Commit 23d89aa0 authored by Daniel Baluta's avatar Daniel Baluta Committed by Shawn Guo
Browse files

firmware: imx-dsp: Export functions to request/free channels 



In order to save power, we only need to request a channel
when the communication with the DSP active.

For this we export the following functions:
	- imx_dsp_request_channel, gets a channel with a given index
	- imx_dsp_free_channel, frees a channel with a given index

Notice that we still request channels at probe to support devices
that do not have PM callbacks implemented.

More explanations about why requesting a channel has an effect
on power savings:
 - requesting an mailbox channel will call mailbox's startup
   function.
 - startup function calls pm_runtime_get_sync which increments device
   usage count and will keep the device active. Specifically, mailbox
   clock will be always ON when a mailbox channel is requested.

Signed-off-by: default avatarDaniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: default avatarPaul Olaru <paul.olaru@nxp.com>
Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
parent 04632698

drivers/firmware/imx/imx-dsp.c

+25 −0
Original line number Diff line number Diff line
@@ -60,6 +60,31 @@ static void imx_dsp_handle_rx(struct mbox_client *c, void *msg) 
	}

}



struct mbox_chan *imx_dsp_request_channel(struct imx_dsp_ipc *dsp_ipc, int idx)

{

	struct imx_dsp_chan *dsp_chan;



	if (idx >= DSP_MU_CHAN_NUM)

		return ERR_PTR(-EINVAL);



	dsp_chan = &dsp_ipc->chans[idx];

	dsp_chan->ch = mbox_request_channel_byname(&dsp_chan->cl, dsp_chan->name);

	return dsp_chan->ch;

}

EXPORT_SYMBOL(imx_dsp_request_channel);



void imx_dsp_free_channel(struct imx_dsp_ipc *dsp_ipc, int idx)

{

	struct imx_dsp_chan *dsp_chan;



	if (idx >= DSP_MU_CHAN_NUM)

		return;



	dsp_chan = &dsp_ipc->chans[idx];

	mbox_free_channel(dsp_chan->ch);

}

EXPORT_SYMBOL(imx_dsp_free_channel);



static int imx_dsp_setup_channels(struct imx_dsp_ipc *dsp_ipc)

{

	struct device *dev = dsp_ipc->dev;

include/linux/firmware/imx/dsp.h

+10 −0
Original line number Diff line number Diff line
@@ -55,6 +55,9 @@ static inline void *imx_dsp_get_data(struct imx_dsp_ipc *ipc) 


int imx_dsp_ring_doorbell(struct imx_dsp_ipc *dsp, unsigned int chan_idx);



struct mbox_chan *imx_dsp_request_channel(struct imx_dsp_ipc *ipc, int idx);

void imx_dsp_free_channel(struct imx_dsp_ipc *ipc, int idx);



#else



static inline int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc,
@@ -63,5 +66,12 @@ static inline int imx_dsp_ring_doorbell(struct imx_dsp_ipc *ipc, 
	return -ENOTSUPP;

}



struct mbox_chan *imx_dsp_request_channel(struct imx_dsp_ipc *ipc, int idx)

{

	return ERR_PTR(-EOPNOTSUPP);

}



void imx_dsp_free_channel(struct imx_dsp_ipc *ipc, int idx) { }



#endif

#endif /* _IMX_DSP_IPC_H */

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