From: Aneesh V <aneesh@ti.com>
To: Greg KH <greg@kroah.com>
Cc: linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org
Subject: Re: [PATCH 0/8] Add TI EMIF SDRAM controller driver
Date: Fri, 09 Mar 2012 09:29:36 +0530 [thread overview]
Message-ID: <4F598028.5020509@ti.com> (raw)
In-Reply-To: <20120308205944.GB16644@kroah.com>
On Friday 09 March 2012 02:29 AM, Greg KH wrote:
> On Thu, Mar 08, 2012 at 09:24:17PM +0530, Aneesh V wrote:
>> Add a driver for the EMIF SDRAM controller used in TI SoCs
>>
>> EMIF is an SDRAM controller that supports, based on its revision,
>> one or more of LPDDR2/DDR2/DDR3 protocols.This driver adds support
>> for LPDDR2.
>>
>> The driver supports the following features:
>> - Calculates the DDR AC timing parameters to be set in EMIF
>> registers using data from the device data-sheets and based
>> on the DDR frequency. If data from data-sheets is not available
>> default timing values from the JEDEC spec are used. These
>> will be safe, but not necessarily optimal
>> - API for changing timings during DVFS or at boot-up
>> - Temperature alert configuration and handling of temperature
>> alerts, if any for LPDDR2 devices
>> * temperature alert is based on periodic polling of MR4 mode
>> register in DDR devices automatically performed by hardware
>> * timings are de-rated and brought back to nominal when
>> temperature raises and falls respectively
>> - Cache of calculated register values to avoid re-calculating
>> them
>>
>> The driver will need some minor updates when it is eventually
>> integrated with Dynamic Voltage and Frequency Scaling (DVFS).
>> This can not be done now as DVFS support is not available in
>> the mainline yet.
>
> What will need to be updated in it? The userspace interface or
> something else?
The driver will need to register notifiers with regulator framework and
clock framework respectively for voltage and frequency notifications.
Also a hook will be needed for initiating the hardware sequence for
updating the AC timings. This process is under the control of Power
Reset and Clock Management(PRCM) module of OMAP.
>
> Why not wait until that code is accepted, it should be going into 3.4,
> right?
As Paul mentioned Core DVFS may take longer time. Besides, EMIF driver
is a pre-requisite for correct functioning of Core DVFS.
thanks,
Aneesh
next prev parent reply other threads:[~2012-03-09 3:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-08 15:54 [PATCH 0/8] Add TI EMIF SDRAM controller driver Aneesh V
2012-03-08 15:54 ` [PATCH 1/8] OMAP4: hwmod: add EMIF hw mod data Aneesh V
2012-03-08 16:41 ` Cousson, Benoit
2012-03-08 16:41 ` Cousson, Benoit
2012-03-08 16:43 ` Aneesh V
2012-03-08 15:54 ` [PATCH 2/8] misc: ddr: add LPDDR2 data from JESD209-2 Aneesh V
2012-03-08 15:54 ` [PATCH 3/8] misc: emif: add register definitions for EMIF Aneesh V
2012-03-08 15:54 ` [PATCH 4/8] misc: emif: add basic infrastructure for EMIF driver Aneesh V
2012-03-08 15:54 ` [PATCH 5/8] misc: emif: handle frequency and voltage change events Aneesh V
2012-03-08 15:54 ` [PATCH 6/8] misc: emif: add interrupt and temperature handling Aneesh V
2012-03-08 15:54 ` [PATCH 7/8] misc: emif: add one-time settings Aneesh V
2012-03-08 15:54 ` [PATCH 8/8] misc: emif: add debugfs entries for emif Aneesh V
2012-03-08 20:59 ` [PATCH 0/8] Add TI EMIF SDRAM controller driver Greg KH
2012-03-08 21:47 ` Paul Walmsley
2012-03-09 3:59 ` Aneesh V [this message]
2012-03-12 15:58 ` Santosh Shilimkar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F598028.5020509@ti.com \
--to=aneesh@ti.com \
--cc=greg@kroah.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-omap@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.