| Message ID | 20240710-wakeup_host-v6-5-ef00f31ea38d@quicinc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | PCI: EPC: Add support to wake up host from D3 states | expand |
On Wed, Jul 10, 2024 at 04:46:12PM +0530, Krishna chaitanya chundru wrote: > If the MHI state is in M3 then most probably the host kept the > device in D3 hot or D3 cold, due to that endpoint transactions will not > reach the host, endpoint needs to wakes up the host to bring the host > to D0 which eventually bring back the MHI state to M0. s/needs to wakes up/needs to wake up/ s/D3 hot/D3hot/ s/D3 cold/D3cold/ to match other uses and make grep more effective. > while queueing packets if the MHI state is in M3 wakeup host to bring > back link to M0. s/while/While/ s/MHI state is in M3/MHI is in M3/ (twice) > Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com> > --- > drivers/bus/mhi/ep/main.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c > index b3eafcf2a2c5..b8713e5c1e1a 100644 > --- a/drivers/bus/mhi/ep/main.c > +++ b/drivers/bus/mhi/ep/main.c > @@ -25,6 +25,26 @@ static DEFINE_IDA(mhi_ep_cntrl_ida); > static int mhi_ep_create_device(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id); > static int mhi_ep_destroy_device(struct device *dev, void *data); > > +static int mhi_ep_wake_host(struct mhi_ep_cntrl *mhi_cntrl) > +{ > + enum mhi_state state; > + bool mhi_reset; > + u32 count = 0; > + > + mhi_cntrl->wakeup_host(mhi_cntrl); > + > + /* Wait for Host to set the M0 state */ > + while (count++ < M0_WAIT_COUNT) { > + msleep(M0_WAIT_DELAY_MS); Tangent: the "M0_WAIT_DELAY_MS" name suggests that is the maximum delay, but it seems the actual maximum delay is M0_WAIT_DELAY_MS * M0_WAIT_COUNT. Tangent 2: unless there's a reason to be different, it would be nice to use the same loop structure as the similar delay in mhi_ep_enable(). > + mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset); > + if (state == MHI_STATE_M0) > + return 0; > + } > + > + return -ENODEV; > +}
diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c index b3eafcf2a2c5..b8713e5c1e1a 100644 --- a/drivers/bus/mhi/ep/main.c +++ b/drivers/bus/mhi/ep/main.c @@ -25,6 +25,26 @@ static DEFINE_IDA(mhi_ep_cntrl_ida); static int mhi_ep_create_device(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id); static int mhi_ep_destroy_device(struct device *dev, void *data); +static int mhi_ep_wake_host(struct mhi_ep_cntrl *mhi_cntrl) +{ + enum mhi_state state; + bool mhi_reset; + u32 count = 0; + + mhi_cntrl->wakeup_host(mhi_cntrl); + + /* Wait for Host to set the M0 state */ + while (count++ < M0_WAIT_COUNT) { + msleep(M0_WAIT_DELAY_MS); + + mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset); + if (state == MHI_STATE_M0) + return 0; + } + + return -ENODEV; +} + static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx, struct mhi_ring_element *el, bool bei) { @@ -564,6 +584,14 @@ int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, struct sk_buff *skb) mutex_lock(&mhi_chan->lock); + if (mhi_cntrl->mhi_state == MHI_STATE_M3) { + ret = mhi_ep_wake_host(mhi_cntrl); + if (ret) { + dev_err(dev, "Failed to wakeup host\n"); + goto err_exit; + } + } + do { /* Don't process the transfer ring if the channel is not in RUNNING state */ if (mhi_chan->state != MHI_CH_STATE_RUNNING) {
If the MHI state is in M3 then most probably the host kept the device in D3 hot or D3 cold, due to that endpoint transactions will not reach the host, endpoint needs to wakes up the host to bring the host to D0 which eventually bring back the MHI state to M0. while queueing packets if the MHI state is in M3 wakeup host to bring back link to M0. Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com> --- drivers/bus/mhi/ep/main.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)