[MIPS] time: SMP-proofing of Sibyte clockevent/clocksource code.
Ralf Baechle [Mon, 22 Oct 2007 09:38:44 +0000 (10:38 +0100)]
The BCM148 has 4 cores but there are also just 4 generic timers available
so use the ZBbus cycle counter instead of it.  In addition the ZBbus
counter also offers a much higher resolution and 64-bit counting so I'm
considering a later complete conversion to it once I figure out if all
members of the Sibyte SOC family support it - the docs seem to agree but
the headers files seem to disagree ...

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/sibyte/bcm1480/irq.c
arch/mips/sibyte/bcm1480/smp.c
arch/mips/sibyte/bcm1480/time.c
arch/mips/sibyte/sb1250/irq.c
arch/mips/sibyte/sb1250/smp.c
arch/mips/sibyte/sb1250/time.c
include/asm-mips/sibyte/sb1250.h

index 7aa79bf..10299ba 100644 (file)
@@ -452,6 +452,43 @@ static void bcm1480_kgdb_interrupt(void)
 
 extern void bcm1480_mailbox_interrupt(void);
 
+static inline void dispatch_ip4(void)
+{
+       int cpu = smp_processor_id();
+       int irq = K_BCM1480_INT_TIMER_0 + cpu;
+
+       /* Reset the timer */
+       __raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS,
+                   IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
+
+       do_IRQ(irq);
+}
+
+static inline void dispatch_ip2(void)
+{
+       unsigned long long mask_h, mask_l;
+       unsigned int cpu = smp_processor_id();
+       unsigned long base;
+
+       /*
+        * Default...we've hit an IP[2] interrupt, which means we've got to
+        * check the 1480 interrupt registers to figure out what to do.  Need
+        * to detect which CPU we're on, now that smp_affinity is supported.
+        */
+       base = A_BCM1480_IMR_MAPPER(cpu);
+       mask_h = __raw_readq(
+               IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_H));
+       mask_l = __raw_readq(
+               IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_L));
+
+       if (mask_h) {
+               if (mask_h ^ 1)
+                       do_IRQ(fls64(mask_h) - 1);
+               else if (mask_l)
+                       do_IRQ(63 + fls64(mask_l));
+       }
+}
+
 asmlinkage void plat_irq_dispatch(void)
 {
        unsigned int pending;
@@ -469,17 +506,8 @@ asmlinkage void plat_irq_dispatch(void)
        else
 #endif
 
-       if (pending & CAUSEF_IP4) {
-               int cpu = smp_processor_id();
-               int irq = K_BCM1480_INT_TIMER_0 + cpu;
-
-               /* Reset the timer */
-               __raw_writeq(M_SCD_TIMER_ENABLE|M_SCD_TIMER_MODE_CONTINUOUS,
-                           IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
-
-               do_IRQ(irq);
-       }
-
+       if (pending & CAUSEF_IP4)
+               dispatch_ip4();
 #ifdef CONFIG_SMP
        else if (pending & CAUSEF_IP3)
                bcm1480_mailbox_interrupt();
@@ -490,27 +518,6 @@ asmlinkage void plat_irq_dispatch(void)
                bcm1480_kgdb_interrupt();               /* KGDB (uart 1) */
 #endif
 
-       else if (pending & CAUSEF_IP2) {
-               unsigned long long mask_h, mask_l;
-               unsigned long base;
-
-               /*
-                * Default...we've hit an IP[2] interrupt, which means we've
-                * got to check the 1480 interrupt registers to figure out what
-                * to do.  Need to detect which CPU we're on, now that
-                * smp_affinity is supported.
-                */
-               base = A_BCM1480_IMR_MAPPER(smp_processor_id());
-               mask_h = __raw_readq(
-                       IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_H));
-               mask_l = __raw_readq(
-                       IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_L));
-
-               if (mask_h) {
-                       if (mask_h ^ 1)
-                               do_IRQ(fls64(mask_h) - 1);
-                       else
-                               do_IRQ(63 + fls64(mask_l));
-               }
-       }
+       else if (pending & CAUSEF_IP2)
+               dispatch_ip2();
 }
index 02b266a..436ba78 100644 (file)
@@ -58,7 +58,7 @@ static void *mailbox_0_regs[] = {
 /*
  * SMP init and finish on secondary CPUs
  */
-void bcm1480_smp_init(void)
+void __cpuinit bcm1480_smp_init(void)
 {
        unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
                STATUSF_IP1 | STATUSF_IP0;
@@ -67,7 +67,7 @@ void bcm1480_smp_init(void)
        change_c0_status(ST0_IM, imask);
 }
 
