drivers/soc/renesas/rcar-rst.c

   1 /*
   2  * R-Car Gen1 RESET/WDT, R-Car Gen2, Gen3, and RZ/G RST Driver
   3  *
   4  * Copyright (C) 2016 Glider bvba
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License.  See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #include <linux/err.h>
  12 #include <linux/io.h>
  13 #include <linux/of_address.h>
  14 #include <linux/soc/renesas/rcar-rst.h>
  15
  16 #define WDTRSTCR_RESET          0xA55A0002
  17 #define WDTRSTCR                0x0054
  18
  19 static int rcar_rst_enable_wdt_reset(void __iomem *base)
  20 {
  21         iowrite32(WDTRSTCR_RESET, base + WDTRSTCR);
  22         return 0;
  23 }
  24
  25 struct rst_config {
  26         unsigned int modemr;            /* Mode Monitoring Register Offset */
  27         int (*configure)(void *base);   /* Platform specific configuration */
  28 };
  29
  30 static const struct rst_config rcar_rst_gen1 __initconst = {
  31         .modemr = 0x20,
  32 };
  33
  34 static const struct rst_config rcar_rst_gen2 __initconst = {
  35         .modemr = 0x60,
  36         .configure = rcar_rst_enable_wdt_reset,
  37 };
  38
  39 static const struct rst_config rcar_rst_gen3 __initconst = {
  40         .modemr = 0x60,
  41 };
  42
  43 static const struct of_device_id rcar_rst_matches[] __initconst = {
  44         /* RZ/G is handled like R-Car Gen2 */
  45         { .compatible = "renesas,r8a7743-rst", .data = &rcar_rst_gen2 },
  46         { .compatible = "renesas,r8a7745-rst", .data = &rcar_rst_gen2 },
  47         { .compatible = "renesas,r8a77470-rst", .data = &rcar_rst_gen2 },
  48         /* R-Car Gen1 */
  49         { .compatible = "renesas,r8a7778-reset-wdt", .data = &rcar_rst_gen1 },
  50         { .compatible = "renesas,r8a7779-reset-wdt", .data = &rcar_rst_gen1 },
  51         /* R-Car Gen2 */
  52         { .compatible = "renesas,r8a7790-rst", .data = &rcar_rst_gen2 },
  53         { .compatible = "renesas,r8a7791-rst", .data = &rcar_rst_gen2 },
  54         { .compatible = "renesas,r8a7792-rst", .data = &rcar_rst_gen2 },
  55         { .compatible = "renesas,r8a7793-rst", .data = &rcar_rst_gen2 },
  56         { .compatible = "renesas,r8a7794-rst", .data = &rcar_rst_gen2 },
  57         /* R-Car Gen3 */
  58         { .compatible = "renesas,r8a7795-rst", .data = &rcar_rst_gen3 },
  59         { .compatible = "renesas,r8a7796-rst", .data = &rcar_rst_gen3 },
  60         { .compatible = "renesas,r8a77965-rst", .data = &rcar_rst_gen3 },
  61         { .compatible = "renesas,r8a77970-rst", .data = &rcar_rst_gen3 },
  62         { .compatible = "renesas,r8a77980-rst", .data = &rcar_rst_gen3 },
  63         { .compatible = "renesas,r8a77990-rst", .data = &rcar_rst_gen3 },
  64         { .compatible = "renesas,r8a77995-rst", .data = &rcar_rst_gen3 },
  65         { /* sentinel */ }
  66 };
  67
  68 static void __iomem *rcar_rst_base __initdata;
  69 static u32 saved_mode __initdata;
  70
  71 static int __init rcar_rst_init(void)
  72 {
  73         const struct of_device_id *match;
  74         const struct rst_config *cfg;
  75         struct device_node *np;
  76         void __iomem *base;
  77         int error = 0;
  78
  79         np = of_find_matching_node_and_match(NULL, rcar_rst_matches, &match);
  80         if (!np)
  81                 return -ENODEV;
  82
  83         base = of_iomap(np, 0);
  84         if (!base) {
  85                 pr_warn("%pOF: Cannot map regs\n", np);
  86                 error = -ENOMEM;
  87                 goto out_put;
  88         }
  89
  90         rcar_rst_base = base;
  91         cfg = match->data;
  92         saved_mode = ioread32(base + cfg->modemr);
  93         if (cfg->configure) {
  94                 error = cfg->configure(base);
  95                 if (error) {
  96                         pr_warn("%pOF: Cannot run SoC specific configuration\n",
  97                                 np);
  98                         goto out_put;
  99                 }
 100         }
 101
 102         pr_debug("%pOF: MODE = 0x%08x\n", np, saved_mode);
 103
 104 out_put:
 105         of_node_put(np);
 106         return error;
 107 }
 108
 109 int __init rcar_rst_read_mode_pins(u32 *mode)
 110 {
 111         int error;
 112
 113         if (!rcar_rst_base) {
 114                 error = rcar_rst_init();
 115                 if (error)
 116                         return error;
 117         }
 118
 119         *mode = saved_mode;
 120         return 0;
 121 }