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77750bc089
Add support for resetting blocks through the Linux reset controller subsystem when reset lines are provided through a SW_INIT-style reset controller on Broadcom STB SoCs. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
133 lines
3.5 KiB
C
133 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Broadcom STB generic reset controller for SW_INIT style reset controller
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*
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* Author: Florian Fainelli <f.fainelli@gmail.com>
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* Copyright (C) 2018 Broadcom
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*/
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/reset-controller.h>
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#include <linux/types.h>
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struct brcmstb_reset {
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void __iomem *base;
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struct reset_controller_dev rcdev;
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};
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#define SW_INIT_SET 0x00
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#define SW_INIT_CLEAR 0x04
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#define SW_INIT_STATUS 0x08
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#define SW_INIT_BIT(id) BIT((id) & 0x1f)
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#define SW_INIT_BANK(id) ((id) >> 5)
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/* A full bank contains extra registers that we are not utilizing but still
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* qualify as a single bank.
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*/
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#define SW_INIT_BANK_SIZE 0x18
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static inline
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struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)
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{
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return container_of(rcdev, struct brcmstb_reset, rcdev);
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}
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static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
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struct brcmstb_reset *priv = to_brcmstb(rcdev);
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writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);
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return 0;
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}
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static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
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struct brcmstb_reset *priv = to_brcmstb(rcdev);
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writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);
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/* Maximum reset delay after de-asserting a line and seeing block
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* operation is typically 14us for the worst case, build some slack
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* here.
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*/
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usleep_range(100, 200);
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return 0;
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}
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static int brcmstb_reset_status(struct reset_controller_dev *rcdev,
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unsigned long id)
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{
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unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
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struct brcmstb_reset *priv = to_brcmstb(rcdev);
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return readl_relaxed(priv->base + off + SW_INIT_STATUS) &
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SW_INIT_BIT(id);
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}
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static const struct reset_control_ops brcmstb_reset_ops = {
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.assert = brcmstb_reset_assert,
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.deassert = brcmstb_reset_deassert,
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.status = brcmstb_reset_status,
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};
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static int brcmstb_reset_probe(struct platform_device *pdev)
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{
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struct device *kdev = &pdev->dev;
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struct brcmstb_reset *priv;
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struct resource *res;
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priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!IS_ALIGNED(res->start, SW_INIT_BANK_SIZE) ||
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!IS_ALIGNED(resource_size(res), SW_INIT_BANK_SIZE)) {
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dev_err(kdev, "incorrect register range\n");
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return -EINVAL;
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}
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priv->base = devm_ioremap_resource(kdev, res);
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if (IS_ERR(priv->base))
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return PTR_ERR(priv->base);
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dev_set_drvdata(kdev, priv);
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priv->rcdev.owner = THIS_MODULE;
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priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),
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SW_INIT_BANK_SIZE) * 32;
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priv->rcdev.ops = &brcmstb_reset_ops;
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priv->rcdev.of_node = kdev->of_node;
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/* Use defaults: 1 cell and simple xlate function */
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return devm_reset_controller_register(kdev, &priv->rcdev);
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}
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static const struct of_device_id brcmstb_reset_of_match[] = {
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{ .compatible = "brcm,brcmstb-reset" },
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{ /* sentinel */ }
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};
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static struct platform_driver brcmstb_reset_driver = {
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.probe = brcmstb_reset_probe,
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.driver = {
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.name = "brcmstb-reset",
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.of_match_table = brcmstb_reset_of_match,
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},
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};
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module_platform_driver(brcmstb_reset_driver);
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MODULE_AUTHOR("Broadcom");
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MODULE_DESCRIPTION("Broadcom STB reset controller");
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MODULE_LICENSE("GPL");
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