Re: How to get the physical page addresses from a kernel virtual address for DMA SG List?
You may want to take a look at the user-mode driver infrastructure patches, which do almost exactly what you're trying to do. Get them from http://www.gelato.unsw.edu.au/cgi-bin/viewcvs.cgi/cvs/kernel/usrdrivers/kernel-2.6.12-rc3/ -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
On Thu, 2005-08-04 at 15:39 +0200, Clemens Koller wrote: > Hello, Dick! > > Thanks for your help so far! > > linux-os (Dick Johnson) wrote: > > > > You are trying to do it backwards. You need to have your driver > > use get_dma_pages() to acquire pages suitable for DMA. Your > > driver then impliments mmap(). > > Okay, I have seen that, too. I've seen that some drivers do it the other > way around as I do, but I still try to follow my idea that the > application allocs the memory and the dma / the driver fills it up. > Or are there fundamental problems I get with my approach which I haven't seen > yet? there are some very funamental problems with that; say the user allocation is only half the page, and he uses the other half of the page for something else. during the DMA some other thread calls fork(). Now the stuff under DMA can't COW of course, so only one half gets it. But.. what to do with the second half of the page? this is just one of the many fine fundamental issues you'll face ;) - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
On Thu, 2005-08-04 at 15:39 +0200, Clemens Koller wrote: > > You are trying to do it backwards. You need to have your driver > > use get_dma_pages() to acquire pages suitable for DMA. Your > > driver then impliments mmap(). > > Okay, I have seen that, too. I've seen that some drivers do it the other > way around as I do, but I still try to follow my idea that the > application allocs the memory and the dma / the driver fills it up. > Or are there fundamental problems I get with my approach which I haven't seen > yet? The driver doing the allocation would probably be easier. Do you mean that the application will do some large malloc and then pass that address to the driver? The driver would then need to map in those pages since most of them would probably not be even allocated yet (no physical memory associated to them). Then there's always the point to prevent abuse by the user. If the driver did the allocation, it would just be easier to control. > > > The user-mode application then mmaps() the dma-able pages into > > its address-space. FYI, the pages may be from anywhere, some > > archs can only DMA to/from memory below 16MB. > > My DMA machine (ppc32, mpc8540 cpu) can do the whole 32bit phys address > space so, that's not an issue here. I guess you don't mind that your driver will be locked to a specific architecture. Or at least one that can handle these requirements. Is this just for a single use? > > > The pages do not have > > to be continuous because you will build a scatter-list for > > the DMA engine and you will mmap() the pages so they are > > contiguous to the user. > > Yes, only virtual space is contigous. The DMA can do nice > sg_lists and chained sg_lists, so, this should not be a problem, > too. > > > Also 400 Megabytes is absurd. > > Why? > Actually I am planning to alloc more than 1.5GByte at once, > lock that down, build a big sg_list for all that memory because > I need to _continously_ feed it with data from the DMA. I get > about 200MBytes/sec and I cannot stop in between! Wow! what a system you must have :-) With a 32 bit address space that really does take a big chunck out of it. Well I guess whatever device this driver is for must be for some specific architecture. -- Steve - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
Hello, Dick! Thanks for your help so far! linux-os (Dick Johnson) wrote: You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). Okay, I have seen that, too. I've seen that some drivers do it the other way around as I do, but I still try to follow my idea that the application allocs the memory and the dma / the driver fills it up. Or are there fundamental problems I get with my approach which I haven't seen yet? The user-mode application then mmaps() the dma-able pages into its address-space. FYI, the pages may be from anywhere, some archs can only DMA to/from memory below 16MB. My DMA machine (ppc32, mpc8540 cpu) can do the whole 32bit phys address space so, that's not an issue here. The pages do not have to be continuous because you will build a scatter-list for the DMA engine and you will mmap() the pages so they are contiguous to the user. Yes, only virtual space is contigous. The DMA can do nice sg_lists and chained sg_lists, so, this should not be a problem, too. Also 400 Megabytes is absurd. Why? Actually I am planning to alloc more than 1.5GByte at once, lock that down, build a big sg_list for all that memory because I need to _continously_ feed it with data from the DMA. I get about 200MBytes/sec and I cannot stop in between! Greets, Clemens On Thu, 4 Aug 2005, Clemens Koller wrote: Hello! This might be an FAQ - I've got several ideas from googling around