WDF Dma Transaction Issue
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From: eagersh on 16 Nov 2009 19:46 On Nov 13, 1:04 pm, Murugesan <Muruge...(a)discussions.microsoft.com> wrote: > Sorry Igor, my information might be unclear.I doesn't mean like that. We have > a separate core which follows a vendor specific protocol. Some registers are > there to control this core which is in a separate memory in the h/w & can be > read/write only by using DMA. > We have some registers mapped from PCI space separately which includes DMA > ADDR registers, DMA Control registers. The registers to control the core are > not mapped to PCI space, so slave access to these registers are not possible. > Core regiser read/write can only done through DMA. Now my question is does > framework supports to perform DMA for such > small length? > > Murugesan > If your DMA registers are not mapped to PCI address space how could initiate DMA transaction? It is not matter if you have small or big buffer to transfer. Windows framework only provides MDL or physical memory which you could use for DMA transfer but initiate DMA transaction must be done by your driver. You driver must prepare dma operation and starts it. You could look a sample in WDK - PLX9x5x which shows how a driver does DMA operations. Igor Sharovar
From: Murugesan on 18 Nov 2009 01:10 OK. Actually I have two different sets of registers in my hw. One set of registers are mapped to PCI space which includes DMA ADDR registers, DMA control registers[these registers are used to initiate DMA transaction. Other set of registers are in hw buffer. This register space is completly different and these are not mapped to PCI space. Read/Write to these registers are done using DMA with the DMA control registers. These set of registers are interface independent i.e they can be read/write using PCI[dma]/SDIO. Read/Write to these second set of registers are only possible via DMA[PCI] or CMD53[SDIO]. I hope this would explain my hw design. I've already verified the WDK samples, based on that i've posted some questions in my first post. Coming back to original questions in my first post, 1. Can we perform DMA for 8 bytes using dmatransaction ? YES.[From your previous answer] 2. What is wrong in the above mentioned sequence ? I have provided a pseudo code in my first post. Please get back to my first post. 3. Is it mandatory to call WdfDmaTransactionDmaCompleted in DPC handler ? [ Right now, i've some problem with the interrupt, so only polling mode is used) 4. I haven't initiated DMA on the context of a wdfrequest, so i can't use WdfDmaTransactionInitializeUsingRequest(), will it be an issue ? [ This is because all the sample drivers provided by microsoft has used WdfDmaTransactionInitializeUsingRequest() and DMA has been initiated from EvtIoQueue dispatched by any WdfRequest. Murugesan "eagersh" wrote: > On Nov 13, 1:04 pm, Murugesan <Muruge...(a)discussions.microsoft.com> > wrote: > > Sorry Igor, my information might be unclear.I doesn't mean like that. We have > > a separate core which follows a vendor specific protocol. Some registers are > > there to control this core which is in a separate memory in the h/w & can be > > read/write only by using DMA. > > We have some registers mapped from PCI space separately which includes DMA > > ADDR registers, DMA Control registers. The registers to control the core are > > not mapped to PCI space, so slave access to these registers are not possible. > > Core regiser read/write can only done through DMA. Now my question is does > > framework supports to perform DMA for such > > small length? > > > > Murugesan > > > > If your DMA registers are not mapped to PCI address space how could > initiate DMA transaction? > It is not matter if you have small or big buffer to transfer. Windows > framework only provides MDL or physical memory which you could use for > DMA transfer but initiate DMA transaction must be done by your driver. > You driver must prepare dma operation and starts it. You could look a > sample in WDK - PLX9x5x which shows how a driver does DMA operations. > > Igor Sharovar > . >
