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 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 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 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