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 } 110