[PATCH v2 4/5] tegra: add proper timer driver
Lucas Stach
dev at lynxeye.de
Thu Mar 7 05:33:21 EST 2013
Replace the ad-hoc clocksource implementation with a proper driver for
the Tegra 20 timer. This driver is able to do the required hardware
initialisation itself.
Signed-off-by: Lucas Stach <dev at lynxeye.de>
---
arch/arm/mach-tegra/Makefile | 2 +-
arch/arm/mach-tegra/clock.c | 56 -----------------
arch/arm/mach-tegra/tegra20-car.c | 5 ++
arch/arm/mach-tegra/tegra20-timer.c | 120 ++++++++++++++++++++++++++++++++++++
arch/arm/mach-tegra/tegra20.c | 4 ++
5 files changed, 130 insertions(+), 57 deletions(-)
delete mode 100644 arch/arm/mach-tegra/clock.c
create mode 100644 arch/arm/mach-tegra/tegra20-timer.c
diff --git a/arch/arm/mach-tegra/Makefile b/arch/arm/mach-tegra/Makefile
index 3391528..6aa219c 100644
--- a/arch/arm/mach-tegra/Makefile
+++ b/arch/arm/mach-tegra/Makefile
@@ -1,4 +1,4 @@
-obj-y += clock.o
obj-y += reset.o
obj-y += tegra20.o
obj-y += tegra20-car.o
+obj-y += tegra20-timer.o
diff --git a/arch/arm/mach-tegra/clock.c b/arch/arm/mach-tegra/clock.c
deleted file mode 100644
index 82065ee..0000000
--- a/arch/arm/mach-tegra/clock.c
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2011 Antony Pavlov <antonynpavlov at gmail.com>
- *
- * This file is part of barebox.
- * See file CREDITS for list of people who contributed to this project.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- */
-
-/**
- * @file
- * @brief Clocksource based on Tegra internal timer
- */
-
-#include <common.h>
-#include <clock.h>
-#include <linux/list.h>
-#include <linux/clk.h>
-#include <init.h>
-#include <asm/io.h>
-#include <mach/iomap.h>
-
-static void __iomem *timer_reg_base = (void __iomem *) (TEGRA_TMR1_BASE);
-
-#define timer_writel(value, reg) \
- __raw_writel(value, (u32)timer_reg_base + (reg))
-#define timer_readl(reg) \
- __raw_readl((u32)timer_reg_base + (reg))
-
-static uint64_t tegra_clocksource_read(void)
-{
- return timer_readl(0x10);
-}
-
-static struct clocksource cs = {
- .read = tegra_clocksource_read,
- .mask = 0xffffffff,
-};
-
-/* FIXME: here we have no initialization. All initialization made by U-Boot */
-static int clocksource_init(void)
-{
- cs.mult = clocksource_hz2mult(1000000, cs.shift);
- init_clock(&cs);
-
- return 0;
-}
-core_initcall(clocksource_init);
diff --git a/arch/arm/mach-tegra/tegra20-car.c b/arch/arm/mach-tegra/tegra20-car.c
index eec3cc3..3ac389f 100644
--- a/arch/arm/mach-tegra/tegra20-car.c
+++ b/arch/arm/mach-tegra/tegra20-car.c
@@ -23,6 +23,7 @@
#include <init.h>
#include <io.h>
#include <linux/clk.h>
+#include <linux/clkdev.h>
#include <linux/err.h>
#include <mach/iomap.h>
@@ -97,6 +98,10 @@ static int tegra20_car_probe(struct device_d *dev)
/* timer is a gate, but as it's enabled by BOOTROM we needn't worry */
clks[timer] = clk_fixed_factor("timer", "clk_m", 1, 1);
+
+ /* device to clock links */
+ clkdev_add_physbase(clks[timer], TEGRA_TMR1_BASE, NULL);
+
return 0;
}
diff --git a/arch/arm/mach-tegra/tegra20-timer.c b/arch/arm/mach-tegra/tegra20-timer.c
new file mode 100644
index 0000000..6c1d302
--- /dev/null
+++ b/arch/arm/mach-tegra/tegra20-timer.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2013 Lucas Stach <l.stach at pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * @file
+ * @brief Device driver for the Tegra 20 timer, which exposes a clocksource.
