Signed-off-by: Graeme Russ gruss@tss-engineering.com ---
arch/arm/cpu/arm926ejs/mxs/spl_boot.c | 1 + arch/arm/cpu/arm926ejs/mxs/spl_lradc_init.c | 13 +++- arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c | 18 +++++ arch/arm/cpu/arm926ejs/mxs/spl_power_init.c | 100 +++++++++++++++++++++++++++- 4 files changed, 127 insertions(+), 5 deletions(-)
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_boot.c b/arch/arm/cpu/arm926ejs/mxs/spl_boot.c index d29b9aa..2a5f817 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_boot.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_boot.c @@ -147,6 +147,7 @@ void mxs_common_spl_init(const uint32_t arg, const uint32_t *resptr, mxs_iomux_setup_multiple_pads(iomux_setup, iomux_size);
mxs_spl_console_init(); + debug("SPL: Serial Console Initialised\n");
mxs_power_init();
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_lradc_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_lradc_init.c index cdfcddd..9e6f24a 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_lradc_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_lradc_init.c @@ -18,6 +18,8 @@ void mxs_lradc_init(void) { struct mxs_lradc_regs *regs = (struct mxs_lradc_regs *)MXS_LRADC_BASE;
+ debug("SPL: Initialisating LRADC"); + writel(LRADC_CTRL0_SFTRST, ®s->hw_lradc_ctrl0_clr); writel(LRADC_CTRL0_CLKGATE, ®s->hw_lradc_ctrl0_clr); writel(LRADC_CTRL0_ONCHIP_GROUNDREF, ®s->hw_lradc_ctrl0_clr); @@ -37,9 +39,15 @@ void mxs_lradc_enable_batt_measurement(void) { struct mxs_lradc_regs *regs = (struct mxs_lradc_regs *)MXS_LRADC_BASE;
+ debug("SPL: Enabling LRADC battery measurement\n"); + /* Check if the channel is present at all. */ - if (!(readl(®s->hw_lradc_status) & LRADC_STATUS_CHANNEL7_PRESENT)) + if (!(readl(®s->hw_lradc_status) & LRADC_STATUS_CHANNEL7_PRESENT)) { + debug("SPL: LRADC channel 7 is not present - aborting\n"); return; + } + + debug("SPL: LRADC channel 7 is present - configuring\n");
writel(LRADC_CTRL1_LRADC7_IRQ_EN, ®s->hw_lradc_ctrl1_clr); writel(LRADC_CTRL1_LRADC7_IRQ, ®s->hw_lradc_ctrl1_clr); @@ -65,6 +73,7 @@ void mxs_lradc_enable_batt_measurement(void) 100, ®s->hw_lradc_delay3);
writel(0xffffffff, ®s->hw_lradc_ch7_clr); - writel(LRADC_DELAY_KICK, ®s->hw_lradc_delay3_set); + + debug("SPL: LRADC channel 7 configuration complete\n"); } diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c index 97ef67d..a744e5d 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c @@ -92,6 +92,7 @@ static uint32_t dram_vals[] = {
__weak void mxs_adjust_memory_params(uint32_t *dram_vals) { + debug("SPL: Using default SDRAM parameters\n"); }
#ifdef CONFIG_MX28 @@ -99,8 +100,10 @@ static void initialize_dram_values(void) { int i;
+ debug("SPL: Setting mx28 board specific SDRAM parameters\n"); mxs_adjust_memory_params(dram_vals);
+ debug("SPL: Applying SDRAM parameters\n"); for (i = 0; i < ARRAY_SIZE(dram_vals); i++) writel(dram_vals[i], MXS_DRAM_BASE + (4 * i)); } @@ -109,6 +112,7 @@ static void initialize_dram_values(void) { int i;
+ debug("SPL: Setting mx23 board specific SDRAM parameters\n"); mxs_adjust_memory_params(dram_vals);
/* @@ -120,6 +124,7 @@ static void initialize_dram_values(void) * HW_DRAM_CTL8 is setup as the last element. * So skip the initialization of these HW_DRAM_CTL registers. */ + debug("SPL: Applying SDRAM parameters\n"); for (i = 0; i < ARRAY_SIZE(dram_vals); i++) { if (i == 8 || i == 27 || i == 28 || i == 35) continue; @@ -146,6 +151,8 @@ static void mxs_mem_init_clock(void) const unsigned char divider = 21; #endif
