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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jonathan Hunter <jonathanh@nvidia.com>,
        Stephen Warren <swarren@nvidia.com>,
        Thierry Reding <treding@nvidia.com>
Subject: [PATCH 4.9 057/116] clk: tegra: Mark fuse clock as critical
Date:   Thu, 13 Feb 2020 07:20:01 -0800
Message-Id: <20200213151905.073987382@linuxfoundation.org>
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From: Stephen Warren <swarren@nvidia.com>

commit bf83b96f87ae2abb1e535306ea53608e8de5dfbb upstream.

For a little over a year, U-Boot on Tegra124 has configured the flow
controller to perform automatic RAM re-repair on off->on power
transitions of the CPU rail[1]. This is mandatory for correct operation
of Tegra124. However, RAM re-repair relies on certain clocks, which the
kernel must enable and leave running. The fuse clock is one of those
clocks. Mark this clock as critical so that LP1 power mode (system
suspend) operates correctly.

[1] 3cc7942a4ae5 ARM: tegra: implement RAM repair

Reported-by: Jonathan Hunter <jonathanh@nvidia.com>
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/clk/tegra/clk-tegra-periph.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/clk/tegra/clk-tegra-periph.c
+++ b/drivers/clk/tegra/clk-tegra-periph.c
@@ -797,7 +797,11 @@ static struct tegra_periph_init_data gat
 	GATE("vcp", "clk_m", 29, 0, tegra_clk_vcp, 0),
 	GATE("apbdma", "clk_m", 34, 0, tegra_clk_apbdma, 0),
 	GATE("kbc", "clk_32k", 36, TEGRA_PERIPH_ON_APB | TEGRA_PERIPH_NO_RESET, tegra_clk_kbc, 0),
-	GATE("fuse", "clk_m", 39, TEGRA_PERIPH_ON_APB, tegra_clk_fuse, 0),
+	/*
+	 * Critical for RAM re-repair operation, which must occur on resume
+	 * from LP1 system suspend and as part of CCPLEX cluster switching.
+	 */
+	GATE("fuse", "clk_m", 39, TEGRA_PERIPH_ON_APB, tegra_clk_fuse, CLK_IS_CRITICAL),
 	GATE("fuse_burn", "clk_m", 39, TEGRA_PERIPH_ON_APB, tegra_clk_fuse_burn, 0),
 	GATE("kfuse", "clk_m", 40, TEGRA_PERIPH_ON_APB, tegra_clk_kfuse, 0),
 	GATE("apbif", "clk_m", 107, TEGRA_PERIPH_ON_APB, tegra_clk_apbif, 0),