Messages in this thread |  | | Date | Mon, 04 Apr 2016 12:54:03 +0900 | | From | Jaehoon Chung <> | | Subject | Re: [PATCH v3 2/2] mmc: dw_mmc: add resets support to dw_mmc |
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On 04/02/2016 03:42 AM, Heiko Stuebner wrote: > Am Mittwoch, 30. März 2016, 20:40:31 schrieb Jaehoon Chung: >> modified Rob's mail address. >> >> On 03/30/2016 04:24 PM, Guodong Xu wrote: >>> mmc registers may in abnormal state if mmc is used in bootloader, >>> eg. to support booting from eMMC. So we need reset mmc registers >>> when kernel boots up, instead of assuming mmc is in clean state. >> >> Do you mean mmc(card side) register or dwmmc host controller's register on >> host side? >> >> According to dwmmc controller TMR, there are two reset signals. One is >> reset_n, other is rst_n. It seems this patch is relevant to reset_n(For >> host). (rst_n is hardware reset for card.) >> >> So could you clarify better? Then it's helpful to me for understanding.. > > I think that actually means a reset of controller IP block logic, outside > the control of the dw_mmc block itself. > > On Rockchip SoCs this gets triggered from the CRU (clock and reset unit), so > I guess if I'm reading the manual correctly, should be the reset_n signal of > the ip block. > > rst_n on the other hand gets triggered through a dw_mmc register setting and > is already handled by the dw_mmc driver.
Right, this patch is for reset_n signal. I didn't have seen the SoC that reset_n is designed. (Or i didn't realize...) If Rockchip is used from CRU (clock and reset unit), then i think that it makes sense.
Thanks for explanation.
Best Regards, Jaehoon Chung
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