1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/iommu/bcm2712-iommu-cache.c b/drivers/iommu/bcm2712-iommu-cache.c
new file mode 100644
index 000000000000..fdea69f5370b
--- /dev/null
+++ b/drivers/iommu/bcm2712-iommu-cache.c
@@ -0,0 +1,77 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * IOMMU driver for BCM2712
+ *
+ * Copyright (c) 2023 Raspberry Pi Ltd.
+ */
+
+#include "bcm2712-iommu.h"
+
+#include <linux/err.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define MMUC_CONTROL_ENABLE   1
+#define MMUC_CONTROL_FLUSH    2
+#define MMUC_CONTROL_FLUSHING 4
+
+void bcm2712_iommu_cache_flush(struct bcm2712_iommu_cache *cache)
+{
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&cache->hw_lock, flags);
+	if (cache->reg_base) {
+		/* Enable and flush the TLB cache */
+		writel(MMUC_CONTROL_ENABLE | MMUC_CONTROL_FLUSH,
+		       cache->reg_base);
+
+		/* Wait for flush to complete: it should be very quick */
+		for (i = 0; i < 1024; i++) {
+			if (!(MMUC_CONTROL_FLUSHING & readl(cache->reg_base)))
+				break;
+			cpu_relax();
+		}
+	}
+	spin_unlock_irqrestore(&cache->hw_lock, flags);
+}
+
+static int bcm2712_iommu_cache_probe(struct platform_device *pdev)
+{
+	struct bcm2712_iommu_cache *cache;
+
+	dev_info(&pdev->dev, __func__);
+	cache = devm_kzalloc(&pdev->dev, sizeof(*cache), GFP_KERNEL);
+	if (!cache)
+		return -ENOMEM;
+
+	cache->dev = &pdev->dev;
+	platform_set_drvdata(pdev, cache);
+	spin_lock_init(&cache->hw_lock);
+
+	/* Get IOMMUC registers; we only use the first register (IOMMUC_CTRL) */
+	cache->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(cache->reg_base)) {
+		dev_err(&pdev->dev, "Failed to get IOMMU Cache registers address\n");
+		cache->reg_base = NULL;
+	}
+	return 0;
+}
+
+static const struct of_device_id bcm2712_iommu_cache_of_match[] = {
+	{
+		. compatible = "brcm,bcm2712-iommuc"
+	},
+	{ /* sentinel */ },
+};
+
+static struct platform_driver bcm2712_iommu_cache_driver = {
+	.probe = bcm2712_iommu_cache_probe,
+	.driver = {
+		.name = "bcm2712-iommu-cache",
+		.of_match_table = bcm2712_iommu_cache_of_match
+	},
+};
+
+builtin_platform_driver(bcm2712_iommu_cache_driver);