[PATCH v3 4/9] PCI: epf-mhi: Add support for handling D-state notify from EPC

[PATCH v3 4/9] PCI: epf-mhi: Add support for handling D-state notify from EPC

[Krishna chaitanya chundru]

Add support for handling D-state notify for MHI EPF.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/pci/endpoint/functions/pci-epf-mhi.c | 11 +++++++++++
 include/linux/mhi_ep.h                       |  3 +++
 2 files changed, 14 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
index 9c1f5a1..631eb2f7 100644
--- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -339,6 +339,16 @@ static int pci_epf_mhi_bme(struct pci_epf *epf)
 	return 0;
 }
 
+static int pci_epf_mhi_dstate_notify(struct pci_epf *epf, pci_power_t state)
+{
+	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
+	struct mhi_ep_cntrl *mhi_cntrl = &epf_mhi->mhi_cntrl;
+
+	mhi_cntrl->dstate = state;
+
+	return 0;
+}
+
 static int pci_epf_mhi_bind(struct pci_epf *epf)
 {
 	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
@@ -394,6 +404,7 @@ static struct pci_epc_event_ops pci_epf_mhi_event_ops = {
 	.link_up = pci_epf_mhi_link_up,
 	.link_down = pci_epf_mhi_link_down,
 	.bme = pci_epf_mhi_bme,
+	.dstate_notify = pci_epf_mhi_dstate_notify,
 };
 
 static int pci_epf_mhi_probe(struct pci_epf *epf,
diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
index f198a8a..c3a0685 100644
--- a/include/linux/mhi_ep.h
+++ b/include/linux/mhi_ep.h
@@ -8,6 +8,7 @@
 
 #include <linux/dma-direction.h>
 #include <linux/mhi.h>
+#include <linux/pci.h>
 
 #define MHI_EP_DEFAULT_MTU 0x8000
 
@@ -139,6 +140,8 @@ struct mhi_ep_cntrl {
 
 	enum mhi_state mhi_state;
 
+	pci_power_t dstate;
+
 	u32 max_chan;
 	u32 mru;
 	u32 event_rings;
-- 
2.7.4

[PATCH v3 8/9] PCI: epf-mhi: Add wakeup host op

[Krishna chaitanya chundru]

Add wakeup host op for MHI EPF.
If the D-state is in D3cold toggle wake signal, otherwise send PME.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/pci/endpoint/functions/pci-epf-mhi.c | 17 +++++++++++++++++
 include/linux/mhi_ep.h                       |  1 +
 2 files changed, 18 insertions(+)

diff --git a/drivers/pci/endpoint/functions/pci-epf-mhi.c b/drivers/pci/endpoint/functions/pci-epf-mhi.c
index 631eb2f7..d84f869 100644
--- a/drivers/pci/endpoint/functions/pci-epf-mhi.c
+++ b/drivers/pci/endpoint/functions/pci-epf-mhi.c
@@ -237,6 +237,22 @@ static int pci_epf_mhi_write_to_host(struct mhi_ep_cntrl *mhi_cntrl,
 	return 0;
 }
 
+static int pci_epf_mhi_wakeup_host(struct mhi_ep_cntrl *mhi_cntrl)
+{
+	struct pci_epf_mhi *epf_mhi = to_epf_mhi(mhi_cntrl);
+	struct pci_epf *epf = epf_mhi->epf;
+	enum pci_epc_wakeup_host_type type;
+	struct pci_epc *epc = epf->epc;
+	int ret;
+
+	type = PCI_WAKEUP_SEND_PME;
+	if (mhi_cntrl->dstate == PCI_D3cold)
+		type = PCI_WAKEUP_TOGGLE_WAKE;
+
+	return pci_epc_wakeup_host(epc, epf->func_no, epf->vfunc_no, type);
+
+}
+
 static int pci_epf_mhi_core_init(struct pci_epf *epf)
 {
 	struct pci_epf_mhi *epf_mhi = epf_get_drvdata(epf);
@@ -293,6 +309,7 @@ static int pci_epf_mhi_link_up(struct pci_epf *epf)
 	mhi_cntrl->unmap_free = pci_epf_mhi_unmap_free;
 	mhi_cntrl->read_from_host = pci_epf_mhi_read_from_host;
 	mhi_cntrl->write_to_host = pci_epf_mhi_write_to_host;
+	mhi_cntrl->wakeup_host = pci_epf_mhi_wakeup_host;
 
