[PATCH v12 10/12] 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 and
CXL Reset Memory Clear 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 b2879a6be5f8..157f06c576e9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -35,6 +35,7 @@
 #include <linux/aer.h>
 #include <linux/bitfield.h>
 #include <linux/suspend.h>
+#include <cxl/cxl.h>
 #include "pci.h"
 
 DEFINE_MUTEX(pci_slot_mutex);
@@ -5145,6 +5146,7 @@ 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 84d058b1b492..074767c7afc4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -52,7 +52,7 @@
 			       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