cxl/core: Add CXL EINJ debugfs files

Export CXL helper functions in einj-cxl.c for getting/injecting
available CXL protocol error types to sysfs under kernel/debug/cxl.

The kernel/debug/cxl/einj_types file will print the available CXL
protocol errors in the same format as the available_error_types
file provided by the einj module. The
kernel/debug/cxl/$dport_dev/einj_inject file is functionally the same
as the error_type and error_inject files provided by the EINJ module,
i.e.: writing an error type into $dport_dev/einj_inject will inject
said error type into the CXL dport represented by $dport_dev.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
Link: https://lore.kernel.org/r/20240311142508.31717-4-Benjamin.Cheatham@amd.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index e59d9d37aa65..01e64b83a78c 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -3,6 +3,7 @@
 #include <linux/platform_device.h>
 #include <linux/memregion.h>
 #include <linux/workqueue.h>
+#include <linux/einj-cxl.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/module.h>
@@ -793,6 +794,40 @@ static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
 	return rc;
 }
 
+DEFINE_SHOW_ATTRIBUTE(einj_cxl_available_error_type);
+
+static int cxl_einj_inject(void *data, u64 type)
+{
+	struct cxl_dport *dport = data;
+
+	if (dport->rch)
+		return einj_cxl_inject_rch_error(dport->rcrb.base, type);
+
+	return einj_cxl_inject_error(to_pci_dev(dport->dport_dev), type);
+}
+DEFINE_DEBUGFS_ATTRIBUTE(cxl_einj_inject_fops, NULL, cxl_einj_inject,
+			 "0x%llx\n");
+
+static void cxl_debugfs_create_dport_dir(struct cxl_dport *dport)
+{
+	struct dentry *dir;
+
+	if (!einj_cxl_is_initialized())
+		return;
+
+	/*
+	 * dport_dev needs to be a PCIe port for CXL 2.0+ ports because
+	 * EINJ expects a dport SBDF to be specified for 2.0 error injection.
+	 */
+	if (!dport->rch && !dev_is_pci(dport->dport_dev))
+		return;
+
+	dir = cxl_debugfs_create_dir(dev_name(dport->dport_dev));
+
+	debugfs_create_file("einj_inject", 0200, dir, dport,
+			    &cxl_einj_inject_fops);
+}
+
 static struct cxl_port *__devm_cxl_add_port(struct device *host,
 					    struct device *uport_dev,
 					    resource_size_t component_reg_phys,
@@ -1149,6 +1184,8 @@ __devm_cxl_add_dport(struct cxl_port *port, struct device *dport_dev,
 	if (dev_is_pci(dport_dev))
 		dport->link_latency = cxl_pci_get_latency(to_pci_dev(dport_dev));
 
+	cxl_debugfs_create_dport_dir(dport);
+
 	return dport;
 }
 
@@ -2221,6 +2258,10 @@ static __init int cxl_core_init(void)
 
 	cxl_debugfs = debugfs_create_dir("cxl", NULL);
 
+	if (einj_cxl_is_initialized())
+		debugfs_create_file("einj_types", 0400, cxl_debugfs, NULL,
+				    &einj_cxl_available_error_type_fops);
+
 	cxl_mbox_init();
 
 	rc = cxl_memdev_init();