Overclock RAM Speed

Post Reply
sgudla
Posts: 3
Joined: Fri Jan 03, 2020 9:17 am
languages_spoken: english
Has thanked: 4 times
Been thanked: 0
Contact:

Overclock RAM Speed

Unread post by sgudla » Fri Jan 03, 2020 9:22 am

Hi All,

I am trying to figure out a way to modify the RAM timing parameters like (tCL, tRAS, etc.). In desktops we can do this via BIOS. Is there any way to do this in android devices? Any leads will be of great help.

Thanks.

User avatar
odroid
Site Admin
Posts: 33043
Joined: Fri Feb 22, 2013 11:14 pm
languages_spoken: English
ODROIDs: ODROID
Has thanked: 296 times
Been thanked: 417 times
Contact:

Re: Overclock RAM Speed

Unread post by odroid » Fri Jan 03, 2020 9:43 am

The DRAM clock parameters exist in the Kernel DMC drivers and there is no simple way to change it like PC BIOS.
If you have enough Kernel development experience, you can search the DMC drivers in our Android source code.

Anyway, there is not much room to improve the DRAM throughput performance since LPDDR3 configuration has been already optimized.
These users thanked the author odroid for the post:
sgudla (Sat Jan 04, 2020 6:58 am)

joy
Posts: 993
Joined: Fri Oct 02, 2015 1:44 pm
languages_spoken: english
ODROIDs: ODROID-C1+, XU4, X
Has thanked: 39 times
Been thanked: 94 times
Contact:

Re: Overclock RAM Speed

Unread post by joy » Fri Jan 03, 2020 9:44 am

If you're planning to use android of XU4, you can refer to devfreq mif drivers (= exynos5422 DMC driver) in kernel 3.10.y.
https://github.com/hardkernel/linux/blo ... mif.c#L208
But, unfortunately we don't have any available material that describes internal registers to control tCL, RAS or CAS. :(

For kernel 4.14.y, there is no mif driver so far.
So we made an interface to control ram clocking on u-boot stage.
viewtopic.php?f=93&t=27117
https://wiki.odroid.com/odroid-xu4/appl ... _overclock

For kernel 5.x, I need to check it.
Last edited by joy on Fri Jan 03, 2020 5:19 pm, edited 1 time in total.
These users thanked the author joy for the post:
sgudla (Sat Jan 04, 2020 6:58 am)

joy
Posts: 993
Joined: Fri Oct 02, 2015 1:44 pm
languages_spoken: english
ODROIDs: ODROID-C1+, XU4, X
Has thanked: 39 times
Been thanked: 94 times
Contact:

Re: Overclock RAM Speed

Unread post by joy » Fri Jan 03, 2020 9:49 am

@sgudla,
As odroid mentioned, we've already looked into the rooms and put some kinds of tests.
already optimized and overclocked.
You can check the history in this thread, too. :)
viewtopic.php?f=93&t=27117
These users thanked the author joy for the post:
sgudla (Sat Jan 04, 2020 6:58 am)

sgudla
Posts: 3
Joined: Fri Jan 03, 2020 9:17 am
languages_spoken: english
Has thanked: 4 times
Been thanked: 0
Contact:

Re: Overclock RAM Speed

Unread post by sgudla » Sat Jan 04, 2020 6:57 am

Hi,

Thank you for the replies. I was going through the link viewtopic.php?f=93&t=27117, i see that for XU4, @joy you have added 933MHz frequency.
In order to add a custom frequency, could you help me with the steps required? (if its possible).

PS: I am not looking to get the maximum performance, i am only looking for a way to change the latency values and by changing the frequency if we can achieve it, i wanted to know how to do it?

sgudla
Posts: 3
Joined: Fri Jan 03, 2020 9:17 am
languages_spoken: english
Has thanked: 4 times
Been thanked: 0
Contact:

Re: Overclock RAM Speed

Unread post by sgudla » Sat Jan 04, 2020 9:45 am

Hi @joy,

In the link https://github.com/hardkernel/linux/blo ... mif.c#L208 for 933MHz there are 3 values as shown below:
{0x3D6BA816, 0x4742086E, 0x60670447}, /*933Mhz*/

I have a couple of questions on them:
1. How do we get these values?
2. do these values set some registers on the memory device?

I was going through the JEDEC spec for LPDDR5 and under the section Mode Register Definition - they have some registers defined to set tWL and tRL. Can these be programmed?

I am a newbie and trying to figure out how it works. Thank you for the help.

joy
Posts: 993
Joined: Fri Oct 02, 2015 1:44 pm
languages_spoken: english
ODROIDs: ODROID-C1+, XU4, X
Has thanked: 39 times
Been thanked: 94 times
Contact:

Re: Overclock RAM Speed

Unread post by joy » Mon Jan 06, 2020 9:33 am

Hi sgudla,

For the table, I found the values of timingRow, timingData and timingPower from one of existing Exynos mif drivers in kernel 3.10.y.
https://github.com/hardkernel/linux/blo ... if.c#L2399
So I have no idea how to configure the specific value of the registers.

I thought exynos5320 DMC IP may be from a same branch with exynos5422 because registers configurations are same
then, I did put various kinds of tests and confirmed it.

And as I mentioned, we don't have detailed materials and I think it may be samsung confidential parts.
I'm sorry I didn't help. :(
These users thanked the author joy for the post:
sgudla (Tue Jan 07, 2020 8:45 am)

Post Reply

Return to “Android”

Who is online

Users browsing this forum: No registered users and 2 guests