[PATCH 0/2] PCI: Slot reset fixes

[PATCH 0/2] PCI: Slot reset fixes

[Manivannan Sadhasivam]

Hi,

This series fixes the issues reported for the slot reset feature merged for
v6.16.

This series is on top of dw-rockchip branch where the slot reset patches are
merged. The patches in this series can be squashed into the respective commits
since they are not merged into mainline.

- Mani

Manivannan Sadhasivam (2):
  PCI: Save and restore root port config space in
    pcibios_reset_secondary_bus()
  PCI: Rename host_bridge::reset_slot() to
    host_bridge::reset_root_port()

 drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
 drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
 drivers/pci/controller/pci-host-common.c      | 20 +++++++++----------
 drivers/pci/pci.c                             | 15 +++++++++++---
 include/linux/pci.h                           |  2 +-
 5 files changed, 31 insertions(+), 22 deletions(-)

-- 
2.43.0

[PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Manivannan Sadhasivam]

host_bridge::reset_slot() is supposed to reset the PCI root port/slot. Once
that happens, the config space content would be lost. This was reported by
Niklas on the dw-rockchip based platform where the MPS setting of the root
port was lost after the host_bridge::reset_slot() callback. Hence, save the
config space before calling the host_bridge::reset_slot() callback and
restore it afterwards.

While at it, make sure that the callback is only called for root ports by
checking if the bridge is behind the root bus.

Fixes: d5c1e1c25b37 ("PCI/ERR: Add support for resetting the slots in a platform specific way")
Reported-by: Niklas Cassel <cassel@kernel.org>
Closes: https://lore.kernel.org/linux-pci/aC9OrPAfpzB_A4K2@ryzen
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/pci/pci.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4d396bbab4a8..6d6e9ce2bbcc 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4985,10 +4985,19 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 	int ret;
 
-	if (host->reset_slot) {
+	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
+		/*
+		 * Save the config space of the root port before doing the
+		 * reset, since the state could be lost. The device state
+		 * should've been saved by the caller.
+		 */
+		pci_save_state(dev);
 		ret = host->reset_slot(host, dev);
 		if (ret)
 			pci_err(dev, "failed to reset slot: %d\n", ret);
+		else
+			/* Now restore it on success */
+			pci_restore_state(dev);
 
 		return;
 	}
-- 
2.43.0

[PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[Manivannan Sadhasivam]

The callback is supposed to reset the root port, hence it should be named
as 'reset_root_port'. This also warrants renaming the rest of the instances
of 'reset slot' as 'reset root port' in the drivers.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
---
 drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
 drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
 drivers/pci/controller/pci-host-common.c      | 20 +++++++++----------
 drivers/pci/pci.c                             |  6 +++---
 include/linux/pci.h                           |  2 +-
 5 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 193e97adf228..0cc7186758ce 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -85,7 +85,7 @@ struct rockchip_pcie_of_data {
 	const struct pci_epc_features *epc_features;
 };
 
-static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
+static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
 				       struct pci_dev *pdev);
 
 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip, u32 reg)
@@ -261,7 +261,7 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
 					 rockchip);
 
 	rockchip_pcie_enable_l0s(pci);
-	pp->bridge->reset_slot = rockchip_pcie_rc_reset_slot;
+	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;
 
 	return 0;
 }
@@ -700,7 +700,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
+static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
 				       struct pci_dev *pdev)
 {
 	struct pci_bus *bus = bridge->bus;
@@ -759,7 +759,7 @@ static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
 
 	/* Ignore errors, the link may come up later. */
 	dw_pcie_wait_for_link(pci);
-	dev_dbg(dev, "slot reset completed\n");
+	dev_dbg(dev, "Root port reset completed\n");
 	return ret;
 
 deinit_clk:
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 0c59030a2d55..840263c1efe0 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -291,7 +291,7 @@ struct qcom_pcie {
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
-static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
+static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
 				  struct pci_dev *pdev);
 
 static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
@@ -1277,7 +1277,7 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 			goto err_assert_reset;
 	}
 
-	pp->bridge->reset_slot = qcom_pcie_reset_slot;
+	pp->bridge->reset_root_port = qcom_pcie_reset_root_port;
 
 	return 0;
 
@@ -1533,7 +1533,7 @@ static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
 	}
 }
 
