diff options
Diffstat (limited to 'kernel/dma/swiotlb.c')
| -rw-r--r-- | kernel/dma/swiotlb.c | 1087 |
1 files changed, 1087 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c new file mode 100644 index 000000000000..04b68d9dffac --- /dev/null +++ b/kernel/dma/swiotlb.c @@ -0,0 +1,1087 @@ +/* + * Dynamic DMA mapping support. + * + * This implementation is a fallback for platforms that do not support + * I/O TLBs (aka DMA address translation hardware). + * Copyright (C) 2000 Asit Mallick <Asit.K.Mallick@intel.com> + * Copyright (C) 2000 Goutham Rao <goutham.rao@intel.com> + * Copyright (C) 2000, 2003 Hewlett-Packard Co + * David Mosberger-Tang <davidm@hpl.hp.com> + * + * 03/05/07 davidm Switch from PCI-DMA to generic device DMA API. + * 00/12/13 davidm Rename to swiotlb.c and add mark_clean() to avoid + * unnecessary i-cache flushing. + * 04/07/.. ak Better overflow handling. Assorted fixes. + * 05/09/10 linville Add support for syncing ranges, support syncing for + * DMA_BIDIRECTIONAL mappings, miscellaneous cleanup. + * 08/12/11 beckyb Add highmem support + */ + +#include <linux/cache.h> +#include <linux/dma-direct.h> +#include <linux/mm.h> +#include <linux/export.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/swiotlb.h> +#include <linux/pfn.h> +#include <linux/types.h> +#include <linux/ctype.h> +#include <linux/highmem.h> +#include <linux/gfp.h> +#include <linux/scatterlist.h> +#include <linux/mem_encrypt.h> +#include <linux/set_memory.h> + +#include <asm/io.h> +#include <asm/dma.h> + +#include <linux/init.h> +#include <linux/bootmem.h> +#include <linux/iommu-helper.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/swiotlb.h> + +#define OFFSET(val,align) ((unsigned long) \ + ( (val) & ( (align) - 1))) + +#define SLABS_PER_PAGE (1 << (PAGE_SHIFT - IO_TLB_SHIFT)) + +/* + * Minimum IO TLB size to bother booting with. Systems with mainly + * 64bit capable cards will only lightly use the swiotlb. If we can't + * allocate a contiguous 1MB, we're probably in trouble anyway. + */ +#define IO_TLB_MIN_SLABS ((1<<20) >> IO_TLB_SHIFT) + +enum swiotlb_force swiotlb_force; + +/* + * Used to do a quick range check in swiotlb_tbl_unmap_single and + * swiotlb_tbl_sync_single_*, to see if the memory was in fact allocated by this + * API. + */ +static phys_addr_t io_tlb_start, io_tlb_end; + +/* + * The number of IO TLB blocks (in groups of 64) between io_tlb_start and + * io_tlb_end. This is command line adjustable via setup_io_tlb_npages. + */ +static unsigned long io_tlb_nslabs; + +/* + * When the IOMMU overflows we return a fallback buffer. This sets the size. + */ +static unsigned long io_tlb_overflow = 32*1024; + +static phys_addr_t io_tlb_overflow_buffer; + +/* + * This is a free list describing the number of free entries available from + * each index + */ +static unsigned int *io_tlb_list; +static unsigned int io_tlb_index; + +/* + * Max segment that we can provide which (if pages are contingous) will + * not be bounced (unless SWIOTLB_FORCE is set). + */ +unsigned int max_segment; + +/* + * We need to save away the original address corresponding to a mapped entry + * for the sync operations. + */ +#define INVALID_PHYS_ADDR (~(phys_addr_t)0) +static phys_addr_t *io_tlb_orig_addr; + +/* + * Protect the above data structures in the map and unmap calls + */ +static DEFINE_SPINLOCK(io_tlb_lock); + +static int late_alloc; + +static int __init +setup_io_tlb_npages(char *str) +{ + if (isdigit(*str)) { + io_tlb_nslabs = simple_strtoul(str, &str, 0); + /* avoid tail segment of size < IO_TLB_SEGSIZE */ + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); + } + if (*str == ',') + ++str; + if (!strcmp(str, "force")) { + swiotlb_force = SWIOTLB_FORCE; + } else if (!strcmp(str, "noforce")) { + swiotlb_force = SWIOTLB_NO_FORCE; + io_tlb_nslabs = 1; + } + + return 0; +} +early_param("swiotlb", setup_io_tlb_npages); +/* make io_tlb_overflow tunable too? */ + +unsigned long swiotlb_nr_tbl(void) +{ + return io_tlb_nslabs; +} +EXPORT_SYMBOL_GPL(swiotlb_nr_tbl); + +unsigned int swiotlb_max_segment(void) +{ + return max_segment; +} +EXPORT_SYMBOL_GPL(swiotlb_max_segment); + +void swiotlb_set_max_segment(unsigned int val) +{ + if (swiotlb_force == SWIOTLB_FORCE) + max_segment = 1; + else + max_segment = rounddown(val, PAGE_SIZE); +} + +/* default to 64MB */ +#define IO_TLB_DEFAULT_SIZE (64UL<<20) +unsigned long swiotlb_size_or_default(void) +{ + unsigned long size; + + size = io_tlb_nslabs << IO_TLB_SHIFT; + + return size ? size : (IO_TLB_DEFAULT_SIZE); +} + +static bool no_iotlb_memory; + +void swiotlb_print_info(void) +{ + unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT; + unsigned char *vstart, *vend; + + if (no_iotlb_memory) { + pr_warn("software IO TLB: No low mem\n"); + return; + } + + vstart = phys_to_virt(io_tlb_start); + vend = phys_to_virt(io_tlb_end); + + printk(KERN_INFO "software IO TLB [mem %#010llx-%#010llx] (%luMB) mapped at [%p-%p]\n", + (unsigned long long)io_tlb_start, + (unsigned long long)io_tlb_end, + bytes >> 20, vstart, vend - 1); +} + +/* + * Early SWIOTLB allocation may be too early to allow an architecture to + * perform the desired operations. This function allows the architecture to + * call SWIOTLB when the operations are possible. It needs to be called + * before the SWIOTLB memory is used. + */ +void __init swiotlb_update_mem_attributes(void) +{ + void *vaddr; + unsigned long bytes; + + if (no_iotlb_memory || late_alloc) + return; + + vaddr = phys_to_virt(io_tlb_start); + bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT); + set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT); + memset(vaddr, 0, bytes); + + vaddr = phys_to_virt(io_tlb_overflow_buffer); + bytes = PAGE_ALIGN(io_tlb_overflow); + set_memory_decrypted((unsigned long)vaddr, bytes >> PAGE_SHIFT); + memset(vaddr, 0, bytes); +} + +int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) +{ + void *v_overflow_buffer; + unsigned long i, bytes; + + bytes = nslabs << IO_TLB_SHIFT; + + io_tlb_nslabs = nslabs; + io_tlb_start = __pa(tlb); + io_tlb_end = io_tlb_start + bytes; + + /* + * Get the overflow emergency buffer + */ + v_overflow_buffer = memblock_virt_alloc_low_nopanic( + PAGE_ALIGN(io_tlb_overflow), + PAGE_SIZE); + if (!v_overflow_buffer) + return -ENOMEM; + + io_tlb_overflow_buffer = __pa(v_overflow_buffer); + + /* + * Allocate and initialize the free list array. This array is used + * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE + * between io_tlb_start and io_tlb_end. + */ + io_tlb_list = memblock_virt_alloc( + PAGE_ALIGN(io_tlb_nslabs * sizeof(int)), + PAGE_SIZE); + io_tlb_orig_addr = memblock_virt_alloc( + PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)), + PAGE_SIZE); + for (i = 0; i < io_tlb_nslabs; i++) { + io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); + io_tlb_orig_addr[i] = INVALID_PHYS_ADDR; + } + io_tlb_index = 0; + + if (verbose) + swiotlb_print_info(); + + swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT); + return 0; +} + +/* + * Statically reserve bounce buffer space and initialize bounce buffer data + * structures for the software IO TLB used to implement the DMA API. + */ +void __init +swiotlb_init(int verbose) +{ + size_t default_size = IO_TLB_DEFAULT_SIZE; + unsigned char *vstart; + unsigned long bytes; + + if (!io_tlb_nslabs) { + io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); + } + + bytes = io_tlb_nslabs << IO_TLB_SHIFT; + + /* Get IO TLB memory from the low pages */ + vstart = memblock_virt_alloc_low_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE); + if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose)) + return; + + if (io_tlb_start) + memblock_free_early(io_tlb_start, + PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT)); + pr_warn("Cannot allocate SWIOTLB buffer"); + no_iotlb_memory = true; +} + +/* + * Systems with larger DMA zones (those that don't support ISA) can + * initialize the swiotlb later using the slab allocator if needed. + * This should be just like above, but with some error catching. + */ +int +swiotlb_late_init_with_default_size(size_t default_size) +{ + unsigned long bytes, req_nslabs = io_tlb_nslabs; + unsigned char *vstart = NULL; + unsigned int order; + int rc = 0; + + if (!io_tlb_nslabs) { + io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); + } + + /* + * Get IO TLB memory from the low pages + */ + order = get_order(io_tlb_nslabs << IO_TLB_SHIFT); + io_tlb_nslabs = SLABS_PER_PAGE << order; + bytes = io_tlb_nslabs << IO_TLB_SHIFT; + + while ((SLABS_PER_PAGE << order) > IO_TLB_MIN_SLABS) { + vstart = (void *)__get_free_pages(GFP_DMA | __GFP_NOWARN, + order); + if (vstart) + break; + order--; + } + + if (!vstart) { + io_tlb_nslabs = req_nslabs; + return -ENOMEM; + } + if (order != get_order(bytes)) { + printk(KERN_WARNING "Warning: only able to allocate %ld MB " + "for software IO TLB\n", (PAGE_SIZE << order) >> 20); + io_tlb_nslabs = SLABS_PER_PAGE << order; + } + rc = swiotlb_late_init_with_tbl(vstart, io_tlb_nslabs); + if (rc) + free_pages((unsigned long)vstart, order); + + return rc; +} + +int +swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) +{ + unsigned long i, bytes; + unsigned char *v_overflow_buffer; + + bytes = nslabs << IO_TLB_SHIFT; + + io_tlb_nslabs = nslabs; + io_tlb_start = virt_to_phys(tlb); + io_tlb_end = io_tlb_start + bytes; + + set_memory_decrypted((unsigned long)tlb, bytes >> PAGE_SHIFT); + memset(tlb, 0, bytes); + + /* + * Get the overflow emergency buffer + */ + v_overflow_buffer = (void *)__get_free_pages(GFP_DMA, + get_order(io_tlb_overflow)); + if (!v_overflow_buffer) + goto cleanup2; + + set_memory_decrypted((unsigned long)v_overflow_buffer, + io_tlb_overflow >> PAGE_SHIFT); + memset(v_overflow_buffer, 0, io_tlb_overflow); + io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer); + + /* + * Allocate and initialize the free list array. This array is used + * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE + * between io_tlb_start and io_tlb_end. + */ + io_tlb_list = (unsigned int *)__get_free_pages(GFP_KERNEL, + get_order(io_tlb_nslabs * sizeof(int))); + if (!io_tlb_list) + goto cleanup3; + + io_tlb_orig_addr = (phys_addr_t *) + __get_free_pages(GFP_KERNEL, + get_order(io_tlb_nslabs * + sizeof(phys_addr_t))); + if (!io_tlb_orig_addr) + goto cleanup4; + + for (i = 0; i < io_tlb_nslabs; i++) { + io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); + io_tlb_orig_addr[i] = INVALID_PHYS_ADDR; + } + io_tlb_index = 0; + + swiotlb_print_info(); + + late_alloc = 1; + + swiotlb_set_max_segment(io_tlb_nslabs << IO_TLB_SHIFT); + + return 0; + +cleanup4: + free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs * + sizeof(int))); + io_tlb_list = NULL; +cleanup3: + free_pages((unsigned long)v_overflow_buffer, + get_order(io_tlb_overflow)); + io_tlb_overflow_buffer = 0; +cleanup2: + io_tlb_end = 0; + io_tlb_start = 0; + io_tlb_nslabs = 0; + max_segment = 0; + return -ENOMEM; +} + +void __init swiotlb_exit(void) +{ + if (!io_tlb_orig_addr) + return; + + if (late_alloc) { + free_pages((unsigned