-void bcm1480_smp_finish(void)
+void __cpuinit bcm1480_smp_finish(void)
 {
        extern void sb1480_clockevent_init(void);
 
index c730744..610f025 100644 (file)
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  */
-
-/*
- * These are routines to set up and handle interrupts from the
- * bcm1480 general purpose timer 0.  We're using the timer as a
- * system clock, so we set it up to run at 100 Hz.  On every
- * interrupt, we update our idea of what the time of day is,
- * then call do_timer() in the architecture-independent kernel
- * code to do general bookkeeping (e.g. update jiffies, run
- * bottom halves, etc.)
- */
 #include <linux/clockchips.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <linux/percpu.h>
 #include <linux/spinlock.h>
 
-#include <asm/irq.h>
 #include <asm/addrspace.h>
 #include <asm/time.h>
 #include <asm/io.h>
 #define IMR_IP3_VAL    K_BCM1480_INT_MAP_I1
 #define IMR_IP4_VAL    K_BCM1480_INT_MAP_I2
 
-#ifdef CONFIG_SIMULATION
-#define BCM1480_HPT_VALUE      50000
-#else
-#define BCM1480_HPT_VALUE      1000000
-#endif
-
 extern int bcm1480_steal_irq(int irq);
 
-void __init plat_time_init(void)
-{
-       unsigned int cpu = smp_processor_id();
-       unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
-
-       BUG_ON(cpu > 3);        /* Only have 4 general purpose timers */
-
-       bcm1480_mask_irq(cpu, irq);
-
-       /* Map the timer interrupt to ip[4] of this cpu */
-       __raw_writeq(IMR_IP4_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H)
-             + (irq<<3)));
-
-       bcm1480_unmask_irq(cpu, irq);
-       bcm1480_steal_irq(irq);
-}
-
 /*
- * The general purpose timer ticks at 1 Mhz independent if
+ * The general purpose timer ticks at 1MHz independent if
  * the rest of the system
  */
 static void sibyte_set_mode(enum clock_event_mode mode,
@@ -88,7 +55,7 @@ static void sibyte_set_mode(enum clock_event_mode mode,
        switch (mode) {
        case CLOCK_EVT_MODE_PERIODIC:
                __raw_writeq(0, timer_cfg);
-               __raw_writeq(BCM1480_HPT_VALUE / HZ - 1, timer_init);
+               __raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, timer_init);
                __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
                             timer_cfg);
                break;
@@ -121,80 +88,96 @@ static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
        return res;
 }
 
-static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
-
 static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
 {
        unsigned int cpu = smp_processor_id();
-       struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
+       struct clock_event_device *cd = dev_id;
+       void __iomem *timer_cfg;
+
+       timer_cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
 
        /* Reset the timer */
        __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
-                    IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
+                    timer_cfg);
        cd->event_handler(cd);
 
        return IRQ_HANDLED;
 }
 
-static struct irqaction sibyte_counter_irqaction = {
-       .handler        = sibyte_counter_handler,
-       .flags          = IRQF_DISABLED | IRQF_PERCPU,
-       .name           = "timer",
-};
+static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
+static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
+static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
 
