On Nov 5, 2013, at 11:35 AM, Stephen Boyd wrote: > On 11/05/13 09:12, Kumar Gala wrote: >> On Nov 4, 2013, at 11:36 AM, Stephen Boyd wrote: >> >>> On 11/01, Rob Herring wrote: >>>> On Fri, Nov 1, 2013 at 5:08 PM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote: >>>>> From: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx> >>>>> >>>>> Scorpion and Krait are Qualcomm cpus. These cpus don't use the >>>>> spin-table enable-method. Instead they rely on mmio register >>>>> accesses to enable power and clocks to bring CPUs out of reset. >>>>> >>>>> Cc: <devicetree@xxxxxxxxxxxxxxx> >>>>> Signed-off-by: Rohit Vaswani <rvaswani@xxxxxxxxxxxxxx> >>>>> [sboyd: Split off into separate patch, renamed method to >>>>> qcom,mmio] >>>>> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> >>>>> --- >>>>> >>>>> This slightly conflicts with my krait EDAC series. >>>>> >>>>> Documentation/devicetree/bindings/arm/cpus.txt | 3 +++ >>>>> 1 file changed, 3 insertions(+) >>>>> >>>>> diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt >>>>> index 37258f9..e2969fa2 100644 >>>>> --- a/Documentation/devicetree/bindings/arm/cpus.txt >>>>> +++ b/Documentation/devicetree/bindings/arm/cpus.txt >>>>> @@ -44,6 +44,8 @@ For the ARM architecture every CPU node must contain the following properties: >>>>> "marvell,mohawk" >>>>> "marvell,xsc3" >>>>> "marvell,xscale" >>>>> + "qcom,scorpion" >>>>> + "qcom,krait" >>>>> >>>>> And the following optional properties: >>>>> >>>>> @@ -52,6 +54,7 @@ And the following optional properties: >>>>> different types of cpus. >>>>> This should be one of: >>>>> "spin-table" >>>>> + "qcom,mmio" >>>> Not exactly specific. How would you handle variations in the enable >>>> method? The mmio method to enable is tied to the core type or SOC >>>> type? >>> Variations in the enable method are handled by searching for >>> another node with different compatible strings. Later on in this >>> series you'll see that we search for gcc-8660, kpss-acc-v1, or >>> kpps-acc-v2. Once we find one of these nodes we perform the >>> correct cold boot routine. >>> >>> I'm actually considering renaming this to "qcom,cold-boot". We >>> could further extend the enable-metho property to allow >>> "qcom,warm-boot" and then for cases like kexec we could make the >>> enable method be warm boot and our smp code could be smart enough >>> to know to skip the whole cold boot sequence. >> >> I think this should be more specific than just 'qcom,mmio' or 'qcom,warm-boot'. It should be 'qcom,kpss-acc-v1' or 'qcom-gcc-8660'. >> > > Do you have any reasons why? I don't see why we need to keep adding more > and more enable-methods every time the subsystem surrounding the CPU > changes. The method is the same, write some registers to power up the > CPU for the first time (cold boot) or ping the CPU to wake it up > (warmboot). The only difference is where those registers live and a > slight variation in the sequence that we perform. By that argument every device could just be compatible with 'mmio' and be done with it ;) As the registers you write vary, the compatible should vary. - k -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