long)phys_to_virt(io_tlb_overflow_buffer), + get_order(io_tlb_overflow)); + free_pages((unsigned long)io_tlb_orig_addr, + get_order(io_tlb_nslabs * sizeof(phys_addr_t))); + free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs * + sizeof(int))); + free_pages((unsigned long)phys_to_virt(io_tlb_start), + get_order(io_tlb_nslabs << IO_TLB_SHIFT)); + } else { + memblock_free_late(io_tlb_overflow_buffer, + PAGE_ALIGN(io_tlb_overflow)); + memblock_free_late(__pa(io_tlb_orig_addr), + PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t))); + memblock_free_late(__pa(io_tlb_list), + PAGE_ALIGN(io_tlb_nslabs * sizeof(int))); + memblock_free_late(io_tlb_start, + PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT)); + } + io_tlb_nslabs = 0; + max_segment = 0; +} + +int is_swiotlb_buffer(phys_addr_t paddr) +{ + return paddr >= io_tlb_start && paddr < io_tlb_end; +} + +/* + * Bounce: copy the swiotlb buffer back to the original dma location + */ +static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr, + size_t size, enum dma_data_direction dir) +{ + unsigned long pfn = PFN_DOWN(orig_addr); + unsigned char *vaddr = phys_to_virt(tlb_addr); + + if (PageHighMem(pfn_to_page(pfn))) { + /* The buffer does not have a mapping. Map it in and copy */ + unsigned int offset = orig_addr & ~PAGE_MASK; + char *buffer; + unsigned int sz = 0; + unsigned long flags; + + while (size) { + sz = min_t(size_t, PAGE_SIZE - offset, size); + + local_irq_save(flags); + buffer = kmap_atomic(pfn_to_page(pfn)); + if (dir == DMA_TO_DEVICE) + memcpy(vaddr, buffer + offset, sz); + else + memcpy(buffer + offset, vaddr, sz); + kunmap_atomic(buffer); + local_irq_restore(flags); + + size -= sz; + pfn++; + vaddr += sz; + offset = 0; + } + } else if (dir == DMA_TO_DEVICE) { + memcpy(vaddr, phys_to_virt(orig_addr), size); + } else { + memcpy(phys_to_virt(orig_addr), vaddr, size); + } +} + +phys_addr_t swiotlb_tbl_map_single(struct device *hwdev, + dma_addr_t tbl_dma_addr, + phys_addr_t orig_addr, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + unsigned long flags; + phys_addr_t tlb_addr; + unsigned int nslots, stride, index, wrap; + int i; + unsigned long mask; + unsigned long offset_slots; + unsigned long max_slots; + + if (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("%s is active and system is using DMA bounce buffers\n", + sme_active() ? "SME" : "SEV"); + + mask = dma_get_seg_boundary(hwdev); + + tbl_dma_addr &= mask; + + offset_slots = ALIGN(tbl_dma_addr, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; + + /* + * Carefully handle integer overflow which can occur when mask == ~0UL. + */ + max_slots = mask + 1 + ? ALIGN(mask + 1, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT + : 1UL << (BITS_PER_LONG - IO_TLB_SHIFT); + + /* + * For mappings greater than or equal to a page, we limit the stride + * (and hence alignment) to a page size. + */ + nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; + if (size >= PAGE_SIZE) + stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT)); + else + stride = 1; + + BUG_ON(!nslots); + + /* + * Find suitable number of IO TLB entries size that will fit this + * request and allocate a buffer from that IO TLB pool. + */ + spin_lock_irqsave(&io_tlb_lock, flags); + index = ALIGN(io_tlb_index, stride); + if (index >= io_tlb_nslabs) + index = 0; + wrap = index; + + do { + while (iommu_is_span_boundary(index, nslots, offset_slots, + max_slots)) { + index += stride; + if (index >= io_tlb_nslabs) + index = 0; + if (index == wrap) + goto not_found; + } + + /* + * If we find a slot that indicates we have 'nslots' number of + * contiguous buffers, we allocate the buffers from that slot + * and mark the entries as '0' indicating