[PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[Brent Cook]

This patch disable interrupts on all ports during initialization. The current 
assumes that the firmware has already disabled all interrupts on all ports. 
We have encountered some boards that do not always disable interrupts (XES 
XPedite 6200 for instance) on a soft reset. This patch prevents a kernel 
panic if a packet is received before the DMA ring buffers are setup for a 
port on which interrupts are left enabled by the firmware.

Signed-off-by: Brent Cook <bcook@bpointsys.com>

Index: linux-2.6-bps/drivers/net/mv643xx_eth.c
===================================================================
--- linux-2.6-bps/drivers/net/mv643xx_eth.c	(revision 100)
+++ linux-2.6-bps/drivers/net/mv643xx_eth.c	(revision 101)
@@ -777,6 +777,13 @@
 	unsigned int size;
 	int err;
 
+	/* Mask all interrupts on ethernet port */
+	mv_write(MV643XX_ETH_INTERRUPT_MASK_REG(port_num),
+		 ETH_INT_MASK_ALL);
+	/* wait for previous write to complete */
+	mv_read(MV643XX_ETH_INTERRUPT_MASK_REG(port_num));
+
 	err = request_irq(dev->irq, mv643xx_eth_int_handler,
 			SA_SHIRQ | SA_SAMPLE_RANDOM, dev->name, dev);
 	if (err) {

Re: [PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[John Haller]

Brent Cook wrote:
> This patch disable interrupts on all ports during initialization. The current 
> assumes that the firmware has already disabled all interrupts on all ports. 
> We have encountered some boards that do not always disable interrupts (XES 
> XPedite 6200 for instance) on a soft reset. This patch prevents a kernel 
> panic if a packet is received before the DMA ring buffers are setup for a 
> port on which interrupts are left enabled by the firmware.
You probably have bigger problems than the interrupt being left
enabled.  If the interrupt is left enabled, the DMA engine
is probably left enabled, and if a packet happens
to come in before the driver can properly configure them,
some random part of memory will get overwritten.
The firmware needs to disable this device before transferring
control to the kernel, both the interrupts and the DMA,
there is no way to fix this in the kernel.

Re: [PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[Nathaniel Case]

On Tue, 2006-06-27 at 10:16 -0500, John Haller wrote:
> Brent Cook wrote:
> > This patch disable interrupts on all ports during initialization. The current 
> > assumes that the firmware has already disabled all interrupts on all ports. 
> > We have encountered some boards that do not always disable interrupts (XES 
> > XPedite 6200 for instance) on a soft reset. This patch prevents a kernel 
> > panic if a packet is received before the DMA ring buffers are setup for a 
> > port on which interrupts are left enabled by the firmware.
> You probably have bigger problems than the interrupt being left
> enabled.  If the interrupt is left enabled, the DMA engine
> is probably left enabled, and if a packet happens
> to come in before the driver can properly configure them,
> some random part of memory will get overwritten.
> The firmware needs to disable this device before transferring
> control to the kernel, both the interrupts and the DMA,
> there is no way to fix this in the kernel.

I agree that the patch isn't the best fix for this problem.

Brent, for this particular case, I believe there's chip errata for the
Discovery bridge preventing it from resetting itself when the board
resets itself in non-monarch mode.  That's why interrupts are left
enabled.  This issue should never crop up if the board is monarch on the
PCI bus.

So the proper workaround would be for our firmware to account for this
case and disable interrupts, ethernet, etc. on a soft non-monarch reset.
We could also do this in the boot wrapper code as a safety measure.

Also, note that the firmware _will_ already explicitly disable ethernet
before transferring control over to the OS _if_ you're booting over
ethernet instead of flash.

- Nate Case <ncase@xes-inc.com>

Re: [PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[Jeff Garzik]

Brent Cook wrote:
> This patch disable interrupts on all ports during initialization. The current 
> assumes that the firmware has already disabled all interrupts on all ports. 
> We have encountered some boards that do not always disable interrupts (XES 
> XPedite 6200 for instance) on a soft reset. This patch prevents a kernel 
> panic if a packet is received before the DMA ring buffers are setup for a 
> port on which interrupts are left enabled by the firmware.
> 
> Signed-off-by: Brent Cook <bcook@bpointsys.com>

ACK patches 1-3, but:


[jgarzik@pretzel netdev-2.6]$ git-applymbox /g/tmp/mbox ~/info/signoff.txt
3 patch(es) to process.

Applying 'mv643xx fixes - Disable interrupts on all ports during 
initialization'
fatal: corrupt patch at line 19

[PATCH 1/3] mv643xx fixes - Disable interrupts on all ports during initialization

[Brent Cook]

That's the last time I hand-edit a patch - this is really more of a workaround 
since I've learned that the interrupts should have been disabled by the 
firmware anyway. But, it doesn't hurt. Updated description

This patch disable interrupts on all ports during initialization. The
current driver assumes that the firmware has already disabled all interrupts 
on all ports. We have encountered some boards that do not always disable
interrupts (XES XPedite 6200 for instance) on a soft reset on all ethernet 
ports. This patch prevents a kernel panic if a packet is received before the 
DMA ring buffers are setup for a port on which interrupts are left enabled by 
the firmware.

Signed-off-by: Brent Cook <bcook@bpointsys.com>

Index: current/drivers/net/mv643xx_eth.c
===================================================================
--- current/drivers/net/mv643xx_eth.c	(revision 101)
+++ current/drivers/net/mv643xx_eth.c	(working copy)
@@ -777,6 +777,12 @@
 	unsigned int size;
 	int err;
 
+	/* Mask all interrupts on ethernet port */
+	mv_write(MV643XX_ETH_INTERRUPT_MASK_REG(port_num),
+		ETH_INT_MASK_ALL);
+	/* wait for previous write to complete */
+	mv_read(MV643XX_ETH_INTERRUPT_MASK_REG(port_num));
+
 	err = request_irq(dev->irq, mv643xx_eth_int_handler,
 			SA_SHIRQ | SA_SAMPLE_RANDOM, dev->name, dev);
 	if (err) {