| Message ID | 1538139715-24406-2-git-send-email-pierre-yves.mordret@st.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Add-DMA-MDMA-chaining-support | expand |
On 28-09-18, 15:01, Pierre-Yves MORDRET wrote: > From: M'boumba Cedric Madianga <cedric.madianga@gmail.com> > > This patch adds dma bindings to support DMA/MDMA chaining transfer. > 1 bit is to manage both DMA FIFO Threshold > 1 bit is to manage DMA/MDMA Chaining features. > 2 bits are used to specify SDRAM size to use for DMA/MDMA chaining. Please do mention which specific bits? > The size in bytes of a certain order is given by the formula: > (2 ^ order) * PAGE_SIZE. > The order is given by those 2 bits. > For cyclic, whether chaining is chosen, any value above 1 can be set : > SRAM buffer size will rely on period size and not on this DT value. > > Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> > --- > Version history: > v3: > v2: > * rework content > v1: > * Initial > --- > --- > .../devicetree/bindings/dma/stm32-dma.txt | 27 +++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/dma/stm32-dma.txt b/Documentation/devicetree/bindings/dma/stm32-dma.txt > index c5f5190..2bac8c7 100644 > --- a/Documentation/devicetree/bindings/dma/stm32-dma.txt > +++ b/Documentation/devicetree/bindings/dma/stm32-dma.txt > @@ -17,6 +17,12 @@ Optional properties: > - resets: Reference to a reset controller asserting the DMA controller > - st,mem2mem: boolean; if defined, it indicates that the controller supports > memory-to-memory transfer > +- dmas: A list of eight dma specifiers, one for each entry in dma-names. > + Refer to stm32-mdma.txt for more details. > +- dma-names: should contain "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6" and > + "ch7" and represents each STM32 DMA channel connected to a STM32 MDMA one. > +- memory-region : phandle to a node describing memory to be used for > + M2M intermediate transfer between DMA and MDMA. > > Example: > > @@ -36,6 +42,16 @@ Example: > st,mem2mem; > resets = <&rcc 150>; > dma-requests = <8>; > + dmas = <&mdma1 8 0x10 0x1200000a 0x40026408 0x00000020 1>, > + <&mdma1 9 0x10 0x1200000a 0x40026408 0x00000800 1>, > + <&mdma1 10 0x10 0x1200000a 0x40026408 0x00200000 1>, > + <&mdma1 11 0x10 0x1200000a 0x40026408 0x08000000 1>, > + <&mdma1 12 0x10 0x1200000a 0x4002640C 0x00000020 1>, > + <&mdma1 13 0x10 0x1200000a 0x4002640C 0x00000800 1>, > + <&mdma1 14 0x10 0x1200000a 0x4002640C 0x00200000 1>, > + <&mdma1 15 0x10 0x1200000a 0x4002640C 0x08000000 1>; > + dma-names = "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6", "ch7"; > + memory-region = <&sram_dmapool>; > }; > > * DMA client > @@ -68,7 +84,16 @@ channel: a phandle to the DMA controller plus the following four integer cells: > 0x1: 1/2 full FIFO > 0x2: 3/4 full FIFO > 0x3: full FIFO > - > + -bit 2: Intermediate M2M transfer from/to DDR to/from SRAM throughout MDMA > + 0: MDMA not used to generate an intermediate M2M transfer > + 1: MDMA used to generate an intermediate M2M transfer. > + -bit 3-4: indicated SRAM Buffer size in (2^order)*PAGE_SIZE. > + PAGE_SIZE is given by Linux at 4KiB: include/asm-generic/page.h. > + Order is given by those 2 bits starting at 0. > + Valid only whether Intermediate M2M transfer is set. why do we need this as a property? > + For cyclic, whether Intermediate M2M transfer is chosen, any value can > + be set: SRAM buffer size will rely on period size and not on this DT > + value. > > Example: > > -- > 2.7.4
Hi Vinod On 10/07/2018 04:57 PM, Vinod wrote: > On 28-09-18, 15:01, Pierre-Yves MORDRET wrote: >> From: M'boumba Cedric Madianga <cedric.madianga@gmail.com> >> >> This patch adds dma bindings to support DMA/MDMA chaining transfer. >> 1 bit is to manage both DMA FIFO Threshold >> 1 bit is to manage DMA/MDMA Chaining features. >> 2 bits are used to specify SDRAM size to use for DMA/MDMA chaining. > > Please do mention which specific bits? This is written below into DMA Client section. But I can put some words here. > >> The size in bytes of a certain order is given by the formula: >> (2 ^ order) * PAGE_SIZE. >> The order is given by those 2 bits. >> For cyclic, whether