1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright 2019 NXP
4 * Author: Daniel Baluta <daniel.baluta@nxp.com>
5 *
6 * Implementation of the DSP IPC interface (host side)
7 */
8
9 #include <linux/firmware/imx/dsp.h>
10 #include <linux/kernel.h>
11 #include <linux/mailbox_client.h>
12 #include <linux/module.h>
13 #include <linux/of_platform.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16
17 /*
18 * imx_dsp_ring_doorbell - triggers an interrupt on the other side (DSP)
19 *
20 * @dsp: DSP IPC handle
21 * @chan_idx: index of the channel where to trigger the interrupt
22 *
23 * Returns non-negative value for success, negative value for error
24 */
imx_dsp_ring_doorbell(struct imx_dsp_ipc * ipc,unsigned int idx)25 int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc, unsigned int idx)
26 {
27 int ret;
28 struct imx_dsp_chan *dsp_chan;
29
30 if (idx >= DSP_MU_CHAN_NUM)
31 return -EINVAL;
32
33 dsp_chan = &ipc->chans[idx];
34 ret = mbox_send_message(dsp_chan->ch, NULL);
35 if (ret < 0)
36 return ret;
37
38 return 0;
39 }
40 EXPORT_SYMBOL(imx_dsp_ring_doorbell);
41
42 /*
43 * imx_dsp_handle_rx - rx callback used by imx mailbox
44 *
45 * @c: mbox client
46 * @msg: message received
47 *
48 * Users of DSP IPC will need to privde handle_reply and handle_request
49 * callbacks.
50 */
imx_dsp_handle_rx(struct mbox_client * c,void * msg)51 static void imx_dsp_handle_rx(struct mbox_client *c, void *msg)
52 {
53 struct imx_dsp_chan *chan = container_of(c, struct imx_dsp_chan, cl);
54
55 if (chan->idx == 0) {
56 chan->ipc->ops->handle_reply(chan->ipc);
57 } else {
58 chan->ipc->ops->handle_request(chan->ipc);
59 imx_dsp_ring_doorbell(chan->ipc, 1);
60 }
61 }
62
imx_dsp_request_channel(struct imx_dsp_ipc * dsp_ipc,int idx)63 struct mbox_chan *imx_dsp_request_channel(struct imx_dsp_ipc *dsp_ipc, int idx)
64 {
65 struct imx_dsp_chan *dsp_chan;
66
67 if (idx >= DSP_MU_CHAN_NUM)
68 return ERR_PTR(-EINVAL);
69
70 dsp_chan = &dsp_ipc->chans[idx];
71 dsp_chan->ch = mbox_request_channel_byname(&dsp_chan->cl, dsp_chan->name);
72 return dsp_chan->ch;
73 }
74 EXPORT_SYMBOL(imx_dsp_request_channel);
75
imx_dsp_free_channel(struct imx_dsp_ipc * dsp_ipc,int idx)76 void imx_dsp_free_channel(struct imx_dsp_ipc *dsp_ipc, int idx)
77 {
78 struct imx_dsp_chan *dsp_chan;
79
80 if (idx >= DSP_MU_CHAN_NUM)
81 return;
82
83 dsp_chan = &dsp_ipc->chans[idx];
84 mbox_free_channel(dsp_chan->ch);
85 }
86 EXPORT_SYMBOL(imx_dsp_free_channel);
87
imx_dsp_setup_channels(struct imx_dsp_ipc * dsp_ipc)88 static int imx_dsp_setup_channels(struct imx_dsp_ipc *dsp_ipc)
89 {
90 struct device *dev = dsp_ipc->dev;
91 struct imx_dsp_chan *dsp_chan;
92 struct mbox_client *cl;
93 char *chan_name;
94 int ret;
95 int i, j;
96
97 for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
98 if (i < 2)
99 chan_name = kasprintf(GFP_KERNEL, "txdb%d", i);
100 else
101 chan_name = kasprintf(GFP_KERNEL, "rxdb%d", i - 2);
102
103 if (!chan_name)
104 return -ENOMEM;
105
106 dsp_chan = &dsp_ipc->chans[i];
107 dsp_chan->name = chan_name;
108 cl = &dsp_chan->cl;
109 cl->dev = dev;
110 cl->tx_block = false;
111 cl->knows_txdone = true;
112 cl->rx_callback = imx_dsp_handle_rx;
113
114 dsp_chan->ipc = dsp_ipc;
115 dsp_chan->idx = i % 2;
116 dsp_chan->ch = mbox_request_channel_byname(cl, chan_name);
117 if (IS_ERR(dsp_chan->ch)) {
118 ret = PTR_ERR(dsp_chan->ch);
119 if (ret != -EPROBE_DEFER)
120 dev_err(dev, "Failed to request mbox chan %s ret %d\n",
121 chan_name, ret);
122 kfree(dsp_chan->name);
123 goto out;
124 }
125
126 dev_dbg(dev, "request mbox chan %s\n", chan_name);
127 }
128
129 return 0;
130 out:
131 for (j = 0; j < i; j++) {
132 dsp_chan = &dsp_ipc->chans[j];
133 mbox_free_channel(dsp_chan->ch);
134 kfree(dsp_chan->name);
135 }
136
137 return ret;
138 }
139
imx_dsp_probe(struct platform_device * pdev)140 static int imx_dsp_probe(struct platform_device *pdev)
141 {
142 struct device *dev = &pdev->dev;
143 struct imx_dsp_ipc *dsp_ipc;
144 int ret;
145
146 device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
147
148 dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
149 if (!dsp_ipc)
150 return -ENOMEM;
151
152 dsp_ipc->dev = dev;
153 dev_set_drvdata(dev, dsp_ipc);
154
155 ret = imx_dsp_setup_channels(dsp_ipc);
156 if (ret < 0)
157 return ret;
158
159 dev_info(dev, "NXP i.MX DSP IPC initialized\n");
160
161 return 0;
162 }
163
imx_dsp_remove(struct platform_device * pdev)164 static int imx_dsp_remove(struct platform_device *pdev)
165 {
166 struct imx_dsp_chan *dsp_chan;
167 struct imx_dsp_ipc *dsp_ipc;
168 int i;
169
170 dsp_ipc = dev_get_drvdata(&pdev->dev);
171
172 for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
173 dsp_chan = &dsp_ipc->chans[i];
174 mbox_free_channel(dsp_chan->ch);
175 kfree(dsp_chan->name);
176 }
177
178 return 0;
179 }
180
181 static struct platform_driver imx_dsp_driver = {
182 .driver = {
183 .name = "imx-dsp",
184 },
185 .probe = imx_dsp_probe,
186 .remove = imx_dsp_remove,
187 };
188 builtin_platform_driver(imx_dsp_driver);
189
190 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
191 MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
192 MODULE_LICENSE("GPL v2");
193