blackfin architecture

This adds support for the Analog Devices Blackfin processor architecture, and
currently supports the BF533, BF532, BF531, BF537, BF536, BF534, and BF561
(Dual Core) devices, with a variety of development platforms including those
avaliable from Analog Devices (BF533-EZKit, BF533-STAMP, BF537-STAMP,
BF561-EZKIT), and Bluetechnix!  Tinyboards.

The Blackfin architecture was jointly developed by Intel and Analog Devices
Inc.  (ADI) as the Micro Signal Architecture (MSA) core and introduced it in
December of 2000.  Since then ADI has put this core into its Blackfin
processor family of devices.  The Blackfin core has the advantages of a clean,
orthogonal,RISC-like microprocessor instruction set.  It combines a dual-MAC
(Multiply/Accumulate), state-of-the-art signal processing engine and
single-instruction, multiple-data (SIMD) multimedia capabilities into a single
instruction-set architecture.

The Blackfin architecture, including the instruction set, is described by the
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
http://blackfin.uclinux.org/gf/download/frsrelease/29/2549/Blackfin_PRM.pdf

The Blackfin processor is already supported by major releases of gcc, and
there are binary and source rpms/tarballs for many architectures at:
http://blackfin.uclinux.org/gf/project/toolchain/frs There is complete
documentation, including "getting started" guides available at:
http://docs.blackfin.uclinux.org/ which provides links to the sources and
patches you will need in order to set up a cross-compiling environment for
bfin-linux-uclibc

This patch, as well as the other patches (toolchain, distribution,
uClibc) are actively supported by Analog Devices Inc, at:
http://blackfin.uclinux.org/

We have tested this on LTP, and our test plan (including pass/fails) can
be found at:
http://docs.blackfin.uclinux.org/doku.php?id=testing_the_linux_kernel

