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Commit 072f1f91 authored by Rob Clark's avatar Rob Clark
Browse files

drm/msm: add support for "stolen" mem 



Add support to use the VRAM carveout (if specified in dtb) for fbdev
scanout buffer.  This allows drm/msm to take over a bootloader splash-
screen, and avoids corruption on screen that results if the kernel uses
memory that is still being scanned out for itself.

Signed-off-by: default avatarRob Clark <robdclark@gmail.com>
parent 5bf9c0b6

drivers/gpu/drm/msm/msm_drv.c

+40 −4
Original line number Diff line number Diff line
@@ -182,21 +182,57 @@ static int get_mdp_ver(struct platform_device *pdev) 
	return 4;

}



#include <linux/of_address.h>



static int msm_init_vram(struct drm_device *dev)

{

	struct msm_drm_private *priv = dev->dev_private;

	unsigned long size = 0;

	int ret = 0;



#ifdef CONFIG_OF

	/* In the device-tree world, we could have a 'memory-region'

	 * phandle, which gives us a link to our "vram".  Allocating

	 * is all nicely abstracted behind the dma api, but we need

	 * to know the entire size to allocate it all in one go. There

	 * are two cases:

	 *  1) device with no IOMMU, in which case we need exclusive

	 *     access to a VRAM carveout big enough for all gpu

	 *     buffers

	 *  2) device with IOMMU, but where the bootloader puts up

	 *     a splash screen.  In this case, the VRAM carveout

	 *     need only be large enough for fbdev fb.  But we need

	 *     exclusive access to the buffer to avoid the kernel

	 *     using those pages for other purposes (which appears

	 *     as corruption on screen before we have a chance to

	 *     load and do initial modeset)

	 */

	struct device_node *node;



	node = of_parse_phandle(dev->dev->of_node, "memory-region", 0);

	if (node) {

		struct resource r;

		ret = of_address_to_resource(node, 0, &r);

		if (ret)

			return ret;

		size = r.end - r.start;

		DRM_INFO("using VRAM carveout: %lx@%08x\n", size, r.start);

	} else

#endif



	/* if we have no IOMMU, then we need to use carveout allocator.

	 * Grab the entire CMA chunk carved out in early startup in

	 * mach-msm:

	 */

	if (!iommu_present(&platform_bus_type)) {

		DRM_INFO("using %s VRAM carveout\n", vram);

		size = memparse(vram, NULL);

	}



	if (size) {

		DEFINE_DMA_ATTRS(attrs);

		unsigned long size;

		void *p;



		DBG("using %s VRAM carveout", vram);

		size = memparse(vram, NULL);

		priv->vram.size = size;



		drm_mm_init(&priv->vram.mm, 0, (size >> PAGE_SHIFT) - 1);
@@ -220,7 +256,7 @@ static int msm_init_vram(struct drm_device *dev) 
				(uint32_t)(priv->vram.paddr + size));

	}



	return 0;

	return ret;

}



static int msm_load(struct drm_device *dev, unsigned long flags)

drivers/gpu/drm/msm/msm_fbdev.c

+2 −1
Original line number Diff line number Diff line
@@ -110,7 +110,8 @@ static int msm_fbdev_create(struct drm_fb_helper *helper, 
	size = mode_cmd.pitches[0] * mode_cmd.height;

	DBG("allocating %d bytes for fb %d", size, dev->primary->index);

	mutex_lock(&dev->struct_mutex);

	fbdev->bo = msm_gem_new(dev, size, MSM_BO_SCANOUT | MSM_BO_WC);

	fbdev->bo = msm_gem_new(dev, size, MSM_BO_SCANOUT |

			MSM_BO_WC | MSM_BO_STOLEN);

	mutex_unlock(&dev->struct_mutex);

	if (IS_ERR(fbdev->bo)) {

		ret = PTR_ERR(fbdev->bo);

drivers/gpu/drm/msm/msm_gem.c

+20 −5
Original line number Diff line number Diff line
@@ -32,6 +32,12 @@ static dma_addr_t physaddr(struct drm_gem_object *obj) 
			priv->vram.paddr;

}



static bool use_pages(struct drm_gem_object *obj)

{

	struct msm_gem_object *msm_obj = to_msm_bo(obj);

	return !msm_obj->vram_node;

}



/* allocate pages from VRAM carveout, used when no IOMMU: */

static struct page **get_pages_vram(struct drm_gem_object *obj,

		int npages)
@@ -72,7 +78,7 @@ static struct page **get_pages(struct drm_gem_object *obj) 
		struct page **p;

		int npages = obj->size >> PAGE_SHIFT;



		if (iommu_present(&platform_bus_type))

		if (use_pages(obj))

			p = drm_gem_get_pages(obj);

		else

			p = get_pages_vram(obj, npages);
@@ -116,7 +122,7 @@ static void put_pages(struct drm_gem_object *obj) 
		sg_free_table(msm_obj->sgt);

		kfree(msm_obj->sgt);



		if (iommu_present(&platform_bus_type))

		if (use_pages(obj))

			drm_gem_put_pages(obj, msm_obj->pages, true, false);

		else {

			drm_mm_remove_node(msm_obj->vram_node);
@@ -580,6 +586,7 @@ static int msm_gem_new_impl(struct drm_device *dev, 
	struct msm_drm_private *priv = dev->dev_private;

	struct msm_gem_object *msm_obj;

	unsigned sz;

	bool use_vram = false;



	switch (flags & MSM_BO_CACHE_MASK) {

	case MSM_BO_UNCACHED:
@@ -592,15 +599,23 @@ static int msm_gem_new_impl(struct drm_device *dev, 
		return -EINVAL;

	}



	sz = sizeof(*msm_obj);

	if (!iommu_present(&platform_bus_type))

		use_vram = true;

	else if ((flags & MSM_BO_STOLEN) && priv->vram.size)

		use_vram = true;



	if (WARN_ON(use_vram && !priv->vram.size))

		return -EINVAL;



	sz = sizeof(*msm_obj);

	if (use_vram)

		sz += sizeof(struct drm_mm_node);



	msm_obj = kzalloc(sz, GFP_KERNEL);

	if (!msm_obj)

		return -ENOMEM;



	if (!iommu_present(&platform_bus_type))

	if (use_vram)

		msm_obj->vram_node = (void *)&msm_obj[1];



	msm_obj->flags = flags;
@@ -630,7 +645,7 @@ struct drm_gem_object *msm_gem_new(struct drm_device *dev, 
	if (ret)

		goto fail;



	if (iommu_present(&platform_bus_type)) {

	if (use_pages(obj)) {

		ret = drm_gem_object_init(dev, obj, size);

		if (ret)

			goto fail;

drivers/gpu/drm/msm/msm_gem.h

+4 −1
Original line number Diff line number Diff line
@@ -21,6 +21,9 @@ 
#include <linux/reservation.h>

#include "msm_drv.h"



/* Additional internal-use only BO flags: */

#define MSM_BO_STOLEN        0x10000000    /* try to use stolen/splash memory */



struct msm_gem_object {

	struct drm_gem_object base;
@@ -59,7 +62,7 @@ struct msm_gem_object { 
	struct reservation_object _resv;



	/* For physically contiguous buffers.  Used when we don't have

	 * an IOMMU.

	 * an IOMMU.  Also used for stolen/splashscreen buffer.

	 */

	struct drm_mm_node *vram_node;

};