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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 <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/201342
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
(cherry picked from commit 466a59967b13986099106f8b44924648c1e6e6cd)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I113689191db70710e7a45ccd02d672f482343e35
Reviewed-on: http://review.coreboot.org/8004
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins)
This commit is contained in:
Vadim Bendebury 2014-05-23 14:18:35 -07:00 committed by Marc Jones
parent 66fdbced5e
commit 11aaf1f42a
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;
}