Re: [PATCH 08/17] clk: samsung: gs101: add support for cmu_hsi2

["André Draszik" <andre.draszik@linaro.org>]

Hi Pete,

On Thu, 2024-04-04 at 13:25 +0100, Peter Griffin wrote:
> CMU_HSI2 is the clock management unit used for the hsi2 block.
> HSI stands for High Speed Interface and as such it generates
> clocks for PCIe, UFS and MMC card.
> 
> This patch adds support for the muxes, dividers, and gates in
> cmu_hsi2.
> 
> CLK_GOUT_HSI2_HSI2_CMU_HSI2_PCLK is marked as CLK_IS_CRITICAL
> as disabling it leads to an immediate system hang.
> 
> CLK_GOUT_HSI2_SYSREG_HSI2_PCLK is also marked CLK_IS_CRITICAL.
> A hang is not observed with fine grained clock control, but
> UFS IP does not function with syscon controlling this clock
> just around hsi2_sysreg register accesses.

Would it make sense to add this clock to the &ufs_0 node in the DTS
instead? Seems more natural than a clock that's constantly enabled?

> [...]
> 
> Updated regex for clock name mangling
>     sed \
>         -e 's|^PLL_LOCKTIME_PLL_\([^_]\+\)|fout_\L\1_pll|' \
>         \
>         -e 's|^PLL_CON0_MUX_CLKCMU_\([^_]\+\)_\(.*\)|mout_\L\1_\2|' \
>         -e 's|^PLL_CON0_PLL_\(.*\)|mout_pll_\L\1|' \
>         -e 's|^CLK_CON_MUX_MUX_CLK_\(.*\)|mout_\L\1|' \
>         -e '/^PLL_CON[1-4]_[^_]\+_/d' \
>         -e '/^[^_]\+_CMU_[^_]\+_CONTROLLER_OPTION/d' \
>         -e '/^CLKOUT_CON_BLK_[^_]\+_CMU_[^_]\+_CLKOUT0/d' \
>         \
>         -e 's|_IPCLKPORT||' \
>         -e 's|_RSTNSYNC||' \
>         -e 's|_G4X2_DWC_PCIE_CTL||' \
>         -e 's|_G4X1_DWC_PCIE_CTL||' \
>         -e 's|_PCIE_SUB_CTRL||' \
>         -e 's|_INST_0||g' \
>         -e 's|_LN05LPE||' \
>         -e 's|_TM_WRAPPER||' \
>         -e 's|_SF||' \
>         \
>         -e 's|^CLK_CON_DIV_DIV_CLK_\([^_]\+\)_\(.*\)|dout_\L\1_\2|' \
>         \
>         -e 's|^CLK_CON_BUF_CLKBUF_\([^_]\+\)_\(.*\)|gout_\L\1_\2|' \
>         -e 's|^CLK_CON_GAT_CLK_BLK_\([^_]\+\)_UID_\(.*\)|gout_\L\1_\2|' \
>         -e 's|^gout_[^_]\+_[^_]\+_cmu_\([^_]\+\)_pclk$|gout_\1_\1_pclk|' \
>         -e 's|^CLK_CON_GAT_GOUT_BLK_\([^_]\+\)_UID_\(.*\)|gout_\L\1_\2|' \
>         -e 's|^CLK_CON_GAT_CLK_\([^_]\+\)_\(.*\)|gout_\L\1_clk_\L\1_\2|' \
>         \
>         -e '/^\(DMYQCH\|PCH\|QCH\|QUEUE\)_/d'

Thank you for the updated regex.

> ---
>  drivers/clk/samsung/clk-gs101.c          | 558 +++++++++++++++++++++++
>  include/dt-bindings/clock/google,gs101.h |  63 +++
>  2 files changed, 621 insertions(+)
> 
> diff --git a/drivers/clk/samsung/clk-gs101.c b/drivers/clk/samsung/clk-gs101.c
> index d065e343a85d..b9f84c7d5c22 100644
> --- a/drivers/clk/samsung/clk-gs101.c
> +++ b/drivers/clk/samsung/clk-gs101.c
> @@ -22,6 +22,7 @@
>  #define CLKS_NR_MISC	(CLK_GOUT_MISC_XIU_D_MISC_ACLK + 1)
>  #define CLKS_NR_PERIC0	(CLK_GOUT_PERIC0_SYSREG_PERIC0_PCLK + 1)
>  #define CLKS_NR_PERIC1	(CLK_GOUT_PERIC1_SYSREG_PERIC1_PCLK + 1)
> +#define CLKS_NR_HSI2	(CLK_GOUT_HSI2_XIU_P_HSI2_ACLK + 1)
>  
>  /* ---- CMU_TOP ------------------------------------------------------------- */
>  
> @@ -3409,6 +3410,560 @@ static const struct samsung_cmu_info peric1_cmu_info __initconst = {
>  	.clk_name		= "bus",
>  };
>  
> +/* ---- CMU_HSI2 ---------------------------------------------------------- */

This comment is shorter that all the other similar comments in this file.

> [...]
> +
> +PNAME(mout_hsi2_bus_user_p)	= { "oscclk", "dout_cmu_hsi2_bus" };
> +PNAME(mout_hsi2_pcie_user_p)	= { "oscclk", "dout_cmu_hsi2_pcie" };
> +PNAME(mout_hsi2_ufs_embd_user_p) = { "oscclk", "dout_cmu_hsi2_ufs_embd" };
> +PNAME(mout_hsi2_mmc_card_user_p) = { "oscclk", "dout_cmu_hsi2_mmc_card" };

Can you make these alphabetical, too, please, which would also match their usage
below:

> +
> +static const struct samsung_mux_clock hsi2_mux_clks[] __initconst = {
> +	MUX(CLK_MOUT_HSI2_BUS_USER, "mout_hsi2_bus_user", mout_hsi2_bus_user_p,
> +	    PLL_CON0_MUX_CLKCMU_HSI2_BUS_USER, 4, 1),
> +	MUX(CLK_MOUT_HSI2_MMC_CARD_USER, "mout_hsi2_mmc_card_user",
> +	    mout_hsi2_mmc_card_user_p, PLL_CON0_MUX_CLKCMU_HSI2_MMC_CARD_USER,
> +	    4, 1),
> +	MUX(CLK_MOUT_HSI2_PCIE_USER, "mout_hsi2_pcie_user",
> +	    mout_hsi2_pcie_user_p, PLL_CON0_MUX_CLKCMU_HSI2_PCIE_USER,
> +	    4, 1),
> +	MUX(CLK_MOUT_HSI2_UFS_EMBD_USER, "mout_hsi2_ufs_embd_user",
> +	    mout_hsi2_ufs_embd_user_p, PLL_CON0_MUX_CLKCMU_HSI2_UFS_EMBD_USER,
> +	    4, 1),
> +};
> +
> +static const struct samsung_gate_clock hsi2_gate_clks[] __initconst = {
> +

Here and below: all these extra empty lines are not needed.

> +	GATE(CLK_GOUT_HSI2_PCIE_GEN4_1_PCIE_003_PHY_REFCLK_IN,
> +	     "gout_hsi2_pcie_gen4_1_pcie_003_phy_refclk_in",
> +	     "mout_hsi2_pcie_user",
> +	     CLK_CON_GAT_CLK_BLK_HSI2_UID_PCIE_GEN4_1_IPCLKPORT_PCIE_003_PCIE_SUB_CTRL_INST_0_PHY_REFCLK_IN,
> +	     21, 0, 0),
> +
> +	GATE(CLK_GOUT_HSI2_PCIE_GEN4_1_PCIE_004_PHY_REFCLK_IN,
> +	     "gout_hsi2_pcie_gen4_1_pcie_004_phy_refclk_in",
> +	     "mout_hsi2_pcie_user",
> +	     CLK_CON_GAT_CLK_BLK_HSI2_UID_PCIE_GEN4_1_IPCLKPORT_PCIE_004_PCIE_SUB_CTRL_INST_0_PHY_REFCLK_IN,
> +	     21, 0, 0),
> +
> +	GATE(CLK_GOUT_HSI2_SSMT_PCIE_IA_GEN4A_1_ACLK,
> +	     "gout_hsi2_ssmt_pcie_ia_gen4a_1_aclk",
> +	     "mout_hsi2_bus_user",

The two strings fit on the same line.

> +	     CLK_CON_GAT_CLK_BLK_HSI2_UID_SSMT_PCIE_IA_GEN4A_1_IPCLKPORT_ACLK,
> +	     21, 0, 0),
> +
> +	GATE(CLK_GOUT_HSI2_SSMT_PCIE_IA_GEN4A_1_PCLK,
> +	     "gout_hsi2_ssmt_pcie_ia_gen4a_1_pclk",
> +	     "mout_hsi2_bus_user",

dito.

> [...]
> +	/* Disabling this clock makes the system hang. Mark the clock as critical. */
> +	GATE(CLK_GOUT_HSI2_HSI2_CMU_HSI2_PCLK,
> +	     "gout_hsi2_hsi2_cmu_hsi2_pclk", "mout_hsi2_bus_user",
> +	     CLK_CON_GAT_GOUT_BLK_HSI2_UID_HSI2_CMU_HSI2_IPCLKPORT_PCLK,
> +	     21, CLK_IS_CRITICAL, 0),

I have a similar clock in USB, which also causes a hang if off, I wonder what we
could do better here.


Cheers,
Andre'