| /* |
| * 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 discontigous |
| * 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/device.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/dmapool.h> |
| #include <linux/list.h> |
| |
| #include <asm/cacheflush.h> |
| |
| #undef DEBUG |
| #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 list_head node; |
| |
| struct device *dev; |
| struct list_head safe_buffers; |
| #ifdef STATS |
| unsigned long total_allocs; |
| unsigned long map_op_count; |
| unsigned long bounce_count; |
| #endif |
| struct dmabounce_pool small; |
| struct dmabounce_pool large; |
| |
| rwlock_t lock; |
| }; |
| |
| static LIST_HEAD(dmabounce_devs); |
| |
| #ifdef STATS |
| static void print_alloc_stats(struct dmabounce_device_info *device_info) |
| { |
| printk(KERN_INFO |
| "%s: dmabounce: sbp: %lu, lbp: %lu, other: %lu, total: %lu\n", |
| device_info->dev->bus_id, |
| device_info->small.allocs, device_info->large.allocs, |
| device_info->total_allocs - device_info->small.allocs - |
| device_info->large.allocs, |
| device_info->total_allocs); |
| } |
| #endif |
| |
| /* find the given device in the dmabounce device list */ |
| static inline struct dmabounce_device_info * |
| find_dmabounce_dev(struct device *dev) |
| { |
| struct dmabounce_device_info *d; |
| |
| list_for_each_entry(d, &dmabounce_devs, node) |
| if (d->dev == dev) |
| return d; |
| |
| return NULL; |
| } |
| |
| |
| /* 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++; |
| if (device_info->total_allocs % 1000 == 0) |
| print_alloc_stats(device_info); |
| #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) { |
| 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); |
| } |
| |
| /* ************************************************** */ |
| |
| #ifdef STATS |
| static void print_map_stats(struct dmabounce_device_info *device_info) |
| { |
| dev_info(device_info->dev, |
| "dmabounce: map_op_count=%lu, bounce_count=%lu\n", |
| device_info->map_op_count, device_info->bounce_count); |
| } |
| #endif |
| |
| 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 = find_dmabounce_dev(dev); |
| dma_addr_t dma_addr; |
| int needs_bounce = 0; |
| |
| if (device_info) |
| DO_STATS ( device_info->map_op_count++ ); |
| |
| dma_addr = virt_to_dma(dev, ptr); |
| |
| if (dev->dma_mask) { |
| unsigned long mask = *dev->dma_mask; |
| unsigned long limit; |
| |
| 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 ~0; |
| } |
| |
| /* |
| * Figure out if we need to bounce from the DMA mask. |
| */ |
| needs_bounce = (dma_addr | (dma_addr + size - 1)) & ~mask; |
| } |
| |
| if (device_info && (needs_bounce || dma_needs_bounce(dev, dma_addr, size))) { |
| struct safe_buffer *buf; |
| |
| buf = alloc_safe_buffer(device_info, ptr, size, dir); |
| if (buf == 0) { |
| dev_err(dev, "%s: unable to map unsafe buffer %p!\n", |
| __func__, ptr); |
| return 0; |
| } |
| |
| dev_dbg(dev, |
| "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n", |
| __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr), |
| buf->safe, (void *) 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); |
| } |
| ptr = buf->safe; |
| |
| dma_addr = buf->safe_dma_addr; |
| } else { |
| /* |
| * We don't need to sync the DMA buffer since |
| * it was allocated via the coherent allocators. |
| */ |
| consistent_sync(ptr, size, dir); |
| } |
| |
| return dma_addr; |
| } |
| |
| static inline void |
| unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir) |
| { |
| struct dmabounce_device_info *device_info = find_dmabounce_dev(dev); |
| struct safe_buffer *buf = NULL; |
| |
| /* |
| * Trying to unmap an invalid mapping |
| */ |
| if (dma_mapping_error(dma_addr)) { |
| dev_err(dev, "Trying to unmap invalid mapping\n"); |
| return; |
| } |
| |
| if (device_info) |
| buf = find_safe_buffer(device_info, dma_addr); |
| |
| if (buf) { |
| BUG_ON(buf->size != size); |
| |
| dev_dbg(dev, |
| "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n", |