+ debug("SPL: Initialising FRAC0\n"); + /* Gate EMI clock */ writeb(CLKCTRL_FRAC_CLKGATE, &clkctrl_regs->hw_clkctrl_frac0_set[CLKCTRL_FRAC0_EMI]); @@ -170,6 +177,7 @@ static void mxs_mem_init_clock(void) &clkctrl_regs->hw_clkctrl_clkseq_clr);
early_delay(10000); + debug("SPL: FRAC0 Initialised\n"); }
static void mxs_mem_setup_cpu_and_hbus(void) @@ -177,6 +185,8 @@ static void mxs_mem_setup_cpu_and_hbus(void) struct mxs_clkctrl_regs *clkctrl_regs = (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ debug("SPL: Setting CPU and HBUS clock frequencies\n"); + /* Set fractional divider for ref_cpu to 480 * 18 / 19 = 454MHz * and ungate CPU clock */ writeb(19 & CLKCTRL_FRAC_FRAC_MASK, @@ -209,6 +219,8 @@ static void mxs_mem_setup_vdda(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Configuring VDDA\n"); + writel((0xc << POWER_VDDACTRL_TRG_OFFSET) | (0x7 << POWER_VDDACTRL_BO_OFFSET_OFFSET) | POWER_VDDACTRL_LINREG_OFFSET_1STEPS_BELOW, @@ -240,6 +252,8 @@ static void mx23_mem_setup_vddmem(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Setting mx23 VDDMEM\n"); + /* We must wait before and after disabling the current limiter! */ early_delay(10000);
@@ -252,6 +266,8 @@ static void mx23_mem_setup_vddmem(void)
static void mx23_mem_init(void) { + debug("SPL: Initialising mx23 SDRAM Controller\n"); + /* * Reset/ungate the EMI block. This is essential, otherwise the system * suffers from memory instability. This thing is mx23 specific and is @@ -297,6 +313,8 @@ static void mx28_mem_init(void) struct mxs_pinctrl_regs *pinctrl_regs = (struct mxs_pinctrl_regs *)MXS_PINCTRL_BASE;
+ debug("SPL: Initialising mx28 SDRAM Controller\n"); + /* Set DDR2 mode */ writel(PINCTRL_EMI_DS_CTRL_DDR_MODE_DDR2, &pinctrl_regs->hw_pinctrl_emi_ds_ctrl_set); diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index 1c54ab7..7fb734e 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -26,6 +26,8 @@ static void mxs_power_clock2xtal(void) struct mxs_clkctrl_regs *clkctrl_regs = (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ debug("SPL: Switching CPU clock to 24MHz XTAL\n"); + /* Set XTAL as CPU reference clock */ writel(CLKCTRL_CLKSEQ_BYPASS_CPU, &clkctrl_regs->hw_clkctrl_clkseq_set); @@ -43,9 +45,23 @@ static void mxs_power_clock2pll(void) struct mxs_clkctrl_regs *clkctrl_regs = (struct mxs_clkctrl_regs *)MXS_CLKCTRL_BASE;
+ debug("SPL: Switching CPU core clock source to PLL\n"); + + /* + * TODO: Are we really? It looks like we turn on PLL0, but we then + * set the CLKCTRL_CLKSEQ_BYPASS_CPU bit of the (which was already + * set by mxs_power_clock2xtal()). Clearing this bit here seems to + * introduce some instability (causing the CPU core to hang). Maybe + * we aren't giving PLL0 enough time to stabilise? + */ setbits_le32(&clkctrl_regs->hw_clkctrl_pll0ctrl0, CLKCTRL_PLL0CTRL0_POWER); early_delay(100); + + /* + * TODO: Should the PLL0 FORCE_LOCK bit be set here followed be a + * wait on the PLL0 LOCK bit? + */ setbits_le32(&clkctrl_regs->hw_clkctrl_clkseq, CLKCTRL_CLKSEQ_BYPASS_CPU); } @@ -62,6 +78,8 @@ static void mxs_power_set_auto_restart(void) struct mxs_rtc_regs *rtc_regs = (struct mxs_rtc_regs *)MXS_RTC_BASE;
+ debug("SPL: Setting auto-restart bit\n"); + writel(RTC_CTRL_SFTRST, &rtc_regs->hw_rtc_ctrl_clr); while (readl(&rtc_regs->hw_rtc_ctrl) & RTC_CTRL_SFTRST) ; @@ -101,14 +119,17 @@ static void mxs_power_set_linreg(void) (struct mxs_power_regs *)MXS_POWER_BASE;
