swiotlb: support bouncing of HighMem pages
Impact: prepare the swiotlb code for HighMem struct pages This requires us to treat DMA regions in terms of page+offset rather than virtual addressing since a HighMem page may not have a mapping. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Jeremy Fitzhardinge
Ingo Molnar
parent
1b548f667c
commit
ef9b189352
122
lib/swiotlb.c
122
lib/swiotlb.c
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@ -26,6 +26,7 @@
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#include <linux/swiotlb.h>
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#include <linux/types.h>
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#include <linux/ctype.h>
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#include <linux/highmem.h>
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#include <asm/io.h>
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#include <asm/dma.h>
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@ -38,9 +39,6 @@
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#define OFFSET(val,align) ((unsigned long) \
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( (val) & ( (align) - 1)))
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#define SG_ENT_VIRT_ADDRESS(sg) (sg_virt((sg)))
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#define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg))
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#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT))
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/*
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@ -91,7 +89,10 @@ static unsigned int io_tlb_index;
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* We need to save away the original address corresponding to a mapped entry
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* for the sync operations.
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*/
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static unsigned char **io_tlb_orig_addr;
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static struct swiotlb_phys_addr {
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struct page *page;
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unsigned int offset;
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} *io_tlb_orig_addr;
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/*
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* Protect the above data structures in the map and unmap calls
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@ -150,6 +151,11 @@ int __weak swiotlb_arch_range_needs_mapping(void *ptr, size_t size)
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return 0;
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}
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static dma_addr_t swiotlb_sg_to_bus(struct scatterlist *sg)
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{
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return swiotlb_phys_to_bus(page_to_phys(sg_page(sg)) + sg->offset);
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}
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/*
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* Statically reserve bounce buffer space and initialize bounce buffer data
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* structures for the software IO TLB used to implement the DMA API.
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@ -183,7 +189,7 @@ swiotlb_init_with_default_size(size_t default_size)
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for (i = 0; i < io_tlb_nslabs; i++)
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io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
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io_tlb_index = 0;
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io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *));
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io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
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/*
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* Get the overflow emergency buffer
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@ -258,12 +264,12 @@ swiotlb_late_init_with_default_size(size_t default_size)
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io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
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io_tlb_index = 0;
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io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL,
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get_order(io_tlb_nslabs * sizeof(char *)));
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io_tlb_orig_addr = (struct swiotlb_phys_addr *)__get_free_pages(GFP_KERNEL,
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get_order(io_tlb_nslabs * sizeof(struct swiotlb_phys_addr)));
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if (!io_tlb_orig_addr)
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goto cleanup3;
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memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *));
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memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(struct swiotlb_phys_addr));
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/*
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* Get the overflow emergency buffer
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@ -312,20 +318,59 @@ static int is_swiotlb_buffer(char *addr)
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return addr >= io_tlb_start && addr < io_tlb_end;
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}
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static void
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__sync_single(char *buffer, char *dma_addr, size_t size, int dir)
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static struct swiotlb_phys_addr swiotlb_bus_to_phys_addr(char *dma_addr)
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{
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if (dir == DMA_TO_DEVICE)
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memcpy(dma_addr, buffer, size);
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else
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memcpy(buffer, dma_addr, size);
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int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
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struct swiotlb_phys_addr buffer = io_tlb_orig_addr[index];
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buffer.offset += (long)dma_addr & ((1 << IO_TLB_SHIFT) - 1);
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buffer.page += buffer.offset >> PAGE_SHIFT;
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buffer.offset &= PAGE_SIZE - 1;
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return buffer;
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}
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static void
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__sync_single(struct swiotlb_phys_addr buffer, char *dma_addr, size_t size, int dir)
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{
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if (PageHighMem(buffer.page)) {
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size_t len, bytes;
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char *dev, *host, *kmp;
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len = size;
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while (len != 0) {
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unsigned long flags;
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bytes = len;
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if ((bytes + buffer.offset) > PAGE_SIZE)
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bytes = PAGE_SIZE - buffer.offset;
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local_irq_save(flags); /* protects KM_BOUNCE_READ */
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kmp = kmap_atomic(buffer.page, KM_BOUNCE_READ);
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dev = dma_addr + size - len;
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host = kmp + buffer.offset;
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if (dir == DMA_FROM_DEVICE)
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memcpy(host, dev, bytes);
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else
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memcpy(dev, host, bytes);
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kunmap_atomic(kmp, KM_BOUNCE_READ);
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local_irq_restore(flags);
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len -= bytes;
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buffer.page++;
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buffer.offset = 0;
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}
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} else {
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void *v = page_address(buffer.page) + buffer.offset;
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if (dir == DMA_TO_DEVICE)
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memcpy(dma_addr, v, size);
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else
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memcpy(v, dma_addr, size);
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}
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}
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/*
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* Allocates bounce buffer and returns its kernel virtual address.
