diff options
Diffstat (limited to 'kernel/dma/swiotlb.c')
| -rw-r--r-- | kernel/dma/swiotlb.c | 774 |
1 files changed, 774 insertions, 0 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c new file mode 100644 index 000000000..d897d1613 --- /dev/null +++ b/kernel/dma/swiotlb.c @@ -0,0 +1,774 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 + */ + +#define pr_fmt(fmt) "software IO TLB: " fmt + +#include <linux/cache.h> +#include <linux/dma-direct.h> +#include <linux/dma-map-ops.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> +#ifdef CONFIG_DEBUG_FS +#include <linux/debugfs.h> +#endif + +#include <asm/io.h> +#include <asm/dma.h> + +#include <linux/init.h> +#include <linux/memblock.h> +#include <linux/iommu-helper.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/swiotlb.h> + +#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. + */ +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; + +/* + * The number of used IO TLB block + */ +static unsigned long io_tlb_used; + +/* + * 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). + */ +static 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); + +static bool no_iotlb_memory; + +unsigned long swiotlb_nr_tbl(void) +{ + return unlikely(no_iotlb_memory) ? 0 : io_tlb_nslabs; +} +EXPORT_SYMBOL_GPL(swiotlb_nr_tbl); + +unsigned int swiotlb_max_segment(void) +{ + return unlikely(no_iotlb_memory) ? 0 : 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); +} + +void swiotlb_print_info(void) +{ + unsigned long bytes = io_tlb_nslabs << IO_TLB_SHIFT; + + if (no_iotlb_memory) { + pr_warn("No low mem\n"); + return; + } + + pr_info("mapped [mem %pa-%pa] (%luMB)\n", &io_tlb_start, &io_tlb_end, + bytes >> 20); +} + +static inline unsigned long io_tlb_offset(unsigned long val) +{ + return val & (IO_TLB_SEGSIZE - 1); +} + +static inline unsigned long nr_slots(u64 val) +{ + return DIV_ROUND_UP(val, IO_TLB_SIZE); +} + +/* + * 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); +} + +int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) +{ + unsigned long i, bytes; + size_t alloc_size; + + bytes = nslabs << IO_TLB_SHIFT; + + io_tlb_nslabs = nslabs; + io_tlb_start = __pa(tlb); + io_tlb_end = io_tlb_start + bytes; + + /* + * 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. + */ + alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(int)); + io_tlb_list = memblock_alloc(alloc_size, PAGE_SIZE); + if (!io_tlb_list) + panic("%s: Failed to allocate %zu bytes align=0x%lx\n", + __func__, alloc_size, PAGE_SIZE); + + alloc_size = PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)); + io_tlb_orig_addr = memblock_alloc(alloc_size, PAGE_SIZE); + if (!io_tlb_orig_addr) + panic("%s: Failed to allocate %zu bytes align=0x%lx\n", + __func__, alloc_size, PAGE_SIZE); + + for (i = 0; i < io_tlb_nslabs; i++) { + io_tlb_list[i] = IO_TLB_SEGSIZE - io_tlb_offset(i); + io_tlb_orig_addr[i] = INVALID_PHYS_ADDR; + } + io_tlb_index = 0; + no_iotlb_memory = false; + + 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_alloc_low(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)); + io_tlb_start = 0; + } + pr_warn("Cannot allocate 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)) { + pr_warn("only able to allocate %ld MB\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; +} + +static void swiotlb_cleanup(void) +{ + io_tlb_end = 0; + io_tlb_start = 0; + io_tlb_nslabs = 0; + max_segment = 0; +} + +int +swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) +{ + unsigned long i, bytes; + + 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); + + /* + * 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 - io_tlb_offset(i); + io_tlb_orig_addr[i] = INVALID_PHYS_ADDR; + } + io_tlb_index = 0; + no_iotlb_memory = false; + + 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: + swiotlb_cleanup(); + return -ENOMEM; +} + +void __init swiotlb_exit(void) +{ + if (!io_tlb_orig_addr) + return; + + if (late_alloc) { + 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(__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)); + } + swiotlb_cleanup(); +} + +/* + * Bounce: copy the swiotlb buffer from or 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); + } +} + +static inline phys_addr_t slot_addr(phys_addr_t start, phys_addr_t idx) +{ + return start + (idx << IO_TLB_SHIFT); +} + +/* + * Return the offset into a iotlb slot required to keep the device happy. + */ +static unsigned int swiotlb_align_offset(struct device *dev, u64 addr) +{ + return addr & dma_get_min_align_mask(dev) & (IO_TLB_SIZE - 1); +} + +/* + * Carefully handle integer overflow which can occur when boundary_mask == ~0UL. + */ +static inline unsigned long get_max_slots(unsigned long boundary_mask) +{ + if (boundary_mask == ~0UL) + return 1UL << (BITS_PER_LONG - IO_TLB_SHIFT); + return nr_slots(boundary_mask + 1); +} + +static unsigned int wrap_index(unsigned int index) +{ + if (index >= io_tlb_nslabs) + return 0; + return index; +} + +/* + * Find a suitable number of IO TLB entries size that will fit this request and + * allocate a buffer from that IO TLB pool. + */ +static int find_slots(struct device *dev, phys_addr_t orig_addr, + size_t alloc_size) +{ + unsigned long boundary_mask = dma_get_seg_boundary(dev); + dma_addr_t tbl_dma_addr = + phys_to_dma_unencrypted(dev, io_tlb_start) & boundary_mask; + unsigned long max_slots = get_max_slots(boundary_mask); + unsigned int iotlb_align_mask = + dma_get_min_align_mask(dev) & ~(IO_TLB_SIZE - 1); + unsigned int nslots = nr_slots(alloc_size), stride; + unsigned int index, wrap, count = 0, i; + unsigned long flags; + + BUG_ON(!nslots); + + /* + * For mappings with an alignment requirement don't bother looping to + * unaligned slots once we found an aligned one. For allocations of + * PAGE_SIZE or larger only look for page aligned allocations. + */ + stride = (iotlb_align_mask >> IO_TLB_SHIFT) + 1; + if (alloc_size >= PAGE_SIZE) + stride = max(stride, stride << (PAGE_SHIFT - IO_TLB_SHIFT)); + + spin_lock_irqsave(&io_tlb_lock, flags); + if (unlikely(nslots > io_tlb_nslabs - io_tlb_used)) + goto not_found; + + index = wrap = wrap_index(ALIGN(io_tlb_index, stride)); + do { + if ((slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != + (orig_addr & iotlb_align_mask)) { + index = wrap_index(index + 1); + continue; + } + + /* + * 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 (!iommu_is_span_boundary(index, nslots, + nr_slots(tbl_dma_addr), + max_slots)) { + if (io_tlb_list[index] >= nslots) + goto found; + } + index = wrap_index(index + stride); + } while (index != wrap); + +not_found: + spin_unlock_irqrestore(&io_tlb_lock, flags); + return -1; + +found: + for (i = index; i < index + nslots; i++) + io_tlb_list[i] = 0; + for (i = index - 1; + io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && + io_tlb_list[i]; i--) + io_tlb_list[i] = ++count; + + /* + * Update the indices to avoid searching in the next round. + */ + if (index + nslots < io_tlb_nslabs) + io_tlb_index = index + nslots; + else + io_tlb_index = 0; + io_tlb_used += nslots; + + spin_unlock_irqrestore(&io_tlb_lock, flags); + return index; +} + +phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, + size_t mapping_size, size_t alloc_size, + enum dma_data_direction dir, unsigned long attrs) +{ + unsigned int offset = swiotlb_align_offset(dev, orig_addr); + unsigned int i; + int index; + phys_addr_t tlb_addr; + + 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("Memory encryption is active and system is using DMA bounce buffers\n"); + + if (mapping_size > alloc_size) { + dev_warn_once(dev, "Invalid sizes (mapping: %zd bytes, alloc: %zd bytes)", + mapping_size, alloc_size); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + + index = find_slots(dev, orig_addr, alloc_size + offset); + if (index == -1) { + if (!