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 */
 25int 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}
 40EXPORT_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 */
 51static 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
 63static 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;
118out:
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
128static 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
144static struct platform_driver imx_dsp_driver = {
145	.driver = {
146		.name = "imx-dsp",
147	},
148	.probe = imx_dsp_probe,
149	.remove = imx_dsp_remove,
150};
151builtin_platform_driver(imx_dsp_driver);
152
153MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
154MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
155MODULE_LICENSE("GPL v2");