unavailable. + */ + if (io_tlb_list[index] >= nslots) { + int count = 0; + + for (i = index; i < (int) (index + nslots); i++) + io_tlb_list[i] = 0; + for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE - 1) && io_tlb_list[i]; i--) + io_tlb_list[i] = ++count; + tlb_addr = io_tlb_start + (index << IO_TLB_SHIFT); + + /* + * Update the indices to avoid searching in the next + * round. + */ + io_tlb_index = ((index + nslots) < io_tlb_nslabs + ? (index + nslots) : 0); + + goto found; + } + index += stride; + if (index >= io_tlb_nslabs) + index = 0; + } while (index != wrap); + +not_found: + spin_unlock_irqrestore(&io_tlb_lock, flags); + if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) + dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size); + return SWIOTLB_MAP_ERROR; +found: + spin_unlock_irqrestore(&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++) + 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_addr, size, DMA_TO_DEVICE); + + return tlb_addr; +} + +/* + * Allocates bounce buffer and returns its physical address. + */ +static phys_addr_t +map_single(struct device *hwdev, phys_addr_t phys, size_t size, + enum dma_data_direction dir, unsigned long attrs) +{ + dma_addr_t start_dma_addr; + + if (swiotlb_force == SWIOTLB_NO_FORCE) { + dev_warn_ratelimited(hwdev, "Cannot do DMA to address %pa\n", + &phys); + return SWIOTLB_MAP_ERROR; + } + + start_dma_addr = __phys_to_dma(hwdev, io_tlb_start); + return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, + dir, attrs); +} + +/* + * tlb_addr is the physical address of the bounce buffer to unmap. + */ +void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr, + size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + unsigned long flags; + int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; + int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT; + phys_addr_t orig_addr = 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_addr, size, DMA_FROM_DEVICE); + + /* + * Return the buffer to the free list by setting the corresponding + * entries to indicate the number of contiguous entries available. + * While returning the entries to the free list, we merge the entries + * with slots below and above the pool being returned. + */ + spin_lock_irqsave(&io_tlb_lock, flags); + { + count = ((index + nslots) < ALIGN(index + 1, IO_TLB_SEGSIZE) ? + io_tlb_list[index + nslots] : 0); + /* + * Step 1: return the slots to the free list, merging the + * slots with superceeding slots + */ + for (i = index + nslots - 1; i >= index; i--) { + io_tlb_list[i] = ++count; + io_tlb_orig_addr[i] = INVALID_PHYS_ADDR; + } + /* + * Step 2: merge the returned slots with the preceding slots, + * if available (non zero) + */ + for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--) + io_tlb_list[i] = ++count; + } + spin_unlock_irqrestore(&io_tlb_lock, flags); +} + +void swiotlb_tbl_sync_single(struct device *hwdev, phys_addr_t tlb_addr, + size_t size, enum dma_data_direction dir, + enum dma_sync_target target) +{ + int index = (tlb_addr - io_tlb_start) >> IO_TLB_SHIFT; + phys_addr_t orig_addr = io_tlb_orig_addr[index]; + + if (orig_addr == INVALID_PHYS_ADDR) + return; + orig_addr += (unsigned long)tlb_addr & ((1 << IO_TLB_SHIFT) - 1); + + switch (target) { + case SYNC_FOR_CPU: + if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)) + swiotlb_bounce(orig_addr, tlb_addr, + size, DMA_FROM_DEVICE); + else + BUG_ON(dir != DMA_TO_DEVICE); + break; + case SYNC_FOR_DEVICE: + if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) + swiotlb_bounce(orig_addr, tlb_addr, + size, DMA_TO_DEVICE); + else + BUG_ON(dir != DMA_FROM_DEVICE); + break; + default: + BUG(); + } +} + +static