Re: [PATCH 3/3] ARM: dts: EMIF and LPDDR2 device tree data for OMAP5 boards

Re: [PATCH 3/3] ARM: dts: EMIF and LPDDR2 device tree data for OMAP5 boards

[Lokesh Vutla]

+ devicetree-discuss

Hi Benoit,

On Wednesday 10 October 2012 08:31 PM, Benoit Cousson wrote:
> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>> Device tree data for the EMIF sdram controllers in OMAP5
>> and LPDDR2 memory devices attached to OMAP5 boards.
>
> Nit: Could you make a sentence with a verb to explain what you are doing
> in this patch.
I am really sorry about this.
I ll make sure that all patch descriptions will be clear in V2 of this 
patch series.

In this patch I am adding device tree data for LPDDR2 memory devices 
attached to omap5-sevm and also adding device tree data for EMIF sdram 
controllers in OMAP5.
>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>>   arch/arm/boot/dts/lpddr2_data.dtsi |   64 +++++++++++++++++++++++++++++++++++-
>>   arch/arm/boot/dts/omap5-evm.dts    |   11 +++++++
>>   arch/arm/boot/dts/omap5.dtsi       |   18 ++++++++++
>>   3 files changed, 92 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/boot/dts/lpddr2_data.dtsi b/arch/arm/boot/dts/lpddr2_data.dtsi
>> index f97f70f..8e8c1bc 100644
>> --- a/arch/arm/boot/dts/lpddr2_data.dtsi
>> +++ b/arch/arm/boot/dts/lpddr2_data.dtsi
>> @@ -3,7 +3,7 @@
>>    */
>>
>>   / {
>> -	elpida_ECB240ABACN: lpddr2 {
>> +	elpida_ECB240ABACN: lpddr2@0 {
>>   		compatible	= "Elpida,ECB240ABACN","jedec,lpddr2-s4";
>>   		density		= <2048>;
>>   		io-width	= <32>;
>> @@ -64,4 +64,66 @@
>>   			tDQSCK-max-derated = <6000>;
>>   		};
>>   	};
>> +
>> +	samsung_K3PE0E000B: lpddr2@1 {
>
> I'm confused now, why are you reusing the same lpddr2_data.dtsi file?
> You should create a file per memory. That will make the reuse much easier.
>
> If the goal of your first patch was to do that, it is then the wrong
> approach.
Yes, I wanted to group data for all lppdr2 devices in a single file than 
creating separate file for each device.
May be a dumb question, Why can't we group data for all the lpddr2 
devices in a single file?
>
>> +		compatible	= "Samsung,K3PE0E000B","jedec,lpddr2-s4";
>> +		density		= <4096>;
>> +		io-width	= <32>;
>> +
>> +		tRPab-min-tck	= <3>;
>> +		tRCD-min-tck	= <3>;
>> +		tWR-min-tck	= <3>;
>> +		tRASmin-min-tck	= <3>;
>> +		tRRD-min-tck	= <2>;
>> +		tWTR-min-tck	= <2>;
>> +		tXP-min-tck	= <2>;
>> +		tRTP-min-tck	= <2>;
>> +		tCKE-min-tck	= <3>;
