From: Dmitry Osipenko <digetx@gmail.com>
Date: Thu, 26 Sep 2019 22:17:55 +0300
Subject: soc/tegra: pmc: Remove unnecessary memory barrier
Git-commit: 69dfb3d4a89afccca1d8f282e49ad1362100cc43
Patch-mainline: v5.5-rc1
References: jsc#SLE-15847
The removed barrier isn't needed because writes/reads are strictly ordered
and even if PMC had separate ports for writes, it wouldn't matter since
the hardware logic takes into effect after triggering CPU's power-gating
and at that point all CPU accesses are guaranteed to be completed. That
barrier was copied from the old arch/ code during transition to the soc/
PMC driver and even that the code structure was different back then, the
barrier didn't have a real useful purpose from the start. Lastly, the
tegra_pmc_writel() naturally inserts wmb() because it uses writel(),
and thus this change doesn't actually make any difference in terms of
interacting with hardware. Hence let's remove the barrier to clean up
code a tad.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
drivers/soc/tegra/pmc.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/soc/tegra/pmc.c b/drivers/soc/tegra/pmc.c
index 1f78e8497fde..8db63cfba833 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -1478,8 +1478,6 @@ void tegra_pmc_enter_suspend_mode(enum tegra_suspend_mode mode)
do_div(ticks, USEC_PER_SEC);
tegra_pmc_writel(pmc, ticks, PMC_CPUPWROFF_TIMER);
- wmb();
-
value = tegra_pmc_readl(pmc, PMC_CNTRL);
value &= ~PMC_CNTRL_SIDE_EFFECT_LP0;
value |= PMC_CNTRL_CPU_PWRREQ_OE;
--
2.26.2