[PATCH 11/17] i3c: mipi-i3c-hci: Add DMA suspend and resume support

[Frank Li]

On Fri, Dec 19, 2025 at 04:45:28PM +0200, Adrian Hunter wrote:
> Introduce helper functions to suspend and resume DMA operations.  These
> are required to prepare for upcoming Runtime PM support, ensuring that
> DMA state is properly managed during power transitions.
>
> Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li at nxp.com>

>  drivers/i3c/master/mipi-i3c-hci/dma.c | 25 +++++++++++++++++++++++++
>  drivers/i3c/master/mipi-i3c-hci/hci.h |  2 ++
>  2 files changed, 27 insertions(+)
>
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
> index d0fc245f8e8f..6be97f0782d8 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dma.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
> @@ -275,6 +275,29 @@ static void hci_dma_init_rings(struct i3c_hci *hci)
>  		hci_dma_init_rh(hci, &rings->headers[i], i);
>  }
>
> +static void hci_dma_suspend(struct i3c_hci *hci)
> +{
> +	struct hci_rings_data *rings = hci->io_data;
> +	int n = rings ? rings->total : 0;
> +
> +	for (int i = 0; i < n; i++) {
> +		struct hci_rh_data *rh = &rings->headers[i];
> +
> +		rh_reg_write(INTR_SIGNAL_ENABLE, 0);
> +		rh_reg_write(RING_CONTROL, 0);
> +	}
> +
> +	i3c_hci_sync_irq_inactive(hci);
> +}
> +
> +static void hci_dma_resume(struct i3c_hci *hci)
> +{
> +	struct hci_rings_data *rings = hci->io_data;
> +
> +	if (rings)
> +		hci_dma_init_rings(hci);
> +}
> +
>  static int hci_dma_init(struct i3c_hci *hci)
>  {
>  	struct hci_rings_data *rings;
> @@ -865,4 +888,6 @@ const struct hci_io_ops mipi_i3c_hci_dma = {
>  	.request_ibi		= hci_dma_request_ibi,
>  	.free_ibi		= hci_dma_free_ibi,
>  	.recycle_ibi_slot	= hci_dma_recycle_ibi_slot,
> +	.suspend		= hci_dma_suspend,
> +	.resume			= hci_dma_resume,
>  };
> diff --git a/drivers/i3c/master/mipi-i3c-hci/hci.h b/drivers/i3c/master/mipi-i3c-hci/hci.h
> index aa8a03594e64..38f927685d3b 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/hci.h
> +++ b/drivers/i3c/master/mipi-i3c-hci/hci.h
> @@ -125,6 +125,8 @@ struct hci_io_ops {
>  				struct i3c_ibi_slot *slot);
>  	int (*init)(struct i3c_hci *hci);
>  	void (*cleanup)(struct i3c_hci *hci);
> +	void (*suspend)(struct i3c_hci *hci);
> +	void (*resume)(struct i3c_hci *hci);
>  };
>
>  extern const struct hci_io_ops mipi_i3c_hci_pio;
> --
> 2.51.0
>
>
> --
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