1. Patchew
  2. linux
  3. View series

[PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities

Hans Zhang posted 1 patch 3 months, 3 weeks ago 
.../pci/controller/dwc/pcie-designware-ep.c   | 39 +++++++------------
1 file changed, 14 insertions(+), 25 deletions(-)
[PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities
Posted by Hans Zhang 3 months, 3 weeks ago 
Use the PCI core is now exposing generic macros for the host bridges to
search for the PCIe capabilities, make use of them in the DWC EP driver.

Signed-off-by: Hans Zhang <18255117159@163.com>
---
- Submissions based on the following patches:
https://patchwork.kernel.org/project/linux-pci/patch/20250607161405.808585-1-18255117159@163.com/

Recently, I checked the code and found that there are still some areas that can be further optimized.
The above series of patches has been around for a long time, so I'm sending this one out for review
as a separate patch.
---
 .../pci/controller/dwc/pcie-designware-ep.c   | 39 +++++++------------
 1 file changed, 14 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 0ae54a94809b..9f1880cc1925 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -69,37 +69,26 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
 }
 EXPORT_SYMBOL_GPL(dw_pcie_ep_reset_bar);
 
-static u8 __dw_pcie_ep_find_next_cap(struct dw_pcie_ep *ep, u8 func_no,
-				     u8 cap_ptr, u8 cap)
+static int dw_pcie_ep_read_cfg(void *priv, u8 func_no, int where, int size, u32 *val)
 {
-	u8 cap_id, next_cap_ptr;
-	u16 reg;
-
-	if (!cap_ptr)
-		return 0;
-
-	reg = dw_pcie_ep_readw_dbi(ep, func_no, cap_ptr);
-	cap_id = (reg & 0x00ff);
-
-	if (cap_id > PCI_CAP_ID_MAX)
-		return 0;
-
-	if (cap_id == cap)
-		return cap_ptr;
+	struct dw_pcie_ep *ep = priv;
+
+	if (size == 4)
+		*val = dw_pcie_ep_readl_dbi(ep, func_no, where);
+	else if (size == 2)
+		*val = dw_pcie_ep_readw_dbi(ep, func_no, where);
+	else if (size == 1)
+		*val = dw_pcie_ep_readb_dbi(ep, func_no, where);
+	else
+		return PCIBIOS_BAD_REGISTER_NUMBER;
 
-	next_cap_ptr = (reg & 0xff00) >> 8;
-	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
+	return PCIBIOS_SUCCESSFUL;
 }
 
 static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8 func_no, u8 cap)
 {
-	u8 next_cap_ptr;
-	u16 reg;
-
-	reg = dw_pcie_ep_readw_dbi(ep, func_no, PCI_CAPABILITY_LIST);
-	next_cap_ptr = (reg & 0x00ff);
-
-	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
+	return PCI_FIND_NEXT_CAP_TTL(dw_pcie_ep_read_cfg, PCI_CAPABILITY_LIST,
+				     cap, ep, func_no);
 }
 
 /**

base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
-- 
2.25.1
Re: [PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities
Posted by Manivannan Sadhasivam 1 month, 3 weeks ago 
On Mon, Jun 16, 2025 at 11:25:15PM GMT, Hans Zhang wrote:
> Use the PCI core is now exposing generic macros for the host bridges to
> search for the PCIe capabilities, make use of them in the DWC EP driver.
> 
> Signed-off-by: Hans Zhang <18255117159@163.com>

Please send it together with the dependent series.