-static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
+static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
 				  struct pci_dev *pdev)
 {
 	struct pci_bus *bus = bridge->bus;
@@ -1589,7 +1589,7 @@ static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
 
 	qcom_pcie_start_link(pci);
 
-	dev_dbg(dev, "Slot reset completed\n");
+	dev_dbg(dev, "Root port reset completed\n");
 
 	return 0;
 
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index afa7b140a04a..24e357e85adb 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -99,22 +99,22 @@ void pci_host_common_remove(struct platform_device *pdev)
 EXPORT_SYMBOL_GPL(pci_host_common_remove);
 
 #if IS_ENABLED(CONFIG_PCIEAER)
-static pci_ers_result_t pci_host_reset_slot(struct pci_dev *dev)
+static pci_ers_result_t pci_host_reset_root_port(struct pci_dev *dev)
 {
 	int ret;
 
 	ret = pci_bus_error_reset(dev);
 	if (ret) {
-		pci_err(dev, "Failed to reset slot: %d\n", ret);
+		pci_err(dev, "Failed to reset root port: %d\n", ret);
 		return PCI_ERS_RESULT_DISCONNECT;
 	}
 
-	pci_info(dev, "Slot has been reset\n");
+	pci_info(dev, "Root port has been reset\n");
 
 	return PCI_ERS_RESULT_RECOVERED;
 }
 
-static void pci_host_recover_slots(struct pci_host_bridge *host)
+static void pci_host_reset_root_ports(struct pci_host_bridge *host)
 {
 	struct pci_bus *bus = host->bus;
 	struct pci_dev *dev;
@@ -124,11 +124,11 @@ static void pci_host_recover_slots(struct pci_host_bridge *host)
 			continue;
 
 		pcie_do_recovery(dev, pci_channel_io_frozen,
-				 pci_host_reset_slot);
+				 pci_host_reset_root_port);
 	}
 }
 #else
-static void pci_host_recover_slots(struct pci_host_bridge *host)
+static void pci_host_reset_root_ports(struct pci_host_bridge *host)
 {
 	struct pci_bus *bus = host->bus;
 	struct pci_dev *dev;
@@ -140,17 +140,17 @@ static void pci_host_recover_slots(struct pci_host_bridge *host)
 
 		ret = pci_bus_error_reset(dev);
 		if (ret)
-			pci_err(dev, "Failed to reset slot: %d\n", ret);
+			pci_err(dev, "Failed to reset root port: %d\n", ret);
 		else
-			pci_info(dev, "Slot has been reset\n");
+			pci_info(dev, "Root port has been reset\n");
 	}
 }
 #endif
 
 void pci_host_handle_link_down(struct pci_host_bridge *bridge)
 {
-	dev_info(&bridge->dev, "Recovering slots due to Link Down\n");
-	pci_host_recover_slots(bridge);
+	dev_info(&bridge->dev, "Recovering root ports due to Link Down\n");
+	pci_host_reset_root_ports(bridge);
 }
 EXPORT_SYMBOL_GPL(pci_host_handle_link_down);
 
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6d6e9ce2bbcc..154d33e1af84 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4985,16 +4985,16 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
 	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
 	int ret;
 
-	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
+	if (pci_is_root_bus(dev->bus) && host->reset_root_port) {
 		/*
 		 * Save the config space of the root port before doing the
 		 * reset, since the state could be lost. The device state
 		 * should've been saved by the caller.
 		 */
 		pci_save_state(dev);
-		ret = host->reset_slot(host, dev);
+		ret = host->reset_root_port(host, dev);
 		if (ret)
-			pci_err(dev, "failed to reset slot: %d\n", ret);
+			pci_err(dev, "failed to reset root port: %d\n", ret);
 		else
 			/* Now restore it on success */
 			pci_restore_state(dev);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8d7d2a49b76c..ab4f4a668f6d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -599,7 +599,7 @@ struct pci_host_bridge {
 	void (*release_fn)(struct pci_host_bridge *);
 	int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
 	void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
-	int (*reset_slot)(struct pci_host_bridge *bridge, struct pci_dev *dev);
+	int (*reset_root_port)(struct pci_host_bridge *bridge, struct pci_dev *dev);
 	void		*release_data;
 	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
 	unsigned int	no_ext_tags:1;		/* No Extended Tags */
-- 
2.43.0

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Niklas Cassel]

