On 03/03/2021 09:11:57+0100, Steen Hegelund wrote: > The Sparx5 Switch SoC has a number of components that can be reset > indiviually, but at least the Switch Core needs to be in a well defined > state at power on, when any of the Sparx5 drivers starts to access the > Switch Core, this reset driver is available. > > The reset driver is loaded early via the postcore_initcall interface, and > will then be available for the other Sparx5 drivers (SGPIO, SwitchDev etc) > that are loaded next, and the first of them to be loaded can perform the > one-time Switch Core reset that is needed. > > The driver has protection so that the system busses, DDR controller, PCI-E > and ARM A53 CPU and a few other subsystems are not touched by the reset. > > Signed-off-by: Steen Hegelund <steen.hegel...@microchip.com> Reviewed-by: Alexandre Belloni <alexandre.bell...@bootlin.com>
> --- > drivers/reset/Kconfig | 8 ++ > drivers/reset/Makefile | 1 + > drivers/reset/reset-microchip-sparx5.c | 146 +++++++++++++++++++++++++ > 3 files changed, 155 insertions(+) > create mode 100644 drivers/reset/reset-microchip-sparx5.c > > diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig > index 4171c6f76385..c26798092ccf 100644 > --- a/drivers/reset/Kconfig > +++ b/drivers/reset/Kconfig > @@ -111,6 +111,14 @@ config RESET_LPC18XX > help > This enables the reset controller driver for NXP LPC18xx/43xx SoCs. > > +config RESET_MCHP_SPARX5 > + bool "Microchip Sparx5 reset driver" > + depends on HAS_IOMEM || COMPILE_TEST > + default y if SPARX5_SWITCH > + select MFD_SYSCON > + help > + This driver supports switch core reset for the Microchip Sparx5 SoC. > + > config RESET_MESON > tristate "Meson Reset Driver" > depends on ARCH_MESON || COMPILE_TEST > diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile > index 65a118a91b27..c1d6aa9b1b52 100644 > --- a/drivers/reset/Makefile > +++ b/drivers/reset/Makefile > @@ -16,6 +16,7 @@ obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o > obj-$(CONFIG_RESET_K210) += reset-k210.o > obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o > obj-$(CONFIG_RESET_LPC18XX) += reset-lpc18xx.o > +obj-$(CONFIG_RESET_MCHP_SPARX5) += reset-microchip-sparx5.o > obj-$(CONFIG_RESET_MESON) += reset-meson.o > obj-$(CONFIG_RESET_MESON_AUDIO_ARB) += reset-meson-audio-arb.o > obj-$(CONFIG_RESET_NPCM) += reset-npcm.o > diff --git a/drivers/reset/reset-microchip-sparx5.c > b/drivers/reset/reset-microchip-sparx5.c > new file mode 100644 > index 000000000000..cff39a643a14 > --- /dev/null > +++ b/drivers/reset/reset-microchip-sparx5.c > @@ -0,0 +1,146 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* Microchip Sparx5 Switch Reset driver > + * > + * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries. > + * > + * The Sparx5 Chip Register Model can be browsed at this location: > + * https://github.com/microchip-ung/sparx-5_reginfo > + */ > +#include <linux/mfd/syscon.h> > +#include <linux/of_device.