- Mani

> ---
> - Submissions based on the following patches:
> https://patchwork.kernel.org/project/linux-pci/patch/20250607161405.808585-1-18255117159@163.com/
> 
> Recently, I checked the code and found that there are still some areas that can be further optimized.
> The above series of patches has been around for a long time, so I'm sending this one out for review
> as a separate patch.
> ---
>  .../pci/controller/dwc/pcie-designware-ep.c   | 39 +++++++------------
>  1 file changed, 14 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 0ae54a94809b..9f1880cc1925 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -69,37 +69,26 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
>  }
>  EXPORT_SYMBOL_GPL(dw_pcie_ep_reset_bar);
>  
> -static u8 __dw_pcie_ep_find_next_cap(struct dw_pcie_ep *ep, u8 func_no,
> -				     u8 cap_ptr, u8 cap)
> +static int dw_pcie_ep_read_cfg(void *priv, u8 func_no, int where, int size, u32 *val)
>  {
> -	u8 cap_id, next_cap_ptr;
> -	u16 reg;
> -
> -	if (!cap_ptr)
> -		return 0;
> -
> -	reg = dw_pcie_ep_readw_dbi(ep, func_no, cap_ptr);
> -	cap_id = (reg & 0x00ff);
> -
> -	if (cap_id > PCI_CAP_ID_MAX)
> -		return 0;
> -
> -	if (cap_id == cap)
> -		return cap_ptr;
> +	struct dw_pcie_ep *ep = priv;
> +
> +	if (size == 4)
> +		*val = dw_pcie_ep_readl_dbi(ep, func_no, where);
> +	else if (size == 2)
> +		*val = dw_pcie_ep_readw_dbi(ep, func_no, where);
> +	else if (size == 1)
> +		*val = dw_pcie_ep_readb_dbi(ep, func_no, where);
> +	else
> +		return PCIBIOS_BAD_REGISTER_NUMBER;
>  
> -	next_cap_ptr = (reg & 0xff00) >> 8;
> -	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
> +	return PCIBIOS_SUCCESSFUL;
>  }
>  
>  static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8 func_no, u8 cap)
>  {
> -	u8 next_cap_ptr;
> -	u16 reg;
> -
> -	reg = dw_pcie_ep_readw_dbi(ep, func_no, PCI_CAPABILITY_LIST);
> -	next_cap_ptr = (reg & 0x00ff);
> -
> -	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
> +	return PCI_FIND_NEXT_CAP_TTL(dw_pcie_ep_read_cfg, PCI_CAPABILITY_LIST,
> +				     cap, ep, func_no);
>  }
>  
>  /**
> 
> base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
> -- 
> 2.25.1
> 

-- 
மணிவண்ணன் சதாசிவம்
Re: [PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities
Posted by Hans Zhang 1 month, 3 weeks ago 

On 2025/8/19 22:14, Manivannan Sadhasivam wrote:
> On Mon, Jun 16, 2025 at 11:25:15PM GMT, Hans Zhang wrote:
>> Use the PCI core is now exposing generic macros for the host bridges to
>> search for the PCIe capabilities, make use of them in the DWC EP driver.
>>
>> Signed-off-by: Hans Zhang <18255117159@163.com>
> 
> Please send it together with the dependent series.
> 

Dear Mani,

I'll send it out right away later.

