Re: [PATCH v10 08/17] cxl/pci: Move RAS initialization to cxl_port driver

[Dave Jiang <dave.jiang@intel.com>]

On 6/26/25 3:42 PM, Terry Bowman wrote:
> The cxl_port driver is intended to manage CXL Endpoint Ports and CXL Switch
> Ports. Move existing RAS initialization to the cxl_port driver.
> 
> Restricted CXL Host (RCH) Downstream Port RAS initialization currently
> resides in cxl/core/pci.c. The PCI source file is not otherwise associated
> with CXL Port management.
> 
> Additional CXL Port RAS initialization will be added in future patches to
> support a CXL Port device's CXL errors.
> 
> Signed-off-by: Terry Bowman <terry.bowman@amd.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/cxl/core/pci.c  | 73 --------------------------------------
>  drivers/cxl/core/regs.c |  2 ++
>  drivers/cxl/cxl.h       |  6 ++++
>  drivers/cxl/port.c      | 78 +++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 86 insertions(+), 73 deletions(-)
> 
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> index 06464a25d8bd..35c9c50534bf 100644
> --- a/drivers/cxl/core/pci.c
> +++ b/drivers/cxl/core/pci.c
> @@ -738,79 +738,6 @@ static bool cxl_handle_ras(struct cxl_dev_state *cxlds,
>  
>  #ifdef CONFIG_PCIEAER_CXL
>  
> -static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
> -{
> -	resource_size_t aer_phys;
> -	struct device *host;
> -	u16 aer_cap;
> -
> -	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
> -	if (aer_cap) {
> -		host = dport->reg_map.host;
> -		aer_phys = aer_cap + dport->rcrb.base;
> -		dport->regs.dport_aer = devm_cxl_iomap_block(host, aer_phys,
> -						sizeof(struct aer_capability_regs));
> -	}
> -}
> -
> -static void cxl_dport_map_ras(struct cxl_dport *dport)
> -{
> -	struct cxl_register_map *map = &dport->reg_map;
> -	struct device *dev = dport->dport_dev;
> -
> -	if (!map->component_map.ras.valid)
> -		dev_dbg(dev, "RAS registers not found\n");
> -	else if (cxl_map_component_regs(map, &dport->regs.component,
> -					BIT(CXL_CM_CAP_CAP_ID_RAS)))
> -		dev_dbg(dev, "Failed to map RAS capability.\n");
> -}
> -
> -static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
> -{
> -	void __iomem *aer_base = dport->regs.dport_aer;
> -	u32 aer_cmd_mask, aer_cmd;
> -
> -	if (!aer_base)
> -		return;
> -
> -	/*
> -	 * Disable RCH root port command interrupts.
> -	 * CXL 3.0 12.2.1.1 - RCH Downstream Port-detected Errors
> -	 *
> -	 * This sequence may not be necessary. CXL spec states disabling
> -	 * the root cmd register's interrupts is required. But, PCI spec
> -	 * shows these are disabled by default on reset.
> -	 */
> -	aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN |
> -			PCI_ERR_ROOT_CMD_NONFATAL_EN |
> -			PCI_ERR_ROOT_CMD_FATAL_EN);
> -	aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND);
> -	aer_cmd &= ~aer_cmd_mask;
> -	writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
> -}
> -
> -/**
> - * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
> - * @dport: the cxl_dport that needs to be initialized
> - * @host: host device for devm operations
> - */
> -void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
> -{
> -	dport->reg_map.host = host;
> -	cxl_dport_map_ras(dport);
> -
> -	if (dport->rch) {
> -		struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport->dport_dev);
> -
> -		if (!host_bridge->native_aer)
> -			return;
> -
> -		cxl_dport_map_rch_aer(dport);
> -		cxl_disable_rch_root_ints(dport);
> -	}
> -}
> -EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
> -
>  static void cxl_handle_rdport_cor_ras(struct cxl_dev_state *cxlds,
>  					  struct cxl_dport *dport)
>  {
> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index 5ca7b0eed568..b8e767a9571c 100644
> --- a/drivers/cxl/core/regs.c
> +++ b/drivers/cxl/core/regs.c
> @@ -199,6 +199,7 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
>  
>  	return ret_val;
