From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Peter De Schrijver <pdeschrijver@nvidia.com>
Cc: linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 2/2] soc/tegra: pmc: Remove unnecessary memory barrier
Date: Tue, 23 Jul 2019 05:35:11 +0300 [thread overview]
Message-ID: <20190723023511.24542-2-digetx@gmail.com> (raw)
In-Reply-To: <20190723023511.24542-1-digetx@gmail.com>
The removed barrier isn't needed because the writes/reads are strictly
ordered and even if PMC had separate ports for the 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. Hence remove the barrier to eliminate the confusion.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
Changelog:
v2: New patch that was added after Jon's Hunter pointing that it's better
not to change the barrier's placement in the code. In fact the barrier
is not needed at all.
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 aba3396b2e73..3044809f1c10 100644
--- a/drivers/soc/tegra/pmc.c
+++ b/drivers/soc/tegra/pmc.c
@@ -1457,8 +1457,6 @@ 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;
--
2.22.0
next prev parent reply other threads:[~2019-07-23 2:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 2:35 [PATCH v2 1/2] soc/tegra: pmc: Query PCLK clock rate at probe time Dmitry Osipenko
2019-07-23 2:35 ` Dmitry Osipenko [this message]
2019-07-25 9:36 ` Peter De Schrijver
2019-07-25 11:15 ` Dmitry Osipenko
2019-07-29 13:07 ` Dmitry Osipenko
2019-07-30 17:40 ` Dmitry Osipenko
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