drivers/reset/reset-brcmstb-rescal.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /* Copyright (C) 2018-2020 Broadcom */
0003
0004 #include <linux/device.h>
0005 #include <linux/iopoll.h>
0006 #include <linux/module.h>
0007 #include <linux/of.h>
0008 #include <linux/platform_device.h>
0009 #include <linux/reset-controller.h>
0010
0011 #define BRCM_RESCAL_START   0x0
0012 #define  BRCM_RESCAL_START_BIT  BIT(0)
0013 #define BRCM_RESCAL_CTRL    0x4
0014 #define BRCM_RESCAL_STATUS  0x8
0015 #define  BRCM_RESCAL_STATUS_BIT BIT(0)
0016
0017 struct brcm_rescal_reset {
0018     void __iomem *base;
0019     struct device *dev;
0020     struct reset_controller_dev rcdev;
0021 };
0022
0023 static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
0024                  unsigned long id)
0025 {
0026     struct brcm_rescal_reset *data =
0027         container_of(rcdev, struct brcm_rescal_reset, rcdev);
0028     void __iomem *base = data->base;
0029     u32 reg;
0030     int ret;
0031
0032     reg = readl(base + BRCM_RESCAL_START);
0033     writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
0034     reg = readl(base + BRCM_RESCAL_START);
0035     if (!(reg & BRCM_RESCAL_START_BIT)) {
0036         dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
0037         return -EIO;
0038     }
0039
0040     ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
0041                  (reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
0042     if (ret) {
0043         dev_err(data->dev, "time out on SATA/PCIe rescal\n");
0044         return ret;
0045     }
0046
0047     reg = readl(base + BRCM_RESCAL_START);
0048     writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
0049
0050     dev_dbg(data->dev, "SATA/PCIe rescal success\n");
0051
0052     return 0;
0053 }
0054
0055 static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
0056                    const struct of_phandle_args *reset_spec)
0057 {
0058     /* This is needed if #reset-cells == 0. */
0059     return 0;
0060 }
0061
0062 static const struct reset_control_ops brcm_rescal_reset_ops = {
0063     .reset = brcm_rescal_reset_set,
0064 };
0065
0066 static int brcm_rescal_reset_probe(struct platform_device *pdev)
0067 {
0068     struct brcm_rescal_reset *data;
0069     struct resource *res;
0070
0071     data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
0072     if (!data)
0073         return -ENOMEM;
0074
0075     res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
0076     data->base = devm_ioremap_resource(&pdev->dev, res);
0077     if (IS_ERR(data->base))
0078         return PTR_ERR(data->base);
0079
0080     data->rcdev.owner = THIS_MODULE;
0081     data->rcdev.nr_resets = 1;
0082     data->rcdev.ops = &brcm_rescal_reset_ops;
0083     data->rcdev.of_node = pdev->dev.of_node;
0084     data->rcdev.of_xlate = brcm_rescal_reset_xlate;
0085     data->dev = &pdev->dev;
0086
0087     return devm_reset_controller_register(&pdev->dev, &data->rcdev);
0088 }
0089
0090 static const struct of_device_id brcm_rescal_reset_of_match[] = {
0091     { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
0092     { },
0093 };
0094 MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
0095
0096 static struct platform_driver brcm_rescal_reset_driver = {
0097     .probe = brcm_rescal_reset_probe,
0098     .driver = {
0099         .name   = "brcm-rescal-reset",
0100         .of_match_table = brcm_rescal_reset_of_match,
0101     }
0102 };
0103 module_platform_driver(brcm_rescal_reset_driver);
0104
0105 MODULE_AUTHOR("Broadcom");
0106 MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
0107 MODULE_LICENSE("GPL v2");