Dear Marek,
I have a question. I agree some clocks should be always on with CLK_IS_CRITICAL.
CLK_ACLK333 is only used on exynos5420.dtsi. So, I understand to add
CLK_IS_CRITICAL flag to CLK_ACLK333.
Except for CLK_ACLK333, the remaining clocks with CLK_IS_CRITICAL were
not used on mainline kernel (arch/arm/boot/dts/*). It means that the
remaining clocks might be ON before applying this patch. So,
CLK_IGNORE_UNUSED might be enough to maintain their ON state.
If we don't add the CLK_IGNORE_UNUSED flag to clocks except for
CLK_ACLK333, are there any problem?
But, if bootloader don't turn on these clocks, this patch is necessary.
Best Regards,
Chanwoo Choi
2016-12-22 18:44 GMT+09:00 Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>:
> Some parent clocks of the Exynos542x clock blocks, which have separate
> power domains (like DISP, MFC, MSC, GSC, FSYS and G2D) must be always
> enabled to access any register related to power management unit or devices
> connected to it. For the time being, until a proper solution based on
> runtime PM is applied, mark those clocks as critical (instead of ignore
> unused or even no flags) to prevent disabling them.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> ---
> drivers/clk/samsung/clk-exynos5420.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/clk/samsung/clk-exynos5420.c b/drivers/clk/samsung/clk-exynos5420.c
> index 8c8b495cbf0d..cdc092a1d9ef 100644
> --- a/drivers/clk/samsung/clk-exynos5420.c
> +++ b/drivers/clk/samsung/clk-exynos5420.c
> @@ -586,7 +586,7 @@ static void __init exynos5420_clk_sleep_init(void) {}
> GATE(CLK_ACLK550_CAM, "aclk550_cam", "mout_user_aclk550_cam",
> GATE_BUS_TOP, 24, 0, 0),
> GATE(CLK_ACLK432_SCALER, "aclk432_scaler", "mout_user_aclk432_scaler",
> - GATE_BUS_TOP, 27, 0, 0),
> + GATE_BUS_TOP, 27, CLK_IS_CRITICAL, 0),
> };
>
> static const struct samsung_mux_clock exynos5420_mux_clks[] __initconst = {
> @@ -956,20 +956,20 @@ static void __init exynos5420_clk_sleep_init(void) {}
> GATE(CLK_SMMU_G2D, "smmu_g2d", "aclk333_g2d", GATE_IP_G2D, 7, 0, 0),
>
> GATE(0, "aclk200_fsys", "mout_user_aclk200_fsys",
> - GATE_BUS_FSYS0, 9, CLK_IGNORE_UNUSED, 0),
> + GATE_BUS_FSYS0, 9, CLK_IS_CRITICAL, 0),
> GATE(0, "aclk200_fsys2", "mout_user_aclk200_fsys2",
> GATE_BUS_FSYS0, 10, CLK_IGNORE_UNUSED, 0),
>
> GATE(0, "aclk333_g2d", "mout_user_aclk333_g2d",
> GATE_BUS_TOP, 0, CLK_IGNORE_UNUSED, 0),
> GATE(0, "aclk266_g2d", "mout_user_aclk266_g2d",
> - GATE_BUS_TOP, 1, CLK_IGNORE_UNUSED, 0),
> + GATE_BUS_TOP, 1, CLK_IS_CRITICAL, 0),
> GATE(0, "aclk300_jpeg", "mout_user_aclk300_jpeg",
> GATE_BUS_TOP, 4, CLK_IGNORE_UNUSED, 0),
> GATE(0, "aclk333_432_isp0", "mout_user_aclk333_432_isp0",
> GATE_BUS_TOP, 5, 0, 0),
> GATE(0, "aclk300_gscl", "mout_user_aclk300_gscl",
> - GATE_BUS_TOP, 6, CLK_IGNORE_UNUSED, 0),
> + GATE_BUS_TOP, 6, CLK_IS_CRITICAL, 0),
> GATE(0, "aclk333_432_gscl", "mout_user_aclk333_432_gscl",
> GATE_BUS_TOP, 7, CLK_IGNORE_UNUSED, 0),
> GATE(0, "aclk333_432_isp", "mout_user_aclk333_432_isp",
> @@ -983,20 +983,20 @@ static void __init exynos5420_clk_sleep_init(void) {}
> GATE(0, "aclk166", "mout_user_aclk166",
> GATE_BUS_TOP, 14, CLK_IGNORE_UNUSED, 0),
> GATE(CLK_ACLK333, "aclk333", "mout_user_aclk333",
> - GATE_BUS_TOP, 15, CLK_IGNORE_UNUSED, 0),
> + GATE_BUS_TOP, 15, CLK_IS_CRITICAL, 0),
> GATE(0, "aclk400_isp", "mout_user_aclk400_isp",
> GATE_BUS_TOP, 16, 0, 0),
> GATE(0, "aclk400_mscl", "mout_user_aclk400_mscl",
> GATE_BUS_TOP, 17, 0, 0),
> GATE(0, "aclk200_disp1", "mout_user_aclk200_disp1",
> - GATE_BUS_TOP, 18, 0, 0),
> + GATE_BUS_TOP, 18, CLK_IS_CRITICAL, 0),
> GATE(CLK_SCLK_MPHY_IXTAL24, "sclk_mphy_ixtal24", "mphy_refclk_ixtal24",
> GATE_BUS_TOP, 28, 0, 0),
> GATE(CLK_SCLK_HSIC_12M, "sclk_hsic_12m", "ff_hsic_12m",
> GATE_BUS_TOP, 29, 0, 0),
>
> GATE(0, "aclk300_disp1", "mout_user_aclk300_disp1",
> - SRC_MASK_TOP2, 24, 0, 0),
> + SRC_MASK_TOP2, 24, CLK_IS_CRITICAL, 0),
>
> GATE(CLK_MAU_EPLL, "mau_epll", "mout_mau_epll_clk",
> SRC_MASK_TOP7, 20, 0, 0),
> --
> 1.9.1
>
> --
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