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/*
*
* Adaptive Body Bias programming sequence for OMAP family
*
* (C) Copyright 2013
* Texas Instruments, <www.ti.com>
*
* Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
#include <common.h>
#include <asm/omap_common.h>
#include <asm/io.h>
#include <asm/arch/sys_proto.h>
__weak s8 abb_setup_ldovbb(u32 fuse, u32 ldovbb)
{
return -1;
}
static void abb_setup_timings(u32 setup)
{
u32 sys_rate, sr2_cnt, clk_cycles;
/*
* SR2_WTCNT_VALUE is the settling time for the ABB ldo after a
* transition and must be programmed with the correct time at boot.
* The value programmed into the register is the number of SYS_CLK
* clock cycles that match a given wall time profiled for the ldo.
* This value depends on:
* settling time of ldo in micro-seconds (varies per OMAP family),
* of clock cycles per SYS_CLK period (varies per OMAP family),
* the SYS_CLK frequency in MHz (varies per board)
* The formula is:
*
* ldo settling time (in micro-seconds)
* SR2_WTCNT_VALUE = ------------------------------------------
* (# system clock cycles) * (sys_clk period)
*
* Put another way:
*
* SR2_WTCNT_VALUE = settling time / (# SYS_CLK cycles / SYS_CLK rate))
*
* To avoid dividing by zero multiply both "# clock cycles" and
* "settling time" by 10 such that the final result is the one we want.
*/
/* calculate SR2_WTCNT_VALUE */
sys_rate = DIV_ROUND(V_OSCK, 1000000);
clk_cycles = DIV_ROUND(OMAP_ABB_CLOCK_CYCLES * 10, sys_rate);
sr2_cnt = DIV_ROUND(OMAP_ABB_SETTLING_TIME * 10, clk_cycles);
setbits_le32(setup,
sr2_cnt << (ffs(OMAP_ABB_SETUP_SR2_WTCNT_VALUE_MASK) - 1));
}
void abb_setup(u32 fuse, u32 ldovbb, u32 setup, u32 control,
u32 txdone, u32 txdone_mask, u32 opp)
{
u32 abb_type_mask, opp_sel_mask;
/* sanity check */
if (!setup || !control || !txdone)
return;
/* setup ABB only in case of Fast or Slow OPP */
switch (opp) {
case OMAP_ABB_FAST_OPP:
abb_type_mask = OMAP_ABB_SETUP_ACTIVE_FBB_SEL_MASK;
opp_sel_mask = OMAP_ABB_CONTROL_FAST_OPP_SEL_MASK;
break;
case OMAP_ABB_SLOW_OPP:
abb_type_mask = OMAP_ABB_SETUP_ACTIVE_RBB_SEL_MASK;
opp_sel_mask = OMAP_ABB_CONTROL_SLOW_OPP_SEL_MASK;
break;
default:
return;
}
/*
* For some OMAP silicons additional setup for LDOVBB register is
* required. This is determined by data retrieved from corresponding
* OPP EFUSE register. Data, which is retrieved from EFUSE - is
* ABB enable/disable flag and VSET value, which must be copied
* to LDOVBB register. If function call fails - return quietly,
* it means no ABB is required for such silicon.
*
* For silicons, which don't require LDOVBB setup "fuse" and
* "ldovbb" offsets are not defined. ABB will be initialized in
* the common way for them.
*/
if (fuse && ldovbb) {
if (abb_setup_ldovbb(fuse, ldovbb))
return;
}
/* clear ABB registers */
writel(0, setup);
writel(0, control);
/* configure timings, based on oscillator value */
abb_setup_timings(setup);
/* clear pending interrupts before setup */
setbits_le32(txdone, txdone_mask);
/* select ABB type */
setbits_le32(setup, abb_type_mask | OMAP_ABB_SETUP_SR2EN_MASK);
/* initiate ABB ldo change */
setbits_le32(control, opp_sel_mask | OMAP_ABB_CONTROL_OPP_CHANGE_MASK);
/* wait until transition complete */
if (!wait_on_value(txdone_mask, txdone_mask, (void *)txdone, LDELAY))
puts("Error: ABB txdone is not set\n");
/* clear ABB tranxdone */
setbits_le32(txdone, txdone_mask);
}
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