[U-Boot] [PATCH v1 1/2] odroid: Update README with USB host information

[Suriyan Ramasami]

Hello Przemyslaw,

On Wed, Nov 19, 2014 at 9:39 AM, Przemyslaw Marczak
<p.marczak at samsung.com> wrote:
> Hello,
>
> On 11/19/2014 05:21 PM, Suriyan Ramasami wrote:
>>
>> Add information wrt the USB host side of things for the Odroid-U2/U3 and
>> the
>> Odroid-X/X2
>>
>> Signed-off-by: Suriyan Ramasami <suriyan.r at gmail.com>
>> ---
>>
>> Changes in v1:
>> - Add USB host notes for the Odroid
>>
>>   doc/README.odroid | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 48 insertions(+)
>>
>> diff --git a/doc/README.odroid b/doc/README.odroid
>> index 528bb95..0eaf3ff 100644
>> --- a/doc/README.odroid
>> +++ b/doc/README.odroid
>> @@ -141,3 +141,51 @@ And the boot sequence is:
>>   - boot_fit - if "Image.itb" exists
>>   - boot_zimg - if "zImage" exists
>>   - boot_uimg - if "uImage" exists
>> +
>> +11. USB host support
>> +====================
>> +The Odroid-X/X2 have the below schematics wrt USB:
>> +
>> +Exynos USB_HOST1 -> USB3503 HUB ----> LAN9514 USB HUB -----> LAN9514
>> Ethernet
>> +                       |               |
>> +                       |               +-------Host1---------> USB port
>> +                       |               |
>> +                       |               +-------Host2---------> USB port
>> +                       |               |
>> +                       |               +-------Host3---------> USB port
>> +                       |               |
>> +                       |               +-------Host4---------> USB port
>> +                       |
>> +                       +-------------------------------------> USB port
>> +                       |
>> +                       +-------------------------------------> USB port
>> +
>> +The Odroid-U2/U3 have the below schematics wrt USB:
>> +
>> +Exynos HSIC1 -----------------------------------------------> LAN9514
>> Ethernet
>> +
>> +Exynos HSIC2 -----> USB3503A HUB ---------------Host1---------> USB port
>> +                       |
>> +                       +-----------------------Host2---------> USB port
>> +                       |
>> +                       +-----------------------HOst3---------> USB port
>> (U3)
>> +
>> +The HSICs are used in the case of the Odroid-Us and the USB Host in the
>> SoC
>> +is used in the case of the Odroid-Xs.
>> +
>> +In drivers/usb/host/ehci-exynos.c, function names starting with
>> exysno4412*
>> +have been added to initialize the HSICs and the PHYs.
>> +
>> +In board/samsung/odroid/odroid.c, function board_usb_init() adds code to
>> +initialize the USB3503 hub.
>> +The initializing of the USB3503 hub is as defined in the USB3503A spec
>> sheet.
>> +Please refer to Figure 4.1 in the Datasheet.
>> +a) Set the INT_N (X30) low (Odroid-Us) or high (Odroid-Xs). This is so
>> that the
>> +correct REFCLK frequency is selected. 24MHz for Odroid Us and 26MHz for
>> Odroid
>> +Xs.
>> +b) Disconnect the HUB (Set HUB_CONNECT (X34) to 0)
>> +c) Reset the HUB (Set RESET_N (X35) to 0 and then to 1)
>> +d) HUB waits for REF_CLK (which we have set appropriately)
>> +e) Timeout waiting for HUB configuration stage
>> +f) Connect the HUB (Set HUB_CONNECT (X34) to 1)
>> +g) Power recycle the LAN9730 which is connected to BUCK8 (Odroid Us)
>>
>
> Suriyan, you quite misunderstand my intention. You added really useful part
> of code - now user can read/write data to USB mass storage or boot over the
> Ethernet. Probably you are using this feature. And this is a usage of the
> USB for the user.
>
> For the user - it's not important how it works in the hardware - I would
> like to get some simple instructions, e.g. How to boot Odroid over the
> Ethernet, or how to write data to USB stick. I believe that users read this
> documentation when they starting use of Odroid with the mainline U-Boot, and
> a description of another boot option is welcome here.
> It should be "How to start with this board", rather than how to develop USB
> hub driver on it.
>

Ah! I see. You are right, I totally misunderstood you. I shall get rid
of the hardware part of things, and add the sections that you have
mentioned, viz:
- How to boot Odroid over Ethernet
- How to boot Odroid over USB storage etc

Thanks
- Suriyan

> Best regards,
> --
> Przemyslaw Marczak
> Samsung R&D Institute Poland
> Samsung Electronics
> p.marczak at samsung.com