drm/exynos: add iommu support for hdmi driver

Changelog v2:
move iommu support feature to mixer side.
And below is Prathyush's comment.

According to the new IOMMU framework for exynos sysmmus,
the owner of the sysmmu-tv is mixer (which is the actual
device that does DMA) and not hdmi.
The mmu-master in sysmmu-tv node is set as below in exynos5250.dtsi
	sysmmu-tv {
		-
		mmu-master = <&mixer>;
	};

Changelog v1:
The iommu will be enabled when hdmi sub driver is probed and
will be disabled when removed.
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_hdmi.c

@@ -346,9 +346,23 @@ static int hdmi_subdrv_probe(struct drm_device *drm_dev,
 	ctx->hdmi_ctx->drm_dev = drm_dev;
 	ctx->mixer_ctx->drm_dev = drm_dev;
 
+	if (mixer_ops->iommu_on)
+		mixer_ops->iommu_on(ctx->mixer_ctx->ctx, true);
+
 	return 0;
 }
 
+static void hdmi_subdrv_remove(struct drm_device *drm_dev, struct device *dev)
+{
+	struct drm_hdmi_context *ctx;
+	struct exynos_drm_subdrv *subdrv = to_subdrv(dev);
+
+	ctx = get_ctx_from_subdrv(subdrv);
+
+	if (mixer_ops->iommu_on)
+		mixer_ops->iommu_on(ctx->mixer_ctx->ctx, false);
+}
+
 static int __devinit exynos_drm_hdmi_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -368,6 +382,7 @@ static int __devinit exynos_drm_hdmi_probe(struct platform_device *pdev)
 	subdrv->dev = dev;
 	subdrv->manager = &hdmi_manager;
 	subdrv->probe = hdmi_subdrv_probe;
+	subdrv->remove = hdmi_subdrv_remove;
 
 	platform_set_drvdata(pdev, subdrv);
 

drivers/gpu/drm/exynos/exynos_drm_hdmi.h

@@ -62,6 +62,7 @@ struct exynos_hdmi_ops {
 
 struct exynos_mixer_ops {
 	/* manager */
+	int (*iommu_on)(void *ctx, bool enable);
 	int (*enable_vblank)(void *ctx, int pipe);
 	void (*disable_vblank)(void *ctx);
 	void (*dpms)(void *ctx, int mode);

drivers/gpu/drm/exynos/exynos_hdmi.c

@@ -74,6 +74,7 @@ struct hdmi_context {
 	struct mutex			hdmi_mutex;
 
 	void __iomem			*regs;
+	void				*parent_ctx;
 	int				external_irq;
 	int				internal_irq;
 
@@ -84,7 +85,6 @@ struct hdmi_context {
 	int cur_conf;
 
 	struct hdmi_resources		res;
-	void				*parent_ctx;
 
 	int				hpd_gpio;
 

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -36,6 +36,7 @@
 
 #include "exynos_drm_drv.h"
 #include "exynos_drm_hdmi.h"
+#include "exynos_drm_iommu.h"
 
 #define get_mixer_context(dev)	platform_get_drvdata(to_platform_device(dev))
 
@@ -80,6 +81,7 @@ enum mixer_version_id {
 
 struct mixer_context {
 	struct device		*dev;
+	struct drm_device	*drm_dev;
 	int			pipe;
 	bool			interlace;
 	bool			powered;
@@ -90,6 +92,7 @@ struct mixer_context {
 	struct mixer_resources	mixer_res;
 	struct hdmi_win_data	win_data[MIXER_WIN_NR];
 	enum mixer_version_id	mxr_ver;
+	void			*parent_ctx;
 };
 
 struct mixer_drv_data {
@@ -665,6 +668,24 @@ static void mixer_win_reset(struct mixer_context *ctx)
 	spin_unlock_irqrestore(&res->reg_slock, flags);
 }
 
+static int mixer_iommu_on(void *ctx, bool enable)
+{
+	struct exynos_drm_hdmi_context *drm_hdmi_ctx;
+	struct mixer_context *mdata = ctx;
+	struct drm_device *drm_dev;
+
+	drm_hdmi_ctx = mdata->parent_ctx;
+	drm_dev = drm_hdmi_ctx->drm_dev;
+
+	if (is_drm_iommu_supported(drm_dev)) {
+		if (enable)
+			return drm_iommu_attach_device(drm_dev, mdata->dev);
+
+		drm_iommu_detach_device(drm_dev, mdata->dev);
+	}
+	return 0;
+}
+
 static void mixer_poweron(struct mixer_context *ctx)
 {
 	struct mixer_resources *res = &ctx->mixer_res;
@@ -866,6 +887,7 @@ static void mixer_win_disable(void *ctx, int win)
 
 static struct exynos_mixer_ops mixer_ops = {
 	/* manager */
+	.iommu_on		= mixer_iommu_on,
 	.enable_vblank		= mixer_enable_vblank,
 	.disable_vblank		= mixer_disable_vblank,
 	.dpms			= mixer_dpms,
@@ -1140,6 +1162,7 @@ static int __devinit mixer_probe(struct platform_device *pdev)
 	}
 
 	ctx->dev = &pdev->dev;
+	ctx->parent_ctx = (void *)drm_hdmi_ctx;
 	drm_hdmi_ctx->ctx = (void *)ctx;
 	ctx->vp_enabled = drv->is_vp_enabled;
 	ctx->mxr_ver = drv->version;