From 40b0425f8ba17c32cf7182975032a3999c364dfc Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Mon, 7 Aug 2023 22:33:19 +0300 Subject: [PATCH] net: ptp: create a mock-up PTP Hardware Clock driver There are several cases where virtual net devices may benefit from having a PTP clock, and these have to do with testing. I can see at least netdevsim and veth as potential users of a common mock-up PTP hardware clock driver. The proposed idea is to create an object which emulates PTP clock operations on top of the unadjustable CLOCK_MONOTONIC_RAW plus a software-controlled time domain via a timecounter/cyclecounter and then link that PHC to the netdevsim device. The driver is fully functional for its intended purpose, and it successfully passes the PTP selftests. $ cd tools/testing/selftests/ptp/ $ ./phc.sh /dev/ptp2 TEST: settime [ OK ] TEST: adjtime [ OK ] TEST: adjfreq [ OK ] Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20230807193324.4128292-7-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski --- MAINTAINERS | 7 ++ drivers/ptp/Kconfig | 11 +++ drivers/ptp/Makefile | 1 + drivers/ptp/ptp_mock.c | 175 +++++++++++++++++++++++++++++++++++++++++++++++ include/linux/ptp_mock.h | 38 ++++++++++ 5 files changed, 232 insertions(+) create mode 100644 drivers/ptp/ptp_mock.c create mode 100644 include/linux/ptp_mock.h diff --git a/MAINTAINERS b/MAINTAINERS index 6efcd87..49f0325 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17170,6 +17170,13 @@ F: drivers/ptp/* F: include/linux/ptp_cl* K: (?:\b|_)ptp(?:\b|_) +PTP MOCKUP CLOCK SUPPORT +M: Vladimir Oltean +L: netdev@vger.kernel.org +S: Maintained +F: drivers/ptp/ptp_mock.c +F: include/linux/ptp_mock.h + PTP VIRTUAL CLOCK SUPPORT M: Yangbo Lu L: netdev@vger.kernel.org diff --git a/drivers/ptp/Kconfig b/drivers/ptp/Kconfig index 32dff1b4..ed9d97a 100644 --- a/drivers/ptp/Kconfig +++ b/drivers/ptp/Kconfig @@ -155,6 +155,17 @@ config PTP_1588_CLOCK_IDTCM To compile this driver as a module, choose M here: the module will be called ptp_clockmatrix. +config PTP_1588_CLOCK_MOCK + tristate "Mock-up PTP clock" + depends on PTP_1588_CLOCK + help + This driver offers a set of PTP clock manipulation operations over + the system monotonic time. It can be used by virtual network device + drivers to emulate PTP capabilities. + + To compile this driver as a module, choose M here: the module + will be called ptp_mock. + config PTP_1588_CLOCK_VMW tristate "VMware virtual PTP clock" depends on ACPI && HYPERVISOR_GUEST && X86 diff --git a/drivers/ptp/Makefile b/drivers/ptp/Makefile index 553f18b..dea0ceb 100644 --- a/drivers/ptp/Makefile +++ b/drivers/ptp/Makefile @@ -16,6 +16,7 @@ ptp-qoriq-y += ptp_qoriq.o ptp-qoriq-$(CONFIG_DEBUG_FS) += ptp_qoriq_debugfs.o obj-$(CONFIG_PTP_1588_CLOCK_IDTCM) += ptp_clockmatrix.o obj-$(CONFIG_PTP_1588_CLOCK_IDT82P33) += ptp_idt82p33.o +obj-$(CONFIG_PTP_1588_CLOCK_MOCK) += ptp_mock.o obj-$(CONFIG_PTP_1588_CLOCK_VMW) += ptp_vmw.o obj-$(CONFIG_PTP_1588_CLOCK_OCP) += ptp_ocp.o obj-$(CONFIG_PTP_DFL_TOD) += ptp_dfl_tod.o diff --git a/drivers/ptp/ptp_mock.c b/drivers/ptp/ptp_mock.c new file mode 100644 index 0000000..e7b459c --- /dev/null +++ b/drivers/ptp/ptp_mock.c @@ -0,0 +1,175 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2023 NXP + * + * Mock-up PTP Hardware Clock driver for virtual network devices + * + * Create a PTP clock which offers PTP time manipulation operations + * using a timecounter/cyclecounter on top of CLOCK_MONOTONIC_RAW. + */ + +#include +#include +#include + +/* Clamp scaled_ppm between -2,097,152,000 and 2,097,152,000, + * and thus "adj" between -68,719,476 and 68,719,476 + */ +#define MOCK_PHC_MAX_ADJ_PPB 32000000 +/* Timestamps from ktime_get_raw() have 1 ns resolution, so the scale factor + * (MULT >> SHIFT) needs to be 1. Pick SHIFT as 31 bits, which translates + * MULT(freq 0) into 0x80000000. + */ +#define MOCK_PHC_CC_SHIFT 31 +#define MOCK_PHC_CC_MULT (1 << MOCK_PHC_CC_SHIFT) +#define MOCK_PHC_FADJ_SHIFT 9 +#define MOCK_PHC_FADJ_DENOMINATOR 15625ULL + +/* The largest cycle_delta that timecounter_read_delta() can handle without a + * 64-bit overflow