diff options
Diffstat (limited to 'arch/ia64/lib/swiotlb.c')
| -rw-r--r-- | arch/ia64/lib/swiotlb.c | 658 |
1 files changed, 658 insertions, 0 deletions
diff --git a/arch/ia64/lib/swiotlb.c b/arch/ia64/lib/swiotlb.c new file mode 100644 index 00000000000..ab7b3ad99a7 --- /dev/null +++ b/arch/ia64/lib/swiotlb.c @@ -0,0 +1,658 @@ +/* + * Dynamic DMA mapping support. + * + * This implementation is for IA-64 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. + */ + +#include <linux/cache.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/ctype.h> + +#include <asm/io.h> +#include <asm/pci.h> +#include <asm/dma.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_phys(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 + +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) << + (PAGE_SHIFT - IO_TLB_SHIFT); + /* 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 PCI DMA API. + */ +void +swiotlb_init_with_default_size (size_t default_size) +{ + unsigned long i; + + if (!io_tlb_nslabs) { + io_tlb_nslabs = (default_size >> PAGE_SHIFT); + io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); + } + + /* + * Get IO TLB memory from the low pages + */ + io_tlb_start = alloc_bootmem_low_pages(io_tlb_nslabs * + (1 << IO_TLB_SHIFT)); + if (!io_tlb_start) + panic("Cannot allocate SWIOTLB buffer"); + io_tlb_end = io_tlb_start + io_tlb_nslabs * (1 << IO_TLB_SHIFT); + + /* + * 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); + printk(KERN_INFO "Placing software IO TLB between 0x%lx - 0x%lx\n", + virt_to_phys(io_tlb_start), virt_to_phys(io_tlb_end)); +} + +void +swiotlb_init (void) +{ + swiotlb_init_with_default_size(64 * (1<<20)); /* default to 64MB */ +} + +static inline 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; + + if (!nslots) + BUG(); + + /* + * 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 index = (dma_addr - io_tlb_start) >> IO_TLB_SHIFT; + char *buffer = io_tlb_orig_addr[index]; + + /* + * bounce... copy the data back into/from the original buffer + * XXX How do you handle DMA_BIDIRECTIONAL here ? + */ + if (dir == DMA_FROM_DEVICE) + memcpy(buffer, dma_addr, size); + else if (dir == DMA_TO_DEVICE) + memcpy(dma_addr, buffer, size); + else + BUG(); +} + +void * +swiotlb_alloc_coherent(struct device *hwdev, size_t size, + dma_addr_t *dma_handle, int flags) +{ + unsigned long 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_phys(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 (dma_mapping_error(handle)) + return NULL; + + ret = phys_to_virt(handle); + } + + memset(ret, 0, size); + dev_addr = virt_to_phys(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, dev_addr); + panic("swiotlb_alloc_coherent: allocated memory is out of " + "range for device"); + } + *dma_handle = dev_addr; + return ret; +} + +void +swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr, + dma_addr_t dma_handle) +{ + if (!(vaddr >= (void *)io_tlb_start + && vaddr < (void *)io_tlb_end)) + free_pages((unsigned long) vaddr, get_order(size)); + else + /* DMA_TO_DEVICE to avoid memcpy in unmap_single */ + swiotlb_unmap_single (hwdev, dma_handle, size, DMA_TO_DEVICE); +} + +static void +swiotlb_full(struct device *dev, size_t size, int dir, int do_panic) +{ + /* + * Ran out of IOMMU space for this operation. This is very bad. + * Unfortunately the drivers cannot handle this operation properly. + * unless they check for pci_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. + */ + printk(KERN_ERR "PCI-DMA: Out of SW-IOMMU space for %lu bytes at " + "device %s\n", size, dev ? dev->bus_id : "?"); + + if (size > io_tlb_overflow && do_panic) { + if (dir == PCI_DMA_FROMDEVICE || dir == PCI_DMA_BIDIRECTIONAL) + panic("PCI-DMA: Memory would be corrupted\n"); + if (dir == PCI_DMA_TODEVICE || dir == PCI_DMA_BIDIRECTIONAL) + panic("PCI-DMA: Random memory would be DMAed\n"); + } +} + +/* + * Map a single buffer of the indicated size for DMA in streaming mode. The + * PCI address to use is returned. + * + * Once the device is given the dma address, the device owns this memory until + * either swiotlb_unmap_single or swiotlb_dma_sync_single is performed. + */ +dma_addr_t +swiotlb_map_single(struct device *hwdev, void *ptr, size_t size, int dir) +{ + unsigned long dev_addr = virt_to_phys(ptr); + void *map; + + if (dir == DMA_NONE) + BUG(); + /* + * If the pointer passed in happens to be in the device's DMA window, + * we can safely return the device addr and not worry about bounce + * buffering it. + */ + if (!address_needs_mapping(hwdev, dev_addr) && !swiotlb_force) + return dev_addr; + + /* + * Oh well, have to allocate and map a bounce buffer. + */ + map = map_single(hwdev, ptr, size, dir); + if (!map) { + swiotlb_full(hwdev, size, dir, 1); + map = io_tlb_overflow_buffer; + } + + dev_addr = virt_to_phys(map); + + /* + * Ensure that the address returned is DMA'ble + */ + if (address_needs_mapping(hwdev, dev_addr)) + panic("map_single: bounce buffer is not DMA'ble"); + + return dev_addr; +} + +/* + * Since DMA is i-cache coherent, any (complete) pages that were written via + * DMA can be marked as "clean" so that lazy_mmu_prot_update() doesn't have to + * flush them when they get mapped into an executable