From: eagersh on 18 Nov 2009 14:53 On Nov 17, 11:10 pm, Murugesan <Muruge...(a)discussions.microsoft.com> wrote: > OK. Actually I have two different sets of registers in my hw. > One set of registers are mapped to PCI space which includes DMA ADDR > registers, DMA control registers[these registers are used to initiate DMA > transaction. > Other set of registers are in hw buffer. This register space is completly > different and these are not mapped to PCI space. Read/Write to these > registers are done using DMA with the DMA control registers. These set of > registers are interface independent i.e they can be read/write using > PCI[dma]/SDIO. Read/Write to these second set of registers are only possible > via DMA[PCI] or CMD53[SDIO]. > I hope this would explain my hw design. > I've already verified the WDK samples, based on that i've posted some > questions in my first post. > Coming back to original questions in my first post, > > 1. Can we perform DMA for 8 bytes using dmatransaction ? > YES.[From your previous answer] There is only one limitation but it is not from Windows side. You should check what kind of aliment of memory your hardware support. > 2. What is wrong in the above mentioned sequence ? > I have provided a pseudo code in my first post. Please get back to my > first post. Is your ProgramDmaFunction called? If it is, you should show this function too. I have one comments. Usually if you allocate memory and MDL you need to call MmBuildMdlForNonPagedPool. I don't know if this could be related if you allocate a buffer by using MmAllocateContiguousMemory. For 8 bytes buffer you don't need to use MmAllocateContiguousMemory anyway. > 3. Is it mandatory to call WdfDmaTransactionDmaCompleted in DPC handler ? > [ Right now, i've some problem with the interrupt, so only polling mode is > used) No. This function is not linked to interrupt. It is only tells WDF that DMA transaction is complete and ProgramDmaFunction should not be called again. > 4. I haven't initiated DMA on the context of a wdfrequest, so i can't use > WdfDmaTransactionInitializeUsingRequest(), will it be an issue ? [ This is > because all the sample drivers provided by microsoft has used > WdfDmaTransactionInitializeUsingRequest() and DMA has been initiated from > EvtIoQueue dispatched by any WdfRequest. No, it should not be an issue. Igor Sharovar
From: Abhishek R [MSFT] on 19 Nov 2009 01:55 Some suggestions - - Did you call MmProbeAndLockPages() or BuildMdlFromScatterGatherList() for the memory you allocated? If you haven't built the PFN array for the MDL then you won't be able to do DMA to it. - Call WdfDmaTransactionDmaCompleted instead of WdfDmaTransactionDmaCompletedFinal when terminating the transaction. - Check the WDF log for errors (!wdflogdump debugger extension) - Enable driver verifier and WDF verifier on your driver - Try allocating non-cached memory to see if it makes a difference ( MmAllocateContiguousMemorySpecifyCache) - Use h/w analyzers to see if dma transaction actually takes place "Murugesan" <Murugesan(a)discussions.microsoft.com> wrote in message news:37A20A0C-F067-4B9E-950F-C51A4234D301(a)microsoft.com... > OK. Actually I have two different sets of registers in my hw. > One set of registers are mapped to PCI space which includes DMA ADDR > registers, DMA control registers[these registers are used to initiate DMA > transaction. > Other set of registers are in hw buffer. This register space is completly > different and these are not mapped to PCI space. Read/Write to these > registers are done using DMA with the DMA control registers. These set of > registers are interface independent i.e they can be read/write using > PCI[dma]/SDIO. Read/Write to these second set of registers are only > possible > via DMA[PCI] or CMD53[SDIO]. > I hope this would explain my hw design. > I've already verified the WDK samples, based on that i've posted some > questions in my first post. > Coming back to original questions in my first post, > > 1. Can we perform DMA for 8 bytes using dmatransaction ? > YES.[From your previous answer] > > 2. What is wrong in the above mentioned sequence ? > I have provided a pseudo code in my first post. Please get back to my > first post. > > 3. Is it mandatory to call WdfDmaTransactionDmaCompleted in DPC handler ? > [ Right now, i've some problem with the interrupt, so only polling mode is > used) > > 4. I haven't initiated DMA on the context of a wdfrequest, so i can't use > WdfDmaTransactionInitializeUsingRequest(), will it be an issue ? [ This is > because all the sample drivers provided by microsoft has used > WdfDmaTransactionInitializeUsingRequest() and DMA has been initiated from > EvtIoQueue dispatched by any WdfRequest. > > > Murugesan > > > "eagersh" wrote: > >> On Nov 13, 1:04 pm, Murugesan <Muruge...(a)discussions.microsoft.com> >> wrote: >> > Sorry Igor, my information might be unclear.I doesn't mean like that. >> > We have >> > a separate core which follows a vendor specific protocol. Some >> > registers are >> > there to control this core which is in a separate memory in the h/w & >> > can be >> > read/write only by using DMA. >> > We have some registers mapped from PCI space separately which includes >> > DMA >> > ADDR registers, DMA Control registers. The registers to control the >> > core are >> > not mapped to PCI space, so slave access to these registers are not >> > possible. >> > Core regiser read/write can only done through DMA. Now my question is >> > does >> > framework supports to perform DMA for such >> > small length? >> > >> > Murugesan >> > >> >> If your DMA registers are not mapped to PCI address space how could >> initiate DMA transaction? >> It is not matter if you have small or big buffer to transfer. Windows >> framework only provides MDL or physical memory which you could use for >> DMA transfer but initiate DMA transaction must be done by your driver. >> You driver must prepare dma operation and starts it. You could look a >> sample in WDK - PLX9x5x which shows how a driver does DMA operations. >> >> Igor Sharovar >> . >>
