1 /* 2 * Copyright (C) 2017 Synopsys. 3 * 4 * Synopsys HSDK Development platform reset driver. 5 * 6 * This file is licensed under the terms of the GNU General Public 7 * License version 2. This program is licensed "as is" without any 8 * warranty of any kind, whether express or implied. 9 */ 10 11 #include <linux/delay.h> 12 #include <linux/io.h> 13 #include <linux/iopoll.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 #include <linux/platform_device.h> 17 #include <linux/reset-controller.h> 18 #include <linux/slab.h> 19 #include <linux/types.h> 20 21 #define to_hsdk_rst(p) container_of((p), struct hsdk_rst, rcdev) 22 23 struct hsdk_rst { 24 void __iomem *regs_ctl; 25 void __iomem *regs_rst; 26 spinlock_t lock; 27 struct reset_controller_dev rcdev; 28 }; 29 30 static const u32 rst_map[] = { 31 BIT(16), /* APB_RST */ 32 BIT(17), /* AXI_RST */ 33 BIT(18), /* ETH_RST */ 34 BIT(19), /* USB_RST */ 35 BIT(20), /* SDIO_RST */ 36 BIT(21), /* HDMI_RST */ 37 BIT(22), /* GFX_RST */ 38 BIT(25), /* DMAC_RST */ 39 BIT(31), /* EBI_RST */ 40 }; 41 42 #define HSDK_MAX_RESETS ARRAY_SIZE(rst_map) 43 44 #define CGU_SYS_RST_CTRL 0x0 45 #define CGU_IP_SW_RESET 0x0 46 #define CGU_IP_SW_RESET_DELAY_SHIFT 16 47 #define CGU_IP_SW_RESET_DELAY_MASK GENMASK(31, CGU_IP_SW_RESET_DELAY_SHIFT) 48 #define CGU_IP_SW_RESET_DELAY 0 49 #define CGU_IP_SW_RESET_RESET BIT(0) 50 #define SW_RESET_TIMEOUT 10000 51 52 static void hsdk_reset_config(struct hsdk_rst *rst, unsigned long id) 53 { 54 writel(rst_map[id], rst->regs_ctl + CGU_SYS_RST_CTRL); 55 } 56 57 static int hsdk_reset_do(struct hsdk_rst *rst) 58 { 59 u32 reg; 60 61 reg = readl(rst->regs_rst + CGU_IP_SW_RESET); 62 reg &= ~CGU_IP_SW_RESET_DELAY_MASK; 63 reg |= CGU_IP_SW_RESET_DELAY << CGU_IP_SW_RESET_DELAY_SHIFT; 64 reg |= CGU_IP_SW_RESET_RESET; 65 writel(reg, rst->regs_rst + CGU_IP_SW_RESET); 66 67 /* wait till reset bit is back to 0 */ 68 return readl_poll_timeout_atomic(rst->regs_rst + CGU_IP_SW_RESET, reg, 69 !(reg & CGU_IP_SW_RESET_RESET), 5, SW_RESET_TIMEOUT); 70 } 71 72 static int hsdk_reset_reset(struct reset_controller_dev *rcdev, 73 unsigned long id) 74 { 75 struct hsdk_rst *rst = to_hsdk_rst(rcdev); 76 unsigned long flags; 77 int ret; 78 79 spin_lock_irqsave(&rst->lock, flags); 80 hsdk_reset_config(rst, id); 81 ret = hsdk_reset_do(rst); 82 spin_unlock_irqrestore(&rst->lock, flags); 83 84 return ret; 85 } 86 87 static const struct reset_control_ops hsdk_reset_ops = { 88 .reset = hsdk_reset_reset, 89 .deassert = hsdk_reset_reset, 90 }; 91 92 static int hsdk_reset_probe(struct platform_device *pdev) 93 { 94 struct hsdk_rst *rst; 95 96 rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL); 97 if (!rst) 98 return -ENOMEM; 99 100 rst->regs_ctl = devm_platform_ioremap_resource(pdev, 0); 101 if (IS_ERR(rst->regs_ctl)) 102 return PTR_ERR(rst->regs_ctl); 103 104 rst->regs_rst = devm_platform_ioremap_resource(pdev, 1); 105 if (IS_ERR(rst->regs_rst)) 106 return PTR_ERR(rst->regs_rst); 107 108 spin_lock_init(&rst->lock); 109 110 rst->rcdev.owner = THIS_MODULE; 111 rst->rcdev.ops = &hsdk_reset_ops; 112 rst->rcdev.of_node = pdev->dev.of_node; 113 rst->rcdev.nr_resets = HSDK_MAX_RESETS; 114 rst->rcdev.of_reset_n_cells = 1; 115 116 return reset_controller_register(&rst->rcdev); 117 } 118 119 static const struct of_device_id hsdk_reset_dt_match[] = { 120 { .compatible = "snps,hsdk-reset" }, 121 { }, 122 }; 123 124 static struct platform_driver hsdk_reset_driver = { 125 .probe = hsdk_reset_probe, 126 .driver = { 127 .name = "hsdk-reset", 128 .of_match_table = hsdk_reset_dt_match, 129 }, 130 }; 131 builtin_platform_driver(hsdk_reset_driver); 132 133 MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>"); 134 MODULE_DESCRIPTION("Synopsys HSDK SDP reset driver"); 135 MODULE_LICENSE("GPL v2"); 136