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

Frank Li
2025-12-19T16:42:58Z

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@intel.com>
> ---

Reviewed-by: Frank Li <Frank.Li@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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