| Message ID | 1400637715-24117-1-git-send-email-peter.schumann@jeepxj.de |
|---|---|
| State | Superseded |
| Delegated to: | Stefano Babic |
| Headers | show |
On Wednesday, May 21, 2014 at 04:01:55 AM, Peter Schumann wrote: > This patch makes it possible to boot from battery on olinuxino Boards > from Olimex. > > We should not set DOUBLE_FETS in HW_POWER_MINPWR Please explain how you arrived to this conclusion. > , it makes my system > reset with in seconds while running on battery power. > > Also mxs_power_enable_4p2() should not be called if running from > battery. It switches VDDD and VDDA to LinReg mode and than turns off > the VDDIO DCDC supply. At this point the system resets. This has been tested on i.MX28 , can you please check what the differences are between these two chips and why it works only on one of them ? > If we run on battery this is no good idea because the LinRegs are > chained behind VDDIO and battery voltage seems not enough to power > the system from LinRegs. > Also is the power system already running on DCDC after BootROM hands > over to u-boot, so no sense in switching back to LinRegs. The BootROM never hands over to U-Boot, so this really makes no sense. Can you please explain ? The BootROM handles over to U-Boot SPL, which configures the power block. Also, I find it a very bad idea to depend on the BootROM to actually start the DCDC converter. I don't think we can universally say the DCDC converter is running when entering U-Boot SPL. I also don't think we can even depend on the power block configuration when exiting the BootROM -- for example in JTAG Boot Mode, the BootROM halts early in the boot process and will likely not configure anything with regards to the power block. [...] THanks! Best regards, Marek Vasut
Am 24.05.2014 12:44, schrieb Marek Vasut: > > Please explain how you arrived to this conclusion. > Hello Marek, I started writing an powerblock driver for the i.MX233 to use the imx233 olimex board with a battery. Short time (instant up to 90 seconds) after the 5v to battery handoff the system reseted. The system was running on DCDC prior to the handoff. I suspected that some of the power rails where droping and trigger hardware brownouts. But this was not the case. The DCDC got shutdown and some ms after that the rails begun to drop. I have some scope pic of this happening i it is of interest. I than tried out some random bits in the MINPWR register and the reset problem was gone. Than I track down it to this 1 bit causing the instability. > > This has been tested on i.MX28 , can you please check what the differences are > between these two chips and why it works only on one of them ? > From the block diagram in the AN4199 pdf i am quite sure that it wont work this way on the i.MX28 either. The VDDIO Linreg is sourced from the 5V rail. So if we run from battery only we can not deactivate VDDIO from DCDC by setting DISABLE_FET. > The BootROM never hands over to U-Boot, so this really makes no sense. Can you > please explain ? The BootROM handles over to U-Boot SPL, which configures the > power block. > Sorry I meant the U-Boot SPL.I not that familiar with U-Boot architecture. > Also, I find it a very bad idea to depend on the BootROM to actually start the > DCDC converter. I don't think we can universally say the DCDC converter is > running when entering U-Boot SPL. I also don't think we can even depend on the > power block configuration when exiting the BootROM -- for example in JTAG Boot > Mode, the BootROM halts early in the boot process and will likely not configure > anything with regards to the power block. I am with you at the point that proper initialization is very important and we should not rely on BootROM. If the system is running on battery only, we should not switch the VDDIO regulator to Linreg mode because there are no 5V to source it. In mxs_power_enable_4p2() all Regulators get switched to Linreg mode and that kills the power to hole system and there by is triggering an brownout reset. The mxs_power_enable_4p2() function can only work if we assume there is 5V present. I hope I got clearer way this will not work in a battery only scenario. Best regards, Peter Schumann
