[RFC PATCH 1/5] arm:omap1/2/3/4:Convert 32k-Sync clocksource driver to platform_driver

Vaibhav Hiremath hvaibhav at ti.com
Wed Jan 18 06:28:02 EST 2012


Convert counter_32k clocksource driver to standard platform_driver
and move it drivers/clocksource/ directory.

Also, rename it to more generic name "omap-32k.c".

Signed-off-by: Vaibhav Hiremath <hvaibhav at ti.com>
Signed-off-by: Felipe Balbi <balbi at ti.com>
Cc: Benoit Cousson <b-cousson at ti.com>
Cc: Tony Lindgren <tony at atomide.com>
Cc: Paul Walmsley <paul at pwsan.com>
Cc: Tarun Kanti DebBarma <tarun.kanti at ti.com>
Cc: Kevin Hilman <khilman at ti.com>
---
 arch/arm/mach-omap2/timer.c      |   17 ---
 arch/arm/plat-omap/Makefile      |    2 +-
 arch/arm/plat-omap/counter_32k.c |  154 ----------------------------
 drivers/clocksource/Makefile     |    1 +
 drivers/clocksource/omap-32k.c   |  210 ++++++++++++++++++++++++++++++++++++++
 include/linux/clocksource.h      |    1 +
 6 files changed, 213 insertions(+), 172 deletions(-)
 delete mode 100644 arch/arm/plat-omap/counter_32k.c
 create mode 100644 drivers/clocksource/omap-32k.c

diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index bfae81b..46b81df 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -233,22 +233,6 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
 		gptimer_id, clkev.rate);
 }

-/* Clocksource code */
-
-#ifdef CONFIG_OMAP_32K_TIMER
-/*
- * When 32k-timer is enabled, don't use GPTimer for clocksource
- * instead, just leave default clocksource which uses the 32k
- * sync counter.  See clocksource setup in plat-omap/counter_32k.c
- */
-
-static void __init omap2_gp_clocksource_init(int unused, const char *dummy)
-{
-	omap_init_clocksource_32k();
-}
-
-#else
-
 static struct omap_dm_timer clksrc;

 /*
@@ -307,7 +291,6 @@ static void __init omap2_gp_clocksource_init(int gptimer_id,
 		pr_err("Could not register clocksource %s\n",
 			clocksource_gpt.name);
 }
-#endif

 #define OMAP_SYS_TIMER_INIT(name, clkev_nr, clkev_src,			\
 				clksrc_nr, clksrc_src)			\
diff --git a/arch/arm/plat-omap/Makefile b/arch/arm/plat-omap/Makefile
index 9a58461..b35bb93 100644
--- a/arch/arm/plat-omap/Makefile
+++ b/arch/arm/plat-omap/Makefile
@@ -4,7 +4,7 @@

