Complementing PTT functions

patch 1:
From 60ab0114a9533d8181c381633a16d1612bd49f4e Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Fri, 31 Mar 2023 14:05:12 +0800
Subject: [PATCH 1/5] hwtracing: hisi_ptt: Factor out filter allocation and
 release operation

Factor out the allocation and release of filters. This will make it easier
to extend and manage the function of the filter.

patch 2:
From d6574cff3915fc6c8ddbe9e802aaf6c55458209c Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Tue, 11 Apr 2023 11:54:45 +0800
Subject: [PATCH 2/5] hwtracing: hisi_ptt: Add support for dynamically updating
 the filter list

The PCIe devices supported by the PTT trace can be removed/rescanned by
hotplug or through sysfs.  Add support for dynamically updating the
available filter list by registering a PCI bus notifier block. Then user
can always get latest information about available tracing filters and
driver can block the invalid filters of which related devices no longer
exist in the system.

patch 3:
From 25ae6e1f2d62f781bde4ffc9aaea4dbf80b73baa Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Tue, 11 Apr 2023 11:58:55 +0800
Subject: [PATCH 3/5] hwtracing: hisi_ptt: Export available filters through
 sysfs

The PTT can only filter the traced TLP headers by the Root Ports or the
Requester ID of the Endpoint, which are located on the same PCIe core of
the PTT device. The filter value used is derived from the BDF number of
the supported Root Port or the Endpoint. It's not friendly enough for the
users since it requires the user to be familiar enough with the platform
and calculate the filter value manually.

This patch export the available filters through sysfs. Each available
filters is presented as an individual file with the name of the BDF
number of the related PCIe device. The files are created under
$(PTT PMU dir)/available_root_port_filters and
$(PTT PMU dir)/available_requester_filters respectively. The filter
value can be known by reading the related file.

Then the users can easily know the available filters for trace and get
the filter values without calculating.

patch 4:
From 480da5e8c8b2d9ae34591ae3055a21ae89b008de Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Wed, 22 Feb 2023 14:30:26 +0800
Subject: [PATCH 4/5] hwtracing: hisi_ptt: Advertise PERF_PMU_CAP_NO_EXCLUDE
 for PTT PMU

The PTT trace collects PCIe TLP headers from the PCIe link and don't
have the ability to exclude certain context. It doesn't support itrace
as well. So only advertise PERF_PMU_CAP_NO_EXCLUDE. This will greatly
save the storage of final data. Tested tracing idle link for ~15s,
without this patch we'll collect ~28.682MB data for context related
information and with this patch it reduced to ~0.226MB.

patch 5:
From 2cf91daea11e1f5c2ba0ce187a156fcfadbcf2d1 Mon Sep 17 00:00:00 2001
From: Yicong Yang <yangyicong@hisilicon.com>
Date: Thu, 1 Jun 2023 16:47:10 +0800
Subject: [PATCH 5/5] hwtracing: hisi_ptt: Fix potential sleep in atomic
 context

We're using pci_irq_vector() to obtain the interrupt number and then
bind it to the CPU start perf under the protection of spinlock in
pmu::start(). pci_irq_vector() might sleep since [1] because it will
call msi_domain_get_virq() to get the MSI interrupt number and it
needs to acquire dev->msi.data->mutex. Getting a mutex will sleep on
contention. So use pci_irq_vector() in an atomic context is problematic.

This patch cached the interrupt number in the probe() and uses the
cached data instead to avoid potential sleep.

Self-verification:
root@localhost:/# perf record -e hisi_ptt0_2/filter=0x80001,type=1,dir
ection=1,format=1/ -- sleep 5
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.009 MB perf.data ]
root@localhost:/# 
root@localhost:/# ls
bin            home           perf.data      sbin           var
data           init           perf.data.old  sys            vendor
dev            io_test        proc           sysroot
etc            lib            root           tmp
hns3.cfg       lib64          run            usr
root@localhost:/# 
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