[PATCH 3/5] swiotlb: Add alloc and free APIs

Srivatsa Vaddagiri
2020-04-28T12:05:53Z

Move the memory allocation and free portion of swiotlb driver
into independent routines. They will be useful for drivers that
need swiotlb driver to just allocate/free memory chunks and not
additionally bounce memory.

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
---
include/linux/swiotlb.h | 17 ++++++
kernel/dma/swiotlb.c | 151 ++++++++++++++++++++++++++++--------------------
2 files changed, 106 insertions(+), 62 deletions(-)

diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h
index c634b4d..957697e 100644
--- a/include/linux/swiotlb.h
+++ b/include/linux/swiotlb.h
@@ -186,6 +186,10 @@ void __init swiotlb_exit(void);
unsigned int swiotlb_max_segment(void);
size_t swiotlb_max_mapping_size(struct device *dev);
bool is_swiotlb_active(void);
+extern phys_addr_t swiotlb_alloc(struct swiotlb_pool *pool, size_t alloc_size,
+ unsigned long tbl_dma_addr, unsigned long mask);
+extern void swiotlb_free(struct swiotlb_pool *pool,
+ phys_addr_t tlb_addr, size_t alloc_size);
#else
#define swiotlb_force SWIOTLB_NO_FORCE

@@ -219,6 +223,19 @@ static inline bool is_swiotlb_active(void)
{
return false;
}
+
+static inline phys_addr_t swiotlb_alloc(struct swiotlb_pool *pool,
+ size_t alloc_size, unsigned long tbl_dma_addr,
+ unsigned long mask)
+{
+ return DMA_MAPPING_ERROR;
+}
+
+static inline void swiotlb_free(struct swiotlb_pool *pool,
+ phys_addr_t tlb_addr, size_t alloc_size)
+{
+}
+
#endif /* CONFIG_SWIOTLB */

extern void swiotlb_print_info(void);
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 8cf0b57..7411ce5 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -444,37 +444,14 @@ static inline void *tlb_vaddr(struct swiotlb_pool *pool, phys_addr_t tlb_addr)
return pool->io_tlb_vstart + (tlb_addr - pool->io_tlb_start);
}

-phys_addr_t _swiotlb_tbl_map_single(struct swiotlb_pool *pool,
- struct device *hwdev,
- dma_addr_t tbl_dma_addr,
- phys_addr_t orig_addr,
- size_t mapping_size,
- size_t alloc_size,
- enum dma_data_direction dir,
- unsigned long attrs)
+phys_addr_t swiotlb_alloc(struct swiotlb_pool *pool, size_t alloc_size,
+ unsigned long tbl_dma_addr, unsigned long mask)
{
unsigned long flags;
phys_addr_t tlb_addr;
- unsigned int nslots, stride, index, wrap;
- int i;
- unsigned long mask;
+ unsigned int i, nslots, stride, index, wrap;
unsigned long offset_slots;
unsigned long max_slots;
- unsigned long tmp_io_tlb_used;
-
- if (pool->no_iotlb_memory)
- panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
-
- if (mem_encrypt_active())
- pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
-
- if (mapping_size > alloc_size) {
- dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
- mapping_size, alloc_size);
- return (phys_addr_t)DMA_MAPPING_ERROR;
- }
-
- mask = dma_get_seg_boundary(hwdev);

tbl_dma_addr &= mask;

@@ -555,54 +532,23 @@ phys_addr_t _swiotlb_tbl_map_single(struct swiotlb_pool *pool,
} while (index != wrap);

not_found:
- tmp_io_tlb_used = pool->io_tlb_used;
-
spin_unlock_irqrestore(&pool->io_tlb_lock, flags);
- if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
- dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n",
- alloc_size, pool->io_tlb_nslabs, tmp_io_tlb_used);
return (phys_addr_t)DMA_MAPPING_ERROR;
+
found:
pool->io_tlb_used += nslots;
spin_unlock_irqrestore(&pool->io_tlb_lock, flags);

- /*
- * Save away the mapping from the original address to the DMA address.
- * This is needed when we sync the memory. Then we sync the buffer if
- * needed.
- */
- for (i = 0; i < nslots; i++)
- pool->io_tlb_orig_addr[index+i] = orig_addr +
- (i << IO_TLB_SHIFT);
- if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
- (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
- swiotlb_bounce(orig_addr, tlb_vaddr(pool, tlb_addr),
- mapping_size, DMA_TO_DEVICE);
-
return tlb_addr;
}

