From: Meng Li <Meng.Li@windriver.com>
Date: Thu, 21 Nov 2019 12:30:46 -0600
Subject: EDAC/altera: Use fast register IO for S10 IRQs
Git-commit: 56d9e7bd3fa0f105b6670021d167744bc50ae4fe
Patch-mainline: v5.5-rc1
References: bsc#1152489 bnc#1151927 5.3.17

When an IRQ occurs, regmap_{read,write,...}() is invoked in atomic
context. Regmap must indicate register IO is fast so that a spinlock is
used instead of a mutex to avoid sleeping in atomic context:

  lock_acquire
  __mutex_lock
  mutex_lock_nested
  regmap_lock_mutex
  regmap_write
  a10_eccmgr_irq_unmask
  unmask_irq.part.0
  irq_enable
  __irq_startup
  irq_startup
  __setup_irq
  request_threaded_irq
  devm_request_threaded_irq
  altr_sdram_probe

Mark it so.

 [ bp: Massage. ]

Fixes: 3dab6bd52687 ("EDAC, altera: Add support for Stratix10 SDRAM EDAC")
Reported-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Meng Li <Meng.Li@windriver.com>
Signed-off-by: Thor Thayer <thor.thayer@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: James Morse <james.morse@arm.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Robert Richter <rrichter@marvell.com>
Cc: stable <stable@vger.kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/1574361048-17572-2-git-send-email-thor.thayer@linux.intel.com
---
 drivers/edac/altera_edac.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index fbda4b876afd..0be3d1b17f03 100644
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -560,6 +560,7 @@ static const struct regmap_config s10_sdram_regmap_cfg = {
 	.reg_write = s10_protected_reg_write,
 	.use_single_read = true,
 	.use_single_write = true,
+	.fast_io = true,
 };
 
 /************** </Stratix10 EDAC Memory Controller Functions> ***********/