linux-kernel - [PATCH v5 15/16] cxl/pci: Add support to assign and clear pci_driver::cxl_err

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Message-ID: <20250107143852.3692571-16-terry.bowman@amd.com>
Date: Tue, 7 Jan 2025 08:38:51 -0600
From: Terry Bowman <terry.bowman@....com>
To: <linux-cxl@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-pci@...r.kernel.org>, <nifan.cxl@...il.com>, <dave@...olabs.net>,
	<jonathan.cameron@...wei.com>, <dave.jiang@...el.com>,
	<alison.schofield@...el.com>, <vishal.l.verma@...el.com>,
	<dan.j.williams@...el.com>, <bhelgaas@...gle.com>, <mahesh@...ux.ibm.com>,
	<ira.weiny@...el.com>, <oohall@...il.com>, <Benjamin.Cheatham@....com>,
	<rrichter@....com>, <nathan.fontenot@....com>, <terry.bowman@....com>,
	<Smita.KoralahalliChannabasappa@....com>, <lukas@...ner.de>,
	<ming.li@...omail.com>, <PradeepVineshReddy.Kodamati@....com>,
	<alucerop@....com>
Subject: [PATCH v5 15/16] cxl/pci: Add support to assign and clear pci_driver::cxl_err_handlers

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@....com>
---
 drivers/cxl/core/pci.c | 49 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 3e87fe54a1a2..9c162120f0fe 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -848,8 +848,40 @@ static bool cxl_port_error_detected(struct pci_dev *pdev)
 	return __cxl_handle_ras(&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. */
 	if (port->uport_regs.ras)
 		return;
@@ -860,6 +892,9 @@ void cxl_uport_init_ras_reporting(struct cxl_port *port)
 		dev_err(&port->dev, "Failed to map RAS capability.\n");
 		return;
 	}
+
+	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");
 
@@ -871,6 +906,8 @@ 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) {
@@ -887,6 +924,18 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport)
 		dev_err(dport_dev, "Failed to map RAS capability.\n");
 		return;
 	}
+
+	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");
 
-- 
2.34.1