On Thu, Dec 11, 2025 at 01:37:40PM +0530, Sivareddy Surasani wrote:
> From: Vivek Pernamitta <vivek.pernamitta@oss.qualcomm.com>
>
> If a device reports an error on any channel, it sends a
> CH_ERROR_EVENT over the control event ring. Update the host to
> parse the entire channel list, check the channel context ring
> for CH_STATE_ERROR, and notify the client. This enables the
> client driver to take appropriate action as needed.
>
What scenarios could lead to the device sending this channel error event?
> Signed-off-by: Vivek Pernamitta <vivek.pernamitta@oss.qualcomm.com>
> Signed-off-by: Sivareddy Surasani <sivareddy.surasani@oss.qualcomm.com>
> ---
> drivers/bus/mhi/common.h | 1 +
> drivers/bus/mhi/host/main.c | 24 ++++++++++++++++++++++++
> include/linux/mhi.h | 2 ++
> 3 files changed, 27 insertions(+)
>
> diff --git a/drivers/bus/mhi/common.h b/drivers/bus/mhi/common.h
> index 31ff4d2e6eba..3b3ecbc6169f 100644
> --- a/drivers/bus/mhi/common.h
> +++ b/drivers/bus/mhi/common.h
> @@ -230,6 +230,7 @@ enum mhi_pkt_type {
> MHI_PKT_TYPE_TX_EVENT = 0x22,
> MHI_PKT_TYPE_RSC_TX_EVENT = 0x28,
> MHI_PKT_TYPE_EE_EVENT = 0x40,
> + MHI_PKT_TYPE_CH_ERROR_EVENT = 0x41,
> MHI_PKT_TYPE_TSYNC_EVENT = 0x48,
> MHI_PKT_TYPE_BW_REQ_EVENT = 0x50,
> MHI_PKT_TYPE_STALE_EVENT, /* internal event */
> diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c
> index 53bb93da4017..9772fb13400c 100644
> --- a/drivers/bus/mhi/host/main.c
> +++ b/drivers/bus/mhi/host/main.c
> @@ -798,6 +798,27 @@ static int parse_rsc_event(struct mhi_controller *mhi_cntrl,
> return 0;
> }
>
> +static void mhi_process_channel_error(struct mhi_controller *mhi_cntrl)
> +{
> + struct mhi_chan *mhi_chan;
> + struct mhi_chan_ctxt *chan_ctxt;
> + struct mhi_device *mhi_dev;
> + int i;
> +
> + mhi_chan = mhi_cntrl->mhi_chan;
> + for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) {
> + chan_ctxt = &mhi_cntrl->mhi_ctxt->chan_ctxt[mhi_chan->chan];
> +
> + if ((chan_ctxt->chcfg & CHAN_CTX_CHSTATE_MASK) == MHI_CH_STATE_ERROR) {
> + dev_err(&mhi_cntrl->mhi_dev->dev,
You should use the channel mhi_dev.
> + "ch_id:%d is moved to error state by device", mhi_chan->chan);
"Channel entered error state"
- Mani
> + mhi_dev = mhi_chan->mhi_dev;
> + if (mhi_dev)
> + mhi_notify(mhi_dev, MHI_CB_CHANNEL_ERROR);
> + }
> + }
> +}
> +
> static void mhi_process_cmd_completion(struct mhi_controller *mhi_cntrl,
> struct mhi_ring_element *tre)
> {
> @@ -961,6 +982,9 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
>
> break;
> }
> + case MHI_PKT_TYPE_CH_ERROR_EVENT:
> + mhi_process_channel_error(mhi_cntrl);
> + break;
> case MHI_PKT_TYPE_TX_EVENT:
> chan = MHI_TRE_GET_EV_CHID(local_rp);
>
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index 926a20835467..66fd83bed306 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -34,6 +34,7 @@ struct mhi_buf_info;
> * @MHI_CB_SYS_ERROR: MHI device entered error state (may recover)
> * @MHI_CB_FATAL_ERROR: MHI device entered fatal error state
> * @MHI_CB_BW_REQ: Received a bandwidth switch request from device
> + * @MHI_CB_CHANNEL_ERROR: MHI channel entered error state from device
> */
> enum mhi_callback {
> MHI_CB_IDLE,
> @@ -45,6 +46,7 @@ enum mhi_callback {
> MHI_CB_SYS_ERROR,
> MHI_CB_FATAL_ERROR,
> MHI_CB_BW_REQ,
> + MHI_CB_CHANNEL_ERROR,
> };
>
> /**
>
> --
> 2.34.1
>
--
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