Hi Daniel, please, see my review inline.
On Fri, Jun 14, 2019 at 04:16:49PM +0800, [email protected] wrote: > From: Daniel Baluta <[email protected]> > > 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 <[email protected]> > --- > drivers/firmware/imx/Kconfig | 11 ++ > drivers/firmware/imx/Makefile | 1 + > drivers/firmware/imx/imx-dsp.c | 167 +++++++++++++++++++++++++++++++ > include/linux/firmware/imx/dsp.h | 61 +++++++++++ > 4 files changed, 240 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..383996b679a8 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..953fd364ad76 > --- /dev/null > +++ b/drivers/firmware/imx/imx-dsp.c > @@ -0,0 +1,167 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright 2018 NXP > + * Author: Daniel Baluta <[email protected]> > + * > + * 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> > + > +static struct imx_dsp_ipc *imx_dsp_handle; > + > +/* > + * Get the default handle used by DSP > + */ > +int imx_dsp_get_handle(struct imx_dsp_ipc **ipc) > +{ > + if (!imx_dsp_handle) > + return -EPROBE_DEFER; > + > + *ipc = imx_dsp_handle; > + return 0; > +} > +EXPORT_SYMBOL(imx_dsp_get_handle); Please, extract needed device or handle form device tree. The consumer should pars own device tree node and get the phandle to the dsp node. > +void imx_dsp_set_data(struct imx_dsp_ipc *ipc, void *data) > +{ > + if (!ipc) > + return; > + > + ipc->private_data = data; > +} > +EXPORT_SYMBOL(imx_dsp_set_data); > + > +void *imx_dsp_get_data(struct imx_dsp_ipc *ipc) > +{ > + if (!ipc) > + return NULL; > + > + return ipc->private_data; > +} > +EXPORT_SYMBOL(imx_dsp_get_data); > + > +/* > + * 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; On this test idx may overflow. DSP_MU_CHAN_NUM is 4, means idx can be: 0, 1, 2, 3. In you case idx == 4 is allowed, so the caller will be able to corrupt the rest of imx_dsp_ipc struct. > + 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; > + > + 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); > + return ret; On the error you will leak the memory previously allocated chan_name. And you should call mbox_free_channel() for each previously registered channel in this loop. > + } > + > + 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; > + > + imx_dsp_handle = dsp_ipc; bad idea. What happens if multiple dsp nodes are registered in the device tree? > + dev_info(dev, "NXP i.MX DSP IPC initialized\n"); > + > + return devm_of_platform_populate(dev); > +} > + > +static const struct of_device_id imx_dsp_match[] = { > + { .compatible = "fsl,imx-dsp", }, i would prefer to have chip name in the compatible. For example fsl,imx8qm-dsp. Soon or later we will need to define some quirks for on or another chip. > + { /* 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 <[email protected]>"); > +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..75637d8fab34 > --- /dev/null > +++ b/include/linux/firmware/imx/dsp.h > @@ -0,0 +1,61 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > +/* > + * Copyright 2018 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; > + 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; > +}; > + > +#if IS_ENABLED(CONFIG_IMX_DSP) > + > +int imx_dsp_ring_doorbell(struct imx_dsp_ipc *dsp, unsigned int chan_idx); > +int imx_dsp_get_handle(struct imx_dsp_ipc **ipc); > +void imx_dsp_set_data(struct imx_dsp_ipc *ipc, void *data); > +void *imx_dsp_get_data(struct imx_dsp_ipc *ipc); > + > +#else > + > +static inline int imx_dsp_get_handle(struct imx_dsp_ipc **ipc) > +{ > + return -EIO; please, use -ENOTSUPP instead. > +} > + > +static inline int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc, > + unsigned int chan_idx) > +{ > + return -EIO; > +} > + > +void imx_dsp_set_data(struct imx_dsp_ipc *ipc, void *data) { } > +void *imx_dsp_get_data(struct imx_dsp_ipc *ipc) { return NULL; } > + > +#endif > +#endif /* _IMX_DSP_IPC_H */ > -- > 2.17.1 > > -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