>  }
> +EXPORT_SYMBOL_NS_GPL(devm_cxl_iomap_block, "CXL");
>  
>  int cxl_map_component_regs(const struct cxl_register_map *map,
>  			   struct cxl_component_regs *regs,
> @@ -517,6 +518,7 @@ u16 cxl_rcrb_to_aer(struct device *dev, resource_size_t rcrb)
>  
>  	return offset;
>  }
> +EXPORT_SYMBOL_NS_GPL(cxl_rcrb_to_aer, "CXL");
>  
>  static resource_size_t cxl_rcrb_to_linkcap(struct device *dev, struct cxl_dport *dport)
>  {
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 3f1695c96abc..c57c160f3e5e 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -313,6 +313,12 @@ int cxl_setup_regs(struct cxl_register_map *map);
>  struct cxl_dport;
>  resource_size_t cxl_rcd_component_reg_phys(struct device *dev,
>  					   struct cxl_dport *dport);
> +
> +u16 cxl_rcrb_to_aer(struct device *dev, resource_size_t rcrb);
> +
> +void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr,
> +				   resource_size_t length);
> +
>  int cxl_dport_map_rcd_linkcap(struct pci_dev *pdev, struct cxl_dport *dport);
>  
>  #define CXL_RESOURCE_NONE ((resource_size_t) -1)
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index fe4b593331da..021f35145c65 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -6,6 +6,7 @@
>  
>  #include "cxlmem.h"
>  #include "cxlpci.h"
> +#include "cxl.h"
>  
>  /**
>   * DOC: cxl port
> @@ -57,6 +58,83 @@ static int discover_region(struct device *dev, void *unused)
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PCIEAER_CXL
> +
> +static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
> +{
> +	resource_size_t aer_phys;
> +	struct device *host;
> +	u16 aer_cap;
> +
> +	aer_cap = cxl_rcrb_to_aer(dport->dport_dev, dport->rcrb.base);
> +	if (aer_cap) {
> +		host = dport->reg_map.host;
> +		aer_phys = aer_cap + dport->rcrb.base;
> +		dport->regs.dport_aer = devm_cxl_iomap_block(host, aer_phys,
> +						sizeof(struct aer_capability_regs));
> +	}
> +}
> +
> +static void cxl_dport_map_ras(struct cxl_dport *dport)
> +{
> +	struct cxl_register_map *map = &dport->reg_map;
> +	struct device *dev = dport->dport_dev;
> +
> +	if (!map->component_map.ras.valid)
> +		dev_dbg(dev, "RAS registers not found\n");
> +	else if (cxl_map_component_regs(map, &dport->regs.component,
> +					BIT(CXL_CM_CAP_CAP_ID_RAS)))
> +		dev_dbg(dev, "Failed to map RAS capability.\n");
> +}
> +
> +static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
> +{
> +	void __iomem *aer_base = dport->regs.dport_aer;
> +	u32 aer_cmd_mask, aer_cmd;
> +
> +	if (!aer_base)
> +		return;
> +
> +	/*
> +	 * Disable RCH root port command interrupts.
> +	 * CXL 3.2 12.2.1.1 - RCH Downstream Port-detected Errors
> +	 *
> +	 * This sequence may not be necessary. CXL spec states disabling
> +	 * the root cmd register's interrupts is required. But, PCI spec
> +	 * shows these are disabled by default on reset.
> +	 */
> +	aer_cmd_mask = (PCI_ERR_ROOT_CMD_COR_EN |
> +			PCI_ERR_ROOT_CMD_NONFATAL_EN |
> +			PCI_ERR_ROOT_CMD_FATAL_EN);
> +	aer_cmd = readl(aer_base + PCI_ERR_ROOT_COMMAND);
> +	aer_cmd &= ~aer_cmd_mask;
> +	writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
> +}
> +
> +/**
> + * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
> + * @dport: the cxl_dport that needs to be initialized
> + * @host: host device for devm operations
> + */
> +void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
> +{
> +	dport->reg_map.host = host;
> +	cxl_dport_map_ras(dport);
> +
> +	if (dport->rch) {
> +		struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport->dport_dev);
> +
> +		if (!host_bridge->native_aer)
> +			return;
> +
> +		cxl_dport_map_rch_aer(dport);
> +		cxl_disable_rch_root_ints(dport);
> +	}
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
> +
> +#endif /* CONFIG_PCIEAER_CXL */
> +
>  static int cxl_switch_port_probe(struct cxl_port *port)
>  {
>  	struct cxl_hdm *cxlhdm;