LXR uboot/arch/arm/mach-omap2/abb.c

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Adaptive Body Bias programming sequence for OMAP family
   4 *
   5 * (C) Copyright 2013
   6 * Texas Instruments, <www.ti.com>
   7 *
   8 * Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
   9 */
  10
  11#include <common.h>
  12#include <asm/omap_common.h>
  13#include <asm/arch/clock.h>
  14#include <asm/io.h>
  15#include <asm/arch/sys_proto.h>
  16
  17__weak s8 abb_setup_ldovbb(u32 fuse, u32 ldovbb)
  18{
  19        return -1;
  20}
  21
  22static void abb_setup_timings(u32 setup)
  23{
  24        u32 sys_rate, sr2_cnt, clk_cycles;
  25
  26        /*
  27         * SR2_WTCNT_VALUE is the settling time for the ABB ldo after a
  28         * transition and must be programmed with the correct time at boot.
  29         * The value programmed into the register is the number of SYS_CLK
  30         * clock cycles that match a given wall time profiled for the ldo.
  31         * This value depends on:
  32         * settling time of ldo in micro-seconds (varies per OMAP family),
  33         * of clock cycles per SYS_CLK period (varies per OMAP family),
  34         * the SYS_CLK frequency in MHz (varies per board)
  35         * The formula is:
  36         *
  37         *                     ldo settling time (in micro-seconds)
  38         * SR2_WTCNT_VALUE = ------------------------------------------
  39         *                  (# system clock cycles) * (sys_clk period)
  40         *
  41         * Put another way:
  42         *
  43         * SR2_WTCNT_VALUE = settling time / (# SYS_CLK cycles / SYS_CLK rate))
  44         *
  45         * To avoid dividing by zero multiply both "# clock cycles" and
  46         * "settling time" by 10 such that the final result is the one we want.
  47         */
  48
  49        /* calculate SR2_WTCNT_VALUE */
  50        sys_rate = DIV_ROUND_CLOSEST(V_OSCK, 1000000);
  51        clk_cycles = DIV_ROUND_CLOSEST(OMAP_ABB_CLOCK_CYCLES * 10, sys_rate);
  52        sr2_cnt = DIV_ROUND_CLOSEST(OMAP_ABB_SETTLING_TIME * 10, clk_cycles);
  53
  54        setbits_le32(setup,
  55                     sr2_cnt << (ffs(OMAP_ABB_SETUP_SR2_WTCNT_VALUE_MASK) - 1));
  56}
  57
  58void abb_setup(u32 fuse, u32 ldovbb, u32 setup, u32 control,
  59               u32 txdone, u32 txdone_mask, u32 opp)
  60{
  61        u32 abb_type_mask, opp_sel_mask;
  62
  63        /* sanity check */
  64        if (!setup || !control || !txdone)
  65                return;
  66
  67        /* setup ABB only in case of Fast or Slow OPP */
  68        switch (opp) {
  69        case OMAP_ABB_FAST_OPP:
  70                abb_type_mask = OMAP_ABB_SETUP_ACTIVE_FBB_SEL_MASK;
  71                opp_sel_mask = OMAP_ABB_CONTROL_FAST_OPP_SEL_MASK;
  72                break;
  73        case OMAP_ABB_SLOW_OPP:
  74                abb_type_mask = OMAP_ABB_SETUP_ACTIVE_RBB_SEL_MASK;
  75                opp_sel_mask = OMAP_ABB_CONTROL_SLOW_OPP_SEL_MASK;
  76                break;
  77        default:
  78               return;
  79        }
  80
  81        /*
  82         * For some OMAP silicons additional setup for LDOVBB register is
  83         * required. This is determined by data retrieved from corresponding
  84         * OPP EFUSE register. Data, which is retrieved from EFUSE - is
  85         * ABB enable/disable flag and VSET value, which must be copied
  86         * to LDOVBB register. If function call fails - return quietly,
  87         * it means no ABB is required for such silicon.
  88         *
  89         * For silicons, which don't require LDOVBB setup "fuse" and
  90         * "ldovbb" offsets are not defined. ABB will be initialized in
  91         * the common way for them.
  92         */
  93        if (fuse && ldovbb) {
  94                if (abb_setup_ldovbb(fuse, ldovbb))
  95                        return;
  96        }
  97
  98        /* clear ABB registers */
  99        writel(0, setup);
 100        writel(0, control);
 101
 102        /* configure timings, based on oscillator value */
 103        abb_setup_timings(setup);
 104
 105        /* clear pending interrupts before setup */
 106        setbits_le32(txdone, txdone_mask);
 107
 108        /* select ABB type */
 109        setbits_le32(setup, abb_type_mask | OMAP_ABB_SETUP_SR2EN_MASK);
 110
 111        /* initiate ABB ldo change */
 112        setbits_le32(control, opp_sel_mask | OMAP_ABB_CONTROL_OPP_CHANGE_MASK);
 113
 114        /* wait until transition complete */
 115        if (!wait_on_value(txdone_mask, txdone_mask, (void *)txdone, LDELAY))
 116                puts("Error: ABB txdone is not set\n");
 117
 118        /* clear ABB tranxdone */
 119        setbits_le32(txdone, txdone_mask);
 120}
 121