Oleg Perelet | b906a19 | 2017-01-04 09:50:02 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved. |
| 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 and |
| 6 | * only version 2 as 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/devfreq.h> |
| 15 | #include <linux/module.h> |
| 16 | #include "governor.h" |
| 17 | |
| 18 | unsigned long (*extern_get_bw)(void) = NULL; |
| 19 | unsigned long *dev_ab; |
| 20 | static unsigned long dev_ib; |
| 21 | |
| 22 | DEFINE_MUTEX(df_lock); |
| 23 | static struct devfreq *df; |
| 24 | |
| 25 | /* |
| 26 | * This function is 'get_target_freq' API for the governor. |
| 27 | * It just calls an external function that should be registered |
| 28 | * by KGSL driver to get and return a value for frequency. |
| 29 | */ |
| 30 | static int devfreq_vbif_get_freq(struct devfreq *df, |
| 31 | unsigned long *freq) |
| 32 | { |
| 33 | /* If the IB isn't set yet, check if it should be non-zero. */ |
| 34 | if (!dev_ib && extern_get_bw) { |
| 35 | dev_ib = extern_get_bw(); |
| 36 | if (dev_ab) |
| 37 | *dev_ab = dev_ib / 4; |
| 38 | } |
| 39 | |
| 40 | *freq = dev_ib; |
| 41 | return 0; |
| 42 | } |
| 43 | |
| 44 | /* |
| 45 | * Registers a function to be used to request a frequency |
| 46 | * value from legacy vbif based bus bandwidth governor. |
| 47 | * This function is called by KGSL driver. |
| 48 | */ |
| 49 | void devfreq_vbif_register_callback(void *p) |
| 50 | { |
| 51 | extern_get_bw = p; |
| 52 | } |
| 53 | |
| 54 | int devfreq_vbif_update_bw(unsigned long ib, unsigned long ab) |
| 55 | { |
| 56 | int ret = 0; |
| 57 | |
| 58 | mutex_lock(&df_lock); |
| 59 | if (df) { |
| 60 | mutex_lock(&df->lock); |
| 61 | dev_ib = ib; |
| 62 | *dev_ab = ab; |
| 63 | ret = update_devfreq(df); |
| 64 | mutex_unlock(&df->lock); |
| 65 | } |
| 66 | mutex_unlock(&df_lock); |
| 67 | return ret; |
| 68 | } |
| 69 | |
| 70 | static int devfreq_vbif_ev_handler(struct devfreq *devfreq, |
| 71 | unsigned int event, void *data) |
| 72 | { |
| 73 | int ret; |
| 74 | struct devfreq_dev_status stat; |
| 75 | |
| 76 | switch (event) { |
| 77 | case DEVFREQ_GOV_START: |
| 78 | mutex_lock(&df_lock); |
| 79 | df = devfreq; |
| 80 | if (df->profile->get_dev_status && |
| 81 | !df->profile->get_dev_status(df->dev.parent, &stat) && |
| 82 | stat.private_data) |
| 83 | dev_ab = stat.private_data; |
| 84 | else |
| 85 | pr_warn("Device doesn't take AB votes!\n"); |
| 86 | |
| 87 | mutex_unlock(&df_lock); |
| 88 | |
| 89 | ret = devfreq_vbif_update_bw(0, 0); |
| 90 | if (ret) { |
| 91 | pr_err("Unable to update BW! Gov start failed!\n"); |
| 92 | return ret; |
| 93 | } |
| 94 | /* |
| 95 | * Normally at this point governors start the polling with |
| 96 | * devfreq_monitor_start(df); |
| 97 | * This governor doesn't poll, but expect external calls |
| 98 | * of its devfreq_vbif_update_bw() function |
| 99 | */ |
| 100 | pr_debug("Enabled MSM VBIF governor\n"); |
| 101 | break; |
| 102 | |
| 103 | case DEVFREQ_GOV_STOP: |
| 104 | mutex_lock(&df_lock); |
| 105 | df = NULL; |
| 106 | mutex_unlock(&df_lock); |
| 107 | |
| 108 | pr_debug("Disabled MSM VBIF governor\n"); |
| 109 | break; |
| 110 | } |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | static struct devfreq_governor devfreq_vbif = { |
| 116 | .name = "bw_vbif", |
| 117 | .get_target_freq = devfreq_vbif_get_freq, |
| 118 | .event_handler = devfreq_vbif_ev_handler, |
| 119 | }; |
| 120 | |
| 121 | static int __init devfreq_vbif_init(void) |
| 122 | { |
| 123 | return devfreq_add_governor(&devfreq_vbif); |
| 124 | } |
| 125 | subsys_initcall(devfreq_vbif_init); |
| 126 | |
| 127 | static void __exit devfreq_vbif_exit(void) |
| 128 | { |
| 129 | int ret; |
| 130 | |
| 131 | ret = devfreq_remove_governor(&devfreq_vbif); |
| 132 | if (ret) |
| 133 | pr_err("%s: failed remove governor %d\n", __func__, ret); |
| 134 | |
| 135 | } |
| 136 | module_exit(devfreq_vbif_exit); |
| 137 | |
| 138 | MODULE_DESCRIPTION("VBIF based GPU bus BW voting governor"); |
| 139 | MODULE_LICENSE("GPL v2"); |
| 140 | |
| 141 | |