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uio: introduce UIO_MEM_DMA_COHERENT type

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Add a UIO memtype specifically for sharing dma_alloc_coherent
memory with userspace, backed by dma_mmap_coherent.

This is mainly for the bnx2/bnx2x/bnx2i "cnic" interface, although there
are a few other uio drivers which map dma_alloc_coherent memory and will
be converted to use dma_mmap_coherent as well.

Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Chris Leech <cleech@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240205200137.138302-1-cleech@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chris Leech 2024-02-05 12:01:37 -08:00 committed by Greg Kroah-Hartman
parent 0e439ba38e
commit 576882ef5e
2 changed files with 60 additions and 0 deletions
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47
drivers/uio/uio.c
View file

@ -24,6 +24,7 @@
#include <linux/kobject.h>
#include <linux/cdev.h>
#include <linux/uio_driver.h>
#include <linux/dma-mapping.h>
#define UIO_MAX_DEVICES (1U << MINORBITS)
@ -759,6 +760,49 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
vma->vm_page_prot);
}
static int uio_mmap_dma_coherent(struct vm_area_struct *vma)
{
struct uio_device *idev = vma->vm_private_data;
struct uio_mem *mem;
void *addr;
int ret = 0;
int mi;
mi = uio_find_mem_index(vma);
if (mi < 0)
return -EINVAL;
mem = idev->info->mem + mi;
if (mem->addr & ~PAGE_MASK)
return -ENODEV;
if (mem->dma_addr & ~PAGE_MASK)
return -ENODEV;
if (!mem->dma_device)
return -ENODEV;
if (vma->vm_end - vma->vm_start > mem->size)
return -EINVAL;
dev_warn(mem->dma_device,
"use of UIO_MEM_DMA_COHERENT is highly discouraged");
/*
* UIO uses offset to index into the maps for a device.
* We need to clear vm_pgoff for dma_mmap_coherent.
*/
vma->vm_pgoff = 0;
addr = (void *)mem->addr;
ret = dma_mmap_coherent(mem->dma_device,
vma,
addr,
mem->dma_addr,
vma->vm_end - vma->vm_start);
vma->vm_pgoff = mi;
return ret;
}
static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
{
struct uio_listener *listener = filep->private_data;
@ -806,6 +850,9 @@ static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
case UIO_MEM_VIRTUAL:
ret = uio_mmap_logical(vma);
break;
case UIO_MEM_DMA_COHERENT:
ret = uio_mmap_dma_coherent(vma);
break;
default:
ret = -EINVAL;
}

13
include/linux/uio_driver.h
View file

@ -28,19 +28,26 @@ struct uio_map;
* logical, virtual, or physical & phys_addr_t
* should always be large enough to handle any of
* the address types)
* @dma_addr: DMA handle set by dma_alloc_coherent, used with
* UIO_MEM_DMA_COHERENT only (@addr should be the
* void * returned from the same dma_alloc_coherent call)
* @offs: offset of device memory within the page
* @size: size of IO (multiple of page size)
* @memtype: type of memory addr points to
* @internal_addr: ioremap-ped version of addr, for driver internal use
* @dma_device: device struct that was passed to dma_alloc_coherent,
* used with UIO_MEM_DMA_COHERENT only
* @map: for use by the UIO core only.
*/
struct uio_mem {
const char *name;
phys_addr_t addr;
dma_addr_t dma_addr;
unsigned long offs;
resource_size_t size;
int memtype;
void __iomem *internal_addr;
struct device *dma_device;
struct uio_map *map;
};
@ -158,6 +165,12 @@ extern int __must_check
#define UIO_MEM_LOGICAL 2
#define UIO_MEM_VIRTUAL 3
#define UIO_MEM_IOVA 4
/*
* UIO_MEM_DMA_COHERENT exists for legacy drivers that had been getting by with
* improperly mapping DMA coherent allocations through the other modes.
* Do not use in new drivers.
*/
#define UIO_MEM_DMA_COHERENT 5
/* defines for uio_port->porttype */
#define UIO_PORT_NONE 0