From 11aaf1f42ad8035c2870dc50852437f5e8863061 Mon Sep 17 00:00:00 2001 From: Vadim Bendebury Date: Fri, 23 May 2014 14:18:35 -0700 Subject: [PATCH] ipq8064: Add work around for slow timer clock Libpayload libc requires timer clock frequency to be at least 1MHz. Ipq8064 code presently provides a single option of 32kHz. Pretend to be running at 1 MHz without additional accuracy. This is a hack which will be reverted as soon as the SOC is configured to supply a faster running clock. BUG=chrome-os-partner:27784, chrome-os-partner:28880 TEST=with other changes depthcharge boots to the CLI console Original-Change-Id: I80ec6652bc5693a549668cd6e824e9cf5c26b182 Original-Signed-off-by: Vadim Bendebury Original-Reviewed-on: https://chromium-review.googlesource.com/201342 Original-Reviewed-by: David Hendricks (cherry picked from commit 466a59967b13986099106f8b44924648c1e6e6cd) Signed-off-by: Marc Jones Change-Id: I113689191db70710e7a45ccd02d672f482343e35 Reviewed-on: http://review.coreboot.org/8004 Reviewed-by: Stefan Reinauer Tested-by: build bot (Jenkins) --- payloads/libpayload/drivers/timer/ipq806x.c | 22 +++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/payloads/libpayload/drivers/timer/ipq806x.c b/payloads/libpayload/drivers/timer/ipq806x.c index 4edbf8eda0..0d70a86813 100644 --- a/payloads/libpayload/drivers/timer/ipq806x.c +++ b/payloads/libpayload/drivers/timer/ipq806x.c @@ -29,13 +29,31 @@ #include +/* + * TODO(vbendeb): reverted this hack once proper timer code is in place (see + * http://crosbug.com/p/28880 for details. + */ +#define MIN_TIMER_FREQ 1000000 + uint64_t timer_hz(void) { - return CONFIG_LP_IPQ806X_TIMER_FREQ; + return (CONFIG_LP_IPQ806X_TIMER_FREQ >= MIN_TIMER_FREQ) ? + CONFIG_LP_IPQ806X_TIMER_FREQ : MIN_TIMER_FREQ; } uint64_t timer_raw_value(void) { - return readl((void *)CONFIG_LP_IPQ806X_TIMER_REG); + uint64_t rawv = readl((void *)CONFIG_LP_IPQ806X_TIMER_REG); + + /* + * This is extremely crude, but it kicks in only for the case when the + * timer clock frequency is below 1MHz, which should never be the case + * on a properly configured system. The compiler will eliminate the + * check as long as config value exceeds 1MHz. + */ + if (CONFIG_LP_IPQ806X_TIMER_FREQ < MIN_TIMER_FREQ) + rawv *= (MIN_TIMER_FREQ / CONFIG_LP_IPQ806X_TIMER_FREQ); + + return rawv; }