/* 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; } EXPORT_SYMBOL(dma_alloc_coherent); 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(); } EXPORT_SYMBOL(dma_free_coherent); /* * 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); } EXPORT_SYMBOL(dma_map_single); /* * 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; } EXPORT_SYMBOL(dma_map_sg);