| /* |
| * arch/arm/common/dmabounce.c |
| * |
| * Special dma_{map/unmap/dma_sync}_* routines for systems that have |
| * limited DMA windows. These functions utilize bounce buffers to |
| * copy data to/from buffers located outside the DMA region. This |
| * only works for systems in which DMA memory is at the bottom of |
| * RAM, the remainder of memory is at the top and the DMA memory |
| * can be marked as ZONE_DMA. Anything beyond that such as discontiguous |
| * DMA windows will require custom implementations that reserve memory |
| * areas at early bootup. |
| * |
| * Original version by Brad Parker (brad@heeltoe.com) |
| * Re-written by Christopher Hoover <ch@murgatroid.com> |
| * Made generic by Deepak Saxena <dsaxena@plexity.net> |
| * |
| * Copyright (C) 2002 Hewlett Packard Company. |
| * Copyright (C) 2004 MontaVista Software, Inc. |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * version 2 as published by the Free Software Foundation. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/page-flags.h> |
| #include <linux/device.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/dmapool.h> |
| #include <linux/list.h> |
| #include <linux/scatterlist.h> |
| |
| #include <asm/cacheflush.h> |
| |
| #undef STATS |
| |
| #ifdef STATS |
| #define DO_STATS(X) do { X ; } while (0) |
| #else |
| #define DO_STATS(X) do { } while (0) |
| #endif |
| |
| /* ************************************************** */ |
| |
| struct safe_buffer { |
| struct list_head node; |
| |
| /* original request */ |
| void *ptr; |
| size_t size; |
| int direction; |
| |
| /* safe buffer info */ |
| struct dmabounce_pool *pool; |
| void *safe; |
| dma_addr_t safe_dma_addr; |
| }; |
| |
| struct dmabounce_pool { |
| unsigned long size; |
| struct dma_pool *pool; |
| #ifdef STATS |
| unsigned long allocs; |
| #endif |
| }; |
| |
| struct dmabounce_device_info { |
| struct device *dev; |
| struct list_head safe_buffers; |
| #ifdef STATS |
| unsigned long total_allocs; |
| unsigned long map_op_count; |
| unsigned long bounce_count; |
| int attr_res; |
| #endif |
| struct dmabounce_pool small; |
| struct dmabounce_pool large; |
| |
| rwlock_t lock; |
| |
| int (*needs_bounce)(struct device *, dma_addr_t, size_t); |
| }; |
| |
| #ifdef STATS |
| static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct dmabounce_device_info *device_info = dev->archdata.dmabounce; |
| return sprintf(buf, "%lu %lu %lu %lu %lu %lu\n", |
| device_info->small.allocs, |
| device_info->large.allocs, |
| device_info->total_allocs - device_info->small.allocs - |
| device_info->large.allocs, |
| device_info->total_allocs, |
| device_info->map_op_count, |
| device_info->bounce_count); |
| } |
| |
| static DEVICE_ATTR(dmabounce_stats, 0400, dmabounce_show, NULL); |
| #endif |
| |
| |
| /* allocate a 'safe' buffer and keep track of it */ |
| static inline struct safe_buffer * |
| alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, |
| size_t size, enum dma_data_direction dir) |
| { |
| struct safe_buffer *buf; |
| struct dmabounce_pool *pool; |
| struct device *dev = device_info->dev; |
| unsigned long flags; |
| |
| dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n", |
| __func__, ptr, size, dir); |
| |
| if (size <= device_info->small.size) { |
| pool = &device_info->small; |
