Re: [PATCH 3.16 37/99] clk: tegra: Mark fuse clock as critical

[Ben Hutchings]

On Wed, 2020-05-20 at 15:14 +0100, Ben Hutchings wrote:
> 3.16.84-rc1 review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Stephen Warren <swarren@xxxxxxxxxx>
> 
> commit bf83b96f87ae2abb1e535306ea53608e8de5dfbb upstream.

I've now dropped this, as CLK_IS_CRITICAL is not implemented on 3.16.

Ben.

> 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@xxxxxxxxxx>
> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
> ---
>  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
> @@ -517,7 +517,11 @@ 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),
> 
-- 
Ben Hutchings
All the simple programs have been written, and all the good names taken

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