[m.kozlowski@tuxland.pl: balance parenthesis in blackfin header files]
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Aubrey Li <aubrey.li@analog.com>
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 326 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/time.c b/arch/blackfin/kernel/time.c
new file mode 100644
index 000000000000..f578176b6d92
--- /dev/null
+++ b/arch/blackfin/kernel/time.c
@@ -0,0 +1,326 @@
+/*
+ * File:         arch/blackfin/kernel/time.c
+ * Based on:     none - original work
+ * Author:
+ *
+ * Created:
+ * Description:  This file contains the bfin-specific time handling details.
+ *               Most of the stuff is located in the machine specific files.
+ *
+ * Modified:
+ *               Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * 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, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/module.h>
+#include <linux/profile.h>
+#include <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/irq.h>
+
+#include <asm/blackfin.h>
+
+/* This is an NTP setting */
+#define	TICK_SIZE (tick_nsec / 1000)
+
+static void time_sched_init(irqreturn_t(*timer_routine)
+			(int, void *));
+static unsigned long gettimeoffset(void);
+static inline void do_leds(void);
+
+#if (defined(CONFIG_BFIN_ALIVE_LED) || defined(CONFIG_BFIN_IDLE_LED))
+void __init init_leds(void)
+{
+	unsigned int tmp = 0;
+
+#if defined(CONFIG_BFIN_ALIVE_LED)
+	/* config pins as output. */
+	tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_DPORT();
+	SSYNC();
+	bfin_write_CONFIG_BFIN_ALIVE_LED_DPORT(tmp | CONFIG_BFIN_ALIVE_LED_PIN);
+	SSYNC();
+
+	/*      First set led be off */
+	tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_PORT();
+	SSYNC();
+	bfin_write_CONFIG_BFIN_ALIVE_LED_PORT(tmp | CONFIG_BFIN_ALIVE_LED_PIN);	/* light off */
+	SSYNC();
+#endif
+
+#if defined(CONFIG_BFIN_IDLE_LED)
+	/* config pins as output. */
+	tmp = bfin_read_CONFIG_BFIN_IDLE_LED_DPORT();
+	SSYNC();
+	bfin_write_CONFIG_BFIN_IDLE_LED_DPORT(tmp | CONFIG_BFIN_IDLE_LED_PIN);
+	SSYNC();
+
+	/*      First set led be off */
+	tmp = bfin_read_CONFIG_BFIN_IDLE_LED_PORT();
+	SSYNC();
+	bfin_write_CONFIG_BFIN_IDLE_LED_PORT(tmp | CONFIG_BFIN_IDLE_LED_PIN);	/* light off */
+	SSYNC();
+#endif
+}
+#else
+void __init init_leds(void)
+{
+}
+#endif
+
+#if defined(CONFIG_BFIN_ALIVE_LED)
+static inline void do_leds(void)
+{
+	static unsigned int count = 50;
+	static int flag = 0;
+	unsigned short tmp = 0;
+
+	if (--count == 0) {
+		count = 50;
+		flag = ~flag;
+	}
+	tmp = bfin_read_CONFIG_BFIN_ALIVE_LED_PORT();
+	SSYNC();
+
+	if (flag)
+		tmp &= ~CONFIG_BFIN_ALIVE_LED_PIN;	/* light on */
+	else
+		tmp |= CONFIG_BFIN_ALIVE_LED_PIN;	/* light off */
+
+	bfin_write_CONFIG_BFIN_ALIVE_LED_PORT(tmp);
+	SSYNC();
+
+}
+#else
+static inline void do_leds(void)
+{
+}
+#endif
+
+static struct irqaction bfin_timer_irq = {
+	.name = "BFIN Timer Tick",
+	.flags = IRQF_DISABLED
+};
+
+/*
+ * The way that the Blackfin core timer works is:
+ *  - CCLK is divided by a programmable 8-bit pre-scaler (TSCALE)
+ *  - Every time TSCALE ticks, a 32bit is counted down (TCOUNT)
+ *
+ * If you take the fastest clock (1ns, or 1GHz to make the math work easier)
+ *    10ms is 10,000,000 clock ticks, which fits easy into a 32-bit counter
+ *    (32 bit counter is 4,294,967,296ns or 4.2 seconds) so, we don't need
+ *    to use TSCALE, and program it to zero (which is pass CCLK through).
+ *    If you feel like using it, try to keep HZ * TIMESCALE to some
+ *    value that divides easy (like power of 2).
+ */
+
+#define TIME_SCALE 1
+
+static void
+time_sched_init(irqreturn_t(*timer_routine) (int, void *))
+{
+	u32 tcount;
+
+	/* power up the timer, but don't enable it just yet */
+	bfin_write_TCNTL(1);
+	CSYNC();
+
+	/*
+	 * the TSCALE prescaler counter.
+	 */
+	bfin_write_TSCALE((TIME_SCALE - 1));
+
+	tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
+	bfin_write_TPERIOD(tcount);
+	bfin_write_TCOUNT(tcount);
+
+	/* now enable the timer */
+	CSYNC();
+
+	bfin_write_TCNTL(7);
+
+	bfin_timer_irq.handler = (irq_handler_t)timer_routine;
