path: root/recipes/linux/linux-rp-2.6.23/arm-dma-coherent.patch

Patch largely based on the work of Ian Molton (spyro@f2s.com).

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Index: linux-2.6.23/arch/arm/mm/consistent.c
===================================================================
--- linux-2.6.23.orig/arch/arm/mm/consistent.c	2007-10-10 00:31:38.000000000 +0400
+++ linux-2.6.23/arch/arm/mm/consistent.c	2007-11-13 01:20:58.281143408 +0300
@@ -3,6 +3,8 @@
  *
  *  Copyright (C) 2000-2004 Russell King
  *
+ *  Device local coherent memory support added by Ian Molton (spyro@f2s.com)
+ *
  * 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.
@@ -20,6 +22,7 @@
 
 #include <asm/memory.h>
 #include <asm/cacheflush.h>
+#include <asm/io.h>
 #include <asm/tlbflush.h>
 #include <asm/sizes.h>
 
@@ -35,6 +38,13 @@
 #define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)
 #define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)
 
+struct dma_coherent_mem {
+	void		*virt_base;
+	u32		device_base;
+	int		size;
+	int		flags;
+	unsigned long	*bitmap;
+};
 
 /*
  * These are the page tables (2MB each) covering uncached, DMA consistent allocations
@@ -153,6 +163,13 @@
 	unsigned long order;
 	u64 mask = ISA_DMA_THRESHOLD, limit;
 
+	/* Following is a work-around (a.k.a. hack) to prevent pages
+	 * with __GFP_COMP being passed to split_page() which cannot
+	 * handle them.  The real problem is that this flag probably
+	 * should be 0 on ARM as it is not supported on this
+	 * platform--see CONFIG_HUGETLB_PAGE. */
+	gfp &= ~(__GFP_COMP);
+
 	if (!consistent_pte[0]) {
 		printk(KERN_ERR "%s: not initialised\n", __func__);
 		dump_stack();
@@ -160,6 +177,26 @@
 	}
 
 	if (dev) {
+
+		if (dev->dma_mem) {
+			unsigned long flags;
+			int page;
+			void *ret;
+
+			spin_lock_irqsave(&consistent_lock, flags);
+			page = bitmap_find_free_region(dev->dma_mem->bitmap,
+						       dev->dma_mem->size,
+						       get_order(size));
+			spin_unlock_irqrestore(&consistent_lock, flags);
+
+			if (page >= 0) {
+				*handle = dev->dma_mem->device_base + (page << PAGE_SHIFT);
+				ret = dev->dma_mem->virt_base + (page << PAGE_SHIFT);
+				memset(ret, 0, size);
+				return ret;
+			}
+		}
+
 		mask = dev->coherent_dma_mask;
 
 		/*
@@ -177,6 +214,9 @@
 				 mask, (unsigned long long)ISA_DMA_THRESHOLD);
 			goto no_page;
 		}
+
+		if (dev->dma_mem && dev->dma_mem->flags & DMA_MEMORY_EXCLUSIVE)
+			return NULL;
 	}
 
 	/*
@@ -360,6 +400,8 @@
 	pte_t *ptep;
 	int idx;
 	u32 off;
+	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
+	unsigned long order;
 
 	WARN_ON(irqs_disabled());
 
@@ -369,6 +411,15 @@
 	}
 
 	size = PAGE_ALIGN(size);
+	order = get_order(size);
+
+	/* What if mem is valid and the range is not? */
+	if (mem && cpu_addr >= mem->virt_base && cpu_addr < (mem->virt_base + (mem->size << PAGE_SHIFT))) {
+		int page = (cpu_addr - mem->virt_base) >> PAGE_SHIFT;
+
+		bitmap_release_region(mem->bitmap, page, order);
+		return;
+	}
 
 	spin_lock_irqsave(&consistent_lock, flags);
 	c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);
@@ -438,6 +489,81 @@
 }
 EXPORT_SYMBOL(dma_free_coherent);
 
