[U-Boot] twister: usb host support

[Tapani]

Stefano, Jeroen,


On Wed, 10 Jul 2013 18:04:04 +0200
Jeroen Hofstee <jeroen at myspectrum.nl> wrote:

> Hello Stefano / Tapani,
> 
> On 07/10/2013 04:27 PM, Stefano Babic wrote:
> > On 09/07/2013 21:46, Jeroen Hofstee wrote:
> >> I cannot find any document mentioning gpio_25 though.
> >> Any reason for this usage?
> > That is right. There is no written documentation by Technexion about
> > this pin. I have added in CC Tapani, maybe he can tell us something more.
> > The GPIO is used internally on the TAM3517 SOM, and we have no
> > schematics about it. We have to guess about its usage.
> 
> Yes, and some clarification of the pin 35 would be
> appreciated as well, since it is marked as ball X, I guess
> it is controlled by hardware and the hub cannot be reset
> from software, but that is just guessing...
> 
> > The reason to have it is that the sources for the kernel provided by
> > Technexion (an ancient 2.6.32 Version) set this pin to reset the EHCI.
> > As I said, there is no further documentation and rather we can only make
> > some supposition. The usage in U-Boot then reflects the usage made by
> > Technexion.
> >
> 
> Fyi my linux copy (3.7) with this gpio set as the phy_reset is also
> unable to properly reset it and times out. The usb is working
> though, also without a proper reset..
> 
> >> p.s.
> >> I found by sheer accidence that the usb is behaving
> >> completely normal (after the patch) on rev B1. It is
> >> broken on rev B without the patch and working buggy
> >> with it. On rev B1 + patch the USB to SATA converter
> >> is discovered as well, which I have never seen before.
> >>
> > I can confirm issues with version B of the TAM3517-SOM. I am testing a
> > B1 SOM with a B twister. I do not know the details about changelog
> > between B and B1 version of the SOM, but I got both USB and Ethernet
> > problems with TAM3517-B. The same image runs without the same problems
> > on a B1.
> 
> ok, good to know.
> 
> > There is also this pending patch by Michael:
> >
> > http://patchwork.ozlabs.org/patch/250290/
> >
> > It is applied to u-boot-ti, not yet to mainline.
> >
> 
> on top of usb master this patch leads to:
> USB0:    ULPI: ulpi_reset: failed writing reset bit
> ULPI:    ulpi_reset: failed writing reset bit
> 
> It does always find the stick though and never the SATA converter.
> 
> without the gpio_25 reset, the second error goes away and
> the SATA is back.
> 
> >
> > @@ -92,9 +92,6 @@ int board_init(void)
> >       enable_gpmc_cs_config(gpmc_XR16L2751, &gpmc_cfg->cs[3],
> >           XR16L2751_UART2_BASE, GPMC_SIZE_16M);
> >
> > -    gpio_request(CONFIG_OMAP_EHCI_PHY1_RESET_GPIO, "USB_PHY1_RESET");
> > -    gpio_direction_output(CONFIG_OMAP_EHCI_PHY1_RESET_GPIO, 1);
> > -
> > See my concerns above. Do not reset the hub in the kernel ?
> 
> I don't get the last part, but feedback from Technexion is
> needed first to remove all the guess, maybe etc. If it has a
> valid function, not setting it's value might not be such a
> good idea...
>

GPIO_25 is indeed USB PHY reset. (Pull low to reset). 

regards,
 
//Tapani