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@xxxxxxxxx>
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
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.