+int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+				dma_addr_t device_addr, size_t size, int flags)
+{
+	void *mem_base;
+	int pages = size >> PAGE_SHIFT;
+	int bitmap_size = (pages + 31)/32;
+
+	if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
+		goto out;
+	if (!size)
+		goto out;
+	if (dev->dma_mem)
+		goto out;
+
+	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
+	mem_base = ioremap_nocache(bus_addr, size);
+	if (!mem_base)
+		goto out;
+
+	dev->dma_mem = kmalloc(GFP_KERNEL, sizeof(struct dma_coherent_mem));
+	if (!dev->dma_mem)
+		goto out;
+	memset(dev->dma_mem, 0, sizeof(struct dma_coherent_mem));
+	dev->dma_mem->bitmap = kmalloc(GFP_KERNEL, bitmap_size);
+	if (!dev->dma_mem->bitmap)
+		goto free1_out;
+	memset(dev->dma_mem->bitmap, 0, bitmap_size);
+
+	dev->dma_mem->virt_base = mem_base;
+	dev->dma_mem->device_base = device_addr;
+	dev->dma_mem->size = pages;
+	dev->dma_mem->flags = flags;
+
+	if (flags & DMA_MEMORY_MAP)
+		return DMA_MEMORY_MAP;
+
+	return DMA_MEMORY_IO;
+
+ free1_out:
+	kfree(dev->dma_mem->bitmap);
+ out:
+	return 0;
+}
+EXPORT_SYMBOL(dma_declare_coherent_memory);
+
+void dma_release_declared_memory(struct device *dev)
+{
+	struct dma_coherent_mem *mem = dev->dma_mem;
+
+	if (!mem)
+		return;
+	dev->dma_mem = NULL;
+	kfree(mem->bitmap);
+	kfree(mem);
+}
+EXPORT_SYMBOL(dma_release_declared_memory);
+
+void *dma_mark_declared_memory_occupied(struct device *dev,
+					dma_addr_t device_addr, size_t size)
+{
+	struct dma_coherent_mem *mem = dev->dma_mem;
+	int pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	int pos, err;
+
+	if (!mem)
+		return ERR_PTR(-EINVAL);
+
+	pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
+	err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
+	if (err != 0)
+		return ERR_PTR(err);
+	return mem->virt_base + (pos << PAGE_SHIFT);
+}
+EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
+
 /*
  * Initialise the consistent memory allocation.
  */
Index: linux-2.6.23/arch/arm/common/dmabounce.c
===================================================================
--- linux-2.6.23.orig/arch/arm/common/dmabounce.c	2007-10-10 00:31:38.000000000 +0400
+++ linux-2.6.23/arch/arm/common/dmabounce.c	2007-11-13 01:23:17.452501736 +0300
@@ -16,6 +16,7 @@
  *
  *  Copyright (C) 2002 Hewlett Packard Company.
  *  Copyright (C) 2004 MontaVista Software, Inc.
+ *  Copyright (C) 2007 Dmitry Baryshkov <dbaryshkov@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU General Public License
@@ -29,6 +30,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/dmapool.h>
 #include <linux/list.h>
+#include <linux/rwsem.h>
 
 #include <asm/cacheflush.h>
 
@@ -79,6 +81,75 @@
 	rwlock_t lock;
 };
 
