1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/clocksource/efi.c b/drivers/clocksource/efi.c
new file mode 100644
index 0000000000..89906c452e
--- /dev/null
+++ b/drivers/clocksource/efi.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2017 Jean-Christophe PLAGNIOL-VILLARD <plagnio@jcrosoft.com>
+ *
+ * Under GPL v2
+ */
+#include <common.h>
+#include <init.h>
+#include <driver.h>
+#include <clock.h>
+#include <efi.h>
+#include <efi/efi.h>
+#include <efi/efi-device.h>
+#include <linux/err.h>
+
+static uint64_t ticks = 1;
+static void *efi_cs_evt;
+
+static uint64_t efi_cs_read(void)
+{
+	return ticks;
+}
+
+static void efi_cs_inc(void *event, void *ctx)
+{
+	ticks++;
+}
+
+/* count ticks during a 1dms */
+static uint64_t ticks_freq(void)
+{
+	uint64_t ticks_start, ticks_end;
+
+	ticks_start = ticks;
+	BS->stall(1000);
+	ticks_end = ticks;
+
+	return (ticks_end - ticks_start) * 1000;
+}
+
+/* count ticks during a 20ms delay as on qemu x86_64 the max is 100Hz */
+static uint64_t ticks_freq_x86(void)
+{
+	uint64_t ticks_start, ticks_end;
+
+	ticks_start = ticks;
+	BS->stall(20 * 1000);
+	ticks_end = ticks;
+
+	return (ticks_end - ticks_start) * 50;
+}
+
+static int efi_cs_init(struct clocksource *cs)
+{
+	efi_status_t efiret;
+	uint64_t freq;
+
+	efiret = BS->create_event(EFI_EVT_TIMER | EFI_EVT_NOTIFY_SIGNAL,
+			EFI_TPL_CALLBACK, efi_cs_inc, NULL, &efi_cs_evt);
+
+	if (EFI_ERROR(efiret))
+		return -efi_errno(efiret);
+
+	efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, 10);
+	if (EFI_ERROR(efiret)) {
+		BS->close_event(efi_cs_evt);
+		return -efi_errno(efiret);
+	}
+
+	freq = 1000 * 1000;
+	if (ticks_freq() < 800 * 1000) {
+		uint64_t nb_100ns;
+
+		freq = ticks_freq_x86();
+		nb_100ns = 10 * 1000 * 1000 / freq;
+		pr_warn("EFI Event timer too slow freq = %llu Hz\n", freq);
+		efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, nb_100ns);
+		if (EFI_ERROR(efiret)) {
+			BS->close_event(efi_cs_evt);
+			return -efi_errno(efiret);
+		}
+	}
+
+	cs->mult = clocksource_hz2mult(freq, cs->shift);
+
+	return 0;
+}
+
+static struct clocksource efi_cs = {
+	.read   = efi_cs_read,
+	.mask   = CLOCKSOURCE_MASK(64),
+	.shift  = 0,
+	.init   = efi_cs_init,
+};
+
+static int efi_cs_probe(struct device_d *dev)
+{
+	return init_clock(&efi_cs);
+}
+
+static struct driver_d efi_cs_driver = {
+	.name = "efi-cs",
+	.probe = efi_cs_probe,
+};
+
+static int efi_cs_initcall(void)
+{
+	return platform_driver_register(&efi_cs_driver);
+}
+/* for efi the time must be init at core initcall level */
+core_initcall(efi_cs_initcall);