Revert "iommu/arm-smmu: Make arm-smmu explicitly non-modular"

This reverts commit addb672f20.

Let's get the SMMU driver building as a module, which means putting
back some dead code that we used to carry.

Signed-off-by: Will Deacon <will@kernel.org>
Tested-by: John Garry <john.garry@huawei.com> # smmu v3
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/arm-smmu.c

@@ -27,8 +27,7 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/iopoll.h>
-#include <linux/init.h>
-#include <linux/moduleparam.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
@@ -60,10 +59,6 @@
 #define MSI_IOVA_LENGTH			0x100000
 
 static int force_stage;
-/*
- * not really modular, but the easiest way to keep compat with existing
- * bootargs behaviour is to continue using module_param() here.
- */
 module_param(force_stage, int, S_IRUGO);
 MODULE_PARM_DESC(force_stage,
 	"Force SMMU mappings to be installed at a particular stage of translation. A value of '1' or '2' forces the corresponding stage. All other values are ignored (i.e. no stage is forced). Note that selecting a specific stage will disable support for nested translation.");
@@ -1911,6 +1906,7 @@ static const struct of_device_id arm_smmu_of_match[] = {
 	{ .compatible = "qcom,smmu-v2", .data = &qcom_smmuv2 },
 	{ },
 };
+MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
 
 #ifdef CONFIG_ACPI
 static int acpi_smmu_get_data(u32 model, struct arm_smmu_device *smmu)
@@ -2196,12 +2192,12 @@ static int arm_smmu_legacy_bus_init(void)
 }
 device_initcall_sync(arm_smmu_legacy_bus_init);
 
-static void arm_smmu_device_shutdown(struct platform_device *pdev)
+static int arm_smmu_device_remove(struct platform_device *pdev)
 {
 	struct arm_smmu_device *smmu = platform_get_drvdata(pdev);
 
 	if (!smmu)
-		return;
+		return -ENODEV;
 
 	if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
 		dev_err(&pdev->dev, "removing device with active domains!\n");
@@ -2217,6 +2213,12 @@ static void arm_smmu_device_shutdown(struct platform_device *pdev)
 		clk_bulk_disable(smmu->num_clks, smmu->clks);
 
 	clk_bulk_unprepare(smmu->num_clks, smmu->clks);
+	return 0;
+}
+
+static void arm_smmu_device_shutdown(struct platform_device *pdev)
+{
+	arm_smmu_device_remove(pdev);
 }
 
 static int __maybe_unused arm_smmu_runtime_resume(struct device *dev)
@@ -2266,12 +2268,16 @@ static const struct dev_pm_ops arm_smmu_pm_ops = {
 
 static struct platform_driver arm_smmu_driver = {
 	.driver	= {
-		.name			= "arm-smmu",
-		.of_match_table		= of_match_ptr(arm_smmu_of_match),
-		.pm			= &arm_smmu_pm_ops,
-		.suppress_bind_attrs	= true,
+		.name		= "arm-smmu",
+		.of_match_table	= of_match_ptr(arm_smmu_of_match),
+		.pm		= &arm_smmu_pm_ops,
 	},
 	.probe	= arm_smmu_device_probe,
+	.remove	= arm_smmu_device_remove,
 	.shutdown = arm_smmu_device_shutdown,
 };
-builtin_platform_driver(arm_smmu_driver);
+module_platform_driver(arm_smmu_driver);
+
+MODULE_DESCRIPTION("IOMMU API for ARM architected SMMU implementations");
+MODULE_AUTHOR("Will Deacon <will.deacon@arm.com>");
+MODULE_LICENSE("GPL v2");