+struct dmabounce_check_entry {
+	struct list_head	list;
+	dmabounce_check		checker;
+	void			*data;
+};
+
+static struct list_head checkers = LIST_HEAD_INIT(checkers);
+static rwlock_t checkers_lock = RW_LOCK_UNLOCKED;
+
+int
+dmabounce_register_checker(dmabounce_check function, void *data)
+{
+	unsigned long flags;
+	struct dmabounce_check_entry *entry =
+		kzalloc(sizeof(struct dmabounce_check_entry), GFP_ATOMIC);
+
+	if (!entry)
+		return ENOMEM;
+
+	INIT_LIST_HEAD(&entry->list);
+	entry->checker = function;
+	entry->data = data;
+
+	write_lock_irqsave(checkers_lock, flags);
+	list_add(&entry->list, &checkers);
+	write_unlock_irqrestore(checkers_lock, flags);
+
+	return 0;
+}
+
+void
+dmabounce_remove_checker(dmabounce_check function, void *data)
+{
+	unsigned long flags;
+	struct list_head *pos;
+
+	write_lock_irqsave(checkers_lock, flags);
+	__list_for_each(pos, &checkers) {
+		struct dmabounce_check_entry *entry = container_of(pos,
+				struct dmabounce_check_entry, list);
+		if (entry->checker == function && entry->data == data) {
+			list_del(pos);
+			write_unlock_irqrestore(checkers_lock, flags);
+			kfree(entry);
+			return;
+		}
+	}
+
+	printk(KERN_WARNING "dmabounce checker not found: %p\n", function);
+}
+
+int dma_needs_bounce(struct device *dev, dma_addr_t dma, size_t size)
+{
+	unsigned long flags;
+	struct list_head *pos;
+
+	read_lock_irqsave(checkers_lock, flags);
+	__list_for_each(pos, &checkers) {
+		struct dmabounce_check_entry *entry = container_of(pos,
+				struct dmabounce_check_entry, list);
+		if (entry->checker(dev, dma, size, entry->data)) {
+			read_unlock_irqrestore(checkers_lock, flags);
+			return 1;
+		}
+	}
+
+	read_unlock_irqrestore(checkers_lock, flags);
+	return 0;
+}
 #ifdef STATS
 static ssize_t dmabounce_show(struct device *dev, struct device_attribute *attr,
 			      char *buf)
@@ -642,7 +713,6 @@
 		dev->bus_id, dev->bus->name);
 }
 
-
 EXPORT_SYMBOL(dma_map_single);
 EXPORT_SYMBOL(dma_unmap_single);
 EXPORT_SYMBOL(dma_map_sg);
@@ -652,6 +722,9 @@
 EXPORT_SYMBOL(dma_sync_sg);
 EXPORT_SYMBOL(dmabounce_register_dev);
 EXPORT_SYMBOL(dmabounce_unregister_dev);
+EXPORT_SYMBOL(dmabounce_register_checker);
+EXPORT_SYMBOL(dmabounce_remove_checker);
+
 
 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");
Index: linux-2.6.23/include/asm-arm/dma-mapping.h
===================================================================
--- linux-2.6.23.orig/include/asm-arm/dma-mapping.h	2007-10-10 00:31:38.000000000 +0400
+++ linux-2.6.23/include/asm-arm/dma-mapping.h	2007-11-13 01:24:05.588500474 +0300
@@ -7,6 +7,18 @@
 
 #include <asm/scatterlist.h>
 
+#define ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY
+extern int
+dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+			    dma_addr_t device_addr, size_t size, int flags);
+
+extern void
+dma_release_declared_memory(struct device *dev);
+
+extern void *
+dma_mark_declared_memory_occupied(struct device *dev,
+				  dma_addr_t device_addr, size_t size);
+
 /*
  * DMA-consistent mapping functions.  These allocate/free a region of
  * uncached, unwrite-buffered mapped memory space for use with DMA
@@ -433,23 +445,10 @@
  */
 extern void dmabounce_unregister_dev(struct device *);
 
-/**
- * dma_needs_bounce
- *
- * @dev: valid struct device pointer
- * @dma_handle: dma_handle of unbounced buffer
- * @size: size of region being mapped
- *
- * Platforms that utilize the dmabounce mechanism must implement
- * this function.
- *
- * The dmabounce routines call this function whenever a dma-mapping
- * is requested to determine whether a given buffer needs to be bounced
- * or not. The function must return 0 if the buffer is OK for
- * DMA access and 1 if the buffer needs to be bounced.
- *
- */
-extern int dma_needs_bounce(struct device*, dma_addr_t, size_t);
+typedef int (*dmabounce_check)(struct device *dev, dma_addr_t dma, size_t size, void *data);
+extern int dmabounce_register_checker(dmabounce_check, void *data);
+extern void dmabounce_remove_checker(dmabounce_check, void *data);
+
 #endif /* CONFIG_DMABOUNCE */
 
 #endif /* __KERNEL__ */