>> +		tCKESR-min-tck	= <3>;
>> +		tFAW-min-tck	= <8>;
>> +
>> +		timings_samsung_K3PE0E000B_533mhz: lpddr2-timings@0 {
>> +			compatible	= "jedec,lpddr2-timings";
>> +			min-freq	= <10000000>;
>> +			max-freq	= <533333333>;
>> +			tRPab		= <21000>;
>> +			tRCD		= <18000>;
>> +			tWR		= <15000>;
>> +			tRAS-min	= <42000>;
>> +			tRRD		= <10000>;
>> +			tWTR		= <7500>;
>> +			tXP		= <7500>;
>> +			tRTP		= <7500>;
>> +			tCKESR		= <15000>;
>> +			tDQSCK-max	= <5500>;
>> +			tFAW		= <50000>;
>> +			tZQCS		= <90000>;
>> +			tZQCL		= <360000>;
>> +			tZQinit		= <1000000>;
>> +			tRAS-max-ns	= <70000>;
>> +			tDQSCK-max-derated = <5620>;
>> +		};
>> +
>> +		timings_samsung_K3PE0E000B_266mhz: lpddr2-timings@1 {
>> +			compatible	= "jedec,lpddr2-timings";
>> +			min-freq	= <10000000>;
>> +			max-freq	= <266666666>;
>> +			tRPab		= <21000>;
>> +			tRCD		= <18000>;
>> +			tWR		= <15000>;
>> +			tRAS-min	= <42000>;
>> +			tRRD		= <10000>;
>> +			tWTR		= <7500>;
>> +			tXP		= <7500>;
>> +			tRTP		= <7500>;
>> +			tCKESR		= <15000>;
>> +			tDQSCK-max	= <5500>;
>> +			tFAW		= <50000>;
>> +			tZQCS		= <90000>;
>> +			tZQCL		= <360000>;
>> +			tZQinit		= <1000000>;
>> +			tRAS-max-ns	= <70000>;
>> +			tDQSCK-max-derated = <6000>;
>> +		};
>> +	};
>>   };
>> diff --git a/arch/arm/boot/dts/omap5-evm.dts b/arch/arm/boot/dts/omap5-evm.dts
>> index 6f87e1a..8a952f8 100644
>> --- a/arch/arm/boot/dts/omap5-evm.dts
>> +++ b/arch/arm/boot/dts/omap5-evm.dts
>> @@ -8,6 +8,7 @@
>>   /dts-v1/;
>>
>>   /include/ "omap5.dtsi"
>> +/include/ "lpddr2_data.dtsi"
>>
>>   / {
>>   	model = "TI OMAP5 EVM board";
>> @@ -82,3 +83,13 @@
>>   			0x020700d9>;	/* SEARCH */
>>   	linux,input-no-autorepeat;
>>   };
>> +
>> +&emif1 {
>> +	cs1-used;
>> +	device-handle = <&samsung_K3PE0E000B>;
>> +};
>> +
>> +&emif2 {
>> +	cs1-used;
>> +	device-handle = <&samsung_K3PE0E000B>;
>> +};
>> diff --git a/arch/arm/boot/dts/omap5.dtsi b/arch/arm/boot/dts/omap5.dtsi
>> index 5db33f4..40b41c2 100644
>> --- a/arch/arm/boot/dts/omap5.dtsi
>> +++ b/arch/arm/boot/dts/omap5.dtsi
>> @@ -319,5 +319,23 @@
>>   			ti,buffer-size = <128>;
>>   			ti,hwmods = "mcbsp3";
>>   		};
>> +
>> +		emif1: emif@0x4c000000 {
>> +			compatible	= "ti,emif-4d5";
>> +			ti,hwmods	= "emif1";
>> +			phy-type	= <2>;
>> +			hw-caps-read-idle-ctrl;
>> +			hw-caps-ll-interface;
>> +			hw-caps-temp-alert;
>
> You should now add the reg, and interrupt attributes as well.
OK I ll add these fields.

