[IA64] avoid broken SAL_CACHE_FLUSH implementations

If SAL_CACHE_FLUSH drops interrupts, complain about it and fall back to
using PAL_CACHE_FLUSH instead.

This is to work around a defect in HP rx5670 firmware: when an interrupt
occurs during SAL_CACHE_FLUSH, SAL drops the interrupt but leaves it marked
"in-service", which leaves the interrupt (and others of equal or lower
priority) masked.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 75 insertions, 0 deletions

diff --git a/arch/ia64/kernel/sal.c b/arch/ia64/kernel/sal.c
index acc0f132f86c..056f7a6eedc7 100644
--- a/arch/ia64/kernel/sal.c
+++ b/arch/ia64/kernel/sal.c
@@ -14,6 +14,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 
+#include <asm/delay.h>
 #include <asm/page.h>
 #include <asm/sal.h>
 #include <asm/pal.h>
@@ -214,6 +215,78 @@ chk_nointroute_opt(void)
 static void __init sal_desc_ap_wakeup(void *p) { }
 #endif
 
+/*
+ * HP rx5670 firmware polls for interrupts during SAL_CACHE_FLUSH by reading
+ * cr.ivr, but it never writes cr.eoi.  This leaves any interrupt marked as
+ * "in-service" and masks other interrupts of equal or lower priority.
+ *
+ * HP internal defect reports: F1859, F2775, F3031.
+ */
+static int sal_cache_flush_drops_interrupts;
+
+static void __init
+check_sal_cache_flush (void)
+{
+        unsigned long flags, itv;
+        int cpu;
+        u64 vector;
+
+        cpu = get_cpu();
+        local_irq_save(flags);
+
+        /*
+         * Schedule a timer interrupt, wait until it's reported, and see if
+         * SAL_CACHE_FLUSH drops it.
+         */
+        itv = ia64_get_itv();
+        BUG_ON((itv & (1 << 16)) == 0);
+
+        ia64_set_itv(IA64_TIMER_VECTOR);
+        ia64_set_itm(ia64_get_itc() + 1000);
+
+        while (!ia64_get_irr(IA64_TIMER_VECTOR))
+                cpu_relax();
+
+        ia64_sal_cache_flush(3);
+
+        if (ia64_get_irr(IA64_TIMER_VECTOR)) {
+                vector = ia64_get_ivr();
+                ia64_eoi();
+                WARN_ON(vector != IA64_TIMER_VECTOR);
+        } else {
+                sal_cache_flush_drops_interrupts = 1;
+                printk(KERN_ERR "SAL: SAL_CACHE_FLUSH drops interrupts; "
+                        "PAL_CACHE_FLUSH will be used instead\n");
+                ia64_eoi();
+        }
+
+        ia64_set_itv(itv);
+        local_irq_restore(flags);
+        put_cpu();
+}
+
+s64
+ia64_sal_cache_flush (u64 cache_type)
+{
+        struct ia64_sal_retval isrv;
+
+        if (sal_cache_flush_drops_interrupts) {
+                unsigned long flags;
+                u64 progress;
+                s64 rc;
+
+                progress = 0;
+                local_irq_save(flags);
+                rc = ia64_pal_cache_flush(cache_type,
+                        PAL_CACHE_FLUSH_INVALIDATE, &progress, NULL);
+                local_irq_restore(flags);
+                return rc;
+        }
+
+        SAL_CALL(isrv, SAL_CACHE_FLUSH, cache_type, 0, 0, 0, 0, 0, 0);
+        return isrv.status;
+}
+
 void __init
 ia64_sal_init (struct ia64_sal_systab *systab)
 {
@@ -262,6 +335,8 @@ ia64_sal_init (struct ia64_sal_systab *systab)
                 }
                 p += SAL_DESC_SIZE(*p);
         }
+
+        check_sal_cache_flush();
 }
 
 int