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