drivers/soc/mediatek/mtk-infracfg.c

   1 /*
   2  * Copyright (c) 2015 Pengutronix, Sascha Hauer <kernel@pengutronix.de>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/export.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/regmap.h>
  17 #include <linux/soc/mediatek/infracfg.h>
  18 #include <asm/processor.h>
  19
  20 #define INFRA_TOPAXI_PROTECTEN          0x0220
  21 #define INFRA_TOPAXI_PROTECTSTA1        0x0228
  22
  23 /**
  24  * mtk_infracfg_set_bus_protection - enable bus protection
  25  * @regmap: The infracfg regmap
  26  * @mask: The mask containing the protection bits to be enabled.
  27  *
  28  * This function enables the bus protection bits for disabled power
  29  * domains so that the system does not hang when some unit accesses the
  30  * bus while in power down.
  31  */
  32 int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask)
  33 {
  34         unsigned long expired;
  35         u32 val;
  36         int ret;
  37
  38         regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, mask);
  39
  40         expired = jiffies + HZ;
  41
  42         while (1) {
  43                 ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  44                 if (ret)
  45                         return ret;
  46
  47                 if ((val & mask) == mask)
  48                         break;
  49
  50                 cpu_relax();
  51                 if (time_after(jiffies, expired))
  52                         return -EIO;
  53         }
  54
  55         return 0;
  56 }
  57
  58 /**
  59  * mtk_infracfg_clear_bus_protection - disable bus protection
  60  * @regmap: The infracfg regmap
  61  * @mask: The mask containing the protection bits to be disabled.
  62  *
  63  * This function disables the bus protection bits previously enabled with
  64  * mtk_infracfg_set_bus_protection.
  65  */
  66 int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask)
  67 {
  68         unsigned long expired;
  69         int ret;
  70
  71         regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
  72
  73         expired = jiffies + HZ;
  74
  75         while (1) {
  76                 u32 val;
  77
  78                 ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  79                 if (ret)
  80                         return ret;
  81
  82                 if (!(val & mask))
  83                         break;
  84
  85                 cpu_relax();
  86                 if (time_after(jiffies, expired))
  87                         return -EIO;
  88         }
  89
  90         return 0;
  91 }