xref: /openbmc/linux/drivers/rpmsg/qcom_glink_rpm.c (revision 7731b8bc94e599c9a79e428f3359ff2c34b7576a)
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/platform_device.h>
15  #include <linux/regmap.h>
16  #include <linux/rpmsg.h>
17  #include <linux/slab.h>
18  #include <linux/workqueue.h>
19  #include <linux/mailbox_client.h>
20  
21  #include "rpmsg_internal.h"
22  #include "qcom_glink_native.h"
23  
24  #define RPM_TOC_SIZE		256
25  #define RPM_TOC_MAGIC		0x67727430 /* grt0 */
26  #define RPM_TOC_MAX_ENTRIES	((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
27  				 sizeof(struct rpm_toc_entry))
28  
29  #define RPM_TX_FIFO_ID		0x61703272 /* ap2r */
30  #define RPM_RX_FIFO_ID		0x72326170 /* r2ap */
31  
32  #define to_rpm_pipe(p) container_of(p, struct glink_rpm_pipe, native)
33  
34  struct rpm_toc_entry {
35  	__le32 id;
36  	__le32 offset;
37  	__le32 size;
38  } __packed;
39  
40  struct rpm_toc {
41  	__le32 magic;
42  	__le32 count;
43  
44  	struct rpm_toc_entry entries[];
45  } __packed;
46  
47  struct glink_rpm_pipe {
48  	struct qcom_glink_pipe native;
49  
50  	void __iomem *tail;
51  	void __iomem *head;
52  
53  	void __iomem *fifo;
54  };
55  
56  static size_t glink_rpm_rx_avail(struct qcom_glink_pipe *glink_pipe)
57  {
58  	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
59  	unsigned int head;
60  	unsigned int tail;
61  
62  	head = readl(pipe->head);
63  	tail = readl(pipe->tail);
64  
65  	if (head < tail)
66  		return pipe->native.length - tail + head;
67  	else
68  		return head - tail;
69  }
70  
71  static void glink_rpm_rx_peak(struct qcom_glink_pipe *glink_pipe,
72  			      void *data, unsigned int offset, size_t count)
73  {
74  	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
75  	unsigned int tail;
76  	size_t len;
77  
78  	tail = readl(pipe->tail);
79  	tail += offset;
80  	if (tail >= pipe->native.length)
81  		tail -= pipe->native.length;
82  
83  	len = min_t(size_t, count, pipe->native.length - tail);
84  	if (len) {
85  		__ioread32_copy(data, pipe->fifo + tail,
86  				len / sizeof(u32));
87  	}
88  
89  	if (len != count) {
90  		__ioread32_copy(data + len, pipe->fifo,
91  				(count - len) / sizeof(u32));
92  	}
93  }
94  
95  static void glink_rpm_rx_advance(struct qcom_glink_pipe *glink_pipe,
96  				 size_t count)
97  {
98  	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
99  	unsigned int tail;
100  
101  	tail = readl(pipe->tail);
102  
103  	tail += count;
104  	if (tail >= pipe->native.length)
105  		tail -= pipe->native.length;
106  
107  	writel(tail, pipe->tail);
108  }
109  
110  static size_t glink_rpm_tx_avail(struct qcom_glink_pipe *glink_pipe)
111  {
112  	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
113  	unsigned int head;
114  	unsigned int tail;
115  
116  	head = readl(pipe->head);
117  	tail = readl(pipe->tail);
118  
119  	if (tail <= head)
120  		return pipe->native.length - head + tail;
121  	else
122  		return tail - head;
123  }
124  
125  static unsigned int glink_rpm_tx_write_one(struct glink_rpm_pipe *pipe,
126  					   unsigned int head,
127  					   const void *data, size_t count)
128  {
129  	size_t len;
130  
131  	len = min_t(size_t, count, pipe->native.length - head);
132  	if (len) {
133  		__iowrite32_copy(pipe->fifo + head, data,
134  				 len / sizeof(u32));
135  	}
136  
137  	if (len != count) {
138  		__iowrite32_copy(pipe->fifo, data + len,
139  				 (count - len) / sizeof(u32));
140  	}
141  
142  	head += count;
143  	if (head >= pipe->native.length)
144  		head -= pipe->native.length;
145  
146  	return head;
147  }
148  
149  static void glink_rpm_tx_write(struct qcom_glink_pipe *glink_pipe,
150  			       const void *hdr, size_t hlen,
151  			       const void *data, size_t dlen)
152  {
153  	struct glink_rpm_pipe *pipe = to_rpm_pipe(glink_pipe);
154  	size_t tlen = hlen + dlen;
155  	size_t aligned_dlen;
156  	unsigned int head;
157  	char padding[8] = {0};
158  	size_t pad;
159  
160  	/* Header length comes from glink native and is always 4 byte aligned */
161  	if (WARN(hlen % 4, "Glink Header length must be 4 bytes aligned\n"))
162  		return;
163  
164  	/*
165  	 * Move the unaligned tail of the message to the padding chunk, to
166  	 * ensure word aligned accesses
167  	 */
168  	aligned_dlen = ALIGN_DOWN(dlen, 4);
169  	if (aligned_dlen != dlen)
170  		memcpy(padding, data + aligned_dlen, dlen - aligned_dlen);
171  
172  	head = readl(pipe->head);
173  	head = glink_rpm_tx_write_one(pipe, head, hdr, hlen);
174  	head = glink_rpm_tx_write_one(pipe, head, data, aligned_dlen);
175  
176  	pad = ALIGN(tlen, 8) - ALIGN_DOWN(tlen, 4);
177  	if (pad)
178  		head = glink_rpm_tx_write_one(pipe, head, padding, pad);
179  	writel(head, pipe->head);
180  }
181  