From: Murugesan on 23 Nov 2009 02:14
Guys, Thanks for your reply. I think the issue might be the memory to get paged out. From Abishek & Igor's answers I could infer that I've missed to lock the physical pages or to use MmBuildMdlForNonPagedPool. This might be the reason for failure. I'll add corresponding functionalities. Thanks, Murugesan.S "Abhishek R [MSFT]" wrote: > Some suggestions - > - Did you call MmProbeAndLockPages() or BuildMdlFromScatterGatherList() for > the memory you allocated? If you haven't built the PFN array for the MDL > then you won't be able to do DMA to it. > - Call WdfDmaTransactionDmaCompleted instead of > WdfDmaTransactionDmaCompletedFinal when terminating the transaction. > - Check the WDF log for errors (!wdflogdump debugger extension) > - Enable driver verifier and WDF verifier on your driver > - Try allocating non-cached memory to see if it makes a difference ( > MmAllocateContiguousMemorySpecifyCache) > - Use h/w analyzers to see if dma transaction actually takes place > > "Murugesan" <Murugesan(a)discussions.microsoft.com> wrote in message > news:37A20A0C-F067-4B9E-950F-C51A4234D301(a)microsoft.com... > > OK. Actually I have two different sets of registers in my hw. > > One set of registers are mapped to PCI space which includes DMA ADDR > > registers, DMA control registers[these registers are used to initiate DMA > > transaction. > > Other set of registers are in hw buffer. This register space is completly > > different and these are not mapped to PCI space. Read/Write to these > > registers are done using DMA with the DMA control registers. These set of > > registers are interface independent i.e they can be read/write using > > PCI[dma]/SDIO. Read/Write to these second set of registers are only > > possible > > via DMA[PCI] or CMD53[SDIO]. > > I hope this would explain my hw design. > > I've already verified the WDK samples, based on that i've posted some > > questions in my first post. > > Coming back to original questions in my first post, > > > > 1. Can we perform DMA for 8 bytes using dmatransaction ? > > YES.[From your previous answer] > > > > 2. What is wrong in the above mentioned sequence ? > > I have provided a pseudo code in my first post. Please get back to my > > first post. > > > > 3. Is it mandatory to call WdfDmaTransactionDmaCompleted in DPC handler ? > > [ Right now, i've some problem with the interrupt, so only polling mode is > > used) > > > > 4. I haven't initiated DMA on the context of a wdfrequest, so i can't use > > WdfDmaTransactionInitializeUsingRequest(), will it be an issue ? [ This is > > because all the sample drivers provided by microsoft has used > > WdfDmaTransactionInitializeUsingRequest() and DMA has been initiated from > > EvtIoQueue dispatched by any WdfRequest. > > > > > > Murugesan > > > > > > "eagersh" wrote: > > > >> On Nov 13, 1:04 pm, Murugesan <Muruge...(a)discussions.microsoft.com> > >> wrote: > >> > Sorry Igor, my information might be unclear.I doesn't mean like that. > >> > We have > >> > a separate core which follows a vendor specific protocol. Some > >> > registers are > >> > there to control this core which is in a separate memory in the h/w & > >> > can be > >> > read/write only by using DMA. > >> > We have some registers mapped from PCI space separately which includes > >> > DMA > >> > ADDR registers, DMA Control registers. The registers to control the > >> > core are > >> > not mapped to PCI space, so slave access to these registers are not > >> > possible. > >> > Core regiser read/write can only done through DMA. Now my question is > >> > does > >> > framework supports to perform DMA for such > >> > small length? > >> > > >> > Murugesan > >> > > >> > >> If your DMA registers are not mapped to PCI address space how could > >> initiate DMA transaction? > >> It is not matter if you have small or big buffer to transfer. Windows > >> framework only provides MDL or physical memory which you could use for > >> DMA transfer but initiate DMA transaction must be done by your driver. > >> You driver must prepare dma operation and starts it. You could look a > >> sample in WDK - PLX9x5x which shows how a driver does DMA operations. > >> > >> Igor Sharovar > >> . > >> > . > |