1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Platform driver for CDX bus.
4  *
5  * Copyright (C) 2022-2023, Advanced Micro Devices, Inc.
6  */
7 
8 #include <linux/rpmsg.h>
9 #include <linux/remoteproc.h>
10 #include <linux/of_platform.h>
11 #include <linux/cdx/cdx_bus.h>
12 #include <linux/module.h>
13 
14 #include "../cdx.h"
15 #include "cdx_controller.h"
16 #include "mcdi_functions.h"
17 #include "mcdi.h"
18 
19 static struct rpmsg_device_id cdx_rpmsg_id_table[] = {
20 	{ .name = "mcdi_ipc" },
21 	{ },
22 };
23 MODULE_DEVICE_TABLE(rpmsg, cdx_rpmsg_id_table);
24 
25 int cdx_rpmsg_send(struct cdx_mcdi *cdx_mcdi,
26 		   const struct cdx_dword *hdr, size_t hdr_len,
27 		   const struct cdx_dword *sdu, size_t sdu_len)
28 {
29 	unsigned char *send_buf;
30 	int ret;
31 
32 	send_buf = kzalloc(hdr_len + sdu_len, GFP_KERNEL);
33 	if (!send_buf)
34 		return -ENOMEM;
35 
36 	memcpy(send_buf, hdr, hdr_len);
37 	memcpy(send_buf + hdr_len, sdu, sdu_len);
38 
39 	ret = rpmsg_send(cdx_mcdi->ept, send_buf, hdr_len + sdu_len);
40 	kfree(send_buf);
41 
42 	return ret;
43 }
44 
45 static int cdx_attach_to_rproc(struct platform_device *pdev)
46 {
47 	struct device_node *r5_core_node;
48 	struct cdx_controller *cdx_c;
49 	struct cdx_mcdi *cdx_mcdi;
50 	struct device *dev;
51 	struct rproc *rp;
52 	int ret;
53 
54 	dev = &pdev->dev;
55 	cdx_c = platform_get_drvdata(pdev);
56 	cdx_mcdi = cdx_c->priv;
57 
58 	r5_core_node = of_parse_phandle(dev->of_node, "xlnx,rproc", 0);
59 	if (!r5_core_node) {
60 		dev_err(&pdev->dev, "xlnx,rproc: invalid phandle\n");
61 		return -EINVAL;
62 	}
63 
64 	rp = rproc_get_by_phandle(r5_core_node->phandle);
65 	if (!rp) {
66 		ret = -EPROBE_DEFER;
67 		goto pdev_err;
68 	}
69 
70 	/* Attach to remote processor */
71 	ret = rproc_boot(rp);
72 	if (ret) {
73 		dev_err(&pdev->dev, "Failed to attach to remote processor\n");
74 		rproc_put(rp);
75 		goto pdev_err;
76 	}
77 
78 	cdx_mcdi->r5_rproc = rp;
79 pdev_err:
80 	of_node_put(r5_core_node);
81 	return ret;
82 }
83 
84 static void cdx_detach_to_r5(struct platform_device *pdev)
85 {
86 	struct cdx_controller *cdx_c;
87 	struct cdx_mcdi *cdx_mcdi;
88 
89 	cdx_c = platform_get_drvdata(pdev);
90 	cdx_mcdi = cdx_c->priv;
91 
92 	rproc_detach(cdx_mcdi->r5_rproc);
93 	rproc_put(cdx_mcdi->r5_rproc);
94 }
95 
96 static int cdx_rpmsg_cb(struct rpmsg_device *rpdev, void *data,
97 			int len, void *priv, u32 src)
98 {
99 	struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
100 	struct cdx_mcdi *cdx_mcdi = cdx_c->priv;
101 
102 	if (len > MCDI_BUF_LEN)
103 		return -EINVAL;
104 
105 	cdx_mcdi_process_cmd(cdx_mcdi, (struct cdx_dword *)data, len);