 # Common support
 obj-y := common.o sram.o clock.o devices.o dma.o mux.o \
-	 usb.o fb.o counter_32k.o
+	 usb.o fb.o
 obj-m :=
 obj-n :=
 obj-  :=
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c
deleted file mode 100644
index a6cbb71..0000000
--- a/arch/arm/plat-omap/counter_32k.c
+++ /dev/null
@@ -1,154 +0,0 @@
-/*
- * OMAP 32ksynctimer/counter_32k-related code
- *
- * Copyright (C) 2009 Texas Instruments
- * Copyright (C) 2010 Nokia Corporation
- * Tony Lindgren <tony at atomide.com>
- * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar at ti.com>
- *
- * 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.
- *
- * NOTE: This timer is not the same timer as the old OMAP1 MPU timer.
- */
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/clk.h>
-#include <linux/err.h>
-#include <linux/io.h>
-#include <linux/sched.h>
-#include <linux/clocksource.h>
-
-#include <asm/sched_clock.h>
-
-#include <plat/common.h>
-#include <plat/board.h>
-
-#include <plat/clock.h>
-
-/*
- * 32KHz clocksource ... always available, on pretty most chips except
- * OMAP 730 and 1510.  Other timers could be used as clocksources, with
- * higher resolution in free-running counter modes (e.g. 12 MHz xtal),
- * but systems won't necessarily want to spend resources that way.
- */
-static void __iomem *timer_32k_base;
-
-#define OMAP16XX_TIMER_32K_SYNCHRONIZED		0xfffbc410
-
-/*
- * Returns current time from boot in nsecs. It's OK for this to wrap
- * around for now, as it's just a relative time stamp.
- */
-static DEFINE_CLOCK_DATA(cd);
-
-/*
- * Constants generated by clocks_calc_mult_shift(m, s, 32768, NSEC_PER_SEC, 60).
- * This gives a resolution of about 30us and a wrap period of about 36hrs.
- */
-#define SC_MULT		4000000000u
-#define SC_SHIFT	17
-
-static inline unsigned long long notrace _omap_32k_sched_clock(void)
-{
-	u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
-	return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
-}
-
-#if defined(CONFIG_OMAP_32K_TIMER) && !defined(CONFIG_OMAP_MPU_TIMER)
-unsigned long long notrace sched_clock(void)
-{
-	return _omap_32k_sched_clock();
-}
-#else
-unsigned long long notrace omap_32k_sched_clock(void)
-{
-	return _omap_32k_sched_clock();
-}
-#endif
-
-static void notrace omap_update_sched_clock(void)
-{
-	u32 cyc = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
-	update_sched_clock(&cd, cyc, (u32)~0);
-}
-
-/**
- * read_persistent_clock -  Return time from a persistent clock.
- *
- * Reads the time from a source which isn't disabled during PM, the
- * 32k sync timer.  Convert the cycles elapsed since last read into
- * nsecs and adds to a monotonically increasing timespec.
- */
-static struct timespec persistent_ts;
-static cycles_t cycles, last_cycles;
-static unsigned int persistent_mult, persistent_shift;
-void read_persistent_clock(struct timespec *ts)
-{
-	unsigned long long nsecs;
-	cycles_t delta;
-	struct timespec *tsp = &persistent_ts;
-
-	last_cycles = cycles;
-	cycles = timer_32k_base ? __raw_readl(timer_32k_base) : 0;
-	delta = cycles - last_cycles;
-
-	nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift);
-
-	timespec_add_ns(tsp, nsecs);
-	*ts = *tsp;
-}
-
-int __init omap_init_clocksource_32k(void)
-{
-	static char err[] __initdata = KERN_ERR
-			"%s: can't register clocksource!\n";
-
-	if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
-		u32 pbase;
-		unsigned long size = SZ_4K;
-		void __iomem *base;
-		struct clk *sync_32k_ick;
-
-		if (cpu_is_omap16xx()) {
-			pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED;
-			size = SZ_1K;
-		} else if (cpu_is_omap2420())
-			pbase = OMAP2420_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap2430())
-			pbase = OMAP2430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap34xx())
-			pbase = OMAP3430_32KSYNCT_BASE + 0x10;
-		else if (cpu_is_omap44xx())
-			pbase = OMAP4430_32KSYNCT_BASE + 0x10;
-		else
-			return -ENODEV;
-
-		/* For this to work we must have a static mapping in io.c for this area */
-		base = ioremap(pbase, size);
-		if (!base)
-			return -ENODEV;
-
-		sync_32k_ick = clk_get(NULL, "omap_32ksync_ick");
-		if (!IS_ERR(sync_32k_ick))
-			clk_enable(sync_32k_ick);
-
-		timer_32k_base = base;
-
-		/*
-		 * 120000 rough estimate from the calculations in
-		 * __clocksource_updatefreq_scale.
-		 */
-		clocks_calc_mult_shift(&persistent_mult, &persistent_shift,
-				32768, NSEC_PER_SEC, 120000);
-
-		if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32,
-					  clocksource_mmio_readl_up))
-			printk(err, "32k_counter");
-
-		init_fixed_sched_clock(&cd, omap_update_sched_clock, 32,
-				       32768, SC_MULT, SC_SHIFT);
-	}
-	return 0;
-}
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 8d81a1d..0f5d5d2 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -9,4 +9,5 @@ obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
 obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
+obj-$(CONFIG_OMAP_32K_TIMER)	+= omap-32k.o
 obj-$(CONFIG_CLKSRC_DBX500_PRCMU)	+= clksrc-dbx500-prcmu.o
\ No newline at end of file
diff --git a/drivers/clocksource/omap-32k.c b/drivers/clocksource/omap-32k.c
new file mode 100644
index 0000000..f6d579e