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*/
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static void *
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map_single(struct device *hwdev, char *buffer, size_t size, int dir)
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map_single(struct device *hwdev, struct swiotlb_phys_addr buffer, size_t size, int dir)
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{
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unsigned long flags;
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char *dma_addr;
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@ -335,6 +380,7 @@ map_single(struct device *hwdev, char *buffer, size_t size, int dir)
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unsigned long mask;
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unsigned long offset_slots;
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unsigned long max_slots;
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struct swiotlb_phys_addr slot_buf;
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mask = dma_get_seg_boundary(hwdev);
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start_dma_addr = swiotlb_virt_to_bus(io_tlb_start) & mask;
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@ -419,8 +465,13 @@ found:
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* This is needed when we sync the memory. Then we sync the buffer if
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* needed.
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*/
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for (i = 0; i < nslots; i++)
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io_tlb_orig_addr[index+i] = buffer + (i << IO_TLB_SHIFT);
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slot_buf = buffer;
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for (i = 0; i < nslots; i++) {
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slot_buf.page += slot_buf.offset >> PAGE_SHIFT;
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slot_buf.offset &= PAGE_SIZE - 1;
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io_tlb_orig_addr[index+i] = slot_buf;
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slot_buf.offset += 1 << IO_TLB_SHIFT;
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}
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if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)
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__sync_single(buffer, dma_addr, size, DMA_TO_DEVICE);
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@ -436,12 +487,12 @@ unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir)
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unsigned long flags;
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int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
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int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
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char *buffer = io_tlb_orig_addr[index];
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struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
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/*
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* First, sync the memory before unmapping the entry
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*/
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if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL)))
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if ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))
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/*
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* bounce... copy the data back into the original buffer * and
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* delete the bounce buffer.
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@ -478,10 +529,7 @@ static void
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sync_single(struct device *hwdev, char *dma_addr, size_t size,
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int dir, int target)
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{
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int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT;
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char *buffer = io_tlb_orig_addr[index];
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buffer += ((unsigned long)dma_addr & ((1 << IO_TLB_SHIFT) - 1));
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struct swiotlb_phys_addr buffer = swiotlb_bus_to_phys_addr(dma_addr);
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switch (target) {
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case SYNC_FOR_CPU:
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@ -529,7 +577,10 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size,
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* swiotlb_map_single(), which will grab memory from
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* the lowest available address range.
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*/
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ret = map_single(hwdev, NULL, size, DMA_FROM_DEVICE);
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struct swiotlb_phys_addr buffer;
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buffer.page = virt_to_page(NULL);
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buffer.offset = 0;
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ret = map_single(hwdev, buffer, size, DMA_FROM_DEVICE);
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if (!ret)
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return NULL;
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}
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@ -597,6 +648,7 @@ swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
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{
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dma_addr_t dev_addr = swiotlb_virt_to_bus(ptr);
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void *map;
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struct swiotlb_phys_addr buffer;
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BUG_ON(dir == DMA_NONE);
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/*
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@ -611,7 +663,9 @@ swiotlb_map_single_attrs(struct device *hwdev, void *ptr, size_t size,
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/*
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* Oh well, have to allocate and map a bounce buffer.
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*/
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map = map_single(hwdev, ptr, size, dir);
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buffer.page = virt_to_page(ptr);
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buffer.offset = (unsigned long)ptr & ~PAGE_MASK;
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map = map_single(hwdev, buffer, size, dir);
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if (!map) {
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swiotlb_full(hwdev, size, dir, 1);
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map = io_tlb_overflow_buffer;
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@ -756,18 +810,20 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
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int dir, struct dma_attrs *attrs)
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{
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struct scatterlist *sg;
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void *addr;
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struct swiotlb_phys_addr buffer;
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dma_addr_t dev_addr;
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int i;
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BUG_ON(dir == DMA_NONE);
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for_each_sg(sgl, sg, nelems, i) {
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addr = SG_ENT_VIRT_ADDRESS(sg);
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dev_addr = swiotlb_virt_to_bus(addr);
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dev_addr = swiotlb_sg_to_bus(sg);
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if (range_needs_mapping(sg_virt(sg), sg->length) ||
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address_needs_mapping(hwdev, dev_addr, sg->length)) {
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void *map = map_single(hwdev, addr, sg->length, dir);
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void *map;
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buffer.page = sg_page(sg);
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buffer.offset = sg->offset;
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map = map_single(hwdev, buffer, sg->length, dir);
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if (!map) {
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/* Don't panic here, we expect map_sg users
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to do proper error handling. */
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@ -807,11 +863,11 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
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BUG_ON(dir == DMA_NONE);
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for_each_sg(sgl, sg, nelems, i) {
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if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
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if (sg->dma_address != swiotlb_sg_to_bus(sg))
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unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
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sg->dma_length, dir);
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else if (dir == DMA_FROM_DEVICE)
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dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
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dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
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}
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}
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EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
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@ -840,11 +896,11 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
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BUG_ON(dir == DMA_NONE);
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for_each_sg(sgl, sg, nelems, i) {
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if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
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if (sg->dma_address != swiotlb_sg_to_bus(sg))
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sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
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sg->dma_length, dir, target);
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else if (dir == DMA_FROM_DEVICE)
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dma_mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length);
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dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
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}
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}
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