Hi Morimoto-san, Thanks for the update! s/is assigned/are assigned/ s/non Linux/non-Linux/ On Thu, Nov 30, 2023 at 3:15 AM Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> wrote: > Some board might use Linux and another OS in the same time. In such boards ... at the same > case, current Linux will stop necessary module clock when booting > which is not used on Linux side, but is used on another OS side. ... currently, during booting, Linux will stop necessary module clocks which are not used on the Linux side, but are used by another OS. > To avoid such situation, renesas-cpg-mssr try to find tries > status = "reserved" devices (A), and add CLK_IGNORE_UNUSED flag to its adds > <&cgp CPG_MOD xxx> clock (B). > > Table 2.4: Values for status property > https://github.com/devicetree-org/devicetree-specification/releases/download/v0.4/devicetree-specification-v0.4.pdf > > "reserved" > Indicates that the device is operational, but should not be > used. Typically this is used for devices that are controlled > by another software component, such as platform firmware. > > ex) > scif5: serial@e6f30000 { > ... > (B) clocks = <&cpg CPG_MOD 202>, > <&cpg CPG_CORE R8A7795_CLK_S3D1>, > <&scif_clk>; > ... > (A) status = "reserved"; > }; > > Cc: Aymeric Aillet <aymeric.aillet@xxxxxxx> > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> > Tested-by: Yusuke Goda <yusuke.goda.sx@xxxxxxxxxxx> > --- a/drivers/clk/renesas/renesas-cpg-mssr.c > +++ b/drivers/clk/renesas/renesas-cpg-mssr.c @@ -453,6 +458,19 @@ static void __init cpg_mssr_register_mod_clk(const struct mssr_mod_clk *mod, > break; > } > > + /* > + * Ignore reserved device. > + * see > + * cpg_mssr_reserved_init() > + */ > + for (i = 0; i < priv->num_reserved_ids; i++) { > + if (id == priv->reserved_ids[i]) { > + dev_info(dev, "Ignore Linux non-assigned mod (%s)\n", mod->name); > + init.flags |= CLK_IGNORE_UNUSED; > + break; > + } > + } > + > clk = clk_register(NULL, &clock->hw); > if (IS_ERR(clk)) > goto fail; > @@ -949,6 +967,75 @@ static const struct dev_pm_ops cpg_mssr_pm = { > #define DEV_PM_OPS NULL > #endif /* CONFIG_PM_SLEEP && CONFIG_ARM_PSCI_FW */ > > +static void __init cpg_mssr_reserved_exit(struct cpg_mssr_priv *priv) > +{ > + kfree(priv->reserved_ids); > +} > + > +static int __init cpg_mssr_reserved_init(struct cpg_mssr_priv *priv, > + const struct cpg_mssr_info *info) > +{ > + struct device_node *root = of_find_node_by_path("/soc"); s/root/soc/ > + struct device_node *node = NULL; No need to initialize node. > + struct of_phandle_args clkspec; > + unsigned int *ids = NULL; > + unsigned int num = 0; > + > + /* > + * Because cpg_mssr_info has .num_hw_mod_clks which indicates number of all Module Clocks, > + * and clk_disable_unused() will disable all unused clocks, the device which is assigned to "Because clk_disable_unused() will disable all unused clocks, ..."? > + * non-Linux system will be disabled when Linux was booted. a non-Linux s/was/is/ > + * > + * To avoid such situation, renesas-cpg-mssr assumes the device which has > + * status = "reserved" is assigned to non-Linux system, and add CLK_IGNORE_UNUSED flag a non-Linux ... adds > + * to its clocks if it was CPG_MOD. to its CPG_MOD clocks > + * see also > + * cpg_mssr_register_mod_clk() > + * > + * scif5: serial@e6f30000 { > + * ... > + * => clocks = <&cpg CPG_MOD 202>, > + * <&cpg CPG_CORE R8A7795_CLK_S3D1>, > + * <&scif_clk>; > + * ... > + * status = "reserved"; > + * }; > + */ > + for_each_reserved_child_of_node(root, node) { > + unsigned int i = 0; > + > + while (!of_parse_phandle_with_args(node, "clocks", "#clock-cells", i++, &clkspec)) { Looks like you missed Rob's comment on v2 to use of_for_each_phandle() instead? > + Please drop this blank line. > + of_node_put(clkspec.np); > + > + if (clkspec.np == priv->dev->of_node && > + clkspec.args[0] == CPG_MOD) { > + Please drop this blank line. > + ids = krealloc_array(ids, (num + 1), sizeof(*ids), GFP_KERNEL); > + if (!ids) > + return -ENOMEM; > + > + ids[num] = info->num_total_core_clks + > + MOD_CLK_PACK(clkspec.args[1]); This should use MOD_CLK_PACK_10() in case priv->reg_layout == CLK_REG_LAYOUT_RZ_A. > + > + num++; > + } > + } > + } > + > + priv->num_reserved_ids = num; > + priv->reserved_ids = ids; > + > + return 0; > +} > @@ -1029,6 +1114,10 @@ void __init cpg_mssr_early_init(struct device_node *np, > if (error) > return; > > + error = cpg_mssr_reserved_init(cpg_mssr_priv, info); > + if (error) > + goto err; Please move this into cpg_mssr_common_init(), which is called above. After that, there is no longer a need to factor out cpg_mssr_common_exit(). > + > for (i = 0; i < info->num_early_core_clks; i++) > cpg_mssr_register_core_clk(&info->early_core_clks[i], info, > cpg_mssr_priv); > @@ -1037,6 +1126,12 @@ void __init cpg_mssr_early_init(struct device_node *np, > cpg_mssr_register_mod_clk(&info->early_mod_clks[i], info, > cpg_mssr_priv); > > + cpg_mssr_reserved_exit(cpg_mssr_priv); Please drop this, as you still need this data when cpg_mssr_probe() is called later (yes, when a driver uses cpg_mssr_early_init(), cpg_mssr_probe() is still called later to register the non-early clocks). > + > + return; > + > +err: > + cpg_mssr_common_exit(cpg_mssr_priv); > } > > static int __init cpg_mssr_probe(struct platform_device *pdev) > @@ -1060,6 +1155,10 @@ static int __init cpg_mssr_probe(struct platform_device *pdev) > priv->dev = dev; > dev_set_drvdata(dev, priv); > > + error = cpg_mssr_reserved_init(priv, info); > + if (error) > + return error; When a driver uses cpg_mssr_early_init(), this causes the reserved clock list to be created a second time. Moving this handling into cpg_mssr_common_init() would fix that. > + > for (i = 0; i < info->num_core_clks; i++) > cpg_mssr_register_core_clk(&info->core_clks[i], info, priv); > Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
