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Use TMS320C6678 to access SSD

Other Parts Discussed in Thread: TMS320C6678

My application is to use TMS320C6678 to access SSD and I choose Marvell 88SE9230 as SATA Host Controller.

The TMS320C6678 can access 88SE9230 through 2 lanes PCIE at 5.0Gbps.

Here is my question:

1.My write and read speed requirement is above 450MBps,is it possible with one SSD?(The SSD can meet that requirement and I use Linux)

2.If the requirement can not be met  due to the filesystem,how about use Raid?(like Raid 0,using 2 SSD) 

3.As  88SE9230 can support hardware Raid,should I write my own Raid driver or just access the Raid through ahci platform?

  • Hi,

    We do not have any sample designs that are using the 88SE9230. In addition the information on the 88SE9230 is only available through an NDA with marvell.  Since I have no data on the part, I'm afraid that I can't answer your questions. Information on the through-put for the PCIE interface can be found in the Throughput Performance Guide for C66x KeyStone Devices (Rev. A) located in the C6678 page on TI.com.

    Regards, Bill

  • Thanks Bill,

    Are there any sample designs about my application?

    I have checked the Throughput Performance Guide for C66x KeyStone Devices (Rev. A) and found that the PCIE  Throughput can meet my requirement.

    But I still have the question about the Raid.

    I have checked the TI SATA Wiki.

    It is said that if you use a hardware Raid,you can change the Raid Controller to Raid mode on PC,

    and then use the ahci to access it directly.

    I get a little confused about that.

    The orignial text is "

    Do we support external hardware RAID

    External hardware RAID is a blackbox for us. Usually external RAID storage tower vendors provide RAID configuration tool. These are either x86 Windows or x86 Linux host based software tool. Either we have to port these tools to ARM Linux (DM81XX) or we have to use a pre-configured external RAID storage. During our testing we configured RAID devices from Windows XP host for RAID-0 & JBOD and used it with our platform."

  • Hi Xiao,

    The wiki that you are referring to is for the software release to support the DM81xx components. To my knowledge, the software release for the KeyStone I devices does not support SATA. I'll ask the software team but the comments that you have included from the DM81XX SATA wiki do not apply to the C6678.

    Regards, Bill

  • Thanks Bill,

    I just wonder if I can port the TI AHCI platform to C6678 EVM Linux.

    Because I can't access the SSD through SATA without AHCI.

    Then I can use C6678 EVM to test my application.

  • Hi, Xiao Peng,

    TI developer tested in the past a RevoDrive SSD with the same throughput on a PC and on C6678 EVM (~180MB/s) but we think it was limited to a 200MB/s of theoretical performances.

    About raid support,  if the SSD has a dedicated Linux driver which leverage the hw raid 0, you can use it. Otherwise, you will need to use the Linux generic SATA support through the AHCI driver without any hw raid support or develop your own driver.

    It seems that the 88SE9230 has no specific Linux driver in either 2.6.34 or in recent kernel (thus no hw raid 0 capability in Linux).

    Moreover generally Marvell does not provide the information on how programming their devices, so you cannot easily create your own one driver.

    Rex

  • Thank you very much,Rex

    Whicn one shoud be the bottleneck of the "theoretical performances" you mentioned above ?

    The throughput of the PCIE , SSD and SATA Host Controller ?

    I have checked the throughput I listed and I think they can meet my requirement.

    The efficiency of the filesystem is that I can not be sure about.

    Which one is used in that test, the filesystem or raw data ?

     

  • Hi Xiao peng,

                May I know which Linux version you're used to connect Marvell 88SE9230 for SATA read/write ? I encountered SATA link down issue when connecting 66AK2E PCIe with Marvell 88SE9235, it will be great help if you can shre me some info hot to make SATA work. 

                Thanks very much! 

                 Jane