linux/arch/frv/mb93090-mb00/pci-dma-nommu.c
Krzysztof Kozlowski 00085f1efa dma-mapping: use unsigned long for dma_attrs
The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-04 08:50:07 -04:00

171 lines
4.1 KiB
C

/* 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@infradead.org)
*
* 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/export.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);
static void *frv_dma_alloc(struct device *hwdev, size_t size, dma_addr_t *dma_handle,
gfp_t gfp, unsigned long attrs)
{
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;
}
static void frv_dma_free(struct device *hwdev, size_t size, void *vaddr,
dma_addr_t dma_handle, unsigned long attrs)
{
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();
}
static int frv_dma_map_sg(struct device *dev, struct scatterlist *sglist,
int nents, enum dma_data_direction direction,
unsigned long attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sglist, sg, nents, i) {
frv_cache_wback_inv(sg_dma_address(sg),
sg_dma_address(sg) + sg_dma_len(sg));
}
BUG_ON(direction == DMA_NONE);
return nents;
}
static dma_addr_t frv_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction, unsigned long attrs)
{
BUG_ON(direction == DMA_NONE);
flush_dcache_page(page);
return (dma_addr_t) page_to_phys(page) + offset;
}
static void frv_dma_sync_single_for_device(struct device *dev,
dma_addr_t dma_handle, size_t size,
enum dma_data_direction direction)
{
flush_write_buffers();
}
static void frv_dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nelems,
enum dma_data_direction direction)
{
flush_write_buffers();
}
static int frv_dma_supported(struct device *dev, u64 mask)
{
/*
* we fall back to GFP_DMA when the mask isn't all 1s,
* so we can't guarantee allocations that must be
* within a tighter range than GFP_DMA..
*/
if (mask < 0x00ffffff)
return 0;
return 1;
}
struct dma_map_ops frv_dma_ops = {
.alloc = frv_dma_alloc,
.free = frv_dma_free,
.map_page = frv_dma_map_page,
.map_sg = frv_dma_map_sg,
.sync_single_for_device = frv_dma_sync_single_for_device,
.sync_sg_for_device = frv_dma_sync_sg_for_device,
.dma_supported = frv_dma_supported,
};
EXPORT_SYMBOL(frv_dma_ops);