182  static int glink_rpm_parse_toc(struct device *dev,
183  			       void __iomem *msg_ram,
184  			       size_t msg_ram_size,
185  			       struct glink_rpm_pipe *rx,
186  			       struct glink_rpm_pipe *tx)
187  {
188  	struct rpm_toc *toc;
189  	int num_entries;
190  	unsigned int id;
191  	size_t offset;
192  	size_t size;
193  	void *buf;
194  	int i;
195  
196  	buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
197  	if (!buf)
198  		return -ENOMEM;
199  
200  	__ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
201  			RPM_TOC_SIZE / sizeof(u32));
202  
203  	toc = buf;
204  
205  	if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
206  		dev_err(dev, "RPM TOC has invalid magic\n");
207  		goto err_inval;
208  	}
209  
210  	num_entries = le32_to_cpu(toc->count);
211  	if (num_entries > RPM_TOC_MAX_ENTRIES) {
212  		dev_err(dev, "Invalid number of toc entries\n");
213  		goto err_inval;
214  	}
215  
216  	for (i = 0; i < num_entries; i++) {
217  		id = le32_to_cpu(toc->entries[i].id);
218  		offset = le32_to_cpu(toc->entries[i].offset);
219  		size = le32_to_cpu(toc->entries[i].size);
220  
221  		if (offset > msg_ram_size || offset + size > msg_ram_size) {
222  			dev_err(dev, "TOC entry with invalid size\n");
223  			continue;
224  		}
225  
226  		switch (id) {
227  		case RPM_RX_FIFO_ID:
228  			rx->native.length = size;
229  
230  			rx->tail = msg_ram + offset;
231  			rx->head = msg_ram + offset + sizeof(u32);
232  			rx->fifo = msg_ram + offset + 2 * sizeof(u32);
233  			break;
234  		case RPM_TX_FIFO_ID:
235  			tx->native.length = size;
236  
237  			tx->tail = msg_ram + offset;
238  			tx->head = msg_ram + offset + sizeof(u32);
239  			tx->fifo = msg_ram + offset + 2 * sizeof(u32);
240  			break;
241  		}
242  	}
243  
244  	if (!rx->fifo || !tx->fifo) {
245  		dev_err(dev, "Unable to find rx and tx descriptors\n");
246  		goto err_inval;
247  	}
248  
249  	kfree(buf);
250  	return 0;
251  
252  err_inval:
253  	kfree(buf);
254  	return -EINVAL;
255  }
256  
257  static int glink_rpm_probe(struct platform_device *pdev)
258  {
259  	struct qcom_glink *glink;
260  	struct glink_rpm_pipe *rx_pipe;
261  	struct glink_rpm_pipe *tx_pipe;
262  	struct device_node *np;
263  	void __iomem *msg_ram;
264  	size_t msg_ram_size;
265  	struct device *dev = &pdev->dev;
266  	struct resource r;
267  	int ret;
268  
269  	rx_pipe = devm_kzalloc(&pdev->dev, sizeof(*rx_pipe), GFP_KERNEL);
270  	tx_pipe = devm_kzalloc(&pdev->dev, sizeof(*tx_pipe), GFP_KERNEL);
271  	if (!rx_pipe || !tx_pipe)
272  		return -ENOMEM;
273  
274  	np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
275  	ret = of_address_to_resource(np, 0, &r);
276  	of_node_put(np);
277  	if (ret)
278  		return ret;
279  
280  	msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
281  	msg_ram_size = resource_size(&r);
282  	if (!msg_ram)
283  		return -ENOMEM;
284  
285  	ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
286  				  rx_pipe, tx_pipe);
287  	if (ret)
288  		return ret;
289  
290  	/* Pipe specific accessors */
291  	rx_pipe->native.avail = glink_rpm_rx_avail;
292  	rx_pipe->native.peak = glink_rpm_rx_peak;
293  	rx_pipe->native.advance = glink_rpm_rx_advance;
294  	tx_pipe->native.avail = glink_rpm_tx_avail;
295  	tx_pipe->native.write = glink_rpm_tx_write;
296  
297  	writel(0, tx_pipe->head);
298  	writel(0, rx_pipe->tail);
299  
300  	glink = qcom_glink_native_probe(&pdev->dev,
301  					0,
302  					&rx_pipe->native,
303  					&tx_pipe->native,
304  					true);
305  	if (IS_ERR(glink))
306  		return PTR_ERR(glink);
307  
308  	platform_set_drvdata(pdev, glink);
309  
310  	return 0;
311  }
312  
313  static int glink_rpm_remove(struct platform_device *pdev)
314  {
315  	struct qcom_glink *glink = platform_get_drvdata(pdev);
316  
317  	qcom_glink_native_remove(glink);
318  
319  	return 0;
320  }
321  
322  static const struct of_device_id glink_rpm_of_match[] = {
323  	{ .compatible = "qcom,glink-rpm" },
324  	{}
325  };
326  MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
327  
328  static struct platform_driver glink_rpm_driver = {
329  	.probe = glink_rpm_probe,
330  	.remove = glink_rpm_remove,
331  	.driver = {
332  		.name = "qcom_glink_rpm",
333  		.of_match_table = glink_rpm_of_match,
334  	},
335  };
336  
337  static int __init glink_rpm_init(void)
338  {
339  	return platform_driver_register(&glink_rpm_driver);
340  }
341  subsys_initcall(glink_rpm_init);
342  
343  static void __exit glink_rpm_exit(void)
344  {
345  	platform_driver_unregister(&glink_rpm_driver);
346  }
347  module_exit(glink_rpm_exit);
348  
349  MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
350  MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
351  MODULE_LICENSE("GPL v2");
352