On Wednesday, May 21, 2014 at 04:01:55 AM, Peter Schumann wrote: > This patch makes it possible to boot from battery on olinuxino Boards > from Olimex. > > We should not set DOUBLE_FETS in HW_POWER_MINPWR, it makes my system > reset with in seconds while running on battery power. > > Also mxs_power_enable_4p2() should not be called if running from > battery. It switches VDDD and VDDA to LinReg mode and than turns off > the VDDIO DCDC supply. At this point the system resets. > If we run on battery this is no good idea because the LinRegs are > chained behind VDDIO and battery voltage seems not enough to power > the system from LinRegs. > Also is the power system already running on DCDC after BootROM hands > over to u-boot, so no sense in switching back to LinRegs. Sorry for the late reply, I'm somewhat congested recently. In the meantime, I was not able to test this yet. But you're missing Signed-off-by: line, can you please re-send this with a proper SoB line [1] ? [1] http://www.denx.de/wiki/U-Boot/Patches#General_Patch_Submission_Rules Thanks Best regards, Marek Vasut
On Friday, June 06, 2014 at 12:18:09 AM, Marek Vasut wrote: > On Wednesday, May 21, 2014 at 04:01:55 AM, Peter Schumann wrote: > > This patch makes it possible to boot from battery on olinuxino Boards > > from Olimex. > > > > We should not set DOUBLE_FETS in HW_POWER_MINPWR, it makes my system > > reset with in seconds while running on battery power. > > > > Also mxs_power_enable_4p2() should not be called if running from > > battery. It switches VDDD and VDDA to LinReg mode and than turns off > > the VDDIO DCDC supply. At this point the system resets. > > If we run on battery this is no good idea because the LinRegs are > > chained behind VDDIO and battery voltage seems not enough to power > > the system from LinRegs. > > Also is the power system already running on DCDC after BootROM hands > > over to u-boot, so no sense in switching back to LinRegs. > > Sorry for the late reply, I'm somewhat congested recently. In the meantime, > I was not able to test this yet. But you're missing Signed-off-by: line, > can you please re-send this with a proper SoB line [1] ? > > [1] http://www.denx.de/wiki/U-Boot/Patches#General_Patch_Submission_Rules Bump? Best regards, Marek Vasut
> > Bump? > > Best regards, > Marek Vasut > Hi Marek, I am occupied with work at the moment. I will get it done at the weekend. Best regards, Peter Schumann
On Friday, June 13, 2014 at 09:36:51 AM, Peter Schumann wrote: > > Bump? > > > > Best regards, > > Marek Vasut > > Hi Marek, > > I am occupied with work at the moment. I will get it done at the weekend. Thanks! Best regards, Marek Vasut
diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c index d25019a..0cbb6c4 100644 --- a/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c +++ b/arch/arm/cpu/arm926ejs/mxs/spl_power_init.c @@ -237,9 +237,6 @@ static void mxs_src_power_init(void) POWER_LOOPCTRL_RCSCALE_THRESH | POWER_LOOPCTRL_EN_RCSCALE_8X); - clrsetbits_le32(&power_regs->hw_power_minpwr, - POWER_MINPWR_HALFFETS, POWER_MINPWR_DOUBLE_FETS); - /* 5V to battery handoff ... FIXME */ setbits_le32(&power_regs->hw_power_5vctrl, POWER_5VCTRL_DCDC_XFER); early_delay(30); @@ -631,8 +628,6 @@ static void mxs_batt_boot(void) writel(POWER_CTRL_ENIRQ_DCDC4P2_BO, &power_regs->hw_power_ctrl_clr); - clrsetbits_le32(&power_regs->hw_power_minpwr, - POWER_MINPWR_HALFFETS, POWER_MINPWR_DOUBLE_FETS); mxs_power_set_linreg(); @@ -655,7 +650,6 @@ static void mxs_batt_boot(void) POWER_5VCTRL_CHARGE_4P2_ILIMIT_MASK, 0x8 << POWER_5VCTRL_CHARGE_4P2_ILIMIT_OFFSET); - mxs_power_enable_4p2(); } /**