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Commit 8bc588e0 authored by Lubomir Rintel's avatar Lubomir Rintel Committed by Stefan Richter
Browse files

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 <dave.hansen@linux.intel.com>
Signed-off-by: default avatarLubomir Rintel <lkundrak@v3.sk>
Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
parent a9954ce7

Documentation/debugging-via-ohci1394.txt

+1 −3
Original line number Diff line number Diff line
@@ -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

drivers/firewire/ohci.c

+11 −8
Original line number Diff line number Diff line
@@ -370,6 +370,10 @@ MODULE_PARM_DESC(debug, "Verbose logging (default = 0" 
	", 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_struct *work) 
			  be32_to_cpu(ohci->next_header));

	}



#ifdef CONFIG_FIREWIRE_OHCI_REMOTE_DMA

	if (param_remote_dma) {

		reg_write(ohci, OHCI1394_PhyReqFilterHiSet, ~0);

		reg_write(ohci, OHCI1394_PhyReqFilterLoSet, ~0);

#endif

	}



	spin_unlock_irq(&ohci->lock);
@@ -2587,13 +2591,13 @@ 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, 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 fw_card *card, 
	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)

lib/Kconfig.debug

+0 −11
Original line number Diff line number Diff line
@@ -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