 	/* Register the MHI EP controller */
 	ret = mhi_ep_register_controller(mhi_cntrl, info->config);
diff --git a/include/linux/mhi_ep.h b/include/linux/mhi_ep.h
index c3a0685..e353c429 100644
--- a/include/linux/mhi_ep.h
+++ b/include/linux/mhi_ep.h
@@ -137,6 +137,7 @@ struct mhi_ep_cntrl {
 			   void __iomem *virt, size_t size);
 	int (*read_from_host)(struct mhi_ep_cntrl *mhi_cntrl, u64 from, void *to, size_t size);
 	int (*write_to_host)(struct mhi_ep_cntrl *mhi_cntrl, void *from, u64 to, size_t size);
+	int (*wakeup_host)(struct mhi_ep_cntrl *mhi_cntrl);
 
 	enum mhi_state mhi_state;
 
-- 
2.7.4

[PATCH v3 9/9] bus: mhi: ep: wake up host is the MHI state is in M3

[Krishna chaitanya chundru]

If the MHI state is in M3 then the most probably the host kept the
device in D3 hot or D3 cold, due to that endpoint transctions will not
be read by the host, so endpoint wakes up host to bring the host to D0
which eventually bring back the MHI state to M0.

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 6008818..46a8a3c 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -25,6 +25,27 @@ 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 bool 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 */
+	do {
+		msleep(M0_WAIT_DELAY_MS);
+		mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset);
+		count++;
+	} while (state != MHI_STATE_M0 && count < M0_WAIT_COUNT);
+
+	if (state != MHI_STATE_M0)
+		return false;
+
+	return true;
+}
+
 static int mhi_ep_send_event(struct mhi_ep_cntrl *mhi_cntrl, u32 ring_idx,
 			     struct mhi_ring_element *el, bool bei)
 {
@@ -464,6 +485,13 @@ int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, struct sk_buff *skb)
 	buf_left = skb->len;
 	ring = &mhi_cntrl->mhi_chan[mhi_chan->chan].ring;
 
+	if (mhi_cntrl->mhi_state == MHI_STATE_M3) {
+		if (mhi_ep_wake_host(mhi_cntrl)) {
+			dev_err(dev, "Failed to wakeup host\n");
+			return -ENODEV;
+		}
+	}
+
 	mutex_lock(&mhi_chan->lock);
 
 	do {
-- 
2.7.4

Re: [PATCH v3 9/9] bus: mhi: ep: wake up host is the MHI state is in M3

[Dan Carpenter]

On Fri, Jul 07, 2023 at 04:33:56PM +0530, Krishna chaitanya chundru wrote:
> If the MHI state is in M3 then the most probably the host kept the
> device in D3 hot or D3 cold, due to that endpoint transctions will not
> be read by the host, so endpoint wakes up host to bring the host to D0
> which eventually bring back the MHI state to M0.
> 
> 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 6008818..46a8a3c 100644
> --- a/drivers/bus/mhi/ep/main.c
> +++ b/drivers/bus/mhi/ep/main.c
> @@ -25,6 +25,27 @@ 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 bool 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 */
> +	do {
> +		msleep(M0_WAIT_DELAY_MS);
> +		mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset);
> +		count++;
> +	} while (state != MHI_STATE_M0 && count < M0_WAIT_COUNT);
> +
>+	if (state != MHI_STATE_M0)
>+		return false;

Functions which return false on success are an abomination.  Also
boolean functions should be named for the question they answer such as
access_ok() or has_feature() etc.

Actually, I think it's the caller which is wrong.  This returns true on
success and false on failure.  But the caller assumes true is failure.
It suggests that this has not been tested.

