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authorSrinidhi Kasagar <srinidhi.kasagar@stericsson.com>2009-11-12 06:20:54 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2009-11-28 10:22:51 +0000
commit59b559d7a39b590aecef583af58d123ff5876570 (patch)
tree5e5f17bea4e3eb0295e6d85dc72334f23bbc9338 /arch/arm/plat-nomadik
parenta8a8a669ea13d792296737505adc43ccacf3a648 (diff)
ARM: 5786/1: Introduce plat-nomadik, MTU code re-organization
Introduce the plat-nomadik folder for ST-Ericsson machines including the existing nomadik 8815 architecture. This also moves the existing MTU (MultiTimerUnit) of nomadik 8815 to the proposed plat-nomadik and adds HAS_MTU. The patch has been re-based to 2.6.32-rc6 Signed-off-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com> Acked-by: Alessandro Rubini <rubini@unipv.it> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/plat-nomadik')
-rw-r--r--arch/arm/plat-nomadik/Kconfig22
-rw-r--r--arch/arm/plat-nomadik/Makefile5
-rw-r--r--arch/arm/plat-nomadik/include/plat/mtu.h48
-rw-r--r--arch/arm/plat-nomadik/timer.c147
4 files changed, 222 insertions, 0 deletions
diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
new file mode 100644
index 000000000000..e27ee3134056
--- /dev/null
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -0,0 +1,22 @@
+# We keep common IP's here for Nomadik and other similar
+# familiy of processors from ST-Ericsson. At the moment we have
+# just MTU, others to follow soon.
+
+config PLAT_NOMADIK
+ bool
+ depends on ARCH_NOMADIK
+ default y
+ help
+ Common platform code for Nomadik and other ST-Ericsson
+ platforms.
+
+if PLAT_NOMADIK
+
+config HAS_MTU
+ bool
+ help
+ Support for Multi Timer Unit. MTU provides access
+ to multiple interrupt generating programmable
+ 32-bit free running decrementing counters.
+
+endif
diff --git a/arch/arm/plat-nomadik/Makefile b/arch/arm/plat-nomadik/Makefile
new file mode 100644
index 000000000000..37c7cdd0f8f0
--- /dev/null
+++ b/arch/arm/plat-nomadik/Makefile
@@ -0,0 +1,5 @@
+# arch/arm/plat-nomadik/Makefile
+# Copyright 2009 ST-Ericsson
+# Licensed under GPLv2
+
+obj-$(CONFIG_HAS_MTU) += timer.o
diff --git a/arch/arm/plat-nomadik/include/plat/mtu.h b/arch/arm/plat-nomadik/include/plat/mtu.h
new file mode 100644
index 000000000000..42c907258b14
--- /dev/null
+++ b/arch/arm/plat-nomadik/include/plat/mtu.h
@@ -0,0 +1,48 @@
+#ifndef __PLAT_MTU_H
+#define __PLAT_MTU_H
+
+/* should be set by the platform code */
+extern void __iomem *mtu_base;
+
+/*
+ * The MTU device hosts four different counters, with 4 set of
+ * registers. These are register names.
+ */
+
+#define MTU_IMSC 0x00 /* Interrupt mask set/clear */
+#define MTU_RIS 0x04 /* Raw interrupt status */
+#define MTU_MIS 0x08 /* Masked interrupt status */
+#define MTU_ICR 0x0C /* Interrupt clear register */
+
+/* per-timer registers take 0..3 as argument */
+#define MTU_LR(x) (0x10 + 0x10 * (x) + 0x00) /* Load value */
+#define MTU_VAL(x) (0x10 + 0x10 * (x) + 0x04) /* Current value */
+#define MTU_CR(x) (0x10 + 0x10 * (x) + 0x08) /* Control reg */
+#define MTU_BGLR(x) (0x10 + 0x10 * (x) + 0x0c) /* At next overflow */
+
+/* bits for the control register */
+#define MTU_CRn_ENA 0x80
+#define MTU_CRn_PERIODIC 0x40 /* if 0 = free-running */
+#define MTU_CRn_PRESCALE_MASK 0x0c
+#define MTU_CRn_PRESCALE_1 0x00
+#define MTU_CRn_PRESCALE_16 0x04
+#define MTU_CRn_PRESCALE_256 0x08
+#define MTU_CRn_32BITS 0x02
+#define MTU_CRn_ONESHOT 0x01 /* if 0 = wraps reloading from BGLR*/
+
+/* Other registers are usual amba/primecell registers, currently not used */
+#define MTU_ITCR 0xff0
+#define MTU_ITOP 0xff4
+
+#define MTU_PERIPH_ID0 0xfe0
+#define MTU_PERIPH_ID1 0xfe4
+#define MTU_PERIPH_ID2 0xfe8
+#define MTU_PERIPH_ID3 0xfeC
+
+#define MTU_PCELL0 0xff0
+#define MTU_PCELL1 0xff4
+#define MTU_PCELL2 0xff8
+#define MTU_PCELL3 0xffC
+
+#endif /* __PLAT_MTU_H */
+
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c
new file mode 100644
index 000000000000..62f18ad43a28
--- /dev/null
+++ b/arch/arm/plat-nomadik/timer.c
@@ -0,0 +1,147 @@
+/*
+ * linux/arch/arm/mach-nomadik/timer.c
+ *
+ * Copyright (C) 2008 STMicroelectronics
+ * Copyright (C) 2009 Alessandro Rubini, somewhat based on at91sam926x
+ *
+ * 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.
