[v6] Add driver support for Eswin EIC7700 SoC PCIe controller

[PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast

Posted by zhangsenchuan@eswincomputing.com 1 week, 4 days ago

From: Senchuan Zhang <zhangsenchuan@eswincomputing.com>

The ESWIN EIC7700 soc does not support enter L2 link state. Therefore add
no_suspport_L2 flag skip PME_Turn_Off broadcast and link state check code,
other driver can reuse this flag if meet the similar situation.

Signed-off-by: Yu Ning <ningyu@eswincomputing.com>
Signed-off-by: Yanghui Ou <ouyanghui@eswincomputing.com>
Signed-off-by: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
---
 drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
 drivers/pci/controller/dwc/pcie-designware.h      | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index e92513c5bda5..a203577606e5 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -1156,6 +1156,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
 		return 0;

+	if (pci->no_suspport_L2)
+		goto stop_link;
+
 	if (pci->pp.ops->pme_turn_off) {
 		pci->pp.ops->pme_turn_off(&pci->pp);
 	} else {
@@ -1182,6 +1185,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
 	 */
 	udelay(1);

+stop_link:
 	dw_pcie_stop_link(pci);
 	if (pci->pp.ops->deinit)
 		pci->pp.ops->deinit(&pci->pp);
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index e995f692a1ec..170a73299ce5 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -539,6 +539,7 @@ struct dw_pcie {
 	 * use_parent_dt_ranges to true to avoid this warning.
 	 */
 	bool			use_parent_dt_ranges;
+	bool			no_suspport_L2;
 };

 #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
--
2.25.1

Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast

Posted by Manivannan Sadhasivam 1 week, 4 days ago

On Thu, Nov 20, 2025 at 06:12:35PM +0800, zhangsenchuan@eswincomputing.com wrote:
> From: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
> 
> The ESWIN EIC7700 soc does not support enter L2 link state. Therefore add
> no_suspport_L2 flag skip PME_Turn_Off broadcast and link state check code,
> other driver can reuse this flag if meet the similar situation.
> 
> Signed-off-by: Yu Ning <ningyu@eswincomputing.com>
> Signed-off-by: Yanghui Ou <ouyanghui@eswincomputing.com>
> Signed-off-by: Senchuan Zhang <zhangsenchuan@eswincomputing.com>

Does this patch work for you?
https://lore.kernel.org/linux-pci/20251119-pci-dwc-suspend-rework-v1-1-aad104828562@oss.qualcomm.com/

- Mani

> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
>  drivers/pci/controller/dwc/pcie-designware.h      | 1 +
>  2 files changed, 5 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index e92513c5bda5..a203577606e5 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -1156,6 +1156,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>  	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
>  		return 0;
> 
> +	if (pci->no_suspport_L2)
> +		goto stop_link;
> +
>  	if (pci->pp.ops->pme_turn_off) {
>  		pci->pp.ops->pme_turn_off(&pci->pp);
>  	} else {
> @@ -1182,6 +1185,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>  	 */
>  	udelay(1);
> 
> +stop_link:
>  	dw_pcie_stop_link(pci);
>  	if (pci->pp.ops->deinit)
>  		pci->pp.ops->deinit(&pci->pp);
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index e995f692a1ec..170a73299ce5 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -539,6 +539,7 @@ struct dw_pcie {
>  	 * use_parent_dt_ranges to true to avoid this warning.
>  	 */
>  	bool			use_parent_dt_ranges;
> +	bool			no_suspport_L2;
>  };
> 
>  #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
> --
> 2.25.1
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast

Posted by zhangsenchuan 1 week, 3 days ago



> -----Original Messages-----
> From: "Manivannan Sadhasivam" <mani@kernel.org>
> Send time:Thursday, 20/11/2025 20:45:38
> To: zhangsenchuan@eswincomputing.com
> Cc: bhelgaas@google.com, krzk+dt@kernel.org, conor+dt@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, robh@kernel.org, p.zabel@pengutronix.de, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, christian.bruel@foss.st.com, mayank.rana@oss.qualcomm.com, shradha.t@samsung.com, krishna.chundru@oss.qualcomm.com, thippeswamy.havalige@amd.com, inochiama@gmail.com, ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, ouyanghui@eswincomputing.com, Frank.li@nxp.com
> Subject: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast
> 
> On Thu, Nov 20, 2025 at 06:12:35PM +0800, zhangsenchuan@eswincomputing.com wrote:
> > From: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
> > 
> > The ESWIN EIC7700 soc does not support enter L2 link state. Therefore add
> > no_suspport_L2 flag skip PME_Turn_Off broadcast and link state check code,
> > other driver can reuse this flag if meet the similar situation.
> > 
> > Signed-off-by: Yu Ning <ningyu@eswincomputing.com>
> > Signed-off-by: Yanghui Ou <ouyanghui@eswincomputing.com>
> > Signed-off-by: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
> 
> Does this patch work for you?
> https://lore.kernel.org/linux-pci/20251119-pci-dwc-suspend-rework-v1-1-aad104828562@oss.qualcomm.com/

