drivers/power/reset/oxnas-restart.c

   1 // SPDX-License-Identifier: (GPL-2.0)
   2 /*
   3  * oxnas SoC reset driver
   4  * based on:
   5  * Microsemi MIPS SoC reset driver
   6  * and ox820_assert_system_reset() written by Ma Hajun <mahaijuns@gmail.com>
   7  *
   8  * Copyright (c) 2013 Ma Hajun <mahaijuns@gmail.com>
   9  * Copyright (c) 2017 Microsemi Corporation
  10  * Copyright (c) 2020 Daniel Golle <daniel@makrotopia.org>
  11  */
  12 #include <linux/delay.h>
  13 #include <linux/io.h>
  14 #include <linux/notifier.h>
  15 #include <linux/mfd/syscon.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_device.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/reboot.h>
  20 #include <linux/regmap.h>
  21
  22 /* bit numbers of reset control register */
  23 #define OX820_SYS_CTRL_RST_SCU                0
  24 #define OX820_SYS_CTRL_RST_COPRO              1
  25 #define OX820_SYS_CTRL_RST_ARM0               2
  26 #define OX820_SYS_CTRL_RST_ARM1               3
  27 #define OX820_SYS_CTRL_RST_USBHS              4
  28 #define OX820_SYS_CTRL_RST_USBHSPHYA          5
  29 #define OX820_SYS_CTRL_RST_MACA               6
  30 #define OX820_SYS_CTRL_RST_MAC                OX820_SYS_CTRL_RST_MACA
  31 #define OX820_SYS_CTRL_RST_PCIEA              7
  32 #define OX820_SYS_CTRL_RST_SGDMA              8
  33 #define OX820_SYS_CTRL_RST_CIPHER             9
  34 #define OX820_SYS_CTRL_RST_DDR                10
  35 #define OX820_SYS_CTRL_RST_SATA               11
  36 #define OX820_SYS_CTRL_RST_SATA_LINK          12
  37 #define OX820_SYS_CTRL_RST_SATA_PHY           13
  38 #define OX820_SYS_CTRL_RST_PCIEPHY            14
  39 #define OX820_SYS_CTRL_RST_STATIC             15
  40 #define OX820_SYS_CTRL_RST_GPIO               16
  41 #define OX820_SYS_CTRL_RST_UART1              17
  42 #define OX820_SYS_CTRL_RST_UART2              18
  43 #define OX820_SYS_CTRL_RST_MISC               19
  44 #define OX820_SYS_CTRL_RST_I2S                20
  45 #define OX820_SYS_CTRL_RST_SD                 21
  46 #define OX820_SYS_CTRL_RST_MACB               22
  47 #define OX820_SYS_CTRL_RST_PCIEB              23
  48 #define OX820_SYS_CTRL_RST_VIDEO              24
  49 #define OX820_SYS_CTRL_RST_DDR_PHY            25
  50 #define OX820_SYS_CTRL_RST_USBHSPHYB          26
  51 #define OX820_SYS_CTRL_RST_USBDEV             27
  52 #define OX820_SYS_CTRL_RST_ARMDBG             29
  53 #define OX820_SYS_CTRL_RST_PLLA               30
  54 #define OX820_SYS_CTRL_RST_PLLB               31
  55
  56 /* bit numbers of clock control register */
  57 #define OX820_SYS_CTRL_CLK_COPRO              0
  58 #define OX820_SYS_CTRL_CLK_DMA                1
  59 #define OX820_SYS_CTRL_CLK_CIPHER             2
  60 #define OX820_SYS_CTRL_CLK_SD                 3
  61 #define OX820_SYS_CTRL_CLK_SATA               4
  62 #define OX820_SYS_CTRL_CLK_I2S                5
  63 #define OX820_SYS_CTRL_CLK_USBHS              6
  64 #define OX820_SYS_CTRL_CLK_MACA               7
  65 #define OX820_SYS_CTRL_CLK_MAC                OX820_SYS_CTRL_CLK_MACA
  66 #define OX820_SYS_CTRL_CLK_PCIEA              8
  67 #define OX820_SYS_CTRL_CLK_STATIC             9
  68 #define OX820_SYS_CTRL_CLK_MACB               10
  69 #define OX820_SYS_CTRL_CLK_PCIEB              11
  70 #define OX820_SYS_CTRL_CLK_REF600             12
  71 #define OX820_SYS_CTRL_CLK_USBDEV             13
  72 #define OX820_SYS_CTRL_CLK_DDR                14
  73 #define OX820_SYS_CTRL_CLK_DDRPHY             15
  74 #define OX820_SYS_CTRL_CLK_DDRCK              16
  75
  76 /* Regmap offsets */