-/*
- * This interrupt is "special" in that it doesn't use the request_irq
- * way to hook the irq line.  The timer interrupt is initialized early
- * enough to make this a major pain, and it's also firing enough to
- * warrant a bit of special case code.  bcm1480_timer_interrupt is
- * called directly from irq_handler.S when IP[4] is set during an
- * interrupt
- */
 void __cpuinit sb1480_clockevent_init(void)
 {
        unsigned int cpu = smp_processor_id();
        unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
+       struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
        struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
+       unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
+
+       BUG_ON(cpu > 3);        /* Only have 4 general purpose timers */
 
-       cd->name                = "bcm1480-counter";
+       sprintf(name, "bcm1480-counter %d", cpu);
+       cd->name                = name;
        cd->features            = CLOCK_EVT_FEAT_PERIODIC |
                                  CLOCK_EVT_MODE_ONESHOT;
+       clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
+       cd->max_delta_ns        = clockevent_delta2ns(0x7fffff, cd);
+       cd->min_delta_ns        = clockevent_delta2ns(1, cd);
+       cd->rating              = 200;
+       cd->irq                 = irq;
+       cd->cpumask             = cpumask_of_cpu(cpu);
        cd->set_next_event      = sibyte_next_event;
        cd->set_mode            = sibyte_set_mode;
-       cd->irq                 = irq;
-       clockevent_set_clock(cd, BCM1480_HPT_VALUE);
+       clockevents_register_device(cd);
+
+       bcm1480_mask_irq(cpu, irq);
+
+       /*
+        * Map timer interrupt to IP[4] of this cpu
+        */
+       __raw_writeq(IMR_IP4_VAL,
+                    IOADDR(A_BCM1480_IMR_REGISTER(cpu,
+                       R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) + (irq << 3)));
 
-       setup_irq(irq, &sibyte_counter_irqaction);
+       bcm1480_unmask_irq(cpu, irq);
+       bcm1480_steal_irq(irq);
+
+       action->handler = sibyte_counter_handler;
+       action->flags   = IRQF_DISABLED | IRQF_PERCPU;
+       action->name    = name;
+       action->dev_id  = cd;
+       setup_irq(irq, action);
 }
 
 static cycle_t bcm1480_hpt_read(void)
 {
-       /* We assume this function is called xtime_lock held. */
-       unsigned long count =
-               __raw_readq(IOADDR(A_SCD_TIMER_REGISTER(0, R_SCD_TIMER_CNT)));
-       return (jiffies + 1) * (BCM1480_HPT_VALUE / HZ) - count;
+       return (cycle_t) __raw_readq(IOADDR(A_SCD_ZBBUS_CYCLE_COUNT));
 }
 
 struct clocksource bcm1480_clocksource = {
-       .name   = "MIPS",
+       .name   = "zbbus-cycles",
        .rating = 200,
        .read   = bcm1480_hpt_read,
-       .mask   = CLOCKSOURCE_MASK(32),
-       .shift  = 32,
+       .mask   = CLOCKSOURCE_MASK(64),
        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 void __init sb1480_clocksource_init(void)
 {
        struct clocksource *cs = &bcm1480_clocksource;
+       unsigned int plldiv;
+       unsigned long zbbus;
 
-       clocksource_set_clock(cs, BCM1480_HPT_VALUE);
+       plldiv = G_BCM1480_SYS_PLL_DIV(__raw_readq(IOADDR(A_SCD_SYSTEM_CFG)));
+       zbbus = ((plldiv >> 1) * 50000000) + ((plldiv & 1) * 25000000);
+       clocksource_set_clock(cs, zbbus);
        clocksource_register(cs);
 }
 
-void __init bcm1480_hpt_setup(void)
+void __init plat_time_init(void)
 {
-       mips_hpt_frequency = BCM1480_HPT_VALUE;
        sb1480_clocksource_init();
        sb1480_clockevent_init();
 }
index 500d17e..53780a1 100644 (file)
@@ -402,6 +402,22 @@ static void sb1250_kgdb_interrupt(void)
 
 extern void sb1250_mailbox_interrupt(void);
 
