drivers/gpu/drm/rockchip/rockchip_drm_psr.c

   1 /*
   2  * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
   3  * Author: Yakir Yang <ykk@rock-chips.com>
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <drm/drmP.h>
  16 #include <drm/drm_crtc_helper.h>
  17
  18 #include "rockchip_drm_drv.h"
  19 #include "rockchip_drm_psr.h"
  20
  21 #define PSR_FLUSH_TIMEOUT_MS    100
  22
  23 struct psr_drv {
  24         struct list_head        list;
  25         struct drm_encoder      *encoder;
  26
  27         struct mutex            lock;
  28         int                     inhibit_count;
  29         bool                    enabled;
  30
  31         struct delayed_work     flush_work;
  32
  33         int (*set)(struct drm_encoder *encoder, bool enable);
  34 };
  35
  36 static struct psr_drv *find_psr_by_encoder(struct drm_encoder *encoder)
  37 {
  38         struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
  39         struct psr_drv *psr;
  40
  41         mutex_lock(&drm_drv->psr_list_lock);
  42         list_for_each_entry(psr, &drm_drv->psr_list, list) {
  43                 if (psr->encoder == encoder)
  44                         goto out;
  45         }
  46         psr = ERR_PTR(-ENODEV);
  47
  48 out:
  49         mutex_unlock(&drm_drv->psr_list_lock);
  50         return psr;
  51 }
  52
  53 static int psr_set_state_locked(struct psr_drv *psr, bool enable)
  54 {
  55         int ret;
  56
  57         if (psr->inhibit_count > 0)
  58                 return -EINVAL;
  59
  60         if (enable == psr->enabled)
  61                 return 0;
  62
  63         ret = psr->set(psr->encoder, enable);
  64         if (ret)
  65                 return ret;
  66
  67         psr->enabled = enable;
  68         return 0;
  69 }
  70
  71 static void psr_flush_handler(struct work_struct *work)
  72 {
  73         struct psr_drv *psr = container_of(to_delayed_work(work),
  74                                            struct psr_drv, flush_work);
  75
  76         mutex_lock(&psr->lock);
  77         psr_set_state_locked(psr, true);
  78         mutex_unlock(&psr->lock);
  79 }
  80
  81 /**
  82  * rockchip_drm_psr_inhibit_put - release PSR inhibit on given encoder
  83  * @encoder: encoder to obtain the PSR encoder
  84  *
  85  * Decrements PSR inhibit count on given encoder. Should be called only
  86  * for a PSR inhibit count increment done before. If PSR inhibit counter
  87  * reaches zero, PSR flush work is scheduled to make the hardware enter
  88  * PSR mode in PSR_FLUSH_TIMEOUT_MS.
  89  *
  90  * Returns:
  91  * Zero on success, negative errno on failure.
  92  */
  93 int rockchip_drm_psr_inhibit_put(struct drm_encoder *encoder)
  94 {
  95         struct psr_drv *psr = find_psr_by_encoder(encoder);
  96
  97         if (IS_ERR(psr))
  98                 return PTR_ERR(psr);
  99
 100         mutex_lock(&psr->lock);
 101         --psr->inhibit_count;
 102         WARN_ON(psr->inhibit_count < 0);
 103         if (!psr->inhibit_count)
 104                 mod_delayed_work(system_wq, &psr->flush_work,
 105                                  PSR_FLUSH_TIMEOUT_MS);
 106         mutex_unlock(&psr->lock);
 107
 108         return 0;
 109 }
 110 EXPORT_SYMBOL(rockchip_drm_psr_inhibit_put);
 111
 112 /**
 113  * rockchip_drm_psr_inhibit_get - acquire PSR inhibit on given encoder
 114  * @encoder: encoder to obtain the PSR encoder
 115  *
 116  * Increments PSR inhibit count on given encoder. This function guarantees
 117  * that after it returns PSR is turned off on given encoder and no PSR-related
 118  * hardware state change occurs at least until a matching call to
 119  * rockchip_drm_psr_inhibit_put() is done.
 120  *
 121  * Returns:
 122  * Zero on success, negative errno on failure.
