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path: root/drivers/ptp/ptp_kvm_common.c
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Diffstat (limited to 'drivers/ptp/ptp_kvm_common.c')
-rw-r--r--drivers/ptp/ptp_kvm_common.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/drivers/ptp/ptp_kvm_common.c b/drivers/ptp/ptp_kvm_common.c
new file mode 100644
index 000000000000..721ddcede5e1
--- /dev/null
+++ b/drivers/ptp/ptp_kvm_common.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Virtual PTP 1588 clock for use with KVM guests
+ *
+ * Copyright (C) 2017 Red Hat Inc.
+ */
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/ptp_kvm.h>
+#include <uapi/linux/kvm_para.h>
+#include <asm/kvm_para.h>
+#include <uapi/asm/kvm_para.h>
+
+#include <linux/ptp_clock_kernel.h>
+
+struct kvm_ptp_clock {
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info caps;
+};
+
+static DEFINE_SPINLOCK(kvm_ptp_lock);
+
+static int ptp_kvm_get_time_fn(ktime_t *device_time,
+ struct system_counterval_t *system_counter,
+ void *ctx)
+{
+ long ret;
+ u64 cycle;
+ struct timespec64 tspec;
+ struct clocksource *cs;
+
+ spin_lock(&kvm_ptp_lock);
+
+ preempt_disable_notrace();
+ ret = kvm_arch_ptp_get_crosststamp(&cycle, &tspec, &cs);
+ if (ret) {
+ spin_unlock(&kvm_ptp_lock);
+ preempt_enable_notrace();
+ return ret;
+ }
+
+ preempt_enable_notrace();
+
+ system_counter->cycles = cycle;
+ system_counter->cs = cs;
+
+ *device_time = timespec64_to_ktime(tspec);
+
+ spin_unlock(&kvm_ptp_lock);
+
+ return 0;
+}
+
+static int ptp_kvm_getcrosststamp(struct ptp_clock_info *ptp,
+ struct system_device_crosststamp *xtstamp)
+{
+ return get_device_system_crosststamp(ptp_kvm_get_time_fn, NULL,
+ NULL, xtstamp);
+}
+
+/*
+ * PTP clock operations
+ */
+
+static int ptp_kvm_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_settime(struct ptp_clock_info *ptp,
+ const struct timespec64 *ts)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ptp_kvm_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
+{
+ long ret;
+ struct timespec64 tspec;
+
+ spin_lock(&kvm_ptp_lock);
+
+ ret = kvm_arch_ptp_get_clock(&tspec);
+ if (ret) {
+ spin_unlock(&kvm_ptp_lock);
+ return ret;
+ }
+
+ spin_unlock(&kvm_ptp_lock);
+
+ memcpy(ts, &tspec, sizeof(struct timespec64));
+
+ return 0;
+}
+
+static int ptp_kvm_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static const struct ptp_clock_info ptp_kvm_caps = {
+ .owner = THIS_MODULE,
+ .name = "KVM virtual PTP",
+ .max_adj = 0,
+ .n_ext_ts = 0,
+ .n_pins = 0,
+ .pps = 0,
+ .adjfreq = ptp_kvm_adjfreq,
+ .adjtime = ptp_kvm_adjtime,
+ .gettime64 = ptp_kvm_gettime,
+ .settime64 = ptp_kvm_settime,
+ .enable = ptp_kvm_enable,
+ .getcrosststamp = ptp_kvm_getcrosststamp,
+};
+
+/* module operations */
+
+static struct kvm_ptp_clock kvm_ptp_clock;
+
+static void __exit ptp_kvm_exit(void)
+{
+ ptp_clock_unregister(kvm_ptp_clock.ptp_clock);
+}
+
+static int __init ptp_kvm_init(void)
+{
+ long ret;
+
+ ret = kvm_arch_ptp_init();
+ if (ret) {
+ pr_err("fail to initialize ptp_kvm");
+ return ret;
+ }
+
+ kvm_ptp_clock.caps = ptp_kvm_caps;
+
+ kvm_ptp_clock.ptp_clock = ptp_clock_register(&kvm_ptp_clock.caps, NULL);
+
+ return PTR_ERR_OR_ZERO(kvm_ptp_clock.ptp_clock);
+}
+
+module_init(ptp_kvm_init);
+module_exit(ptp_kvm_exit);
+
+MODULE_AUTHOR("Marcelo Tosatti <mtosatti@redhat.com>");
+MODULE_DESCRIPTION("PTP clock using KVMCLOCK");
+MODULE_LICENSE("GPL");