vm-area. + */ +static void +mark_clean(void *addr, size_t size) +{ + unsigned long pg_addr, end; + + pg_addr = PAGE_ALIGN((unsigned long) addr); + end = (unsigned long) addr + size; + while (pg_addr + PAGE_SIZE <= end) { + struct page *page = virt_to_page(pg_addr); + set_bit(PG_arch_1, &page->flags); + pg_addr += PAGE_SIZE; + } +} + +/* + * Unmap a single streaming mode DMA translation. The dma_addr and size must + * match what was provided for in a previous swiotlb_map_single 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. + */ +void +swiotlb_unmap_single(struct device *hwdev, dma_addr_t dev_addr, size_t size, + int dir) +{ + char *dma_addr = phys_to_virt(dev_addr); + + if (dir == DMA_NONE) + BUG(); + if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end) + unmap_single(hwdev, dma_addr, size, dir); + else if (dir == DMA_FROM_DEVICE) + mark_clean(dma_addr, size); +} + +/* + * Make physical memory consistent for a single streaming mode DMA translation + * after a transfer. + * + * If you perform a swiotlb_map_single() but wish to interrogate the buffer + * using the cpu, yet do not wish to teardown the PCI dma mapping, you must + * call this function before doing so. At the next point you give the PCI dma + * address back to the card, you must first perform a + * swiotlb_dma_sync_for_device, and then the device again owns the buffer + */ +void +swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr, + size_t size, int dir) +{ + char *dma_addr = phys_to_virt(dev_addr); + + if (dir == DMA_NONE) + BUG(); + if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end) + sync_single(hwdev, dma_addr, size, dir); + else if (dir == DMA_FROM_DEVICE) + mark_clean(dma_addr, size); +} + +void +swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr, + size_t size, int dir) +{ + char *dma_addr = phys_to_virt(dev_addr); + + if (dir == DMA_NONE) + BUG(); + if (dma_addr >= io_tlb_start && dma_addr < io_tlb_end) + sync_single(hwdev, dma_addr, size, dir); + else if (dir == DMA_FROM_DEVICE) + mark_clean(dma_addr, size); +} + +/* + * Map a set of buffers described by scatterlist in streaming mode for DMA. + * This is the scatter-gather version of the above swiotlb_map_single + * 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_single are the + * same here. + */ +int +swiotlb_map_sg(struct device *hwdev, struct scatterlist *sg, int nelems, + int dir) +{ + void *addr; + unsigned long dev_addr; + int i; + + if (dir == DMA_NONE) + BUG(); + + for (i = 0; i < nelems; i++, sg++) { + addr = SG_ENT_VIRT_ADDRESS(sg); + dev_addr = virt_to_phys(addr); + if (swiotlb_force || address_needs_mapping(hwdev, dev_addr)) { + sg->dma_address = (dma_addr_t) virt_to_phys(map_single(hwdev, addr, sg->length, dir)); + if (!sg->dma_address) { + /* Don't panic here, we expect map_sg users + to do proper error handling. */ + swiotlb_full(hwdev, sg->length, dir, 0); + swiotlb_unmap_sg(hwdev, sg - i, i, dir); + sg[0].dma_length = 0; + return 0; + } + } else + sg->dma_address = dev_addr; + sg->dma_length = 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_single() above. + */ +void +swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sg, int nelems, + int dir) +{ + int i; + + if (dir == DMA_NONE) + BUG(); + + for (i = 0; i < nelems; i++, sg++) + if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg)) + unmap_single(hwdev, (void *) phys_to_virt(sg->dma_address), sg->dma_length, dir); + else if (dir == DMA_FROM_DEVICE) + mark_clean(SG_ENT_VIRT_ADDRESS(sg), sg->dma_length); +} + +/* + * 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. + */ +void +swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg, + int nelems, int dir) +{ + int i; + + if (dir == DMA_NONE) + BUG(); + + for (i = 0; i < nelems; i++, sg++) + if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg)) + sync_single(hwdev, (void *) sg->dma_address, + sg->dma_length, dir); +} + +void +swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg, + int nelems, int dir) +{ + int i; + + if (dir == DMA_NONE) + BUG(); + + for (i = 0; i < nelems; i++, sg++) + if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg)) + sync_single(hwdev, (void *) sg->dma_address, + sg->dma_length, dir); +} + +int +swiotlb_dma_mapping_error(dma_addr_t dma_addr) +{ + return (dma_addr == virt_to_phys(io_tlb_overflow_buffer)); +} + +/* + * Return whether the given PCI device DMA address mask can be supported + * properly. For example, if your device can only drive the low 24-bits + * during PCI bus mastering, then you would pass 0x00ffffff as the mask to + * this function. + */ +int +swiotlb_dma_supported (struct device *hwdev, u64 mask) +{ + return (virt_to_phys (io_tlb_end) - 1) <= mask; +} + +EXPORT_SYMBOL(swiotlb_init); +EXPORT_SYMBOL(swiotlb_map_single); +EXPORT_SYMBOL(swiotlb_unmap_single); +EXPORT_SYMBOL(swiotlb_map_sg); +EXPORT_SYMBOL(swiotlb_unmap_sg); +EXPORT_SYMBOL(swiotlb_sync_single_for_cpu); +EXPORT_SYMBOL(swiotlb_sync_single_for_device); +EXPORT_SYMBOL(swiotlb_sync_sg_for_cpu); +EXPORT_SYMBOL(swiotlb_sync_sg_for_device); +EXPORT_SYMBOL(swiotlb_dma_mapping_error); +EXPORT_SYMBOL(swiotlb_alloc_coherent); +EXPORT_SYMBOL(swiotlb_free_coherent); +EXPORT_SYMBOL(swiotlb_dma_supported); |