Re: [U-Boot] mpc5121 - EHCI problems with some (but not all) USB hubs

25 Sep 2009


      On Fri, Sep 25, 2009 at 2:04 AM, Michael Trimarchi
trimarchi@gandalf.sssup.it wrote:
...
Damien Dusha wrote:
...
Dear All,
I am attempting to integrate the USB on the Freescale mpc5121
processor on the mpc5121ads board from Silicon Turnkey for upgrades of
kernel, u-boot etc.
I have succeeded in integrating Francesco Rendine 's EHCI patch for
the MPC5121 (see
http://lists.denx.de/pipermail/u-boot/2009-June/055021.html ) and I
have the general functionality of upgrading from a USB stick working
straight from the USB, or through some (but not all) USB hubs.
However, I am having problem using the driver with some (but not all)
USB hubs.   I have some USB hubs that work "out of the box", but I
have other hubs that cause booting u-boot to hang after attempting to
initialise the USB.  The ones that do work, and the ones that fail all
fail in the same place the great majority of the time (they succeed
very occasionally).
I have traced the hang to the following lines in
drivers/usb/host/ehci-hcd.c:
/* Wait for TDs to be processed. */
       ts = get_timer(0);
       vtd = td;
       do {
               /* Invalidate dcache */
               ehci_invalidate_dcache(&qh_list);
               token = hc32_to_cpu(vtd->qt_token);
               if (!(token & 0x80))
                       break;
/* This was my own line I added to check.  The
get_timer(ts) always returns 0 and never exits the loop */
              debug("get_timer: %d, CONFIG_SYS_HZ: %d\n",
get_timer(ts), CONFIG_SYS_HZ);
       } while (get_timer(ts) < CONFIG_SYS_HZ);
I think that the git_timer is not proprer implemented here and so
what happen if you go out the busy loop and return an error to the
message?
Can you try on another hardware with u-boot?
Yesterday, we tried the following:
/* Add long delay before entering the loop */
    udelay(10000);
/* Wait for TDs to be processed. */
    /* Remove the loop and exit immediately. Do not wait for timer */
    // ts = get_timer(0);
    //vtd = td;
    //do {
    	/* Invalidate dcache */
    	ehci_invalidate_dcache(&qh_list);
    	token = hc32_to_cpu(vtd->qt_token);
    //	if (!(token & 0x80))
    //		break;
// debug("get_timer: %d, CONFIG_SYS_HZ: %d\n", get_timer(ts),
CONFIG_SYS_HZ);
    //} while (get_timer(ts) < CONFIG_SYS_HZ);
With the following result:
 * If only "working" hubs and a USB stick is attached, it will do our
auto upgrade sequence as normal.
 * If a "broken" hub is present, U-Boot will report that the devices
are found, but will not actually read a USB stick attached to the hub.
  It will not read a stick, even if the stick is attached to a
"working" hub, and the "broken" hub is cascaded off the working hub.
Unfortunately, I have no other EHCI hardware available - only a
5200LITE and a AVR32 dev board in the back of the cupboard somewhere.
-- Damien.