drivers/firmware/imx/imx-dsp.c

   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");