drivers/gpu/drm/tinydrm/core/tinydrm-core.c

   1 /*
   2  * Copyright (C) 2016 Noralf Trønnes
   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 as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include <drm/drm_atomic.h>
  11 #include <drm/drm_atomic_helper.h>
  12 #include <drm/drm_crtc_helper.h>
  13 #include <drm/drm_fb_helper.h>
  14 #include <drm/drm_gem_framebuffer_helper.h>
  15 #include <drm/tinydrm/tinydrm.h>
  16 #include <linux/device.h>
  17 #include <linux/dma-buf.h>
  18
  19 /**
  20  * DOC: overview
  21  *
  22  * This library provides driver helpers for very simple display hardware.
  23  *
  24  * It is based on &drm_simple_display_pipe coupled with a &drm_connector which
  25  * has only one fixed &drm_display_mode. The framebuffers are backed by the
  26  * cma helper and have support for framebuffer flushing (dirty).
  27  * fbdev support is also included.
  28  *
  29  */
  30
  31 /**
  32  * DOC: core
  33  *
  34  * The driver allocates &tinydrm_device, initializes it using
  35  * devm_tinydrm_init(), sets up the pipeline using tinydrm_display_pipe_init()
  36  * and registers the DRM device using devm_tinydrm_register().
  37  */
  38
  39 /**
  40  * tinydrm_gem_cma_prime_import_sg_table - Produce a CMA GEM object from
  41  *     another driver's scatter/gather table of pinned pages
  42  * @drm: DRM device to import into
  43  * @attach: DMA-BUF attachment
  44  * @sgt: Scatter/gather table of pinned pages
  45  *
  46  * This function imports a scatter/gather table exported via DMA-BUF by
  47  * another driver using drm_gem_cma_prime_import_sg_table(). It sets the
  48  * kernel virtual address on the CMA object. Drivers should use this as their
  49  * &drm_driver->gem_prime_import_sg_table callback if they need the virtual
  50  * address. tinydrm_gem_cma_free_object() should be used in combination with
  51  * this function.
  52  *
  53  * Returns:
  54  * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
  55  * error code on failure.
  56  */
  57 struct drm_gem_object *
  58 tinydrm_gem_cma_prime_import_sg_table(struct drm_device *drm,
  59                                       struct dma_buf_attachment *attach,
  60                                       struct sg_table *sgt)
  61 {
  62         struct drm_gem_cma_object *cma_obj;
  63         struct drm_gem_object *obj;
  64         void *vaddr;
  65
  66         vaddr = dma_buf_vmap(attach->dmabuf);
  67         if (!vaddr) {
  68                 DRM_ERROR("Failed to vmap PRIME buffer\n");
  69                 return ERR_PTR(-ENOMEM);
  70         }
  71
  72         obj = drm_gem_cma_prime_import_sg_table(drm, attach, sgt);
  73         if (IS_ERR(obj)) {
  74                 dma_buf_vunmap(attach->dmabuf, vaddr);
  75                 return obj;
  76         }
  77
  78         cma_obj = to_drm_gem_cma_obj(obj);
  79         cma_obj->vaddr = vaddr;
  80
  81         return obj;
  82 }
  83 EXPORT_SYMBOL(tinydrm_gem_cma_prime_import_sg_table);
  84
  85 /**
  86  * tinydrm_gem_cma_free_object - Free resources associated with a CMA GEM
  87  *                               object
  88  * @gem_obj: GEM object to free
  89  *
  90  * This function frees the backing memory of the CMA GEM object, cleans up the
  91  * GEM object state and frees the memory used to store the object itself using
  92  * drm_gem_cma_free_object(). It also handles PRIME buffers which has the kernel
  93  * virtual address set by tinydrm_gem_cma_prime_import_sg_table(). Drivers
  94  * can use this as their &drm_driver->gem_free_object_unlocked callback.
  95  */
  96 void tinydrm_gem_cma_free_object(struct drm_gem_object *gem_obj)
  97 {
  98         if (gem_obj->import_attach) {
  99                 struct drm_gem_cma_object *cma_obj;
 100
 101                 cma_obj = to_drm_gem_cma_obj(gem_obj);
 102                 dma_buf_vunmap(gem_obj->import_attach->dmabuf, cma_obj->vaddr);
 103                 cma_obj->vaddr = NULL;
 104         }
 105
 106         drm_gem_cma_free_object(gem_obj);
 107 }
 108 EXPORT_SYMBOL_GPL(tinydrm_gem_cma_free_object);
 109
 110 static struct drm_framebuffer *
 111 tinydrm_fb_create(struct drm_device *drm, struct drm_file *file_priv,
 112                   const struct drm_mode_fb_cmd2 *mode_cmd)
 113 {
 114         struct tinydrm_device *tdev = drm->dev_private;
 115
 116         return drm_gem_fb_create_with_funcs(drm, file_priv, mode_cmd,
 117                                             tdev->fb_funcs);
 118 }
 119
 120 static const struct drm_mode_config_funcs tinydrm_mode_config_funcs = {
 121         .fb_create = tinydrm_fb_create,
 122         .atomic_check = drm_atomic_helper_check,
 123         .atomic_commit = drm_atomic_helper_commit,
 124 };
 125
 126 static int tinydrm_init(struct device *parent, struct tinydrm_device *tdev,
 127                         const struct drm_framebuffer_funcs *fb_funcs,
 128                         struct drm_driver *driver)
 129 {
 130         struct drm_device *drm;
 131
 132         mutex_init(&tdev->dirty_lock);
 133         tdev->fb_funcs = fb_funcs;
 134
 135         /*
 136          * We don't embed drm_device, because that prevent us from using
 137          * devm_kzalloc() to allocate tinydrm_device in the driver since
 138          * drm_dev_unref() frees the structure. The devm_ functions provide
 139          * for easy error handling.
