litmus-rt.git - The LITMUS^RT kernel.

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Diffstat (limited to 'include/linux/usb/gadget.h')

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/* * 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. */ #include <linux/cache.h> #include <linux/dma-mapping.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/spinlock.h> #include <linux/string.h> #include <linux/types.h> #include <linux/ctype.h> #include <asm/io.h> #include <asm/dma.h> #include <asm/scatterlist.h> #include <linux/init.h> #include <linux/bootmem.h> #define OFFSET(val,align) ((unsigned long) \ ( (val) & ( (align) - 1))) #define SG_ENT_VIRT_ADDRESS(sg) (page_address((sg)->page) + (sg)->offset) #define SG_ENT_PHYS_ADDRESS(sg) virt_to_bus(SG_ENT_VIRT_ADDRESS(sg)) /* * Maximum allowable number of contiguous slabs to map, * must be a power of 2. What is the appropriate value ? * The complexity of {map,unmap}_single is linearly dependent on this value. */ #define IO_TLB_SEGSIZE 128 /* * log of the size of each IO TLB slab. The number of slabs is command line * controllable. */ #define IO_TLB_SHIFT 11 #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) /* * Enumeration for sync targets */ enum dma_sync_target { SYNC_FOR_CPU = 0, SYNC_FOR_DEVICE = 1, }; int swiotlb_force; /* * Used to do a quick range check in swiotlb_unmap_single and * swiotlb_sync_single_*, to see if the memory was in fact allocated by this * API. */ static char *io_tlb_start, *io_tlb_end; /* * The number of IO TLB blocks (in groups of 64) betweeen 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; void *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; /* * We need to save away the original address corresponding to a mapped entry * for the sync operations. */ static unsigned char **io_tlb_orig_addr; /* * Protect the above data structures in the map and unmap calls */ static DEFINE_SPINLOCK(io_tlb_lock); 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 = 1; return 1; } __setup("swiotlb=", setup_io_tlb_npages); /* make io_tlb_overflow tunable too? */ /* * 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_with_default_size(size_t default_size) { unsigned long i, 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 */ io_tlb_start = alloc_bootmem_low_pages(bytes); if (!io_tlb_start) panic("Cannot allocate SWIOTLB buffer"); 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. */ io_tlb_list = alloc_bootmem(io_tlb_nslabs * sizeof(int)); for (i = 0; i < io_tlb_nslabs; i++) io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); io_tlb_index = 0; io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(char *)); /* * Get the overflow emergency buffer */ io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow); if (!io_tlb_overflow_buffer) panic("Cannot allocate SWIOTLB overflow buffer!\n"); printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n", virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end)); } void __init swiotlb_init(void) { swiotlb_init_with_default_size(64 * (1<<20)); /* default to 64MB */ } /* * 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 i, bytes, req_nslabs = io_tlb_nslabs; unsigned int order; 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) { io_tlb_start = (char *)__get_free_pages(GFP_DMA | __GFP_NOWARN, order); if (io_tlb_start) break; order--; } if (!io_tlb_start) goto cleanup1; 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; bytes = io_tlb_nslabs << IO_TLB_SHIFT; } io_tlb_end = io_tlb_start + bytes; memset(io_tlb_start, 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 cleanup2; for (i = 0; i < io_tlb_nslabs; i++) io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE); io_tlb_index = 0; io_tlb_orig_addr = (unsigned char **)__get_free_pages(GFP_KERNEL, get_order(io_tlb_nslabs * sizeof(char *))); if (!io_tlb_orig_addr) goto cleanup3; memset(io_tlb_orig_addr, 0, io_tlb_nslabs * sizeof(char *)); /* * Get the overflow emergency buffer */ io_tlb_overflow_buffer = (void *)__get_free_pages(GFP_DMA, get_order(io_tlb_overflow)); if (!io_tlb_overflow_buffer) goto cleanup4; printk(KERN_INFO "Placing %luMB software IO TLB between 0x%lx - " "0x%lx\n", bytes >> 20, virt_to_bus(io_tlb_start), virt_to_bus(io_tlb_end)); return 0; cleanup4: free_pages((unsigned long)io_tlb_orig_addr, get_order(io_tlb_nslabs * sizeof(char *))); io_tlb_orig_addr = NULL; cleanup3: free_pages((unsigned long)io_tlb_list, get_order(io_tlb_nslabs * sizeof(int))); io_tlb_list = NULL; cleanup2: io_tlb_end = NULL; free_pages((unsigned long)io_tlb_start, order); io_tlb_start = NULL; cleanup1: io_tlb_nslabs = req_nslabs; return -ENOMEM; } static int address_needs_mapping(struct device *hwdev, dma_addr_t addr) { dma_addr_t mask = 0xffffffff; /* If the device has a mask, use it, otherwise default to 32 bits */ if (hwdev && hwdev->dma_mask) mask = *hwdev->dma_mask; return (addr & ~mask) != 0; } /* * Allocates bounce buffer and returns its kernel virtual address. */ static void * map_single(struct device *hwdev, char *buffer, size_t size, int dir) { unsigned long flags; char *dma_addr; unsigned int nslots, stride, index, wrap; int i; /* * For mappings greater than 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); { wrap = index = ALIGN(io_tlb_index, stride); if (index >= io_tlb_nslabs) wrap = index = 0; do { /* * 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; dma_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); spin_unlock_irqrestore(&io_tlb_lock, flags); return NULL; } 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. */ io_tlb_orig_addr[index] = buffer; if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) memcpy(dma_addr, buffer, size); return dma_addr; } /* * dma_addr is the kernel virtual address of the bounce buffer to unmap. */ static void unmap_single(struct device *hwdev, char *dma_addr, size_t size, int dir) { unsigned long flags; int i, count, nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT; int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT; char *buffer = io_tlb_orig_addr[index]; /* * First, sync the memory before unmapping the entry */ if (buffer && ((dir == DMA_FROM_DEVICE) || (dir == DMA_BIDIRECTIONAL))) /* * bounce... copy the data back into the original buffer * and * delete the bounce buffer. */ memcpy(buffer, dma_addr, size); /* * Return the buffer to the free list by setting the corresponding * entries to indicate the number of contigous 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; /* * 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); } static void sync_single(struct device *hwdev, char *dma_addr, size_t size, int dir, int target) { int index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT; char *buffer = io_tlb_orig_addr[index]; switch (target) { case SYNC_FOR_CPU: if (likely(dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)) memcpy(buffer, dma_addr, size); else BUG_ON(dir != DMA_TO_DEVICE); break; case SYNC_FOR_DEVICE: if (likely(dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL)) memcpy(dma_addr, buffer, size); else BUG_ON(dir != DMA_FROM_DEVICE); break; default: BUG(); } } void * swiotlb_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t flags) { dma_addr_t dev_addr; void *ret; int order = get_order(size); /* * XXX fix me: the DMA API should pass us an explicit DMA mask * instead, or use ZONE_DMA32 (ia64 overloads ZONE_DMA to be a ~32 * bit range instead of a 16MB one). */ flags |= GFP_DMA; ret = (void *)__get_free_pages(flags, order); if (ret && address_needs_mapping(hwdev, virt_to_bus(ret))) { /* * The allocated memory isn't reachable by the device. * Fall back on swiotlb_map_single(). */ free_pages((unsigned long) ret, order); ret = NULL; } if (!ret) { /* * We are either out of memory or the device can't DMA * to GFP_DMA memory; fall back on * swiotlb_map_single(), which will grab memory from * the lowest available address range. */ dma_addr_t handle; handle = swiotlb_map_single(NULL, NULL, size, DMA_FROM_DEVICE); if (swiotlb_dma_mapping_error(handle)) return NULL; ret = bus_to_virt(handle); } memset(ret, 0, size); dev_addr = virt_to_bus(ret); /* Confirm address can be DMA'd by device */ if (address_needs_mapping(hwdev, dev_addr)) { printk("hwdev DMA mask = 0x%016Lx, dev_addr = 0x%016Lx\n", (unsigned long long)*hwdev->dma_mask,


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