drivers/reset/reset-hsdk.c

   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         struct resource *mem;
  96
  97         rst = devm_kzalloc(&pdev->dev, sizeof(*rst), GFP_KERNEL);
  98         if (!rst)
  99                 return -ENOMEM;
 100
 101         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 102         rst->regs_ctl = devm_ioremap_resource(&pdev->dev, mem);
 103         if (IS_ERR(rst->regs_ctl))
 104                 return PTR_ERR(rst->regs_ctl);
 105
 106         mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 107         rst->regs_rst = devm_ioremap_resource(&pdev->dev, mem);
 108         if (IS_ERR(rst->regs_rst))
 109                 return PTR_ERR(rst->regs_rst);
 110
 111         spin_lock_init(&rst->lock);
 112
 113         rst->rcdev.owner = THIS_MODULE;
 114         rst->rcdev.ops = &hsdk_reset_ops;
 115         rst->rcdev.of_node = pdev->dev.of_node;
 116         rst->rcdev.nr_resets = HSDK_MAX_RESETS;
 117         rst->rcdev.of_reset_n_cells = 1;
 118
 119         return reset_controller_register(&rst->rcdev);
 120 }
 121
 122 static const struct of_device_id hsdk_reset_dt_match[] = {
 123         { .compatible = "snps,hsdk-reset" },
 124         { },
 125 };
 126
 127 static struct platform_driver hsdk_reset_driver = {
 128         .probe  = hsdk_reset_probe,
 129         .driver = {
 130                 .name = "hsdk-reset",
 131                 .of_match_table = hsdk_reset_dt_match,
 132         },
 133 };
 134 builtin_platform_driver(hsdk_reset_driver);
 135
 136 MODULE_AUTHOR("Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>");
 137 MODULE_DESCRIPTION("Synopsys HSDK SDP reset driver");
 138 MODULE_LICENSE("GPL v2");