-/*
- * tlb_addr is the physical address of the bounce buffer to unmap.
- */
-void _swiotlb_tbl_unmap_single(struct swiotlb_pool *pool,
- struct device *hwdev, phys_addr_t tlb_addr,
- size_t mapping_size, size_t alloc_size,
- enum dma_data_direction dir, unsigned long attrs)
+void swiotlb_free(struct swiotlb_pool *pool,
+ phys_addr_t tlb_addr, size_t alloc_size)
{
unsigned long flags;
- int i, count, nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ int i, count;
+ int nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
int index = (tlb_addr - pool->io_tlb_start) >> IO_TLB_SHIFT;
- phys_addr_t orig_addr = pool->io_tlb_orig_addr[index];
-
- /*
- * First, sync the memory before unmapping the entry
- */
- if (orig_addr != INVALID_PHYS_ADDR &&
- !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
- ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
- swiotlb_bounce(orig_addr, tlb_vaddr(pool, tlb_addr),
- mapping_size, DMA_FROM_DEVICE);

/*
* Return the buffer to the free list by setting the corresponding
@@ -636,6 +582,87 @@ void _swiotlb_tbl_unmap_single(struct swiotlb_pool *pool,
spin_unlock_irqrestore(&pool->io_tlb_lock, flags);
}

+phys_addr_t _swiotlb_tbl_map_single(struct swiotlb_pool *pool,
+ struct device *hwdev,
+ dma_addr_t tbl_dma_addr,
+ phys_addr_t orig_addr,
+ size_t mapping_size,
+ size_t alloc_size,
+ enum dma_data_direction dir,
+ unsigned long attrs)
+{
+ phys_addr_t tlb_addr;
+ unsigned int nslots, index;
+ int i;
+ unsigned long mask;
+
+ if (pool->no_iotlb_memory)
+ panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
+
+ if (mem_encrypt_active())
+ pr_warn_once("Memory encryption is active and system is using DMA bounce buffers\n");
+
+ if (mapping_size > alloc_size) {
+ dev_warn_once(hwdev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)",
+ mapping_size, alloc_size);
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+ }
+
+ mask = dma_get_seg_boundary(hwdev);
+
+ tlb_addr = swiotlb_alloc(pool, alloc_size, tbl_dma_addr, mask);
+
+ if (tlb_addr == DMA_MAPPING_ERROR) {
+ if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
+ dev_warn(hwdev, "swiotlb buffer is full (sz: %zd "
+ "bytes), total %lu (slots), used %lu (slots)\n",
+ alloc_size, pool->io_tlb_nslabs,
+ pool->io_tlb_used);
+ return (phys_addr_t)DMA_MAPPING_ERROR;
+ }
+
+ nslots = ALIGN(alloc_size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
+ index = (tlb_addr - pool->io_tlb_start) >> IO_TLB_SHIFT;
+
+ /*
+ * Save away the mapping from the original address to the DMA address.
+ * This is needed when we sync the memory. Then we sync the buffer if
+ * needed.
+ */
+ for (i = 0; i < nslots; i++)
+ pool->io_tlb_orig_addr[index+i] = orig_addr +
+ (i << IO_TLB_SHIFT);
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+ (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL))
+ swiotlb_bounce(orig_addr, tlb_vaddr(pool, tlb_addr),
+ mapping_size, DMA_TO_DEVICE);
+
+ return tlb_addr;
+}
+
+/*
+ * tlb_addr is the physical address of the bounce buffer to unmap.
+ */
+void _swiotlb_tbl_unmap_single(struct swiotlb_pool *pool,
+ struct device *hwdev, phys_addr_t tlb_addr,
+ size_t mapping_size, size_t alloc_size,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ int index = (tlb_addr - pool->io_tlb_start) >> IO_TLB_SHIFT;
+ phys_addr_t orig_addr = pool->io_tlb_orig_addr[index];
+
+ /*
+ * First, sync the memory before unmapping the entry
+ */
+ if (orig_addr != INVALID_PHYS_ADDR &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC) &&
+ ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
+ swiotlb_bounce(orig_addr, tlb_vaddr(pool, tlb_addr),
+ mapping_size, DMA_FROM_DEVICE);
+
+ swiotlb_free(pool, tlb_addr, alloc_size);
+}
+
void _swiotlb_tbl_sync_single(struct swiotlb_pool *pool,
struct device *hwdev, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir,
--
2.7.4

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