| } else if (size <= device_info->large.size) { |
| pool = &device_info->large; |
| } else { |
| pool = NULL; |
| } |
| |
| buf = kmalloc(sizeof(struct safe_buffer), GFP_ATOMIC); |
| if (buf == NULL) { |
| dev_warn(dev, "%s: kmalloc failed\n", __func__); |
| return NULL; |
| } |
| |
| buf->ptr = ptr; |
| buf->size = size; |
| buf->direction = dir; |
| buf->pool = pool; |
| |
| if (pool) { |
| buf->safe = dma_pool_alloc(pool->pool, GFP_ATOMIC, |
| &buf->safe_dma_addr); |
| } else { |
| buf->safe = dma_alloc_coherent(dev, size, &buf->safe_dma_addr, |
| GFP_ATOMIC); |
| } |
| |
| if (buf->safe == NULL) { |
| dev_warn(dev, |
| "%s: could not alloc dma memory (size=%d)\n", |
| __func__, size); |
| kfree(buf); |
| return NULL; |
| } |
| |
| #ifdef STATS |
| if (pool) |
| pool->allocs++; |
| device_info->total_allocs++; |
| #endif |
| |
| write_lock_irqsave(&device_info->lock, flags); |
| list_add(&buf->node, &device_info->safe_buffers); |
| write_unlock_irqrestore(&device_info->lock, flags); |
| |
| return buf; |
| } |
| |
| /* determine if a buffer is from our "safe" pool */ |
| static inline struct safe_buffer * |
| find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr) |
| { |
| struct safe_buffer *b, *rb = NULL; |
| unsigned long flags; |
| |
| read_lock_irqsave(&device_info->lock, flags); |
| |
| list_for_each_entry(b, &device_info->safe_buffers, node) |
| if (b->safe_dma_addr <= safe_dma_addr && |
| b->safe_dma_addr + b->size > safe_dma_addr) { |
| rb = b; |
| break; |
| } |
| |
| read_unlock_irqrestore(&device_info->lock, flags); |
| return rb; |
| } |
| |
| static inline void |
| free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf) |
| { |
| unsigned long flags; |
| |
| dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf); |
| |
| write_lock_irqsave(&device_info->lock, flags); |
| |
| list_del(&buf->node); |
| |
| write_unlock_irqrestore(&device_info->lock, flags); |
| |
| if (buf->pool) |
| dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr); |
| else |
| dma_free_coherent(device_info->dev, buf->size, buf->safe, |
| buf->safe_dma_addr); |
| |
| kfree(buf); |
| } |
| |
| /* ************************************************** */ |
| |
| static struct safe_buffer *find_safe_buffer_dev(struct device *dev, |
| dma_addr_t dma_addr, const char *where) |
| { |
| if (!dev || !dev->archdata.dmabounce) |
| return NULL; |
| if (dma_mapping_error(dev, dma_addr)) { |
| dev_err(dev, "Trying to %s invalid mapping\n", where); |
| return NULL; |
| } |
| return find_safe_buffer(dev->archdata.dmabounce, dma_addr); |
| } |
| |
| static int needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size) |
| { |
| if (!dev || !dev->archdata.dmabounce) |
| return 0; |
| |
| if (dev->dma_mask) { |
| unsigned long limit, mask = *dev->dma_mask; |
| |
| limit = (mask + 1) & ~mask; |
| if (limit && size > limit) { |
| dev_err(dev, "DMA mapping too big (requested %#x " |
| "mask %#Lx)\n", size, *dev->dma_mask); |
| return -E2BIG; |
| } |
| |
| /* Figure out if we need to bounce from the DMA mask. */ |
| if ((dma_addr | (dma_addr + size - 1)) & ~mask) |
| return 1; |
| } |
| |
| return !!dev->archdata.dmabounce->needs_bounce(dev, dma_addr, size); |
| } |
| |
| static inline dma_addr_t map_single(struct device *dev, void *ptr, size_t size, |
