[ARM] 4303/3: base kernel support for TI DaVinci

Add base kernel support for the TI DaVinci platform.

This patch only includes interrupts, timers, CPU identification,
serial support and basic power and sleep controller init.  More
drivers to come.

Signed-off-by: Kevin Hilman <khilman@mvista.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 372 insertions, 0 deletions

diff --git a/arch/arm/mach-davinci/time.c b/arch/arm/mach-davinci/time.c
new file mode 100644
index 000000000000..4d8425de6922
--- /dev/null
+++ b/arch/arm/mach-davinci/time.c
@@ -0,0 +1,372 @@
+/*
+ * DaVinci timer subsystem
+ *
+ * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/spinlock.h>
+
+#include <asm/io.h>
+#include <asm/hardware.h>
+#include <asm/system.h>
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+#include <asm/mach/time.h>
+#include <asm/errno.h>
+#include <asm/arch/io.h>
+
+static struct clock_event_device clockevent_davinci;
+
+#define DAVINCI_TIMER0_BASE (IO_PHYS + 0x21400)
+#define DAVINCI_TIMER1_BASE (IO_PHYS + 0x21800)
+#define DAVINCI_WDOG_BASE   (IO_PHYS + 0x21C00)
+
+enum {
+        T0_BOT = 0, T0_TOP, T1_BOT, T1_TOP, NUM_TIMERS,
+};
+
+#define IS_TIMER1(id)    (id & 0x2)
+#define IS_TIMER0(id)    (!IS_TIMER1(id))
+#define IS_TIMER_TOP(id) ((id & 0x1))
+#define IS_TIMER_BOT(id) (!IS_TIMER_TOP(id))
+
+static int timer_irqs[NUM_TIMERS] = {
+        IRQ_TINT0_TINT12,
+        IRQ_TINT0_TINT34,
+        IRQ_TINT1_TINT12,
+        IRQ_TINT1_TINT34,
+};
+
+/*
+ * This driver configures the 2 64-bit count-up timers as 4 independent
+ * 32-bit count-up timers used as follows:
+ *
+ * T0_BOT: Timer 0, bottom:  clockevent source for hrtimers
+ * T0_TOP: Timer 0, top   :  clocksource for generic timekeeping
+ * T1_BOT: Timer 1, bottom:  (used by DSP in TI DSPLink code)
+ * T1_TOP: Timer 1, top   :  <unused>
+ */
+#define TID_CLOCKEVENT  T0_BOT
+#define TID_CLOCKSOURCE T0_TOP
+
+/* Timer register offsets */
+#define PID12                        0x0
+#define TIM12                        0x10
+#define TIM34                        0x14
+#define PRD12                        0x18
+#define PRD34                        0x1c
+#define TCR                          0x20
+#define TGCR                         0x24
+#define WDTCR                        0x28
+
+/* Timer register bitfields */
+#define TCR_ENAMODE_DISABLE          0x0
+#define TCR_ENAMODE_ONESHOT          0x1
+#define TCR_ENAMODE_PERIODIC         0x2
+#define TCR_ENAMODE_MASK             0x3
+
+#define TGCR_TIMMODE_SHIFT           2
+#define TGCR_TIMMODE_64BIT_GP        0x0
+#define TGCR_TIMMODE_32BIT_UNCHAINED 0x1
+#define TGCR_TIMMODE_64BIT_WDOG      0x2
+#define TGCR_TIMMODE_32BIT_CHAINED   0x3
+
+#define TGCR_TIM12RS_SHIFT           0
+#define TGCR_TIM34RS_SHIFT           1
+#define TGCR_RESET                   0x0
+#define TGCR_UNRESET                 0x1
+#define TGCR_RESET_MASK              0x3
+
+#define WDTCR_WDEN_SHIFT             14
+#define WDTCR_WDEN_DISABLE           0x0
+#define WDTCR_WDEN_ENABLE            0x1
+#define WDTCR_WDKEY_SHIFT            16
+#define WDTCR_WDKEY_SEQ0             0xa5c6
+#define WDTCR_WDKEY_SEQ1             0xda7e
+
+struct timer_s {
+        char *name;
+        unsigned int id;
+        unsigned long period;
+        unsigned long opts;
+        unsigned long reg_base;
+        unsigned long tim_reg;
+        unsigned long prd_reg;
+        unsigned long enamode_shift;
+        struct irqaction irqaction;
+};
