From: Manivannan Sadhasivam <mani@kernel.org>

Some host bridge devices require resetting the Root Ports in a platform
specific way to recover them from error conditions such as Fatal AER
errors, Link Down etc... So introduce pci_host_bridge::reset_root_port()
callback and call it from pcibios_reset_secondary_bus() if available. Also,
save the Root Port config space before reset and restore it afterwards.

The 'reset_root_port' callback is responsible for resetting the given Root
Port referenced by the 'pci_dev' pointer in a platform specific way and
bring it back to the working state if possible. If any error occurs during
the reset operation, relevant errno should be returned.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Tested-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/pci.c      | 20 ++++++++++++++++++++
 drivers/pci/pcie/err.c |  5 -----
 include/linux/pci.h    |  1 +
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8479c2e1f74f..6f09057d83e0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4812,6 +4812,26 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
 
 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_root_port) {
+		/*
+		 * Save the config space of the Root Port before doing the
+		 * reset, since the state could be lost. The Endpoint state
+		 * should've been saved by the caller.
+		 */
+		pci_save_state(dev);
+		ret = host->reset_root_port(host, dev);
+		if (ret)
+			pci_err(dev, "Failed to reset Root Port: %d\n", ret);
+		else
+			/* Now restore it on success */
+			pci_restore_state(dev);
+
+		return;
+	}
+
 	pci_reset_secondary_bus(dev);
 }
 
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index bebe4bc111d7..13b9d9eb714f 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -256,11 +256,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	}
 
 	if (status == PCI_ERS_RESULT_NEED_RESET) {
-		/*
-		 * TODO: Should call platform-specific
-		 * functions to reset slot before calling
-		 * drivers' slot_reset callbacks?
-		 */
 		status = PCI_ERS_RESULT_RECOVERED;
 		pci_dbg(bridge, "broadcast slot_reset message\n");
 		pci_walk_bridge(bridge, report_slot_reset, &status);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 1c270f1d5123..34c434b79abb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -644,6 +644,7 @@ 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_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 */

-- 
2.51.0

在 2026/03/10 星期二 22:01, Manivannan Sadhasivam via B4 Relay 写道:
> From: Manivannan Sadhasivam <mani@kernel.org>
> 
> Some host bridge devices require resetting the Root Ports in a platform
> specific way to recover them from error conditions such as Fatal AER
> errors, Link Down etc... So introduce pci_host_bridge::reset_root_port()
> callback and call it from pcibios_reset_secondary_bus() if available. Also,
> save the Root Port config space before reset and restore it afterwards.
> 
> The 'reset_root_port' callback is responsible for resetting the given Root
> Port referenced by the 'pci_dev' pointer in a platform specific way and
> bring it back to the working state if possible. If any error occurs during
> the reset operation, relevant errno should be returned.
> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> Tested-by: Brian Norris <briannorris@chromium.org>
> Tested-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
> Tested-by: Richard Zhu <hongxing.zhu@nxp.com>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
>   drivers/pci/pci.c      | 20 ++++++++++++++++++++
>   drivers/pci/pcie/err.c |  5 -----
>   include/linux/pci.h    |  1 +
>   3 files changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 8479c2e1f74f..6f09057d83e0 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4812,6 +4812,26 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
>   
>   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_root_port) {
> +		/*
> +		 * Save the config space of the Root Port before doing the
> +		 * reset, since the state could be lost. The Endpoint state
> +		 * should've been saved by the caller.
> +		 */
> +		pci_save_state(dev);
> +		ret = host->reset_root_port(host, dev);
> +		if (ret)
> +			pci_err(dev, "Failed to reset Root Port: %d\n", ret);
> +		else
> +			/* Now restore it on success */
> +			pci_restore_state(dev);
> +
> +		return;
> +	}
> +
>   	pci_reset_secondary_bus(dev);
>   }
>   

LGTM,

Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>

> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index bebe4bc111d7..13b9d9eb714f 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -256,11 +256,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
>   	}
>   
>   	if (status == PCI_ERS_RESULT_NEED_RESET) {
> -		/*
> -		 * TODO: Should call platform-specific
> -		 * functions to reset slot before calling
> -		 * drivers' slot_reset callbacks?
> -		 */
>   		status = PCI_ERS_RESULT_RECOVERED;
>   		pci_dbg(bridge, "broadcast slot_reset message\n");
>   		pci_walk_bridge(bridge, report_slot_reset, &status);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 1c270f1d5123..34c434b79abb 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -644,6 +644,7 @@ 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_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 */
>