| enum dma_data_direction dir) |
| { |
| struct dmabounce_device_info *device_info = dev->archdata.dmabounce; |
| struct safe_buffer *buf; |
| |
| if (device_info) |
| DO_STATS ( device_info->map_op_count++ ); |
| |
| buf = alloc_safe_buffer(device_info, ptr, size, dir); |
| if (buf == NULL) { |
| dev_err(dev, "%s: unable to map unsafe buffer %p!\n", |
| __func__, ptr); |
| return DMA_ERROR_CODE; |
| } |
| |
| dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n", |
| __func__, buf->ptr, virt_to_dma(dev, buf->ptr), |
| buf->safe, buf->safe_dma_addr); |
| |
| if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) { |
| dev_dbg(dev, "%s: copy unsafe %p to safe %p, size %d\n", |
| __func__, ptr, buf->safe, size); |
| memcpy(buf->safe, ptr, size); |
| } |
| |
| return buf->safe_dma_addr; |
| } |
| |
| static inline void unmap_single(struct device *dev, struct safe_buffer *buf, |
| size_t size, enum dma_data_direction dir) |
| { |
| BUG_ON(buf->size != size); |
| BUG_ON(buf->direction != dir); |
| |
| dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x) mapped to %p (dma=%#x)\n", |
| __func__, buf->ptr, virt_to_dma(dev, buf->ptr), |
| buf->safe, buf->safe_dma_addr); |
| |
| DO_STATS(dev->archdata.dmabounce->bounce_count++); |
| |
| if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) { |
| void *ptr = buf->ptr; |
| |
| dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n", |
| __func__, buf->safe, ptr, size); |
| memcpy(ptr, buf->safe, size); |
| |
| /* |
| * Since we may have written to a page cache page, |
| * we need to ensure that the data will be coherent |
| * with user mappings. |
| */ |
| __cpuc_flush_dcache_area(ptr, size); |
| } |
| free_safe_buffer(dev->archdata.dmabounce, buf); |
| } |
| |
| /* ************************************************** */ |
| |
| /* |
| * see if a buffer address is in an 'unsafe' range. if it is |
| * allocate a 'safe' buffer and copy the unsafe buffer into it. |
| * substitute the safe buffer for the unsafe one. |
| * (basically move the buffer from an unsafe area to a safe one) |
| */ |
| static dma_addr_t dmabounce_map_page(struct device *dev, struct page *page, |
| unsigned long offset, size_t size, enum dma_data_direction dir, |
| struct dma_attrs *attrs) |
| { |
| dma_addr_t dma_addr; |
| int ret; |
| |
| dev_dbg(dev, "%s(page=%p,off=%#lx,size=%zx,dir=%x)\n", |
| __func__, page, offset, size, dir); |
| |
| dma_addr = pfn_to_dma(dev, page_to_pfn(page)) + offset; |
| |
| ret = needs_bounce(dev, dma_addr, size); |
| if (ret < 0) |
| return DMA_ERROR_CODE; |
| |
| if (ret == 0) { |
| arm_dma_ops.sync_single_for_device(dev, dma_addr, size, dir); |
| return dma_addr; |
| } |
| |
| if (PageHighMem(page)) { |
| dev_err(dev, "DMA buffer bouncing of HIGHMEM pages is not supported\n"); |
| return DMA_ERROR_CODE; |
| } |
| |
| return map_single(dev, page_address(page) + offset, size, dir); |
| } |
| |
| /* |
| * see if a mapped address was really a "safe" buffer and if so, copy |
| * the data from the safe buffer back to the unsafe buffer and free up |
| * the safe buffer. (basically return things back to the way they |
| * should be) |
| */ |
| static void dmabounce_unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir, struct dma_attrs *attrs) |
| { |
| struct safe_buffer *buf; |
| |