+	/* call setup_irq instead of request_irq because request_irq calls
+	 * kmalloc which has not been initialized yet
+	 */
+	setup_irq(IRQ_CORETMR, &bfin_timer_irq);
+}
+
+/*
+ * Should return useconds since last timer tick
+ */
+static unsigned long gettimeoffset(void)
+{
+	unsigned long offset;
+	unsigned long clocks_per_jiffy;
+
+	clocks_per_jiffy = bfin_read_TPERIOD();
+	offset =
+	    (clocks_per_jiffy -
+	     bfin_read_TCOUNT()) / (((clocks_per_jiffy + 1) * HZ) /
+				    USEC_PER_SEC);
+
+	/* Check if we just wrapped the counters and maybe missed a tick */
+	if ((bfin_read_ILAT() & (1 << IRQ_CORETMR))
+	    && (offset < (100000 / HZ / 2)))
+		offset += (USEC_PER_SEC / HZ);
+
+	return offset;
+}
+
+static inline int set_rtc_mmss(unsigned long nowtime)
+{
+	return 0;
+}
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+#ifdef CONFIG_CORE_TIMER_IRQ_L1
+irqreturn_t timer_interrupt(int irq, void *dummy)__attribute__((l1_text));
+#endif
+
+irqreturn_t timer_interrupt(int irq, void *dummy)
+{
+	/* last time the cmos clock got updated */
+	static long last_rtc_update = 0;
+
+	write_seqlock(&xtime_lock);
+
+	do_timer(1);
+	do_leds();
+
+#ifndef CONFIG_SMP
+	update_process_times(user_mode(get_irq_regs()));
+#endif
+	profile_tick(CPU_PROFILING);
+
+	/*
+	 * If we have an externally synchronized Linux clock, then update
+	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+	 * called as close as possible to 500 ms before the new second starts.
+	 */
+
+	if (ntp_synced() &&
+	    xtime.tv_sec > last_rtc_update + 660 &&
+	    (xtime.tv_nsec / NSEC_PER_USEC) >=
+	    500000 - ((unsigned)TICK_SIZE) / 2
+	    && (xtime.tv_nsec / NSEC_PER_USEC) <=
+	    500000 + ((unsigned)TICK_SIZE) / 2) {
+		if (set_rtc_mmss(xtime.tv_sec) == 0)
+			last_rtc_update = xtime.tv_sec;
+		else
+			/* Do it again in 60s. */
+			last_rtc_update = xtime.tv_sec - 600;
+	}
+	write_sequnlock(&xtime_lock);
+	return IRQ_HANDLED;
+}
+
+void __init time_init(void)
+{
+	time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60;	/* 1 Jan 2007 */
+
+#ifdef CONFIG_RTC_DRV_BFIN
+	/* [#2663] hack to filter junk RTC values that would cause
+	 * userspace to have to deal with time values greater than
+	 * 2^31 seconds (which uClibc cannot cope with yet)
+	 */
+	if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
+		printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
+		bfin_write_RTC_STAT(0);
+	}
+#endif
+
+	/* Initialize xtime. From now on, xtime is updated with timer interrupts */
+	xtime.tv_sec = secs_since_1970;
+	xtime.tv_nsec = 0;
+
+	wall_to_monotonic.tv_sec = -xtime.tv_sec;
+
+	time_sched_init(timer_interrupt);
+}
+
+#ifndef CONFIG_GENERIC_TIME
+void do_gettimeofday(struct timeval *tv)
+{
+	unsigned long flags;
+	unsigned long seq;
+	unsigned long usec, sec;
+
+	do {
+		seq = read_seqbegin_irqsave(&xtime_lock, flags);
+		usec = gettimeoffset();
+		sec = xtime.tv_sec;
+		usec += (xtime.tv_nsec / NSEC_PER_USEC);
+	}
+	while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
+
+	while (usec >= USEC_PER_SEC) {
+		usec -= USEC_PER_SEC;
+		sec++;
+	}
+
+	tv->tv_sec = sec;
+	tv->tv_usec = usec;
+}
+EXPORT_SYMBOL(do_gettimeofday);
+
+int do_settimeofday(struct timespec *tv)
+{
+	time_t wtm_sec, sec = tv->tv_sec;
+	long wtm_nsec, nsec = tv->tv_nsec;
+
+	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+		return -EINVAL;
+
+	write_seqlock_irq(&xtime_lock);
+	/*
+	 * This is revolting. We need to set the xtime.tv_usec
+	 * correctly. However, the value in this location is
+	 * is value at the last tick.
+	 * Discover what correction gettimeofday
+	 * would have done, and then undo it!
+	 */
+	nsec -= (gettimeoffset() * NSEC_PER_USEC);
+
+	wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
+	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
+
+	set_normalized_timespec(&xtime, sec, nsec);
+	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
+
+	ntp_clear();
+
+	write_sequnlock_irq(&xtime_lock);
+	clock_was_set();
+
+	return 0;
+}
+EXPORT_SYMBOL(do_settimeofday);
+#endif /* !CONFIG_GENERIC_TIME */
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+	return (unsigned long long)jiffies *(NSEC_PER_SEC / HZ);
+}