+static inline void dispatch_ip2(void)
+{
+       unsigned int cpu = smp_processor_id();
+       unsigned long long mask;
+
+       /*
+        * Default...we've hit an IP[2] interrupt, which means we've got to
+        * check the 1250 interrupt registers to figure out what to do.  Need
+        * to detect which CPU we're on, now that smp_affinity is supported.
+        */
+       mask = __raw_readq(IOADDR(A_IMR_REGISTER(cpu,
+                                 R_IMR_INTERRUPT_STATUS_BASE)));
+       if (mask)
+               do_IRQ(fls64(mask) - 1);
+}
+
 asmlinkage void plat_irq_dispatch(void)
 {
        unsigned int cpu = smp_processor_id();
@@ -434,21 +450,8 @@ asmlinkage void plat_irq_dispatch(void)
                sb1250_kgdb_interrupt();
 #endif
 
-       else if (pending & CAUSEF_IP2) {
-               unsigned long long mask;
-
-               /*
-                * Default...we've hit an IP[2] interrupt, which means we've
-                * got to check the 1250 interrupt registers to figure out what
-                * to do.  Need to detect which CPU we're on, now that
-                * smp_affinity is supported.
-                */
-               mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
-                                             R_IMR_INTERRUPT_STATUS_BASE)));
-               if (mask)
-                       do_IRQ(fls64(mask) - 1);
-               else
-                       spurious_interrupt();
-       } else
+       else if (pending & CAUSEF_IP2)
+               dispatch_ip2();
+       else
                spurious_interrupt();
 }
index aaa4f30..3f52c95 100644 (file)
@@ -46,7 +46,7 @@ static void *mailbox_regs[] = {
 /*
  * SMP init and finish on secondary CPUs
  */
-void sb1250_smp_init(void)
+void __cpuinit sb1250_smp_init(void)
 {
        unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
                STATUSF_IP1 | STATUSF_IP0;
@@ -55,7 +55,7 @@ void sb1250_smp_init(void)
        change_c0_status(ST0_IM, imask);
 }
 
-void sb1250_smp_finish(void)
+void __cpuinit sb1250_smp_finish(void)
 {
        extern void sb1250_clockevent_init(void);
 
index 9ef5462..a41e908 100644 (file)
 
 extern int sb1250_steal_irq(int irq);
 
-static cycle_t sb1250_hpt_read(void);
-
-void __init sb1250_hpt_setup(void)
-{
-       int cpu = smp_processor_id();
-
-       if (!cpu) {
-               /* Setup hpt using timer #3 but do not enable irq for it */
-               __raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
-               __raw_writeq(SB1250_HPT_VALUE,
-                            IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_INIT)));
-               __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
-                            IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
-
-               mips_hpt_frequency = V_SCD_TIMER_FREQ;
-               clocksource_mips.read = sb1250_hpt_read;
-               clocksource_mips.mask = M_SCD_TIMER_INIT;
-       }
-}
-
 /*
  * The general purpose timer ticks at 1 Mhz independent if
  * the rest of the system
@@ -121,18 +101,14 @@ sibyte_next_event(unsigned long delta, struct clock_event_device *evt)
        return 0;
 }
 
-struct clock_event_device sibyte_hpt_clockevent = {
-       .name           = "sb1250-counter",
-       .features       = CLOCK_EVT_FEAT_PERIODIC,
-       .set_mode       = sibyte_set_mode,
-       .set_next_event = sibyte_next_event,
-       .shift          = 32,
-       .irq            = 0,
-};
-
 static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
 {
-       struct clock_event_device *cd = &sibyte_hpt_clockevent;
+       unsigned int cpu = smp_processor_id();
+       struct clock_event_device *cd = dev_id;
+
+       /* ACK interrupt */
+       ____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
+                      IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
 
        cd->event_handler(cd);
 
@@ -145,15 +121,35 @@ static struct irqaction sibyte_irqaction = {
        .name           = "timer",
 };
 