  77 #define OX820_CLK_SET_REGOFFSET               0x2c
  78 #define OX820_CLK_CLR_REGOFFSET               0x30
  79 #define OX820_RST_SET_REGOFFSET               0x34
  80 #define OX820_RST_CLR_REGOFFSET               0x38
  81 #define OX820_SECONDARY_SEL_REGOFFSET         0x14
  82 #define OX820_TERTIARY_SEL_REGOFFSET          0x8c
  83 #define OX820_QUATERNARY_SEL_REGOFFSET        0x94
  84 #define OX820_DEBUG_SEL_REGOFFSET             0x9c
  85 #define OX820_ALTERNATIVE_SEL_REGOFFSET       0xa4
  86 #define OX820_PULLUP_SEL_REGOFFSET            0xac
  87 #define OX820_SEC_SECONDARY_SEL_REGOFFSET     0x100014
  88 #define OX820_SEC_TERTIARY_SEL_REGOFFSET      0x10008c
  89 #define OX820_SEC_QUATERNARY_SEL_REGOFFSET    0x100094
  90 #define OX820_SEC_DEBUG_SEL_REGOFFSET         0x10009c
  91 #define OX820_SEC_ALTERNATIVE_SEL_REGOFFSET   0x1000a4
  92 #define OX820_SEC_PULLUP_SEL_REGOFFSET        0x1000ac
  93
  94 struct oxnas_restart_context {
  95         struct regmap *sys_ctrl;
  96         struct notifier_block restart_handler;
  97 };
  98
  99 static int ox820_restart_handle(struct notifier_block *this,
 100                                  unsigned long mode, void *cmd)
 101 {
 102         struct oxnas_restart_context *ctx = container_of(this, struct
 103                                                         oxnas_restart_context,
 104                                                         restart_handler);
 105         u32 value;
 106
 107         /*
 108          * Assert reset to cores as per power on defaults
 109          * Don't touch the DDR interface as things will come to an impromptu
 110          * stop NB Possibly should be asserting reset for PLLB, but there are
 111          * timing concerns here according to the docs
 112          */
 113         value = BIT(OX820_SYS_CTRL_RST_COPRO)           |
 114                 BIT(OX820_SYS_CTRL_RST_USBHS)           |
 115                 BIT(OX820_SYS_CTRL_RST_USBHSPHYA)       |
 116                 BIT(OX820_SYS_CTRL_RST_MACA)            |
 117                 BIT(OX820_SYS_CTRL_RST_PCIEA)           |
 118                 BIT(OX820_SYS_CTRL_RST_SGDMA)           |
 119                 BIT(OX820_SYS_CTRL_RST_CIPHER)          |
 120                 BIT(OX820_SYS_CTRL_RST_SATA)            |
 121                 BIT(OX820_SYS_CTRL_RST_SATA_LINK)       |
 122                 BIT(OX820_SYS_CTRL_RST_SATA_PHY)        |
 123                 BIT(OX820_SYS_CTRL_RST_PCIEPHY)         |
 124                 BIT(OX820_SYS_CTRL_RST_STATIC)          |
 125                 BIT(OX820_SYS_CTRL_RST_UART1)           |
 126                 BIT(OX820_SYS_CTRL_RST_UART2)           |
 127                 BIT(OX820_SYS_CTRL_RST_MISC)            |
 128                 BIT(OX820_SYS_CTRL_RST_I2S)             |
 129                 BIT(OX820_SYS_CTRL_RST_SD)              |
 130                 BIT(OX820_SYS_CTRL_RST_MACB)            |
 131                 BIT(OX820_SYS_CTRL_RST_PCIEB)           |
 132                 BIT(OX820_SYS_CTRL_RST_VIDEO)           |
 133                 BIT(OX820_SYS_CTRL_RST_USBHSPHYB)       |
 134                 BIT(OX820_SYS_CTRL_RST_USBDEV);
 135
 136         regmap_write(ctx->sys_ctrl, OX820_RST_SET_REGOFFSET, value);
 137
 138         /* Release reset to cores as per power on defaults */
 139         regmap_write(ctx->sys_ctrl, OX820_RST_CLR_REGOFFSET,
 140                         BIT(OX820_SYS_CTRL_RST_GPIO));
 141
 142         /*
 143          * Disable clocks to cores as per power-on defaults - must leave DDR
 144          * related clocks enabled otherwise we'll stop rather abruptly.
