File 26183-x86-HPET-masking.patch of Package xen

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File 26183-x86-HPET-masking.patch of Package xen

# HG changeset patch
# User Jan Beulich <jbeulich@suse.com>
# Date 1353575003 -3600
# Node ID c139ca92edca2fab8ec95deb7fd9e4246c3fe28d
# Parent  af6b72a224e99a4a516fbc2eecc06ada569304e8
x86/HPET: fix FSB interrupt masking

HPET_TN_FSB is not really suitable for masking interrupts - it merely
switches between the two delivery methods. The right way of masking is
through the HPET_TN_ENABLE bit (which really is an interrupt enable,
not a counter enable or some such). This is even more so with certain
chip sets not even allowing HPET_TN_FSB to be cleared on some of the
channels.

Further, all the setup of the channel should happen before actually
enabling the interrupt, which requires splitting legacy and FSB logic.

Finally this also fixes an S3 resume problem (HPET_TN_FSB did not get
set in hpet_broadcast_resume(), and hpet_msi_unmask() doesn't get
called from the general resume code either afaict).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -236,7 +236,7 @@ static void hpet_msi_unmask(struct irq_d
     struct hpet_event_channel *ch = desc->action->dev_id;
 
     cfg = hpet_read32(HPET_Tn_CFG(ch->idx));
-    cfg |= HPET_TN_FSB;
+    cfg |= HPET_TN_ENABLE;
     hpet_write32(cfg, HPET_Tn_CFG(ch->idx));
 }
 
@@ -246,7 +246,7 @@ static void hpet_msi_mask(struct irq_des
     struct hpet_event_channel *ch = desc->action->dev_id;
 
     cfg = hpet_read32(HPET_Tn_CFG(ch->idx));
-    cfg &= ~HPET_TN_FSB;
+    cfg &= ~HPET_TN_ENABLE;
     hpet_write32(cfg, HPET_Tn_CFG(ch->idx));
 }
 
@@ -319,8 +319,14 @@ static void __hpet_setup_msi_irq(struct 
 static int __init hpet_setup_msi_irq(unsigned int irq, struct hpet_event_channel *ch)
 {
     int ret;
+    u32 cfg = hpet_read32(HPET_Tn_CFG(ch->idx));
     irq_desc_t *desc = irq_to_desc(irq);
 
+    /* set HPET Tn as oneshot */
+    cfg &= ~(HPET_TN_LEVEL | HPET_TN_PERIODIC);
+    cfg |= HPET_TN_FSB | HPET_TN_32BIT;
+    hpet_write32(cfg, HPET_Tn_CFG(ch->idx));
+
     desc->handler = &hpet_msi_type;
     ret = request_irq(irq, hpet_interrupt_handler, 0, "HPET", ch);
     if ( ret < 0 )
@@ -541,11 +547,14 @@ void __init hpet_broadcast_init(void)
 
     for ( i = 0; i < n; i++ )
     {
-        /* set HPET Tn as oneshot */
-        cfg = hpet_read32(HPET_Tn_CFG(hpet_events[i].idx));
-        cfg &= ~(HPET_TN_LEVEL | HPET_TN_PERIODIC);
-        cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
-        hpet_write32(cfg, HPET_Tn_CFG(hpet_events[i].idx));
+        if ( i == 0 && (cfg & HPET_CFG_LEGACY) )
+        {
+            /* set HPET T0 as oneshot */
+            cfg = hpet_read32(HPET_Tn_CFG(0));
+            cfg &= ~(HPET_TN_LEVEL | HPET_TN_PERIODIC);
+            cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
+            hpet_write32(cfg, HPET_Tn_CFG(0));
+        }
 
         /*
          * The period is a femto seconds value. We need to calculate the scaled
@@ -602,6 +611,8 @@ void hpet_broadcast_resume(void)
         cfg = hpet_read32(HPET_Tn_CFG(hpet_events[i].idx));
         cfg &= ~(HPET_TN_LEVEL | HPET_TN_PERIODIC);
         cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
+        if ( !(hpet_events[i].flags & HPET_EVT_LEGACY) )
+            cfg |= HPET_TN_FSB;
         hpet_write32(cfg, HPET_Tn_CFG(hpet_events[i].idx));
 
         hpet_events[i].next_event = STIME_MAX;

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File 26183-x86-HPET-masking.patch of Package xen

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