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 			goto out;
123 		}
124 
125 		dev_dbg(dev, "request mbox chan %s\n", chan_name);
126 	}
127 
128 	return 0;
129 out:
130 	for (j = 0; j < i; j++) {
131 		dsp_chan = &dsp_ipc->chans[j];
132 		mbox_free_channel(dsp_chan->ch);
133 		kfree(dsp_chan->name);
134 	}
135 
136 	return ret;
137 }
138 
imx_dsp_probe(struct platform_device * pdev)139 static int imx_dsp_probe(struct platform_device *pdev)
140 {
141 	struct device *dev = &pdev->dev;
142 	struct imx_dsp_ipc *dsp_ipc;
143 	int ret;
144 
145 	device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
146 
147 	dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
148 	if (!dsp_ipc)
149 		return -ENOMEM;
150 
151 	dsp_ipc->dev = dev;
152 	dev_set_drvdata(dev, dsp_ipc);
153 
154 	ret = imx_dsp_setup_channels(dsp_ipc);
155 	if (ret < 0)
156 		return ret;
157 
158 	dev_info(dev, "NXP i.MX DSP IPC initialized\n");
159 
160 	return 0;
161 }
162 
imx_dsp_remove(struct platform_device * pdev)163 static int imx_dsp_remove(struct platform_device *pdev)
164 {
165 	struct imx_dsp_chan *dsp_chan;
166 	struct imx_dsp_ipc *dsp_ipc;
167 	int i;
168 
169 	dsp_ipc = dev_get_drvdata(&pdev->dev);
170 
171 	for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
172 		dsp_chan = &dsp_ipc->chans[i];
173 		mbox_free_channel(dsp_chan->ch);
174 		kfree(dsp_chan->name);
175 	}
176 
177 	return 0;
178 }
179 
180 static struct platform_driver imx_dsp_driver = {
181 	.driver = {
182 		.name = "imx-dsp",
183 	},
184 	.probe = imx_dsp_probe,
185 	.remove = imx_dsp_remove,
186 };
187 builtin_platform_driver(imx_dsp_driver);
188 
189 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
190 MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
191 MODULE_LICENSE("GPL v2");
192