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authorDavid S. Miller <davem@davemloft.net>2008-09-16 17:11:43 -0400
committerDavid S. Miller <davem@davemloft.net>2008-09-16 17:11:43 -0400
commit2e57572a50a4de41c6cbc879a4866a312d4cd316 (patch)
treec4f58ec96c06642c4b415b881d3f0a3b673d5b44 /arch/x86/kernel/hpet.c
parent9b2e43ae4e9609f80034dfe8de895045cac52d77 (diff)
parentf948cc6ab9e61a8e88d70ee9aafc690e6d26f92c (diff)
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/sparc-2.6
Conflicts: arch/sparc64/kernel/pci_psycho.c
Diffstat (limited to 'arch/x86/kernel/hpet.c')
-rw-r--r--arch/x86/kernel/hpet.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 59fd3b6b1303..73deaffadd03 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -210,8 +210,8 @@ static void hpet_legacy_clockevent_register(void)
210 /* Calculate the min / max delta */ 210 /* Calculate the min / max delta */
211 hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, 211 hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
212 &hpet_clockevent); 212 &hpet_clockevent);
213 hpet_clockevent.min_delta_ns = clockevent_delta2ns(0x30, 213 /* 5 usec minimum reprogramming delta. */
214 &hpet_clockevent); 214 hpet_clockevent.min_delta_ns = 5000;
215 215
216 /* 216 /*
217 * Start hpet with the boot cpu mask and make it 217 * Start hpet with the boot cpu mask and make it
@@ -270,15 +270,22 @@ static void hpet_legacy_set_mode(enum clock_event_mode mode,
270} 270}
271 271
272static int hpet_legacy_next_event(unsigned long delta, 272static int hpet_legacy_next_event(unsigned long delta,
273 struct clock_event_device *evt) 273 struct clock_event_device *evt)
274{ 274{
275 unsigned long cnt; 275 u32 cnt;
276 276
277 cnt = hpet_readl(HPET_COUNTER); 277 cnt = hpet_readl(HPET_COUNTER);
278 cnt += delta; 278 cnt += (u32) delta;
279 hpet_writel(cnt, HPET_T0_CMP); 279 hpet_writel(cnt, HPET_T0_CMP);
280 280
281 return ((long)(hpet_readl(HPET_COUNTER) - cnt ) > 0) ? -ETIME : 0; 281 /*
282 * We need to read back the CMP register to make sure that
283 * what we wrote hit the chip before we compare it to the
284 * counter.
285 */
286 WARN_ON((u32)hpet_readl(HPET_T0_CMP) != cnt);
287
288 return (s32)((u32)hpet_readl(HPET_COUNTER) - cnt) >= 0 ? -ETIME : 0;
282} 289}
283 290
284/* 291/*