1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Broadcom STB generic reset controller for SW_INIT style reset controller 4 * 5 * Author: Florian Fainelli <f.fainelli@gmail.com> 6 * Copyright (C) 2018 Broadcom 7 */ 8 #include <linux/delay.h> 9 #include <linux/device.h> 10 #include <linux/io.h> 11 #include <linux/module.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 #include <linux/reset-controller.h> 15 #include <linux/types.h> 16 17 struct brcmstb_reset { 18 void __iomem *base; 19 struct reset_controller_dev rcdev; 20 }; 21 22 #define SW_INIT_SET 0x00 23 #define SW_INIT_CLEAR 0x04 24 #define SW_INIT_STATUS 0x08 25 26 #define SW_INIT_BIT(id) BIT((id) & 0x1f) 27 #define SW_INIT_BANK(id) ((id) >> 5) 28 29 /* A full bank contains extra registers that we are not utilizing but still 30 * qualify as a single bank. 31 */ 32 #define SW_INIT_BANK_SIZE 0x18 33 34 static inline 35 struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev) 36 { 37 return container_of(rcdev, struct brcmstb_reset, rcdev); 38 } 39 40 static int brcmstb_reset_assert(struct reset_controller_dev *rcdev, 41 unsigned long id) 42 { 43 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; 44 struct brcmstb_reset *priv = to_brcmstb(rcdev); 45 46 writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET); 47 48 return 0; 49 } 50 51 static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev, 52 unsigned long id) 53 { 54 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; 55 struct brcmstb_reset *priv = to_brcmstb(rcdev); 56 57 writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR); 58 /* Maximum reset delay after de-asserting a line and seeing block 59 * operation is typically 14us for the worst case, build some slack 60 * here. 61 */ 62 usleep_range(100, 200); 63 64 return 0; 65 } 66 67 static int brcmstb_reset_status(struct reset_controller_dev *rcdev, 68 unsigned long id) 69 { 70 unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; 71 struct brcmstb_reset *priv = to_brcmstb(rcdev); 72 73 return readl_relaxed(priv->base + off + SW_INIT_STATUS) & 74 SW_INIT_BIT(id); 75 } 76 77 static const struct reset_control_ops brcmstb_reset_ops = { 78 .assert = brcmstb_reset_assert, 79 .deassert = brcmstb_reset_deassert, 80 .status = brcmstb_reset_status, 81 }; 82 83 static int brcmstb_reset_probe(struct platform_device *pdev) 84 { 85 struct device *kdev = &pdev->dev; 86 struct brcmstb_reset *priv; 87 struct resource *res; 88 89 priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL); 90 if (!priv) 91 return -ENOMEM; 92 93 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 94 if (!IS_ALIGNED(res->start, SW_INIT_BANK_SIZE) || 95 !IS_ALIGNED(resource_size(res), SW_INIT_BANK_SIZE)) { 96 dev_err(kdev, "incorrect register range\n"); 97 return -EINVAL; 98 } 99 100 priv->base = devm_ioremap_resource(kdev, res); 101 if (IS_ERR(priv->base)) 102 return PTR_ERR(priv->base); 103 104 dev_set_drvdata(kdev, priv); 105 106 priv->rcdev.owner = THIS_MODULE; 107 priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res), 108 SW_INIT_BANK_SIZE) * 32; 109 priv->rcdev.ops = &brcmstb_reset_ops; 110 priv->rcdev.of_node = kdev->of_node; 111 /* Use defaults: 1 cell and simple xlate function */ 112 113 return devm_reset_controller_register(kdev, &priv->rcdev); 114 } 115 116 static const struct of_device_id brcmstb_reset_of_match[] = { 117 { .compatible = "brcm,brcmstb-reset" }, 118 { /* sentinel */ } 119 }; 120 121 static struct platform_driver brcmstb_reset_driver = { 122 .probe = brcmstb_reset_probe, 123 .driver = { 124 .name = "brcmstb-reset", 125 .of_match_table = brcmstb_reset_of_match, 126 }, 127 }; 128 module_platform_driver(brcmstb_reset_driver); 129 130 MODULE_AUTHOR("Broadcom"); 131 MODULE_DESCRIPTION("Broadcom STB reset controller"); 132 MODULE_LICENSE("GPL"); 133