| __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr), |
| buf->safe, (void *) buf->safe_dma_addr); |
| |
| DO_STATS ( device_info->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); |
| |
| /* |
| * DMA buffers must have the same cache properties |
| * as if they were really used for DMA - which means |
| * data must be written back to RAM. Note that |
| * we don't use dmac_flush_range() here for the |
| * bidirectional case because we know the cache |
| * lines will be coherent with the data written. |
| */ |
| dmac_clean_range(ptr, ptr + size); |
| outer_clean_range(__pa(ptr), __pa(ptr) + size); |
| } |
| free_safe_buffer(device_info, buf); |
| } |
| } |
| |
| static inline void |
| sync_single(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir) |
| { |
| struct dmabounce_device_info *device_info = find_dmabounce_dev(dev); |
| struct safe_buffer *buf = NULL; |
| |
| if (device_info) |
| buf = find_safe_buffer(device_info, dma_addr); |
| |
| if (buf) { |
| /* |
| * Both of these checks from original code need to be |
| * commented out b/c some drivers rely on the following: |
| * |
| * 1) Drivers may map a large chunk of memory into DMA space |
| * but only sync a small portion of it. Good example is |
| * allocating a large buffer, mapping it, and then |
| * breaking it up into small descriptors. No point |
| * in syncing the whole buffer if you only have to |
| * touch one descriptor. |
| * |
| * 2) Buffers that are mapped as DMA_BIDIRECTIONAL are |
| * usually only synced in one dir at a time. |
| * |
| * See drivers/net/eepro100.c for examples of both cases. |
| * |
| * -ds |
| * |
| * BUG_ON(buf->size != size); |
| * BUG_ON(buf->direction != dir); |
| */ |
| |
| dev_dbg(dev, |
| "%s: unsafe buffer %p (phy=%p) mapped to %p (phy=%p)\n", |
| __func__, buf->ptr, (void *) virt_to_dma(dev, buf->ptr), |
| buf->safe, (void *) buf->safe_dma_addr); |
| |
| DO_STATS ( device_info->bounce_count++ ); |
| |
| switch (dir) { |
| case DMA_FROM_DEVICE: |
| dev_dbg(dev, |
| "%s: copy back safe %p to unsafe %p size %d\n", |
| __func__, buf->safe, buf->ptr, size); |
| memcpy(buf->ptr, buf->safe, size); |
| break; |
| case DMA_TO_DEVICE: |
| dev_dbg(dev, |
| "%s: copy out unsafe %p to safe %p, size %d\n", |
| __func__,buf->ptr, buf->safe, size); |
| memcpy(buf->safe, buf->ptr, size); |
| break; |
| case DMA_BIDIRECTIONAL: |
| BUG(); /* is this allowed? what does it mean? */ |
| default: |
| BUG(); |
| } |
| /* |
| * No need to sync the safe buffer - it was allocated |
| * via the coherent allocators. |
| */ |
| } else { |
| consistent_sync(dma_to_virt(dev, dma_addr), size, dir); |
| } |
| } |
| |
| /* ************************************************** */ |
| |
| /* |
| * 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) |
| */ |
| dma_addr_t |
| dma_map_single(struct device *dev, void *ptr, size_t size, |
| enum dma_data_direction dir) |
| { |
| dma_addr_t dma_addr; |
| |
| dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", |
| __func__, ptr, size, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| dma_addr = map_single(dev, ptr, size, dir); |
| |
| return dma_addr; |
| } |
| |
| /* |
| * 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) |
| */ |
| |
| void |
| dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir) |
| { |
| dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", |
| __func__, (void *) dma_addr, size, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| unmap_single(dev, dma_addr, size, dir); |
| } |
| |
| int |
| dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, |
| enum dma_data_direction dir) |
| { |
| int i; |
| |
| dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", |
| __func__, sg, nents, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| for (i = 0; i < nents; i++, sg++) { |
| struct page *page = sg->page; |
| unsigned int offset = sg->offset; |
| unsigned int length = sg->length; |