for days and reading 'Linux Device Drivers' or 'Understanding The Linux Kernel' which are both really good books. However I am not really sure of how to do it on the latest linux-2.6. I am currently working on a dma driver for a ppc32 system. The idea is that a userspace app allocates a big contigous chunk of memory (i.e. 400MBytes, user virtual mem) and tells my dma's char driver via ioctl the pointer to that memory. In the driver I can now use that (void __user *) casted address as a kernel virtual address, right? It's contigous there and I can do a memcpy() to get data to userspace simliar to a copy_to_user(). fine! But I want to setup a scatter/gather DMA list and blow my data directly into the applications physical pages. What's the best way to setup the dma_sg_list? I have checked several things to get the pages and physical addresses but with no real success now: get_user_page() vmalloc_to_page() kvirt_to_bus() (deprecated?) virt_to_phys() virt_to_bus() Or do I need to remap the whole thing before I can get all the pages and physical addresses? remap_page_range() remap_pfn_range() map_user_kiobuf() unmap_kiobuf() Or do I need the direct-io stuff or the block-io? How do I need to alloc the mem in my app? (get_pages()?) How do I need to lock the memory to make sure it's in phys memory? (mlockall()?) Can somebody please put some light on what's _the_ way to do that on the latest 2.6 kernels? I am pretty much confused which functions are current and okay to use to solve my problem. Pointers to some code is also very welcome. But it should be _current_. I've spent already a lot of time reading outdated things. :-( Best regards, Clemens Koller ___ R Imaging Devices Anagramm GmbH Rupert-Mayer-Str. 45/1 81379 Muenchen Germany http://www.anagramm.de Phone: +49-89-741518-50 Fax: +49-89-741518-19 - 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/ Cheers, Dick Johnson Penguin : Linux version 2.6.12 on an i686 machine (5537.79 BogoMips). Warning : 98.36% of all statistics are fiction. . I apologize for the following. I tried to kill it with the above dot : The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to [EMAIL PROTECTED] - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). The user-mode application then mmaps() the dma-able pages into its address-space. FYI, the pages may be from anywhere, some archs can only DMA to/from memory below 16MB. The pages do not have to be continuous because you will build a scatter-list for the DMA engine and you will mmap() the pages so they are contiguous to the user. Also 400 Megabytes is absurd. On Thu, 4 Aug 2005, Clemens Koller wrote: > Hello! > > This might be an FAQ - I've got several ideas from googling > around for days and reading 'Linux Device Drivers' or > 'Understanding The Linux Kernel' which are both really good > books. However I am not really sure of how to do it on the latest > linux-2.6. > > I am currently working on a dma driver for a ppc32 system. > The idea is that a userspace app allocates a big contigous > chunk of memory (i.e. 400MBytes, user virtual mem) and tells > my dma's char driver via ioctl the pointer to that memory. > > In the driver I can now use that (void __user *) casted address > as a kernel virtual address, right? It's contigous there and I can > do a memcpy() to get data to userspace simliar to a copy_to_user(). > fine! > > But I want to setup a scatter/gather DMA list and blow my data > directly into the applications physical pages. > > What's the best way to setup the dma_sg_list? > I have checked several things to get the pages and physical addresses > but with no real success now: > get_user_page() > vmalloc_to_page() > kvirt_to_bus() (deprecated?) > virt_to_phys() > virt_to_bus() > > Or do I need to remap the whole thing before I can get all the pages and > physical addresses? > remap_page_range() > remap_pfn_range() > map_user_kiobuf() > unmap_kiobuf() > > Or do I need the direct-io stuff or the block-io? > How do I need to alloc the mem in my app? (get_pages()?) > How do I need to lock the memory to make sure it's in phys memory? > (mlockall()?) > Can somebody please put some light on what's _the_ way to do that on the > latest 2.6 kernels? I am pretty much confused which functions are current > and okay to use to solve my problem. > Pointers to some code is also very welcome. But it should be _current_. > I've spent already a lot of time reading outdated things. :-( > > Best regards, > > Clemens Koller > ___ > R Imaging Devices > Anagramm GmbH > Rupert-Mayer-Str. 45/1 > 81379 Muenchen > Germany > > http://www.anagramm.de > Phone: +49-89-741518-50 > Fax: +49-89-741518-19 > - > 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/ > Cheers, Dick Johnson Penguin : Linux version 2.6.12 on an i686 machine (5537.79 BogoMips). Warning : 98.36% of all statistics are fiction. . I apologize for the following. I tried to kill it with the above dot : The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to [EMAIL PROTECTED] - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). The user-mode application then mmaps() the dma-able pages into