linux-kernel - [PATCH v2 1/3] clk: rockchip: rk3399: make CPU clocks critical

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Date:   Wed,  8 Sep 2021 11:13:38 -0700
From:   Brian Norris <briannorris@...omium.org>
To:     Heiko Stuebner <heiko@...ech.de>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, linux-clk@...r.kernel.org,
        Chen-Yu Tsai <wenst@...omium.org>,
        Douglas Anderson <dianders@...omium.org>,
        linux-kernel@...r.kernel.org,
        Brian Norris <briannorris@...omium.org>
Subject: [PATCH v2 1/3] clk: rockchip: rk3399: make CPU clocks critical

The CPU clocks don't currently have any owner (e.g., cpufreq-dt doesn't
enable() them -- and even if it did, it's not early enough compared to
other consumers -- nor does arch/arm64/kernel/smp.c), and instead are
simply assumed to be "on" all the time.

They are also parents of a few other clocks which haven't been
previously exposed for other devices to consume. If we want to expose
those clocks, then the common clock framework may eventually choose to
disable their parents (including the CPU PLLs) -- which is no fun for
anyone.

Thus, mark the CPU clocks as critical, to prevent them from being
disabled implicitly.

Signed-off-by: Brian Norris <briannorris@...omium.org>
---

Changes in v2:
  - New, split from the patch that requires this change

 drivers/clk/rockchip/clk-rk3399.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/rockchip/clk-rk3399.c b/drivers/clk/rockchip/clk-rk3399.c
index 62a4f2543960..0ac9c72c4ee8 100644
--- a/drivers/clk/rockchip/clk-rk3399.c
+++ b/drivers/clk/rockchip/clk-rk3399.c
@@ -1514,7 +1514,10 @@ static const char *const rk3399_cru_critical_clocks[] __initconst = {
 	"aclk_vio_noc",
 
 	/* ddrc */
-	"sclk_ddrc"
+	"sclk_ddrc",
+
+	"armclkl",
+	"armclkb",
 };
 
 static const char *const rk3399_pmucru_critical_clocks[] __initconst = {
@@ -1549,9 +1552,6 @@ static void __init rk3399_clk_init(struct device_node *np)
 	rockchip_clk_register_branches(ctx, rk3399_clk_branches,
 				  ARRAY_SIZE(rk3399_clk_branches));
 
-	rockchip_clk_protect_critical(rk3399_cru_critical_clocks,
-				      ARRAY_SIZE(rk3399_cru_critical_clocks));
-
 	rockchip_clk_register_armclk(ctx, ARMCLKL, "armclkl",
 			mux_armclkl_p, ARRAY_SIZE(mux_armclkl_p),
 			&rk3399_cpuclkl_data, rk3399_cpuclkl_rates,
@@ -1562,6 +1562,9 @@ static void __init rk3399_clk_init(struct device_node *np)
 			&rk3399_cpuclkb_data, rk3399_cpuclkb_rates,
 			ARRAY_SIZE(rk3399_cpuclkb_rates));
 
+	rockchip_clk_protect_critical(rk3399_cru_critical_clocks,
+				      ARRAY_SIZE(rk3399_cru_critical_clocks));
+
 	rockchip_register_softrst(np, 21, reg_base + RK3399_SOFTRST_CON(0),
 				  ROCKCHIP_SOFTRST_HIWORD_MASK);
 
-- 
2.33.0.153.gba50c8fa24-goog