linux-kernel - [PATCH 3/3] clk: meson: clk-pll: always enable a critical PLL when setting the rate

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Message-Id: <20190919093809.21364-1-narmstrong@baylibre.com>
Date:   Thu, 19 Sep 2019 11:38:09 +0200
From:   Neil Armstrong <narmstrong@...libre.com>
To:     jbrunet@...libre.com
Cc:     Neil Armstrong <narmstrong@...libre.com>,
        linux-clk@...r.kernel.org, linux-amlogic@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] clk: meson: clk-pll: always enable a critical PLL when setting the rate

Make sure we always enable a PLL on a set_rate() when the PLL is
flagged as critical.

This fixes the case when the Amlogic G12A SYS_PLL gets disabled by the
PSCI firmware when resuming from suspend-to-memory, in the case
where the CPU was not clocked by the SYS_PLL, but by the fixed PLL
fixed divisors.
In this particular case, when changing the PLL rate, CCF doesn't handle
the fact the PLL could have been disabled in the meantime and set_rate()
only changes the rate and never enables it again.

Fixes: d6e81845b7d9 ("clk: meson: clk-pll: check if the clock is already enabled')
Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/clk/meson/clk-pll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
index ddb1e5634739..8c5adccb7959 100644
--- a/drivers/clk/meson/clk-pll.c
+++ b/drivers/clk/meson/clk-pll.c
@@ -379,7 +379,7 @@ static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 	}

 	/* If the pll is stopped, bail out now */
-	if (!enabled)
+	if (!(hw->init->flags & CLK_IS_CRITICAL) && !enabled)
 		return 0;

 	if (meson_clk_pll_enable(hw)) {
-- 
2.22.0