+static struct timer_s timers[];
+
+/* values for 'opts' field of struct timer_s */
+#define TIMER_OPTS_DISABLED   0x00
+#define TIMER_OPTS_ONESHOT    0x01
+#define TIMER_OPTS_PERIODIC   0x02
+
+static int timer32_config(struct timer_s *t)
+{
+        u32 tcr = davinci_readl(t->reg_base + TCR);
+
+        /* disable timer */
+        tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
+        davinci_writel(tcr, t->reg_base + TCR);
+
+        /* reset counter to zero, set new period */
+        davinci_writel(0, t->tim_reg);
+        davinci_writel(t->period, t->prd_reg);
+
+        /* Set enable mode */
+        if (t->opts & TIMER_OPTS_ONESHOT) {
+                tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift;
+        } else if (t->opts & TIMER_OPTS_PERIODIC) {
+                tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift;
+        }
+
+        davinci_writel(tcr, t->reg_base + TCR);
+        return 0;
+}
+
+static inline u32 timer32_read(struct timer_s *t)
+{
+        return davinci_readl(t->tim_reg);
+}
+
+static irqreturn_t timer_interrupt(int irq, void *dev_id)
+{
+        struct clock_event_device *evt = &clockevent_davinci;
+
+        evt->event_handler(evt);
+        return IRQ_HANDLED;
+}
+
+/* called when 32-bit counter wraps */
+static irqreturn_t freerun_interrupt(int irq, void *dev_id)
+{
+        return IRQ_HANDLED;
+}
+
+static struct timer_s timers[] = {
+        [TID_CLOCKEVENT] = {
+                .name      = "clockevent",
+                .opts      = TIMER_OPTS_DISABLED,
+                .irqaction = {
+                        .flags   = IRQF_DISABLED | IRQF_TIMER,
+                        .handler = timer_interrupt,
+                }
+        },
+        [TID_CLOCKSOURCE] = {
+                .name       = "free-run counter",
+                .period     = ~0,
+                .opts       = TIMER_OPTS_PERIODIC,
+                .irqaction = {
+                        .flags   = IRQF_DISABLED | IRQF_TIMER,
+                        .handler = freerun_interrupt,
+                }
+        },
+};
+
+static void __init timer_init(void)
+{
+        u32 bases[] = {DAVINCI_TIMER0_BASE, DAVINCI_TIMER1_BASE};
+        int i;
+
+        /* Global init of each 64-bit timer as a whole */
+        for(i=0; i<2; i++) {
+                u32 tgcr, base = bases[i];
+
+                /* Disabled, Internal clock source */
+                davinci_writel(0, base + TCR);
+
+                /* reset both timers, no pre-scaler for timer34 */
+                tgcr = 0;
+                davinci_writel(tgcr, base + TGCR);
+
+                /* Set both timers to unchained 32-bit */
+                tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
+                davinci_writel(tgcr, base + TGCR);
+
+                /* Unreset timers */
+                tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
+                        (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
+                davinci_writel(tgcr, base + TGCR);
+
+                /* Init both counters to zero */
+                davinci_writel(0, base + TIM12);
+                davinci_writel(0, base + TIM34);
+        }
+
+        /* Init of each timer as a 32-bit timer */
+        for (i=0; i< ARRAY_SIZE(timers); i++) {
+                struct timer_s *t = &timers[i];
+
+                if (t->name) {
+                        t->id = i;
+                        t->reg_base = (IS_TIMER1(t->id) ?
