Re: [PATCH v2 1/2] firmware: imx: Add DSP IPC protocol interface

From: Daniel Baluta
Date: Thu Jul 18 2019 - 02:40:28 EST

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I just made some minor changes and will send the patch right now.
Shawn please skip this.

On Tue, Jul 9, 2019 at 3:02 PM Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> wrote:
>
> On Tue, Jul 09, 2019 at 08:48:20AM +0300, Daniel Baluta wrote:
> > Hi Oleksij,
> >
> > Any comments on this?
>
> Looks good for me. All my suggestions was fixed.
>
> Reviewed-by: <o.rempel@xxxxxxxxxxxxxx>
>
> > On Thu, Jun 27, 2019 at 11:14 AM Daniel Baluta <daniel.baluta@xxxxxxx> wrote:
> > >
> > > 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 driver 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 driver 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 drivers 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 driver on
> > > notification arrival from DSP.
> > >
> > > Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxx>
> > > ---
> > > drivers/firmware/imx/Kconfig | 11 +++
> > > drivers/firmware/imx/Makefile | 1 +
> > > drivers/firmware/imx/imx-dsp.c | 142 +++++++++++++++++++++++++++++++
> > > include/linux/firmware/imx/dsp.h | 67 +++++++++++++++
> > > 4 files changed, 221 insertions(+)
> > > create mode 100644 drivers/firmware/imx/imx-dsp.c
> > > create mode 100644 include/linux/firmware/imx/dsp.h
> > >
> > > diff --git a/drivers/firmware/imx/Kconfig b/drivers/firmware/imx/Kconfig
> > > index 42b566f8903f..ddb241708c31 100644
> > > --- a/drivers/firmware/imx/Kconfig
> > > +++ b/drivers/firmware/imx/Kconfig
> > > @@ -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 CPU (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
> > > diff --git a/drivers/firmware/imx/Makefile b/drivers/firmware/imx/Makefile
> > > index 802c4ad8e8f9..08bc9ddfbdfb 100644
> > > --- a/drivers/firmware/imx/Makefile
> > > +++ b/drivers/firmware/imx/Makefile
> > > @@ -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
> > > diff --git a/drivers/firmware/imx/imx-dsp.c b/drivers/firmware/imx/imx-dsp.c
> > > new file mode 100644
> > > index 000000000000..c4d34a2fbff3
> > > --- /dev/null
> > > +++ b/drivers/firmware/imx/imx-dsp.c
> > > @@ -0,0 +1,142 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * Copyright 2019 NXP
> > > + * Author: Daniel Baluta <daniel.baluta@xxxxxxx>
> > > + *
> > > + * 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;
> > > +
> > > + 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 const struct of_device_id imx_dsp_match[] = {
> > > + { .compatible = "fsl,imx8qxp-dsp", },
> > > + { /* Sentinel */ }
> > > +};
> > > +
> > > +static struct platform_driver imx_dsp_driver = {
> > > + .driver = {
> > > + .name = "imx-dsp",
> > > + .of_match_table = imx_dsp_match,
> > > + },
> > > + .probe = imx_dsp_probe,
> > > +};
> > > +builtin_platform_driver(imx_dsp_driver);
> > > +
> > > +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@xxxxxxx>");
> > > +MODULE_DESCRIPTION("IMX DSP IPC protocol driver");
> > > +MODULE_LICENSE("GPL v2");
> > > diff --git a/include/linux/firmware/imx/dsp.h b/include/linux/firmware/imx/dsp.h
> > > new file mode 100644
> > > index 000000000000..7562099c9e46
> > > --- /dev/null
> > > +++ b/include/linux/firmware/imx/dsp.h
> > > @@ -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 */
> > > --
> > > 2.17.1
> > >
> >
>
> --
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