[U-Boot] [PATCH 04/20] tegra: Provide more accurate microsecond time

Simon Glass
2015-02-17T22:29:38Z

Add an implementation of the timer functions for tegra, so that timing
is more accurate. Tegra has a 1 microsecond timer for this purpose.

Signed-off-by: Simon Glass <sjg@chromium.org>
---

arch/arm/cpu/tegra-common/Makefile | 1 +
arch/arm/cpu/tegra-common/timer.c | 87 ++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
create mode 100644 arch/arm/cpu/tegra-common/timer.c

diff --git a/arch/arm/cpu/tegra-common/Makefile b/arch/arm/cpu/tegra-common/Makefile
index a78869e..3dbe97f 100644
--- a/arch/arm/cpu/tegra-common/Makefile
+++ b/arch/arm/cpu/tegra-common/Makefile
@@ -14,6 +14,7 @@ obj-y += clock.o
obj-y += lowlevel_init.o
obj-y += pinmux-common.o
obj-y += powergate.o
+obj-y += timer.o
obj-y += xusb-padctl.o
obj-$(CONFIG_DISPLAY_CPUINFO) += sys_info.o
obj-$(CONFIG_TEGRA124) += vpr.o
diff --git a/arch/arm/cpu/tegra-common/timer.c b/arch/arm/cpu/tegra-common/timer.c
new file mode 100644
index 0000000..c7f80a5
--- /dev/null
+++ b/arch/arm/cpu/tegra-common/timer.c
@@ -0,0 +1,87 @@
+/*
+ * (C) Copyright 2015 Googoe, Inc
+ * (C) Copyright 2010,2011
+ * NVIDIA Corporation <www.nvidia.com>
+ *
+ * (C) Copyright 2008
+ * Texas Instruments
+ *
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Syed Moahmmed Khasim <khasim@ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ * Alex Zuepke <azu@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/tegra.h>
+#include <asm/arch-tegra/timer.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* counter runs at 1MHz */
+#define TIMER_CLK 1000000
+#define TIMER_LOAD_VAL 0xffffffff
+
+/* timer without interrupts */
+ulong get_timer(ulong base)
+{
+ return get_timer_masked() - base;
+}
+
+/* delay x useconds */
+void __udelay(unsigned long usec)
+{
+ long tmo = usec * (TIMER_CLK / 1000) / 1000;
+ unsigned long now, last = timer_get_us();
+
+ while (tmo > 0) {
+ now = timer_get_us();
+ if (last > now) /* count up timer overflow */
+ tmo -= TIMER_LOAD_VAL - last + now;
+ else
+ tmo -= now - last;
+ last = now;
+ }
+}
+
+ulong get_timer_masked(void)
+{
+ ulong now;
+
+ /* current tick value */
+ now = timer_get_us() / (TIMER_CLK / CONFIG_SYS_HZ);
+
+ if (now >= gd->arch.lastinc) /* normal mode (non roll) */
+ /* move stamp forward with absolute diff ticks */
+ gd->arch.tbl += (now - gd->arch.lastinc);
+ else /* we have rollover of incrementer */
+ gd->arch.tbl += ((TIMER_LOAD_VAL / (TIMER_CLK / CONFIG_SYS_HZ))
+ - gd->arch.lastinc) + now;
+ gd->arch.lastinc = now;
+ return gd->arch.tbl;
+}
+
+/*
+ * This function is derived from PowerPC code (read timebase as long long).
+ * On ARM it just returns the timer value.
+ */
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+unsigned long timer_get_us(void)
+{
+ struct timerus *timer_base = (struct timerus *)NV_PA_TMRUS_BASE;
+
+ return readl(&timer_base->cntr_1us);
+}
--
2.2.0.rc0.207.ga3a616c