| Message ID | 87a5r7c13d.wl-kuninori.morimoto.gx@renesas.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
| Series | drivers: clk: renesas: ignore all clocks which is assinged to non Linux system | expand |
On Tue, Nov 21, 2023 at 02:05:42AM +0000, Kuninori Morimoto wrote: > Some board might use Linux and another OS in the same time. In such > case, current Linux will stop necessary module clock when booting > which is not used on Linux side, but is used on another OS side. > > To avoid such situation, renesas-cpg-mssr try to find > status = "reserved" devices (A), and add CLK_IGNORE_UNUSED flag to its > <&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@iot.bzh> > Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> > Tested-by: Yusuke Goda <yusuke.goda.sx@renesas.com> > --- > drivers/clk/renesas/renesas-cpg-mssr.c | 118 +++++++++++++++++++++++-- > 1 file changed, 109 insertions(+), 9 deletions(-) > > diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c > index cb80d1bf6c7c..26098b7f4323 100644 > --- a/drivers/clk/renesas/renesas-cpg-mssr.c > +++ b/drivers/clk/renesas/renesas-cpg-mssr.c > @@ -142,6 +142,8 @@ static const u16 srstclr_for_gen4[] = { > * @reset_clear_regs: Pointer to reset clearing registers array > * @smstpcr_saved: [].mask: Mask of SMSTPCR[] bits under our control > * [].val: Saved values of SMSTPCR[] > + * @reserved_ids: Temporary used, reserved id list > + * @num_reserved_ids: Temporary used, number of reserved id list > * @clks: Array containing all Core and Module Clocks > */ > struct cpg_mssr_priv { > @@ -168,6 +170,9 @@ struct cpg_mssr_priv { > u32 val; > } smstpcr_saved[ARRAY_SIZE(mstpsr_for_gen4)]; > > + unsigned int *reserved_ids; > + unsigned int num_reserved_ids; > + > struct clk *clks[]; > }; > > @@ -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"); 'root' is '/', so I find this slightly confusing. > + struct device_node *node = NULL; > + 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 > + * non-Linux system will be disabled when Linux was booted. > + * > + * 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 > + * to its clocks if it was CPG_MOD. > + * 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) { Don't you really want to find all reserved nodes in the DT rather than just child nodes of a single node? > + unsigned int i = 0; > + > + while (!of_parse_phandle_with_args(node, "clocks", "#clock-cells", i++, &clkspec)) { of_for_each_phandle() > + > + of_node_put(clkspec.np); > + > + if (clkspec.np == priv->dev->of_node && > + clkspec.args[0] == CPG_MOD) { > + > + 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]); > + > + num++; > + } > + } > + }
Hi Rob Thank you for reviewing the patch. > > +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"); > > 'root' is '/', so I find this slightly confusing. (snip) > > + * 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) { > > Don't you really want to find all reserved nodes in the DT rather than > just child nodes of a single node? The all devices which we need to check (and ignore the clock) in this driver is defined under /soc for now. Thank you for your help !! Best regards --- Kuninori Morimoto
Hi Morimoto-san, On Wed, Nov 29, 2023 at 12:13 AM Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> wrote: > > > +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"); > > > > 'root' is '/', so I find this slightly confusing. > (snip) > > > + * 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) { > > > > Don't you really want to find all reserved nodes in the DT rather than > > just child nodes of a single node? > > The all devices which we need to check (and ignore the clock) in this > driver is defined under /soc for now. "For now" is the right clause: all module clocks are inputs to on-SoC devices under the "soc" node. However, once the clock drivers become aware[1]* of programmable (core) clocks driving the real-time CPU cores not running Linux, you may need special handling for these, too. [1] On R-Car V3U, the clock driver already supports R8A779A0_CLK_ZR, but it is a fixed clock that cannot be disabled nor changed. Gr{oetje,eeting}s, Geert
diff --git a/drivers/clk/renesas/renesas-cpg-mssr.c b/drivers/clk/renesas/renesas-cpg-mssr.c index cb80d1bf6c7c..26098b7f4323 100644 --- a/drivers/clk/renesas/renesas-cpg-mssr.c +++ b/drivers/clk/renesas/renesas-cpg-mssr.c @@ -142,6 +142,8 @@ static const u16 srstclr_for_gen4[] = { * @reset_clear_regs: Pointer to reset clearing registers array * @smstpcr_saved: [].mask: Mask of SMSTPCR[] bits under our control * [].val: Saved values of SMSTPCR[] + * @reserved_ids: Temporary used, reserved id list + * @num_reserved_ids: Temporary used, number of reserved id list * @clks: Array containing all Core and Module Clocks */ struct cpg_mssr_priv { @@ -168,6 +170,9 @@ struct cpg_mssr_priv { u32 val; } smstpcr_saved[ARRAY_SIZE(mstpsr_for_gen4)]; + unsigned int *reserved_ids; + unsigned int num_reserved_ids; + struct clk *clks[]; }; @@ -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"); + struct device_node *node = NULL; + 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 + * non-Linux system will be disabled when Linux was booted. + * + * 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 + * to its clocks if it was CPG_MOD. + * 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)) { + + of_node_put(clkspec.np); + + if (clkspec.np == priv->dev->of_node && + clkspec.args[0] == CPG_MOD) { + + 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]); + + num++; + } + } + } + + priv->num_reserved_ids = num; + priv->reserved_ids = ids; + + return 0; +} + +static void __init cpg_mssr_common_exit(struct cpg_mssr_priv *priv) +{ + if (priv->base) + iounmap(priv->base); + kfree(priv); +} + static int __init cpg_mssr_common_init(struct device *dev, struct device_node *np, const struct cpg_mssr_info *info) @@ -1012,9 +1099,7 @@ static int __init cpg_mssr_common_init(struct device *dev, return 0; out_err: - if (priv->base) - iounmap(priv->base); - kfree(priv); + cpg_mssr_common_exit(priv); return error; } @@ -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; + 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); + + 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; + for (i = 0; i < info->num_core_clks; i++) cpg_mssr_register_core_clk(&info->core_clks[i], info, priv); @@ -1070,22 +1169,23 @@ static int __init cpg_mssr_probe(struct platform_device *pdev) cpg_mssr_del_clk_provider, np); if (error) - return error; + goto reserve_err; error = cpg_mssr_add_clk_domain(dev, info->core_pm_clks, info->num_core_pm_clks); if (error) - return error; + goto reserve_err; /* Reset Controller not supported for Standby Control SoCs */ if (priv->reg_layout == CLK_REG_LAYOUT_RZ_A) - return 0; + goto reserve_err; error = cpg_mssr_reset_controller_register(priv); - if (error) - return error; - return 0; +reserve_err: + cpg_mssr_reserved_exit(priv); + + return error; } static struct platform_driver cpg_mssr_driver = {
Some board might use Linux and another OS in the same time. In such case, current Linux will stop necessary module clock when booting which is not used on Linux side, but is used on another OS side. To avoid such situation, renesas-cpg-mssr try to find status = "reserved" devices (A), and add CLK_IGNORE_UNUSED flag to its <&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@iot.bzh> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Tested-by: Yusuke Goda <yusuke.goda.sx@renesas.com> --- drivers/clk/renesas/renesas-cpg-mssr.c | 118 +++++++++++++++++++++++-- 1 file changed, 109 insertions(+), 9 deletions(-)