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iommu: bcm2712-iommu: Add locking; fix address offset; tidy #6939

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Merged
merged 1 commit into from
Jul 6, 2025
+34 −18
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iommu: bcm2712-iommu: Add locking; fix address offset; tidy #6939

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52 changes: 34 additions & 18 deletions drivers/iommu/bcm2712-iommu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -244,8 +244,10 @@ static int bcm2712_iommu_map(struct iommu_domain *domain, unsigned long iova,
u32 entry = MMMU_PTE_VALID | (pa >> MMU_PAGE_SHIFT);
u32 align = (u32)(iova | pa | bytes);
unsigned int p;
unsigned long flags;

/* Reject if at least the first page is not within our aperture */
/* Reject if not entirely within our aperture (should never happen) */
bytes *= count;
if (iova < mmu->dma_iova_offset + APERTURE_BASE ||
iova + bytes > mmu->dma_iova_offset + APERTURE_TOP) {
dev_warn(mmu->dev, "%s: iova=0x%lx pa=0x%llx bytes=0x%lx OUT OF RANGE\n",
Expand All @@ -267,14 +269,14 @@ static int bcm2712_iommu_map(struct iommu_domain *domain, unsigned long iova,
entry |= MMMU_PTE_WRITEABLE;

/* Ensure tables are cache-coherent with CPU */
spin_lock_irqsave(&mmu->hw_lock, flags);
if (!mmu->dirty) {
dma_sync_sgtable_for_cpu(mmu->dev, mmu->sgt, DMA_TO_DEVICE);
mmu->dirty = true;
}

/* Make iova relative to table base; amalgamate count pages */
/* Make iova relative to table base */
iova -= (mmu->dma_iova_offset + APERTURE_BASE);
bytes = min(APERTURE_SIZE - iova, count * bytes);

/* Iterate over table by smallest native IOMMU page size */
for (p = iova >> MMU_PAGE_SHIFT;
Expand All @@ -283,6 +285,7 @@ static int bcm2712_iommu_map(struct iommu_domain *domain, unsigned long iova,
mmu->tables[p] = entry++;
}

spin_unlock_irqrestore(&mmu->hw_lock, flags);
*mapped = bytes;

return 0;
Expand All @@ -293,31 +296,27 @@ static size_t bcm2712_iommu_unmap(struct iommu_domain *domain, unsigned long iov
struct iommu_iotlb_gather *gather)
{
struct bcm2712_iommu *mmu = domain_to_mmu(domain);
unsigned long flags;
unsigned int p;

/* Reject if not entirely within our aperture (should never happen) */
bytes *= count;
if (iova < mmu->dma_iova_offset + APERTURE_BASE ||
iova + bytes > mmu->dma_iova_offset + APERTURE_TOP)
return 0;

/* Record just the lower and upper bounds in "gather" */
if (gather) {
bool empty = (gather->end <= gather->start);

if (empty || gather->start < iova)
gather->start = iova;
if (empty || gather->end < iova + bytes)
gather->end = iova + bytes;
}
spin_lock_irqsave(&mmu->hw_lock, flags);
iommu_iotlb_gather_add_range(gather, iova, bytes);

/* Ensure tables are cache-coherent with CPU */
if (!mmu->dirty) {
dma_sync_sgtable_for_cpu(mmu->dev, mmu->sgt, DMA_TO_DEVICE);
mmu->dirty = true;
}

/* Make iova relative to table base; amalgamate count pages */
/* Make iova relative to table base */
iova -= (mmu->dma_iova_offset + APERTURE_BASE);
bytes = min(APERTURE_SIZE - iova, count * bytes);

/* Clear table entries, this marks the addresses as illegal */
for (p = iova >> MMU_PAGE_SHIFT;
Expand All @@ -327,20 +326,22 @@ static size_t bcm2712_iommu_unmap(struct iommu_domain *domain, unsigned long iov
mmu->tables[p] = 0;
}

spin_unlock_irqrestore(&mmu->hw_lock, flags);
return bytes;
}

static int bcm2712_iommu_sync_range(struct iommu_domain *domain,
unsigned long iova, size_t size)
{
struct bcm2712_iommu *mmu = domain_to_mmu(domain);
unsigned long iova_end;
unsigned long flags, iova_end;
unsigned int i, p4;

if (!mmu || !mmu->dirty)
return 0;

/* Ensure tables are cleaned from CPU cache or write-buffer */
spin_lock_irqsave(&mmu->hw_lock, flags);
dma_sync_sgtable_for_device(mmu->dev, mmu->sgt, DMA_TO_DEVICE);
mmu->dirty = false;

Expand Down Expand Up @@ -384,19 +385,26 @@ static int bcm2712_iommu_sync_range(struct iommu_domain *domain,
}
}

spin_unlock_irqrestore(&mmu->hw_lock, flags);
return 0;
}

static void bcm2712_iommu_sync(struct iommu_domain *domain,
struct iommu_iotlb_gather *gather)
{
bcm2712_iommu_sync_range(domain, gather->start,
gather->end - gather->start);
if (gather->end)
bcm2712_iommu_sync_range(domain, gather->start,
gather->end - gather->start + 1);
}

static void bcm2712_iommu_sync_all(struct iommu_domain *domain)
{
bcm2712_iommu_sync_range(domain, APERTURE_BASE, APERTURE_SIZE);
struct bcm2712_iommu *mmu = domain_to_mmu(domain);

if (mmu)
bcm2712_iommu_sync_range(domain,
mmu->dma_iova_offset + APERTURE_BASE,
APERTURE_SIZE);
}

static phys_addr_t bcm2712_iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
Expand All @@ -406,9 +414,17 @@ static phys_addr_t bcm2712_iommu_iova_to_phys(struct iommu_domain *domain, dma_a

iova -= mmu->dma_iova_offset;
if (iova >= APERTURE_BASE && iova < APERTURE_TOP) {
unsigned long flags;
phys_addr_t addr;

spin_lock_irqsave(&mmu->hw_lock, flags);
p = (iova - APERTURE_BASE) >> MMU_PAGE_SHIFT;
p = mmu->tables[p] & 0x0FFFFFFFu;
return (((phys_addr_t)p) << MMU_PAGE_SHIFT) + (iova & (MMU_PAGE_SIZE - 1u));
addr = (((phys_addr_t)p) << MMU_PAGE_SHIFT) +
(iova & (MMU_PAGE_SIZE - 1u));

spin_unlock_irqrestore(&mmu->hw_lock, flags);
return addr;
} else if (iova < APERTURE_BASE) {
return (phys_addr_t)iova;
} else {
Expand Down