diff options
| -rw-r--r-- | Documentation/debugging-via-ohci1394.txt | 16 | ||||
| -rw-r--r-- | drivers/firewire/fw-ohci.c | 9 | ||||
| -rw-r--r-- | lib/Kconfig.debug | 13 |
3 files changed, 31 insertions, 7 deletions
diff --git a/Documentation/debugging-via-ohci1394.txt b/Documentation/debugging-via-ohci1394.txt index c360d4e91b48..59a91e5c6909 100644 --- a/Documentation/debugging-via-ohci1394.txt +++ b/Documentation/debugging-via-ohci1394.txt @@ -41,15 +41,19 @@ to a working state and enables physical DMA by default for all remote nodes. This can be turned off by ohci1394's module parameter phys_dma=0. The alternative firewire-ohci driver in drivers/firewire uses filtered physical -DMA, hence is not yet suitable for remote debugging. +DMA by default, which is more secure but not suitable for remote debugging. +Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA (Kernel hacking menu: +Remote debugging over FireWire with firewire-ohci) to get unfiltered physical +DMA. -Because ohci1394 depends on the PCI enumeration to be completed, an -initialization routine which runs pretty early (long before console_init() -which makes the printk buffer appear on the console can be called) was written. +Because ohci1394 and firewire-ohci depend on the PCI enumeration to be +completed, an initialization routine which runs pretty early has been +implemented for x86. This routine runs long before console_init() can be +called, i.e. before the printk buffer appears on the console. To activate it, enable CONFIG_PROVIDE_OHCI1394_DMA_INIT (Kernel hacking menu: -Provide code for enabling DMA over FireWire early on boot) and pass the -parameter "ohci1394_dma=early" to the recompiled kernel on boot. +Remote debugging over FireWire early on boot) and pass the parameter +"ohci1394_dma=early" to the recompiled kernel on boot. Tools ----- diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c index 07d6053ff57e..5da7c6715e1e 100644 --- a/drivers/firewire/fw-ohci.c +++ b/drivers/firewire/fw-ohci.c @@ -1097,6 +1097,11 @@ static void bus_reset_tasklet(unsigned long data) reg_write(ohci, OHCI1394_ConfigROMhdr, ohci->next_header); } +#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA + reg_write(ohci, OHCI1394_PhyReqFilterHiSet, ~0); + reg_write(ohci, OHCI1394_PhyReqFilterLoSet, ~0); +#endif + spin_unlock_irqrestore(&ohci->lock, flags); if (free_rom) @@ -1435,6 +1440,9 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet) static int ohci_enable_phys_dma(struct fw_card *card, int node_id, int generation) { +#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA + return 0; +#else struct fw_ohci *ohci = fw_ohci(card); unsigned long flags; int n, retval = 0; @@ -1466,6 +1474,7 @@ ohci_enable_phys_dma(struct fw_card *card, int node_id, int generation) out: spin_unlock_irqrestore(&ohci->lock, flags); return retval; +#endif /* CONFIG_FIREWIRE_OHCI_REMOTE_DMA */ } static u64 diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 0796c1a090c0..78955eb6bd94 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -593,7 +593,7 @@ config LATENCYTOP to find out which userspace is blocking on what kernel operations. config PROVIDE_OHCI1394_DMA_INIT - bool "Provide code for enabling DMA over FireWire early on boot" + bool "Remote debugging over FireWire early on boot" depends on PCI && X86 help If you want to debug problems which hang or crash the kernel early @@ -621,4 +621,15 @@ config PROVIDE_OHCI1394_DMA_INIT See Documentation/debugging-via-ohci1394.txt for more information. +config FIREWIRE_OHCI_REMOTE_DMA + bool "Remote debugging over FireWire with firewire-ohci" + depends on FIREWIRE_OHCI + help + This option lets you use the FireWire bus for remote debugging + with help of the firewire-ohci driver. It enables unfiltered + remote DMA in firewire-ohci. + See Documentation/debugging-via-ohci1394.txt for more information. + + If unsure, say N. + source "samples/Kconfig" |