drivers/misc/rockchip-efuse.c

   1 /*
   2  * eFuse driver for Rockchip devices
   3  *
   4  * Copyright 2017, Theobroma Systems Design und Consulting GmbH
   5  * Written by Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
   6  *
   7  * SPDX-License-Identifier:     GPL-2.0+
   8  */
   9
  10 #include <common.h>
  11 #include <asm/io.h>
  12 #include <command.h>
  13 #include <display_options.h>
  14 #include <dm.h>
  15 #include <linux/bitops.h>
  16 #include <linux/delay.h>
  17 #include <misc.h>
  18
  19 #define RK3399_A_SHIFT          16
  20 #define RK3399_A_MASK           0x3ff
  21 #define RK3399_NFUSES           32
  22 #define RK3399_BYTES_PER_FUSE   4
  23 #define RK3399_STROBSFTSEL      BIT(9)
  24 #define RK3399_RSB              BIT(7)
  25 #define RK3399_PD               BIT(5)
  26 #define RK3399_PGENB            BIT(3)
  27 #define RK3399_LOAD             BIT(2)
  28 #define RK3399_STROBE           BIT(1)
  29 #define RK3399_CSB              BIT(0)
  30
  31 struct rockchip_efuse_regs {
  32         u32 ctrl;      /* 0x00  efuse control register */
  33         u32 dout;      /* 0x04  efuse data out register */
  34         u32 rf;        /* 0x08  efuse redundancy bit used register */
  35         u32 _rsvd0;
  36         u32 jtag_pass; /* 0x10  JTAG password */
  37         u32 strobe_finish_ctrl;
  38                        /* 0x14  efuse strobe finish control register */
  39 };
  40
  41 struct rockchip_efuse_platdata {
  42         void __iomem *base;
  43         struct clk *clk;
  44 };
  45
  46 #if defined(DEBUG)
  47 static int dump_efuses(cmd_tbl_t *cmdtp, int flag,
  48                        int argc, char * const argv[])
  49 {
  50         /*
  51          * N.B.: This function is tailored towards the RK3399 and assumes that
  52          *       there's always 32 fuses x 32 bits (i.e. 128 bytes of data) to
  53          *       be read.
  54          */
  55
  56         struct udevice *dev;
  57         u8 fuses[128];
  58         int ret;
  59
  60         /* retrieve the device */
  61         ret = uclass_get_device_by_driver(UCLASS_MISC,
  62                                           DM_GET_DRIVER(rockchip_efuse), &dev);
  63         if (ret) {
  64                 printf("%s: no misc-device found\n", __func__);
  65                 return 0;
  66         }
  67
  68         ret = misc_read(dev, 0, &fuses, sizeof(fuses));
  69         if (ret) {
  70                 printf("%s: misc_read failed\n", __func__);
  71                 return 0;
  72         }
  73
  74         printf("efuse-contents:\n");
  75         print_buffer(0, fuses, 1, 128, 16);
  76
  77         return 0;
  78 }
  79
  80 U_BOOT_CMD(
  81         rk3399_dump_efuses, 1, 1, dump_efuses,
  82         "Dump the content of the efuses",
  83         ""
  84 );
  85 #endif
  86
  87 static int rockchip_rk3399_efuse_read(struct udevice *dev, int offset,
  88                                       void *buf, int size)
  89 {
  90         struct rockchip_efuse_platdata *plat = dev_get_platdata(dev);
  91         struct rockchip_efuse_regs *efuse =
  92                 (struct rockchip_efuse_regs *)plat->base;
  93
  94         unsigned int addr_start, addr_end, addr_offset;
  95         u32 out_value;
  96         u8  bytes[RK3399_NFUSES * RK3399_BYTES_PER_FUSE];
  97         int i = 0;
  98         u32 addr;
  99
 100         addr_start = offset / RK3399_BYTES_PER_FUSE;
 101         addr_offset = offset % RK3399_BYTES_PER_FUSE;
 102         addr_end = DIV_ROUND_UP(offset + size, RK3399_BYTES_PER_FUSE);
 103
 104         /* cap to the size of the efuse block */
 105         if (addr_end > RK3399_NFUSES)
 106                 addr_end = RK3399_NFUSES;
 107
 108         writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
 109                &efuse->ctrl);
 110         udelay(1);
 111         for (addr = addr_start; addr < addr_end; addr++) {
 112                 setbits_le32(&efuse->ctrl,
 113                              RK3399_STROBE | (addr << RK3399_A_SHIFT));
 114                 udelay(1);
 115                 out_value = readl(&efuse->dout);
 116                 clrbits_le32(&efuse->ctrl, RK3399_STROBE);
 117                 udelay(1);
 118
 119                 memcpy(&bytes[i], &out_value, RK3399_BYTES_PER_FUSE);
 120                 i += RK3399_BYTES_PER_FUSE;
 121         }
 122
 123         /* Switch to standby mode */
 124         writel(RK3399_PD | RK3399_CSB, &efuse->ctrl);
 125
 126         memcpy(buf, bytes + addr_offset, size);
 127
 128         return 0;
 129 }
 130
 131 static int rockchip_efuse_read(struct udevice *dev, int offset,
 132                                void *buf, int size)
 133 {
 134         return rockchip_rk3399_efuse_read(dev, offset, buf, size);
 135 }
 136
 137 static const struct misc_ops rockchip_efuse_ops = {
 138         .read = rockchip_efuse_read,
 139 };
 140
 141 static int rockchip_efuse_ofdata_to_platdata(struct udevice *dev)
 142 {
 143         struct rockchip_efuse_platdata *plat = dev_get_platdata(dev);
 144
 145         plat->base = (void *)dev_read_addr(dev);
 146         return 0;
 147 }
 148
 149 static const struct udevice_id rockchip_efuse_ids[] = {
 150         { .compatible = "rockchip,rk3399-efuse" },
 151         {}
 152 };
 153
 154 U_BOOT_DRIVER(rockchip_efuse) = {
 155         .name = "rockchip_efuse",
 156         .id = UCLASS_MISC,
 157         .of_match = rockchip_efuse_ids,
 158         .ofdata_to_platdata = rockchip_efuse_ofdata_to_platdata,
 159         .platdata_auto_alloc_size = sizeof(struct rockchip_efuse_platdata),
 160         .ops = &rockchip_efuse_ops,
 161 };