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 #define INFRA_TOPAXI_PROTECTEN_SET      0x0260
  23 #define INFRA_TOPAXI_PROTECTEN_CLR      0x0264
  24
  25 /**
  26  * mtk_infracfg_set_bus_protection - enable bus protection
  27  * @regmap: The infracfg regmap
  28  * @mask: The mask containing the protection bits to be enabled.
  29  * @reg_update: The boolean flag determines to set the protection bits
  30  *              by regmap_update_bits with enable register(PROTECTEN) or
  31  *              by regmap_write with set register(PROTECTEN_SET).
  32  *
  33  * This function enables the bus protection bits for disabled power
  34  * domains so that the system does not hang when some unit accesses the
  35  * bus while in power down.
  36  */
  37 int mtk_infracfg_set_bus_protection(struct regmap *infracfg, u32 mask,
  38                 bool reg_update)
  39 {
  40         unsigned long expired;
  41         u32 val;
  42         int ret;
  43
  44         if (reg_update)
  45                 regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask,
  46                                 mask);
  47         else
  48                 regmap_write(infracfg, INFRA_TOPAXI_PROTECTEN_SET, mask);
  49
  50         expired = jiffies + HZ;
  51
  52         while (1) {
  53                 ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  54                 if (ret)
  55                         return ret;
  56
  57                 if ((val & mask) == mask)
  58                         break;
  59
  60                 cpu_relax();
  61                 if (time_after(jiffies, expired))
  62                         return -EIO;
  63         }
  64
  65         return 0;
  66 }
  67
  68 /**
  69  * mtk_infracfg_clear_bus_protection - disable bus protection
  70  * @regmap: The infracfg regmap
  71  * @mask: The mask containing the protection bits to be disabled.
  72  * @reg_update: The boolean flag determines to clear the protection bits
  73  *              by regmap_update_bits with enable register(PROTECTEN) or
  74  *              by regmap_write with clear register(PROTECTEN_CLR).
  75  *
  76  * This function disables the bus protection bits previously enabled with
  77  * mtk_infracfg_set_bus_protection.
  78  */
  79
  80 int mtk_infracfg_clear_bus_protection(struct regmap *infracfg, u32 mask,
  81                 bool reg_update)
  82 {
  83         unsigned long expired;
  84         int ret;
  85
  86         if (reg_update)
  87                 regmap_update_bits(infracfg, INFRA_TOPAXI_PROTECTEN, mask, 0);
  88         else
  89                 regmap_write(infracfg, INFRA_TOPAXI_PROTECTEN_CLR, mask);
  90
  91         expired = jiffies + HZ;
  92
  93         while (1) {
  94                 u32 val;
  95
  96                 ret = regmap_read(infracfg, INFRA_TOPAXI_PROTECTSTA1, &val);
  97                 if (ret)
  98                         return ret;
  99
 100                 if (!(val & mask))
 101                         break;
 102
 103                 cpu_relax();
 104                 if (time_after(jiffies, expired))
 105                         return -EIO;
 106         }
 107
 108         return 0;
 109 }