if the PCIe link is not up, this suits me too, but if the PCIe link up, 
our hardware does not support entering the L2 link state. At this point, 
it is also necessary to skip the broadcast PME_Turn_Off message and wait
for L2 transition.

Kind regards,
Senchuan Zhang

> 
> > ---
> >  drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
> >  drivers/pci/controller/dwc/pcie-designware.h      | 1 +
> >  2 files changed, 5 insertions(+)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> > index e92513c5bda5..a203577606e5 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > @@ -1156,6 +1156,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> >  	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
> >  		return 0;
> > 
> > +	if (pci->no_suspport_L2)
> > +		goto stop_link;
> > +
> >  	if (pci->pp.ops->pme_turn_off) {
> >  		pci->pp.ops->pme_turn_off(&pci->pp);
> >  	} else {
> > @@ -1182,6 +1185,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> >  	 */
> >  	udelay(1);
> > 
> > +stop_link:
> >  	dw_pcie_stop_link(pci);
> >  	if (pci->pp.ops->deinit)
> >  		pci->pp.ops->deinit(&pci->pp);
> > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> > index e995f692a1ec..170a73299ce5 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware.h
> > +++ b/drivers/pci/controller/dwc/pcie-designware.h
> > @@ -539,6 +539,7 @@ struct dw_pcie {
> >  	 * use_parent_dt_ranges to true to avoid this warning.
> >  	 */
> >  	bool			use_parent_dt_ranges;
> > +	bool			no_suspport_L2;
> >  };
> > 
> >  #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
> > --
> > 2.25.1
> > 
> 
> -- 
> மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast

Posted by Shawn Lin 1 week, 3 days ago

在 2025/11/21 星期五 14:48, zhangsenchuan 写道:
> 
> 
> 
>> -----Original Messages-----
>> From: "Manivannan Sadhasivam" <mani@kernel.org>
>> Send time:Thursday, 20/11/2025 20:45:38
>> To: zhangsenchuan@eswincomputing.com
>> Cc: bhelgaas@google.com, krzk+dt@kernel.org, conor+dt@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, robh@kernel.org, p.zabel@pengutronix.de, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, christian.bruel@foss.st.com, mayank.rana@oss.qualcomm.com, shradha.t@samsung.com, krishna.chundru@oss.qualcomm.com, thippeswamy.havalige@amd.com, inochiama@gmail.com, ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, ouyanghui@eswincomputing.com, Frank.li@nxp.com
>> Subject: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast
>>
>> On Thu, Nov 20, 2025 at 06:12:35PM +0800, zhangsenchuan@eswincomputing.com wrote:
>>> From: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
>>>
>>> The ESWIN EIC7700 soc does not support enter L2 link state. Therefore add
>>> no_suspport_L2 flag skip PME_Turn_Off broadcast and link state check code,
>>> other driver can reuse this flag if meet the similar situation.
>>>
>>> Signed-off-by: Yu Ning <ningyu@eswincomputing.com>
>>> Signed-off-by: Yanghui Ou <ouyanghui@eswincomputing.com>
>>> Signed-off-by: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
>>
>> Does this patch work for you?
>> https://lore.kernel.org/linux-pci/20251119-pci-dwc-suspend-rework-v1-1-aad104828562@oss.qualcomm.com/
> 
> if the PCIe link is not up, this suits me too, but if the PCIe link up,
> our hardware does not support entering the L2 link state. At this point,

Per PCIe spec, 5.2 Link State Power Management:
"L2/L3 Ready transition protocol support is required.
The L2/L3 Ready state entry transition process must begin as soon as
possible following the acknowledgment of a PME_Turn_Off Message, (i.e.,
the injection of a PME_TO_Ack TLP). The Downstream component initiates
L2/L3 Ready entry by sending a PM_Enter_L23 DLLP. "

"L2 support is optional, and dependent upon the presence of auxiliary power"

I interpret it as it is mandatory support for broadcast PME_Turn_Off and
ack PME_TO_Ack, which is what the original code does. Then your IP can't
really go into L2 for whatever reasons? Will your controller be broken 
if acking PME_Turn_Off?  Otherwise we could still let L2/L3 Ready
transstion happen and leave the device in L3 to save power.


