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Message-ID: <20210302154406.n4d6euiruwan4pm5@earth.universe>
Date: Tue, 2 Mar 2021 16:44:06 +0100
From: Sebastian Reichel <sre@...nel.org>
To: Geert Uytterhoeven <geert+renesas@...der.be>
Cc: Magnus Damm <magnus.damm@...il.com>,
Saravana Kannan <saravanak@...gle.com>,
linux-renesas-soc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: renesas: rmobile-sysc: Set OF_POPULATED and absorb
reset handling
Hi,
On Fri, Feb 05, 2021 at 02:33:19PM +0100, Geert Uytterhoeven wrote:
> Currently, there are two drivers binding to the R-Mobile System
> Controller (SYSC):
> - The rmobile-sysc driver registers PM domains from a core_initcall(),
> and does not use a platform driver,
> - The rmobile-reset driver registers a reset handler, and does use a
> platform driver.
>
> As fw_devlink only considers devices, it does not know that the
> rmobile-sysc driver is ready. Hence if fw_devlink is enabled, probing
> of on-chip devices that are part of the SYSC PM domain is deferred until
> the optional rmobile-reset has been bound, which may happen too late
> (for e.g. the system timer on SoCs lacking an ARM architectured or
> global timer), or not at all, leading to complete system boot failures.
>
> Fix this by:
> 1. Setting the OF_POPULATED flag for the SYSC device node after
> successful initialization.
> This will make of_link_to_phandle() ignore the SYSC device node as
> a dependency, making consumer devices probe again.
> 2. Move reset handling from its own driver into the rmobile-sysc
> driver.
> This is needed because setting OF_POPULATED prevents the
> rmobile-reset driver from binding against the same device.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
> ---
> To be queued in renesas-devel for v5.13.
Acked-by: Sebastian Reichel <sre@...nel.org>
-- Sebastian
>
> Tested on:
> - SH-Mobile AG5 (KZM-A9-GT),
> - R-Mobile APE6 (APE6-EVM),
> - R-Mobile A1 (Armadillo-800 EVA).
>
> drivers/power/reset/Kconfig | 7 ---
> drivers/power/reset/Makefile | 1 -
> drivers/power/reset/rmobile-reset.c | 88 -----------------------------
> drivers/soc/renesas/rmobile-sysc.c | 65 ++++++++++++++++++++-
> 4 files changed, 64 insertions(+), 97 deletions(-)
> delete mode 100644 drivers/power/reset/rmobile-reset.c
>
> diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
> index 1737e227b16e5136..417b112be3f660de 100644
> --- a/drivers/power/reset/Kconfig
> +++ b/drivers/power/reset/Kconfig
> @@ -251,13 +251,6 @@ config POWER_RESET_SYSCON_POWEROFF
> help
> Poweroff support for generic SYSCON mapped register poweroff.
>
> -config POWER_RESET_RMOBILE
> - tristate "Renesas R-Mobile reset driver"
> - depends on ARCH_RMOBILE || COMPILE_TEST
> - depends on HAS_IOMEM
> - help
> - Reboot support for Renesas R-Mobile and SH-Mobile SoCs.
> -
> config POWER_RESET_ZX
> tristate "ZTE SoCs reset driver"
> depends on ARCH_ZX || COMPILE_TEST
> diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
> index b4601c0a96ed26c7..77a57ca8e5300d60 100644
> --- a/drivers/power/reset/Makefile
> +++ b/drivers/power/reset/Makefile
> @@ -29,7 +29,6 @@ obj-$(CONFIG_POWER_RESET_XGENE) += xgene-reboot.o
> obj-$(CONFIG_POWER_RESET_KEYSTONE) += keystone-reset.o
> obj-$(CONFIG_POWER_RESET_SYSCON) += syscon-reboot.o
> obj-$(CONFIG_POWER_RESET_SYSCON_POWEROFF) += syscon-poweroff.o
> -obj-$(CONFIG_POWER_RESET_RMOBILE) += rmobile-reset.o
> obj-$(CONFIG_POWER_RESET_ZX) += zx-reboot.o
> obj-$(CONFIG_REBOOT_MODE) += reboot-mode.o
> obj-$(CONFIG_SYSCON_REBOOT_MODE) += syscon-reboot-mode.o
> diff --git a/drivers/power/reset/rmobile-reset.c b/drivers/power/reset/rmobile-reset.c
> deleted file mode 100644
> index bd3b396558e0df8c..0000000000000000
> --- a/drivers/power/reset/rmobile-reset.c
> +++ /dev/null
> @@ -1,88 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Renesas R-Mobile Reset Driver
> - *
> - * Copyright (C) 2014 Glider bvba
> - */
> -
> -#include <linux/io.h>
> -#include <linux/module.h>
> -#include <linux/notifier.h>
> -#include <linux/of_address.h>
> -#include <linux/platform_device.h>
> -#include <linux/printk.h>
> -#include <linux/reboot.h>
> -
> -/* SYSC Register Bank 2 */
> -#define RESCNT2 0x20 /* Reset Control Register 2 */
> -
> -/* Reset Control Register 2 */
> -#define RESCNT2_PRES 0x80000000 /* Soft power-on reset */
> -
> -static void __iomem *sysc_base2;
> -
> -static int rmobile_reset_handler(struct notifier_block *this,
> - unsigned long mode, void *cmd)
> -{
> - pr_debug("%s %lu\n", __func__, mode);
