| Message ID | 20220808074051.44736-2-patrice.chotard@foss.st.com |
|---|---|
| State | New |
| Headers | show |
| Series | spi: stm32_qspi: use QSPI bus as 8 lines communication channel | expand |
On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: > From: Patrice Chotard <patrice.chotard@foss.st.com> > > Add new property st,dual-flash which allows to use the QSPI interface as a > communication channel using up to 8 qspi line. > This mode can only be used if cs-gpios property is defined. > > Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> > --- > Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml > index 6ec6f556182f..5e4f9109799e 100644 > --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml > +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml > @@ -46,6 +46,14 @@ properties: > - const: tx > - const: rx > > + st,dual-flash: > + type: boolean > + description: > + Allows to use 8 data lines in case cs-gpios property is defined. It's named dual-flash, but what if you want to use QSPI to connect for example to FPGA? Also how is this related to parallel-memories property? Best regards, Krzysztof
Hi Krzystof On 8/8/22 11:01, Krzysztof Kozlowski wrote: > On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >> From: Patrice Chotard <patrice.chotard@foss.st.com> >> >> Add new property st,dual-flash which allows to use the QSPI interface as a >> communication channel using up to 8 qspi line. >> This mode can only be used if cs-gpios property is defined. >> >> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >> --- >> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >> 1 file changed, 8 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >> index 6ec6f556182f..5e4f9109799e 100644 >> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >> @@ -46,6 +46,14 @@ properties: >> - const: tx >> - const: rx >> >> + st,dual-flash: >> + type: boolean >> + description: >> + Allows to use 8 data lines in case cs-gpios property is defined. > > It's named dual-flash, but what if you want to use QSPI to connect for > example to FPGA? > > Also how is this related to parallel-memories property? I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) which allows to use the 8 lines simultaneously of our dual QSPI block. Best regards Patrice > > Best regards, > Krzysztof
On 08/08/2022 19:08, Patrice CHOTARD wrote: > Hi Krzystof > > On 8/8/22 11:01, Krzysztof Kozlowski wrote: >> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >>> From: Patrice Chotard <patrice.chotard@foss.st.com> >>> >>> Add new property st,dual-flash which allows to use the QSPI interface as a >>> communication channel using up to 8 qspi line. >>> This mode can only be used if cs-gpios property is defined. >>> >>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >>> --- >>> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >>> 1 file changed, 8 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>> index 6ec6f556182f..5e4f9109799e 100644 >>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>> @@ -46,6 +46,14 @@ properties: >>> - const: tx >>> - const: rx >>> >>> + st,dual-flash: >>> + type: boolean >>> + description: >>> + Allows to use 8 data lines in case cs-gpios property is defined. >> >> It's named dual-flash, but what if you want to use QSPI to connect for >> example to FPGA? >> >> Also how is this related to parallel-memories property? > > I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) > which allows to use the 8 lines simultaneously of our dual QSPI block. And how is it related to existing parallel-memories property? Best regards, Krzysztof
On 09/08/2022 07:18, Krzysztof Kozlowski wrote: > On 08/08/2022 19:08, Patrice CHOTARD wrote: >> Hi Krzystof >> >> On 8/8/22 11:01, Krzysztof Kozlowski wrote: >>> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >>>> From: Patrice Chotard <patrice.chotard@foss.st.com> >>>> >>>> Add new property st,dual-flash which allows to use the QSPI interface as a >>>> communication channel using up to 8 qspi line. >>>> This mode can only be used if cs-gpios property is defined. >>>> >>>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >>>> --- >>>> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >>>> 1 file changed, 8 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>> index 6ec6f556182f..5e4f9109799e 100644 >>>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>> @@ -46,6 +46,14 @@ properties: >>>> - const: tx >>>> - const: rx >>>> >>>> + st,dual-flash: >>>> + type: boolean >>>> + description: >>>> + Allows to use 8 data lines in case cs-gpios property is defined. >>> >>> It's named dual-flash, but what if you want to use QSPI to connect for >>> example to FPGA? >>> >>> Also how is this related to parallel-memories property? >> >> I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) >> which allows to use the 8 lines simultaneously of our dual QSPI block. > > And how is it related to existing parallel-memories property? Maybe I was not specific enough, so let me rephrase - we have already parallel-memories property. How this one is different (to justify the new property)? Is just one memory connected in your case to QSPI over 8 data lines? Best regards, Krzysztof
