On 19 July 2016 at 02:08, Ziyuan Xu <xzy...@rock-chips.com> wrote: > Hi Jaehoon, > > > On 2016年07月19日 15:51, Jaehoon Chung wrote: >> >> Hi, >> >> On 07/19/2016 04:40 PM, Ziyuan Xu wrote: >>> >>> Hi Jaehoon, >>> >>> On 2016年07月19日 12:22, Jaehoon Chung wrote: >>>> >>>> Hi Ziyuan, >>>> >>>> On 07/19/2016 11:33 AM, Ziyuan Xu wrote: >>>>> >>>>> Hi Jaehoon, >>>>> >>>>> On 2016年07月19日 10:03, Jaehoon Chung wrote: >>>>>> >>>>>> Hi Ziyuan, >>>>>> >>>>>> On 07/19/2016 10:38 AM, Ziyuan Xu wrote: >>>>>>> >>>>>>> It's no need to speed 10 seconds to wait the mmc device out from busy >>>>>>> status. 500 milliseconds enough. >>>>>> >>>>>> I agreed that 10 seconds is too big.. >>>>>> Could you explain more how you get 500ms and feel enough? >>>>> >>>>> Ordinarily, there are 3 types of scenarios that the mmc device was >>>>> busy: >>>>> 1. The mmc interface didn't initialize (eg. gpio iomux) >>>>> The device will be busy status until gpio iomux. >>>>> >>>>> 2. The last command with data transfer. >>>>> The maximum value of data timeout is 0xffffff cyles(see dwi databook >>>>> Timeout Register), and the clock is up to 52MHZ under high speed mode. >>>>> timeout = 0xffffff * 1/52M = 0.32s >>>>> >>>>> 3. voltage switch >>>>> U-BOOT doesn't support voltage switch. >>>>> >>>>> In summary, I think 500 milliseconds is enough. What do you think? >>>> >>>> I think it's not important thing. >>>> >>>> This is for checking whether card is busy or not before sending command. >>>> I think it's not relevant to Timeout register. Just ensure that card is >>>> not busy before sending command. >>>> And there is no effect for I/O performance, isn't? >>> >>> Yup, I agree with you. For scenarios 2, I mean that if the last command >>> with data transfer, we will hit data_busy assertion probably. If the mmc >>> device remains in a busy state more than 500ms, I think it may also be busy >>> state after 10s. >>>> >>>> But 50ms is not bad. :) It's personal preference. >>> >>> BTW, the timeout value is 500ms in kernel. >> >> Yep, it looks good to me. :) >> I have tested your patch with Exynos SoCs. >> >> Reviewed-by: Jaehoon Chung <jh80.ch...@samsung.com> >> Tested-by: Jaehoon Chung <jh80.ch...@samsung.com> > > Thanks for your test and review! >
Let's get others to test this. Applied to u-boot-dm, thanks! _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
