From bce9e7942ad39b8ecbbe592e6cae351c34b6991f Mon Sep 17 00:00:00 2001
From: Sajid Dalvi <sdalvi@google.com>
Date: Tue, 27 Jul 2021 17:31:07 -0500
Subject: [PATCH] ANDROID: PCI/PM: Use usleep_range for d3hot_delay

This patch implements a vendor hook that changes d3hot_delay to use
usleep_range() instead of msleep() to reduce the resume time from 20ms to 10ms.

The call sequence is as follows:
pci_pm_resume_noirq()
pci_pm_default_resume_early()
pci_power_up()
pci_raw_set_power_state() --> msleep(10)

The default d3hot_delay is 10ms. Using msleep for delays less than 20ms could
result in delays up to 20ms.
Reference: Documentation/timers/timers-howto.rst

Using usleep_range() results in the delay being closer to 10ms and this reduces
the resume time.

Bug: 194231641
Change-Id: If3e4dcfb99edad302371273933fa6784854cf892
Signed-off-by: Sajid Dalvi <sdalvi@google.com>
---
 drivers/android/vendor_hooks.c |  2 ++
 drivers/pci/pci.c              | 11 +++++++++--
 include/trace/hooks/pci.h      | 22 ++++++++++++++++++++++
 3 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 include/trace/hooks/pci.h

diff --git a/drivers/android/vendor_hooks.c b/drivers/android/vendor_hooks.c
index 0ae5d2f5e055..1302b9b0f5f2 100644
--- a/drivers/android/vendor_hooks.c
+++ b/drivers/android/vendor_hooks.c
@@ -73,6 +73,7 @@
 #include <trace/hooks/sound.h>
 #include <trace/hooks/snd_compr.h>
 #include <trace/hooks/ipv4.h>
+#include <trace/hooks/pci.h>
 
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
@@ -378,3 +379,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_tcp_recvmsg);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_udp_sendmsg);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_udp_recvmsg);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_tcp_recvmsg_stat);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_pci_d3_sleep);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index d5d9ea864fe6..e5c3fb43a791 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -31,6 +31,9 @@
 #include <linux/vmalloc.h>
 #include <asm/dma.h>
 #include <linux/aer.h>
+#ifndef  __GENKSYMS__
+#include <trace/hooks/pci.h>
+#endif
 #include "pci.h"
 
 DEFINE_MUTEX(pci_slot_mutex);
@@ -64,12 +67,16 @@ struct pci_pme_device {
 static void pci_dev_d3_sleep(struct pci_dev *dev)
 {
 	unsigned int delay = dev->d3hot_delay;
+	int err = -EOPNOTSUPP;
 
 	if (delay < pci_pm_d3hot_delay)
 		delay = pci_pm_d3hot_delay;
 
-	if (delay)
-		msleep(delay);
+	if (delay) {
+		trace_android_rvh_pci_d3_sleep(dev, delay, &err);
+		if (err == -EOPNOTSUPP)
+			msleep(delay);
+	}
 }
 
 #ifdef CONFIG_PCI_DOMAINS
diff --git a/include/trace/hooks/pci.h b/include/trace/hooks/pci.h
new file mode 100644
index 000000000000..d9c5e4aec7d1
--- /dev/null
+++ b/include/trace/hooks/pci.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM pci
+#define TRACE_INCLUDE_PATH trace/hooks
+
+#if !defined(_TRACE_HOOK_PCI_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_PCI_H
+#include <linux/tracepoint.h>
+#include <trace/hooks/vendor_hooks.h>
+/*
+ * Following tracepoints are not exported in tracefs and provide a
+ * mechanism for vendor modules to hook and extend functionality
+ */
+
+DECLARE_RESTRICTED_HOOK(android_rvh_pci_d3_sleep,
+             TP_PROTO(struct pci_dev *dev, unsigned int delay, int *err),
+             TP_ARGS(dev, delay, err), 1);
+
+#endif /* _TRACE_HOOK_PCI_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>