[PATCH] efi: clocksoure: make sure the meassured frequency is valid

[Michael Olbrich]

Some EFI implementations have a even slower tick rate and the meassured
frequency may be zero.

Signed-off-by: Michael Olbrich <m.olbrich at pengutronix.de>
Acked-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
 drivers/clocksource/efi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/clocksource/efi.c b/drivers/clocksource/efi.c
index 89906c452eb7..fb5b7ca63de9 100644
--- a/drivers/clocksource/efi.c
+++ b/drivers/clocksource/efi.c
@@ -71,6 +71,10 @@ static int efi_cs_init(struct clocksource *cs)
 		uint64_t nb_100ns;
 
 		freq = ticks_freq_x86();
+		if (freq == 0) {
+			BS->close_event(efi_cs_evt);
+			return -ENODEV;
+		}
 		nb_100ns = 10 * 1000 * 1000 / freq;
 		pr_warn("EFI Event timer too slow freq = %llu Hz\n", freq);
 		efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, nb_100ns);
-- 
2.11.0