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firewire: fw-ohci: add option for remote debugging
This way firewire-ohci can be used for remote debugging like ohci1394. Version with amendment from Fri, 11 Apr 2008 00:08:08 +0200. Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Acked-by: Bernhard Kaindl <bk@suse.de>
Showing 3 changed files with 31 additions and 7 deletions Side-by-side Diff
Documentation/debugging-via-ohci1394.txt
| ... | ... | @@ -41,15 +41,19 @@ |
| 41 | 41 | This can be turned off by ohci1394's module parameter phys_dma=0. |
| 42 | 42 | |
| 43 | 43 | The alternative firewire-ohci driver in drivers/firewire uses filtered physical |
| 44 | -DMA, hence is not yet suitable for remote debugging. | |
| 44 | +DMA by default, which is more secure but not suitable for remote debugging. | |
| 45 | +Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA (Kernel hacking menu: | |
| 46 | +Remote debugging over FireWire with firewire-ohci) to get unfiltered physical | |
| 47 | +DMA. | |
| 45 | 48 | |
| 46 | -Because ohci1394 depends on the PCI enumeration to be completed, an | |
| 47 | -initialization routine which runs pretty early (long before console_init() | |
| 48 | -which makes the printk buffer appear on the console can be called) was written. | |
| 49 | +Because ohci1394 and firewire-ohci depend on the PCI enumeration to be | |
| 50 | +completed, an initialization routine which runs pretty early has been | |
| 51 | +implemented for x86. This routine runs long before console_init() can be | |
| 52 | +called, i.e. before the printk buffer appears on the console. | |
| 49 | 53 | |
| 50 | 54 | To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: |
| 51 | -Provide code for enabling DMA over FireWire early on boot) and pass the | |
| 52 | -parameter "ohci1394_dma=early" to the recompiled kernel on boot. | |
| 55 | +Remote debugging over FireWire early on boot) and pass the parameter | |
| 56 | +"ohci1394_dma=early" to the recompiled kernel on boot. | |
| 53 | 57 | |
| 54 | 58 | Tools |
| 55 | 59 | ----- |
drivers/firewire/fw-ohci.c
| ... | ... | @@ -1097,6 +1097,11 @@ |
| 1097 | 1097 | reg_write(ohci, OHCI1394_ConfigROMhdr, ohci->next_header); |
| 1098 | 1098 | } |
| 1099 | 1099 | |
| 1100 | +#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA | |
| 1101 | + reg_write(ohci, OHCI1394_PhyReqFilterHiSet, ~0); | |
| 1102 | + reg_write(ohci, OHCI1394_PhyReqFilterLoSet, ~0); | |
| 1103 | +#endif | |
| 1104 | + | |
| 1100 | 1105 | spin_unlock_irqrestore(&ohci->lock, flags); |
| 1101 | 1106 | |
| 1102 | 1107 | if (free_rom) |
| ... | ... | @@ -1435,6 +1440,9 @@ |
| 1435 | 1440 | static int |
| 1436 | 1441 | ohci_enable_phys_dma(struct fw_card *card, int node_id, int generation) |
| 1437 | 1442 | { |
| 1443 | +#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA | |
| 1444 | + return 0; | |
| 1445 | +#else | |
| 1438 | 1446 | struct fw_ohci *ohci = fw_ohci(card); |
| 1439 | 1447 | unsigned long flags; |
| 1440 | 1448 | int n, retval = 0; |
| ... | ... | @@ -1466,6 +1474,7 @@ |
| 1466 | 1474 | out: |
| 1467 | 1475 | spin_unlock_irqrestore(&ohci->lock, flags); |
| 1468 | 1476 | return retval; |
| 1477 | +#endif /* CONFIG_FIREWIRE_OHCI_REMOTE_DMA */ | |
| 1469 | 1478 | } |
| 1470 | 1479 | |
| 1471 | 1480 | static u64 |
lib/Kconfig.debug
| ... | ... | @@ -593,7 +593,7 @@ |
| 593 | 593 | to find out which userspace is blocking on what kernel operations. |
| 594 | 594 | |
| 595 | 595 | config PROVIDE_OHCI1394_DMA_INIT |
| 596 | - bool "Provide code for enabling DMA over FireWire early on boot" | |
| 596 | + bool "Remote debugging over FireWire early on boot" | |
| 597 | 597 | depends on PCI && X86 |
| 598 | 598 | help |
| 599 | 599 | If you want to debug problems which hang or crash the kernel early |
| ... | ... | @@ -620,6 +620,17 @@ |
| 620 | 620 | in charge of the OHCI-1394 controllers should be used instead. |
| 621 | 621 | |
| 622 | 622 | See Documentation/debugging-via-ohci1394.txt for more information. |
| 623 | + | |
| 624 | +config FIREWIRE_OHCI_REMOTE_DMA | |
| 625 | + bool "Remote debugging over FireWire with firewire-ohci" | |
| 626 | + depends on FIREWIRE_OHCI | |
| 627 | + help | |
| 628 | + This option lets you use the FireWire bus for remote debugging | |
| 629 | + with help of the firewire-ohci driver. It enables unfiltered | |
| 630 | + remote DMA in firewire-ohci. | |
| 631 | + See Documentation/debugging-via-ohci1394.txt for more information. | |
| 632 | + | |
| 633 | + If unsure, say N. | |
| 623 | 634 | |
| 624 | 635 | source "samples/Kconfig" |