during the multiplication with cc->mult, given the max "adj" + * we permit, is ~8.3 seconds. Make sure readouts are more frequent than that. + */ +#define MOCK_PHC_REFRESH_INTERVAL (HZ * 5) + +#define info_to_phc(d) container_of((d), struct mock_phc, info) + +struct mock_phc { + struct ptp_clock_info info; + struct ptp_clock *clock; + struct timecounter tc; + struct cyclecounter cc; + spinlock_t lock; +}; + +static u64 mock_phc_cc_read(const struct cyclecounter *cc) +{ + return ktime_get_raw_ns(); +} + +static int mock_phc_adjfine(struct ptp_clock_info *info, long scaled_ppm) +{ + struct mock_phc *phc = info_to_phc(info); + s64 adj; + + adj = (s64)scaled_ppm << MOCK_PHC_FADJ_SHIFT; + adj = div_s64(adj, MOCK_PHC_FADJ_DENOMINATOR); + + spin_lock(&phc->lock); + timecounter_read(&phc->tc); + phc->cc.mult = MOCK_PHC_CC_MULT + adj; + spin_unlock(&phc->lock); + + return 0; +} + +static int mock_phc_adjtime(struct ptp_clock_info *info, s64 delta) +{ + struct mock_phc *phc = info_to_phc(info); + + spin_lock(&phc->lock); + timecounter_adjtime(&phc->tc, delta); + spin_unlock(&phc->lock); + + return 0; +} + +static int mock_phc_settime64(struct ptp_clock_info *info, + const struct timespec64 *ts) +{ + struct mock_phc *phc = info_to_phc(info); + u64 ns = timespec64_to_ns(ts); + + spin_lock(&phc->lock); + timecounter_init(&phc->tc, &phc->cc, ns); + spin_unlock(&phc->lock); + + return 0; +} + +static int mock_phc_gettime64(struct ptp_clock_info *info, struct timespec64 *ts) +{ + struct mock_phc *phc = info_to_phc(info); + u64 ns; + + spin_lock(&phc->lock); + ns = timecounter_read(&phc->tc); + spin_unlock(&phc->lock); + + *ts = ns_to_timespec64(ns); + + return 0; +} + +static long mock_phc_refresh(struct ptp_clock_info *info) +{ + struct timespec64 ts; + + mock_phc_gettime64(info, &ts); + + return MOCK_PHC_REFRESH_INTERVAL; +} + +int mock_phc_index(struct mock_phc *phc) +{ + return ptp_clock_index(phc->clock); +} +EXPORT_SYMBOL_GPL(mock_phc_index); + +struct mock_phc *mock_phc_create(struct device *dev) +{ + struct mock_phc *phc; + int err; + + phc = kzalloc(sizeof(*phc), GFP_KERNEL); + if (!phc) { + err = -ENOMEM; + goto out; + } + + phc->info = (struct ptp_clock_info) { + .owner = THIS_MODULE, + .name = "Mock-up PTP clock", + .max_adj = MOCK_PHC_MAX_ADJ_PPB, + .adjfine = mock_phc_adjfine, + .adjtime = mock_phc_adjtime, + .gettime64 = mock_phc_gettime64, + .settime64 = mock_phc_settime64, + .do_aux_work = mock_phc_refresh, + }; + + phc->cc = (struct cyclecounter) { + .read = mock_phc_cc_read, + .mask = CYCLECOUNTER_MASK(64), + .mult = MOCK_PHC_CC_MULT, + .shift = MOCK_PHC_CC_SHIFT, + }; + + spin_lock_init(&phc->lock); + timecounter_init(&phc->tc, &phc->cc, 0); + + phc->clock = ptp_clock_register(&phc->info, dev); + if (IS_ERR(phc->clock)) { + err = PTR_ERR(phc->clock); + goto out_free_phc; + } + + ptp_schedule_worker(phc->clock, MOCK_PHC_REFRESH_INTERVAL); + + return phc; + +out_free_phc: + kfree(phc); +out: + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(mock_phc_create); + +void mock_phc_destroy(struct mock_phc *phc) +{ + ptp_clock_unregister(phc->clock); + kfree(phc); +} +EXPORT_SYMBOL_GPL(mock_phc_destroy); + +MODULE_DESCRIPTION("Mock-up PTP Hardware Clock driver"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/ptp_mock.h b/include/linux/ptp_mock.h new file mode 100644 index 0000000..72eb401 --- /dev/null +++ b/include/linux/ptp_mock.h @@ -0,0 +1,38 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Mock-up PTP Hardware Clock driver for virtual network devices + * + * Copyright 2023 NXP + */ + +#ifndef _PTP_MOCK_H_ +#define _PTP_MOCK_H_ + +struct device; +struct mock_phc; + +#if IS_ENABLED(CONFIG_PTP_1588_CLOCK_MOCK) + +struct mock_phc *mock_phc_create(struct device *dev); +void mock_phc_destroy(struct mock_phc *phc); +int mock_phc_index(struct mock_phc *phc); + +#else + +static inline struct mock_phc *mock_phc_create(struct device *dev) +{ + return NULL; +} + +static inline void mock_phc_destroy(struct mock_phc *phc) +{ +} + +static inline int mock_phc_index(struct mock_phc *phc) +{ + return -1; +} + +#endif + +#endif /* _PTP_MOCK_H_ */ -- 2.7.4