Re: [PATCH v7 15/17] cxl/pci: Add support to assign and clear pci_driver::cxl_err_handlers

Dave Jiang
2025-02-12T00:38:47Z

On 2/11/25 12:24 PM, Terry Bowman wrote:
> pci_driver::cxl_err_handlers are not currently assigned handler callbacks.
> The handlers can't be set in the pci_driver static definition because the
> CXL PCIe Port devices are bound to the portdrv driver which is not CXL
> driver aware.
>
> Add cxl_assign_port_error_handlers() in the cxl_core module. This
> function will assign the default handlers for a CXL PCIe Port device.
>
> When the CXL Port (cxl_port or cxl_dport) is destroyed the device's
> pci_driver::cxl_err_handlers must be set to NULL indicating they should no
> longer be used.
>
> Create cxl_clear_port_error_handlers() and register it to be called
> when the CXL Port device (cxl_port or cxl_dport) is destroyed.
>
> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
> Reviewed-by: Gregory Price <gourry@gourry.net>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
> drivers/cxl/core/pci.c | 59 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 57 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> index f154dcf6dfda..03ae21a944e0 100644
> --- a/drivers/cxl/core/pci.c
> +++ b/drivers/cxl/core/pci.c
> @@ -860,8 +860,39 @@ static pci_ers_result_t cxl_port_error_detected(struct pci_dev *pdev)
> return __cxl_handle_ras(dev, &pdev->dev, ras_base);
> }
>
> +static const struct cxl_error_handlers cxl_port_error_handlers = {
> + .error_detected = cxl_port_error_detected,
> + .cor_error_detected = cxl_port_cor_error_detected,
> +};
> +
> +static void cxl_assign_port_error_handlers(struct pci_dev *pdev)
> +{
> + struct pci_driver *pdrv;
> +
> + if (!pdev || !pdev->driver || !get_device(&pdev->dev))
> + return;
> +
> + pdrv = pdev->driver;
> + pdrv->cxl_err_handler = &cxl_port_error_handlers;
> + put_device(&pdev->dev);
> +}
> +
> +static void cxl_clear_port_error_handlers(void *data)
> +{
> + struct pci_dev *pdev = data;
> + struct pci_driver *pdrv;
> +
> + if (!pdev || !pdev->driver || !get_device(&pdev->dev))
> + return;
> +
> + pdrv = pdev->driver;
> + pdrv->cxl_err_handler = NULL;
> + put_device(&pdev->dev);
> +}
> +
> void cxl_uport_init_ras_reporting(struct cxl_port *port)
> {
> + struct pci_dev *pdev = to_pci_dev(port->uport_dev);
>
> /* uport may have more than 1 downstream EP. Check if already mapped. */
> mutex_lock(&ras_init_mutex);
> @@ -872,9 +903,15 @@ void cxl_uport_init_ras_reporting(struct cxl_port *port)
>
> port->reg_map.host = &port->dev;
> if (cxl_map_component_regs(&port->reg_map, &port->uport_regs,
> - BIT(CXL_CM_CAP_CAP_ID_RAS)))
> + BIT(CXL_CM_CAP_CAP_ID_RAS))) {
> dev_err(&port->dev, "Failed to map RAS capability\n");
> + mutex_unlock(&ras_init_mutex);
> + return;
> + }
> mutex_unlock(&ras_init_mutex);
> +
> + cxl_assign_port_error_handlers(pdev);
> + devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
> }
> EXPORT_SYMBOL_NS_GPL(cxl_uport_init_ras_reporting, "CXL");
>
> @@ -886,6 +923,8 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
> {
> struct device *dport_dev = dport->dport_dev;
> struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport_dev);
> + struct pci_dev *pdev = to_pci_dev(dport_dev);
> + struct cxl_port *port;
>
> dport->reg_map.host = dport_dev;
> if (dport->rch && host_bridge->native_aer) {
> @@ -901,9 +940,25 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
> }
>
> if (cxl_map_component_regs(&dport->reg_map, &dport->regs.component,
> - BIT(CXL_CM_CAP_CAP_ID_RAS)))
> + BIT(CXL_CM_CAP_CAP_ID_RAS))) {
> dev_err(dport_dev, "Failed to map RAS capability\n");
> + mutex_unlock(&ras_init_mutex);
> + return;
> + }
> mutex_unlock(&ras_init_mutex);
> +
> + if (dport->rch)
> + return;
> +
> + port = find_cxl_port(dport_dev, NULL);
> + if (!port) {
> + dev_err(dport_dev, "Failed to find upstream port\n");
> + return;
> + }
> +
> + cxl_assign_port_error_handlers(pdev);
> + devm_add_action_or_reset(&port->dev, cxl_clear_port_error_handlers, pdev);
> + put_device(&port->dev);
> }
> EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
>