+ */
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/clockchips.h>
+#include <linux/jiffies.h>
+#include <asm/mach/time.h>
+
+#include <plat/mtu.h>
+
+static u32 nmdk_count; /* accumulated count */
+static u32 nmdk_cycle; /* write-once */
+
+/* setup by the platform code */
+void __iomem *mtu_base;
+
+/*
+ * clocksource: the MTU device is a decrementing counters, so we negate
+ * the value being read.
+ */
+static cycle_t nmdk_read_timer(struct clocksource *cs)
+{
+ u32 count = readl(mtu_base + MTU_VAL(0));
+ return nmdk_count + nmdk_cycle - count;
+
+}
+
+static struct clocksource nmdk_clksrc = {
+ .name = "mtu_0",
+ .rating = 120,
+ .read = nmdk_read_timer,
+ .shift = 20,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+/*
+ * Clockevent device: currently only periodic mode is supported
+ */
+static void nmdk_clkevt_mode(enum clock_event_mode mode,
+ struct clock_event_device *dev)
+{
+ unsigned long flags;
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ /* enable interrupts -- and count current value? */
+ raw_local_irq_save(flags);
+ writel(readl(mtu_base + MTU_IMSC) | 1, mtu_base + MTU_IMSC);
+ raw_local_irq_restore(flags);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ BUG(); /* Not supported, yet */
+ /* FALLTHROUGH */
+ case CLOCK_EVT_MODE_SHUTDOWN:
+ case CLOCK_EVT_MODE_UNUSED:
+ /* disable irq */
+ raw_local_irq_save(flags);
+ writel(readl(mtu_base + MTU_IMSC) & ~1, mtu_base + MTU_IMSC);
+ raw_local_irq_restore(flags);
+ break;
+ case CLOCK_EVT_MODE_RESUME:
+ break;
+ }
+}
+
+static struct clock_event_device nmdk_clkevt = {
+ .name = "mtu_0",
+ .features = CLOCK_EVT_FEAT_PERIODIC,
+ .shift = 32,
+ .rating = 100,
+ .set_mode = nmdk_clkevt_mode,
+};
+
+/*
+ * IRQ Handler for the timer 0 of the MTU block. The irq is not shared
+ * as we are the only users of mtu0 by now.
+ */
+static irqreturn_t nmdk_timer_interrupt(int irq, void *dev_id)
+{
+ /* ack: "interrupt clear register" */
+ writel(1 << 0, mtu_base + MTU_ICR);
+
+ /* we can't count lost ticks, unfortunately */
+ nmdk_count += nmdk_cycle;
+ nmdk_clkevt.event_handler(&nmdk_clkevt);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * Set up timer interrupt, and return the current time in seconds.
+ */
+static struct irqaction nmdk_timer_irq = {
+ .name = "Nomadik Timer Tick",
+ .flags = IRQF_DISABLED | IRQF_TIMER,
+ .handler = nmdk_timer_interrupt,
+};
+
+static void nmdk_timer_reset(void)
+{
+ u32 cr;
+
+ writel(0, mtu_base + MTU_CR(0)); /* off */
+
+ /* configure load and background-load, and fire it up */
+ writel(nmdk_cycle, mtu_base + MTU_LR(0));
+ writel(nmdk_cycle, mtu_base + MTU_BGLR(0));
+ cr = MTU_CRn_PERIODIC | MTU_CRn_PRESCALE_1 | MTU_CRn_32BITS;
+ writel(cr, mtu_base + MTU_CR(0));
+ writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0));
+}
+
+void __init nmdk_timer_init(void)
+{
+ unsigned long rate;
+ int bits;
+
+ rate = CLOCK_TICK_RATE; /* 2.4MHz */
+ nmdk_cycle = (rate + HZ/2) / HZ;
+
+ /* Init the timer and register clocksource */
+ nmdk_timer_reset();
+
+ nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift);
+ bits = 8*sizeof(nmdk_count);
+ nmdk_clksrc.mask = CLOCKSOURCE_MASK(bits);
+
+ if (clocksource_register(&nmdk_clksrc))
+ printk(KERN_ERR "timer: failed to initialize clock "
+ "source %s\n", nmdk_clksrc.name);
+
+ /* Register irq and clockevents */
+ setup_irq(IRQ_MTU0, &nmdk_timer_irq);
+ nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift);
+ nmdk_clkevt.cpumask = cpumask_of(0);
+ clockevents_register_device(&nmdk_clkevt);
+}