chaining is chosen, any value above 1 can be set : >> SRAM buffer size will rely on period size and not on this DT value. >> >> Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> >> --- >> Version history: >> v3: >> v2: >> * rework content >> v1: >> * Initial >> --- >> --- >> .../devicetree/bindings/dma/stm32-dma.txt | 27 +++++++++++++++++++++- >> 1 file changed, 26 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/devicetree/bindings/dma/stm32-dma.txt b/Documentation/devicetree/bindings/dma/stm32-dma.txt >> index c5f5190..2bac8c7 100644 >> --- a/Documentation/devicetree/bindings/dma/stm32-dma.txt >> +++ b/Documentation/devicetree/bindings/dma/stm32-dma.txt >> @@ -17,6 +17,12 @@ Optional properties: >> - resets: Reference to a reset controller asserting the DMA controller >> - st,mem2mem: boolean; if defined, it indicates that the controller supports >> memory-to-memory transfer >> +- dmas: A list of eight dma specifiers, one for each entry in dma-names. >> + Refer to stm32-mdma.txt for more details. >> +- dma-names: should contain "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6" and >> + "ch7" and represents each STM32 DMA channel connected to a STM32 MDMA one. >> +- memory-region : phandle to a node describing memory to be used for >> + M2M intermediate transfer between DMA and MDMA. >> >> Example: >> >> @@ -36,6 +42,16 @@ Example: >> st,mem2mem; >> resets = <&rcc 150>; >> dma-requests = <8>; >> + dmas = <&mdma1 8 0x10 0x1200000a 0x40026408 0x00000020 1>, >> + <&mdma1 9 0x10 0x1200000a 0x40026408 0x00000800 1>, >> + <&mdma1 10 0x10 0x1200000a 0x40026408 0x00200000 1>, >> + <&mdma1 11 0x10 0x1200000a 0x40026408 0x08000000 1>, >> + <&mdma1 12 0x10 0x1200000a 0x4002640C 0x00000020 1>, >> + <&mdma1 13 0x10 0x1200000a 0x4002640C 0x00000800 1>, >> + <&mdma1 14 0x10 0x1200000a 0x4002640C 0x00200000 1>, >> + <&mdma1 15 0x10 0x1200000a 0x4002640C 0x08000000 1>; >> + dma-names = "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6", "ch7"; >> + memory-region = <&sram_dmapool>; >> }; >> >> * DMA client >> @@ -68,7 +84,16 @@ channel: a phandle to the DMA controller plus the following four integer cells: >> 0x1: 1/2 full FIFO >> 0x2: 3/4 full FIFO >> 0x3: full FIFO >> - >> + -bit 2: Intermediate M2M transfer from/to DDR to/from SRAM throughout MDMA >> + 0: MDMA not used to generate an intermediate M2M transfer >> + 1: MDMA used to generate an intermediate M2M transfer. >> + -bit 3-4: indicated SRAM Buffer size in (2^order)*PAGE_SIZE. >> + PAGE_SIZE is given by Linux at 4KiB: include/asm-generic/page.h. >> + Order is given by those 2 bits starting at 0. >> + Valid only whether Intermediate M2M transfer is set. > > why do we need this as a property? In some UC, we need more than 4KiB in case of chaining for better performances. Chaining has to be enabled by client if performance is at sacks. > >> + For cyclic, whether Intermediate M2M transfer is chosen, any value can >> + be set: SRAM buffer size will rely on period size and not on this DT >> + value. >> >> Example: >> >> -- >> 2.7.4 >
Hi Pierre, On 09-10-18, 09:18, Pierre Yves MORDRET wrote: > >> * DMA client > >> @@ -68,7 +84,16 @@ channel: a phandle to the DMA controller plus the following four integer cells: > >> 0x1: 1/2 full FIFO > >> 0x2: 3/4 full FIFO > >> 0x3: full FIFO > >> - > >> + -bit 2: Intermediate M2M transfer from/to DDR to/from SRAM throughout MDMA > >> + 0: MDMA not used to generate an intermediate M2M transfer > >> + 1: MDMA used to generate an intermediate M2M transfer. > >> + -bit 3-4: indicated SRAM Buffer size in (2^order)*PAGE_SIZE. > >> + PAGE_SIZE is given by Linux at 4KiB: include/asm-generic/page.h. > >> + Order is given by those 2 bits starting at 0. > >> + Valid only whether Intermediate M2M transfer is set. > > > > why do we need this as a property? > > In some UC, we need more than 4KiB in case of chaining for better performances. > Chaining has to be enabled by client if performance is at sacks. Okay if that is the case why is the user not taking care of this? Creating DMA txn and chaining them up and starting the chain? Why would dmaengine driver need to do that?