On Sun, May 25, 2025 at 12:23:03AM +0530, Manivannan Sadhasivam wrote:
> host_bridge::reset_slot() is supposed to reset the PCI root port/slot. Once
> that happens, the config space content would be lost. This was reported by
> Niklas on the dw-rockchip based platform where the MPS setting of the root
> port was lost after the host_bridge::reset_slot() callback. Hence, save the
> config space before calling the host_bridge::reset_slot() callback and
> restore it afterwards.
> 
> While at it, make sure that the callback is only called for root ports by
> checking if the bridge is behind the root bus.
> 
> Fixes: d5c1e1c25b37 ("PCI/ERR: Add support for resetting the slots in a platform specific way")
> Reported-by: Niklas Cassel <cassel@kernel.org>
> Closes: https://lore.kernel.org/linux-pci/aC9OrPAfpzB_A4K2@ryzen
> Suggested-by: Lukas Wunner <lukas@wunner.de>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/pci.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 4d396bbab4a8..6d6e9ce2bbcc 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4985,10 +4985,19 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>  	int ret;
>  
> -	if (host->reset_slot) {
> +	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
> +		/*
> +		 * Save the config space of the root port before doing the
> +		 * reset, since the state could be lost. The device state
> +		 * should've been saved by the caller.
> +		 */
> +		pci_save_state(dev);
>  		ret = host->reset_slot(host, dev);
>  		if (ret)
>  			pci_err(dev, "failed to reset slot: %d\n", ret);
> +		else
> +			/* Now restore it on success */
> +			pci_restore_state(dev);
>  
>  		return;
>  	}
> -- 
> 2.43.0
> 

Looks good to me:
Reviewed-by: Niklas Cassel <cassel@kernel.org>

Re: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[Niklas Cassel]

On Sun, May 25, 2025 at 12:23:04AM +0530, Manivannan Sadhasivam wrote:
> The callback is supposed to reset the root port, hence it should be named
> as 'reset_root_port'. This also warrants renaming the rest of the instances
> of 'reset slot' as 'reset root port' in the drivers.
> 
> Suggested-by: Lukas Wunner <lukas@wunner.de>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
>  drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
>  drivers/pci/controller/pci-host-common.c      | 20 +++++++++----------
>  drivers/pci/pci.c                             |  6 +++---
>  include/linux/pci.h                           |  2 +-
>  5 files changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index 193e97adf228..0cc7186758ce 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -85,7 +85,7 @@ struct rockchip_pcie_of_data {
>  	const struct pci_epc_features *epc_features;
>  };
>  
> -static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
> +static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
>  				       struct pci_dev *pdev);
>  
>  static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip, u32 reg)
> @@ -261,7 +261,7 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
>  					 rockchip);
>  
>  	rockchip_pcie_enable_l0s(pci);
> -	pp->bridge->reset_slot = rockchip_pcie_rc_reset_slot;
> +	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;

You just renamed the function to rockchip_pcie_rc_reset_root_port(),
but you seem to use the old name here, so I would guess that this will
not compile.

With the function pointer renamed, this patch looks good to me:
Reviewed-by: Niklas Cassel <cassel@kernel.org>


