[PATCH 5.4 053/177] EDAC/altera: Use fast register IO for S10 IRQs

[Greg Kroah-Hartman]

From: Meng Li <Meng.Li@xxxxxxxxxxxxx>

commit 56d9e7bd3fa0f105b6670021d167744bc50ae4fe upstream.

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@xxxxxxxxxxxxx>
Signed-off-by: Meng Li <Meng.Li@xxxxxxxxxxxxx>
Signed-off-by: Thor Thayer <thor.thayer@xxxxxxxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: linux-edac <linux-edac@xxxxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Robert Richter <rrichter@xxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Link: https://lkml.kernel.org/r/1574361048-17572-2-git-send-email-thor.thayer@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/edac/altera_edac.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -560,6 +560,7 @@ static const struct regmap_config s10_sd
 	.reg_write = s10_protected_reg_write,
 	.use_single_read = true,
 	.use_single_write = true,
+	.fast_io = true,
 };
 
 /************** </Stratix10 EDAC Memory Controller Functions> ***********/