Messages in this thread | | | From | Axel Lin <> | Date | Tue, 22 Feb 2011 18:38:40 +0800 | Subject | Re: [PATCH] ARM: pxa: support 806MHz operating points for PXA31x processors A2 stepping |
| |
2011/2/22 Igor Grinberg <grinberg@compulab.co.il>: > Hi, > > On 02/22/11 03:12, Axel Lin wrote: > >> Hi Igor, >> >>> Also, there is one thing that is not related to this patch, but >>> if you have the hardware, you need to be concerned with, >>> is that the vcc_core voltage has to be 1.4V, otherwise your >>> hardware will be unstable. >> I don't see any unstable issue on my device. >> But it seems the vcc_core and vcc_sram fields of pxa3xx_freq_info >> are not used now. > > Indeed, they are not used, because we don't have any DVFS driver for PXA3xx. > But, the hardware is running regardless of you have the driver or not ;) > There are other means to make sure the vcc_core voltage is set appropriately: > 1) could be already set (PMIC default) > 2) could be set by "Hardware-Controlled Voltage-Change Sequencer" automatically > (PXA3xx_DM_Vol_I chapter 6.8.3) if your PMIC is 100% compatible with PXA3xx > and PVCR[FVE/PVE] bits set accordingly. > 3) If your PMIC is for some reason not 100% compatible, then the voltage can be > set by regulator API or even by the bootloader. > > Anyway, to make sure it is set to the appropriate level, you need to measure it. > Usually, this line has some capacitors on it, so it shouldn't be a hard task > Thanks for the information. I'll check my settings.
> Now, regarding hardware instability: > I've seen instabilities related to the vcc_core set improperly, but it has never > showed up that quickly, sometimes it took a week of testing for it to show up. > But when it shows up, you can see strange things happening, like your DRAM > is messed or buses fail or the cpu just freezes. > > > Another thing (which could be related to the patch) is the package marking. > We have PXA3xx SoCs marked A2 stepping, but C624, which means that the > highest running frequency should not exceed 624MHz.
This means not all PXA310 A2 stepping supports 806Mhz. Can we differentiate the Cxxx option in software?
> What is your PXA3xx A2 marking in respect to Cxxx option?
Mine is 88AP310-A2-BGK2C806.
Regards, Axel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |