| Message ID | 20240508170721.3023-3-ansuelsmth@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | mips: bmips: improve handling of RAC and CBR addr | expand |
On Wed, May 08, 2024 at 07:07:18PM +0200, Christian Marangi wrote: > Document brcm,bmips-cbr-reg property. > > Some SoC suffer from a BUG where read_c0_brcm_cbr() might return 0 > if called from TP1. The CBR address is always the same on the SoC > hence it can be provided in DT to handle broken case where bootloader > doesn't init it or SMP where read_c0_brcm_cbr() returns 0 from TP1. > > Usage of this property is to give an address also in these broken > configuration/bootloader. > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> > --- > .../devicetree/bindings/mips/brcm/soc.yaml | 23 +++++++++++++++++++ > 1 file changed, 23 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mips/brcm/soc.yaml b/Documentation/devicetree/bindings/mips/brcm/soc.yaml > index 975945ca2888..77f73ab48c11 100644 > --- a/Documentation/devicetree/bindings/mips/brcm/soc.yaml > +++ b/Documentation/devicetree/bindings/mips/brcm/soc.yaml > @@ -55,6 +55,15 @@ properties: > under the "cpus" node. > $ref: /schemas/types.yaml#/definitions/uint32 > > + brcm,bmips-cbr-reg: > + description: Reference address of the CBR. Pretty sure that Rob commented last time that there's no definition anywhere here of CBR, but I don't see either a response to him or an explanation in v3 as to what CBR means. > + Some SoC suffer from a BUG where read_c0_brcm_cbr() might > + return 0 if called from TP1. The CBR address is always the > + same on the SoC hence it can be provided in DT to handle > + broken case where bootloader doesn't initialise it or SMP > + where read_c0_brcm_cbr() returns 0 from TP1. Why is a ?linux? function name in the binding? Surely this is just "or in SMP systems where reading CBR returns 0 from...", no? Ditto above. Thanks, Conor. > + $ref: /schemas/types.yaml#/definitions/uint32 > + > patternProperties: > "^cpu@[0-9]$": > type: object > @@ -64,6 +73,20 @@ properties: > required: > - mips-hpt-frequency > > +if: > + properties: > + compatible: > + contains: > + enum: > + - brcm,bcm6358 > + - brcm,bcm6368 > + > +then: > + properties: > + cpus: > + required: > + - brcm,bmips-cbr-reg > + > additionalProperties: true > > examples: > -- > 2.43.0 >
On Wed, May 08, 2024 at 06:14:34PM +0100, Conor Dooley wrote: > On Wed, May 08, 2024 at 07:07:18PM +0200, Christian Marangi wrote: > > Document brcm,bmips-cbr-reg property. > > > > Some SoC suffer from a BUG where read_c0_brcm_cbr() might return 0 > > if called from TP1. The CBR address is always the same on the SoC > > hence it can be provided in DT to handle broken case where bootloader > > doesn't init it or SMP where read_c0_brcm_cbr() returns 0 from TP1. > > > > Usage of this property is to give an address also in these broken > > configuration/bootloader. > > > > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> > > --- > > .../devicetree/bindings/mips/brcm/soc.yaml | 23 +++++++++++++++++++ > > 1 file changed, 23 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/mips/brcm/soc.yaml b/Documentation/devicetree/bindings/mips/brcm/soc.yaml > > index 975945ca2888..77f73ab48c11 100644 > > --- a/Documentation/devicetree/bindings/mips/brcm/soc.yaml > > +++ b/Documentation/devicetree/bindings/mips/brcm/soc.yaml > > @@ -55,6 +55,15 @@ properties: > > under the "cpus" node. > > $ref: /schemas/types.yaml#/definitions/uint32 > > > > + brcm,bmips-cbr-reg: > > + description: Reference address of the CBR. > > Pretty sure that Rob commented last time that there's no definition > anywhere here of CBR, but I don't see either a response to him or an > explanation in v3 as to what CBR means. > Sorry I missed it. > > + Some SoC suffer from a BUG where read_c0_brcm_cbr() might > > + return 0 if called from TP1. The CBR address is always the > > + same on the SoC hence it can be provided in DT to handle > > + broken case where bootloader doesn't initialise it or SMP > > + where read_c0_brcm_cbr() returns 0 from TP1. > > Why is a ?linux? function name in the binding? Surely this is just > "or in SMP systems where reading CBR returns 0 from...", no? Ditto > above. > It's really just a reference to reading c0 register at an offset, that is why I was so specific. Ok I will be more verbose. > > > + $ref: /schemas/types.yaml#/definitions/uint32 > > + > > patternProperties: > > "^cpu@[0-9]$": > > type: object > > @@ -64,6 +73,20 @@ properties: > > required: > > - mips-hpt-frequency > > > > +if: > > + properties: > > + compatible: > > + contains: > > + enum: > > + - brcm,bcm6358 > > + - brcm,bcm6368 > > + > > +then: > > + properties: > > + cpus: > > + required: > > + - brcm,bmips-cbr-reg > > + > > additionalProperties: true > > > > examples: > > -- > > 2.43.0 > >
On 5/8/24 10:17, Christian Marangi wrote: > On Wed, May 08, 2024 at 06:14:34PM +0100, Conor Dooley wrote: >> On Wed, May 08, 2024 at 07:07:18PM +0200, Christian Marangi wrote: >>> Document brcm,bmips-cbr-reg property. >>> >>> Some SoC suffer from a BUG where read_c0_brcm_cbr() might return 0 >>> if called from TP1. The CBR address is always the same on the SoC >>> hence it can be provided in DT to handle broken case where bootloader >>> doesn't init it or SMP where read_c0_brcm_cbr() returns 0 from TP1. >>> >>> Usage of this property is to give an address also in these broken >>> configuration/bootloader. >>> >>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> >>> --- >>> .../devicetree/bindings/mips/brcm/soc.yaml | 23 +++++++++++++++++++ >>> 1 file changed, 23 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/mips/brcm/soc.yaml b/Documentation/devicetree/bindings/mips/brcm/soc.yaml >>> index 975945ca2888..77f73ab48c11 100644 >>> --- a/Documentation/devicetree/bindings/mips/brcm/soc.yaml >>> +++ b/Documentation/devicetree/bindings/mips/brcm/soc.yaml >>> @@ -55,6 +55,15 @@ properties: >>> under the "cpus" node. >>> $ref: /schemas/types.yaml#/definitions/uint32 >>> >>> + brcm,bmips-cbr-reg: >>> + description: Reference address of the CBR. >> >> Pretty sure that Rob commented last time that there's no definition >> anywhere here of CBR, but I don't see either a response to him or an >> explanation in v3 as to what CBR means. >> > > Sorry I missed it. FWIW, CBR mean Core Base Register. It is accessed via co-processor 0, register 22, selector 6 using the MIPS processor's way of adding custom co-processor registers.
diff --git a/Documentation/devicetree/bindings/mips/brcm/soc.yaml b/Documentation/devicetree/bindings/mips/brcm/soc.yaml index 975945ca2888..77f73ab48c11 100644 --- a/Documentation/devicetree/bindings/mips/brcm/soc.yaml +++ b/Documentation/devicetree/bindings/mips/brcm/soc.yaml @@ -55,6 +55,15 @@ properties: under the "cpus" node. $ref: /schemas/types.yaml#/definitions/uint32 + brcm,bmips-cbr-reg: + description: Reference address of the CBR. + Some SoC suffer from a BUG where read_c0_brcm_cbr() might + return 0 if called from TP1. The CBR address is always the + same on the SoC hence it can be provided in DT to handle + broken case where bootloader doesn't initialise it or SMP + where read_c0_brcm_cbr() returns 0 from TP1. + $ref: /schemas/types.yaml#/definitions/uint32 + patternProperties: "^cpu@[0-9]$": type: object @@ -64,6 +73,20 @@ properties: required: - mips-hpt-frequency +if: + properties: + compatible: + contains: + enum: + - brcm,bcm6358 + - brcm,bcm6368 + +then: + properties: + cpus: + required: + - brcm,bmips-cbr-reg + additionalProperties: true examples:
Document brcm,bmips-cbr-reg property. Some SoC suffer from a BUG where read_c0_brcm_cbr() might return 0 if called from TP1. The CBR address is always the same on the SoC hence it can be provided in DT to handle broken case where bootloader doesn't init it or SMP where read_c0_brcm_cbr() returns 0 from TP1. Usage of this property is to give an address also in these broken configuration/bootloader. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- .../devicetree/bindings/mips/brcm/soc.yaml | 23 +++++++++++++++++++ 1 file changed, 23 insertions(+)