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linux-next/drivers/reset/reset-brcmstb-rescal.c
Jim Quinlan 4cf176e523 reset: Add Broadcom STB RESCAL reset controller
On BCM7216 there is a special purpose reset controller named RESCAL
(reset calibration) which is necessary for SATA and PCIe0/1 to operate
correctly. This commit adds support for such a reset controller to be
available.

Signed-off-by: Jim Quinlan <jim2101024@gmail.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
2020-01-06 10:02:03 +01:00

108 lines
2.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2018-2020 Broadcom */
#include <linux/device.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#define BRCM_RESCAL_START 0x0
#define BRCM_RESCAL_START_BIT BIT(0)
#define BRCM_RESCAL_CTRL 0x4
#define BRCM_RESCAL_STATUS 0x8
#define BRCM_RESCAL_STATUS_BIT BIT(0)
struct brcm_rescal_reset {
void __iomem *base;
struct device *dev;
struct reset_controller_dev rcdev;
};
static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct brcm_rescal_reset *data =
container_of(rcdev, struct brcm_rescal_reset, rcdev);
void __iomem *base = data->base;
u32 reg;
int ret;
reg = readl(base + BRCM_RESCAL_START);
writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
reg = readl(base + BRCM_RESCAL_START);
if (!(reg & BRCM_RESCAL_START_BIT)) {
dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
return -EIO;
}
ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
!(reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
if (ret) {
dev_err(data->dev, "time out on SATA/PCIe rescal\n");
return ret;
}
reg = readl(base + BRCM_RESCAL_START);
writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
dev_dbg(data->dev, "SATA/PCIe rescal success\n");
return 0;
}
static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec)
{
/* This is needed if #reset-cells == 0. */
return 0;
}
static const struct reset_control_ops brcm_rescal_reset_ops = {
.reset = brcm_rescal_reset_set,
};
static int brcm_rescal_reset_probe(struct platform_device *pdev)
{
struct brcm_rescal_reset *data;
struct resource *res;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(data->base))
return PTR_ERR(data->base);
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = 1;
data->rcdev.ops = &brcm_rescal_reset_ops;
data->rcdev.of_node = pdev->dev.of_node;
data->rcdev.of_xlate = brcm_rescal_reset_xlate;
data->dev = &pdev->dev;
return devm_reset_controller_register(&pdev->dev, &data->rcdev);
}
static const struct of_device_id brcm_rescal_reset_of_match[] = {
{ .compatible = "brcm,bcm7216-pcie-sata-rescal" },
{ },
};
MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
static struct platform_driver brcm_rescal_reset_driver = {
.probe = brcm_rescal_reset_probe,
.driver = {
.name = "brcm-rescal-reset",
.of_match_table = brcm_rescal_reset_of_match,
}
};
module_platform_driver(brcm_rescal_reset_driver);
MODULE_AUTHOR("Broadcom");
MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
MODULE_LICENSE("GPL v2");