1 /*
2  * Copyright (c) 2016, 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/io.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/interrupt.h>
19 #include <linux/platform_device.h>
20 #include <linux/mfd/syscon.h>
21 #include <linux/slab.h>
22 #include <linux/rpmsg.h>
23 #include <linux/idr.h>
24 #include <linux/circ_buf.h>
25 #include <linux/soc/qcom/smem.h>
26 #include <linux/sizes.h>
27 #include <linux/delay.h>
28 #include <linux/regmap.h>
29 #include <linux/workqueue.h>
30 #include <linux/list.h>
31 
32 #include <linux/delay.h>
33 #include <linux/rpmsg.h>
34 #include <linux/rpmsg/qcom_glink.h>
35 
36 #include "qcom_glink_native.h"
37 
38 #define FIFO_FULL_RESERVE 8
39 #define FIFO_ALIGNMENT 8
40 #define TX_BLOCKED_CMD_RESERVE 8 /* size of struct read_notif_request */
41 
42 #define SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR	478
43 #define SMEM_GLINK_NATIVE_XPRT_FIFO_0		479
44 #define SMEM_GLINK_NATIVE_XPRT_FIFO_1		480
45 
46 struct glink_smem_pipe {
47 	struct qcom_glink_pipe native;
48 
49 	__le32 *tail;
50 	__le32 *head;
51 
52 	void *fifo;
53 
54 	int remote_pid;
55 };
56 
57 #define to_smem_pipe(p) container_of(p, struct glink_smem_pipe, native)
58 
59 static size_t glink_smem_rx_avail(struct qcom_glink_pipe *np)
60 {
61 	struct glink_smem_pipe *pipe = to_smem_pipe(np);
62 	size_t len;
63 	void *fifo;
64 	u32 head;
65 	u32 tail;
66 
67 	if (!pipe->fifo) {
68 		fifo = qcom_smem_get(pipe->remote_pid,
69 				     SMEM_GLINK_NATIVE_XPRT_FIFO_1, &len);
70 		if (IS_ERR(fifo)) {
71 			pr_err("failed to acquire RX fifo handle: %ld\n",
72 			       PTR_ERR(fifo));
73 			return 0;
74 		}
75 
76 		pipe->fifo = fifo;
77 		pipe->native.length = len;
78 	}
79 
80 	head = le32_to_cpu(*pipe->head);
81 	tail = le32_to_cpu(*pipe->tail);
82 
83 	if (head < tail)
84 		return pipe->native.length - tail + head;
85 	else
86 		return head - tail;
87 }
88 
89 static void glink_smem_rx_peak(struct qcom_glink_pipe *np,
90 			       void *data, unsigned int offset, size_t count)
91 {
92 	struct glink_smem_pipe *pipe = to_smem_pipe(np);
93 	size_t len;
94 	u32 tail;
95 
96 	tail = le32_to_cpu(*pipe->tail);
97 	tail += offset;
98 	if (tail >= pipe->native.length)
99 		tail -= pipe->native.length;
100 
101 	len = min_t(size_t, count, pipe->native.length - tail);
102 	if (len) {
103 		__ioread32_copy(data, pipe->fifo + tail,
104 				len / sizeof(u32));
105 	}
106 
107 	if (len != count) {
108 		__ioread32_copy(data + len, pipe->fifo,
109 				(count - len) / sizeof(u32));
110 	}
111 }
112 
113 static void glink_smem_rx_advance(struct qcom_glink_pipe *np,
114 				  size_t count)
115 {
116 	struct glink_smem_pipe *pipe = to_smem_pipe(np);
117 	u32 tail;
118 
119 	tail = le32_to_cpu(*pipe->tail);
120 
121 	tail += count;
122 	if (tail > pipe->native.length)
123 		tail -= pipe->native.length;
124 
125 	*pipe->tail = cpu_to_le32(tail);
126 }
127 
128 static size_t glink_smem_tx_avail(struct qcom_glink_pipe *np)
129 {
130 	struct glink_smem_pipe *pipe = to_smem_pipe(np);
131 	u32 head;
132 	u32 tail;
133 	u32 avail;
134 
135 	head = le32_to_cpu(*pipe->head);
136 	tail = le32_to_cpu(*pipe->tail);
137 
138 	if (tail <= head)
139 		avail = pipe->native.length - head + tail;
140 	else
141 		avail = tail - head;
142 
143 	if (avail < (FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE))
144 		avail = 0;
145 	else
146 		avail -= FIFO_FULL_RESERVE + TX_BLOCKED_CMD_RESERVE;
147 
148 	return avail;
149 }
150 
151 static unsigned int glink_smem_tx_write_one(struct glink_smem_pipe *pipe,
152 					    unsigned int head,
153 					    const void *data, size_t count)
154 {
155 	size_t len;
156 
157 	len = min_t(size_t, count, pipe->native.length - head);
158 	if (len)
159 		memcpy(pipe->fifo + head, data, len);
160 
161 	if (len != count)
162 		memcpy(pipe->fifo, data + len, count - len);
163 
164 	head += count;
165 	if (head >= pipe->native.length)
166 		head -= pipe->native.length;
167 
168 	return head;
169 }
170 
171 static void glink_smem_tx_write(struct qcom_glink_pipe *glink_pipe,
172 				const void *hdr, size_t hlen,
173 				const void *data, size_t dlen)
