public-mirrors/linux
1
0
Fork 0
mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-18 22:14:16 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

virtio_rtc: Add Arm Generic Timer cross-timestamping

Browse source 
For platforms using the Arm Generic Timer, add precise cross-timestamping
support to virtio_rtc.

Always report the CP15 virtual counter as the HW counter in use by
arm_arch_timer, since the Linux kernel's usage of the Arm Generic Timer
should always be compatible with this.

Signed-off-by: Peter Hilber <quic_philber@quicinc.com>
Message-Id: <20250509160734.1772-4-quic_philber@quicinc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Peter Hilber 2025-05-09 18:07:24 +02:00 • committed by Michael S. Tsirkin
parent 9a17125a18
commit e2ef16757b
3 changed files with 37 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

13
drivers/virtio/Kconfig
View file

@ -221,6 +221,19 @@ config VIRTIO_RTC_PTP
If unsure, say Y.
config VIRTIO_RTC_ARM
bool "Virtio RTC cross-timestamping using Arm Generic Timer"
default y
depends on VIRTIO_RTC_PTP && ARM_ARCH_TIMER
help
This enables Virtio RTC cross-timestamping using the Arm Generic Timer.
It only has an effect if the Virtio RTC device also supports this. The
cross-timestamp is available through the PTP clock driver precise
cross-timestamp ioctl (PTP_SYS_OFFSET_PRECISE2 aka
PTP_SYS_OFFSET_PRECISE).
If unsure, say Y.
endif # VIRTIO_RTC
endif # VIRTIO_MENU

1
drivers/virtio/Makefile
View file

@ -17,3 +17,4 @@ obj-$(CONFIG_VIRTIO_DEBUG) += virtio_debug.o
obj-$(CONFIG_VIRTIO_RTC) += virtio_rtc.o
virtio_rtc-y := virtio_rtc_driver.o
virtio_rtc-$(CONFIG_VIRTIO_RTC_PTP) += virtio_rtc_ptp.o
virtio_rtc-$(CONFIG_VIRTIO_RTC_ARM) += virtio_rtc_arm.o

23
drivers/virtio/virtio_rtc_arm.c Normal file
View file

@ -0,0 +1,23 @@
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Provides cross-timestamp params for Arm.
*
* Copyright (C) 2022-2023 OpenSynergy GmbH
* Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
*/
#include <linux/clocksource_ids.h>
#include <uapi/linux/virtio_rtc.h>
#include "virtio_rtc_internal.h"
/* see header for doc */
int viortc_hw_xtstamp_params(u8 *hw_counter, enum clocksource_ids *cs_id)
{
*hw_counter = VIRTIO_RTC_COUNTER_ARM_VCT;
*cs_id = CSID_ARM_ARCH_COUNTER;
return 0;
}