Hi Sebastian,

On Wed, Jun 14, 2023 at 03:40:34PM +0200, Sebastian Reichel wrote:

Hi,

On Wed, May 24, 2023 at 10:31:28AM +0200, Sascha Hauer wrote:

quoted

This is v5 of the series adding perf support to the rockchip DFI driver.

A lot has changed in the perf driver since v4. First of all the review
feedback from Robin and Jonathan has been integrated. The perf driver
now not only supports monitoring the total DDR utilization, but also the
individual channels. I also reworked the way the raw 32bit counter
values are summed up to 64bit perf values, so hopefully the code is
easier to follow now.

lockdep found out that that locking in the perf driver was broken, so I
reworked that as well. None of the perf hooks allows locking with
mutexes or spinlocks, so in perf it's not possible to enable the DFI
controller when needed. Instead I now unconditionally enable the DFI
controller during probe when perf is enabled.

Furthermore the hrtimer I use for reading out the hardware counter
values before they overflow race with perf. Now a seqlock is used to
prevent that.

The RK3588 device tree changes for the DFI were not part of v4. As
Vincent Legoll showed interest in testing this series the necessary
device tree changes are now part of this series.

I tested the series on RK3588 EVB1. The read/write byts looks
sensible. Sometimes cycles reads unrealistic values, though:

 Performance counter stats for 'system wide':

18446744070475110400      rockchip_ddr/cycles/

I'll have a look later this day. I remember seeing this, but I thought
this had been resolved already.

Thanks for your feedback so far.

Sascha

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