/* Set linear regulator 25mV below switching converter */ + debug("SPL: Setting VDDD 25mV below DC-DC converters\n"); clrsetbits_le32(&power_regs->hw_power_vdddctrl, POWER_VDDDCTRL_LINREG_OFFSET_MASK, POWER_VDDDCTRL_LINREG_OFFSET_1STEPS_BELOW);
+ debug("SPL: Setting VDDA 25mV below DC-DC converters\n"); clrsetbits_le32(&power_regs->hw_power_vddactrl, POWER_VDDACTRL_LINREG_OFFSET_MASK, POWER_VDDACTRL_LINREG_OFFSET_1STEPS_BELOW);
+ debug("SPL: Setting VDDIO 25mV below DC-DC converters\n"); clrsetbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_LINREG_OFFSET_MASK, POWER_VDDIOCTRL_LINREG_OFFSET_1STEPS_BELOW); @@ -127,6 +148,8 @@ static int mxs_get_batt_volt(void) volt &= POWER_BATTMONITOR_BATT_VAL_MASK; volt >>= POWER_BATTMONITOR_BATT_VAL_OFFSET; volt *= 8; + + debug("SPL: Battery Voltage = %dmV\n", volt); return volt; }
@@ -154,8 +177,10 @@ static int mxs_is_batt_good(void) (struct mxs_power_regs *)MXS_POWER_BASE; uint32_t volt = mxs_get_batt_volt();
- if ((volt >= 2400) && (volt <= 4300)) + if ((volt >= 2400) && (volt <= 4300)) { + debug("SPL: Battery is good\n"); return 1; + }
clrsetbits_le32(&power_regs->hw_power_5vctrl, POWER_5VCTRL_CHARGE_4P2_ILIMIT_MASK, @@ -175,16 +200,21 @@ static int mxs_is_batt_good(void)
volt = mxs_get_batt_volt();
- if (volt >= 3500) + if (volt >= 3500) { + debug("SPL: Battery Voltage too high\n"); return 0; + }
- if (volt >= 2400) + if (volt >= 2400) { + debug("SPL: Battery is good\n"); return 1; + }
writel(POWER_CHARGE_STOP_ILIMIT_MASK | POWER_CHARGE_BATTCHRG_I_MASK, &power_regs->hw_power_charge_clr); writel(POWER_CHARGE_PWD_BATTCHRG, &power_regs->hw_power_charge_set);
+ debug("SPL: Battery Voltage too low\n"); return 0; }
@@ -203,6 +233,7 @@ static void mxs_power_setup_5v_detect(void) (struct mxs_power_regs *)MXS_POWER_BASE;
/* Start 5V detection */ + debug("SPL: Starting 5V input detection comparator\n"); clrsetbits_le32(&power_regs->hw_power_5vctrl, POWER_5VCTRL_VBUSVALID_TRSH_MASK, POWER_5VCTRL_VBUSVALID_TRSH_4V4 | @@ -220,6 +251,8 @@ static void mxs_src_power_init(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Pre-Configuring power block\n"); + /* Improve efficieny and reduce transient ripple */ writel(POWER_LOOPCTRL_TOGGLE_DIF | POWER_LOOPCTRL_EN_CM_HYST | POWER_LOOPCTRL_EN_DF_HYST, &power_regs->hw_power_loopctrl_set); @@ -257,6 +290,8 @@ static void mxs_power_init_4p2_params(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Configuring common 4P2 regulator params\n"); + /* Setup 4P2 parameters */ clrsetbits_le32(&power_regs->hw_power_dcdc4p2, POWER_DCDC4P2_CMPTRIP_MASK | POWER_DCDC4P2_TRG_MASK, @@ -289,6 +324,8 @@ static void mxs_enable_4p2_dcdc_input(int xfer) uint32_t tmp, vbus_thresh, vbus_5vdetect, pwd_bo; uint32_t prev_5v_brnout, prev_5v_droop;
+ debug("SPL: %s 4P2 DC-DC Input\n", xfer ? "Enabling" : "Disabling"); + prev_5v_brnout = readl(&power_regs->hw_power_5vctrl) & POWER_5VCTRL_PWDN_5VBRNOUT; prev_5v_droop = readl(&power_regs->hw_power_ctrl) & @@ -390,6 +427,8 @@ static void mxs_power_init_4p2_regulator(void) (struct mxs_power_regs *)MXS_POWER_BASE; uint32_t tmp, tmp2;
+ debug("SPL: Enabling 4P2 regulator\n"); + setbits_le32(&power_regs->hw_power_dcdc4p2, POWER_DCDC4P2_ENABLE_4P2);
