drivers/misc/rockchip-efuse.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * eFuse driver for Rockchip devices
   4  *
   5  * Copyright 2017, Theobroma Systems Design und Consulting GmbH
   6  * Written by Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
   7  */
   8
   9 #include <common.h>
  10 #include <asm/io.h>
  11 #include <command.h>
  12 #include <display_options.h>
  13 #include <dm.h>
  14 #include <linux/bitops.h>
  15 #include <linux/delay.h>
  16 #include <misc.h>
  17
  18 #define RK3399_A_SHIFT          16
  19 #define RK3399_A_MASK           0x3ff
  20 #define RK3399_NFUSES           32
  21 #define RK3399_BYTES_PER_FUSE   4
  22 #define RK3399_STROBSFTSEL      BIT(9)
  23 #define RK3399_RSB              BIT(7)
  24 #define RK3399_PD               BIT(5)
  25 #define RK3399_PGENB            BIT(3)
  26 #define RK3399_LOAD             BIT(2)
  27 #define RK3399_STROBE           BIT(1)
  28 #define RK3399_CSB              BIT(0)
  29
  30 struct rockchip_efuse_regs {
  31         u32 ctrl;      /* 0x00  efuse control register */
  32         u32 dout;      /* 0x04  efuse data out register */
  33         u32 rf;        /* 0x08  efuse redundancy bit used register */
  34         u32 _rsvd0;
  35         u32 jtag_pass; /* 0x10  JTAG password */
  36         u32 strobe_finish_ctrl;
  37                        /* 0x14  efuse strobe finish control register */
  38 };
  39
  40 struct rockchip_efuse_plat {
  41         void __iomem *base;
  42         struct clk *clk;
  43 };
  44
  45 #if defined(DEBUG)
  46 static int dump_efuses(struct cmd_tbl *cmdtp, int flag,
  47                        int argc, char *const argv[])
  48 {
  49         /*
  50          * N.B.: This function is tailored towards the RK3399 and assumes that
  51          *       there's always 32 fuses x 32 bits (i.e. 128 bytes of data) to
  52          *       be read.
  53          */
  54
  55         struct udevice *dev;
  56         u8 fuses[128];
  57         int ret;
  58
  59         /* retrieve the device */
  60         ret = uclass_get_device_by_driver(UCLASS_MISC,
  61                                           DM_DRIVER_GET(rockchip_efuse), &dev);
  62         if (ret) {
  63                 printf("%s: no misc-device found\n", __func__);
  64                 return 0;
  65         }
  66
  67         ret = misc_read(dev, 0, &fuses, sizeof(fuses));
  68         if (ret < 0) {
  69                 printf("%s: misc_read failed\n", __func__);
  70                 return 0;
  71         }
  72
  73         printf("efuse-contents:\n");
  74         print_buffer(0, fuses, 1, 128, 16);
  75
  76         return 0;
  77 }
  78
  79 U_BOOT_CMD(
  80         rk3399_dump_efuses, 1, 1, dump_efuses,
  81         "Dump the content of the efuses",
  82         ""
  83 );
  84 #endif
  85
  86 static int rockchip_rk3399_efuse_read(struct udevice *dev, int offset,
  87                                       void *buf, int size)
  88 {
  89         struct rockchip_efuse_plat *plat = dev_get_plat(dev);
  90         struct rockchip_efuse_regs *efuse =
  91                 (struct rockchip_efuse_regs *)plat->base;
  92
  93         unsigned int addr_start, addr_end, addr_offset;
  94         u32 out_value;
  95         u8  bytes[RK3399_NFUSES * RK3399_BYTES_PER_FUSE];
  96         int i = 0;
  97         u32 addr;
  98
  99         addr_start = offset / RK3399_BYTES_PER_FUSE;
 100         addr_offset = offset % RK3399_BYTES_PER_FUSE;
 101         addr_end = DIV_ROUND_UP(offset + size, RK3399_BYTES_PER_FUSE);
 102
 103         /* cap to the size of the efuse block */
 104         if (addr_end > RK3399_NFUSES)
 105                 addr_end = RK3399_NFUSES;
 106
 107         writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
 108                &efuse->ctrl);
 109         udelay(1);
 110         for (addr = addr_start; addr < addr_end; addr++) {
 111                 setbits_le32(&efuse->ctrl,
 112                              RK3399_STROBE | (addr << RK3399_A_SHIFT));
 113                 udelay(1);
 114                 out_value = readl(&efuse->dout);
 115                 clrbits_le32(&efuse->ctrl, RK3399_STROBE);
 116                 udelay(1);
 117
 118                 memcpy(&bytes[i], &out_value, RK3399_BYTES_PER_FUSE);
 119                 i += RK3399_BYTES_PER_FUSE;
 120         }
 121
 122         /* Switch to standby mode */
 123         writel(RK3399_PD | RK3399_CSB, &efuse->ctrl);
 124
 125         memcpy(buf, bytes + addr_offset, size);
 126
 127         return 0;
 128 }
 129
 130 static int rockchip_efuse_read(struct udevice *dev, int offset,
 131                                void *buf, int size)
 132 {
 133         return rockchip_rk3399_efuse_read(dev, offset, buf, size);
 134 }
 135
 136 static const struct misc_ops rockchip_efuse_ops = {
 137         .read = rockchip_efuse_read,
 138 };
 139
 140 static int rockchip_efuse_of_to_plat(struct udevice *dev)
 141 {
 142         struct rockchip_efuse_plat *plat = dev_get_plat(dev);
 143
 144         plat->base = dev_read_addr_ptr(dev);
 145         return 0;
 146 }
 147
 148 static const struct udevice_id rockchip_efuse_ids[] = {
 149         { .compatible = "rockchip,rk3399-efuse" },
 150         {}
 151 };
 152
 153 U_BOOT_DRIVER(rockchip_efuse) = {
 154         .name = "rockchip_efuse",
 155         .id = UCLASS_MISC,
 156         .of_match = rockchip_efuse_ids,
 157         .of_to_plat = rockchip_efuse_of_to_plat,
 158         .plat_auto      = sizeof(struct rockchip_efuse_plat),
 159         .ops = &rockchip_efuse_ops,
 160 };