> -
> - /* Let's assume we have acquired the HPB semaphore */
> - writel(RESCNT2_PRES, sysc_base2 + RESCNT2);
> -
> - return NOTIFY_DONE;
> -}
> -
> -static struct notifier_block rmobile_reset_nb = {
> - .notifier_call = rmobile_reset_handler,
> - .priority = 192,
> -};
> -
> -static int rmobile_reset_probe(struct platform_device *pdev)
> -{
> - int error;
> -
> - sysc_base2 = of_iomap(pdev->dev.of_node, 1);
> - if (!sysc_base2)
> - return -ENODEV;
> -
> - error = register_restart_handler(&rmobile_reset_nb);
> - if (error) {
> - dev_err(&pdev->dev,
> - "cannot register restart handler (err=%d)\n", error);
> - goto fail_unmap;
> - }
> -
> - return 0;
> -
> -fail_unmap:
> - iounmap(sysc_base2);
> - return error;
> -}
> -
> -static int rmobile_reset_remove(struct platform_device *pdev)
> -{
> - unregister_restart_handler(&rmobile_reset_nb);
> - iounmap(sysc_base2);
> - return 0;
> -}
> -
> -static const struct of_device_id rmobile_reset_of_match[] = {
> - { .compatible = "renesas,sysc-rmobile", },
> - { /* sentinel */ }
> -};
> -MODULE_DEVICE_TABLE(of, rmobile_reset_of_match);
> -
> -static struct platform_driver rmobile_reset_driver = {
> - .probe = rmobile_reset_probe,
> - .remove = rmobile_reset_remove,
> - .driver = {
> - .name = "rmobile_reset",
> - .of_match_table = rmobile_reset_of_match,
> - },
> -};
> -
> -module_platform_driver(rmobile_reset_driver);
> -
> -MODULE_DESCRIPTION("Renesas R-Mobile Reset Driver");
> -MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@...der.be>");
> -MODULE_LICENSE("GPL v2");
> diff --git a/drivers/soc/renesas/rmobile-sysc.c b/drivers/soc/renesas/rmobile-sysc.c
> index bf64d052f9245db5..a8d85d111924d9ee 100644
> --- a/drivers/soc/renesas/rmobile-sysc.c
> +++ b/drivers/soc/renesas/rmobile-sysc.c
> @@ -1,10 +1,11 @@
> // SPDX-License-Identifier: GPL-2.0
> /*
> - * rmobile power management support
> + * R-Mobile power management and reset support
> *
> * Copyright (C) 2012 Renesas Solutions Corp.
> * Copyright (C) 2012 Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>
> * Copyright (C) 2014 Glider bvba
> + * Copyright (C) 2021 Glider bv
> *
> * based on pm-sh7372.c
> * Copyright (C) 2011 Magnus Damm
> @@ -12,11 +13,13 @@
> #include <linux/clk/renesas.h>
> #include <linux/console.h>
> #include <linux/delay.h>
> +#include <linux/notifier.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/pm.h>
> #include <linux/pm_clock.h>
> #include <linux/pm_domain.h>
> +#include <linux/reboot.h>
> #include <linux/slab.h>
>
> #include <asm/io.h>
> @@ -29,6 +32,11 @@
> #define PSTR_RETRIES 100
> #define PSTR_DELAY_US 10
>
> +/* SYSC Register Bank 2 */
> +#define RESCNT2 0x20 /* Reset Control Register 2 */
> +
> +#define RESCNT2_PRES BIT(31) /* Soft power-on reset */
> +
> struct rmobile_pm_domain {
> struct generic_pm_domain genpd;
> struct dev_power_governor *gov;
> @@ -309,6 +317,54 @@ static int __init rmobile_add_pm_domains(void __iomem *base,
> return 0;
> }
>
> +struct rmobile_reset {
> + void __iomem *base;
> + struct notifier_block nb;
> +};
> +
> +static int rmobile_reset_handler(struct notifier_block *this,
> + unsigned long mode, void *cmd)
> +{
> + struct rmobile_reset *reset = container_of(this, struct rmobile_reset,
> + nb);
> +
> + pr_debug("%s %lu\n", __func__, mode);
> +
> + /* Let's assume we have acquired the HPB semaphore */
> + writel(RESCNT2_PRES, reset->base + RESCNT2);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static int rmobile_reset_setup(struct device_node *np)
> +{
> + struct rmobile_reset *reset;
> + int error;
> +
> + reset = kzalloc(sizeof(*reset), GFP_KERNEL);
> + if (!reset)
> + return -ENOMEM;
> +
> + reset->base = of_iomap(np, 1);
> + if (!reset->base)
> + goto fail_free;
> +
> + reset->nb.notifier_call = rmobile_reset_handler;
> + reset->nb.priority = 192;
> +
> + error = register_restart_handler(&reset->nb);
> + if (error)
> + goto fail_unmap;
> +
> + return 0;
> +
> +fail_unmap:
> + iounmap(reset->base);
> +fail_free:
> + kfree(reset);
> + return error;
> +}
> +
> static int __init rmobile_init_pm_domains(void)
> {
> struct device_node *np, *pmd;
> @@ -342,6 +398,13 @@ static int __init rmobile_init_pm_domains(void)
> of_node_put(np);
> break;
> }
> +
> + of_node_set_flag(np, OF_POPULATED);
> +
> + ret = rmobile_reset_setup(np);
> + if (ret)
> + pr_err("%pOF: cannot register restart handler (%d)\n",
> + np, ret);
> }
>
> put_special_pds();
> --
> 2.25.1
>
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