writel(POWER_CHARGE_ENABLE_LOAD, &power_regs->hw_power_charge_set); @@ -407,6 +446,7 @@ static void mxs_power_init_4p2_regulator(void) * gradually to avoid large inrush current from the 5V cable which can * cause transients/problems */ + debug("SPL: Charging 4P2 capacitor\n"); mxs_enable_4p2_dcdc_input(0);
if (readl(&power_regs->hw_power_ctrl) & POWER_CTRL_VBUS_VALID_IRQ) { @@ -420,6 +460,8 @@ static void mxs_power_init_4p2_regulator(void) POWER_DCDC4P2_ENABLE_DCDC); writel(POWER_5VCTRL_PWD_CHARGE_4P2_MASK, &power_regs->hw_power_5vctrl_set); + + debug("SPL: Unable to recover from mx23 errata 5837\n"); hang(); }
@@ -433,6 +475,7 @@ static void mxs_power_init_4p2_regulator(void) * current limit until the brownout status is false or until we've * reached our maximum defined 4p2 current limit. */ + debug("SPL: Setting 4P2 brownout level\n"); clrsetbits_le32(&power_regs->hw_power_dcdc4p2, POWER_DCDC4P2_BO_MASK, 22 << POWER_DCDC4P2_BO_OFFSET); /* 4.15V */ @@ -479,8 +522,11 @@ static void mxs_power_init_dcdc_4p2_source(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Switching DC-DC converters to 4P2\n"); + if (!(readl(&power_regs->hw_power_dcdc4p2) & POWER_DCDC4P2_ENABLE_DCDC)) { + debug("SPL: Already switched - aborting\n"); hang(); }
@@ -509,6 +555,8 @@ static void mxs_power_enable_4p2(void) uint32_t vdddctrl, vddactrl, vddioctrl; uint32_t tmp;
+ debug("SPL: Powering up 4P2 regulator\n"); + vdddctrl = readl(&power_regs->hw_power_vdddctrl); vddactrl = readl(&power_regs->hw_power_vddactrl); vddioctrl = readl(&power_regs->hw_power_vddioctrl); @@ -559,6 +607,8 @@ static void mxs_power_enable_4p2(void) if (tmp) writel(POWER_CHARGE_ENABLE_LOAD, &power_regs->hw_power_charge_clr); + + debug("SPL: 4P2 regulator powered-up\n"); }
/** @@ -574,6 +624,8 @@ static void mxs_boot_valid_5v(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Booting from 5V supply\n"); + /* * Use VBUSVALID level instead of VDD5V_GT_VDDIO level to trigger a 5V * disconnect event. FIXME @@ -601,6 +653,9 @@ static void mxs_powerdown(void) { struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE; + + debug("Powering Down\n"); + writel(POWER_RESET_UNLOCK_KEY, &power_regs->hw_power_reset); writel(POWER_RESET_UNLOCK_KEY | POWER_RESET_PWD_OFF, &power_regs->hw_power_reset); @@ -617,6 +672,8 @@ static void mxs_batt_boot(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Configuring power block to boot from battery\n"); + clrbits_le32(&power_regs->hw_power_5vctrl, POWER_5VCTRL_PWDN_5VBRNOUT); clrbits_le32(&power_regs->hw_power_5vctrl, POWER_5VCTRL_ENABLE_DCDC);
@@ -672,6 +729,8 @@ static void mxs_handle_5v_conflict(void) (struct mxs_power_regs *)MXS_POWER_BASE; uint32_t tmp;
+ debug("SPL: Resolving 5V conflict\n"); + setbits_le32(&power_regs->hw_power_vddioctrl, POWER_VDDIOCTRL_BO_OFFSET_MASK);
@@ -683,19 +742,27 @@ static void mxs_handle_5v_conflict(void) * VDDIO has a brownout, then the VDD5V_GT_VDDIO becomes * unreliable */ + debug("SPL: VDDIO has a brownout\n"); mxs_powerdown(); break; }
if (tmp & POWER_STS_VDD5V_GT_VDDIO) { + debug("SPL: POWER_STS_VDD5V_GT_VDDIO is set\n"); mxs_boot_valid_5v(); break; } else { + debug("SPL: POWER_STS_VDD5V_GT_VDDIO is not set\n"); mxs_powerdown(); break; }
