| Sascha Hauer | 16a624a | 2015-06-24 08:17:02 +0200 | [diff] [blame] | 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 | } |