1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2018-2020 Broadcom */
3
4 #include <linux/device.h>
5 #include <linux/iopoll.h>
6 #include <linux/module.h>
7 #include <linux/of.h>
8 #include <linux/platform_device.h>
9 #include <linux/reset-controller.h>
10
11 #define BRCM_RESCAL_START 0x0
12 #define BRCM_RESCAL_START_BIT BIT(0)
13 #define BRCM_RESCAL_CTRL 0x4
14 #define BRCM_RESCAL_STATUS 0x8
15 #define BRCM_RESCAL_STATUS_BIT BIT(0)
16
17 struct brcm_rescal_reset {
18 void __iomem *base;
19 struct device *dev;
20 struct reset_controller_dev rcdev;
21 };
22
brcm_rescal_reset_set(struct reset_controller_dev * rcdev,unsigned long id)23 static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
24 unsigned long id)
25 {
26 struct brcm_rescal_reset *data =
27 container_of(rcdev, struct brcm_rescal_reset, rcdev);
28 void __iomem *base = data->base;
29 u32 reg;
30 int ret;
31
32 reg = readl(base + BRCM_RESCAL_START);
33 writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
34 reg = readl(base + BRCM_RESCAL_START);
35 if (!(reg & BRCM_RESCAL_START_BIT)) {
36 dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
37 return -EIO;
38 }
39
40 ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
41 (reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
42 if (ret) {
43 dev_err(data->dev, "time out on SATA/PCIe rescal\n");
44 return ret;
45 }
46
47 reg = readl(base + BRCM_RESCAL_START);
48 writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
49
50 dev_dbg(data->dev, "SATA/PCIe rescal success\n");
51
52 return 0;
53 }
54
brcm_rescal_reset_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)55 static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
56 const struct of_phandle_args *reset_spec)
57 {
58 /* This is needed if #reset-cells == 0. */
59 return 0;
60 }
61
62 static const struct reset_control_ops brcm_rescal_reset_ops = {
63 .reset = brcm_rescal_reset_set,
64 };
65
brcm_rescal_reset_probe(struct platform_device * pdev)66 static int brcm_rescal_reset_probe(struct platform_device *pdev)
67 {
68 struct brcm_rescal_reset *data;
69
70 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
71 if (!data)
72 return -ENOMEM;
73
74 data->base = devm_platform_ioremap_resource(pdev, 0);
75 if (IS_ERR(data->base))
76 return PTR_ERR(data->base);
77
78 data->rcdev.owner = THIS_MODULE;
79 data->rcdev.nr_resets = 1;
80 data->rcdev.ops = &brcm_rescal_reset_ops;
81 data->rcdev.of_node = pdev->dev.of_node;
82 data->rcdev.of_xlate = brcm_rescal_reset_xlate;
83 data->dev = &pdev->dev;
84
85 return devm_reset_controller_register(&pdev->dev, &data->rcdev);
86 }
87
88 static const struct of_device_id brcm_rescal_reset_of_match[] = {
89 { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
90 { },
91 };
92 MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
93
94 static struct platform_driver brcm_rescal_reset_driver = {
95 .probe = brcm_rescal_reset_probe,
96 .driver = {
97 .name = "brcm-rescal-reset",
98 .of_match_table = brcm_rescal_reset_of_match,
99 }
100 };
101 module_platform_driver(brcm_rescal_reset_driver);
102
103 MODULE_AUTHOR("Broadcom");
104 MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
105 MODULE_LICENSE("GPL v2");
106