diff mbox series

[v4,03/16] PM / devfreq: tegra: Replace write memory barrier with the read barrier

Message ID 20190501233815.32643-4-digetx@gmail.com (mailing list archive)
State Not Applicable, archived
Headers show
Series NVIDIA Tegra devfreq improvements and Tegra20/30 support | expand

Commit Message

Dmitry Osipenko May 1, 2019, 11:38 p.m. UTC 
The write memory barrier isn't needed because the BUS buffer is flushed
by read after write that happens after the removed wmb(), we will also
use readl() instead of the relaxed version to ensure that read is indeed
completed.

Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/devfreq/tegra-devfreq.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Thierry Reding June 4, 2019, 10:56 a.m. UTC | #1 
On Thu, May 02, 2019 at 02:38:02AM +0300, Dmitry Osipenko wrote:
> The write memory barrier isn't needed because the BUS buffer is flushed
> by read after write that happens after the removed wmb(), we will also
> use readl() instead of the relaxed version to ensure that read is indeed
> completed.
> 
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
>  drivers/devfreq/tegra-devfreq.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Acked-by: Thierry Reding <treding@nvidia.com>
diff mbox series

Patch

diff --git a/drivers/devfreq/tegra-devfreq.c b/drivers/devfreq/tegra-devfreq.c
index f7378a42d184..7d7b9a5895b2 100644
--- a/drivers/devfreq/tegra-devfreq.c
+++ b/drivers/devfreq/tegra-devfreq.c
@@ -243,8 +243,7 @@  static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
 static void actmon_write_barrier(struct tegra_devfreq *tegra)
 {
 	/* ensure the update has reached the ACTMON */
-	wmb();
-	actmon_readl(tegra, ACTMON_GLB_STATUS);
+	readl(tegra->regs + ACTMON_GLB_STATUS);
 }
 
 static void actmon_isr_device(struct tegra_devfreq *tegra,