Bug 225713
| Summary: | Zynq/Zedboard GPIO driver can reset USB port on some boards | ||||||
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| Product: | Base System | Reporter: | Thomas Skibo <thoma555-bsd> | ||||
| Component: | arm | Assignee: | Oleksandr Tymoshenko <gonzo> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Only Me | CC: | gonzo | ||||
| Priority: | --- | Keywords: | patch | ||||
| Version: | CURRENT | ||||||
| Hardware: | arm | ||||||
| OS: | Any | ||||||
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A commit references this bug: Author: gonzo Date: Tue Apr 3 04:31:55 UTC 2018 New revision: 331906 URL: https://svnweb.freebsd.org/changeset/base/331906 Log: Fix accidental USB port resets by GPIO on Zynq/Zedboard boards The Zynq/Zedboard GPIO driver attempts to tri-state all GPIO pins on boot up but the order in which I reset the hardware can cause the pins to be briefly held low before being tri-stated. This is a problem on boards that use GPIO pins to reset devices. In particular, the Zybo and ZC-706 boards use a GPIO pin as a USB PHY reset. If U-boot enables the USB port before booting the kernel, the GPIO driver attach causes a glitch on the USB PHY reset and the USB port loses power. My fix is to have the GPIO driver leave the pins in whatever configuration U-boot placed them. PR: 225713 Submitted by: Thomas Skibo <thoma555-bsd@yahoo.com> MFC after: 1 week Changes: head/sys/arm/xilinx/zy7_gpio.c A commit references this bug: Author: gonzo Date: Tue May 15 02:26:50 UTC 2018 New revision: 333619 URL: https://svnweb.freebsd.org/changeset/base/333619 Log: MFC r331906: Approved by: re (gjb) Fix accidental USB port resets by GPIO on Zynq/Zedboard boards The Zynq/Zedboard GPIO driver attempts to tri-state all GPIO pins on boot up but the order in which I reset the hardware can cause the pins to be briefly held low before being tri-stated. This is a problem on boards that use GPIO pins to reset devices. In particular, the Zybo and ZC-706 boards use a GPIO pin as a USB PHY reset. If U-boot enables the USB port before booting the kernel, the GPIO driver attach causes a glitch on the USB PHY reset and the USB port loses power. My fix is to have the GPIO driver leave the pins in whatever configuration U-boot placed them. PR: 225713 Submitted by: Thomas Skibo <thoma555-bsd@yahoo.com> Changes: _U stable/11/ stable/11/sys/arm/xilinx/zy7_gpio.c |
Created attachment 190368 [details] patch for sys/arm/xilinx/zy7_gpio.c The Zynq/Zedboard GPIO driver attempts to tri-state all GPIO pins on boot up but the order in which I reset the hardware can cause the pins to be briefly held low before being tri-stated. This is a problem on boards that use GPIO pins to reset devices. In particular, the Zybo and ZC-706 boards use a GPIO pin as a USB PHY reset. If U-boot enables the USB port before booting the kernel, the GPIO driver attach causes a glitch on the USB PHY reset and the USB port loses power. My fix is to have the GPIO driver leave the pins in whatever configuration U-boot placed them.