/* pci-dma-nommu.c: Dynamic DMA mapping support for the FRV
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Woodhouse (dwmw2@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/list.h>
#include <linux/pci.h>
#include <asm/io.h>
#if 1
#define DMA_SRAM_START dma_coherent_mem_start
#define DMA_SRAM_END dma_coherent_mem_end
#else // Use video RAM on Matrox
#define DMA_SRAM_START 0xe8900000
#define DMA_SRAM_END 0xe8a00000
#endif
struct dma_alloc_record {
struct list_head list;
unsigned long ofs;
unsigned long len;
};
static DEFINE_SPINLOCK(dma_alloc_lock);
static LIST_HEAD(dma_alloc_list);
void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
{
struct dma_alloc_record *new;
struct list_head *this = &dma_alloc_list;
unsigned long flags;
unsigned long start = DMA_SRAM_START;
unsigned long end;
if (!DMA_SRAM_START) {
printk("%s called without any DMA area reserved!\n", __func__);
return NULL;
}
new = kmalloc(sizeof (*new), GFP_ATOMIC);
if (!new)
return NULL;
/* Round up to a reasonable alignment */
new->len = (size + 31) & ~31;
spin_lock_irqsave(&dma_alloc_lock, flags);
list_for_each (this, &dma_alloc_list) {
struct dma_alloc_record *this_r = list_entry(this, struct dma_alloc_record, list);
end = this_r->ofs;
if (end - start >= size)
goto gotone;
start = this_r->ofs + this_r->len;
}
/* Reached end of list. */
end = DMA_SRAM_END;
this = &dma_alloc_list;
if (end - start >= size) {
gotone:
new->ofs = start;
list_add_tail(&new->list, this);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
*dma_handle = start;
return (void *)start;
}
kfree(new);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
return NULL;
}
void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
{
struct dma_alloc_record *rec;
unsigned long flags;
spin_lock_irqsave(&dma_alloc_lock, flags);
list_for_each_entry(rec, &dma_alloc_list, list) {
if (rec->ofs == dma_handle) {
list_del(&rec->list);
kfree(rec);
spin_unlock_irqrestore(&dma_alloc_lock, flags);
return;
}
}
spin_unlock_irqrestore(&dma_alloc_lock, flags);
BUG();
}
/*
* Map a single buffer of the indicated size for DMA in streaming mode.
* The 32-bit bus address to use is returned.
*
* Once the device is given the dma address, the device owns this memory
* until either pci_unmap_single or pci_dma_sync_single is performed.
*/
dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
enum dma_data_direction direction)
{
if (direction == DMA_NONE)
BUG();
frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
return virt_to_bus(ptr);
}
/*
* Map a set of buffers described by scatterlist in streaming
* mode for DMA. This is the scather-gather version of the
* above pci_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 pci_map_single are
* the same here.
*/
int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
{
int i;
for (i=0; i<nents; i++)
frv_cache_wback_inv(sg_dma_address(&sg[i]),
sg_dma_address(&sg[i]) + sg_dma_len(&sg[i]));
if (direction == DMA_NONE)
BUG();
return nents;
}