Hi Krzystof On 8/9/22 07:29, Krzysztof Kozlowski wrote: > On 09/08/2022 07:18, Krzysztof Kozlowski wrote: >> On 08/08/2022 19:08, Patrice CHOTARD wrote: >>> Hi Krzystof >>> >>> On 8/8/22 11:01, Krzysztof Kozlowski wrote: >>>> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >>>>> From: Patrice Chotard <patrice.chotard@foss.st.com> >>>>> >>>>> Add new property st,dual-flash which allows to use the QSPI interface as a >>>>> communication channel using up to 8 qspi line. >>>>> This mode can only be used if cs-gpios property is defined. >>>>> >>>>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >>>>> --- >>>>> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >>>>> 1 file changed, 8 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>> index 6ec6f556182f..5e4f9109799e 100644 >>>>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>> @@ -46,6 +46,14 @@ properties: >>>>> - const: tx >>>>> - const: rx >>>>> >>>>> + st,dual-flash: >>>>> + type: boolean >>>>> + description: >>>>> + Allows to use 8 data lines in case cs-gpios property is defined. >>>> >>>> It's named dual-flash, but what if you want to use QSPI to connect for >>>> example to FPGA? >>>> >>>> Also how is this related to parallel-memories property? >>> >>> I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) >>> which allows to use the 8 lines simultaneously of our dual QSPI block. >> >> And how is it related to existing parallel-memories property? > > Maybe I was not specific enough, so let me rephrase - we have already > parallel-memories property. How this one is different (to justify the > new property)? Is just one memory connected in your case to QSPI over 8 > data lines? Our QSPI block is a dual Quad-SPI memory interface, it can managed 2 QSPI flashes independently. There is a specific mode, dual flash mode, where the 2 QSPI flashes can be accessed simultaneously using 8 data lines. In this case, both throughput and capacity are two fold with this mode. To illustrate, you can have a look at STM32MP157 reference manual (chapter 27.3.1 figure 172) available here: https://www.st.com/resource/en/reference_manual/rm0436-stm32mp157-advanced-armbased-32bit-mpus-stmicroelectronics.pdf As you mentioned above, the goal is to connect a FPGA to this 8 lines bus. Hope it clarifies enough ;-) Thanks Patrice > > Best regards, > Krzysztof
On 09/08/2022 10:52, Patrice CHOTARD wrote: > Hi Krzystof > > On 8/9/22 07:29, Krzysztof Kozlowski wrote: >> On 09/08/2022 07:18, Krzysztof Kozlowski wrote: >>> On 08/08/2022 19:08, Patrice CHOTARD wrote: >>>> Hi Krzystof >>>> >>>> On 8/8/22 11:01, Krzysztof Kozlowski wrote: >>>>> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >>>>>> From: Patrice Chotard <patrice.chotard@foss.st.com> >>>>>> >>>>>> Add new property st,dual-flash which allows to use the QSPI interface as a >>>>>> communication channel using up to 8 qspi line. >>>>>> This mode can only be used if cs-gpios property is defined. >>>>>> >>>>>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >>>>>> --- >>>>>> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >>>>>> 1 file changed, 8 insertions(+) >>>>>> >>>>>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>> index 6ec6f556182f..5e4f9109799e 100644 >>>>>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>> @@ -46,6 +46,14 @@ properties: >>>>>> - const: tx >>>>>> - const: rx >>>>>> >>>>>> + st,dual-flash: >>>>>> + type: boolean >>>>>> + description: >>>>>> + Allows to use 8 data lines in case cs-gpios property is defined. >>>>> >>>>> It's named dual-flash, but what if you want to use QSPI to connect for >>>>> example to FPGA? >>>>> >>>>> Also how is this related to parallel-memories property? >>>> >>>> I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) >>>> which allows to use the 8 lines simultaneously of our dual QSPI block. >>> >>> And how is it related to existing parallel-memories property? >> >> Maybe I was not specific enough, so let