+ /* + * TODO: I can't see this being reached. We'll either + * powerdown or boot from a stable 5V supply. + */ if (tmp & POWER_STS_PSWITCH_MASK) { + debug("SPL: POWER_STS_PSWITCH_MASK is set\n"); mxs_batt_boot(); break; } @@ -713,21 +780,26 @@ static void mxs_5v_boot(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Configuring power block to boot from 5V input\n"); + /* * NOTE: In original IMX-Bootlets, this also checks for VBUSVALID, * but their implementation always returns 1 so we omit it here. */ if (readl(&power_regs->hw_power_sts) & POWER_STS_VDD5V_GT_VDDIO) { + debug("SPL: 5V VDD good\n"); mxs_boot_valid_5v(); return; }
early_delay(1000); if (readl(&power_regs->hw_power_sts) & POWER_STS_VDD5V_GT_VDDIO) { + debug("SPL: 5V VDD good (after delay)\n"); mxs_boot_valid_5v(); return; }
+ debug("SPL: 5V VDD not good\n"); mxs_handle_5v_conflict(); }
@@ -742,6 +814,8 @@ static void mxs_init_batt_bo(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Initialising battery brown-out level to 3.0V\n"); + /* Brownout at 3V */ clrsetbits_le32(&power_regs->hw_power_battmonitor, POWER_BATTMONITOR_BRWNOUT_LVL_MASK, @@ -762,6 +836,8 @@ static void mxs_switch_vddd_to_dcdc_source(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Switching VDDD to DC-DC converters\n"); + clrsetbits_le32(&power_regs->hw_power_vdddctrl, POWER_VDDDCTRL_LINREG_OFFSET_MASK, POWER_VDDDCTRL_LINREG_OFFSET_1STEPS_BELOW); @@ -788,6 +864,8 @@ static void mxs_power_configure_power_source(void) struct mxs_lradc_regs *lradc_regs = (struct mxs_lradc_regs *)MXS_LRADC_BASE;
+ debug("SPL: Configuring power source\n"); + mxs_src_power_init();
if (readl(&power_regs->hw_power_sts) & POWER_STS_VDD5V_GT_VDDIO) { @@ -811,6 +889,10 @@ static void mxs_power_configure_power_source(void) mxs_batt_boot(); }
+ /* + * TODO: Do not switch CPU clock to PLL if we are VDD5V is sourced + * from USB VBUS + */ mxs_power_clock2pll();
mxs_init_batt_bo(); @@ -819,6 +901,7 @@ static void mxs_power_configure_power_source(void)
#ifdef CONFIG_MX23 /* Fire up the VDDMEM LinReg now that we're all set. */ + debug("SPL: Enabling mx23 VDDMEM linear regulator\n"); writel(POWER_VDDMEMCTRL_ENABLE_LINREG | POWER_VDDMEMCTRL_ENABLE_ILIMIT, &power_regs->hw_power_vddmemctrl); #endif @@ -838,6 +921,8 @@ static void mxs_enable_output_rail_protection(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Enabling output rail protection\n"); + writel(POWER_CTRL_VDDD_BO_IRQ | POWER_CTRL_VDDA_BO_IRQ | POWER_CTRL_VDDIO_BO_IRQ, &power_regs->hw_power_ctrl_clr);
@@ -1077,6 +1162,8 @@ static void mxs_power_set_vddx(const struct mxs_vddx_cfg *cfg, */ static void mxs_setup_batt_detect(void) { + debug("SPL: Starting battery voltage measurement logic\n"); + mxs_lradc_init(); mxs_lradc_enable_batt_measurement(); early_delay(10); @@ -1111,6 +1198,8 @@ void mxs_power_init(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Initialising Power Block\n"); + mxs_ungate_power();
mxs_power_clock2xtal(); @@ -1123,9 +1212,13 @@ void mxs_power_init(void) mxs_power_configure_power_source(); mxs_enable_output_rail_protection();
+ debug("SPL: Setting VDDIO to 3V3 (brownout @ 3v15)\n"); mxs_power_set_vddx(&mxs_vddio_cfg, 3300, 3150); + + debug("SPL: Setting VDDD to 1V5 (brownout @ 1v0)\n"); mxs_power_set_vddx(&mxs_vddd_cfg, 1500, 1000); #ifdef CONFIG_MX23 + debug("SPL: Setting mx23 VDDMEM to 2V5 (brownout @ 1v7)\n"); mxs_power_set_vddx(&mxs_vddmem_cfg, 2500, 1700); #endif writel(POWER_CTRL_VDDD_BO_IRQ | POWER_CTRL_VDDA_BO_IRQ | @@ -1150,6 +1243,7 @@ void mxs_power_wait_pswitch(void) struct mxs_power_regs *power_regs = (struct mxs_power_regs *)MXS_POWER_BASE;
+ debug("SPL: Waiting for power switch input\n"); while (!(readl(&power_regs->hw_power_sts) & POWER_STS_PSWITCH_MASK)) ; }