[PATCH v4 2/3] net: qrtr: support suspend/hibernation

[Jeff Johnson]

On 2/27/2024 6:22 PM, Baochen Qiang wrote:
> MHI devices may not be destroyed during suspend/hibernation, so need
> to unprepare/prepare MHI channels throughout the transition, this is
> done by adding suspend/resume callbacks.
> 
> The suspend callback is called in the late suspend stage, this means
> MHI channels are still alive at suspend stage, and that makes it
> possible for an MHI controller driver to communicate with others over
> those channels at suspend stage. While the resume callback is called
> in the early resume stage, for a similar reason.
> 
> Also note that we won't do unprepare/prepare when MHI device is in
> suspend state because it's pointless if MHI is only meant to go through
> a suspend/resume transition, instead of a complete power cycle.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> 
> Signed-off-by: Baochen Qiang <quic_bqiang at quicinc.com>
Reviewed-by: Jeff Johnson <quic_jjohnson at quicinc.com>