| dev_dbg(dev, "%s(dma=%#x,size=%d,dir=%x)\n", |
| __func__, dma_addr, size, dir); |
| |
| buf = find_safe_buffer_dev(dev, dma_addr, __func__); |
| if (!buf) { |
| arm_dma_ops.sync_single_for_cpu(dev, dma_addr, size, dir); |
| return; |
| } |
| |
| unmap_single(dev, buf, size, dir); |
| } |
| |
| static int __dmabounce_sync_for_cpu(struct device *dev, dma_addr_t addr, |
| size_t sz, enum dma_data_direction dir) |
| { |
| struct safe_buffer *buf; |
| unsigned long off; |
| |
| dev_dbg(dev, "%s(dma=%#x,sz=%zx,dir=%x)\n", |
| __func__, addr, sz, dir); |
| |
| buf = find_safe_buffer_dev(dev, addr, __func__); |
| if (!buf) |
| return 1; |
| |
| off = addr - buf->safe_dma_addr; |
| |
| BUG_ON(buf->direction != dir); |
| |
| dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n", |
| __func__, buf->ptr, virt_to_dma(dev, buf->ptr), off, |
| buf->safe, buf->safe_dma_addr); |
| |
| DO_STATS(dev->archdata.dmabounce->bounce_count++); |
| |
| if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL) { |
| dev_dbg(dev, "%s: copy back safe %p to unsafe %p size %d\n", |
| __func__, buf->safe + off, buf->ptr + off, sz); |
| memcpy(buf->ptr + off, buf->safe + off, sz); |
| } |
| return 0; |
| } |
| |
| static void dmabounce_sync_for_cpu(struct device *dev, |
| dma_addr_t handle, size_t size, enum dma_data_direction dir) |
| { |
| if (!__dmabounce_sync_for_cpu(dev, handle, size, dir)) |
| return; |
| |
| arm_dma_ops.sync_single_for_cpu(dev, handle, size, dir); |
| } |
| |
| static int __dmabounce_sync_for_device(struct device *dev, dma_addr_t addr, |
| size_t sz, enum dma_data_direction dir) |
| { |
| struct safe_buffer *buf; |
| unsigned long off; |
| |
| dev_dbg(dev, "%s(dma=%#x,sz=%zx,dir=%x)\n", |
| __func__, addr, sz, dir); |
| |
| buf = find_safe_buffer_dev(dev, addr, __func__); |
| if (!buf) |
| return 1; |
| |
| off = addr - buf->safe_dma_addr; |
| |
| BUG_ON(buf->direction != dir); |
| |
| dev_dbg(dev, "%s: unsafe buffer %p (dma=%#x off=%#lx) mapped to %p (dma=%#x)\n", |
| __func__, buf->ptr, virt_to_dma(dev, buf->ptr), off, |
| buf->safe, buf->safe_dma_addr); |
| |
| DO_STATS(dev->archdata.dmabounce->bounce_count++); |
| |
| if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL) { |
| dev_dbg(dev, "%s: copy out unsafe %p to safe %p, size %d\n", |
| __func__,buf->ptr + off, buf->safe + off, sz); |
| memcpy(buf->safe + off, buf->ptr + off, sz); |
| } |
| return 0; |
| } |
| |
| static void dmabounce_sync_for_device(struct device *dev, |
| dma_addr_t handle, size_t size, enum dma_data_direction dir) |
| { |
| if (!__dmabounce_sync_for_device(dev, handle, size, dir)) |
| return; |
| |
| arm_dma_ops.sync_single_for_device(dev, handle, size, dir); |
| } |
| |
| static int dmabounce_set_mask(struct device *dev, u64 dma_mask) |
| { |
| if (dev->archdata.dmabounce) |
| return 0; |
| |
| return arm_dma_ops.set_dma_mask(dev, dma_mask); |
| } |
| |
| static struct dma_map_ops dmabounce_ops = { |
| .alloc = arm_dma_alloc, |
| .free = arm_dma_free, |
| .mmap = arm_dma_mmap, |
| .map_page = dmabounce_map_page, |
| .unmap_page = dmabounce_unmap_page, |
| .sync_single_for_cpu = dmabounce_sync_for_cpu, |
| .sync_single_for_device = dmabounce_sync_for_device, |
| .map_sg = arm_dma_map_sg, |
| .unmap_sg = arm_dma_unmap_sg, |
| .sync_sg_for_cpu = arm_dma_sync_sg_for_cpu, |
