powerpc: Fix event-scan code for 32-bit CHRP

On CHRP machines we are supposed to call into firmware (RTAS)
periodically, to give it a chance to check for errors and other
events.  Under ppc we had some special code in timer_interrupt
to do this, but that didn't get transferred over to arch/powerpc.
Instead, we use an array of timer_list structs, one per CPU,
and use add_timer_on to make sure each one gets called on the
appropriate CPU.

With this we can remove the heartbeat_* elements of the ppc_md
struct.

Signed-off-by: Paul Mackerras <paulus@samba.org>

2 files changed, 46 insertions, 20 deletions

diff --git a/arch/powerpc/platforms/chrp/chrp.h b/arch/powerpc/platforms/chrp/chrp.h
index 814f54742e0f..63f0aee4c158 100644
--- a/arch/powerpc/platforms/chrp/chrp.h
+++ b/arch/powerpc/platforms/chrp/chrp.h
@@ -8,4 +8,4 @@ extern int chrp_set_rtc_time(struct rtc_time *);
 extern long chrp_time_init(void);
 
 extern void chrp_find_bridges(void);
-extern void chrp_event_scan(void);
+extern void chrp_event_scan(unsigned long);
diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index 8bf4307e323d..9c718bb2305e 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -35,6 +35,7 @@
 #include <linux/root_dev.h>
 #include <linux/initrd.h>
 #include <linux/module.h>
+#include <linux/timer.h>
 
 #include <asm/io.h>
 #include <asm/pgtable.h>
@@ -61,6 +62,10 @@ EXPORT_SYMBOL(_chrp_type);
 
 struct mpic *chrp_mpic;
 
+/* Used for doing CHRP event-scans */
+DEFINE_PER_CPU(struct timer_list, heartbeat_timer);
+unsigned long event_scan_interval;
+
 /*
  * XXX this should be in xmon.h, but putting it there means xmon.h
  * has to include <linux/interrupt.h> (to get irqreturn_t), which
@@ -229,8 +234,6 @@ void __init chrp_setup_arch(void)
 {
         struct device_node *root = find_path_device ("/");
         char *machine = NULL;
-        struct device_node *device;
-        unsigned int *p = NULL;
 
         /* init to some ~sane value until calibrate_delay() runs */
         loops_per_jiffy = 50000000/HZ;
@@ -287,21 +290,6 @@ void __init chrp_setup_arch(void)
          */
         sio_init();
 
-        /* Get the event scan rate for the rtas so we know how
-         * often it expects a heartbeat. -- Cort
-         */
-        device = find_devices("rtas");
-        if (device)
-                p = (unsigned int *) get_property
-                        (device, "rtas-event-scan-rate", NULL);
-        if (p && *p) {
-                ppc_md.heartbeat = chrp_event_scan;
-                ppc_md.heartbeat_reset = HZ / (*p * 30) - 1;
-                ppc_md.heartbeat_count = 1;
-                printk("RTAS Event Scan Rate: %u (%lu jiffies)\n",
-                       *p, ppc_md.heartbeat_reset);
-        }
-
         pci_create_OF_bus_map();
 
         /*
@@ -312,7 +300,7 @@ void __init chrp_setup_arch(void)
 }
 
 void
-chrp_event_scan(void)
+chrp_event_scan(unsigned long unused)
 {
         unsigned char log[1024];
         int ret = 0;
@@ -320,7 +308,8 @@ chrp_event_scan(void)
         /* XXX: we should loop until the hardware says no more error logs -- Cort */
         rtas_call(rtas_token("event-scan"), 4, 1, &ret, 0xffffffff, 0,
                   __pa(log), 1024);
-        ppc_md.heartbeat_count = ppc_md.heartbeat_reset;
+        mod_timer(&__get_cpu_var(heartbeat_timer),
+                  jiffies + event_scan_interval);
 }
 
 /*
@@ -465,6 +454,9 @@ void __init chrp_init_IRQ(void)
 void __init
 chrp_init2(void)
 {
+        struct device_node *device;
+        unsigned int *p = NULL;
+
 #ifdef CONFIG_NVRAM
         chrp_nvram_init();
 #endif
@@ -476,6 +468,40 @@ chrp_init2(void)
         request_region(0x80,0x10,"dma page reg");
         request_region(0xc0,0x20,"dma2");
 
+        /* Get the event scan rate for the rtas so we know how
+         * often it expects a heartbeat. -- Cort
+         */
+        device = find_devices("rtas");
+        if (device)
+                p = (unsigned int *) get_property
+                        (device, "rtas-event-scan-rate", NULL);
+        if (p && *p) {
+                /*
+                 * Arrange to call chrp_event_scan at least *p times
+                 * per minute.  We use 59 rather than 60 here so that
+                 * the rate will be slightly higher than the minimum.
+                 * This all assumes we don't do hotplug CPU on any
+                 * machine that needs the event scans done.
+                 */
+                unsigned long interval, offset;
+                int cpu, ncpus;
+                struct timer_list *timer;
+
+                interval = HZ * 59 / *p;
+                offset = HZ;
+                ncpus = num_online_cpus();
+                event_scan_interval = ncpus * interval;
+                for (cpu = 0; cpu < ncpus; ++cpu) {
+                        timer = &per_cpu(heartbeat_timer, cpu);
+                        setup_timer(timer, chrp_event_scan, 0);
+                        timer->expires = jiffies + offset;
+                        add_timer_on(timer, cpu);
+                        offset += interval;
+                }
+                printk("RTAS Event Scan Rate: %u (%lu jiffies)\n",
+                       *p, interval);
+        }
+
         if (ppc_md.progress)
                 ppc_md.progress("  Have fun!    ", 0x7777);
 }