mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-22 15:02:32 +00:00
3af779eb17
This is a backport of the patches accepted to the Linux mainline related to mvebu SoC (Armada XP and Armada 370) between Linux v3.11, and Linux v3.12. This work mainly covers: * Ground work for sharing the pxa nand driver(drivers/mtd/nand/pxa3xx_nand.c) between the PXA family,and the Armada family. * Further updates to the mvebu MBus. * Work and ground work for enabling MSI on the Armada family. * some phy / mdio bus initialization related work. * Device tree binding documentation update. Signed-off-by: Seif Mazareeb <seif.mazareeb@gmail.com> CC: Luka Perkov <luka@openwrt.org> SVN-Revision: 39565
47 lines
2.0 KiB
Diff
47 lines
2.0 KiB
Diff
From 60b78d28057f9f1ecce39955755d26e4cd3130de Mon Sep 17 00:00:00 2001
|
|
From: Lior Amsalem <alior@marvell.com>
|
|
Date: Mon, 25 Nov 2013 17:26:44 +0100
|
|
Subject: [PATCH 085/203] irqchip: armada-370-xp: fix IPI race condition
|
|
|
|
In the Armada 370/XP driver, when we receive an IRQ 0, we read the
|
|
list of doorbells that caused the interrupt from register
|
|
ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS. This gives the list of IPIs that
|
|
were generated. However, instead of acknowledging only the IPIs that
|
|
were generated, we acknowledge *all* the IPIs, by writing
|
|
~IPI_DOORBELL_MASK in the ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS register.
|
|
|
|
This creates a race condition: if a new IPI that isn't part of the
|
|
ones read into the temporary "ipimask" variable is fired before we
|
|
acknowledge all IPIs, then we will simply loose it. This is causing
|
|
scheduling hangs on SMP intensive workloads.
|
|
|
|
It is important to mention that this ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS
|
|
register has the following behavior: "A CPU write of 0 clears the bits
|
|
in this field. A CPU write of 1 has no effect". This is what allows us
|
|
to simply write ~ipimask to acknoledge the handled IPIs.
|
|
|
|
Notice that the same problem is present in the MSI implementation, but
|
|
it will be fixed as a separate patch, so that this IPI fix can be
|
|
pushed to older stable versions as appropriate (all the way to 3.8),
|
|
while the MSI code only appeared in 3.13.
|
|
|
|
Signed-off-by: Lior Amsalem <alior@marvell.com>
|
|
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
|
|
Cc: stable@vger.kernel.org
|
|
Cc: Thomas Gleixner <tglx@linutronix.de>
|
|
---
|
|
drivers/irqchip/irq-armada-370-xp.c | 2 +-
|
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
|
|
|
--- a/drivers/irqchip/irq-armada-370-xp.c
|
|
+++ b/drivers/irqchip/irq-armada-370-xp.c
|
|
@@ -407,7 +407,7 @@ armada_370_xp_handle_irq(struct pt_regs
|
|
ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS)
|
|
& IPI_DOORBELL_MASK;
|
|
|
|
- writel(~IPI_DOORBELL_MASK, per_cpu_int_base +
|
|
+ writel(~ipimask, per_cpu_int_base +
|
|
ARMADA_370_XP_IN_DRBEL_CAUSE_OFFS);
|
|
|
|
/* Handle all pending doorbells */
|