174 {
175 	struct glink_smem_pipe *pipe = to_smem_pipe(glink_pipe);
176 	unsigned int head;
177 
178 	head = le32_to_cpu(*pipe->head);
179 
180 	head = glink_smem_tx_write_one(pipe, head, hdr, hlen);
181 	head = glink_smem_tx_write_one(pipe, head, data, dlen);
182 
183 	/* Ensure head is always aligned to 8 bytes */
184 	head = ALIGN(head, 8);
185 	if (head >= pipe->native.length)
186 		head -= pipe->native.length;
187 
188 	*pipe->head = cpu_to_le32(head);
189 }
190 
191 static void qcom_glink_smem_release(struct device *dev)
192 {
193 	kfree(dev);
194 }
195 
196 struct qcom_glink *qcom_glink_smem_register(struct device *parent,
197 					    struct device_node *node)
198 {
199 	struct glink_smem_pipe *rx_pipe;
200 	struct glink_smem_pipe *tx_pipe;
201 	struct qcom_glink *glink;
202 	struct device *dev;
203 	u32 remote_pid;
204 	__le32 *descs;
205 	size_t size;
206 	int ret;
207 
208 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
209 	if (!dev)
210 		return ERR_PTR(-ENOMEM);
211 
212 	dev->parent = parent;
213 	dev->of_node = node;
214 	dev->release = qcom_glink_smem_release;
215 	dev_set_name(dev, "%s:%s", node->parent->name, node->name);
216 	ret = device_register(dev);
217 	if (ret) {
218 		pr_err("failed to register glink edge\n");
219 		return ERR_PTR(ret);
220 	}
221 
222 	ret = of_property_read_u32(dev->of_node, "qcom,remote-pid",
223 				   &remote_pid);
224 	if (ret) {
225 		dev_err(dev, "failed to parse qcom,remote-pid\n");
226 		goto err_put_dev;
227 	}
228 
229 	rx_pipe = devm_kzalloc(dev, sizeof(*rx_pipe), GFP_KERNEL);
230 	tx_pipe = devm_kzalloc(dev, sizeof(*tx_pipe), GFP_KERNEL);
231 	if (!rx_pipe || !tx_pipe) {
232 		ret = -ENOMEM;
233 		goto err_put_dev;
234 	}
235 
236 	ret = qcom_smem_alloc(remote_pid,
237 			      SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, 32);
238 	if (ret && ret != -EEXIST) {
239 		dev_err(dev, "failed to allocate glink descriptors\n");
240 		goto err_put_dev;
241 	}
242 
243 	descs = qcom_smem_get(remote_pid,
244 			      SMEM_GLINK_NATIVE_XPRT_DESCRIPTOR, &size);
245 	if (IS_ERR(descs)) {
246 		dev_err(dev, "failed to acquire xprt descriptor\n");
247 		ret = PTR_ERR(descs);
248 		goto err_put_dev;
249 	}
250 
251 	if (size != 32) {
252 		dev_err(dev, "glink descriptor of invalid size\n");
253 		ret = -EINVAL;
254 		goto err_put_dev;
255 	}
256 
257 	tx_pipe->tail = &descs[0];
258 	tx_pipe->head = &descs[1];
259 	rx_pipe->tail = &descs[2];
260 	rx_pipe->head = &descs[3];
261 
262 	ret = qcom_smem_alloc(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
263 			      SZ_16K);
264 	if (ret && ret != -EEXIST) {
265 		dev_err(dev, "failed to allocate TX fifo\n");
266 		goto err_put_dev;
267 	}
268 
269 	tx_pipe->fifo = qcom_smem_get(remote_pid, SMEM_GLINK_NATIVE_XPRT_FIFO_0,
270 				      &tx_pipe->native.length);
271 	if (IS_ERR(tx_pipe->fifo)) {
272 		dev_err(dev, "failed to acquire TX fifo\n");
273 		ret = PTR_ERR(tx_pipe->fifo);
274 		goto err_put_dev;
275 	}
276 
277 	rx_pipe->native.avail = glink_smem_rx_avail;
278 	rx_pipe->native.peak = glink_smem_rx_peak;
279 	rx_pipe->native.advance = glink_smem_rx_advance;
280 	rx_pipe->remote_pid = remote_pid;
281 
282 	tx_pipe->native.avail = glink_smem_tx_avail;
283 	tx_pipe->native.write = glink_smem_tx_write;
284 	tx_pipe->remote_pid = remote_pid;
285 
286 	*rx_pipe->tail = 0;
287 	*tx_pipe->head = 0;
288 
289 	glink = qcom_glink_native_probe(dev,
290 					GLINK_FEATURE_INTENT_REUSE,
291 					&rx_pipe->native, &tx_pipe->native,
292 					false);
293 	if (IS_ERR(glink)) {
294 		ret = PTR_ERR(glink);
295 		goto err_put_dev;
296 	}
297 
298 	return glink;
299 
300 err_put_dev:
301 	put_device(dev);
302 
303 	return ERR_PTR(ret);
304 }
305 EXPORT_SYMBOL_GPL(qcom_glink_smem_register);
306 
307 void qcom_glink_smem_unregister(struct qcom_glink *glink)
308 {
309 	qcom_glink_native_remove(glink);
310 	qcom_glink_native_unregister(glink);
311 }
312 EXPORT_SYMBOL_GPL(qcom_glink_smem_unregister);
313 
314 MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
315 MODULE_DESCRIPTION("Qualcomm GLINK SMEM driver");
316 MODULE_LICENSE("GPL v2");
317