diff mbox series

ASoC: fsl_sai: mark regmap as fast_io

Message ID 20190717105156.15721-1-l.stach@pengutronix.de (mailing list archive)
State Accepted
Commit 6d19d8a3cec74a9680947ecb6abdeda38583110e
Headers show
Series ASoC: fsl_sai: mark regmap as fast_io | expand

Commit Message

Lucas Stach July 17, 2019, 10:51 a.m. UTC
The regmap is only ever used to access MMIO registers, so it's fair
to say that register access is fast.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
 sound/soc/fsl/fsl_sai.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Mark Brown July 17, 2019, 11:06 a.m. UTC | #1
On Wed, Jul 17, 2019 at 12:51:56PM +0200, Lucas Stach wrote:

> The regmap is only ever used to access MMIO registers, so it's fair
> to say that register access is fast.

Are you sure there's no caches that try to do allocations at
runtime?  The main thing fast_io does is change the locking to
spinlocks which means we shouldn't do any allocations under lock,
such as when updating the cache.
Lucas Stach July 17, 2019, 11:44 a.m. UTC | #2
Am Mittwoch, den 17.07.2019, 12:06 +0100 schrieb Mark Brown:
> On Wed, Jul 17, 2019 at 12:51:56PM +0200, Lucas Stach wrote:
> 
> > The regmap is only ever used to access MMIO registers, so it's fair
> > to say that register access is fast.
> 
> Are you sure there's no caches that try to do allocations at
> runtime?  The main thing fast_io does is change the locking to
> spinlocks which means we shouldn't do any allocations under lock,
> such as when updating the cache.

This driver is using REGCACHE_FLAT, which does its sole allocation on
init and none at reg access time AFAICS. So this should be okay.

Regards,
Lucas
diff mbox series

Patch

diff --git a/sound/soc/fsl/fsl_sai.c b/sound/soc/fsl/fsl_sai.c
index 8593269156bd..812c94fbb160 100644
--- a/sound/soc/fsl/fsl_sai.c
+++ b/sound/soc/fsl/fsl_sai.c
@@ -771,6 +771,7 @@  static const struct regmap_config fsl_sai_regmap_config = {
 	.reg_bits = 32,
 	.reg_stride = 4,
 	.val_bits = 32,
+	.fast_io = true,
 
 	.max_register = FSL_SAI_RMR,
 	.reg_defaults = fsl_sai_reg_defaults,