I grab this opportunity to ask the list: Would you prefer the remote
debugging option in the kernel hacking menu (as in the commit), or
rather in the respective driver submenu?
For reference:
Date: Thu, 28 Feb 2008 20:54:43 +0100 (CET)
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
Subject: firewire: fw-ohci: add option for remote debugging
This way firewire-ohci can be used for remote debugging like ohci1394.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
Documentation/debugging-via-ohci1394.txt | 13 ++++++++-----
drivers/firewire/fw-ohci.c | 9 +++++++++
lib/Kconfig.debug | 10 ++++++++++
3 files changed, 27 insertions(+), 5 deletions(-)
Index: linux/Documentation/debugging-via-ohci1394.txt
===================================================================
--- linux.orig/Documentation/debugging-via-ohci1394.txt
+++ linux/Documentation/debugging-via-ohci1394.txt
@@ -41,11 +41,14 @@ to a working state and enables physical
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.
-
-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.
+DMA by default, which is more secure but not suitable for remote debugging.
+Compile the driver with CONFIG_FIREWIRE_OHCI_REMOTE_DMA to get unfiltered
+physical DMA.
+
+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
Index: linux/drivers/firewire/fw-ohci.c
===================================================================
--- linux.orig/drivers/firewire/fw-ohci.c
+++ linux/drivers/firewire/fw-ohci.c
@@ -1097,6 +1097,11 @@ static void bus_reset_tasklet(unsigned l
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_
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 *car
out:
spin_unlock_irqrestore(&ohci->lock, flags);
return retval;
+#endif /* CONFIG_FIREWIRE_OHCI_REMOTE_DMA */
}
static u64
Index: linux/lib/Kconfig.debug
===================================================================
--- linux.orig/lib/Kconfig.debug
+++ linux/lib/Kconfig.debug
@@ -592,6 +592,16 @@ config LATENCYTOP
Enable this option if you want to use the LatencyTOP tool
to find out which userspace is blocking on what kernel operations.
+config FIREWIRE_OHCI_REMOTE_DMA
+ bool "Remote debugging via firewire-ohci"
+ depends on FIREWIRE_OHCI
+ help
+ This option lets you use the FireWire bus for remote debugging.
+ It enables unfiltered remote DMA in the firewire-ohci driver.
+ See Documentation/debugging-via-ohci1394.txt for more information.
+
+ If unsure, say N.
+
config PROVIDE_OHCI1394_DMA_INIT
bool "Provide code for enabling DMA over FireWire early on boot"
depends on PCI && X86
--
Stefan Richter
-=====-==--- -=-- -=-=-
http://arcgraph.de/sr/
--