inline bool dma_coherent_ok(struct device *dev, dma_addr_t addr, + size_t size) +{ + u64 mask = DMA_BIT_MASK(32); + + if (dev && dev->coherent_dma_mask) + mask = dev->coherent_dma_mask; + return addr + size - 1 <= mask; +} + +static void * +swiotlb_alloc_buffer(struct device *dev, size_t size, dma_addr_t *dma_handle, + unsigned long attrs) +{ + phys_addr_t phys_addr; + + if (swiotlb_force == SWIOTLB_NO_FORCE) + goto out_warn; + + phys_addr = swiotlb_tbl_map_single(dev, + __phys_to_dma(dev, io_tlb_start), + 0, size, DMA_FROM_DEVICE, attrs); + if (phys_addr == SWIOTLB_MAP_ERROR) + goto out_warn; + + *dma_handle = __phys_to_dma(dev, phys_addr); + if (!dma_coherent_ok(dev, *dma_handle, size)) + goto out_unmap; + + memset(phys_to_virt(phys_addr), 0, size); + return phys_to_virt(phys_addr); + +out_unmap: + dev_warn(dev, "hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", + (unsigned long long)dev->coherent_dma_mask, + (unsigned long long)*dma_handle); + + /* + * DMA_TO_DEVICE to avoid memcpy in unmap_single. + * DMA_ATTR_SKIP_CPU_SYNC is optional. + */ + swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); +out_warn: + if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit()) { + dev_warn(dev, + "swiotlb: coherent allocation failed, size=%zu\n", + size); + dump_stack(); + } + return NULL; +} + +static bool swiotlb_free_buffer(struct device *dev, size_t size, + dma_addr_t dma_addr) +{ + phys_addr_t phys_addr = dma_to_phys(dev, dma_addr); + + WARN_ON_ONCE(irqs_disabled()); + + if (!is_swiotlb_buffer(phys_addr)) + return false; + + /* + * DMA_TO_DEVICE to avoid memcpy in swiotlb_tbl_unmap_single. + * DMA_ATTR_SKIP_CPU_SYNC is optional. + */ + swiotlb_tbl_unmap_single(dev, phys_addr, size, DMA_TO_DEVICE, + DMA_ATTR_SKIP_CPU_SYNC); + return true; +} + +static void +swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir, + int do_panic) +{ + if (swiotlb_force == SWIOTLB_NO_FORCE) + return; + + /* + * Ran out of IOMMU space for this operation. This is very bad. + * Unfortunately the drivers cannot handle this operation properly. + * unless they check for dma_mapping_error (most don't) + * When the mapping is small enough return a static buffer to limit + * the damage, or panic when the transfer is too big. + */ + dev_err_ratelimited(dev, "DMA: Out of SW-IOMMU space for %zu bytes\n", + size); + + if (size <= io_tlb_overflow || !do_panic) + return; + + if (dir == DMA_BIDIRECTIONAL) + panic("DMA: Random memory could be DMA accessed\n"); + if (dir == DMA_FROM_DEVICE) + panic("DMA: Random memory could be DMA written\n"); + if (dir == DMA_TO_DEVICE) + panic("DMA: Random memory could be DMA read\n"); +} + +/* + * Map a single buffer of the indicated size for DMA in streaming mode. The + * physical address to use is returned. + * + * Once the device is given the dma address, the device owns this memory until + * either swiotlb_unmap_page or swiotlb_dma_sync_single is performed. + */ +dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, + unsigned long offset, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + phys_addr_t map, phys = page_to_phys(page) + offset; + dma_addr_t dev_addr = phys_to_dma(dev, phys); + + BUG_ON(dir == DMA_NONE); + /* + * If the address happens to be in the device's DMA window, + * we can safely return the device addr and not worry about bounce + * buffering it. + */ + if (dma_capable(dev, dev_addr, size) && swiotlb_force != SWIOTLB_FORCE) + return dev_addr; + + trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force); + + /* Oh well, have to allocate and map a bounce buffer. */ + map = map_single(dev, phys, size, dir, attrs); + if (map == SWIOTLB_MAP_ERROR) { + swiotlb_full(dev, size, dir, 