scripts: Add scripts for platform_driver remove

In Linux v6.11, the 'platform_driver' structure 'remove' callback was
updated to return void instead of 'int'. This change impacts all OOT
platform drivers and so instead of editing each manually, add a
coccinelle script to handle updating all platform drivers. This script
is ran by executing the following command ...

 $ spatch --in-place \
   --sp-file /path/to/scripts/coccinelle/platform_driver_remove.cocci
   <driver-source-directory>

Finally, add a test to the conftest script that is used to detect if the
platform driver 'remove' callback returns 'void'.

Bug 4749580

Change-Id: I53d25cc36cc3be97a6eeeb4ccbdf9b7dfda338a9
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3176834
(cherry picked from commit 24826db83f)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3202689
Reviewed-by: Brad Griffis <bgriffis@nvidia.com>
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>

scripts/coccinelle/platform_driver_remove.cocci

@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// Options: --no-includes --include-headers --smpl-spacing
+
+@match1@
+identifier p, removefn;
+@@
+struct platform_driver p = {
+	.remove = removefn,
+};
+
+@match2@
+identifier p, removefn;
+@@
+struct platform_driver p = {
+	.remove = __exit_p(removefn),
+};
+
+@match3@
+@@
+#include <nvidia/conftest.h>
+
+@fix1 depends on match1@
+identifier match1.p;
+identifier match1.removefn;
+fresh identifier removefn_wrapper = removefn ## "_wrapper";
+@@
++#if defined(NV_PLATFORM_DRIVER_STRUCT_REMOVE_RETURNS_VOID) /* Linux v6.11 */
++static inline void removefn_wrapper(struct platform_device *pdev)
++{
++	removefn(pdev);
++}
++#else
++static inline int removefn_wrapper(struct platform_device *pdev)
++{
++	return removefn(pdev);
++}
++#endif
++
+struct platform_driver p = {
+-	.remove = removefn,
++	.remove = removefn_wrapper,
+};
+
+@fix2 depends on match2@
+identifier match2.p;
+identifier match2.removefn;
+fresh identifier removefn_wrapper = removefn ## "_wrapper";
+@@
++#if defined(NV_PLATFORM_DRIVER_STRUCT_REMOVE_RETURNS_VOID) /* Linux v6.11 */
++static inline void removefn_wrapper(struct platform_device *pdev)
++{
++	removefn(pdev);
++}
++#else
++static inline int removefn_wrapper(struct platform_device *pdev)
++{
++	return removefn(pdev);
++}
++#endif
++
+struct platform_driver p = {
+-	.remove = __exit_p(removefn),
++	.remove = __exit_p(removefn_wrapper),
+};
+
+@fix3 depends on (match1 || match2) && !match3@
+@@
++#include <nvidia/conftest.h>
++
+#include <...>
+
+@fix4 depends on (match1 || match2) && (!match3 && !fix3)@
+@@
++#include <nvidia/conftest.h>
++
+#include "..."

scripts/conftest/Makefile

@@ -153,6 +153,7 @@ NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epf_alloc_space_has_epc_features_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epf_driver_struct_probe_has_id_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epc_event_ops_struct_has_core_deinit
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += pci_epc_irq_type_enum_present
+NV_CONFTEST_FUNCTION_COMPILE_TESTS += platform_driver_struct_remove_returns_void
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += register_shrinker_has_fmt_arg
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += shrinker_alloc
 NV_CONFTEST_FUNCTION_COMPILE_TESTS += slab_mem_spread

scripts/conftest/conftest.sh

@@ -7554,6 +7554,24 @@ compile_test() {
             compile_check_conftest "$CODE" "NV_PCI_EPC_EVENT_OPS_STRUCT_HAS_CORE_DEINIT" "" "types"
         ;;
 
+        platform_driver_struct_remove_returns_void)
+            #
+            # Determine if the 'platform_driver' structure 'remove' function
+            # pointer returns void.
+            #
+            # Commit 0edb555a65d1 ("platform: Make platform_driver::remove()
+            # return void") update the platform_driver structure 'remove'
+            # callback to return void instead of int.
+            #
+            CODE="
+            #include <linux/platform_device.h>
+            void conftest_platform_driver_struct_remove_returns_void(struct platform_driver *driver) {
+                void (*fn)(struct platform_device *) = driver->remove;
+            }"
+
+            compile_check_conftest "$CODE" "NV_PLATFORM_DRIVER_STRUCT_REMOVE_RETURNS_VOID" "" "types"
+        ;;
+
         register_shrinker_has_fmt_arg)
             #
             # Determine if the 'register_shrinker' function