Split asustor.c into asustor_main.c and asustor_gpl2.c

asustor_main.c is licensed under GPLv2 or later, while asustor_gpl2.c
is licensed under GPLv2 only.
dmi_matches() is moved from asustor(_main).c to asustor_gpl2.c, because
it's copied from drivers/firmware/dmi_scan.c which is released under
GPLv2 only.

asustor.c had to be renamed to asustor_main.c, because apparently the
kernel build system only supports a source file with the same name as
the module if that module is built only from that file.

I also bumped the DRIVER_VERSION (used for DKMS) from v0.1 to v0.2
to hopefully avoid conflicts due to all these changes

Makefile

@@ -3,7 +3,7 @@ KERNEL_MODULES := /lib/modules/$(TARGET)
 KERNEL_BUILD   := $(KERNEL_MODULES)/build
 SYSTEM_MAP     := /boot/System.map-$(TARGET)
 DRIVER         := asustor asustor_it87 asustor_gpio_it87
-DRIVER_VERSION := v0.1
+DRIVER_VERSION := v0.2
 #DRIVER_VERSION ?= $(shell git describe --long)
 
 # DKMS
@@ -17,6 +17,8 @@ asustor_gpio_it87_DEST_DIR = $(KERNEL_MODULES)/kernel/drivers/gpio
 
 obj-m  := $(patsubst %,%.o,$(DRIVER))
 obj-ko := $(patsubst %,%.ko,$(DRIVER))
+# asustor.o is built from two source files for license reasons
+asustor-y := asustor_main.o asustor_gpl2.o
 
 all: modules
 
@@ -38,8 +40,9 @@ dkms:
 	@mkdir -p $(DKMS_ROOT_PATH_ASUSTOR)
 	@echo "obj-m := asustor.o" >>$(DKMS_ROOT_PATH_ASUSTOR)/Makefile
 	@echo "obj-ko := asustor.ko" >>$(DKMS_ROOT_PATH_ASUSTOR)/Makefile
+	@echo "asustor-y := asustor_main.o asustor_gpl2.o" >>$(DKMS_ROOT_PATH_ASUSTOR)/Makefile
 	@cp dkms.conf $(DKMS_ROOT_PATH_ASUSTOR)
-	@cp asustor.c $(DKMS_ROOT_PATH_ASUSTOR)
+	@cp asustor_main.c asustor_gpl2.c $(DKMS_ROOT_PATH_ASUSTOR)
 	@sed -i -e '/^PACKAGE_VERSION=/ s/=.*/=\"$(DRIVER_VERSION)\"/' $(DKMS_ROOT_PATH_ASUSTOR)/dkms.conf
 
 	@mkdir -p $(DKMS_ROOT_PATH_ASUSTOR_IT87)

asustor_gpl2.c

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * asustor_gpl2.c - Functions used by asustor_main.c (for asustor.ko) that were copied from the
+ *                  Linux kernel and are licensed under GPLv2 ONLY, instead of GPLv2 or later.
+ */
+
+#include <linux/dmi.h>
+
+bool asustor_dmi_matches(const struct dmi_system_id *dmi);
+
+/**
+ *	dmi_matches - check if dmi_system_id structure matches system DMI data
+ *	@dmi: pointer to the dmi_system_id structure to check
+ */
+// copied from dmi_matches() in Linux 6.11.2 drivers/firmware/dmi_scan.c where it's private (static)
+// with only one small change (dmi_val = dmi_get_system_info(s) instead of dmi_ident[s])
+bool asustor_dmi_matches(const struct dmi_system_id *dmi)
+{
+	int i;
+	const char *dmi_val;
+
+	for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
+		int s = dmi->matches[i].slot;
+		if (s == DMI_NONE)
+			break;
+		if (s == DMI_OEM_STRING) {
+			/* DMI_OEM_STRING must be exact match */
+			const struct dmi_device *valid;
+
+			valid = dmi_find_device(DMI_DEV_TYPE_OEM_STRING,
+			                        dmi->matches[i].substr, NULL);
+			if (valid)
+				continue;
+		} else if ((dmi_val = dmi_get_system_info(s)) != NULL) {
+			if (dmi->matches[i].exact_match) {
+				if (!strcmp(dmi_val, dmi->matches[i].substr))
+					continue;
+			} else {
+				if (strstr(dmi_val, dmi->matches[i].substr))
+					continue;
+			}
+		}
+
+		/* No match */
+		return false;
+	}
+	return true;
+}

asustor.c → asustor_main.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
- * asustor.c - Platform driver for ASUSTOR NAS hardware
+ * asustor_main.c - main part of asustor.ko, a platform driver for ASUSTOR NAS hardware
+ *                  (the other part is in asustor_gpl2.c which is GPL-2.0-only)
  *
  * Copyright (C) 2021 Mathias Fredriksson <[email protected]>
  */
@@ -408,45 +409,6 @@ static struct gpio_chip *find_chip_by_name(const char *name)
 }
 #endif
 
-/**
- *	dmi_matches - check if dmi_system_id structure matches system DMI data
- *	@dmi: pointer to the dmi_system_id structure to check
- */
-// copied from dmi_matches() in Linux 6.11.2 drivers/firmware/dmi_scan.c where it's private (static)
-// with only one small change (dmi_val = dmi_get_system_info(s) instead of dmi_ident[s])
-static bool dmi_matches(const struct dmi_system_id *dmi)
-{
-	int i;
-	const char *dmi_val;
-
-	for (i = 0; i < ARRAY_SIZE(dmi->matches); i++) {
-		int s = dmi->matches[i].slot;
-		if (s == DMI_NONE)
-			break;
-		if (s == DMI_OEM_STRING) {
-			/* DMI_OEM_STRING must be exact match */
-			const struct dmi_device *valid;
-
-			valid = dmi_find_device(DMI_DEV_TYPE_OEM_STRING,
-			                        dmi->matches[i].substr, NULL);
-			if (valid)
-				continue;
-		} else if ((dmi_val = dmi_get_system_info(s)) != NULL) {
-			if (dmi->matches[i].exact_match) {
-				if (!strcmp(dmi_val, dmi->matches[i].substr))
-					continue;
-			} else {
-				if (strstr(dmi_val, dmi->matches[i].substr))
-					continue;
-			}
-		}
-
-		/* No match */
-		return false;
-	}
-	return true;
-}
-
 // How many PCI(e) devices with given vendor/device IDs exist in this system?
 static int count_pci_device_instances(unsigned int vendor, unsigned int device)
 {
@@ -492,6 +454,10 @@ static bool pci_devices_match(const struct asustor_driver_data *sys)
 	return true;
 }
 
+// returns true if dmi->matches match on the current system
+// implemented in asustor_gpl2.c
+extern bool asustor_dmi_matches(const struct dmi_system_id *dmi);
+
 // find out which ASUSTOR system this is, based on asustor_systems[], including
 // their linked asustor_driver_data's pci_matches
 // returns NULL if this isn't a known system
@@ -509,7 +475,7 @@ static const struct dmi_system_id *find_matching_asustor_system(void)
 			break;
 		}
 
-		if (!dmi_matches(sys)) {
+		if (!asustor_dmi_matches(sys)) {
 			continue;
 		}