 123  */
 124 int rockchip_drm_psr_inhibit_get(struct drm_encoder *encoder)
 125 {
 126         struct psr_drv *psr = find_psr_by_encoder(encoder);
 127
 128         if (IS_ERR(psr))
 129                 return PTR_ERR(psr);
 130
 131         mutex_lock(&psr->lock);
 132         psr_set_state_locked(psr, false);
 133         ++psr->inhibit_count;
 134         mutex_unlock(&psr->lock);
 135         cancel_delayed_work_sync(&psr->flush_work);
 136
 137         return 0;
 138 }
 139 EXPORT_SYMBOL(rockchip_drm_psr_inhibit_get);
 140
 141 static void rockchip_drm_do_flush(struct psr_drv *psr)
 142 {
 143         cancel_delayed_work_sync(&psr->flush_work);
 144
 145         mutex_lock(&psr->lock);
 146         if (!psr_set_state_locked(psr, false))
 147                 mod_delayed_work(system_wq, &psr->flush_work,
 148                                  PSR_FLUSH_TIMEOUT_MS);
 149         mutex_unlock(&psr->lock);
 150 }
 151
 152 /**
 153  * rockchip_drm_psr_flush_all - force to flush all registered PSR encoders
 154  * @dev: drm device
 155  *
 156  * Disable the PSR function for all registered encoders, and then enable the
 157  * PSR function back after PSR_FLUSH_TIMEOUT. If encoder PSR state have been
 158  * changed during flush time, then keep the state no change after flush
 159  * timeout.
 160  *
 161  * Returns:
 162  * Zero on success, negative errno on failure.
 163  */
 164 void rockchip_drm_psr_flush_all(struct drm_device *dev)
 165 {
 166         struct rockchip_drm_private *drm_drv = dev->dev_private;
 167         struct psr_drv *psr;
 168
 169         mutex_lock(&drm_drv->psr_list_lock);
 170         list_for_each_entry(psr, &drm_drv->psr_list, list)
 171                 rockchip_drm_do_flush(psr);
 172         mutex_unlock(&drm_drv->psr_list_lock);
 173 }
 174 EXPORT_SYMBOL(rockchip_drm_psr_flush_all);
 175
 176 /**
 177  * rockchip_drm_psr_register - register encoder to psr driver
 178  * @encoder: encoder that obtain the PSR function
 179  * @psr_set: call back to set PSR state
 180  *
 181  * The function returns with PSR inhibit counter initialized with one
 182  * and the caller (typically encoder driver) needs to call
 183  * rockchip_drm_psr_inhibit_put() when it becomes ready to accept PSR
 184  * enable request.
 185  *
 186  * Returns:
 187  * Zero on success, negative errno on failure.
 188  */
 189 int rockchip_drm_psr_register(struct drm_encoder *encoder,
 190                         int (*psr_set)(struct drm_encoder *, bool enable))
 191 {
 192         struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
 193         struct psr_drv *psr;
 194
 195         if (!encoder || !psr_set)
 196                 return -EINVAL;
 197
 198         psr = kzalloc(sizeof(struct psr_drv), GFP_KERNEL);
 199         if (!psr)
 200                 return -ENOMEM;
 201
 202         INIT_DELAYED_WORK(&psr->flush_work, psr_flush_handler);
 203         mutex_init(&psr->lock);
 204
 205         psr->inhibit_count = 1;
 206         psr->enabled = false;
 207         psr->encoder = encoder;
 208         psr->set = psr_set;
 209
 210         mutex_lock(&drm_drv->psr_list_lock);
 211         list_add_tail(&psr->list, &drm_drv->psr_list);
 212         mutex_unlock(&drm_drv->psr_list_lock);
 213
 214         return 0;
 215 }
 216 EXPORT_SYMBOL(rockchip_drm_psr_register);
 217
 218 /**
 219  * rockchip_drm_psr_unregister - unregister encoder to psr driver
 220  * @encoder: encoder that obtain the PSR function
 221  * @psr_set: call back to set PSR state
 222  *
 223  * It is expected that the PSR inhibit counter is 1 when this function is
 224  * called, which corresponds to a state when related encoder has been
 225  * disconnected from any CRTCs and its driver called
 226  * rockchip_drm_psr_inhibit_get() to stop the PSR logic.
 227  *
 228  * Returns:
 229  * Zero on success, negative errno on failure.
 230  */
 231 void rockchip_drm_psr_unregister(struct drm_encoder *encoder)
 232 {
 233         struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
 234         struct psr_drv *psr, *n;
 235
 236         mutex_lock(&drm_drv->psr_list_lock);
 237         list_for_each_entry_safe(psr, n, &drm_drv->psr_list, list) {
 238                 if (psr->encoder == encoder) {
 239                         /*
 240                          * Any other value would mean that the encoder
 241                          * is still in use.
 242                          */
 243                         WARN_ON(psr->inhibit_count != 1);
 244
 245                         list_del(&psr->list);
 246                         kfree(psr);
 247                 }
 248         }
 249         mutex_unlock(&drm_drv->psr_list_lock);
 250 }
 251 EXPORT_SYMBOL(rockchip_drm_psr_unregister);