firmware: imx: Add DSP IPC protocol interface

Some of i.MX8 processors (e.g i.MX8QM, i.MX8QXP) contain
the Tensilica HiFi4 DSP for advanced pre- and post-audio
processing.

The communication between Host CPU and DSP firmware is
taking place using a shared memory area for message passing
and a dedicated Messaging Unit for notifications.

DSP IPC protocol offers a doorbell interface using
imx-mailbox API.

We use 4 MU channels (2 x TXDB, 2 x RXDB) to implement a
request-reply protocol.

Connection 0 (txdb0, rxdb0):
        - Host writes messasge to shared memory [SHMEM]
	- Host sends a request [MU]
	- DSP handles request [SHMEM]
	- DSP sends reply [MU]

Connection 1 (txdb1, rxdb1):
	- DSP writes a message to shared memory [SHMEM]
	- DSP sends a request [MU]
	- Host handles request [SHMEM]
	- Host sends reply [MU]

The protocol interface will be used by a Host client to
communicate with the DSP. First client will be the i.MX8
part from Sound Open Firmware infrastructure.

The protocol offers the following interface:

On Tx:
   - imx_dsp_ring_doorbell, will be called to notify the DSP
   that it needs to handle a request.

On Rx:
   - clients need to provide two callbacks:
	.handle_reply
	.handle_request
  - the callbacks will be used by the protocol on
    notification arrival from DSP.

Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
This commit is contained in:
Daniel Baluta 2019-08-01 12:56:36 +03:00 committed by Shawn Guo
parent 73feb4d0f8
commit ffbf23d503
4 changed files with 234 additions and 0 deletions

View File

@ -1,4 +1,15 @@
# SPDX-License-Identifier: GPL-2.0-only
config IMX_DSP
bool "IMX DSP Protocol driver"
depends on IMX_MBOX
help
This enables DSP IPC protocol between host AP (Linux)
and the firmware running on DSP.
DSP exists on some i.MX8 processors (e.g i.MX8QM, i.MX8QXP).
It acts like a doorbell. Client might use shared memory to
exchange information with DSP side.
config IMX_SCU
bool "IMX SCU Protocol driver"
depends on IMX_MBOX

View File

@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_IMX_DSP) += imx-dsp.o
obj-$(CONFIG_IMX_SCU) += imx-scu.o misc.o imx-scu-irq.o
obj-$(CONFIG_IMX_SCU_PD) += scu-pd.o

