Untranslated page fault with pgprot_noncached()
up vote
0
down vote
favorite
I use 2 ARM boards for DMA remote write and read.
With SMMU enabled, I faced an issue while fetching the physical address which is required for mapping the physical address to the kernel address in the user space.
Currently, I am experimenting with SMMU disabled.
Here is the flow:
ker_addr = (u64) dma_alloc_coherent (... dma_addr_t bus_addr); // does casting cause any issue?
phys_addr = bus_addr;
mmap (...phys_addr);
vma->vm_page_prot = pgprot_noncached(vma>vm_page_prot);
remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start, vma->vm_page_prot));
But, resulted in untraslated page fault.
When commented pgprot_noncached in the custom driver, I found no error.
Please help me know the cause.
Also, is it recommended to replace remap_pfn_range() with dma_mmap_coherent()?
As far as I know, remap_pfn_range() deals with the physical address where as dma_mmap_coherent() deals with the bus address given by dma_alloc_coherent().
Please let me know if it is different.
Thanks in advance !!
arm dma pci-e
asked Nov 22 at 11:54
PBang
11
add a comment |
up vote
0
down vote
favorite
I use 2 ARM boards for DMA remote write and read.
With SMMU enabled, I faced an issue while fetching the physical address which is required for mapping the physical address to the kernel address in the user space.
Currently, I am experimenting with SMMU disabled.
Here is the flow:
ker_addr = (u64) dma_alloc_coherent (... dma_addr_t bus_addr); // does casting cause any issue?
phys_addr = bus_addr;
mmap (...phys_addr);
vma->vm_page_prot = pgprot_noncached(vma>vm_page_prot);
remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start, vma->vm_page_prot));
But, resulted in untraslated page fault.
When commented pgprot_noncached in the custom driver, I found no error.
Please help me know the cause.
Also, is it recommended to replace remap_pfn_range() with dma_mmap_coherent()?
As far as I know, remap_pfn_range() deals with the physical address where as dma_mmap_coherent() deals with the bus address given by dma_alloc_coherent().
Please let me know if it is different.
Thanks in advance !!
arm dma pci-e
asked Nov 22 at 11:54
PBang
11
Can somebody please comment on this?
– PBang
Nov 26 at 10:04
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I use 2 ARM boards for DMA remote write and read.
With SMMU enabled, I faced an issue while fetching the physical address which is required for mapping the physical address to the kernel address in the user space.
Currently, I am experimenting with SMMU disabled.
Here is the flow:
ker_addr = (u64) dma_alloc_coherent (... dma_addr_t bus_addr); // does casting cause any issue?
phys_addr = bus_addr;
mmap (...phys_addr);
vma->vm_page_prot = pgprot_noncached(vma>vm_page_prot);
remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start, vma->vm_page_prot));
But, resulted in untraslated page fault.
When commented pgprot_noncached in the custom driver, I found no error.
Please help me know the cause.
Also, is it recommended to replace remap_pfn_range() with dma_mmap_coherent()?
As far as I know, remap_pfn_range() deals with the physical address where as dma_mmap_coherent() deals with the bus address given by dma_alloc_coherent().
Please let me know if it is different.
Thanks in advance !!
arm dma pci-e
asked Nov 22 at 11:54
PBang
11
I use 2 ARM boards for DMA remote write and read.
With SMMU enabled, I faced an issue while fetching the physical address which is required for mapping the physical address to the kernel address in the user space.
Currently, I am experimenting with SMMU disabled.
Here is the flow:
ker_addr = (u64) dma_alloc_coherent (... dma_addr_t bus_addr); // does casting cause any issue?
phys_addr = bus_addr;
mmap (...phys_addr);
vma->vm_page_prot = pgprot_noncached(vma>vm_page_prot);
remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
vma->vm_end - vma->vm_start, vma->vm_page_prot));
But, resulted in untraslated page fault.
When commented pgprot_noncached in the custom driver, I found no error.
Please help me know the cause.
Also, is it recommended to replace remap_pfn_range() with dma_mmap_coherent()?
As far as I know, remap_pfn_range() deals with the physical address where as dma_mmap_coherent() deals with the bus address given by dma_alloc_coherent().
Please let me know if it is different.
Thanks in advance !!
arm dma pci-e
arm dma pci-e
asked Nov 22 at 11:54
PBang
11
asked Nov 22 at 11:54
PBang
11
asked Nov 22 at 11:54
PBang
11
asked Nov 22 at 11:54
PBang
11
asked Nov 22 at 11:54
PBang
11
11
Can somebody please comment on this?
– PBang
Nov 26 at 10:04
add a comment |
Can somebody please comment on this?
– PBang
Nov 26 at 10:04
Can somebody please comment on this?
– PBang
Nov 26 at 10:04
Can somebody please comment on this?
– PBang
Nov 26 at 10:04
add a comment |
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
active
oldest
votes
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Some of your past answers have not been well-received, and you're in danger of being blocked from answering.
Please pay close attention to the following guidance:
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53430470%2funtranslated-page-fault-with-pgprot-noncached%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Can somebody please comment on this?
– PBang
Nov 26 at 10:04