Thanks,
Lokesh
>
> Regards,
> Benoit
>

Re: [PATCH 1/3] ARM: dts: Renaming elpida_ecb240abacn.dtsi as lpddr2_data.dtsi

[Lokesh Vutla]

+ devicetree-discuss

Hi Benoit,

On Wednesday 10 October 2012 08:18 PM, Benoit Cousson wrote:
> Hi Lokesh,
>
> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>> Renaming elpida_ecb240abacn.dtsi file generic, so that the
>> same file can be reused for other parts from different vendors.
>
> Could you elaborate a little bit?
> Are these settings purely reflecting lpddr2 spec timings?

The basic idea is to group data for all the lpddr2 devices in a single 
file instead of creating separate file for each lpddr2 device.

Right now the file elpida_ecb240abacn.dtsi contains only data for 
lpddr2-s4 2G parts from Elpida.
I wanted to add data for lpddr2-s4 4G parts from Samsung.
So I renamed the file elpida_ecb240abacn.dtsi as lpddr2_data.dtsi.

Please let me know if more clarification is needed.

Thanks,
Lokesh
>
> Regards,
> Benoit
>
>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>>   arch/arm/boot/dts/{elpida_ecb240abacn.dtsi => lpddr2_data.dtsi} |    0
>>   arch/arm/boot/dts/omap4-panda.dts                               |    2 +-
>>   arch/arm/boot/dts/omap4-sdp.dts                                 |    2 +-
>>   3 files changed, 2 insertions(+), 2 deletions(-)
>>   rename arch/arm/boot/dts/{elpida_ecb240abacn.dtsi => lpddr2_data.dtsi} (100%)
>>
>> diff --git a/arch/arm/boot/dts/elpida_ecb240abacn.dtsi b/arch/arm/boot/dts/lpddr2_data.dtsi
>> similarity index 100%
>> rename from arch/arm/boot/dts/elpida_ecb240abacn.dtsi
>> rename to arch/arm/boot/dts/lpddr2_data.dtsi
>> diff --git a/arch/arm/boot/dts/omap4-panda.dts b/arch/arm/boot/dts/omap4-panda.dts
>> index 20b966e..09d3a32 100644
>> --- a/arch/arm/boot/dts/omap4-panda.dts
>> +++ b/arch/arm/boot/dts/omap4-panda.dts
>> @@ -8,7 +8,7 @@
>>   /dts-v1/;
>>
>>   /include/ "omap4.dtsi"
>> -/include/ "elpida_ecb240abacn.dtsi"
>> +/include/ "lpddr2_data.dtsi"
>>
>>   / {
>>   	model = "TI OMAP4 PandaBoard";
>> diff --git a/arch/arm/boot/dts/omap4-sdp.dts b/arch/arm/boot/dts/omap4-sdp.dts
>> index 94a23b3..dd749fc 100644
>> --- a/arch/arm/boot/dts/omap4-sdp.dts
>> +++ b/arch/arm/boot/dts/omap4-sdp.dts
>> @@ -8,7 +8,7 @@
>>   /dts-v1/;
>>
>>   /include/ "omap4.dtsi"
>> -/include/ "elpida_ecb240abacn.dtsi"
>> +/include/ "lpddr2_data.dtsi"
>>
>>   / {
>>   	model = "TI OMAP4 SDP board";
>>
>

Re: [PATCH 3/3] ARM: dts: EMIF and LPDDR2 device tree data for OMAP5 boards

[Benoit Cousson]

Hi Lokesh,

On 10/11/2012 08:16 AM, Lokesh Vutla wrote:
> + devicetree-discuss
> 
> Hi Benoit,
> 
> On Wednesday 10 October 2012 08:31 PM, Benoit Cousson wrote:
>> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>>> Device tree data for the EMIF sdram controllers in OMAP5
>>> and LPDDR2 memory devices attached to OMAP5 boards.
>>
>> Nit: Could you make a sentence with a verb to explain what you are doing
>> in this patch.
> I am really sorry about this.
> I ll make sure that all patch descriptions will be clear in V2 of this
> patch series.
> 
> In this patch I am adding device tree data for LPDDR2 memory devices
> attached to omap5-sevm and also adding device tree data for EMIF sdram
> controllers in OMAP5.
>>
>>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>>> ---
>>>   arch/arm/boot/dts/lpddr2_data.dtsi |   64
>>> +++++++++++++++++++++++++++++++++++-
>>>   arch/arm/boot/dts/omap5-evm.dts    |   11 +++++++
>>>   arch/arm/boot/dts/omap5.dtsi       |   18 ++++++++++
>>>   3 files changed, 92 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm/boot/dts/lpddr2_data.dtsi
>>> b/arch/arm/boot/dts/lpddr2_data.dtsi
>>> index f97f70f..8e8c1bc 100644
>>> --- a/arch/arm/boot/dts/lpddr2_data.dtsi
>>> +++ b/arch/arm/boot/dts/lpddr2_data.dtsi
>>> @@ -3,7 +3,7 @@
>>>    */
>>>
>>>   / {
>>> -    elpida_ECB240ABACN: lpddr2 {
>>> +    elpida_ECB240ABACN: lpddr2@0 {
>>>           compatible    = "Elpida,ECB240ABACN","jedec,lpddr2-s4";
>>>           density        = <2048>;
>>>           io-width    = <32>;
>>> @@ -64,4 +64,66 @@
>>>               tDQSCK-max-derated = <6000>;
>>>           };
>>>       };
>>> +
>>> +    samsung_K3PE0E000B: lpddr2@1 {
>>
>> I'm confused now, why are you reusing the same lpddr2_data.dtsi file?
>> You should create a file per memory. That will make the reuse much
>> easier.
>>
>> If the goal of your first patch was to do that, it is then the wrong
>> approach.
> Yes, I wanted to group data for all lppdr2 devices in a single file than
> creating separate file for each device.
> May be a dumb question, Why can't we group data for all the lpddr2
> devices in a single file?

