xref: /openbmc/linux/drivers/firmware/imx/imx-dsp.c (revision 15d5761a)
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  */
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  */
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 
63 static int imx_dsp_probe(struct platform_device *pdev)
64 {
65 	struct device *dev = &pdev->dev;
66 	struct imx_dsp_ipc *dsp_ipc;
67 	struct imx_dsp_chan *dsp_chan;
68 	struct mbox_client *cl;
69 	char *chan_name;
70 	int ret;
71 	int i, j;
72 
73 	device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
74 
75 	dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
76 	if (!dsp_ipc)
77 		return -ENOMEM;
78 
79 	for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
80 		if (i < 2)
81 			chan_name = kasprintf(GFP_KERNEL, "txdb%d", i);
82 		else
83 			chan_name = kasprintf(GFP_KERNEL, "rxdb%d", i - 2);
84 
85 		if (!chan_name)
86 			return -ENOMEM;
87 
88 		dsp_chan = &dsp_ipc->chans[i];
89 		cl = &dsp_chan->cl;
90 		cl->dev = dev;
91 		cl->tx_block = false;
92 		cl->knows_txdone = true;
93 		cl->rx_callback = imx_dsp_handle_rx;
94 
95 		dsp_chan->ipc = dsp_ipc;
96 		dsp_chan->idx = i % 2;
97 		dsp_chan->ch = mbox_request_channel_byname(cl, chan_name);
98 		if (IS_ERR(dsp_chan->ch)) {
99 			ret = PTR_ERR(dsp_chan->ch);
100 			if (ret != -EPROBE_DEFER)
101 				dev_err(dev, "Failed to request mbox chan %s ret %d\n",
102 					chan_name, ret);
103 			goto out;
104 		}
105 
106 		dev_dbg(dev, "request mbox chan %s\n", chan_name);
107 		/* chan_name is not used anymore by framework */
108 		kfree(chan_name);
109 	}
110 
111 	dsp_ipc->dev = dev;
112 
113 	dev_set_drvdata(dev, dsp_ipc);
114 
115 	dev_info(dev, "NXP i.MX DSP IPC initialized\n");
116 
117 	return 0;
118 out:
119 	kfree(chan_name);
120 	for (j = 0; j < i; j++) {
121 		dsp_chan = &dsp_ipc->chans[j];
122 		mbox_free_channel(dsp_chan->ch);
123 	}
124 
125 	return ret;
126 }
127 
128 static int imx_dsp_remove(struct platform_device *pdev)
129 {
130 	struct imx_dsp_chan *dsp_chan;
131 	struct imx_dsp_ipc *dsp_ipc;
132 	int i;
133 
134 	dsp_ipc = dev_get_drvdata(&pdev->dev);
135 
136 	for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
137 		dsp_chan = &dsp_ipc->chans[i];
138 		mbox_free_channel(dsp_chan->ch);
139 	}
140 
141 	return 0;
142 }
143 
144 static struct platform_driver imx_dsp_driver = {
145 	.driver = {
146 		.name = "imx-dsp",
147 	},
148 	.probe = imx_dsp_probe,
149 	.remove = imx_dsp_remove,
150 };
151 builtin_platform_driver(imx_dsp_driver);
152 
153 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
154 MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
155 MODULE_LICENSE("GPL v2");
156