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// SPDX-License-Identifier: GPL-2.0-only
/*
* IOMMU driver for BCM2712 TLB cache
*
* Copyright (c) 2023 Raspberry Pi Ltd.
* Copyright (c) 2026 Daniel Drake
*
* The BCM2712 IOMMUC is a centralized TLB which accelerates address translation
* across the SoC's IOMMU devices. If an address mapping is not found in the
* IOMMU's local TLB cache, then this IOMMUC is consulted. The IOMMUC must be
* explicitly invalidated when modifying or unmapping IOMMU page tables.
*/
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/err.h>
#include <linux/iopoll.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include "bcm2712-iommu-cache.h"
struct bcm2712_iommu_cache {
struct device *dev;
spinlock_t hw_lock;
void __iomem *reg_base;
};
#define MMUC_CONTROL_ENABLE BIT(0)
#define MMUC_CONTROL_FLUSH BIT(1)
#define MMUC_CONTROL_FLUSHING BIT(2)
void bcm2712_iommu_cache_flush(struct bcm2712_iommu_cache *cache)
{
u32 val;
int ret;
scoped_guard(spinlock_irqsave, &cache->hw_lock) {
writel(MMUC_CONTROL_ENABLE | MMUC_CONTROL_FLUSH,
cache->reg_base);
ret = readl_poll_timeout_atomic(cache->reg_base, val,
!(val & MMUC_CONTROL_FLUSHING),
0, 50);
}
if (ret)
dev_err_ratelimited(cache->dev, "cache flush timed out\n");
}
static int bcm2712_iommu_cache_probe(struct platform_device *pdev)
{
struct bcm2712_iommu_cache *cache;
cache = devm_kzalloc(&pdev->dev, sizeof(*cache), GFP_KERNEL);
if (!cache)
return -ENOMEM;
cache->dev = &pdev->dev;
spin_lock_init(&cache->hw_lock);
cache->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(cache->reg_base))
return PTR_ERR(cache->reg_base);
platform_set_drvdata(pdev, cache);
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,
.suppress_bind_attrs = true,
},
};
builtin_platform_driver(bcm2712_iommu_cache_driver);
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