Well, why should we do that? What will be the advantage?

That will increase the size of the DTS/DTB with data nobody will care if
only one type of memory is used on a given platform.

Going in the same direction you can consider adding every OMAP
description into a single DTS... Does that really make sense?

So clearly there is no point doing that, it will cluttered the OMAP4 DTB
with useless Samsung memory data. And the same issue for OMAP5 board
that will contain Elpida memory information. And it will get worst each
time someone will want to add a new memory in this file.

You should just include the data you need for a given board.


Regards,
Benoit

Re: [PATCH 3/3] ARM: dts: EMIF and LPDDR2 device tree data for OMAP5 boards

[Santosh Shilimkar]

On Thursday 11 October 2012 01:41 PM, Benoit Cousson wrote:
> Hi Lokesh,
>
> On 10/11/2012 08:16 AM, Lokesh Vutla wrote:
>> + devicetree-discuss
>>
>> Hi Benoit,
>>
>> On Wednesday 10 October 2012 08:31 PM, Benoit Cousson wrote:
>>> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>>>> Device tree data for the EMIF sdram controllers in OMAP5
>>>> and LPDDR2 memory devices attached to OMAP5 boards.
>>>
>>> Nit: Could you make a sentence with a verb to explain what you are doing
>>> in this patch.
>> I am really sorry about this.
>> I ll make sure that all patch descriptions will be clear in V2 of this
>> patch series.
>>
>> In this patch I am adding device tree data for LPDDR2 memory devices
>> attached to omap5-sevm and also adding device tree data for EMIF sdram
>> controllers in OMAP5.
>>>
>>>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>>>> ---
>>>>    arch/arm/boot/dts/lpddr2_data.dtsi |   64
>>>> +++++++++++++++++++++++++++++++++++-
>>>>    arch/arm/boot/dts/omap5-evm.dts    |   11 +++++++
>>>>    arch/arm/boot/dts/omap5.dtsi       |   18 ++++++++++
>>>>    3 files changed, 92 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/arch/arm/boot/dts/lpddr2_data.dtsi
>>>> b/arch/arm/boot/dts/lpddr2_data.dtsi
>>>> index f97f70f..8e8c1bc 100644
>>>> --- a/arch/arm/boot/dts/lpddr2_data.dtsi
>>>> +++ b/arch/arm/boot/dts/lpddr2_data.dtsi
>>>> @@ -3,7 +3,7 @@
>>>>     */
>>>>
>>>>    / {
>>>> -    elpida_ECB240ABACN: lpddr2 {
>>>> +    elpida_ECB240ABACN: lpddr2@0 {
>>>>            compatible    = "Elpida,ECB240ABACN","jedec,lpddr2-s4";
>>>>            density        = <2048>;
>>>>            io-width    = <32>;
>>>> @@ -64,4 +64,66 @@
>>>>                tDQSCK-max-derated = <6000>;
>>>>            };
>>>>        };
>>>> +
>>>> +    samsung_K3PE0E000B: lpddr2@1 {
>>>
>>> I'm confused now, why are you reusing the same lpddr2_data.dtsi file?
>>> You should create a file per memory. That will make the reuse much
>>> easier.
>>>
>>> If the goal of your first patch was to do that, it is then the wrong
>>> approach.
>> Yes, I wanted to group data for all lppdr2 devices in a single file than
>> creating separate file for each device.
>> May be a dumb question, Why can't we group data for all the lpddr2
>> devices in a single file?
>
> Well, why should we do that? What will be the advantage?
>
> That will increase the size of the DTS/DTB with data nobody will care if
> only one type of memory is used on a given platform.
>
> Going in the same direction you can consider adding every OMAP
> description into a single DTS... Does that really make sense?
>
> So clearly there is no point doing that, it will cluttered the OMAP4 DTB
> with useless Samsung memory data. And the same issue for OMAP5 board
> that will contain Elpida memory information. And it will get worst each
> time someone will want to add a new memory in this file.
>
> You should just include the data you need for a given board.
>
I agree with Benoit. Keeping the memory data files separate will be
better and also if some non-omap boards is using the memory parts,
the separate files can be re-used.

