linux/drivers/gpu/drm/omapdrm/omap_fbdev.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
   4 * Author: Rob Clark <rob@ti.com>
   5 */
   6
   7#include <drm/drm_crtc.h>
   8#include <drm/drm_util.h>
   9#include <drm/drm_fb_helper.h>
  10#include <drm/drm_file.h>
  11#include <drm/drm_fourcc.h>
  12
  13#include "omap_drv.h"
  14
  15MODULE_PARM_DESC(ywrap, "Enable ywrap scrolling (omap44xx and later, default 'y')");
  16static bool ywrap_enabled = true;
  17module_param_named(ywrap, ywrap_enabled, bool, 0644);
  18
  19/*
  20 * fbdev funcs, to implement legacy fbdev interface on top of drm driver
  21 */
  22
  23#define to_omap_fbdev(x) container_of(x, struct omap_fbdev, base)
  24
  25struct omap_fbdev {
  26        struct drm_fb_helper base;
  27        struct drm_framebuffer *fb;
  28        struct drm_gem_object *bo;
  29        bool ywrap_enabled;
  30
  31        /* for deferred dmm roll when getting called in atomic ctx */
  32        struct work_struct work;
  33};
  34
  35static struct drm_fb_helper *get_fb(struct fb_info *fbi);
  36
  37static void pan_worker(struct work_struct *work)
  38{
  39        struct omap_fbdev *fbdev = container_of(work, struct omap_fbdev, work);
  40        struct fb_info *fbi = fbdev->base.fbdev;
  41        int npages;
  42
  43        /* DMM roll shifts in 4K pages: */
  44        npages = fbi->fix.line_length >> PAGE_SHIFT;
  45        omap_gem_roll(fbdev->bo, fbi->var.yoffset * npages);
  46}
  47
  48static int omap_fbdev_pan_display(struct fb_var_screeninfo *var,
  49                struct fb_info *fbi)
  50{
  51        struct drm_fb_helper *helper = get_fb(fbi);
  52        struct omap_fbdev *fbdev = to_omap_fbdev(helper);
  53
  54        if (!helper)
  55                goto fallback;
  56
  57        if (!fbdev->ywrap_enabled)
  58                goto fallback;
  59
  60        if (drm_can_sleep()) {
  61                pan_worker(&fbdev->work);
  62        } else {
  63                struct omap_drm_private *priv = helper->dev->dev_private;
  64                queue_work(priv->wq, &fbdev->work);
  65        }
  66
  67        return 0;
  68
  69fallback:
  70        return drm_fb_helper_pan_display(var, fbi);
  71}
  72
  73static const struct fb_ops omap_fb_ops = {
  74        .owner = THIS_MODULE,
  75
  76        .fb_check_var   = drm_fb_helper_check_var,
  77        .fb_set_par     = drm_fb_helper_set_par,
  78        .fb_setcmap     = drm_fb_helper_setcmap,
  79        .fb_blank       = drm_fb_helper_blank,
  80        .fb_pan_display = omap_fbdev_pan_display,
  81        .fb_ioctl       = drm_fb_helper_ioctl,
  82
  83        .fb_read = drm_fb_helper_sys_read,
  84        .fb_write = drm_fb_helper_sys_write,
  85        .fb_fillrect = drm_fb_helper_sys_fillrect,
  86        .fb_copyarea = drm_fb_helper_sys_copyarea,
  87        .fb_imageblit = drm_fb_helper_sys_imageblit,
  88};
  89
  90static int omap_fbdev_create(struct drm_fb_helper *helper,
  91                struct drm_fb_helper_surface_size *sizes)
  92{
  93        struct omap_fbdev *fbdev = to_omap_fbdev(helper);
  94        struct drm_device *dev = helper->dev;
  95        struct omap_drm_private *priv = dev->dev_private;
  96        struct drm_framebuffer *fb = NULL;
  97        union omap_gem_size gsize;
  98        struct fb_info *fbi = NULL;
  99        struct drm_mode_fb_cmd2 mode_cmd = {0};
 100        dma_addr_t dma_addr;
 101        int ret;
 102
 103        sizes->surface_bpp = 32;
 104        sizes->surface_depth = 24;
 105
 106        DBG("create fbdev: %dx%d@%d (%dx%d)", sizes->surface_width,
 107                        sizes->surface_height, sizes->surface_bpp,
 108                        sizes->fb_width, sizes->fb_height);
 109
 110        mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
 111                        sizes->surface_depth);
 112
 113        mode_cmd.width = sizes->surface_width;
 114        mode_cmd.height = sizes->surface_height;
 115
 116        mode_cmd.pitches[0] =
 117                        DIV_ROUND_UP(mode_cmd.width * sizes->surface_bpp, 8);
 118
 119        fbdev->ywrap_enabled = priv->has_dmm && ywrap_enabled;
 120        if (fbdev->ywrap_enabled) {
 121                /* need to align pitch to page size if using DMM scrolling */
 122                mode_cmd.pitches[0] = PAGE_ALIGN(mode_cmd.pitches[0]);
 123        }
 124
 125        /* allocate backing bo */
 126        gsize = (union omap_gem_size){
 127                .bytes = PAGE_ALIGN(mode_cmd.pitches[0] * mode_cmd.height),
 128        };
 129        DBG("allocating %d bytes for fb %d", gsize.bytes, dev->primary->index);
 130        fbdev->bo = omap_gem_new(dev, gsize, OMAP_BO_SCANOUT | OMAP_BO_WC);
 131        if (!fbdev->bo) {
 132                dev_err(dev->dev, "failed to allocate buffer object\n");
 133                ret = -ENOMEM;
 134                goto fail;
 135        }
 136
 137        fb = omap_framebuffer_init(dev, &mode_cmd, &fbdev->bo);
 138        if (IS_ERR(fb)) {
 139                dev_err(dev->dev, "failed to allocate fb\n");
 140                /* note: if fb creation failed, we can't rely on fb destroy
 141                 * to unref the bo:
 142                 */
 143                drm_gem_object_put(fbdev->bo);
 144                ret = PTR_ERR(fb);
 145                goto fail;
 146        }
 147
 148        /* note: this keeps the bo pinned.. which is perhaps not ideal,
 149         * but is needed as long as we use fb_mmap() to mmap to userspace
 150         * (since this happens using fix.smem_start).  Possibly we could
 151         * implement our own mmap using GEM mmap support to avoid this
 152         * (non-tiled buffer doesn't need to be pinned for fbcon to write
 153         * to it).  Then we just need to be sure that we are able to re-
 154         * pin it in case of an opps.
