Date: Sun, 22 Dec 2013 11:34:22 +0100 From: Lubomir Rintel Subject: firewire: ohci: Turn remote DMA support into a module parameter This makes it possible to debug kernel over FireWire without the need to recompile it. [Stefan R: changed description from "...0" to "...N"] Cc: Dave Hansen Signed-off-by: Lubomir Rintel Signed-off-by: Stefan Richter --- Documentation/debugging-via-ohci1394.txt | 4 +--- drivers/firewire/ohci.c | 19 +++++++++++-------- lib/Kconfig.debug | 11 ----------- 3 files changed, 12 insertions(+), 22 deletions(-) --- a/Documentation/debugging-via-ohci1394.txt +++ b/Documentation/debugging-via-ohci1394.txt @@ -38,9 +38,7 @@ Drivers The firewire-ohci driver in drivers/firewire uses filtered physical 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. +Pass the remote_dma=1 parameter to the driver to get unfiltered physical DMA. Because the firewire-ohci driver depends on the PCI enumeration to be completed, an initialization routine which runs pretty early has been --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -370,6 +370,10 @@ MODULE_PARM_DESC(debug, "Verbose logging ", busReset events = " __stringify(OHCI_PARAM_DEBUG_BUSRESETS) ", or a combination, or all = -1)"); +static bool param_remote_dma; +module_param_named(remote_dma, param_remote_dma, bool, 0444); +MODULE_PARM_DESC(remote_dma, "Enable unfiltered remote DMA (default = N)"); + static void log_irqs(struct fw_ohci *ohci, u32 evt) { if (likely(!(param_debug & @@ -2050,10 +2054,10 @@ static void bus_reset_work(struct work_s be32_to_cpu(ohci->next_header)); } -#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA - reg_write(ohci, OHCI1394_PhyReqFilterHiSet, ~0); - reg_write(ohci, OHCI1394_PhyReqFilterLoSet, ~0); -#endif + if (param_remote_dma) { + reg_write(ohci, OHCI1394_PhyReqFilterHiSet, ~0); + reg_write(ohci, OHCI1394_PhyReqFilterLoSet, ~0); + } spin_unlock_irq(&ohci->lock); @@ -2587,13 +2591,13 @@ static int ohci_cancel_packet(struct fw_ 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, ret = 0; + if (param_remote_dma) + return 0; + /* * FIXME: Make sure this bitmask is cleared when we clear the busReset * interrupt bit. Clear physReqResourceAllBuses on bus reset. @@ -2622,7 +2626,6 @@ static int ohci_enable_phys_dma(struct f spin_unlock_irqrestore(&ohci->lock, flags); return ret; -#endif /* CONFIG_FIREWIRE_OHCI_REMOTE_DMA */ } static u32 ohci_read_csr(struct fw_card *card, int csr_offset) --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1547,17 +1547,6 @@ 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. - config BUILD_DOCSRC bool "Build targets in Documentation/ tree" depends on HEADERS_CHECK