>  
>  	return 0;
>  }
> @@ -700,7 +700,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
>  	return ret;
>  }
>  
> -static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
> +static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
>  				       struct pci_dev *pdev)
>  {
>  	struct pci_bus *bus = bridge->bus;
> @@ -759,7 +759,7 @@ static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
>  
>  	/* Ignore errors, the link may come up later. */
>  	dw_pcie_wait_for_link(pci);
> -	dev_dbg(dev, "slot reset completed\n");
> +	dev_dbg(dev, "Root port reset completed\n");
>  	return ret;
>  
>  deinit_clk:
> diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
> index 0c59030a2d55..840263c1efe0 100644
> --- a/drivers/pci/controller/dwc/pcie-qcom.c
> +++ b/drivers/pci/controller/dwc/pcie-qcom.c
> @@ -291,7 +291,7 @@ struct qcom_pcie {
>  };
>  
>  #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
> -static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
> +static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
>  				  struct pci_dev *pdev);
>  
>  static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
> @@ -1277,7 +1277,7 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
>  			goto err_assert_reset;
>  	}
>  
> -	pp->bridge->reset_slot = qcom_pcie_reset_slot;
> +	pp->bridge->reset_root_port = qcom_pcie_reset_root_port;
>  
>  	return 0;
>  
> @@ -1533,7 +1533,7 @@ static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
>  	}
>  }
>  
> -static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
> +static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
>  				  struct pci_dev *pdev)
>  {
>  	struct pci_bus *bus = bridge->bus;
> @@ -1589,7 +1589,7 @@ static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
>  
>  	qcom_pcie_start_link(pci);
>  
> -	dev_dbg(dev, "Slot reset completed\n");
> +	dev_dbg(dev, "Root port reset completed\n");
>  
>  	return 0;
>  
> diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
> index afa7b140a04a..24e357e85adb 100644
> --- a/drivers/pci/controller/pci-host-common.c
> +++ b/drivers/pci/controller/pci-host-common.c
> @@ -99,22 +99,22 @@ void pci_host_common_remove(struct platform_device *pdev)
>  EXPORT_SYMBOL_GPL(pci_host_common_remove);
>  
>  #if IS_ENABLED(CONFIG_PCIEAER)
> -static pci_ers_result_t pci_host_reset_slot(struct pci_dev *dev)
> +static pci_ers_result_t pci_host_reset_root_port(struct pci_dev *dev)
>  {
>  	int ret;
>  
>  	ret = pci_bus_error_reset(dev);
>  	if (ret) {
> -		pci_err(dev, "Failed to reset slot: %d\n", ret);
> +		pci_err(dev, "Failed to reset root port: %d\n", ret);
>  		return PCI_ERS_RESULT_DISCONNECT;
>  	}
>  
> -	pci_info(dev, "Slot has been reset\n");
> +	pci_info(dev, "Root port has been reset\n");
>  
>  	return PCI_ERS_RESULT_RECOVERED;
>  }
>  
> -static void pci_host_recover_slots(struct pci_host_bridge *host)
> +static void pci_host_reset_root_ports(struct pci_host_bridge *host)
>  {
>  	struct pci_bus *bus = host->bus;
>  	struct pci_dev *dev;
> @@ -124,11 +124,11 @@ static void pci_host_recover_slots(struct pci_host_bridge *host)
>  			continue;
>  
>  		pcie_do_recovery(dev, pci_channel_io_frozen,
> -				 pci_host_reset_slot);
> +				 pci_host_reset_root_port);
>  	}
>  }
>  #else
> -static void pci_host_recover_slots(struct pci_host_bridge *host)
> +static void pci_host_reset_root_ports(struct pci_host_bridge *host)
>  {
>  	struct pci_bus *bus = host->bus;
>  	struct pci_dev *dev;
> @@ -140,17 +140,17 @@ static void pci_host_recover_slots(struct pci_host_bridge *host)
>  
>  		ret = pci_bus_error_reset(dev);
>  		if (ret)
> -			pci_err(dev, "Failed to reset slot: %d\n", ret);
> +			pci_err(dev, "Failed to reset root port: %d\n", ret);
>  		else
> -			pci_info(dev, "Slot has been reset\n");
> +			pci_info(dev, "Root port has been reset\n");
>  	}
>  }
>  #endif
>  
>  void pci_host_handle_link_down(struct pci_host_bridge *bridge)
>  {
> -	dev_info(&bridge->dev, "Recovering slots due to Link Down\n");
> -	pci_host_recover_slots(bridge);
> +	dev_info(&bridge->dev, "Recovering root ports due to Link Down\n");
> +	pci_host_reset_root_ports(bridge);
>  }
>  EXPORT_SYMBOL_GPL(pci_host_handle_link_down);
>  
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 6d6e9ce2bbcc..154d33e1af84 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4985,16 +4985,16 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>  	int ret;
>  
> -	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
> +	if (pci_is_root_bus(dev->bus) && host->reset_root_port) {
>  		/*
>  		 * Save the config space of the root port before doing the
>  		 * reset, since the state could be lost. The device state
>  		 * should've been saved by the caller.
>  		 */
>  		pci_save_state(dev);
> -		ret = host->reset_slot(host, dev);
> +		ret = host->reset_root_port(host, dev);
>  		if (ret)
> -			pci_err(dev, "failed to reset slot: %d\n", ret);
> +			pci_err(dev, "failed to reset root port: %d\n", ret);
>  		else
>  			/* Now restore it on success */
>  			pci_restore_state(dev);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 8d7d2a49b76c..ab4f4a668f6d 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -599,7 +599,7 @@ struct pci_host_bridge {
>  	void (*release_fn)(struct pci_host_bridge *);
>  	int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
>  	void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
> -	int (*reset_slot)(struct pci_host_bridge *bridge, struct pci_dev *dev);
> +	int (*reset_root_port)(struct pci_host_bridge *bridge, struct pci_dev *dev);
>  	void		*release_data;
>  	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
>  	unsigned int	no_ext_tags:1;		/* No Extended Tags */
> -- 
> 2.43.0
> 