> +
> +	return true;
> +}

Write it like this:

static int mhi_ep_wake_host(struct mhi_ep_cntrl *mhi_cntrl)
{
	enum mhi_state state;
	bool mhi_reset;
	int count = 0;

	mhi_cntrl->wakeup_host(mhi_cntrl);

	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)
>  {
> @@ -464,6 +485,13 @@ int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, struct sk_buff *skb)
>  	buf_left = skb->len;
>  	ring = &mhi_cntrl->mhi_chan[mhi_chan->chan].ring;
>  
> +	if (mhi_cntrl->mhi_state == MHI_STATE_M3) {
> +		if (mhi_ep_wake_host(mhi_cntrl)) {
> +			dev_err(dev, "Failed to wakeup host\n");
> +			return -ENODEV;
> +		}

Then this becomes:

	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");
			return ret;
		}
	}

regards,
dan carpenter

Re: [PATCH v3 9/9] bus: mhi: ep: wake up host is the MHI state is in M3

[Bjorn Helgaas]

On Fri, Jul 07, 2023 at 02:41:57PM +0300, Dan Carpenter wrote:
> On Fri, Jul 07, 2023 at 04:33:56PM +0530, Krishna chaitanya chundru wrote:
> > If the MHI state is in M3 then the most probably the host kept the
> > device in D3 hot or D3 cold, due to that endpoint transctions will not
> > be read by the host, so endpoint wakes up host to bring the host to D0
> > which eventually bring back the MHI state to M0.
> > 
> > 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 6008818..46a8a3c 100644
> > --- a/drivers/bus/mhi/ep/main.c
> > +++ b/drivers/bus/mhi/ep/main.c
> > @@ -25,6 +25,27 @@ 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 bool 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 */
> > +	do {
> > +		msleep(M0_WAIT_DELAY_MS);
> > +		mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset);
> > +		count++;
> > +	} while (state != MHI_STATE_M0 && count < M0_WAIT_COUNT);
> > +
> >+	if (state != MHI_STATE_M0)
> >+		return false;
> 
> Functions which return false on success are an abomination.  Also
> boolean functions should be named for the question they answer such
> as access_ok() or has_feature() etc.

+1.  Also nice if boolean functions do not have side effects, so in
this case, where mhi_ep_wake_host() *does* something that might fail,
I think "return 0 for success or negative error value" is easier to
read.

> Write it like this:
> 
> static int mhi_ep_wake_host(struct mhi_ep_cntrl *mhi_cntrl)
> {
> 	enum mhi_state state;
> 	bool mhi_reset;
> 	int count = 0;
> 
> 	mhi_cntrl->wakeup_host(mhi_cntrl);
> 
> 	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;
> }

Re: [PATCH v3 9/9] bus: mhi: ep: wake up host is the MHI state is in M3

[Krishna Chaitanya Chundru]

On 7/7/2023 8:42 PM, Bjorn Helgaas wrote:
> On Fri, Jul 07, 2023 at 02:41:57PM +0300, Dan Carpenter wrote:
>> On Fri, Jul 07, 2023 at 04:33:56PM +0530, Krishna chaitanya chundru wrote:
>>> If the MHI state is in M3 then the most probably the host kept the
>>> device in D3 hot or D3 cold, due to that endpoint transctions will not
>>> be read by the host, so endpoint wakes up host to bring the host to D0
>>> which eventually bring back the MHI state to M0.
>>>
>>> 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 6008818..46a8a3c 100644
>>> --- a/drivers/bus/mhi/ep/main.c
>>> +++ b/drivers/bus/mhi/ep/main.c
>>> @@ -25,6 +25,27 @@ 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 bool 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 */
>>> +	do {
>>> +		msleep(M0_WAIT_DELAY_MS);
>>> +		mhi_ep_mmio_get_mhi_state(mhi_cntrl, &state, &mhi_reset);
>>> +		count++;
>>> +	} while (state != MHI_STATE_M0 && count < M0_WAIT_COUNT);
>>> +
>>> +	if (state != MHI_STATE_M0)
>>> +		return false;
>> Functions which return false on success are an abomination.  Also
>> boolean functions should be named for the question they answer such
>> as access_ok() or has_feature() etc.
> +1.  Also nice if boolean functions do not have side effects, so in
> this case, where mhi_ep_wake_host() *does* something that might fail,
> I think "return 0 for success or negative error value" is easier to
> read.

sure Dan and Bjorn I will replace bool with int return type as suggested 
in the next patch series.

- KC

>> Write it like this:
>>
>> static int mhi_ep_wake_host(struct mhi_ep_cntrl *mhi_cntrl)
>> {
>> 	enum mhi_state state;
>> 	bool mhi_reset;
>> 	int count = 0;
>>
>> 	mhi_cntrl->wakeup_host(mhi_cntrl);
>>
>> 	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;
>> }