| void *ptr = page_address(page) + offset; |
| |
| sg->dma_address = |
| map_single(dev, ptr, length, dir); |
| } |
| |
| return nents; |
| } |
| |
| void |
| dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, |
| enum dma_data_direction dir) |
| { |
| int i; |
| |
| dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", |
| __func__, sg, nents, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| for (i = 0; i < nents; i++, sg++) { |
| dma_addr_t dma_addr = sg->dma_address; |
| unsigned int length = sg->length; |
| |
| unmap_single(dev, dma_addr, length, dir); |
| } |
| } |
| |
| void |
| dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir) |
| { |
| dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", |
| __func__, (void *) dma_addr, size, dir); |
| |
| sync_single(dev, dma_addr, size, dir); |
| } |
| |
| void |
| dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size, |
| enum dma_data_direction dir) |
| { |
| dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n", |
| __func__, (void *) dma_addr, size, dir); |
| |
| sync_single(dev, dma_addr, size, dir); |
| } |
| |
| void |
| dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, |
| enum dma_data_direction dir) |
| { |
| int i; |
| |
| dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", |
| __func__, sg, nents, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| for (i = 0; i < nents; i++, sg++) { |
| dma_addr_t dma_addr = sg->dma_address; |
| unsigned int length = sg->length; |
| |
| sync_single(dev, dma_addr, length, dir); |
| } |
| } |
| |
| void |
| dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, |
| enum dma_data_direction dir) |
| { |
| int i; |
| |
| dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n", |
| __func__, sg, nents, dir); |
| |
| BUG_ON(dir == DMA_NONE); |
| |
| for (i = 0; i < nents; i++, sg++) { |
| dma_addr_t dma_addr = sg->dma_address; |
| unsigned int length = sg->length; |
| |
| sync_single(dev, dma_addr, length, dir); |
| } |
| } |
| |
| 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) |
| { |
| struct dmabounce_device_info *device_info; |
| int ret; |
| |
| device_info = kmalloc(sizeof(struct dmabounce_device_info), GFP_ATOMIC); |
| if (!device_info) { |
| printk(KERN_ERR |
| "Could not allocated dmabounce_device_info for %s", |
| dev->bus_id); |
| 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); |
| |
| #ifdef STATS |
| device_info->total_allocs = 0; |
| device_info->map_op_count = 0; |
| device_info->bounce_count = 0; |
| #endif |
| |
| list_add(&device_info->node, &dmabounce_devs); |
| |
| printk(KERN_INFO "dmabounce: registered device %s on %s bus\n", |
| dev->bus_id, dev->bus->name); |
| |
| return 0; |
| |
| err_destroy: |
| dma_pool_destroy(device_info->small.pool); |
| err_free: |
| kfree(device_info); |
| return ret; |
| } |
| |
| void |
| dmabounce_unregister_dev(struct device *dev) |
| { |
| struct dmabounce_device_info *device_info = find_dmabounce_dev(dev); |
| |
| if (!device_info) { |
| printk(KERN_WARNING |
| "%s: Never registered with dmabounce but attempting" \ |
| "to unregister!\n", dev->bus_id); |
| return; |
| } |
| |
| if (!list_empty(&device_info->safe_buffers)) { |
| printk(KERN_ERR |
| "%s: Removing from dmabounce with pending buffers!\n", |
| dev->bus_id); |
| 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 |
| print_alloc_stats(device_info); |
| print_map_stats(device_info); |
| #endif |
| |
| list_del(&device_info->node); |
| |
| kfree(device_info); |
| |
| printk(KERN_INFO "dmabounce: device %s on %s bus unregistered\n", |
| dev->bus_id, dev->bus->name); |
| } |
| |
| |
| EXPORT_SYMBOL(dma_map_single); |
| EXPORT_SYMBOL(dma_unmap_single); |
| EXPORT_SYMBOL(dma_map_sg); |
| EXPORT_SYMBOL(dma_unmap_sg); |
| EXPORT_SYMBOL(dma_sync_single_for_cpu); |
| EXPORT_SYMBOL(dma_sync_single_for_device); |
| EXPORT_SYMBOL(dma_sync_sg); |
| EXPORT_SYMBOL(dmabounce_register_dev); |
| 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"); |