Re: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[kernel test robot]

Hi Manivannan,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on next-20250523]
[cannot apply to pci/for-linus linus/master v6.15-rc7]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Manivannan-Sadhasivam/PCI-Save-and-restore-root-port-config-space-in-pcibios_reset_secondary_bus/20250525-025535
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250524185304.26698-3-manivannan.sadhasivam%40linaro.org
patch subject: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()
config: csky-randconfig-002-20250525 (https://download.01.org/0day-ci/archive/20250525/202505250525.2csmeURe-lkp@intel.com/config)
compiler: csky-linux-gcc (GCC) 10.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250525/202505250525.2csmeURe-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/202505250525.2csmeURe-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   drivers/pci/controller/dwc/pcie-dw-rockchip.c: In function 'rockchip_pcie_host_init':
>> drivers/pci/controller/dwc/pcie-dw-rockchip.c:264:32: error: 'rockchip_pcie_rc_reset_slot' undeclared (first use in this function); did you mean 'rockchip_pcie_rc_reset_root_port'?
     264 |  pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;
         |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                                rockchip_pcie_rc_reset_root_port
   drivers/pci/controller/dwc/pcie-dw-rockchip.c:264:32: note: each undeclared identifier is reported only once for each function it appears in
   At top level:
>> drivers/pci/controller/dwc/pcie-dw-rockchip.c:703:12: warning: 'rockchip_pcie_rc_reset_root_port' defined but not used [-Wunused-function]
     703 | static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
         |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +264 drivers/pci/controller/dwc/pcie-dw-rockchip.c

   244	
   245	static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
   246	{
   247		struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
   248		struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
   249		struct device *dev = rockchip->pci.dev;
   250		int irq, ret;
   251	
   252		irq = of_irq_get_byname(dev->of_node, "legacy");
   253		if (irq < 0)
   254			return irq;
   255	
   256		ret = rockchip_pcie_init_irq_domain(rockchip);
   257		if (ret < 0)
   258			dev_err(dev, "failed to init irq domain\n");
   259	
   260		irq_set_chained_handler_and_data(irq, rockchip_pcie_intx_handler,
   261						 rockchip);
   262	
   263		rockchip_pcie_enable_l0s(pci);
 > 264		pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;
   265	
   266		return 0;
   267	}
   268	

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

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Wilfred Mallawa]

On Sun, 2025-05-25 at 00:23 +0530, Manivannan Sadhasivam wrote:
> host_bridge::reset_slot() is supposed to reset the PCI root
> port/slot. Once
> that happens, the config space content would be lost. This was
> reported by
> Niklas on the dw-rockchip based platform where the MPS setting of the
> root
> port was lost after the host_bridge::reset_slot() callback. Hence,
> save the
> config space before calling the host_bridge::reset_slot() callback
> and
> restore it afterwards.
> 
> While at it, make sure that the callback is only called for root
> ports by
> checking if the bridge is behind the root bus.
> 
> Fixes: d5c1e1c25b37 ("PCI/ERR: Add support for resetting the slots in
> a platform specific way")
> Reported-by: Niklas Cassel <cassel@kernel.org>
> Closes: https://lore.kernel.org/linux-pci/aC9OrPAfpzB_A4K2@ryzen
> Suggested-by: Lukas Wunner <lukas@wunner.de>
> Signed-off-by: Manivannan Sadhasivam
> <manivannan.sadhasivam@linaro.org>
> ---
>  drivers/pci/pci.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 4d396bbab4a8..6d6e9ce2bbcc 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4985,10 +4985,19 @@ void __weak
> pcibios_reset_secondary_bus(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev-
> >bus);
>  	int ret;
>  
> -	if (host->reset_slot) {
> +	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
> +		/*
> +		 * Save the config space of the root port before
> doing the
> +		 * reset, since the state could be lost. The device
> state
> +		 * should've been saved by the caller.
> +		 */
> +		pci_save_state(dev);
>  		ret = host->reset_slot(host, dev);
>  		if (ret)
>  			pci_err(dev, "failed to reset slot: %d\n",
> ret);
> +		else
> +			/* Now restore it on success */
> +			pci_restore_state(dev);
>  
>  		return;
>  	}
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>