 145          */
 146         value = BIT(OX820_SYS_CTRL_CLK_COPRO)           |
 147                 BIT(OX820_SYS_CTRL_CLK_DMA)             |
 148                 BIT(OX820_SYS_CTRL_CLK_CIPHER)          |
 149                 BIT(OX820_SYS_CTRL_CLK_SD)              |
 150                 BIT(OX820_SYS_CTRL_CLK_SATA)            |
 151                 BIT(OX820_SYS_CTRL_CLK_I2S)             |
 152                 BIT(OX820_SYS_CTRL_CLK_USBHS)           |
 153                 BIT(OX820_SYS_CTRL_CLK_MAC)             |
 154                 BIT(OX820_SYS_CTRL_CLK_PCIEA)           |
 155                 BIT(OX820_SYS_CTRL_CLK_STATIC)          |
 156                 BIT(OX820_SYS_CTRL_CLK_MACB)            |
 157                 BIT(OX820_SYS_CTRL_CLK_PCIEB)           |
 158                 BIT(OX820_SYS_CTRL_CLK_REF600)          |
 159                 BIT(OX820_SYS_CTRL_CLK_USBDEV);
 160
 161         regmap_write(ctx->sys_ctrl, OX820_CLK_CLR_REGOFFSET, value);
 162
 163         /* Enable clocks to cores as per power-on defaults */
 164
 165         /* Set sys-control pin mux'ing as per power-on defaults */
 166         regmap_write(ctx->sys_ctrl, OX820_SECONDARY_SEL_REGOFFSET, 0);
 167         regmap_write(ctx->sys_ctrl, OX820_TERTIARY_SEL_REGOFFSET, 0);
 168         regmap_write(ctx->sys_ctrl, OX820_QUATERNARY_SEL_REGOFFSET, 0);
 169         regmap_write(ctx->sys_ctrl, OX820_DEBUG_SEL_REGOFFSET, 0);
 170         regmap_write(ctx->sys_ctrl, OX820_ALTERNATIVE_SEL_REGOFFSET, 0);
 171         regmap_write(ctx->sys_ctrl, OX820_PULLUP_SEL_REGOFFSET, 0);
 172
 173         regmap_write(ctx->sys_ctrl, OX820_SEC_SECONDARY_SEL_REGOFFSET, 0);
 174         regmap_write(ctx->sys_ctrl, OX820_SEC_TERTIARY_SEL_REGOFFSET, 0);
 175         regmap_write(ctx->sys_ctrl, OX820_SEC_QUATERNARY_SEL_REGOFFSET, 0);
 176         regmap_write(ctx->sys_ctrl, OX820_SEC_DEBUG_SEL_REGOFFSET, 0);
 177         regmap_write(ctx->sys_ctrl, OX820_SEC_ALTERNATIVE_SEL_REGOFFSET, 0);
 178         regmap_write(ctx->sys_ctrl, OX820_SEC_PULLUP_SEL_REGOFFSET, 0);
 179
 180         /*
 181          * No need to save any state, as the ROM loader can determine whether
 182          * reset is due to power cycling or programatic action, just hit the
 183          * (self-clearing) CPU reset bit of the block reset register
 184          */
 185         value =
 186                 BIT(OX820_SYS_CTRL_RST_SCU) |
 187                 BIT(OX820_SYS_CTRL_RST_ARM0) |
 188                 BIT(OX820_SYS_CTRL_RST_ARM1);
 189
 190         regmap_write(ctx->sys_ctrl, OX820_RST_SET_REGOFFSET, value);
 191
 192         pr_emerg("Unable to restart system\n");
 193         return NOTIFY_DONE;
 194 }
 195
 196 static int ox820_restart_probe(struct platform_device *pdev)
 197 {
 198         struct oxnas_restart_context *ctx;
 199         struct regmap *sys_ctrl;
 200         struct device *dev = &pdev->dev;
 201         int err = 0;
 202
 203         sys_ctrl = syscon_node_to_regmap(pdev->dev.of_node);
 204         if (IS_ERR(sys_ctrl))
 205                 return PTR_ERR(sys_ctrl);
 206
 207         ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
 208         if (!ctx)
 209                 return -ENOMEM;
 210
 211         ctx->sys_ctrl = sys_ctrl;
 212         ctx->restart_handler.notifier_call = ox820_restart_handle;
 213         ctx->restart_handler.priority = 192;
 214         err = register_restart_handler(&ctx->restart_handler);
 215         if (err)
 216                 dev_err(dev, "can't register restart notifier (err=%d)\n", err);
 217
 218         return err;
 219 }
 220
 221 static const struct of_device_id ox820_restart_of_match[] = {
 222         { .compatible = "oxsemi,ox820-sys-ctrl" },
 223         {}
 224 };
 225
 226 static struct platform_driver ox820_restart_driver = {
 227         .probe = ox820_restart_probe,
 228         .driver = {
 229                 .name = "ox820-chip-reset",
 230                 .of_match_table = ox820_restart_of_match,
 231         },
 232 };
 233 builtin_platform_driver(ox820_restart_driver);