+static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
+static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
+static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
+
 void __cpuinit sb1250_clockevent_init(void)
 {
-       struct clock_event_device *cd = &sibyte_hpt_clockevent;
        unsigned int cpu = smp_processor_id();
-       int irq = K_INT_TIMER_0 + cpu;
+       unsigned int irq = K_INT_TIMER_0 + cpu;
+       struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
+       struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
+       unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
 
        /* Only have 4 general purpose timers, and we use last one as hpt */
        BUG_ON(cpu > 2);
 
+       sprintf(name, "bcm1480-counter %d", cpu);
+       cd->name                = name;
+       cd->features            = CLOCK_EVT_FEAT_PERIODIC |
+                                 CLOCK_EVT_MODE_ONESHOT;
+       clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
+       cd->max_delta_ns        = clockevent_delta2ns(0x7fffff, cd);
+       cd->min_delta_ns        = clockevent_delta2ns(1, cd);
+       cd->rating              = 200;
+       cd->irq                 = irq;
+       cd->cpumask             = cpumask_of_cpu(cpu);
+       cd->set_next_event      = sibyte_next_event;
+       cd->set_mode            = sibyte_set_mode;
+       clockevents_register_device(cd);
+
        sb1250_mask_irq(cpu, irq);
 
        /* Map the timer interrupt to ip[4] of this cpu */
@@ -165,17 +161,11 @@ void __cpuinit sb1250_clockevent_init(void)
        sb1250_unmask_irq(cpu, irq);
        sb1250_steal_irq(irq);
 
-       /*
-        * This interrupt is "special" in that it doesn't use the request_irq
-        * way to hook the irq line.  The timer interrupt is initialized early
-        * enough to make this a major pain, and it's also firing enough to
-        * warrant a bit of special case code.  sb1250_timer_interrupt is
-        * called directly from irq_handler.S when IP[4] is set during an
-        * interrupt
-        */
+       action->handler = sibyte_counter_handler;
+       action->flags   = IRQF_DISABLED | IRQF_PERCPU;
+       action->name    = name;
+       action->dev_id  = cd;
        setup_irq(irq, &sibyte_irqaction);
-
-       clockevents_register_device(cd);
 }
 
 /*
@@ -195,8 +185,7 @@ struct clocksource bcm1250_clocksource = {
        .name   = "MIPS",
        .rating = 200,
        .read   = sb1250_hpt_read,
-       .mask   = CLOCKSOURCE_MASK(32),
-       .shift  = 32,
+       .mask   = CLOCKSOURCE_MASK(23),
        .flags  = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
@@ -204,6 +193,17 @@ void __init sb1250_clocksource_init(void)
 {
        struct clocksource *cs = &bcm1250_clocksource;
 
+       /* Setup hpt using timer #3 but do not enable irq for it */
+       __raw_writeq(0,
+                    IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
+                                                R_SCD_TIMER_CFG)));
+       __raw_writeq(SB1250_HPT_VALUE,
+                    IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
+                                                R_SCD_TIMER_INIT)));
+       __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
+                    IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM,
+                                                R_SCD_TIMER_CFG)));
+
        clocksource_set_clock(cs, V_SCD_TIMER_FREQ);
        clocksource_register(cs);
 }
index 494aa65..0dad844 100644 (file)
@@ -45,13 +45,11 @@ extern unsigned int soc_type;
 extern unsigned int periph_rev;
 extern unsigned int zbbus_mhz;
 
-extern void sb1250_hpt_setup(void);
 extern void sb1250_time_init(void);
 extern void sb1250_mask_irq(int cpu, int irq);
 extern void sb1250_unmask_irq(int cpu, int irq);
 extern void sb1250_smp_finish(void);
 
-extern void bcm1480_hpt_setup(void);
 extern void bcm1480_time_init(void);
 extern void bcm1480_mask_irq(int cpu, int irq);
 extern void bcm1480_unmask_irq(int cpu, int irq);