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From: Heiko Stuebner <heiko@sntech.de>
To: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Guodong Xu <guodong.xu@linaro.org>,
	shawn.lin@rock-chips.com,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	pawel.moll@arm.com, mark.rutland@arm.com,
	ijc+devicetree@hellion.org.uk, galak@codeaurora.org,
	ulf.hansson@linaro.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Xinwei Kong <kong.kongxinwei@hisilicon.com>,
	Zhangfei Gao <zhangfei.gao@linaro.org>,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH v3 2/2] mmc: dw_mmc: add resets support to dw_mmc
Date: Fri, 01 Apr 2016 20:42 +0200	[thread overview]
Message-ID: <1754831.FONmYVUinF@phil> (raw)
In-Reply-To: <56FBBB2F.5030308@samsung.com>

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.


Heiko

  reply	other threads:[~2016-04-01 18:42 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-30  7:24 [PATCH v3 0/2] mmc: dw_mmc: controller reset support Guodong Xu
2016-03-30  7:24 ` [PATCH v3 1/2] Documentation: synopsys-dw-mshc: add binding for resets Guodong Xu
2016-03-30  7:24 ` [PATCH v3 2/2] mmc: dw_mmc: add resets support to dw_mmc Guodong Xu
2016-03-30 11:40   ` Jaehoon Chung
2016-04-01 18:42     ` Heiko Stuebner [this message]
2016-04-02 12:11       ` Guodong Xu
2016-04-04  3:54       ` Jaehoon Chung
2016-04-01 18:42   ` Heiko Stuebner
2016-04-02 13:39     ` Guodong Xu
2016-04-02 14:03       ` Heiko Stuebner
2016-05-25 13:33         ` Guodong Xu
     [not found] ` <1459322696-29919-1-git-send-email-guodong.xu-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-03-30 11:45   ` [PATCH v3 0/2] mmc: dw_mmc: controller reset support Shawn Lin

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