v4.19.13 snapshot.
diff --git a/arch/arm/common/dmabounce.c b/arch/arm/common/dmabounce.c
new file mode 100644
index 0000000..9a92de6
--- /dev/null
+++ b/arch/arm/common/dmabounce.c
@@ -0,0 +1,590 @@
+/*
+ * 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>
+#include <asm/dma-iommu.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,
+ unsigned long attrs)
+{
+ 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 ARM_MAPPING_ERROR;
+ }
+
+ 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) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+ 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,
+ unsigned long attrs)
+{
+ 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) &&
+ !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
+ 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,
+ unsigned long 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 ARM_MAPPING_ERROR;
+
+ 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 ARM_MAPPING_ERROR;
+ }
+
+ return map_single(dev, page_address(page) + offset, size, dir, attrs);
+}
+
+/*
+ * 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, unsigned long 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, attrs);
+}
+
+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_dma_supported(struct device *dev, u64 dma_mask)
+{
+ if (dev->archdata.dmabounce)
+ return 0;
+
+ return arm_dma_ops.dma_supported(dev, dma_mask);
+}
+
+static int dmabounce_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+ return arm_dma_ops.mapping_error(dev, dma_addr);
+}
+
+static const struct dma_map_ops dmabounce_ops = {
+ .alloc = arm_dma_alloc,
+ .free = arm_dma_free,
+ .mmap = arm_dma_mmap,
+ .get_sgtable = arm_dma_get_sgtable,
+ .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,
+ .dma_supported = dmabounce_dma_supported,
+ .mapping_error = dmabounce_mapping_error,
+};
+
+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");