Re: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[Wilfred Mallawa]

On Sat, 2025-05-24 at 22:57 +0200, Niklas Cassel wrote:
> On Sun, May 25, 2025 at 12:23:04AM +0530, Manivannan Sadhasivam
> wrote:
> > The callback is supposed to reset the root port, hence it should be
> > named
> > as 'reset_root_port'. This also warrants renaming the rest of the
> > instances
> > of 'reset slot' as 'reset root port' in the drivers.
> > 
> > Suggested-by: Lukas Wunner <lukas@wunner.de>
> > Signed-off-by: Manivannan Sadhasivam
> > <manivannan.sadhasivam@linaro.org>
> > ---
> >  drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
> >  drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
> >  drivers/pci/controller/pci-host-common.c      | 20 +++++++++------
> > ----
> >  drivers/pci/pci.c                             |  6 +++---
> >  include/linux/pci.h                           |  2 +-
> >  5 files changed, 22 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > index 193e97adf228..0cc7186758ce 100644
> > --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > @@ -85,7 +85,7 @@ struct rockchip_pcie_of_data {
> >  	const struct pci_epc_features *epc_features;
> >  };
> >  
> > -static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge
> > *bridge,
> > +static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge
> > *bridge,
> >  				       struct pci_dev *pdev);
> >  
> >  static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip,
> > u32 reg)
> > @@ -261,7 +261,7 @@ static int rockchip_pcie_host_init(struct
> > dw_pcie_rp *pp)
> >  					 rockchip);
> >  
> >  	rockchip_pcie_enable_l0s(pci);
> > -	pp->bridge->reset_slot = rockchip_pcie_rc_reset_slot;
> > +	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;
> 
> You just renamed the function to rockchip_pcie_rc_reset_root_port(),
> but you seem to use the old name here, so I would guess that this
> will
> not compile.
> 
> With the function pointer renamed, this patch looks good to me:
> Reviewed-by: Niklas Cassel <cassel@kernel.org>
> 
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>

> 

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Lukas Wunner]

On Sun, May 25, 2025 at 12:23:03AM +0530, Manivannan Sadhasivam wrote:
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4985,10 +4985,19 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
>  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
>  	int ret;
>  
> -	if (host->reset_slot) {
> +	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
> +		/*
> +		 * Save the config space of the root port before doing the
> +		 * reset, since the state could be lost. The device state
> +		 * should've been saved by the caller.
> +		 */
> +		pci_save_state(dev);
>  		ret = host->reset_slot(host, dev);

Nit:  Capitalize terms as the PCIe Base Spec does, i.e. "Root Port".

"The device state" is ambiguous as the Root Port is a device itself
and even referred to by the "dev" variable.  I think what you mean
is "The Endpoint state".

Thanks,

Lukas

Re: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[Lukas Wunner]

Eight more occurrences where "Root Port" should be capitalized:

On Sun, May 25, 2025 at 12:23:04AM +0530, Manivannan Sadhasivam wrote:
> @@ -759,7 +759,7 @@ static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
>  
>  	/* Ignore errors, the link may come up later. */
>  	dw_pcie_wait_for_link(pci);
> -	dev_dbg(dev, "slot reset completed\n");
> +	dev_dbg(dev, "Root port reset completed\n");
>  	return ret;
>  
>  deinit_clk:

> @@ -1589,7 +1589,7 @@ static int qcom_pcie_reset_slot(struct pci_host_bridge *bridge,
>  
>  	qcom_pcie_start_link(pci);
>  
> -	dev_dbg(dev, "Slot reset completed\n");
> +	dev_dbg(dev, "Root port reset completed\n");
>  
>  	return 0;
>  

> @@ -99,22 +99,22 @@ void pci_host_common_remove(struct platform_device *pdev)
>  	ret = pci_bus_error_reset(dev);
>  	if (ret) {
> -		pci_err(dev, "Failed to reset slot: %d\n", ret);
> +		pci_err(dev, "Failed to reset root port: %d\n", ret);
>  		return PCI_ERS_RESULT_DISCONNECT;
>  	}
>  
> -	pci_info(dev, "Slot has been reset\n");
> +	pci_info(dev, "Root port has been reset\n");
>  
>  	return PCI_ERS_RESULT_RECOVERED;
>  }