On 10/09/2018 10:57 AM, Vinod wrote: > Hi Pierre, > > On 09-10-18, 09:18, Pierre Yves MORDRET wrote: > >>>> * DMA client >>>> @@ -68,7 +84,16 @@ channel: a phandle to the DMA controller plus the following four integer cells: >>>> 0x1: 1/2 full FIFO >>>> 0x2: 3/4 full FIFO >>>> 0x3: full FIFO >>>> - >>>> + -bit 2: Intermediate M2M transfer from/to DDR to/from SRAM throughout MDMA >>>> + 0: MDMA not used to generate an intermediate M2M transfer >>>> + 1: MDMA used to generate an intermediate M2M transfer. >>>> + -bit 3-4: indicated SRAM Buffer size in (2^order)*PAGE_SIZE. >>>> + PAGE_SIZE is given by Linux at 4KiB: include/asm-generic/page.h. >>>> + Order is given by those 2 bits starting at 0. >>>> + Valid only whether Intermediate M2M transfer is set. >>> >>> why do we need this as a property? >> >> In some UC, we need more than 4KiB in case of chaining for better performances. >> Chaining has to be enabled by client if performance is at sacks. > > Okay if that is the case why is the user not taking care of this? > Creating DMA txn and chaining them up and starting the chain? Why would > dmaengine driver need to do that? > User is using standard DMA API (single, sg or cyclic) and is agnostic on what is behind the scene(almost). As driver I just fulfill the request to transfer what he wants. My driver scatters transfer into SDRAM chunks defined by user. Unfortunately all transfer are not % the SDRAM size given in DT. This very last txn is to flush the last expected bytes. Whatever user set for chaining(bit 2) the DMA API remains the same at its side.
On Fri, Sep 28, 2018 at 03:01:49PM +0200, Pierre-Yves MORDRET wrote: > From: M'boumba Cedric Madianga <cedric.madianga@gmail.com> > > This patch adds dma bindings to support DMA/MDMA chaining transfer. > 1 bit is to manage both DMA FIFO Threshold > 1 bit is to manage DMA/MDMA Chaining features. > 2 bits are used to specify SDRAM size to use for DMA/MDMA chaining. > The size in bytes of a certain order is given by the formula: > (2 ^ order) * PAGE_SIZE. > The order is given by those 2 bits. > For cyclic, whether chaining is chosen, any value above 1 can be set : > SRAM buffer size will rely on period size and not on this DT value. > > Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com> Missing author S-o-b. > --- > Version history: > v3: > v2: > * rework content > v1: > * Initial > --- > --- > .../devicetree/bindings/dma/stm32-dma.txt | 27 +++++++++++++++++++++- > 1 file changed, 26 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/dma/stm32-dma.txt b/Documentation/devicetree/bindings/dma/stm32-dma.txt index c5f5190..2bac8c7 100644 --- a/Documentation/devicetree/bindings/dma/stm32-dma.txt +++ b/Documentation/devicetree/bindings/dma/stm32-dma.txt @@ -17,6 +17,12 @@ Optional properties: - resets: Reference to a reset controller asserting the DMA controller - st,mem2mem: boolean; if defined, it indicates that the controller supports memory-to-memory transfer +- dmas: A list of eight dma specifiers, one for each entry in dma-names. + Refer to stm32-mdma.txt for more details. +- dma-names: should contain "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6" and + "ch7" and represents each STM32 DMA channel connected to a STM32 MDMA one. +- memory-region : phandle to a node describing memory to be used for + M2M intermediate transfer between DMA and MDMA. Example: @@ -36,6 +42,16 @@ Example: st,mem2mem; resets = <&rcc 150>; dma-requests = <8>; + dmas = <&mdma1 8 0x10 0x1200000a 0x40026408 0x00000020 1>, + <&mdma1 9 0x10 0x1200000a 0x40026408 0x00000800 1>, + <&mdma1 10 0x10 0x1200000a 0x40026408 0x00200000 1>, + <&mdma1 11 0x10 0x1200000a 0x40026408 0x08000000 1>, + <&mdma1 12 0x10 0x1200000a 0x4002640C 0x00000020 1>, + <&mdma1 13 0x10 0x1200000a 0x4002640C 0x00000800 1>, + <&mdma1 14 0x10 0x1200000a 0x4002640C 0x00200000 1>, + <&mdma1 15 0x10 0x1200000a 0x4002640C 0x08000000 1>; + dma-names = "ch0", "ch1", "ch2", "ch3", "ch4", "ch5", "ch6", "ch7"; + memory-region = <&sram_dmapool>; }; * DMA client @@ -68,7 +84,16 @@ channel: a phandle to the DMA controller plus the following four integer cells: 0x1: 1/2 full FIFO 0x2: 3/4 full FIFO 0x3: full FIFO - + -bit 2: Intermediate M2M transfer from/to DDR to/from SRAM throughout MDMA + 0: MDMA not used to generate an intermediate M2M transfer + 1: MDMA used to generate an intermediate M2M transfer. + -bit 3-4: indicated SRAM Buffer size in (2^order)*PAGE_SIZE. + PAGE_SIZE is given by Linux at 4KiB: include/asm-generic/page.h. + Order is given by those 2 bits starting at 0. + Valid only whether Intermediate M2M transfer is set. + For cyclic, whether Intermediate M2M transfer is chosen, any value can + be set: SRAM buffer size will rely on period size and not on this DT + value. Example: