Store the IOMMU mapping created by the device core of each Exynos DRM
sub-device and restore it when the Exynos DRM driver is unbound. This
fixes IOMMU initialization failure for the second time when a deferred
probe is triggered from the bind() callback of master's compound DRM
driver. This also fixes the following issue found using kmemleak
detector:
unreferenced object 0xc2137640 (size 64):
  comm "swapper/0", pid 1, jiffies 
4294937900 (age 3127.400s)
  hex dump (first 32 bytes):
    50 a3 14 c2 80 a2 14 c2 01 00 00 00 20 00 00 00  P........... ...
    00 10 00 00 00 80 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<
3acd268d>] arch_setup_dma_ops+0x4c/0x104
    [<
9f7d2cce>] of_dma_configure+0x19c/0x3a4
    [<
ba07704b>] really_probe+0xb0/0x47c
    [<
4f510e4f>] driver_probe_device+0x78/0x1c4
    [<
7481a0cf>] device_driver_attach+0x58/0x60
    [<
0ff8f5c1>] __driver_attach+0xb8/0x158
    [<
86006144>] bus_for_each_dev+0x74/0xb4
    [<
10159dca>] bus_add_driver+0x1c0/0x200
    [<
8a265265>] driver_register+0x74/0x108
    [<
e0f3451a>] exynos_drm_init+0xb0/0x134
    [<
db3fc7ba>] do_one_initcall+0x90/0x458
    [<
6da35917>] kernel_init_freeable+0x188/0x200
    [<
db3f74d4>] kernel_init+0x8/0x110
    [<
1f3cddf9>] ret_from_fork+0x14/0x20
    [<
8cd12507>] 0x0
unreferenced object 0xc214a280 (size 128):
  comm "swapper/0", pid 1, jiffies 
4294937900 (age 3127.400s)
  hex dump (first 32 bytes):
    00 a0 ec ed 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<
3acd268d>] arch_setup_dma_ops+0x4c/0x104
    [<
9f7d2cce>] of_dma_configure+0x19c/0x3a4
    [<
ba07704b>] really_probe+0xb0/0x47c
    [<
4f510e4f>] driver_probe_device+0x78/0x1c4
    [<
7481a0cf>] device_driver_attach+0x58/0x60
    [<
0ff8f5c1>] __driver_attach+0xb8/0x158
    [<
86006144>] bus_for_each_dev+0x74/0xb4
    [<
10159dca>] bus_add_driver+0x1c0/0x200
    [<
8a265265>] driver_register+0x74/0x108
    [<
e0f3451a>] exynos_drm_init+0xb0/0x134
    [<
db3fc7ba>] do_one_initcall+0x90/0x458
    [<
6da35917>] kernel_init_freeable+0x188/0x200
    [<
db3f74d4>] kernel_init+0x8/0x110
    [<
1f3cddf9>] ret_from_fork+0x14/0x20
    [<
8cd12507>] 0x0
unreferenced object 0xedeca000 (size 4096):
  comm "swapper/0", pid 1, jiffies 
4294937900 (age 3127.400s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<
3acd268d>] arch_setup_dma_ops+0x4c/0x104
    [<
9f7d2cce>] of_dma_configure+0x19c/0x3a4
    [<
ba07704b>] really_probe+0xb0/0x47c
    [<
4f510e4f>] driver_probe_device+0x78/0x1c4
    [<
7481a0cf>] device_driver_attach+0x58/0x60
    [<
0ff8f5c1>] __driver_attach+0xb8/0x158
    [<
86006144>] bus_for_each_dev+0x74/0xb4
    [<
10159dca>] bus_add_driver+0x1c0/0x200
    [<
8a265265>] driver_register+0x74/0x108
    [<
e0f3451a>] exynos_drm_init+0xb0/0x134
    [<
db3fc7ba>] do_one_initcall+0x90/0x458
    [<
6da35917>] kernel_init_freeable+0x188/0x200
    [<
db3f74d4>] kernel_init+0x8/0x110
    [<
1f3cddf9>] ret_from_fork+0x14/0x20
    [<
8cd12507>] 0x0
unreferenced object 0xc214a300 (size 128):
  comm "swapper/0", pid 1, jiffies 
4294937900 (age 3127.400s)
  hex dump (first 32 bytes):
    00 a3 14 c2 00 a3 14 c2 00 40 18 c2 00 80 18 c2  .........@......
    02 00 02 00 ad 4e ad de ff ff ff ff ff ff ff ff  .....N..........
  backtrace:
    [<
08cbd8bc>] iommu_domain_alloc+0x24/0x50
    [<
b835abee>] arm_iommu_create_mapping+0xe4/0x134
    [<
3acd268d>] arch_setup_dma_ops+0x4c/0x104
    [<
9f7d2cce>] of_dma_configure+0x19c/0x3a4
    [<
ba07704b>] really_probe+0xb0/0x47c
    [<
4f510e4f>] driver_probe_device+0x78/0x1c4
    [<
7481a0cf>] device_driver_attach+0x58/0x60
    [<
0ff8f5c1>] __driver_attach+0xb8/0x158
    [<
86006144>] bus_for_each_dev+0x74/0xb4
    [<
10159dca>] bus_add_driver+0x1c0/0x200
    [<
8a265265>] driver_register+0x74/0x108
    [<
e0f3451a>] exynos_drm_init+0xb0/0x134
    [<
db3fc7ba>] do_one_initcall+0x90/0x458
    [<
6da35917>] kernel_init_freeable+0x188/0x200
    [<
db3f74d4>] kernel_init+0x8/0x110
    [<
1f3cddf9>] ret_from_fork+0x14/0x20
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
 struct decon_context {
        struct device                   *dev;
        struct drm_device               *drm_dev;
+       void                            *dma_priv;
        struct exynos_drm_crtc          *crtc;
        struct exynos_drm_plane         planes[WINDOWS_NR];
        struct exynos_drm_plane_config  configs[WINDOWS_NR];
 
        decon_clear_channels(ctx->crtc);
 
-       return exynos_drm_register_dma(drm_dev, dev);
+       return exynos_drm_register_dma(drm_dev, dev, &ctx->dma_priv);
 }
 
 static void decon_unbind(struct device *dev, struct device *master, void *data)
        decon_atomic_disable(ctx->crtc);
 
        /* detach this sub driver from iommu mapping if supported. */
-       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev);
+       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev, &ctx->dma_priv);
 }
 
 static const struct component_ops decon_component_ops = {
 
 struct decon_context {
        struct device                   *dev;
        struct drm_device               *drm_dev;
+       void                            *dma_priv;
        struct exynos_drm_crtc          *crtc;
        struct exynos_drm_plane         planes[WINDOWS_NR];
        struct exynos_drm_plane_config  configs[WINDOWS_NR];
 
        decon_clear_channels(ctx->crtc);
 
-       return exynos_drm_register_dma(drm_dev, ctx->dev);
+       return exynos_drm_register_dma(drm_dev, ctx->dev, &ctx->dma_priv);
 }
 
 static void decon_ctx_remove(struct decon_context *ctx)
 {
        /* detach this sub driver from iommu mapping if supported. */
-       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev);
+       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev, &ctx->dma_priv);
 }
 
 static u32 decon_calc_clkdiv(struct decon_context *ctx,
 
  * mapping.
  */
 static int drm_iommu_attach_device(struct drm_device *drm_dev,
-                               struct device *subdrv_dev)
+                               struct device *subdrv_dev, void **dma_priv)
 {
        struct exynos_drm_private *priv = drm_dev->dev_private;
        int ret;
                return ret;
 
        if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
-               if (to_dma_iommu_mapping(subdrv_dev))
+               /*
+                * Keep the original DMA mapping of the sub-device and
+                * restore it on Exynos DRM detach, otherwise the DMA
+                * framework considers it as IOMMU-less during the next
+                * probe (in case of deferred probe or modular build)
+                */
+               *dma_priv = to_dma_iommu_mapping(subdrv_dev);
+               if (*dma_priv)
                        arm_iommu_detach_device(subdrv_dev);
 
                ret = arm_iommu_attach_device(subdrv_dev, priv->mapping);
  * mapping
  */
 static void drm_iommu_detach_device(struct drm_device *drm_dev,
-                               struct device *subdrv_dev)
+                                   struct device *subdrv_dev, void **dma_priv)
 {
        struct exynos_drm_private *priv = drm_dev->dev_private;
 
-       if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU))
+       if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)) {
                arm_iommu_detach_device(subdrv_dev);
-       else if (IS_ENABLED(CONFIG_IOMMU_DMA))
+               arm_iommu_attach_device(subdrv_dev, *dma_priv);
+       } else if (IS_ENABLED(CONFIG_IOMMU_DMA))
                iommu_detach_device(priv->mapping, subdrv_dev);
 
        clear_dma_max_seg_size(subdrv_dev);
 }
 
-int exynos_drm_register_dma(struct drm_device *drm, struct device *dev)
+int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
+                           void **dma_priv)
 {
        struct exynos_drm_private *priv = drm->dev_private;
 
                priv->mapping = mapping;
        }
 
-       return drm_iommu_attach_device(drm, dev);
+       return drm_iommu_attach_device(drm, dev, dma_priv);
 }
 
-void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev)
+void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
+                              void **dma_priv)
 {
        if (IS_ENABLED(CONFIG_EXYNOS_IOMMU))
-               drm_iommu_detach_device(drm, dev);
+               drm_iommu_detach_device(drm, dev, dma_priv);
 }
 
 void exynos_drm_cleanup_dma(struct drm_device *drm)
 
        return priv->mapping ? true : false;
 }
 
-int exynos_drm_register_dma(struct drm_device *drm, struct device *dev);
-void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev);
+int exynos_drm_register_dma(struct drm_device *drm, struct device *dev,
+                           void **dma_priv);
+void exynos_drm_unregister_dma(struct drm_device *drm, struct device *dev,
+                              void **dma_priv);
 void exynos_drm_cleanup_dma(struct drm_device *drm);
 
 #ifdef CONFIG_DRM_EXYNOS_DPI
 
 struct fimc_context {
        struct exynos_drm_ipp ipp;
        struct drm_device *drm_dev;
+       void            *dma_priv;
        struct device   *dev;
        struct exynos_drm_ipp_task      *task;
        struct exynos_drm_ipp_formats   *formats;
 
        ctx->drm_dev = drm_dev;
        ipp->drm_dev = drm_dev;
-       exynos_drm_register_dma(drm_dev, dev);
+       exynos_drm_register_dma(drm_dev, dev, &ctx->dma_priv);
 
        exynos_drm_ipp_register(dev, ipp, &ipp_funcs,
                        DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |
        struct exynos_drm_ipp *ipp = &ctx->ipp;
 
        exynos_drm_ipp_unregister(dev, ipp);
-       exynos_drm_unregister_dma(drm_dev, dev);
+       exynos_drm_unregister_dma(drm_dev, dev, &ctx->dma_priv);
 }
 
 static const struct component_ops fimc_component_ops = {
 
 struct fimd_context {
        struct device                   *dev;
        struct drm_device               *drm_dev;
+       void                            *dma_priv;
        struct exynos_drm_crtc          *crtc;
        struct exynos_drm_plane         planes[WINDOWS_NR];
        struct exynos_drm_plane_config  configs[WINDOWS_NR];
        if (is_drm_iommu_supported(drm_dev))
                fimd_clear_channels(ctx->crtc);
 
-       return exynos_drm_register_dma(drm_dev, dev);
+       return exynos_drm_register_dma(drm_dev, dev, &ctx->dma_priv);
 }
 
 static void fimd_unbind(struct device *dev, struct device *master,
 
        fimd_atomic_disable(ctx->crtc);
 
-       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev);
+       exynos_drm_unregister_dma(ctx->drm_dev, ctx->dev, &ctx->dma_priv);
 
        if (ctx->encoder)
                exynos_dpi_remove(ctx->encoder);
 
 
 struct g2d_data {
        struct device                   *dev;
+       void                            *dma_priv;
        struct clk                      *gate_clk;
        void __iomem                    *regs;
        int                             irq;
                return ret;
        }
 