> @@ -140,17 +140,17 @@ static void pci_host_recover_slots(struct pci_host_bridge *host)
>  
>  		ret = pci_bus_error_reset(dev);
>  		if (ret)
> -			pci_err(dev, "Failed to reset slot: %d\n", ret);
> +			pci_err(dev, "Failed to reset root port: %d\n", ret);
>  		else
> -			pci_info(dev, "Slot has been reset\n");
> +			pci_info(dev, "Root port has been reset\n");
>  	}
>  }
>  #endif
>  
>  void pci_host_handle_link_down(struct pci_host_bridge *bridge)
>  {
> -	dev_info(&bridge->dev, "Recovering slots due to Link Down\n");
> -	pci_host_recover_slots(bridge);
> +	dev_info(&bridge->dev, "Recovering root ports due to Link Down\n");
> +	pci_host_reset_root_ports(bridge);
>  }
>  EXPORT_SYMBOL_GPL(pci_host_handle_link_down);
>  
> @@ -4985,16 +4985,16 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
> +		ret = host->reset_root_port(host, dev);
>  		if (ret)
> -			pci_err(dev, "failed to reset slot: %d\n", ret);
> +			pci_err(dev, "failed to reset root port: %d\n", ret);
>  		else
>  			/* Now restore it on success */
>  			pci_restore_state(dev);

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Manivannan Sadhasivam]

On Sun, May 25, 2025 at 09:22:03AM +0200, Lukas Wunner wrote:
> On Sun, May 25, 2025 at 12:23:03AM +0530, Manivannan Sadhasivam wrote:
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -4985,10 +4985,19 @@ void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
> >  	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> >  	int ret;
> >  
> > -	if (host->reset_slot) {
> > +	if (pci_is_root_bus(dev->bus) && host->reset_slot) {
> > +		/*
> > +		 * Save the config space of the root port before doing the
> > +		 * reset, since the state could be lost. The device state
> > +		 * should've been saved by the caller.
> > +		 */
> > +		pci_save_state(dev);
> >  		ret = host->reset_slot(host, dev);
> 
> Nit:  Capitalize terms as the PCIe Base Spec does, i.e. "Root Port".
> 

Ack.

> "The device state" is ambiguous as the Root Port is a device itself
> and even referred to by the "dev" variable.  I think what you mean
> is "The Endpoint state".
> 

Yes! Will fix them while applying, thanks!

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH 2/2] PCI: Rename host_bridge::reset_slot() to host_bridge::reset_root_port()

[Manivannan Sadhasivam]

On Sat, May 24, 2025 at 10:57:44PM +0200, Niklas Cassel wrote:
> On Sun, May 25, 2025 at 12:23:04AM +0530, Manivannan Sadhasivam wrote:
> > The callback is supposed to reset the root port, hence it should be named
> > as 'reset_root_port'. This also warrants renaming the rest of the instances
> > of 'reset slot' as 'reset root port' in the drivers.
> > 
> > Suggested-by: Lukas Wunner <lukas@wunner.de>
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> >  drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
> >  drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
> >  drivers/pci/controller/pci-host-common.c      | 20 +++++++++----------
> >  drivers/pci/pci.c                             |  6 +++---
> >  include/linux/pci.h                           |  2 +-
> >  5 files changed, 22 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > index 193e97adf228..0cc7186758ce 100644
> > --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> > @@ -85,7 +85,7 @@ struct rockchip_pcie_of_data {
> >  	const struct pci_epc_features *epc_features;
> >  };
> >  
> > -static int rockchip_pcie_rc_reset_slot(struct pci_host_bridge *bridge,
> > +static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
> >  				       struct pci_dev *pdev);
> >  
> >  static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip, u32 reg)
> > @@ -261,7 +261,7 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
> >  					 rockchip);
> >  
> >  	rockchip_pcie_enable_l0s(pci);
> > -	pp->bridge->reset_slot = rockchip_pcie_rc_reset_slot;
> > +	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_slot;
> 
> You just renamed the function to rockchip_pcie_rc_reset_root_port(),
> but you seem to use the old name here, so I would guess that this will
> not compile.
> 

Yeah, I guess I exposed my sed skills here :P Will fix it up while applying.

