[U-Boot] Uboot warm reset

[Brent Bartson]

Hello,

We have an MPC7448/TSI109 based embedded design that utilizes uboot as the bootloader. The problem is that once Linux boots, if you issue a 'reboot' from Linux, it hangs the system (it required a power-down to reset the board). This same behavior can be seen if you issue 'reset' from the uboot prompt. Looking into the uboot code I could see that it was toggling the MasterReset (MR) line (GPIO) out of the Tundra TSI109. This MR signal was not resetting the cpu properly.

I've found some uboot reset code from the Tundra site that handles reset differently (not using MR now) and it solves one aspect of this problem. Now when I issue reset is does not foul the hardware so badly that it requires a hard power-cycle to recover. Now the board can be 'soft-reset' from the host processor via PCI_RST (over the PCI bus via the Tundra bridge).

My current goal is to get the 'reset' command from within uboot to do a soft reset and re-initialize uboot automatically. Can anyone provide some advice in this area? Am I possibly overlooking some CONFIG option in the build of uboot?

Regards,
Brent