rpm_rx_avail;
300 	rx_pipe->native.peak = glink_rpm_rx_peak;
301 	rx_pipe->native.advance = glink_rpm_rx_advance;
302 	tx_pipe->native.avail = glink_rpm_tx_avail;
303 	tx_pipe->native.write = glink_rpm_tx_write;
304 
305 	writel(0, tx_pipe->head);
306 	writel(0, rx_pipe->tail);
307 
308 	glink = qcom_glink_native_probe(&pdev->dev,
309 					0,
310 					&rx_pipe->native,
311 					&tx_pipe->native,
312 					true);
313 	if (IS_ERR(glink))
314 		return PTR_ERR(glink);
315 
316 	platform_set_drvdata(pdev, glink);
317 
318 	return 0;
319 }
320 
321 static int glink_rpm_remove(struct platform_device *pdev)
322 {
323 	struct qcom_glink *glink = platform_get_drvdata(pdev);
324 
325 	qcom_glink_native_remove(glink);
326 
327 	return 0;
328 }
329 
330 static const struct of_device_id glink_rpm_of_match[] = {
331 	{ .compatible = "qcom,glink-rpm" },
332 	{}
333 };
334 MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
335 
336 static struct platform_driver glink_rpm_driver = {
337 	.probe = glink_rpm_probe,
338 	.remove = glink_rpm_remove,
339 	.driver = {
340 		.name = "qcom_glink_rpm",
341 		.of_match_table = glink_rpm_of_match,
342 	},
343 };
344 
345 static int __init glink_rpm_init(void)
346 {
347 	return platform_driver_register(&glink_rpm_driver);
348 }
349 subsys_initcall(glink_rpm_init);
350 
351 static void __exit glink_rpm_exit(void)
352 {
353 	platform_driver_unregister(&glink_rpm_driver);
354 }
355 module_exit(glink_rpm_exit);
356 
357 MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
358 MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
359 MODULE_LICENSE("GPL v2");
360