Re: [PATCH v1 2/3] drivers/perf: add DesignWare PCIe PMU driver
From: Robin Murphy
Date: Mon Sep 26 2022 - 11:48:08 EST
On 2022-09-26 14:31, Shuai Xue wrote:
+ Bjorn Helgaas
在 2022/9/23 PM11:54, Jonathan Cameron 写道:
+#define RP_NUM_MAX 32 /* 2die * 4RC * 4Ctrol */
This driver is 'almost' generic. So if you an avoid defines based on a particular
platform that's definitely good!
Good idea. How about defining RP_NUM_MAX as 64? As fars as I know,
some platfrom use 2 sockets, 2 die per socket.
Then 2 sockets * 2 dies * 4 Root Complex * 4 root port.
Setting a reasonable maximum is fine - but make sure the code then fails with
a suitable error message if there are more!
OK, I will add a discovery logic here and count PMU number at runtime.
+#define DWC_PCIE_LANE_SHIFT 4
+#define DWC_PCIE_LANE_MASK GENMASK(9, 4)
+
+#define DWC_PCIE_EVENT_CNT_CTRL 0x8
+#define DWC_PCIE__CNT_EVENT_SELECT_SHIFT 16
Why double __? If point is , then
naming works better
DWC_PCIE_EVENT_CNT_CTRL_REG
DWC_PCIE_EVENT_CNT_CTRL_EV_SELECT_MSK etc
Yes, I point to use double `__` to indicate it is a field of register,
as CMN and CCN drivers do. I also considered naming with REG explicitly,
but the macro is so long that I often have to wrap code into multilines.
Any way, it's fine to rename if you still suggest to do so.
I don't particularly mind. This convention was new to me.
Haha, then I will leave the double `__` as CMN and CCN drivers do.
FWIW I'm not sure there's really any convention. CCN seems to use
double-underscores as distinct separators in a consistent
CCN_REG_NAME__FIELD_NAME__SUFFIX pattern. Conversely in CMN I used it as
an indication of the usual CMN_REG_NAME_FIELD_NAME_VALUE pattern being
abbreviated where it would have been uncomfortably long otherwise (and
particularly where the field name reflects the register name anyway); it
just seemed like a good visual cue to imply that something was missing.
Robin.