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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: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Lubomir Rintel 2013-12-22 11:34:22 +01:00 committed by Stefan Richter
parent a9954ce769
commit 8bc588e0e5
3 changed files with 12 additions and 22 deletions
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4
Documentation/debugging-via-ohci1394.txt
View File

@ -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

19
drivers/firewire/ohci.c
View File

@ -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
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_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)

11
lib/Kconfig.debug
View File

@ -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