1); + return __phys_to_dma(dev, io_tlb_overflow_buffer); + } + + dev_addr = __phys_to_dma(dev, map); + + /* Ensure that the address returned is DMA'ble */ + if (dma_capable(dev, dev_addr, size)) + return dev_addr; + + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + swiotlb_tbl_unmap_single(dev, map, size, dir, attrs); + + return __phys_to_dma(dev, io_tlb_overflow_buffer); +} + +/* + * Unmap a single streaming mode DMA translation. The dma_addr and size must + * match what was provided for in a previous swiotlb_map_page call. All + * other usages are undefined. + * + * After this call, reads by the cpu to the buffer are guaranteed to see + * whatever the device wrote there. + */ +static void unmap_single(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + phys_addr_t paddr = dma_to_phys(hwdev, dev_addr); + + BUG_ON(dir == DMA_NONE); + + if (is_swiotlb_buffer(paddr)) { + swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs); + return; + } + + if (dir != DMA_FROM_DEVICE) + return; + + /* + * phys_to_virt doesn't work with hihgmem page but we could + * call dma_mark_clean() with hihgmem page here. However, we + * are fine since dma_mark_clean() is null on POWERPC. We can + * make dma_mark_clean() take a physical address if necessary. + */ + dma_mark_clean(phys_to_virt(paddr), size); +} + +void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + unsigned long attrs) +{ + unmap_single(hwdev, dev_addr, size, dir, attrs); +} + +/* + * Make physical memory consistent for a single streaming mode DMA translation + * after a transfer. + * + * If you perform a swiotlb_map_page() but wish to interrogate the buffer + * using the cpu, yet do not wish to teardown the dma mapping, you must + * call this function before doing so. At the next point you give the dma + * address back to the card, you must first perform a + * swiotlb_dma_sync_for_device, and then the device again owns the buffer + */ +static void +swiotlb_sync_single(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir, + enum dma_sync_target target) +{ + phys_addr_t paddr = dma_to_phys(hwdev, dev_addr); + + BUG_ON(dir == DMA_NONE); + + if (is_swiotlb_buffer(paddr)) { + swiotlb_tbl_sync_single(hwdev, paddr, size, dir, target); + return; + } + + if (dir != DMA_FROM_DEVICE) + return; + + dma_mark_clean(phys_to_virt(paddr), size); +} + +void +swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir) +{ + swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_CPU); +} + +void +swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, + size_t size, enum dma_data_direction dir) +{ + swiotlb_sync_single(hwdev, dev_addr, size, dir, SYNC_FOR_DEVICE); +} + +/* + * Map a set of buffers described by scatterlist in streaming mode for DMA. + * This is the scatter-gather version of the above swiotlb_map_page + * interface. Here the scatter gather list elements are each tagged with the + * appropriate dma address and length. They are obtained via + * sg_dma_{address,length}(SG). + * + * NOTE: An implementation may be able to use a smaller number of + * DMA address/length pairs than there are SG table elements. + * (for example via virtual mapping capabilities) + * The routine returns the number of addr/length pairs actually + * used, at most nents. + * + * Device ownership issues as mentioned above for swiotlb_map_page are the + * same here. + */ +int +swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems, + enum dma_data_direction dir, unsigned long attrs) +{ + struct scatterlist *sg; + int i; + + BUG_ON(dir == DMA_NONE); + + for_each_sg(sgl, sg, nelems, i) { + phys_addr_t paddr = sg_phys(sg); + dma_addr_t dev_addr = phys_to_dma(hwdev, paddr); + + if (swiotlb_force == SWIOTLB_FORCE || + !dma_capable(hwdev, dev_addr, sg->length)) { + phys_addr_t map = map_single(hwdev, sg_phys(sg), + sg->length, dir, attrs); + if (map == SWIOTLB_MAP_ERROR) { + /* Don't panic here, we expect map_sg users + to do proper error handling. */ + swiotlb_full(hwdev, sg->length, dir, 0); + attrs |= DMA_ATTR_SKIP_CPU_SYNC; + swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir, + attrs); + sg_dma_len(sgl) = 0; + return 0; + } + sg->dma_address = __phys_to_dma(hwdev, map); + } else + sg->dma_address = dev_addr; + sg_dma_len(sg) = sg->length; + } + return nelems; +} + +/* + * Unmap a set of streaming mode DMA translations. Again, cpu read rules + * concerning calls here are the same as for swiotlb_unmap_page() above. + */ +void +swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + unsigned long attrs) +{ + struct scatterlist *sg; + int i; + + BUG_ON(dir == DMA_NONE); + + for_each_sg(sgl, sg, nelems, i) + unmap_single(hwdev, sg->dma_address, sg_dma_len(sg), dir, + attrs); +} + +/* + * Make physical memory consistent for a set of streaming mode DMA translations + * after a transfer. + * + * The same as swiotlb_sync_single_* but for a scatter-gather list, same rules + * and usage. + */ +static void +swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl, + int nelems, enum dma_data_direction dir, + enum dma_sync_target target) +{ + struct scatterlist *sg; + int i; + + for_each_sg(sgl, sg, nelems, i) + swiotlb_sync_single(hwdev, sg->dma_address, + sg_dma_len(sg), dir, target); +} + +void +swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir) +{ + swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_CPU); +} + +void +swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, + int nelems, enum dma_data_direction dir) +{ + swiotlb_sync_sg(hwdev, sg, nelems, dir, SYNC_FOR_DEVICE); +} + +int +swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr) +{ + return (dma_addr == __phys_to_dma(hwdev, io_tlb_overflow_buffer)); +} + +/* + * Return whether the given device DMA address mask can be supported + * properly. For example, if your device can only drive the low 24-bits + * during bus mastering, then you would pass 0x00ffffff as the mask to + * this function. + */ +int +swiotlb_dma_supported(struct device *hwdev, u64 mask) +{ + return __phys_to_dma(hwdev, io_tlb_end - 1) <= mask; +} + +void *swiotlb_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, + gfp_t gfp, unsigned long attrs) +{ + void *vaddr; + + /* temporary workaround: */ + if (gfp & __GFP_NOWARN) + attrs |= DMA_ATTR_NO_WARN; + + /* + * Don't print a warning when the first allocation attempt fails. + * swiotlb_alloc_coherent() will print a warning when the DMA memory + * allocation ultimately failed. + */ + gfp |= __GFP_NOWARN; + + vaddr = dma_direct_alloc(dev, size, dma_handle, gfp, attrs); + if (!vaddr) + vaddr = swiotlb_alloc_buffer(dev, size, dma_handle, attrs); + return vaddr; +} + +void swiotlb_free(struct device *dev, size_t size, void *vaddr, + dma_addr_t dma_addr, unsigned long attrs) +{ + if (!swiotlb_free_buffer(dev, size, dma_addr)) + dma_direct_free(dev, size, vaddr, dma_addr, attrs); +} + +const struct dma_map_ops swiotlb_dma_ops = { + .mapping_error = swiotlb_dma_mapping_error, + .alloc = swiotlb_alloc, + .free = swiotlb_free, + .sync_single_for_cpu = swiotlb_sync_single_for_cpu, + .sync_single_for_device = swiotlb_sync_single_for_device, + .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu, + .sync_sg_for_device = swiotlb_sync_sg_for_device, + .map_sg = swiotlb_map_sg_attrs, + .unmap_sg = swiotlb_unmap_sg_attrs, + .map_page = swiotlb_map_page, + .unmap_page = swiotlb_unmap_page, + .dma_supported = dma_direct_supported, +}; |