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temp: ipq8064: work around for slow timer clock

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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

Change-Id: I80ec6652bc5693a549668cd6e824e9cf5c26b182
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/201342
Reviewed-by: David Hendricks <dhendrix@chromium.org>
This commit is contained in:
Vadim Bendebury 2014-05-23 14:18:35 -07:00 • committed by chrome-internal-fetch
commit 466a59967b
1 changed files with 20 additions and 2 deletions
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22
payloads/libpayload/drivers/timer/ipq806x.c
View file

@ -29,13 +29,31 @@
#include <libpayload.h>
/*
* 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;
}