uio: introduce UIO_MEM_DMA_COHERENT type
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>
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@ -24,6 +24,7 @@
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#include <linux/kobject.h>
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#include <linux/cdev.h>
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#include <linux/uio_driver.h>
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#include <linux/dma-mapping.h>
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#define UIO_MAX_DEVICES (1U << MINORBITS)
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@ -759,6 +760,49 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
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vma->vm_page_prot);
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}
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static int uio_mmap_dma_coherent(struct vm_area_struct *vma)
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{
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struct uio_device *idev = vma->vm_private_data;
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struct uio_mem *mem;
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void *addr;
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int ret = 0;
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int mi;
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mi = uio_find_mem_index(vma);
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if (mi < 0)
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return -EINVAL;
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mem = idev->info->mem + mi;
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if (mem->addr & ~PAGE_MASK)
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return -ENODEV;
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if (mem->dma_addr & ~PAGE_MASK)
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return -ENODEV;
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if (!mem->dma_device)
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return -ENODEV;
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if (vma->vm_end - vma->vm_start > mem->size)
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return -EINVAL;
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dev_warn(mem->dma_device,
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"use of UIO_MEM_DMA_COHERENT is highly discouraged");
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/*
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* UIO uses offset to index into the maps for a device.
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* We need to clear vm_pgoff for dma_mmap_coherent.
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*/
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vma->vm_pgoff = 0;
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addr = (void *)mem->addr;
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ret = dma_mmap_coherent(mem->dma_device,
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vma,
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addr,
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mem->dma_addr,
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vma->vm_end - vma->vm_start);
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vma->vm_pgoff = mi;
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return ret;
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}
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static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
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{
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struct uio_listener *listener = filep->private_data;
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@ -806,6 +850,9 @@ static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
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case UIO_MEM_VIRTUAL:
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ret = uio_mmap_logical(vma);
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break;
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case UIO_MEM_DMA_COHERENT:
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ret = uio_mmap_dma_coherent(vma);
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break;
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default:
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ret = -EINVAL;
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}
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@ -28,19 +28,26 @@ struct uio_map;
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* logical, virtual, or physical & phys_addr_t
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* should always be large enough to handle any of
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* the address types)
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* @dma_addr: DMA handle set by dma_alloc_coherent, used with
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* UIO_MEM_DMA_COHERENT only (@addr should be the
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* void * returned from the same dma_alloc_coherent call)
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* @offs: offset of device memory within the page
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* @size: size of IO (multiple of page size)
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* @memtype: type of memory addr points to
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* @internal_addr: ioremap-ped version of addr, for driver internal use
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* @dma_device: device struct that was passed to dma_alloc_coherent,
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* used with UIO_MEM_DMA_COHERENT only
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* @map: for use by the UIO core only.
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*/
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struct uio_mem {
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const char *name;
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phys_addr_t addr;
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dma_addr_t dma_addr;
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unsigned long offs;
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resource_size_t size;
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int memtype;
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void __iomem *internal_addr;
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struct device *dma_device;
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struct uio_map *map;
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};
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@ -158,6 +165,12 @@ extern int __must_check
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#define UIO_MEM_LOGICAL 2
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#define UIO_MEM_VIRTUAL 3
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#define UIO_MEM_IOVA 4
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/*
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* UIO_MEM_DMA_COHERENT exists for legacy drivers that had been getting by with
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* improperly mapping DMA coherent allocations through the other modes.
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* Do not use in new drivers.
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*/
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#define UIO_MEM_DMA_COHERENT 5
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/* defines for uio_port->porttype */
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#define UIO_PORT_NONE 0
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