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 struct rst_config {
  17         unsigned int modemr;    /* Mode Monitoring Register Offset */
  18 };
  19
  20 static const struct rst_config rcar_rst_gen1 __initconst = {
  21         .modemr = 0x20,
  22 };
  23
  24 static const struct rst_config rcar_rst_gen2 __initconst = {
  25         .modemr = 0x60,
  26 };
  27
  28 static const struct of_device_id rcar_rst_matches[] __initconst = {
  29         /* RZ/G is handled like R-Car Gen2 */
  30         { .compatible = "renesas,r8a7743-rst", .data = &rcar_rst_gen2 },
  31         { .compatible = "renesas,r8a7745-rst", .data = &rcar_rst_gen2 },
  32         /* R-Car Gen1 */
  33         { .compatible = "renesas,r8a7778-reset-wdt", .data = &rcar_rst_gen1 },
  34         { .compatible = "renesas,r8a7779-reset-wdt", .data = &rcar_rst_gen1 },
  35         /* R-Car Gen2 */
  36         { .compatible = "renesas,r8a7790-rst", .data = &rcar_rst_gen2 },
  37         { .compatible = "renesas,r8a7791-rst", .data = &rcar_rst_gen2 },
  38         { .compatible = "renesas,r8a7792-rst", .data = &rcar_rst_gen2 },
  39         { .compatible = "renesas,r8a7793-rst", .data = &rcar_rst_gen2 },
  40         { .compatible = "renesas,r8a7794-rst", .data = &rcar_rst_gen2 },
  41         /* R-Car Gen3 is handled like R-Car Gen2 */
  42         { .compatible = "renesas,r8a7795-rst", .data = &rcar_rst_gen2 },
  43         { .compatible = "renesas,r8a7796-rst", .data = &rcar_rst_gen2 },
  44         { /* sentinel */ }
  45 };
  46
  47 static void __iomem *rcar_rst_base __initdata;
  48 static u32 saved_mode __initdata;
  49
  50 static int __init rcar_rst_init(void)
  51 {
  52         const struct of_device_id *match;
  53         const struct rst_config *cfg;
  54         struct device_node *np;
  55         void __iomem *base;
  56         int error = 0;
  57
  58         np = of_find_matching_node_and_match(NULL, rcar_rst_matches, &match);
  59         if (!np)
  60                 return -ENODEV;
  61
  62         base = of_iomap(np, 0);
  63         if (!base) {
  64                 pr_warn("%s: Cannot map regs\n", np->full_name);
  65                 error = -ENOMEM;
  66                 goto out_put;
  67         }
  68
  69         rcar_rst_base = base;
  70         cfg = match->data;
  71         saved_mode = ioread32(base + cfg->modemr);
  72
  73         pr_debug("%s: MODE = 0x%08x\n", np->full_name, saved_mode);
  74
  75 out_put:
  76         of_node_put(np);
  77         return error;
  78 }
  79
  80 int __init rcar_rst_read_mode_pins(u32 *mode)
  81 {
  82         int error;
  83
  84         if (!rcar_rst_base) {
  85                 error = rcar_rst_init();
  86                 if (error)
  87                         return error;
  88         }
  89
  90         *mode = saved_mode;
  91         return 0;
  92 }