 140          */
 141         drm = drm_dev_alloc(driver, parent);
 142         if (IS_ERR(drm))
 143                 return PTR_ERR(drm);
 144
 145         tdev->drm = drm;
 146         drm->dev_private = tdev;
 147         drm_mode_config_init(drm);
 148         drm->mode_config.funcs = &tinydrm_mode_config_funcs;
 149
 150         return 0;
 151 }
 152
 153 static void tinydrm_fini(struct tinydrm_device *tdev)
 154 {
 155         drm_mode_config_cleanup(tdev->drm);
 156         mutex_destroy(&tdev->dirty_lock);
 157         tdev->drm->dev_private = NULL;
 158         drm_dev_unref(tdev->drm);
 159 }
 160
 161 static void devm_tinydrm_release(void *data)
 162 {
 163         tinydrm_fini(data);
 164 }
 165
 166 /**
 167  * devm_tinydrm_init - Initialize tinydrm device
 168  * @parent: Parent device object
 169  * @tdev: tinydrm device
 170  * @fb_funcs: Framebuffer functions
 171  * @driver: DRM driver
 172  *
 173  * This function initializes @tdev, the underlying DRM device and it's
 174  * mode_config. Resources will be automatically freed on driver detach (devres)
 175  * using drm_mode_config_cleanup() and drm_dev_unref().
 176  *
 177  * Returns:
 178  * Zero on success, negative error code on failure.
 179  */
 180 int devm_tinydrm_init(struct device *parent, struct tinydrm_device *tdev,
 181                       const struct drm_framebuffer_funcs *fb_funcs,
 182                       struct drm_driver *driver)
 183 {
 184         int ret;
 185
 186         ret = tinydrm_init(parent, tdev, fb_funcs, driver);
 187         if (ret)
 188                 return ret;
 189
 190         ret = devm_add_action(parent, devm_tinydrm_release, tdev);
 191         if (ret)
 192                 tinydrm_fini(tdev);
 193
 194         return ret;
 195 }
 196 EXPORT_SYMBOL(devm_tinydrm_init);
 197
 198 static int tinydrm_register(struct tinydrm_device *tdev)
 199 {
 200         struct drm_device *drm = tdev->drm;
 201         int ret;
 202
 203         ret = drm_dev_register(tdev->drm, 0);
 204         if (ret)
 205                 return ret;
 206
 207         ret = drm_fbdev_generic_setup(drm, 0);
 208         if (ret)
 209                 DRM_ERROR("Failed to initialize fbdev: %d\n", ret);
 210
 211         return 0;
 212 }
 213
 214 static void tinydrm_unregister(struct tinydrm_device *tdev)
 215 {
 216         drm_atomic_helper_shutdown(tdev->drm);
 217         drm_dev_unregister(tdev->drm);
 218 }
 219
 220 static void devm_tinydrm_register_release(void *data)
 221 {
 222         tinydrm_unregister(data);
 223 }
 224
 225 /**
 226  * devm_tinydrm_register - Register tinydrm device
 227  * @tdev: tinydrm device
 228  *
 229  * This function registers the underlying DRM device and fbdev.
 230  * These resources will be automatically unregistered on driver detach (devres)
 231  * and the display pipeline will be disabled.
 232  *
 233  * Returns:
 234  * Zero on success, negative error code on failure.
 235  */
 236 int devm_tinydrm_register(struct tinydrm_device *tdev)
 237 {
 238         struct device *dev = tdev->drm->dev;
 239         int ret;
 240
 241         ret = tinydrm_register(tdev);
 242         if (ret)
 243                 return ret;
 244
 245         ret = devm_add_action(dev, devm_tinydrm_register_release, tdev);
 246         if (ret)
 247                 tinydrm_unregister(tdev);
 248
 249         return ret;
 250 }
 251 EXPORT_SYMBOL(devm_tinydrm_register);
 252
 253 /**
 254  * tinydrm_shutdown - Shutdown tinydrm
 255  * @tdev: tinydrm device
 256  *
 257  * This function makes sure that the display pipeline is disabled.
 258  * Used by drivers in their shutdown callback to turn off the display
 259  * on machine shutdown and reboot.
 260  */
 261 void tinydrm_shutdown(struct tinydrm_device *tdev)
 262 {
 263         drm_atomic_helper_shutdown(tdev->drm);
 264 }
 265 EXPORT_SYMBOL(tinydrm_shutdown);
 266
 267 MODULE_LICENSE("GPL");