its address-space. FYI, the pages may be from anywhere, some archs can only DMA to/from memory below 16MB. The pages do not have to be continuous because you will build a scatter-list for the DMA engine and you will mmap() the pages so they are contiguous to the user. Also 400 Megabytes is absurd. On Thu, 4 Aug 2005, Clemens Koller wrote: Hello! This might be an FAQ - I've got several ideas from googling around for days and reading 'Linux Device Drivers' or 'Understanding The Linux Kernel' which are both really good books. However I am not really sure of how to do it on the latest linux-2.6. I am currently working on a dma driver for a ppc32 system. The idea is that a userspace app allocates a big contigous chunk of memory (i.e. 400MBytes, user virtual mem) and tells my dma's char driver via ioctl the pointer to that memory. In the driver I can now use that (void __user *) casted address as a kernel virtual address, right? It's contigous there and I can do a memcpy() to get data to userspace simliar to a copy_to_user(). fine! But I want to setup a scatter/gather DMA list and blow my data directly into the applications physical pages. What's the best way to setup the dma_sg_list? I have checked several things to get the pages and physical addresses but with no real success now: get_user_page() vmalloc_to_page() kvirt_to_bus() (deprecated?) virt_to_phys() virt_to_bus() Or do I need to remap the whole thing before I can get all the pages and physical addresses? remap_page_range() remap_pfn_range() map_user_kiobuf() unmap_kiobuf() Or do I need the direct-io stuff or the block-io? How do I need to alloc the mem in my app? (get_pages()?) How do I need to lock the memory to make sure it's in phys memory? (mlockall()?) Can somebody please put some light on what's _the_ way to do that on the latest 2.6 kernels? I am pretty much confused which functions are current and okay to use to solve my problem. Pointers to some code is also very welcome. But it should be _current_. I've spent already a lot of time reading outdated things. :-( Best regards, Clemens Koller ___ RD Imaging Devices Anagramm GmbH Rupert-Mayer-Str. 45/1 81379 Muenchen Germany http://www.anagramm.de Phone: +49-89-741518-50 Fax: +49-89-741518-19 - 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/ Cheers, Dick Johnson Penguin : Linux version 2.6.12 on an i686 machine (5537.79 BogoMips). Warning : 98.36% of all statistics are fiction. . I apologize for the following. I tried to kill it with the above dot : The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to [EMAIL PROTECTED] - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
Hello, Dick! Thanks for your help so far! linux-os (Dick Johnson) wrote: You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). Okay, I have seen that, too. I've seen that some drivers do it the other way around as I do, but I still try to follow my idea that the application allocs the memory and the dma / the driver fills it up. Or are there fundamental problems I get with my approach which I haven't seen yet? The user-mode application then mmaps() the dma-able pages into its address-space. FYI, the pages may be from anywhere, some archs can only DMA to/from memory below 16MB. My DMA machine (ppc32, mpc8540 cpu) can do the whole 32bit phys address space so, that's not an issue here. The pages do not have to be continuous because you will build a scatter-list for the DMA engine and you will mmap() the pages so they are contiguous to the user. Yes, only virtual space is contigous. The DMA can do nice sg_lists and chained sg_lists, so, this should not be a problem, too. Also 400 Megabytes is absurd. Why? Actually I am planning to alloc more than 1.5GByte at once, lock that down, build a big sg_list for all that memory because I need to _continously_ feed it with data from the DMA. I get about 200MBytes/sec and I cannot stop in between! Greets, Clemens On Thu, 4 Aug 2005, Clemens Koller wrote: Hello! This might be an FAQ - I've got several ideas from googling around for days and reading 'Linux Device Drivers' or 'Understanding The Linux Kernel' which are both really good books. However I am not really sure of how to do it on the latest linux-2.6. I am currently working on a dma driver for a ppc32 system. The idea is that a userspace app allocates a big contigous chunk of memory (i.e. 400MBytes, user virtual mem) and tells my dma's char driver via ioctl the pointer to that memory. In the driver I can now use that (void __user *) casted address as a kernel virtual address, right? It's contigous there and I can do a memcpy() to get data to userspace simliar to a copy_to_user(). fine! But I want to setup a scatter/gather DMA list and blow my data directly into the applications physical pages. What's the best way to setup the dma_sg_list? I have checked several things to get the pages and physical addresses but with no real success now: get_user_page() vmalloc_to_page() kvirt_to_bus() (deprecated?) virt_to_phys() virt_to_bus() Or do I need to remap the whole thing before I can get all the pages and physical