> With the function pointer renamed, this patch looks good to me:
> Reviewed-by: Niklas Cassel <cassel@kernel.org>
> 

Thanks!

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH 0/2] PCI: Slot reset fixes

[Wilfred Mallawa]

On Sun, 2025-05-25 at 00:23 +0530, Manivannan Sadhasivam wrote:
> Hi,
> 
> This series fixes the issues reported for the slot reset feature
> merged for
> v6.16.
> 
> This series is on top of dw-rockchip branch where the slot reset
> patches are
> merged. The patches in this series can be squashed into the
> respective commits
> since they are not merged into mainline.
> 
> - Mani
> 
> Manivannan Sadhasivam (2):
>   PCI: Save and restore root port config space in
>     pcibios_reset_secondary_bus()
>   PCI: Rename host_bridge::reset_slot() to
>     host_bridge::reset_root_port()
> 
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
>  drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
>  drivers/pci/controller/pci-host-common.c      | 20 +++++++++--------
> --
>  drivers/pci/pci.c                             | 15 +++++++++++---
>  include/linux/pci.h                           |  2 +-
>  5 files changed, 31 insertions(+), 22 deletions(-)
Hey Mani,

I tested this series with the Rock5B RC <-> Rock5B EP. As expected, bus
resets now work as intended. Feel free to use:

Tested-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>

Cheers,
Wilfred

Re: [PATCH 0/2] PCI: Slot reset fixes

[Manivannan Sadhasivam]

On Sun, May 25, 2025 at 12:23:02AM +0530, Manivannan Sadhasivam wrote:
> Hi,
> 
> This series fixes the issues reported for the slot reset feature merged for
> v6.16.
> 
> This series is on top of dw-rockchip branch where the slot reset patches are
> merged. The patches in this series can be squashed into the respective commits
> since they are not merged into mainline.
> 

Squashed to dw-rockchip!

- Mani

> - Mani
> 
> Manivannan Sadhasivam (2):
>   PCI: Save and restore root port config space in
>     pcibios_reset_secondary_bus()
>   PCI: Rename host_bridge::reset_slot() to
>     host_bridge::reset_root_port()
> 
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c |  8 ++++----
>  drivers/pci/controller/dwc/pcie-qcom.c        |  8 ++++----
>  drivers/pci/controller/pci-host-common.c      | 20 +++++++++----------
>  drivers/pci/pci.c                             | 15 +++++++++++---
>  include/linux/pci.h                           |  2 +-
>  5 files changed, 31 insertions(+), 22 deletions(-)
> 
> -- 
> 2.43.0
> 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Lukas Wunner]

On Sun, May 25, 2025 at 01:28:18PM +0530, Manivannan Sadhasivam wrote:
> On Sun, May 25, 2025 at 09:22:03AM +0200, Lukas Wunner wrote:
> > "The device state" is ambiguous as the Root Port is a device itself
> > and even referred to by the "dev" variable.  I think what you mean
> > is "The Endpoint state".
> > 
> 
> Yes! Will fix them while applying, thanks!

ICYMI, current controller/dw-rockchip branch still uses
"The device state", not "The Endpoint state" in commit
56eecfc8f46f ("PCI/ERR: Add support for resetting the
Root Ports in a platform specific way").

Otherwise LGTM.

Thanks,

Lukas

Re: [PATCH 1/2] PCI: Save and restore root port config space in pcibios_reset_secondary_bus()

[Manivannan Sadhasivam]

On Mon, May 26, 2025 at 08:54:37AM +0200, Lukas Wunner wrote:
> On Sun, May 25, 2025 at 01:28:18PM +0530, Manivannan Sadhasivam wrote:
> > On Sun, May 25, 2025 at 09:22:03AM +0200, Lukas Wunner wrote:
> > > "The device state" is ambiguous as the Root Port is a device itself
> > > and even referred to by the "dev" variable.  I think what you mean
> > > is "The Endpoint state".
> > > 
> > 
> > Yes! Will fix them while applying, thanks!
> 
> ICYMI, current controller/dw-rockchip branch still uses
> "The device state", not "The Endpoint state" in commit
> 56eecfc8f46f ("PCI/ERR: Add support for resetting the
> Root Ports in a platform specific way").
> 

Ah, missed this comment. Incorported now!

- Mani

-- 
மணிவண்ணன் சதாசிவம்