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 17struct 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 34static inline 35struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev) 36{ 37 return container_of(rcdev, struct brcmstb_reset, rcdev); 38} 39 40static 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 51static 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 67static 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 77static 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 83static 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 priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 94 if (IS_ERR(priv->base)) 95 return PTR_ERR(priv->base); 96 97 dev_set_drvdata(kdev, priv); 98 99 priv->rcdev.owner = THIS_MODULE; 100 priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res), 101 SW_INIT_BANK_SIZE) * 32; 102 priv->rcdev.ops = &brcmstb_reset_ops; 103 priv->rcdev.of_node = kdev->of_node; 104 /* Use defaults: 1 cell and simple xlate function */ 105 106 return devm_reset_controller_register(kdev, &priv->rcdev); 107} 108 109static const struct of_device_id brcmstb_reset_of_match[] = { 110 { .compatible = "brcm,brcmstb-reset" }, 111 { /* sentinel */ } 112}; 113MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match); 114 115static struct platform_driver brcmstb_reset_driver = { 116 .probe = brcmstb_reset_probe, 117 .driver = { 118 .name = "brcmstb-reset", 119 .of_match_table = brcmstb_reset_of_match, 120 }, 121}; 122module_platform_driver(brcmstb_reset_driver); 123 124MODULE_AUTHOR("Broadcom"); 125MODULE_DESCRIPTION("Broadcom STB reset controller"); 126MODULE_LICENSE("GPL"); 127