Best regards,
Hans


> 
>> ---
>> - Submissions based on the following patches:
>> https://patchwork.kernel.org/project/linux-pci/patch/20250607161405.808585-1-18255117159@163.com/
>>
>> Recently, I checked the code and found that there are still some areas that can be further optimized.
>> The above series of patches has been around for a long time, so I'm sending this one out for review
>> as a separate patch.
>> ---
>>   .../pci/controller/dwc/pcie-designware-ep.c   | 39 +++++++------------
>>   1 file changed, 14 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
>> index 0ae54a94809b..9f1880cc1925 100644
>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
>> @@ -69,37 +69,26 @@ void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
>>   }
>>   EXPORT_SYMBOL_GPL(dw_pcie_ep_reset_bar);
>>   
>> -static u8 __dw_pcie_ep_find_next_cap(struct dw_pcie_ep *ep, u8 func_no,
>> -				     u8 cap_ptr, u8 cap)
>> +static int dw_pcie_ep_read_cfg(void *priv, u8 func_no, int where, int size, u32 *val)
>>   {
>> -	u8 cap_id, next_cap_ptr;
>> -	u16 reg;
>> -
>> -	if (!cap_ptr)
>> -		return 0;
>> -
>> -	reg = dw_pcie_ep_readw_dbi(ep, func_no, cap_ptr);
>> -	cap_id = (reg & 0x00ff);
>> -
>> -	if (cap_id > PCI_CAP_ID_MAX)
>> -		return 0;
>> -
>> -	if (cap_id == cap)
>> -		return cap_ptr;
>> +	struct dw_pcie_ep *ep = priv;
>> +
>> +	if (size == 4)
>> +		*val = dw_pcie_ep_readl_dbi(ep, func_no, where);
>> +	else if (size == 2)
>> +		*val = dw_pcie_ep_readw_dbi(ep, func_no, where);
>> +	else if (size == 1)
>> +		*val = dw_pcie_ep_readb_dbi(ep, func_no, where);
>> +	else
>> +		return PCIBIOS_BAD_REGISTER_NUMBER;
>>   
>> -	next_cap_ptr = (reg & 0xff00) >> 8;
>> -	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
>> +	return PCIBIOS_SUCCESSFUL;
>>   }
>>   
>>   static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8 func_no, u8 cap)
>>   {
>> -	u8 next_cap_ptr;
>> -	u16 reg;
>> -
>> -	reg = dw_pcie_ep_readw_dbi(ep, func_no, PCI_CAPABILITY_LIST);
>> -	next_cap_ptr = (reg & 0x00ff);
>> -
>> -	return __dw_pcie_ep_find_next_cap(ep, func_no, next_cap_ptr, cap);
>> +	return PCI_FIND_NEXT_CAP_TTL(dw_pcie_ep_read_cfg, PCI_CAPABILITY_LIST,
>> +				     cap, ep, func_no);
>>   }
>>   
>>   /**
>>
>> base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
>> -- 
>> 2.25.1
>>
>
Re: [PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities
Posted by kernel test robot 3 months, 3 weeks ago 
Hi Hans,

kernel test robot noticed the following build errors:

[auto build test ERROR on 19272b37aa4f83ca52bdf9c16d5d81bdd1354494]

url:    https://github.com/intel-lab-lkp/linux/commits/Hans-Zhang/PCI-endpoint-Use-common-PCI-host-bridge-APIs-for-finding-the-capabilities/20250616-232735
base:   19272b37aa4f83ca52bdf9c16d5d81bdd1354494
patch link:    https://lore.kernel.org/r/20250616152515.966480-1-18255117159%40163.com
patch subject: [PATCH] PCI: endpoint: Use common PCI host bridge APIs for finding the capabilities
config: powerpc-randconfig-r073-20250617 (https://download.01.org/0day-ci/archive/20250617/202506171435.UiUpSaqs-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project f819f46284f2a79790038e1f6649172789734ae8)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250617/202506171435.UiUpSaqs-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202506171435.UiUpSaqs-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/pci/controller/dwc/pcie-designware-ep.c:90:9: error: call to undeclared function 'PCI_FIND_NEXT_CAP_TTL'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
      90 |         return PCI_FIND_NEXT_CAP_TTL(dw_pcie_ep_read_cfg, PCI_CAPABILITY_LIST,
         |                ^
   1 error generated.


vim +/PCI_FIND_NEXT_CAP_TTL +90 drivers/pci/controller/dwc/pcie-designware-ep.c

    87	
    88	static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8 func_no, u8 cap)
    89	{
  > 90		return PCI_FIND_NEXT_CAP_TTL(dw_pcie_ep_read_cfg, PCI_CAPABILITY_LIST,
    91					     cap, ep, func_no);
    92	}
    93	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Patchew 2.1-devel-b67e4c2

© 2016 - 2025 Red Hat, Inc.