| .sync_sg_for_device = arm_dma_sync_sg_for_device, |
| .set_dma_mask = dmabounce_set_mask, |
| }; |
| |
| static int dmabounce_init_pool(struct dmabounce_pool *pool, struct device *dev, |
| const char *name, unsigned long size) |
| { |
| pool->size = size; |
| DO_STATS(pool->allocs = 0); |
| pool->pool = dma_pool_create(name, dev, size, |
| 0 /* byte alignment */, |
| 0 /* no page-crossing issues */); |
| |
| return pool->pool ? 0 : -ENOMEM; |
| } |
| |
| int dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size, |
| unsigned long large_buffer_size, |
| int (*needs_bounce_fn)(struct device *, dma_addr_t, size_t)) |
| { |
| struct dmabounce_device_info *device_info; |
| int ret; |
| |
| device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC); |
| if (!device_info) { |
| dev_err(dev, |
| "Could not allocated dmabounce_device_info\n"); |
| return -ENOMEM; |
| } |
| |
| ret = dmabounce_init_pool(&device_info->small, dev, |
| "small_dmabounce_pool", small_buffer_size); |
| if (ret) { |
| dev_err(dev, |
| "dmabounce: could not allocate DMA pool for %ld byte objects\n", |
| small_buffer_size); |
| goto err_free; |
| } |
| |
| if (large_buffer_size) { |
| ret = dmabounce_init_pool(&device_info->large, dev, |
| "large_dmabounce_pool", |
| large_buffer_size); |
| if (ret) { |
| dev_err(dev, |
| "dmabounce: could not allocate DMA pool for %ld byte objects\n", |
| large_buffer_size); |
| goto err_destroy; |
| } |
| } |
| |
| device_info->dev = dev; |
| INIT_LIST_HEAD(&device_info->safe_buffers); |
| rwlock_init(&device_info->lock); |
| device_info->needs_bounce = needs_bounce_fn; |
| |
| #ifdef STATS |
| device_info->total_allocs = 0; |
| device_info->map_op_count = 0; |
| device_info->bounce_count = 0; |
| device_info->attr_res = device_create_file(dev, &dev_attr_dmabounce_stats); |
| #endif |
| |
| dev->archdata.dmabounce = device_info; |
| set_dma_ops(dev, &dmabounce_ops); |
| |
| dev_info(dev, "dmabounce: registered device\n"); |
| |
| return 0; |
| |
| err_destroy: |
| dma_pool_destroy(device_info->small.pool); |
| err_free: |
| kfree(device_info); |
| return ret; |
| } |
| EXPORT_SYMBOL(dmabounce_register_dev); |
| |
| void dmabounce_unregister_dev(struct device *dev) |
| { |
| struct dmabounce_device_info *device_info = dev->archdata.dmabounce; |
| |
| dev->archdata.dmabounce = NULL; |
| set_dma_ops(dev, NULL); |
| |
| if (!device_info) { |
| dev_warn(dev, |
| "Never registered with dmabounce but attempting" |
| "to unregister!\n"); |
| return; |
| } |
| |
| if (!list_empty(&device_info->safe_buffers)) { |
| dev_err(dev, |
| "Removing from dmabounce with pending buffers!\n"); |
| BUG(); |
| } |
| |
| if (device_info->small.pool) |
| dma_pool_destroy(device_info->small.pool); |
| if (device_info->large.pool) |
| dma_pool_destroy(device_info->large.pool); |
| |
| #ifdef STATS |
| if (device_info->attr_res == 0) |
| device_remove_file(dev, &dev_attr_dmabounce_stats); |
| #endif |
| |
| kfree(device_info); |
| |
| dev_info(dev, "dmabounce: device unregistered\n"); |
| } |
| EXPORT_SYMBOL(dmabounce_unregister_dev); |
| |
| MODULE_AUTHOR("Christopher Hoover <ch@hpl.hp.com>, Deepak Saxena <dsaxena@plexity.net>"); |
| MODULE_DESCRIPTION("Special dma_{map/unmap/dma_sync}_* routines for systems with limited DMA windows"); |
| MODULE_LICENSE("GPL"); |