View File

@ -0,0 +1,155 @@
// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2019 NXP
* Author: Daniel Baluta <daniel.baluta@nxp.com>
*
* Implementation of the DSP IPC interface (host side)
*/
#include <linux/firmware/imx/dsp.h>
#include <linux/kernel.h>
#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
/*
* imx_dsp_ring_doorbell - triggers an interrupt on the other side (DSP)
*
* @dsp: DSP IPC handle
* @chan_idx: index of the channel where to trigger the interrupt
*
* Returns non-negative value for success, negative value for error
*/
int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc, unsigned int idx)
{
int ret;
struct imx_dsp_chan *dsp_chan;
if (idx >= DSP_MU_CHAN_NUM)
return -EINVAL;
dsp_chan = &ipc->chans[idx];
ret = mbox_send_message(dsp_chan->ch, NULL);
if (ret < 0)
return ret;
return 0;
}
EXPORT_SYMBOL(imx_dsp_ring_doorbell);
/*
* imx_dsp_handle_rx - rx callback used by imx mailbox
*
* @c: mbox client
* @msg: message received
*
* Users of DSP IPC will need to privde handle_reply and handle_request
* callbacks.
*/
static void imx_dsp_handle_rx(struct mbox_client *c, void *msg)
{
struct imx_dsp_chan *chan = container_of(c, struct imx_dsp_chan, cl);
if (chan->idx == 0) {
chan->ipc->ops->handle_reply(chan->ipc);
} else {
chan->ipc->ops->handle_request(chan->ipc);
imx_dsp_ring_doorbell(chan->ipc, 1);
}
}
static int imx_dsp_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct imx_dsp_ipc *dsp_ipc;
struct imx_dsp_chan *dsp_chan;
struct mbox_client *cl;
char *chan_name;
int ret;
int i, j;
device_set_of_node_from_dev(&pdev->dev, pdev->dev.parent);
dsp_ipc = devm_kzalloc(dev, sizeof(*dsp_ipc), GFP_KERNEL);
if (!dsp_ipc)
return -ENOMEM;
for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
if (i < 2)
chan_name = kasprintf(GFP_KERNEL, "txdb%d", i);
else
chan_name = kasprintf(GFP_KERNEL, "rxdb%d", i - 2);
if (!chan_name)
return -ENOMEM;
dsp_chan = &dsp_ipc->chans[i];
cl = &dsp_chan->cl;
cl->dev = dev;
cl->tx_block = false;
cl->knows_txdone = true;
cl->rx_callback = imx_dsp_handle_rx;
dsp_chan->ipc = dsp_ipc;
dsp_chan->idx = i % 2;
dsp_chan->ch = mbox_request_channel_byname(cl, chan_name);
if (IS_ERR(dsp_chan->ch)) {
ret = PTR_ERR(dsp_chan->ch);
if (ret != -EPROBE_DEFER)
dev_err(dev, "Failed to request mbox chan %s ret %d\n",
chan_name, ret);
goto out;
}
dev_dbg(dev, "request mbox chan %s\n", chan_name);
/* chan_name is not used anymore by framework */
kfree(chan_name);
}
dsp_ipc->dev = dev;
dev_set_drvdata(dev, dsp_ipc);
dev_info(dev, "NXP i.MX DSP IPC initialized\n");
return devm_of_platform_populate(dev);
out:
kfree(chan_name);
for (j = 0; j < i; j++) {
dsp_chan = &dsp_ipc->chans[j];
mbox_free_channel(dsp_chan->ch);
}
return ret;
}
static int imx_dsp_remove(struct platform_device *pdev)
{
struct imx_dsp_chan *dsp_chan;
struct imx_dsp_ipc *dsp_ipc;
int i;
dsp_ipc = dev_get_drvdata(&pdev->dev);
for (i = 0; i < DSP_MU_CHAN_NUM; i++) {
dsp_chan = &dsp_ipc->chans[i];
mbox_free_channel(dsp_chan->ch);
}
return 0;
}
static struct platform_driver imx_dsp_driver = {
.driver = {
.name = "imx-dsp",
},
.probe = imx_dsp_probe,
.remove = imx_dsp_remove,
};
builtin_platform_driver(imx_dsp_driver);
MODULE_AUTHOR("Daniel Baluta <daniel.baluta@nxp.com>");
MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
MODULE_LICENSE("GPL v2");

View File

@ -0,0 +1,67 @@
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright 2019 NXP
*
* Header file for the DSP IPC implementation
*/
#ifndef _IMX_DSP_IPC_H
#define _IMX_DSP_IPC_H
#include <linux/device.h>
#include <linux/types.h>
#include <linux/mailbox_client.h>
#define DSP_MU_CHAN_NUM 4
struct imx_dsp_chan {
struct imx_dsp_ipc *ipc;
struct mbox_client cl;
struct mbox_chan *ch;
char *name;
int idx;
};
struct imx_dsp_ops {
void (*handle_reply)(struct imx_dsp_ipc *ipc);
void (*handle_request)(struct imx_dsp_ipc *ipc);
};
struct imx_dsp_ipc {
/* Host <-> DSP communication uses 2 txdb and 2 rxdb channels */
struct imx_dsp_chan chans[DSP_MU_CHAN_NUM];
struct device *dev;
struct imx_dsp_ops *ops;
void *private_data;
};
static inline void imx_dsp_set_data(struct imx_dsp_ipc *ipc, void *data)
{
if (!ipc)
return;
ipc->private_data = data;
}
static inline void *imx_dsp_get_data(struct imx_dsp_ipc *ipc)
{
if (!ipc)
return NULL;
return ipc->private_data;
}
#if IS_ENABLED(CONFIG_IMX_DSP)
int imx_dsp_ring_doorbell(struct imx_dsp_ipc *dsp, unsigned int chan_idx);
#else
static inline int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc,
unsigned int chan_idx)
{
return -ENOTSUPP;
}
#endif
#endif /* _IMX_DSP_IPC_H */