-       ret = exynos_drm_register_dma(drm_dev, dev);
+       ret = exynos_drm_register_dma(drm_dev, dev, &g2d->dma_priv);
        if (ret < 0) {
                dev_err(dev, "failed to enable iommu.\n");
                g2d_fini_cmdlist(g2d);
        priv->g2d_dev = NULL;
 
        cancel_work_sync(&g2d->runqueue_work);
-       exynos_drm_unregister_dma(g2d->drm_dev, dev);
+       exynos_drm_unregister_dma(g2d->drm_dev, dev, &g2d->dma_priv);
 }
 
 static const struct component_ops g2d_component_ops = {
 
 struct gsc_context {
        struct exynos_drm_ipp ipp;
        struct drm_device *drm_dev;
+       void            *dma_priv;
        struct device   *dev;
        struct exynos_drm_ipp_task      *task;
        struct exynos_drm_ipp_formats   *formats;
 
        ctx->drm_dev = drm_dev;
        ctx->drm_dev = drm_dev;
-       exynos_drm_register_dma(drm_dev, dev);
+       exynos_drm_register_dma(drm_dev, dev, &ctx->dma_priv);
 
        exynos_drm_ipp_register(dev, ipp, &ipp_funcs,
                        DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |
        struct exynos_drm_ipp *ipp = &ctx->ipp;
 
        exynos_drm_ipp_unregister(dev, ipp);
-       exynos_drm_unregister_dma(drm_dev, dev);
+       exynos_drm_unregister_dma(drm_dev, dev, &ctx->dma_priv);
 }
 
 static const struct component_ops gsc_component_ops = {
 
 struct rot_context {
        struct exynos_drm_ipp ipp;
        struct drm_device *drm_dev;
+       void            *dma_priv;
        struct device   *dev;
        void __iomem    *regs;
        struct clk      *clock;
 
        rot->drm_dev = drm_dev;
        ipp->drm_dev = drm_dev;
-       exynos_drm_register_dma(drm_dev, dev);
+       exynos_drm_register_dma(drm_dev, dev, &rot->dma_priv);
 
        exynos_drm_ipp_register(dev, ipp, &ipp_funcs,
                           DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE,
        struct exynos_drm_ipp *ipp = &rot->ipp;
 
        exynos_drm_ipp_unregister(dev, ipp);
-       exynos_drm_unregister_dma(rot->drm_dev, rot->dev);
+       exynos_drm_unregister_dma(rot->drm_dev, rot->dev, &rot->dma_priv);
 }
 
 static const struct component_ops rotator_component_ops = {
 
 struct scaler_context {
        struct exynos_drm_ipp           ipp;
        struct drm_device               *drm_dev;
+       void                            *dma_priv;
        struct device                   *dev;
        void __iomem                    *regs;
        struct clk                      *clock[SCALER_MAX_CLK];
 
        scaler->drm_dev = drm_dev;
        ipp->drm_dev = drm_dev;
-       exynos_drm_register_dma(drm_dev, dev);
+       exynos_drm_register_dma(drm_dev, dev, &scaler->dma_priv);
 
        exynos_drm_ipp_register(dev, ipp, &ipp_funcs,
                        DRM_EXYNOS_IPP_CAP_CROP | DRM_EXYNOS_IPP_CAP_ROTATE |
        struct exynos_drm_ipp *ipp = &scaler->ipp;
 
        exynos_drm_ipp_unregister(dev, ipp);
-       exynos_drm_unregister_dma(scaler->drm_dev, scaler->dev);
+       exynos_drm_unregister_dma(scaler->drm_dev, scaler->dev,
+                                 &scaler->dma_priv);
 }
 
 static const struct component_ops scaler_component_ops = {
 
        struct platform_device *pdev;
        struct device           *dev;
        struct drm_device       *drm_dev;
+       void                    *dma_priv;
        struct exynos_drm_crtc  *crtc;
        struct exynos_drm_plane planes[MIXER_WIN_NR];
        unsigned long           flags;
                }
        }
 
-       return exynos_drm_register_dma(drm_dev, mixer_ctx->dev);
+       return exynos_drm_register_dma(drm_dev, mixer_ctx->dev,
+                                      &mixer_ctx->dma_priv);
 }
 
 static void mixer_ctx_remove(struct mixer_context *mixer_ctx)
 {
-       exynos_drm_unregister_dma(mixer_ctx->drm_dev, mixer_ctx->dev);
+       exynos_drm_unregister_dma(mixer_ctx->drm_dev, mixer_ctx->dev,
+                                 &mixer_ctx->dma_priv);
 }
 
 static int mixer_enable_vblank(struct exynos_drm_crtc *crtc)