// SPDX-License-Identifier: GPL-2.0 /* * Copyright (c) 2019 Intel Corporation. * Lei Chuanhua <Chuanhua.lei@intel.com> */ #include <linux/bitfield.h> #include <linux/init.h> #include <linux/of_device.h> #include <linux/platform_device.h> #include <linux/reboot.h> #include <linux/regmap.h> #include <linux/reset-controller.h> #define RCU_RST_STAT 0x0024 #define RCU_RST_REQ 0x0048 #define REG_OFFSET_MASK GENMASK(31, 16) #define BIT_OFFSET_MASK GENMASK(15, 8) #define STAT_BIT_OFFSET_MASK GENMASK(7, 0) #define to_reset_data(x) container_of(x, struct intel_reset_data, rcdev) struct intel_reset_soc { bool legacy; u32 reset_cell_count; }; struct intel_reset_data { struct reset_controller_dev rcdev; struct notifier_block restart_nb; const struct intel_reset_soc *soc_data; struct regmap *regmap; struct device *dev; u32 reboot_id; }; static const struct regmap_config intel_rcu_regmap_config = { .name = "intel-reset", .reg_bits = 32, .reg_stride = 4, .val_bits = 32, .fast_io = true, }; /* * Reset status register offset relative to * the reset control register(X) is X + 4 */ static u32 id_to_reg_and_bit_offsets(struct intel_reset_data *data, unsigned long id, u32 *rst_req, u32 *req_bit, u32 *stat_bit) { *rst_req = FIELD_GET(REG_OFFSET_MASK, id); *req_bit = FIELD_GET(BIT_OFFSET_MASK, id); if (data->soc_data->legacy) *stat_bit = FIELD_GET(STAT_BIT_OFFSET_MASK, id); else *stat_bit = *req_bit; if (data->soc_data->legacy && *rst_req == RCU_RST_REQ) return RCU_RST_STAT; else return *rst_req + 0x4; } static int intel_set_clr_bits(struct intel_reset_data *data, unsigned long id, bool set) { u32 rst_req, req_bit, rst_stat, stat_bit, val; int ret; rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req, &req_bit, &stat_bit); val = set ? BIT(req_bit) : 0; ret = regmap_update_bits(data->regmap, rst_req, BIT(req_bit), val); if (ret) return ret; return regmap_read_poll_timeout(data->regmap, rst_stat, val, set == !!(val & BIT(stat_bit)), 20, 200); } static int intel_assert_device(struct reset_controller_dev *rcdev, unsigned long id) { struct intel_reset_data *data = to_reset_data(rcdev); int ret; ret = intel_set_clr_bits(data, id, true); if (ret) dev_err(data->dev, "Reset assert failed %d\n", ret); return ret; } static int intel_deassert_device(struct reset_controller_dev *rcdev, unsigned long id) { struct intel_reset_data *data = to_reset_data(rcdev); int ret; ret = intel_set_clr_bits(data, id, false); if (ret) dev_err(data->dev, "Reset deassert failed %d\n", ret); return ret; } static int intel_reset_status(struct reset_controller_dev *rcdev, unsigned long id) { struct intel_reset_data *data = to_reset_data(rcdev); u32 rst_req, req_bit, rst_stat, stat_bit, val; int ret; rst_stat = id_to_reg_and_bit_offsets(data, id, &rst_req, &req_bit, &stat_bit); ret = regmap_read(data->regmap, rst_stat, &val); if (ret) return ret; return !!(val & BIT(stat_bit)); } static const struct reset_control_ops intel_reset_ops = { .assert = intel_assert_device, .deassert = intel_deassert_device, .status = intel_reset_status, }; static int intel_reset_xlate(struct reset_controller_dev *rcdev, const struct of_phandle_args *spec) { struct intel_reset_data *data = to_reset_data(rcdev); u32 id; if (spec->args[1] > 31) return -EINVAL; id = FIELD_PREP(REG_OFFSET_MASK, spec->args[0]); id |= FIELD_PREP(BIT_OFFSET_MASK, spec->args[1]); if (data->soc_data->legacy) { if (spec->args[2] > 31) return -EINVAL; id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, spec->args[2]); } return id; } static int intel_reset_restart_handler(struct notifier_block *nb, unsigned long action, void *data) { struct intel_reset_data *reset_data; reset_data = container_of(nb, struct intel_reset_data, restart_nb); intel_assert_device(&reset_data->rcdev, reset_data->reboot_id); return NOTIFY_DONE; } static int intel_reset_probe(struct platform_device *pdev) { struct device_node *np = pdev->dev.of_node; struct device *dev = &pdev->dev; struct intel_reset_data *data; void __iomem *base; u32 rb_id[3]; int ret; data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; data->soc_data = of_device_get_match_data(dev); if (!data->soc_data) return -ENODEV; base = devm_platform_ioremap_resource(pdev, 0); if (IS_ERR(base)) return PTR_ERR(base); data->regmap = devm_regmap_init_mmio(dev, base, &intel_rcu_regmap_config); if (IS_ERR(data->regmap)) { dev_err(dev, "regmap initialization failed\n"); return PTR_ERR(data->regmap); } ret = device_property_read_u32_array(dev, "intel,global-reset", rb_id, data->soc_data->reset_cell_count); if (ret) { dev_err(dev, "Failed to get global reset offset!\n"); return ret; } data->dev = dev; data->rcdev.of_node = np; data->rcdev.owner = dev->driver->owner; data->rcdev.ops = &intel_reset_ops; data->rcdev.of_xlate = intel_reset_xlate; data->rcdev.of_reset_n_cells = data->soc_data->reset_cell_count; ret = devm_reset_controller_register(&pdev->dev, &data->rcdev); if (ret) return ret; data->reboot_id = FIELD_PREP(REG_OFFSET_MASK, rb_id[0]); data->reboot_id |= FIELD_PREP(BIT_OFFSET_MASK, rb_id[1]); if (data->soc_data->legacy) data->reboot_id |= FIELD_PREP(STAT_BIT_OFFSET_MASK, rb_id[2]); data->restart_nb.notifier_call = intel_reset_restart_handler; data->restart_nb.priority = 128; register_restart_handler(&data->restart_nb); return 0; } static const struct intel_reset_soc xrx200_data = { .legacy = true, .reset_cell_count = 3, }; static const struct intel_reset_soc lgm_data = { .legacy = false, .reset_cell_count = 2, }; static const struct of_device_id intel_reset_match[] = { { .compatible = "intel,rcu-lgm", .data = &lgm_data }, { .compatible = "intel,rcu-xrx200", .data = &xrx200_data }, {} }; static struct platform_driver intel_reset_driver = { .probe = intel_reset_probe, .driver = { .name = "intel-reset", .of_match_table = intel_reset_match, }, }; static int __init intel_reset_init(void) { return platform_driver_register(&intel_reset_driver); } /* * RCU is system core entity which is in Always On Domain whose clocks * or resource initialization happens in system core initialization. * Also, it is required for most of the platform or architecture * specific devices to perform reset operation as part of initialization. * So perform RCU as post core initialization. */ postcore_initcall(intel_reset_init);