106 
107 	return 0;
108 }
109 
110 static void cdx_rpmsg_post_probe_work(struct work_struct *work)
111 {
112 	struct cdx_controller *cdx_c;
113 	struct cdx_mcdi *cdx_mcdi;
114 
115 	cdx_mcdi = container_of(work, struct cdx_mcdi, work);
116 	cdx_c = dev_get_drvdata(&cdx_mcdi->rpdev->dev);
117 	cdx_rpmsg_post_probe(cdx_c);
118 }
119 
120 static int cdx_rpmsg_probe(struct rpmsg_device *rpdev)
121 {
122 	struct rpmsg_channel_info chinfo = {0};
123 	struct cdx_controller *cdx_c;
124 	struct cdx_mcdi *cdx_mcdi;
125 
126 	cdx_c = (struct cdx_controller *)cdx_rpmsg_id_table[0].driver_data;
127 	cdx_mcdi = cdx_c->priv;
128 
129 	chinfo.src = RPMSG_ADDR_ANY;
130 	chinfo.dst = rpdev->dst;
131 	strscpy(chinfo.name, cdx_rpmsg_id_table[0].name,
132 		strlen(cdx_rpmsg_id_table[0].name));
133 
134 	cdx_mcdi->ept = rpmsg_create_ept(rpdev, cdx_rpmsg_cb, NULL, chinfo);
135 	if (!cdx_mcdi->ept) {
136 		dev_err_probe(&rpdev->dev, -ENXIO,
137 			      "Failed to create ept for channel %s\n",
138 			      chinfo.name);
139 		return -EINVAL;
140 	}
141 
142 	cdx_mcdi->rpdev = rpdev;
143 	dev_set_drvdata(&rpdev->dev, cdx_c);
144 
145 	schedule_work(&cdx_mcdi->work);
146 	return 0;
147 }
148 
149 static void cdx_rpmsg_remove(struct rpmsg_device *rpdev)
150 {
151 	struct cdx_controller *cdx_c = dev_get_drvdata(&rpdev->dev);
152 	struct cdx_mcdi *cdx_mcdi = cdx_c->priv;
153 
154 	flush_work(&cdx_mcdi->work);
155 	cdx_rpmsg_pre_remove(cdx_c);
156 
157 	rpmsg_destroy_ept(cdx_mcdi->ept);
158 	dev_set_drvdata(&rpdev->dev, NULL);
159 }
160 
161 static struct rpmsg_driver cdx_rpmsg_driver = {
162 	.drv.name = KBUILD_MODNAME,
163 	.id_table = cdx_rpmsg_id_table,
164 	.probe = cdx_rpmsg_probe,
165 	.remove = cdx_rpmsg_remove,
166 	.callback = cdx_rpmsg_cb,
167 };
168 
169 int cdx_setup_rpmsg(struct platform_device *pdev)
170 {
171 	struct cdx_controller *cdx_c;
172 	struct cdx_mcdi *cdx_mcdi;
173 	int ret;
174 
175 	/* Attach to remote processor */
176 	ret = cdx_attach_to_rproc(pdev);
177 	if (ret)
178 		return ret;
179 
180 	cdx_c = platform_get_drvdata(pdev);
181 	cdx_mcdi = cdx_c->priv;
182 
183 	/* Register RPMsg driver */
184 	cdx_rpmsg_id_table[0].driver_data = (kernel_ulong_t)cdx_c;
185 
186 	INIT_WORK(&cdx_mcdi->work, cdx_rpmsg_post_probe_work);
187 	ret = register_rpmsg_driver(&cdx_rpmsg_driver);
188 	if (ret) {
189 		dev_err(&pdev->dev,
190 			"Failed to register cdx RPMsg driver: %d\n", ret);
191 		cdx_detach_to_r5(pdev);
192 	}
193 
194 	return ret;
195 }
196 
197 void cdx_destroy_rpmsg(struct platform_device *pdev)
198 {
199 	unregister_rpmsg_driver(&cdx_rpmsg_driver);
200 
201 	cdx_detach_to_r5(pdev);
202 }
203