[PATCH v5 0/7] Add TI EMIF SDRAM controller driver

Santosh Shilimkar santosh.shilimkar at ti.com
Wed May 2 02:50:24 EDT 2012


Greg,

On Wednesday 02 May 2012 10:46 AM, Greg KH wrote:
> On Fri, Apr 27, 2012 at 05:54:02PM +0530, Santosh Shilimkar wrote:
>> Add a driver for the EMIF SDRAM controller used in Texas Instrument 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.
>>
>> Discussions with Santosh Shilimkar <santosh.shilimkar at ti.com>
>> were immensely helpful in shaping up the interfaces. Vibhore Vardhan
>> <vvardhan at gmail.com> did the initial code snippet for thermal
>> handling.
>>
>> Testing: 
>> - The driver is tested on OMAP4430 SDP.
>> - The driver in a slightly adapted form is also tested on OMAP5.
>> - Since mainline kernel doesn't have DVFS support yet,
>>   testing was done using a test module.
>> - Temperature alert handling was tested with simulated interrupts
>>   and faked temperature values as testing all cases in real-life
>>   scenarios is difficult.
>> - Tested the driver as a module
>>
>> Cc: Greg KH <greg at kroah.com>
> 
> This all looks good to me now, thanks for reworking this.
> 
> So, do you want me to take this through my "driver" tree to get to Linus
> for 3.5, or do you want it to go through somewhere else?
> 
> If somewhere else, that's fine with me, consider this an:
> 	Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> 
> If you want me to take it, just let me know, whichever you prefer is
> fine with me.
> 
Can you take this one through your 3.5 driver tree please ?
Thanks for help.

Regards
Santosh





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