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/regmap.h> > +#include <linux/reset-controller.h> > + > +#define PROTECT_REG 0x84 > +#define PROTECT_BIT BIT(10) > +#define SOFT_RESET_REG 0x00 > +#define SOFT_RESET_BIT BIT(1) > + > +struct mchp_reset_context { > + struct regmap *cpu_ctrl; > + struct regmap *gcb_ctrl; > + struct reset_controller_dev rcdev; > +}; > + > +static struct regmap_config sparx5_reset_regmap_config = { > + .reg_bits = 32, > + .val_bits = 32, > + .reg_stride = 4, > +}; > + > +static int sparx5_switch_reset(struct reset_controller_dev *rcdev, > + unsigned long id) > +{ > + struct mchp_reset_context *ctx = > + container_of(rcdev, struct mchp_reset_context, rcdev); > + u32 val; > + > + /* Make sure the core is PROTECTED from reset */ > + regmap_update_bits(ctx->cpu_ctrl, PROTECT_REG, PROTECT_BIT, > PROTECT_BIT); > + > + /* Start soft reset */ > + regmap_write(ctx->gcb_ctrl, SOFT_RESET_REG, SOFT_RESET_BIT); > + > + /* Wait for soft reset done */ > + return regmap_read_poll_timeout(ctx->gcb_ctrl, SOFT_RESET_REG, val, > + (val & SOFT_RESET_BIT) == 0, > + 1, 100); > +} > + > +static const struct reset_control_ops sparx5_reset_ops = { > + .reset = sparx5_switch_reset, > +}; > + > +static int mchp_sparx5_map_syscon(struct platform_device *pdev, char *name, > + struct regmap **target) > +{ > + struct device_node *syscon_np; > + struct regmap *regmap; > + int err; > + > + syscon_np = of_parse_phandle(pdev->dev.of_node, name, 0); > + if (!syscon_np) > + return -ENODEV; > + regmap = syscon_node_to_regmap(syscon_np); > + of_node_put(syscon_np); > + if (IS_ERR(regmap)) { > + err = PTR_ERR(regmap); > + dev_err(&pdev->dev, "No '%s' map: %d\n", name, err); > + return err; > + } > + *target = regmap; > + return 0; > +} > + > +static int mchp_sparx5_map_io(struct platform_device *pdev, int index, > + struct regmap **target) > +{ > + struct resource *res; > + struct regmap *map; > + void __iomem *mem; > + > + mem = devm_platform_get_and_ioremap_resource(pdev, index, &res); > + if (!mem) { > + dev_err(&pdev->dev, "Could not map resource %d\n", index); > + return -ENXIO; > + } > + sparx5_reset_regmap_config.name = res->name; > + map = devm_regmap_init_mmio(&pdev->dev, mem, > &sparx5_reset_regmap_config); > + if (IS_ERR(map)) > + return PTR_ERR(map); > + *target = map; > + return 0; > +} > + > +static int mchp_sparx5_reset_probe(struct platform_device *pdev) > +{ > + struct device_node *dn = pdev->dev.of_node; > + struct mchp_reset_context *ctx; > + int err; > + > + ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL); > + if (!ctx) > + return -ENOMEM; > + > + err = mchp_sparx5_map_syscon(pdev, "cpu-syscon", &ctx->cpu_ctrl); > + if (err) > + return err; > + err = mchp_sparx5_map_io(pdev, 0, &ctx->gcb_ctrl); > + if (err) > + return err; > + > + ctx->rcdev.owner = THIS_MODULE; > + ctx->rcdev.nr_resets = 1; > + ctx->rcdev.ops = &sparx5_reset_ops; > + ctx->rcdev.of_node = dn; > + > + return devm_reset_controller_register(&pdev->dev, &ctx->rcdev); > +} > + > +static const struct of_device_id mchp_sparx5_reset_of_match[] = { > + { > + .compatible = "microchip,sparx5-switch-reset", > + }, > + { } > +}; > + > +static struct platform_driver mchp_sparx5_reset_driver = { > + .probe = mchp_sparx5_reset_probe, > + .driver = { > + .name = "sparx5-switch-reset", > + .of_match_table = mchp_sparx5_reset_of_match, > + }, > +}; > + > +static int __init mchp_sparx5_reset_init(void) > +{ > + return platform_driver_register(&mchp_sparx5_reset_driver); > +} > + > +postcore_initcall(mchp_sparx5_reset_init); > + > +MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver"); > +MODULE_AUTHOR("Steen Hegelund <steen.hegel...@microchip.com>"); > +MODULE_LICENSE("Dual MIT/GPL"); > -- > 2.30.1 > -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com