+ */
+
+#include <common.h>
+#include <clock.h>
+#include <init.h>
+#include <io.h>
+#include <linux/clk.h>
+
+/* register definitions */
+#define TIMERUS_CNTR_1US 0x10
+#define TIMERUS_USEC_CFG 0x14
+
+static void __iomem *timer_base;
+
+static uint64_t tegra20_timer_cs_read(void)
+{
+ return readl(timer_base + TIMERUS_CNTR_1US);
+}
+
+static struct clocksource cs = {
+ .read = tegra20_timer_cs_read,
+ .mask = CLOCKSOURCE_MASK(32),
+};
+
+static int tegra20_timer_probe(struct device_d *dev)
+{
+ struct clk *timer_clk;
+ unsigned long rate;
+ u32 reg;
+
+ /* use only one timer */
+ if (timer_base)
+ return -EBUSY;
+
+ timer_base = dev_request_mem_region(dev, 0);
+ if (!timer_base) {
+ dev_err(dev, "could not get memory region\n");
+ return -ENODEV;
+ }
+
+ timer_clk = clk_get(dev, NULL);
+ if (!timer_clk) {
+ dev_err(dev, "could not get clock\n");
+ return -ENODEV;
+ }
+
+ clk_enable(timer_clk);
+
+ /*
+ * calibrate timer to run at 1MHz
+ * TIMERUS_USEC_CFG selects the scale down factor with bits [0:7]
+ * representing the divisor and bits [8:15] representing the dividend
+ * each in n+1 form.
+ */
+ rate = clk_get_rate(timer_clk);
+ switch (rate) {
+ case 12000000:
+ reg = 0x000b;
+ break;
+ case 13000000:
+ reg = 0x000c;
+ break;
+ case 19200000:
+ reg = 0x045f;
+ break;
+ case 26000000:
+ reg = 0x0019;
+ break;
+ default:
+ reg = 0;
+ dev_warn(dev, "unknown timer clock rate\n");
+ break;
+ }
+ writel(reg, timer_base + TIMERUS_USEC_CFG);
+
+ cs.mult = clocksource_hz2mult(1000000, cs.shift);
+ init_clock(&cs);
+
+ return 0;
+}
+
+static __maybe_unused struct of_device_id tegra20_timer_dt_ids[] = {
+ {
+ .compatible = "nvidia,tegra20-timer",
+ }, {
+ /* sentinel */
+ }
+};
+
+static struct driver_d tegra20_timer_driver = {
+ .probe = tegra20_timer_probe,
+ .name = "tegra20-timer",
+ .of_compatible = DRV_OF_COMPAT(tegra20_timer_dt_ids),
+};
+
+static int tegra20_timer_init(void)
+{
+ return platform_driver_register(&tegra20_timer_driver);
+}
+
+coredevice_initcall(tegra20_timer_init);
diff --git a/arch/arm/mach-tegra/tegra20.c b/arch/arm/mach-tegra/tegra20.c
index 3831f1b..c1b3f78 100644
--- a/arch/arm/mach-tegra/tegra20.c
+++ b/arch/arm/mach-tegra/tegra20.c
@@ -24,6 +24,10 @@ static int tegra20_init(void)
TEGRA_CLK_RESET_BASE, TEGRA_CLK_RESET_SIZE,
IORESOURCE_MEM, NULL);
+ add_generic_device("tegra20-timer", DEVICE_ID_SINGLE, NULL,
+ TEGRA_TMR1_BASE, TEGRA_TMR1_SIZE,
+ IORESOURCE_MEM, NULL);
+
return 0;
}
--
1.8.1.2
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