addresses? remap_page_range() remap_pfn_range() map_user_kiobuf() unmap_kiobuf() Or do I need the direct-io stuff or the block-io? How do I need to alloc the mem in my app? (get_pages()?) How do I need to lock the memory to make sure it's in phys memory? (mlockall()?) Can somebody please put some light on what's _the_ way to do that on the latest 2.6 kernels? I am pretty much confused which functions are current and okay to use to solve my problem. Pointers to some code is also very welcome. But it should be _current_. I've spent already a lot of time reading outdated things. :-( Best regards, Clemens Koller ___ RD Imaging Devices Anagramm GmbH Rupert-Mayer-Str. 45/1 81379 Muenchen Germany http://www.anagramm.de Phone: +49-89-741518-50 Fax: +49-89-741518-19 - 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/ Cheers, Dick Johnson Penguin : Linux version 2.6.12 on an i686 machine (5537.79 BogoMips). Warning : 98.36% of all statistics are fiction. . I apologize for the following. I tried to kill it with the above dot : The information transmitted in this message is confidential and may be privileged. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is prohibited. If you are not the intended recipient, please notify Analogic Corporation immediately - by replying to this message or by sending an email to [EMAIL PROTECTED] - and destroy all copies of this information, including any attachments, without reading or disclosing them. Thank you. - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
On Thu, 2005-08-04 at 15:39 +0200, Clemens Koller wrote: You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). Okay, I have seen that, too. I've seen that some drivers do it the other way around as I do, but I still try to follow my idea that the application allocs the memory and the dma / the driver fills it up. Or are there fundamental problems I get with my approach which I haven't seen yet? The driver doing the allocation would probably be easier. Do you mean that the application will do some large malloc and then pass that address to the driver? The driver would then need to map in those pages since most of them would probably not be even allocated yet (no physical memory associated to them). Then there's always the point to prevent abuse by the user. If the driver did the allocation, it would just be easier to control. The user-mode application then mmaps() the dma-able pages into its address-space. FYI, the pages may be from anywhere, some archs can only DMA to/from memory below 16MB. My DMA machine (ppc32, mpc8540 cpu) can do the whole 32bit phys address space so, that's not an issue here. I guess you don't mind that your driver will be locked to a specific architecture. Or at least one that can handle these requirements. Is this just for a single use? The pages do not have to be continuous because you will build a scatter-list for the DMA engine and you will mmap() the pages so they are contiguous to the user. Yes, only virtual space is contigous. The DMA can do nice sg_lists and chained sg_lists, so, this should not be a problem, too. Also 400 Megabytes is absurd. Why? Actually I am planning to alloc more than 1.5GByte at once, lock that down, build a big sg_list for all that memory because I need to _continously_ feed it with data from the DMA. I get about 200MBytes/sec and I cannot stop in between! Wow! what a system you must have :-) With a 32 bit address space that really does take a big chunck out of it. Well I guess whatever device this driver is for must be for some specific architecture. -- Steve - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
On Thu, 2005-08-04 at 15:39 +0200, Clemens Koller wrote: Hello, Dick! Thanks for your help so far! linux-os (Dick Johnson) wrote: You are trying to do it backwards. You need to have your driver use get_dma_pages() to acquire pages suitable for DMA. Your driver then impliments mmap(). Okay, I have seen that, too. I've seen that some drivers do it the other way around as I do, but I still try to follow my idea that the application allocs the memory and the dma / the driver fills it up. Or are there fundamental problems I get with my approach which I haven't seen yet? there are some very funamental problems with that; say the user allocation is only half the page, and he uses the other half of the page for something else. during the DMA some other thread calls fork(). Now the stuff under DMA can't COW of course, so only one half gets it. But.. what to do with the second half of the page? this is just one of the many fine fundamental issues you'll face ;) - 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: How to get the physical page addresses from a kernel virtual address for DMA SG List?
You may want to take a look at the user-mode driver infrastructure patches, which do almost exactly what you're trying to do. Get them from http://www.gelato.unsw.edu.au/cgi-bin/viewcvs.cgi/cvs/kernel/usrdrivers/kernel-2.6.12-rc3/ -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au The technical we do immediately, the political takes *forever* - 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/
