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/* Copyright 2016 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "common.h"
#include "console.h"
#include "init_chip.h"
#include "registers.h"
void init_jittery_clock(int highsec)
{
unsigned trimfast = GR_FUSE(RC_JTR_OSC60_CC_TRIM);
unsigned trim48 = GR_FUSE(RC_JTR_OSC48_CC_TRIM);
unsigned delta = (trim48 - trimfast);
/* for metastability reasons, avoid clk_jtr ~= clk_timer, make
* a keepout region around 24MHz of about 0.75MHz, about 3/16 of the
* the delta from trimfast and trim48 */
unsigned skiplow = (trim48 << 4) - (delta * 6);
unsigned skiphigh = (trim48 << 4) + (delta * 6);
unsigned setting = trimfast << 4;
unsigned stepx16;
unsigned bankval;
int bank;
if (highsec)
stepx16 = 0xff - trimfast;
else
stepx16 = 2 * (trim48 - trimfast);
for (bank = 0; bank < 16; bank++) {
/* saturate at 0xff */
bankval = (setting > 0xfff) ? 0xff : (setting >> 4);
GR_XO_JTR_JITTERY_TRIM_BANK(bank) = bankval;
setting += stepx16;
if ((setting > skiplow) && (setting < skiphigh))
setting = skiphigh;
}
GWRITE_FIELD(XO, CLK_JTR_TRIM_CTRL, RC_COARSE_TRIM_SRC, 2);
GWRITE_FIELD(XO, CLK_JTR_TRIM_CTRL, RC_INITIAL_TRIM_PERIOD, 100);
GWRITE_FIELD(XO, CLK_JTR_TRIM_CTRL, RC_TRIM_EN, 1);
GREG32(XO, CLK_JTR_JITTERY_TRIM_EN) = 1;
GREG32(XO, CLK_JTR_SYNC_CONTENTS) = 0;
/* Writing any value locks things until the next hard reboot */
GREG32(XO, CFG_WR_EN) = 0;
GREG32(XO, JTR_CTRL_EN) = 0;
}
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