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From: Chris Ball <cjb@laptop.org>
To: "Dong, Chuanxiao" <chuanxiao.dong@intel.com>
Cc: "S, Venkatraman" <svenkatr@ti.com>,
	Jaehoon Chung <jh80.chung@samsung.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	Hanumath Prasad <hanumath.prasad@stericsson.com>,
	"per.forlin@stericsson.com" <per.forlin@stericsson.com>,
	Sebastian Rasmussen <sebras@gmail.com>,
	Konstantin Dorfman <kdorfman@codeaurora.org>
Subject: Re: [PATCH v5] mmc: support BKOPS feature for eMMC
Date: Sat, 07 Jan 2012 21:21:29 -0500	[thread overview]
Message-ID: <m2pqevvsra.fsf@bob.laptop.org> (raw)
In-Reply-To: <17296D9F8FF2234F831FC3DF505A87A90FCB43D7@SHSMSX101.ccr.corp.intel.com> (Chuanxiao Dong's message of "Sun, 8 Jan 2012 02:18:44 +0000")

Hi,

On Sat, Jan 07 2012, Dong, Chuanxiao wrote:
>> In my understanding, the EXT_CSD_BKOPS_EN should be _updated_by_ the
>> host controller to 1 at initialization time, to indicate to the
>> device, as per the spec.
>> Otherwise, the device would decide that the host doesn't support
>> software controlled BKOPS.
>
> EXT_CSD_BKOPS_EN is a onetime programmable register, which is not
> suitable for driver to touch I think. This can be updated by host
> controller, but should not happened in driver. This register can be
> configured by some platform firmware or some eMMC FW from vendor. For
> what driver needs to do, is just to read this onetime programmable and
> to know whether BKOPS is enabled. It is like hardware reset
> feature. RST_n_FUNCTION is only a onetime programmable register which
> can indicate whether hardware reset feature is enabled. Driver just
> needs to read it out and to know whether hardware reset feature can be
> used. So I agree with Jaehoon Chung's implementation.

I agree -- we don't touch fuses in the driver.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

  reply	other threads:[~2012-01-08  2:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-05  0:55 [PATCH v5] mmc: support BKOPS feature for eMMC Jaehoon Chung
2012-01-06 16:42 ` S, Venkatraman
2012-01-08  2:18   ` Dong, Chuanxiao
2012-01-08  2:21     ` Chris Ball [this message]
     [not found] ` <4F0ACF14.1090904@stericsson.com>
2012-01-10  0:31   ` Jaehoon Chung
2012-01-11 13:31 ` S, Venkatraman
2012-01-11 19:32   ` Chris Ball
2012-01-12  2:10     ` Jaehoon Chung

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