me rephrase - we have already >> parallel-memories property. How this one is different (to justify the >> new property)? Is just one memory connected in your case to QSPI over 8 >> data lines? > > Our QSPI block is a dual Quad-SPI memory interface, it can managed 2 QSPI flashes independently. > There is a specific mode, dual flash mode, where the 2 QSPI flashes can be accessed simultaneously > using 8 data lines. In this case, both throughput and capacity are two fold with this mode. > > To illustrate, you can have a look at STM32MP157 reference manual (chapter 27.3.1 figure 172) available here: > https://www.st.com/resource/en/reference_manual/rm0436-stm32mp157-advanced-armbased-32bit-mpus-stmicroelectronics.pdf > > As you mentioned above, the goal is to connect a FPGA to this 8 lines bus. > > Hope it clarifies enough ;-) Only partially. Based on the explanation above, it looks like you want to use existing parallel-memories property. Please use that one, instead of adding a new property for the same feature. Best regards, Krzysztof
On 8/9/22 09:57, Krzysztof Kozlowski wrote: > On 09/08/2022 10:52, Patrice CHOTARD wrote: >> Hi Krzystof >> >> On 8/9/22 07:29, Krzysztof Kozlowski wrote: >>> On 09/08/2022 07:18, Krzysztof Kozlowski wrote: >>>> On 08/08/2022 19:08, Patrice CHOTARD wrote: >>>>> Hi Krzystof >>>>> >>>>> On 8/8/22 11:01, Krzysztof Kozlowski wrote: >>>>>> On 08/08/2022 10:40, patrice.chotard@foss.st.com wrote: >>>>>>> From: Patrice Chotard <patrice.chotard@foss.st.com> >>>>>>> >>>>>>> Add new property st,dual-flash which allows to use the QSPI interface as a >>>>>>> communication channel using up to 8 qspi line. >>>>>>> This mode can only be used if cs-gpios property is defined. >>>>>>> >>>>>>> Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com> >>>>>>> --- >>>>>>> Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml | 8 ++++++++ >>>>>>> 1 file changed, 8 insertions(+) >>>>>>> >>>>>>> diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>>> index 6ec6f556182f..5e4f9109799e 100644 >>>>>>> --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>>> +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml >>>>>>> @@ -46,6 +46,14 @@ properties: >>>>>>> - const: tx >>>>>>> - const: rx >>>>>>> >>>>>>> + st,dual-flash: >>>>>>> + type: boolean >>>>>>> + description: >>>>>>> + Allows to use 8 data lines in case cs-gpios property is defined. >>>>>> >>>>>> It's named dual-flash, but what if you want to use QSPI to connect for >>>>>> example to FPGA? >>>>>> >>>>>> Also how is this related to parallel-memories property? >>>>> >>>>> I called it "dual-flash" simply because it enable the dual flash feature of the QSPI block (bit CR_DFM : Dual Flash Mode) >>>>> which allows to use the 8 lines simultaneously of our dual QSPI block. >>>> >>>> And how is it related to existing parallel-memories property? >>> >>> Maybe I was not specific enough, so let me rephrase - we have already >>> parallel-memories property. How this one is different (to justify the >>> new property)? Is just one memory connected in your case to QSPI over 8 >>> data lines? >> >> Our QSPI block is a dual Quad-SPI memory interface, it can managed 2 QSPI flashes independently. >> There is a specific mode, dual flash mode, where the 2 QSPI flashes can be accessed simultaneously >> using 8 data lines. In this case, both throughput and capacity are two fold with this mode. >> >> To illustrate, you can have a look at STM32MP157 reference manual (chapter 27.3.1 figure 172) available here: >> https://www.st.com/resource/en/reference_manual/rm0436-stm32mp157-advanced-armbased-32bit-mpus-stmicroelectronics.pdf >> >> As you mentioned above, the goal is to connect a FPGA to this 8 lines bus. >> >> Hope it clarifies enough ;-) > > Only partially. Based on the explanation above, it looks like you want > to use existing parallel-memories property. Please use that one, instead > of adding a new property for the same feature. Okay, got it, i didn't notice the parallel-memories property recently added. Thanks for pointing it. Patrice > > Best regards, > Krzysztof
diff --git a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml index 6ec6f556182f..5e4f9109799e 100644 --- a/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml +++ b/Documentation/devicetree/bindings/spi/st,stm32-qspi.yaml @@ -46,6 +46,14 @@ properties: - const: tx - const: rx + st,dual-flash: + type: boolean + description: + Allows to use 8 data lines in case cs-gpios property is defined. + +dependencies: + st,dual-flash: [ cs-gpios ] + required: - compatible - reg