> it is also necessary to skip the broadcast PME_Turn_Off message and wait
> for L2 transition.
> 
> Kind regards,
> Senchuan Zhang
> 
>>
>>> ---
>>>   drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
>>>   drivers/pci/controller/dwc/pcie-designware.h      | 1 +
>>>   2 files changed, 5 insertions(+)
>>>
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
>>> index e92513c5bda5..a203577606e5 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
>>> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
>>> @@ -1156,6 +1156,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>>>   	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
>>>   		return 0;
>>>
>>> +	if (pci->no_suspport_L2)
>>> +		goto stop_link;
>>> +
>>>   	if (pci->pp.ops->pme_turn_off) {
>>>   		pci->pp.ops->pme_turn_off(&pci->pp);
>>>   	} else {
>>> @@ -1182,6 +1185,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
>>>   	 */
>>>   	udelay(1);
>>>
>>> +stop_link:
>>>   	dw_pcie_stop_link(pci);
>>>   	if (pci->pp.ops->deinit)
>>>   		pci->pp.ops->deinit(&pci->pp);
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
>>> index e995f692a1ec..170a73299ce5 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware.h
>>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
>>> @@ -539,6 +539,7 @@ struct dw_pcie {
>>>   	 * use_parent_dt_ranges to true to avoid this warning.
>>>   	 */
>>>   	bool			use_parent_dt_ranges;
>>> +	bool			no_suspport_L2;
>>>   };
>>>
>>>   #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
>>> --
>>> 2.25.1
>>>
>>
>> -- 
>> மணிவண்ணன் சதாசிவம்

Re: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast

Posted by zhangsenchuan 1 week ago



> -----Original Messages-----
> From: "Shawn Lin" <shawn.lin@rock-chips.com>
> Send time:Friday, 21/11/2025 15:14:51
> To: zhangsenchuan <zhangsenchuan@eswincomputing.com>
> Cc: shawn.lin@rock-chips.com, bhelgaas@google.com, krzk+dt@kernel.org, conor+dt@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, robh@kernel.org, p.zabel@pengutronix.de, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, christian.bruel@foss.st.com, mayank.rana@oss.qualcomm.com, shradha.t@samsung.com, krishna.chundru@oss.qualcomm.com, thippeswamy.havalige@amd.com, inochiama@gmail.com, ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, ouyanghui@eswincomputing.com, Frank.li@nxp.com, "Manivannan Sadhasivam" <mani@kernel.org>
> Subject: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast
> 
> 在 2025/11/21 星期五 14:48, zhangsenchuan 写道:
> > 
> > 
> > 
> >> -----Original Messages-----
> >> From: "Manivannan Sadhasivam" <mani@kernel.org>
> >> Send time:Thursday, 20/11/2025 20:45:38
> >> To: zhangsenchuan@eswincomputing.com
> >> Cc: bhelgaas@google.com, krzk+dt@kernel.org, conor+dt@kernel.org, lpieralisi@kernel.org, kwilczynski@kernel.org, robh@kernel.org, p.zabel@pengutronix.de, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, christian.bruel@foss.st.com, mayank.rana@oss.qualcomm.com, shradha.t@samsung.com, krishna.chundru@oss.qualcomm.com, thippeswamy.havalige@amd.com, inochiama@gmail.com, ningyu@eswincomputing.com, linmin@eswincomputing.com, pinkesh.vaghela@einfochips.com, ouyanghui@eswincomputing.com, Frank.li@nxp.com
> >> Subject: Re: [PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast
> >>
> >> On Thu, Nov 20, 2025 at 06:12:35PM +0800, zhangsenchuan@eswincomputing.com wrote:
> >>> From: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
> >>>
> >>> The ESWIN EIC7700 soc does not support enter L2 link state. Therefore add
> >>> no_suspport_L2 flag skip PME_Turn_Off broadcast and link state check code,
> >>> other driver can reuse this flag if meet the similar situation.
> >>>
> >>> Signed-off-by: Yu Ning <ningyu@eswincomputing.com>
> >>> Signed-off-by: Yanghui Ou <ouyanghui@eswincomputing.com>
> >>> Signed-off-by: Senchuan Zhang <zhangsenchuan@eswincomputing.com>
> >>
> >> Does this patch work for you?
> >> https://lore.kernel.org/linux-pci/20251119-pci-dwc-suspend-rework-v1-1-aad104828562@oss.qualcomm.com/
> > 
> > if the PCIe link is not up, this suits me too, but if the PCIe link up,
> > our hardware does not support entering the L2 link state. At this point,
> 
> Per PCIe spec, 5.2 Link State Power Management:
> "L2/L3 Ready transition protocol support is required.
> The L2/L3 Ready state entry transition process must begin as soon as
> possible following the acknowledgment of a PME_Turn_Off Message, (i.e.,
> the injection of a PME_TO_Ack TLP). The Downstream component initiates
> L2/L3 Ready entry by sending a PM_Enter_L23 DLLP. "
> 
> "L2 support is optional, and dependent upon the presence of auxiliary power"
> 
> I interpret it as it is mandatory support for broadcast PME_Turn_Off and
> ack PME_TO_Ack, which is what the original code does. Then your IP can't
> really go into L2 for whatever reasons? Will your controller be broken 
> if acking PME_Turn_Off?  Otherwise we could still let L2/L3 Ready
> transstion happen and leave the device in L3 to save power.

