LXR linux/drivers/reset/reset-brcmstb.c

   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        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  94        priv->base = devm_ioremap_resource(kdev, res);
  95        if (IS_ERR(priv->base))
  96                return PTR_ERR(priv->base);
  97
  98        dev_set_drvdata(kdev, priv);
  99
 100        priv->rcdev.owner = THIS_MODULE;
 101        priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),
 102                                                   SW_INIT_BANK_SIZE) * 32;
 103        priv->rcdev.ops = &brcmstb_reset_ops;
 104        priv->rcdev.of_node = kdev->of_node;
 105        /* Use defaults: 1 cell and simple xlate function */
 106
 107        return devm_reset_controller_register(kdev, &priv->rcdev);
 108}
 109
 110static const struct of_device_id brcmstb_reset_of_match[] = {
 111        { .compatible = "brcm,brcmstb-reset" },
 112        { /* sentinel */ }
 113};
 114MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match);
 115
 116static struct platform_driver brcmstb_reset_driver = {
 117        .probe  = brcmstb_reset_probe,
 118        .driver = {
 119                .name = "brcmstb-reset",
 120                .of_match_table = brcmstb_reset_of_match,
 121        },
 122};
 123module_platform_driver(brcmstb_reset_driver);
 124
 125MODULE_AUTHOR("Broadcom");
 126MODULE_DESCRIPTION("Broadcom STB reset controller");
 127MODULE_LICENSE("GPL");
 128