[PATCH v8 09/10] PCI/CXL: Expose CXL Reset as a PCI reset method

[Srirangan Madhavan <smadhavan@nvidia.com>]

Add the CXL Reset helper to the PCI reset-method table so userspace can
select it through the existing reset_method ABI.

Advertise the method for Type 2 CXL devices that report CXL Reset
support in the CXL Device DVSEC and pass the function-scope check. Reset
execution requires cached HDM decoder state for the target so affected
ranges can be validated and HDM programming can be restored. If that
state is unavailable at reset time, return -ENOTTY so PCI can try the
next reset method.

Signed-off-by: Srirangan Madhavan <smadhavan@nvidia.com>
---
 drivers/pci/pci.c   | 2 ++
 include/linux/pci.h | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d34266651ad0..7521e705f718 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -33,6 +33,7 @@
 #include <asm/dma.h>
 #include <linux/aer.h>
 #include <linux/bitfield.h>
+#include <cxl/cxl.h>
 #include "pci.h"
 
 DEFINE_MUTEX(pci_slot_mutex);
@@ -5060,6 +5061,7 @@ const struct pci_reset_fn_method pci_reset_fn_methods[] = {
 	{ },
 	{ pci_dev_specific_reset, .name = "device_specific" },
 	{ pci_dev_acpi_reset, .name = "acpi" },
+	{ cxl_reset_function, .name = "cxl_reset" },
 	{ pcie_reset_flr, .name = "flr" },
 	{ pci_af_flr, .name = "af_flr" },
 	{ pci_pm_reset, .name = "pm" },
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7db2daf8597c..7d6f1adab27c 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -51,7 +51,7 @@
 			       PCI_STATUS_PARITY)
 
 /* Number of reset methods used in pci_reset_fn_methods array in pci.c */
-#define PCI_NUM_RESET_METHODS 8
+#define PCI_NUM_RESET_METHODS 9
 
 #define PCI_RESET_PROBE		true
 #define PCI_RESET_DO_RESET	false
-- 
2.43.0