Hi, Shawn

Thank you for your comment and explanation.
Our hardware cannot broadcast PME_Turn_Off. Otherwise, the controller will
have problems, the dbi register shows that it cannot be accesseded. The link
state cannot be read in the read_poll_timeout function.

Kind regards,
Senchuan Zhang

> 
> 
> > it is also necessary to skip the broadcast PME_Turn_Off message and wait
> > for L2 transition.
> > 
> > 
> >>
> >>> ---
> >>>   drivers/pci/controller/dwc/pcie-designware-host.c | 4 ++++
> >>>   drivers/pci/controller/dwc/pcie-designware.h      | 1 +
> >>>   2 files changed, 5 insertions(+)
> >>>
> >>> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> >>> index e92513c5bda5..a203577606e5 100644
> >>> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> >>> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> >>> @@ -1156,6 +1156,9 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> >>>   	if (dw_pcie_readw_dbi(pci, offset + PCI_EXP_LNKCTL) & PCI_EXP_LNKCTL_ASPM_L1)
> >>>   		return 0;
> >>>
> >>> +	if (pci->no_suspport_L2)
> >>> +		goto stop_link;
> >>> +
> >>>   	if (pci->pp.ops->pme_turn_off) {
> >>>   		pci->pp.ops->pme_turn_off(&pci->pp);
> >>>   	} else {
> >>> @@ -1182,6 +1185,7 @@ int dw_pcie_suspend_noirq(struct dw_pcie *pci)
> >>>   	 */
> >>>   	udelay(1);
> >>>
> >>> +stop_link:
> >>>   	dw_pcie_stop_link(pci);
> >>>   	if (pci->pp.ops->deinit)
> >>>   		pci->pp.ops->deinit(&pci->pp);
> >>> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> >>> index e995f692a1ec..170a73299ce5 100644
> >>> --- a/drivers/pci/controller/dwc/pcie-designware.h
> >>> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> >>> @@ -539,6 +539,7 @@ struct dw_pcie {
> >>>   	 * use_parent_dt_ranges to true to avoid this warning.
> >>>   	 */
> >>>   	bool			use_parent_dt_ranges;
> >>> +	bool			no_suspport_L2;
> >>>   };
> >>>
> >>>   #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp)
> >>> --
> >>> 2.25.1
> >>>
> >>
> >> -- 
> >> மணிவண்ணன் சதாசிவம்

[PATCH v6 1/3] dt-bindings: PCI: eic7700: Add Eswin PCIe host controller
[PATCH v6 2/3] PCI: eic7700: Add Eswin PCIe host controller driver
[PATCH v6 3/3] PCI: dwc: Add no_suspport_L2 flag and skip PME_Turn_Off broadcast