+                               DAVINCI_TIMER1_BASE : DAVINCI_TIMER0_BASE);
+
+                        if (IS_TIMER_BOT(t->id)) {
+                                t->enamode_shift = 6;
+                                t->tim_reg = t->reg_base + TIM12;
+                                t->prd_reg = t->reg_base + PRD12;
+                        } else {
+                                t->enamode_shift = 22;
+                                t->tim_reg = t->reg_base + TIM34;
+                                t->prd_reg = t->reg_base + PRD34;
+                        }
+
+                        /* Register interrupt */
+                        t->irqaction.name = t->name;
+                        t->irqaction.dev_id = (void *)t;
+                        if (t->irqaction.handler != NULL) {
+                                setup_irq(timer_irqs[t->id], &t->irqaction);
+                        }
+
+                        timer32_config(&timers[i]);
+                }
+        }
+}
+
+/*
+ * clocksource
+ */
+static cycle_t read_cycles(void)
+{
+        struct timer_s *t = &timers[TID_CLOCKSOURCE];
+
+        return (cycles_t)timer32_read(t);
+}
+
+static struct clocksource clocksource_davinci = {
+        .name           = "timer0_1",
+        .rating         = 300,
+        .read           = read_cycles,
+        .mask           = CLOCKSOURCE_MASK(32),
+        .shift          = 24,
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+
+/*
+ * clockevent
+ */
+static int davinci_set_next_event(unsigned long cycles,
+                                  struct clock_event_device *evt)
+{
+        struct timer_s *t = &timers[TID_CLOCKEVENT];
+
+        t->period = cycles;
+        timer32_config(t);
+        return 0;
+}
+
+static void davinci_set_mode(enum clock_event_mode mode,
+                             struct clock_event_device *evt)
+{
+        struct timer_s *t = &timers[TID_CLOCKEVENT];
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+                t->period = CLOCK_TICK_RATE / (HZ);
+                t->opts = TIMER_OPTS_PERIODIC;
+                timer32_config(t);
+                break;
+        case CLOCK_EVT_MODE_ONESHOT:
+                t->opts = TIMER_OPTS_ONESHOT;
+                break;
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+                t->opts = TIMER_OPTS_DISABLED;
+                break;
+        }
+}
+
+static struct clock_event_device clockevent_davinci = {
+        .name           = "timer0_0",
+        .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+        .shift          = 32,
+        .set_next_event = davinci_set_next_event,
+        .set_mode       = davinci_set_mode,
+};
+
+
+static void __init davinci_timer_init(void)
+{
+        static char err[] __initdata = KERN_ERR
+                "%s: can't register clocksource!\n";
+
+        /* init timer hw */
+        timer_init();
+
+        /* setup clocksource */
+        clocksource_davinci.mult =
+                clocksource_khz2mult(CLOCK_TICK_RATE/1000,
+                                     clocksource_davinci.shift);
+        if (clocksource_register(&clocksource_davinci))
+                printk(err, clocksource_davinci.name);
+
+        /* setup clockevent */
+        clockevent_davinci.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC,
+                                         clockevent_davinci.shift);
+        clockevent_davinci.max_delta_ns =
+                clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
+        clockevent_davinci.min_delta_ns =
+                clockevent_delta2ns(1, &clockevent_davinci);
+
+        clockevent_davinci.cpumask = cpumask_of_cpu(0);
+        clockevents_register_device(&clockevent_davinci);
+}
+
+struct sys_timer davinci_timer = {
+        .init   = davinci_timer_init,
+};
+
+
+/* reset board using watchdog timer */
+void davinci_watchdog_reset(void) {
+        u32 tgcr, wdtcr, base = DAVINCI_WDOG_BASE;
+
+        /* disable, internal clock source */
+        davinci_writel(0, base + TCR);
+
+        /* reset timer, set mode to 64-bit watchdog, and unreset */
+        tgcr = 0;
+        davinci_writel(tgcr, base + TCR);
+        tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
+        tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
+                (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
+        davinci_writel(tgcr, base + TCR);
+
+        /* clear counter and period regs */
+        davinci_writel(0, base + TIM12);
+        davinci_writel(0, base + TIM34);
+        davinci_writel(0, base + PRD12);
+        davinci_writel(0, base + PRD34);
+
+        /* enable */
+        wdtcr = davinci_readl(base + WDTCR);
+        wdtcr |= WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT;
+        davinci_writel(wdtcr, base + WDTCR);
+
+        /* put watchdog in pre-active state */
+        wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
+                (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
+        davinci_writel(wdtcr, base + WDTCR);
+
+        /* put watchdog in active state */
+        wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
+                (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
+        davinci_writel(wdtcr, base + WDTCR);
+
+        /* write an invalid value to the WDKEY field to trigger
+         * a watchdog reset */
+        wdtcr = 0x00004000;
+        davinci_writel(wdtcr, base + WDTCR);
+}