--- /dev/null
+++ b/drivers/clocksource/omap-32k.c
@@ -0,0 +1,210 @@
+/*
+ * omap-32k.c -- OMAP 32k Sync Timer Clocksource Driver
+ *
+ * Copyright (C) 2005-2010 Tony Lindgren <t... at atomide.com>
+ * Copyright (C) 2010 Nokia Corporation
+ * Copyright (C) 2010 Felipe Balbi <m... at felipebalbi.com>
+ * Copyright (C) 2009-2010 Texas Instruments
+ * Added OMAP4 support - Santosh Shilimkar <santosh.shilim... at ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/clocksource.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/err.h>
+#include <linux/module.h>
+
+struct omap_counter_32k_device {
+	struct timespec		persistent_ts;
+	struct clocksource	cs;
+	cycles_t		cycles;
+	cycles_t		last_cycles;
+
+	struct device		*dev;
+	void __iomem		*base;
+};
+
+#define to_omap_32k(cs)	(container_of(cs, struct omap_counter_32k_device, cs))
+
+static struct omap_counter_32k_device	*cs;
+
+static inline u32 omap_counter_32k_readl(const void __iomem *base,
+		unsigned offset)
+{
+	return __raw_readl(base + offset);
+}
+
+static cycle_t omap_counter_32k_read(struct clocksource *cs)
+{
+	struct omap_counter_32k_device  *omap = to_omap_32k(cs);
+
+	return omap_counter_32k_readl(omap->base, 0x10);
+}
+
+/*
+ * Returns current time from boot in nsecs. It's OK for this to wrap
+ * around for now, as it's just a relative time stamp.
+ *
+ * NOTE: There is common sched_clock() function in mach-omap2/timer.c
+ *       file from where this function will be called.
+ *       Return 0, means the device doesn't have 32k-sync timer and
+ *       execution will fallback to gp-timer.
+ */
+unsigned long long sched_clock_32k(void)
+{
+	struct omap_counter_32k_device  *omap = cs;
+
+	if (!omap)
+		return 0;
+
+	return clocksource_cyc2ns(omap->cs.read(&omap->cs),
+			omap->cs.mult, omap->cs.shift);
+}
+
+/**
+ * read_persistent_clock -  Return time from a persistent clock.
+ *
+ * Reads the time from a source which isn't disabled during PM, the
+ * 32k sync timer.  Convert the cycles elapsed since last read into
+ * nsecs and adds to a monotonically increasing timespec.
+ */
+void read_persistent_clock(struct timespec *ts)
+{
+	cycles_t delta;
+	struct timespec *tsp;
+	unsigned long long nsecs;
+	struct omap_counter_32k_device  *omap = cs;
+
+	if (!omap) {
+		ts->tv_sec = 0;
+		ts->tv_nsec = 0;
+		return;
+	}
+	tsp = &omap->persistent_ts;
+
+	omap->last_cycles = omap->cycles;
+	omap->cycles = omap->cs.read(&omap->cs);
+	delta = omap->cycles - omap->last_cycles;
+
+	nsecs = clocksource_cyc2ns(delta,
+			omap->cs.mult, omap->cs.shift);
+
+	timespec_add_ns(tsp, nsecs);
+	*ts = *tsp;
+}
+
+static int __init omap_counter_32k_probe(struct platform_device *pdev)
+{
+	int ret;
+	void __iomem *base;
+	struct resource *res;
+	struct omap_counter_32k_device *omap;
+
+	omap = kzalloc(sizeof(*omap), GFP_KERNEL);
+	if (!omap) {
+		dev_dbg(&pdev->dev, "unable to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_dbg(&pdev->dev, "couldn't get resource\n");
+		ret = -ENODEV;
+		goto err0;
+	}
+
+	base = ioremap(res->start, resource_size(res));
+	if (!base) {
+		dev_dbg(&pdev->dev, "ioremap failed\n");
+		ret = -ENOMEM;
+		goto err0;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+	ret = pm_runtime_get(&pdev->dev);
+	if (ret) {
+		dev_dbg(&pdev->dev, "unable to enable runtime pm\n");
+		goto err1;
+	}
+
+	omap->base      = base;
+	omap->dev       = &pdev->dev;
+
+	omap->cs.name   = "counter-32k";
+	omap->cs.rating = 250;
+	omap->cs.read   = omap_counter_32k_read;
+	omap->cs.mask   = CLOCKSOURCE_MASK(32);
+	omap->cs.flags  = CLOCK_SOURCE_IS_CONTINUOUS;
+
+	platform_set_drvdata(pdev, omap);
+
+	ret = clocksource_register_hz(&omap->cs, 32768);
+	if (ret) {
+		dev_dbg(&pdev->dev, "failed to register clocksource\n");
+		goto err2;
+	}
+
+	cs = omap;
+	return 0;
+
+err2:
+	pm_runtime_put(&pdev->dev);
+err1:
+	iounmap(base);
+err0:
+	kfree(omap);
+	return ret;
+}
+
+static int __exit omap_counter_32k_remove(struct platform_device *pdev)
+{
+	struct omap_counter_32k_device  *omap = platform_get_drvdata(pdev);
+
+	clocksource_unregister(&omap->cs);
+	pm_runtime_put(&pdev->dev);
+	iounmap(omap->base);
+	kfree(omap);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver omap_counter_32k_driver = {
+	.remove		= __exit_p(omap_counter_32k_remove),
+	.driver		= {
+		.name	= "omap-counter-32k",
+	},
+};
+
+static int __init omap_counter_32k_init(void)
+{
+	return platform_driver_probe(&omap_counter_32k_driver,
+			omap_counter_32k_probe);
+}
+arch_initcall(omap_counter_32k_init);
+
+static void __exit omap_counter_32k_exit(void)
+{
+	platform_driver_unregister(&omap_counter_32k_driver);
+}
+module_exit(omap_counter_32k_exit);
+
+MODULE_AUTHOR("Felipe Balbi <balbi at ti.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index c86c940..67f6067 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -349,5 +349,6 @@ extern int clocksource_mmio_init(void __iomem *, const char *,
 	unsigned long, int, unsigned, cycle_t (*)(struct clocksource *));

 extern int clocksource_i8253_init(void);
+extern unsigned long long sched_clock_32k(void);

 #endif /* _LINUX_CLOCKSOURCE_H */
--
1.7.0.4




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