Re: Mapping PCI memory to user-space
> I am writing a driver to map a PCI board memory space (pcibar2) into a
> user-space vma via 'mmap'. What is the relationship between the address
> returned from ioremap and the type of address needed in the
> 'io_remap_page_range' or 'remap_pfn_range' functions? How about the
> following? (I am developing under RHEL4 and a 2.6.9 kernel)
There is no relationship between the address returned from ioremap and
what you pass into io_remap_page_range(). ioremap gives you a kernel
virtual address for the PCI address you remap. io_remap_page_range()
creates a userspace mapping in the same way, and you should pass in
the PCI address exactly the same way you pass in the PCI address into
ioremap. io_remap_pfn_range() takes a PFN ("page frame number"),
which is basically the PCI address you want to map divided by
PAGE_SIZE. The main reason for using PFNs is that they allow you to
map addresses above 4G even if sizeof long is only 4.
In your code:
> dev.pcibar2 = ioremap_nocache(resource,size);
> dev.region_start = dev.pcibar2 + offset; // RAM is at some offset
> from base
This gives you a kernel mapping that you can use with readl(),
writel() etc to access the PCI memory from the kernel.
To map to userspace, this:
> if (io_remap_page_range(vma, phyaddr, vma->vm_start, vsize,
> vma->vm_page_prot))
should use phyaddr as you have it here:
> // phyaddr = physical address of PCI memory area
This is just wrong:
> unsigned long phy= __pa(dev->region_start + off);
__pa() doesn't work on addresses returned from ioremap. Just use the
same resource address you passed into ioremap.
- R.
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Re: Mapping PCI memory to user-space
I am writing a driver to map a PCI board memory space (pcibar2) into a user-space vma via 'mmap'. What is the relationship between the address returned from ioremap and the type of address needed in the 'io_remap_page_range' or 'remap_pfn_range' functions? How about the following? (I am developing under RHEL4 and a 2.6.9 kernel) There is no relationship between the address returned from ioremap and what you pass into io_remap_page_range(). ioremap gives you a kernel virtual address for the PCI address you remap. io_remap_page_range() creates a userspace mapping in the same way, and you should pass in the PCI address exactly the same way you pass in the PCI address into ioremap. io_remap_pfn_range() takes a PFN (page frame number), which is basically the PCI address you want to map divided by PAGE_SIZE. The main reason for using PFNs is that they allow you to map addresses above 4G even if sizeof long is only 4. In your code: dev.pcibar2 = ioremap_nocache(resource,size); dev.region_start = dev.pcibar2 + offset; // RAM is at some offset from base This gives you a kernel mapping that you can use with readl(), writel() etc to access the PCI memory from the kernel. To map to userspace, this: if (io_remap_page_range(vma, phyaddr, vma-vm_start, vsize, vma-vm_page_prot)) should use phyaddr as you have it here: // phyaddr = physical address of PCI memory area This is just wrong: unsigned long phy= __pa(dev-region_start + off); __pa() doesn't work on addresses returned from ioremap. Just use the same resource address you passed into ioremap. - R. - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: Mapping PCI memory to user-space
On 10/24/2007 08:59 AM, joncglenn wrote: > I am writing a driver to map a PCI board memory space (pcibar2) into a > user-space vma via 'mmap'. What is the relationship between the address > returned from ioremap and the type of address needed in the > 'io_remap_page_range' or 'remap_pfn_range' functions? How about the > following? (I am developing under RHEL4 and a 2.6.9 kernel) I think you can use the method used for exporting pci resources in /sys. See pci_mmap_resource. Don't know if this was yet in 2.6.9... regards, -- Jiri Slaby ([EMAIL PROTECTED]) Faculty of Informatics, Masaryk University - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Mapping PCI memory to user-space
I am writing a driver to map a PCI board memory space (pcibar2) into a
user-space vma via 'mmap'. What is the relationship between the address
returned from ioremap and the type of address needed in the
'io_remap_page_range' or 'remap_pfn_range' functions? How about the
following? (I am developing under RHEL4 and a 2.6.9 kernel)
In the 'init' part of the driver:
dev.pcibar2 = ioremap_nocache(resource,size);
dev.region_start = dev.pcibar2 + offset; // RAM is at some offset
from base
dev.region_size =
In the mydriver_mmap function:
static ssize_t mydriver_mmap (struct file *filp,
struct vm_area_struct
*vma)
{
// off = convert vm_pgoff back to user-space mmap 'off' value
// phyaddr = physical address of PCI memory area
// vsize = total size of area user wants to map
// psize = total avail size in device
struct mydriver_dev *dev = filp->private_data;
unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
unsigned long phy= __pa(dev->region_start + off);
unsigned long vsize = vma->vm_end - vma->vm_start;
unsigned long psize = dev->region_size - off;
if (vsize > psize)
return -EINVAL; /* spans too high */
if (io_remap_page_range(vma, phyaddr, vma->vm_start, vsize,
vma->vm_page_prot))
return -EAGAIN;
vma->vm_ops= _vm_ops;
vma->vm_flags |= VM_IO | VM_RESERVED;
mydriver_vma_open(vma);
return 0;
}
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Mapping PCI memory to user-space
I am writing a driver to map a PCI board memory space (pcibar2) into a
user-space vma via 'mmap'. What is the relationship between the address
returned from ioremap and the type of address needed in the
'io_remap_page_range' or 'remap_pfn_range' functions? How about the
following? (I am developing under RHEL4 and a 2.6.9 kernel)
In the 'init' part of the driver:
dev.pcibar2 = ioremap_nocache(resource,size);
dev.region_start = dev.pcibar2 + offset; // RAM is at some offset
from base
dev.region_size = some size
In the mydriver_mmap function:
static ssize_t mydriver_mmap (struct file *filp,
struct vm_area_struct
*vma)
{
// off = convert vm_pgoff back to user-space mmap 'off' value
// phyaddr = physical address of PCI memory area
// vsize = total size of area user wants to map
// psize = total avail size in device
struct mydriver_dev *dev = filp-private_data;
unsigned long off = vma-vm_pgoff PAGE_SHIFT;
unsigned long phy= __pa(dev-region_start + off);
unsigned long vsize = vma-vm_end - vma-vm_start;
unsigned long psize = dev-region_size - off;
if (vsize psize)
return -EINVAL; /* spans too high */
if (io_remap_page_range(vma, phyaddr, vma-vm_start, vsize,
vma-vm_page_prot))
return -EAGAIN;
vma-vm_ops= mydriver_vm_ops;
vma-vm_flags |= VM_IO | VM_RESERVED;
mydriver_vma_open(vma);
return 0;
}
--
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http://www.nabble.com/Mapping-PCI-memory-to-user-space-tf4682416.html#a13380086
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Re: Mapping PCI memory to user-space
On 10/24/2007 08:59 AM, joncglenn wrote: I am writing a driver to map a PCI board memory space (pcibar2) into a user-space vma via 'mmap'. What is the relationship between the address returned from ioremap and the type of address needed in the 'io_remap_page_range' or 'remap_pfn_range' functions? How about the following? (I am developing under RHEL4 and a 2.6.9 kernel) I think you can use the method used for exporting pci resources in /sys. See pci_mmap_resource. Don't know if this was yet in 2.6.9... regards, -- Jiri Slaby ([EMAIL PROTECTED]) Faculty of Informatics, Masaryk University - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