Regards
Santosh

Re: [PATCH 1/3] ARM: dts: Renaming elpida_ecb240abacn.dtsi as lpddr2_data.dtsi

[Benoit Cousson]

On 10/11/2012 08:16 AM, Lokesh Vutla wrote:
> + devicetree-discuss
> 
> Hi Benoit,
> 
> On Wednesday 10 October 2012 08:18 PM, Benoit Cousson wrote:
>> Hi Lokesh,
>>
>> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>>> Renaming elpida_ecb240abacn.dtsi file generic, so that the
>>> same file can be reused for other parts from different vendors.
>>
>> Could you elaborate a little bit?
>> Are these settings purely reflecting lpddr2 spec timings?
> 
> The basic idea is to group data for all the lpddr2 devices in a single
> file instead of creating separate file for each lpddr2 device.
> 
> Right now the file elpida_ecb240abacn.dtsi contains only data for
> lpddr2-s4 2G parts from Elpida.
> I wanted to add data for lpddr2-s4 4G parts from Samsung.
> So I renamed the file elpida_ecb240abacn.dtsi as lpddr2_data.dtsi.
> 
> Please let me know if more clarification is needed.

Well, not anymore... as explained in the previous email, you should not
do that.
Keep the Elpida file and create another one for the Samsung part.
Then each board will be able to select the proper one and include only
the relevant data.

Regards,
Benoit

Re: [PATCH 1/3] ARM: dts: Renaming elpida_ecb240abacn.dtsi as lpddr2_data.dtsi

[Lokesh Vutla]

On Thursday 11 October 2012 01:58 PM, Benoit Cousson wrote:
> On 10/11/2012 08:16 AM, Lokesh Vutla wrote:
>> + devicetree-discuss
>>
>> Hi Benoit,
>>
>> On Wednesday 10 October 2012 08:18 PM, Benoit Cousson wrote:
>>> Hi Lokesh,
>>>
>>> On 10/10/2012 02:05 PM, Lokesh Vutla wrote:
>>>> Renaming elpida_ecb240abacn.dtsi file generic, so that the
>>>> same file can be reused for other parts from different vendors.
>>>
>>> Could you elaborate a little bit?
>>> Are these settings purely reflecting lpddr2 spec timings?
>>
>> The basic idea is to group data for all the lpddr2 devices in a single
>> file instead of creating separate file for each lpddr2 device.
>>
>> Right now the file elpida_ecb240abacn.dtsi contains only data for
>> lpddr2-s4 2G parts from Elpida.
>> I wanted to add data for lpddr2-s4 4G parts from Samsung.
>> So I renamed the file elpida_ecb240abacn.dtsi as lpddr2_data.dtsi.
>>
>> Please let me know if more clarification is needed.
>
> Well, not anymore... as explained in the previous email, you should not
> do that.
> Keep the Elpida file and create another one for the Samsung part.
> Then each board will be able to select the proper one and include only
> the relevant data.
OK, Ill agree with you.
I ll do the changes and post the V2.

Thanks,
Lokesh
>
> Regards,
> Benoit
>