Messages in this thread | | | Date | Thu, 28 Sep 2023 11:49:25 +0800 | Subject | Re: [PATCH 1/3] ACPI: PCC: Add PCC shared memory region command and status bitfields | From | "lihuisong (C)" <> |
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在 2023/9/27 21:59, Sudeep Holla 写道: > On Wed, Sep 27, 2023 at 10:07:15AM +0800, lihuisong (C) wrote: >> Hi Sudeep, >> >> 在 2023/9/26 20:28, Sudeep Holla 写道: >>> Define the common macros to use when referring to various bitfields in >>> the PCC generic communications channel command and status fields. >> Can you define the bit0 macros in the "flags" for Extended PCC Subspace >> Shared Memory Region? > Sure I will take a look and include it in v2 if applicable. Thanks > >>> Currently different drivers that need to use these bitfields have defined >>> these locally. This common macro is intended to consolidate and replace >>> those. >>> >>> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> >>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> >>> --- >>> include/acpi/pcc.h | 11 +++++++++++ >>> 1 file changed, 11 insertions(+) >>> >>> diff --git a/include/acpi/pcc.h b/include/acpi/pcc.h >>> index 73e806fe7ce7..66d9934c2ee4 100644 >>> --- a/include/acpi/pcc.h >>> +++ b/include/acpi/pcc.h >>> @@ -18,7 +18,18 @@ struct pcc_mbox_chan { >>> u16 min_turnaround_time; >>> }; >>> +/* Generic Communications Channel Shared Memory Region */ >>> +#define PCC_SIGNATURE 0x50424300 >> Why is this signature 0x50424300? > It is as per the specification. > >> In ACPI spec, this signature is all 0x50434303. > No, not exactly. It is just an example. > The PCC signature - The signature of a subspace is computed by a bitwise-or > of the value 0x50434300 with the subspace ID. For example, subspace 3 has > signature 0x50434303 Sorry for my mistake. I know this. I mean, why doesn't the following macro follow spec and define this signature as 0x504*3*430. "#define PCC_SIGNATURE **0x504*2*4300*"* Because it seems that all version of ACPI spec is 0x5043430. > > And I see the driver you mentioned(drivers/soc/hisilicon/kunpeng_hccs.c) > is doing the right thing. I am bit confused as why you being the author > of the driver are now confused. I used 0x50424300 instead of 0x50424300 according to the spec. >
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