(attrs & DMA_ATTR_NO_WARN)) + dev_warn_ratelimited(dev, + "swiotlb buffer is full (sz: %zd bytes), total %lu (slots), used %lu (slots)\n", + alloc_size, io_tlb_nslabs, io_tlb_used); + return (phys_addr_t)DMA_MAPPING_ERROR; + } + + /* + * 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 < nr_slots(alloc_size + offset); i++) + io_tlb_orig_addr[index + i] = slot_addr(orig_addr, i); + + tlb_addr = slot_addr(io_tlb_start, index) + offset; + /* + * When dir == DMA_FROM_DEVICE we could omit the copy from the orig + * to the tlb buffer, if we knew for sure the device will + * overwirte the entire current content. But we don't. Thus + * unconditional bounce may prevent leaking swiotlb content (i.e. + * kernel memory) to user-space. + */ + swiotlb_bounce(orig_addr, 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 device *hwdev, phys_addr_t tlb_addr, + size_t mapping_size, size_t alloc_size, + enum dma_data_direction dir, unsigned long attrs) +{ + unsigned long flags; + unsigned int offset = swiotlb_align_offset(hwdev, tlb_addr); + int i, count, nslots = nr_slots(alloc_size + offset); + int index = (tlb_addr - offset - 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, mapping_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); + if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE)) + count = io_tlb_list[index + nslots]; + else + count = 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; + io_tlb_offset(i) != IO_TLB_SEGSIZE - 1 && io_tlb_list[i]; + i--) + io_tlb_list[i] = ++count; + io_tlb_used -= nslots; + 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 += (tlb_addr & (IO_TLB_SIZE - 1)) - + swiotlb_align_offset(hwdev, orig_addr); + + 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(); + } +} + +/* + * Create a swiotlb mapping for the buffer at @paddr, and in case of DMAing + * to the device copy the data into it as well. + */ +dma_addr_t swiotlb_map(struct device *dev, phys_addr_t paddr, size_t size, + enum dma_data_direction dir, unsigned long attrs) +{ + phys_addr_t swiotlb_addr; + dma_addr_t dma_addr; + + trace_swiotlb_bounced(dev, phys_to_dma(dev, paddr), size, + swiotlb_force); + + swiotlb_addr = swiotlb_tbl_map_single(dev, paddr, size, size, dir, + attrs); + if (swiotlb_addr == (phys_addr_t)DMA_MAPPING_ERROR) + return DMA_MAPPING_ERROR; + + /* Ensure that the address returned is DMA'ble */ + dma_addr = phys_to_dma_unencrypted(dev, swiotlb_addr); + if (unlikely(!dma_capable(dev, dma_addr, size, true))) { + swiotlb_tbl_unmap_single(dev, swiotlb_addr, size, size, dir, + attrs | DMA_ATTR_SKIP_CPU_SYNC); + dev_WARN_ONCE(dev, 1, + "swiotlb addr %pad+%zu overflow (mask %llx, bus limit %llx).\n", + &dma_addr, size, *dev->dma_mask, dev->bus_dma_limit); + return DMA_MAPPING_ERROR; + } + + if (!dev_is_dma_coherent(dev) && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + arch_sync_dma_for_device(swiotlb_addr, size, dir); + return dma_addr; +} + +size_t swiotlb_max_mapping_size(struct device *dev) +{ + int min_align_mask = dma_get_min_align_mask(dev); + int min_align = 0; + + /* + * swiotlb_find_slots() skips slots according to + * min align mask. This affects max mapping size. + * Take it into acount here. + */ + if (min_align_mask) + min_align = roundup(min_align_mask, IO_TLB_SIZE); + + return ((size_t)IO_TLB_SIZE) * IO_TLB_SEGSIZE - min_align; +} + +bool is_swiotlb_active(void) +{ + /* + * When SWIOTLB is initialized, even if io_tlb_start points to physical + * address zero, io_tlb_end surely doesn't. + */ + return io_tlb_end != 0; +} + +#ifdef CONFIG_DEBUG_FS + +static int __init swiotlb_create_debugfs(void) +{ + struct dentry *root; + + root = debugfs_create_dir("swiotlb", NULL); + debugfs_create_ulong("io_tlb_nslabs", 0400, root, &io_tlb_nslabs); + debugfs_create_ulong("io_tlb_used", 0400, root, &io_tlb_used); + return 0; +} + +late_initcall(swiotlb_create_debugfs); + +#endif |