sparc32, leon: Remove separate "ticker" timer for SMP

This reduces the need from two timers to one timer.

Moreover, without this patch, when the "ticker" timer triggers timer_cs_read via
tick_periodic it reads the value of the usual timer it can get an wrapped timer
value without timer_cs_internal_counter having been updated leading to the clock
going backwards. This effectively hangs one cpu that gets stuck in
update_wall_time with an offset slightly smaller than 0xffffffffffffffff.

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 37 deletions

diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index 7c0231dabe44..b7c68976cbc7 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -38,7 +38,6 @@ static DEFINE_SPINLOCK(leon_irq_lock);
 
 unsigned long leon3_gptimer_irq; /* interrupt controller irq number */
 unsigned long leon3_gptimer_idx; /* Timer Index (0..6) within Timer Core */
-int leon3_ticker_irq; /* Timer ticker IRQ */
 unsigned int sparc_leon_eirq;
 #define LEON_IMASK(cpu) (&leon3_irqctrl_regs->mask[cpu])
 #define LEON_IACK (&leon3_irqctrl_regs->iclear)
@@ -278,6 +277,9 @@ irqreturn_t leon_percpu_timer_ce_interrupt(int irq, void *unused)
 
         leon_clear_profile_irq(cpu);
 
+        if (cpu == boot_cpu_id)
+                timer_interrupt(irq, NULL);
+
         ce = &per_cpu(sparc32_clockevent, cpu);
 
         irq_enter();
@@ -299,6 +301,7 @@ void __init leon_init_timers(void)
         int icsel;
         int ampopts;
         int err;
+        u32 config;
 
         sparc_config.get_cycles_offset = leon_cycles_offset;
         sparc_config.cs_period = 1000000 / HZ;
@@ -377,23 +380,6 @@ void __init leon_init_timers(void)
         LEON3_BYPASS_STORE_PA(
                         &leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl, 0);
 
-#ifdef CONFIG_SMP
-        leon3_ticker_irq = leon3_gptimer_irq + 1 + leon3_gptimer_idx;
-
-        if (!(LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->config) &
-              (1<<LEON3_GPTIMER_SEPIRQ))) {
-                printk(KERN_ERR "timer not configured with separate irqs\n");
-                BUG();
-        }
-
-        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].val,
-                                0);
-        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].rld,
-                                (((1000000/HZ) - 1)));
-        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].ctrl,
-                                0);
-#endif
-
         /*
          * The IRQ controller may (if implemented) consist of multiple
          * IRQ controllers, each mapped on a 4Kb boundary.
@@ -416,13 +402,6 @@ void __init leon_init_timers(void)
         if (eirq != 0)
                 leon_eirq_setup(eirq);
 
-        irq = _leon_build_device_irq(NULL, leon3_gptimer_irq+leon3_gptimer_idx);
-        err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
-        if (err) {
-                printk(KERN_ERR "unable to attach timer IRQ%d\n", irq);
-                prom_halt();
-        }
-
 #ifdef CONFIG_SMP
         {
                 unsigned long flags;
@@ -439,30 +418,31 @@ void __init leon_init_timers(void)
         }
 #endif
 
-        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
-                              LEON3_GPTIMER_EN |
-                              LEON3_GPTIMER_RL |
-                              LEON3_GPTIMER_LD |
-                              LEON3_GPTIMER_IRQEN);
+        config = LEON3_BYPASS_LOAD_PA(&leon3_gptimer_regs->config);
+        if (config & (1 << LEON3_GPTIMER_SEPIRQ))
+                leon3_gptimer_irq += leon3_gptimer_idx;
+        else if ((config & LEON3_GPTIMER_TIMERS) > 1)
+                pr_warn("GPTIMER uses shared irqs, using other timers of the same core will fail.\n");
 
 #ifdef CONFIG_SMP
         /* Install per-cpu IRQ handler for broadcasted ticker */
-        irq = leon_build_device_irq(leon3_ticker_irq, handle_percpu_irq,
+        irq = leon_build_device_irq(leon3_gptimer_irq, handle_percpu_irq,
                                     "per-cpu", 0);
         err = request_irq(irq, leon_percpu_timer_ce_interrupt,
-                          IRQF_PERCPU | IRQF_TIMER, "ticker",
-                          NULL);
+                          IRQF_PERCPU | IRQF_TIMER, "timer", NULL);
+#else
+        irq = _leon_build_device_irq(NULL, leon3_gptimer_irq);
+        err = request_irq(irq, timer_interrupt, IRQF_TIMER, "timer", NULL);
+#endif
         if (err) {
-                printk(KERN_ERR "unable to attach ticker IRQ%d\n", irq);
+                pr_err("Unable to attach timer IRQ%d\n", irq);
                 prom_halt();
         }
-
-        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx+1].ctrl,
+        LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[leon3_gptimer_idx].ctrl,
                               LEON3_GPTIMER_EN |
                               LEON3_GPTIMER_RL |
                               LEON3_GPTIMER_LD |
                               LEON3_GPTIMER_IRQEN);
-#endif
         return;
 bad:
         printk(KERN_ERR "No Timer/irqctrl found\n");