MVNETA irq with backport-3.8

[gregory.clement@free-electrons.com (Gregory CLEMENT)]

Hi Willy,

On 05/07/2013 11:42 PM, Willy Tarreau wrote:
> Hi Gr?gory,
> 
> On Tue, May 07, 2013 at 11:27:48PM +0200, Gregory CLEMENT wrote:
>> I built and tested backport-3.8 and indeed the Ethernet is broken.
>> It was cause by a recent batch of fixes that I added, now I have to
>> figure out why they have broken the ethernet whereas they were supposed
>> to make it work better!
> 
> If that can help you, here is the list of (possibly relevant) patches
> I have applied on top of 3.9 picked from your repository some time
> ago (it's not up to date with the latest versions due to merge issues
> inducing laziness on my side) :
> 
> $ git log --oneline --grep=free-electrons v3.9.. 
> 65d2b5c ARM: mvebu: Add Device Bus and CFI flash memory support to defconfig
> 26cabde ARM: mvebu: Add support for NOR flash device on Openblocks AX3 board
> 34b32e8 ARM: mvebu: Add support for NOR flash device on Armada XP-GP board
> 31504c0 ARM: mvebu: Add Device Bus support for Armada 370/XP SoC
> 8cc752e drivers: memory: Introduce Marvell EBU Device Bus driver
> 48c6ddc arm: mvebu: update defconfig with PCI and USB support
> f4ed5ba arm: mvebu: PCIe Device Tree informations for Armada XP GP
> b1ed2c5 arm: mvebu: PCIe Device Tree informations for Armada 370 DB
> 51e91a9 arm: mvebu: PCIe Device Tree informations for Armada 370 Mirabox
> 402f9ba arm: mvebu: PCIe Device Tree informations for Armada XP DB
> 4899409 arm: mvebu: PCIe Device Tree informations for OpenBlocks AX3-4
> fb6d69f arm: mvebu: add PCIe Device Tree informations for Armada XP
> c523287 arm: mvebu: add PCIe Device Tree informations for Armada 370
> 998ee7a arm: mvebu: PCIe support is now available on mvebu
> fc9b219 pci: PCIe driver for Marvell Armada 370/XP systems
> 4b765fb clk: mvebu: add more PCIe clocks for Armada XP
> af3bcd9 clk: mvebu: create parent-child relation for PCIe clocks on Armada 370
> 6cee09e arm: pci: add a align_resource hook
> 80fa698 pci: infrastructure to add drivers in drivers/pci/host
> 91ca5a7 of/pci: Provide support for parsing PCI DT ranges property
> e46b3e7 arm: plat-orion: remove addr-map code
> d11befe arm: mach-mv78xx0: convert to use the mvebu-mbus driver
> a508a65 arm: mach-orion5x: convert to use mvebu-mbus driver
> e249639 arm: mach-dove: convert to use mvebu-mbus driver
> 70efe5e arm: mach-kirkwood: convert to use mvebu-mbus driver
> 37e82515 arm: mach-mvebu: convert to use mvebu-mbus driver
> 035f910 bus: introduce an Marvell EBU MBus driver
> 527d658 arm: mach-orion5x: use mv_mbus_dram_info() in PCI code
> c1b44db arm: plat-orion: use mv_mbus_dram_info() in PCIe code
> 59463f4 arm: plat-orion: only build addr-map.c when needed
> 
> With those my AX3 works fine. If that can help, I can send them all to
> you off-list, in case you notice a minor difference with something.

Thanks for your help but I finally found the guilty commit, it was
"66d0539 net: mvneta: convert to percpu interrupt".

This commit was never submitted because finally I realized that it was
broken in SMP. Finally it was the commit "arm: mvebu: Use local
interrupt only for the timer 0" which was the correct solution.

With the first patch I had converted the mvneta driver to use percpu
IRQ, but as I explained in the log of the 2nd patch: "the interrupts
have to be freed when the .stop() function is called. As the
free_percpu_irq() function don't disable the interrupt line, we have
to do it on each CPU before calling this. The function
disable_percpu_irq() only disable the percpu on the current CPU and
there is no function which allows to disable a percpu irq on a given
CPU."

So Greg, the solution is just to revert the commit 66d0539. I am going
to update the backport-3.8 branch in a couple of minutes.

Regards,
-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com