| Nico Huber | b0f8326 | 2014-01-01 20:47:55 +0100 | [diff] [blame] | 1 | |
| 2 | uio_usbdebug - Run coreboot's usbdebug driver in userspace |
| 3 | ========================================================== |
| 4 | |
| 5 | |
| 6 | ## Purpose |
| 7 | |
| 8 | uio_usbdebug enables you to debug coreboot's usbdebug driver inside a |
| 9 | running operating system (only Linux at this time). This comes very |
| 10 | handy if you're hacking the usbdebug driver and don't have any other |
| 11 | debug output from coreboot itself. |
| 12 | |
| 13 | |
| 14 | ## State |
| 15 | |
| 16 | Currently only Intel chipsets are supported. Support for other chipsets |
| 17 | should be straightforward (normally just some port-enable code has to |
| 18 | be implemented). |
| 19 | |
| 20 | The Linux kernel driver (see linux/uio_ehci_pci.c) has only one PCI ID |
| 21 | hardcoded (for ICH7). The whole setup has been developed and tested on |
| 22 | a ThinkPad T60. |
| 23 | |
| 24 | ### Files |
| 25 | |
| 26 | uio_usbdebug.c - The userspace part of the uio interface. |
| 27 | |
| 28 | uio_usbdebug_intel.c - Port enable code for Intel chipsets. |
| 29 | |
| 30 | linux/uio_ehci_pci.c - Kernel part of the uio interface. |
| 31 | |
| 32 | console/printk.c - A do_printk() implementation so you can see debug |
| 33 | output with CONFIG_DEBUG_USBDEBUG enabled. |
| 34 | |
| 35 | device/*.c lib/*.c - Some stubs for (hopefully) unneeded functions for |
| 36 | proper linking. |
| 37 | |
| 38 | |
| 39 | ## Usage |
| 40 | |
| 41 | ### Preparations |
| 42 | |
| 43 | The MMIO space has to be a whole 4K page in size and alignment to be |
| 44 | mapped into userspace. This is very uncommon, so you'll most probably |
| 45 | have to remap the MMIO space. The Linux kernel does that for you with |
| 46 | the `pci=resource_alignment=<pci address>` kernel parameter (e.g. |
| 47 | `pci=resource_alignment=0:1d.7` for ICH7). |
| 48 | |
| 49 | If your PCI device isn't listed in the kernel driver yet, you might want |
| 50 | to add it to the `ehci_pci_ids` table in `linux/uio_ehci_pci.c` (or do |
| 51 | some module alias magic if you know how to). |
| 52 | |
| 53 | ### Build / Install |
| 54 | |
| 55 | Somehow like this: |
| 56 | |
| 57 | $ # Configure coreboot for your board and enable CONFIG_USBDEBUG |
| 58 | $ make menuconfig |
| 59 | $ cd util/uio_usbdebug/ |
| 60 | $ make -Clinux/ |
| 61 | $ sudo make -Clinux/ install |
| 62 | $ make |
| 63 | |
| 64 | ### Run |
| 65 | |
| 66 | $ # Unload Linux' EHCI driver (high-speed devices will stop working) |
| 67 | $ sudo modprobe -r ehci-pci |
| 68 | $ # Load the uio driver |
| 69 | $ sudo modprobe uio-ehci-pci |
| 70 | $ # Find your uio device |
| 71 | $ ls /sys/module/uio_ehci_pci/drivers/*/*/uio/ |
| 72 | uio0 |
| 73 | $ # Run uio_usbdebug on this device |
| 74 | $ sudo ./uio_usbdebug /dev/uio0 |
| 75 | |
| 76 | Sadly, uio_usbdebug has to be run with root privileges since there are |
| 77 | port-80 writes in the usbdebug driver. |