 155         */
 156        ret = omap_gem_pin(fbdev->bo, &dma_addr);
 157        if (ret) {
 158                dev_err(dev->dev, "could not pin framebuffer\n");
 159                ret = -ENOMEM;
 160                goto fail;
 161        }
 162
 163        fbi = drm_fb_helper_alloc_fbi(helper);
 164        if (IS_ERR(fbi)) {
 165                dev_err(dev->dev, "failed to allocate fb info\n");
 166                ret = PTR_ERR(fbi);
 167                goto fail;
 168        }
 169
 170        DBG("fbi=%p, dev=%p", fbi, dev);
 171
 172        fbdev->fb = fb;
 173        helper->fb = fb;
 174
 175        fbi->fbops = &omap_fb_ops;
 176
 177        drm_fb_helper_fill_info(fbi, helper, sizes);
 178
 179        dev->mode_config.fb_base = dma_addr;
 180
 181        fbi->screen_buffer = omap_gem_vaddr(fbdev->bo);
 182        fbi->screen_size = fbdev->bo->size;
 183        fbi->fix.smem_start = dma_addr;
 184        fbi->fix.smem_len = fbdev->bo->size;
 185
 186        /* if we have DMM, then we can use it for scrolling by just
 187         * shuffling pages around in DMM rather than doing sw blit.
 188         */
 189        if (fbdev->ywrap_enabled) {
 190                DRM_INFO("Enabling DMM ywrap scrolling\n");
 191                fbi->flags |= FBINFO_HWACCEL_YWRAP | FBINFO_READS_FAST;
 192                fbi->fix.ywrapstep = 1;
 193        }
 194
 195
 196        DBG("par=%p, %dx%d", fbi->par, fbi->var.xres, fbi->var.yres);
 197        DBG("allocated %dx%d fb", fbdev->fb->width, fbdev->fb->height);
 198
 199        return 0;
 200
 201fail:
 202
 203        if (ret) {
 204                if (fb)
 205                        drm_framebuffer_remove(fb);
 206        }
 207
 208        return ret;
 209}
 210
 211static const struct drm_fb_helper_funcs omap_fb_helper_funcs = {
 212        .fb_probe = omap_fbdev_create,
 213};
 214
 215static struct drm_fb_helper *get_fb(struct fb_info *fbi)
 216{
 217        if (!fbi || strcmp(fbi->fix.id, MODULE_NAME)) {
 218                /* these are not the fb's you're looking for */
 219                return NULL;
 220        }
 221        return fbi->par;
 222}
 223
 224/* initialize fbdev helper */
 225void omap_fbdev_init(struct drm_device *dev)
 226{
 227        struct omap_drm_private *priv = dev->dev_private;
 228        struct omap_fbdev *fbdev = NULL;
 229        struct drm_fb_helper *helper;
 230        int ret = 0;
 231
 232        if (!priv->num_pipes)
 233                return;
 234
 235        fbdev = kzalloc(sizeof(*fbdev), GFP_KERNEL);
 236        if (!fbdev)
 237                goto fail;
 238
 239        INIT_WORK(&fbdev->work, pan_worker);
 240
 241        helper = &fbdev->base;
 242
 243        drm_fb_helper_prepare(dev, helper, &omap_fb_helper_funcs);
 244
 245        ret = drm_fb_helper_init(dev, helper);
 246        if (ret)
 247                goto fail;
 248
 249        ret = drm_fb_helper_initial_config(helper, 32);
 250        if (ret)
 251                goto fini;
 252
 253        priv->fbdev = helper;
 254
 255        return;
 256
 257fini:
 258        drm_fb_helper_fini(helper);
 259fail:
 260        kfree(fbdev);
 261
 262        dev_warn(dev->dev, "omap_fbdev_init failed\n");
 263}
 264
 265void omap_fbdev_fini(struct drm_device *dev)
 266{
 267        struct omap_drm_private *priv = dev->dev_private;
 268        struct drm_fb_helper *helper = priv->fbdev;
 269        struct omap_fbdev *fbdev;
 270
 271        DBG();
 272
 273        if (!helper)
 274                return;
 275
 276        drm_fb_helper_unregister_fbi(helper);
 277
 278        drm_fb_helper_fini(helper);
 279
 280        fbdev = to_omap_fbdev(helper);
 281
 282        /* unpin the GEM object pinned in omap_fbdev_create() */
 283        if (fbdev->bo)
 284                omap_gem_unpin(fbdev->bo);
 285
 286        /* this will free the backing object */
 287        if (fbdev->fb)
 288                drm_framebuffer_remove(fbdev->fb);
 289
 290        kfree(fbdev);
 291
 292        priv->fbdev = NULL;
 293}
 294