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: Rob Clark <robdclark@xxxxxxxxx>
---
drivers/gpu/drm/msm/msm_drv.c | 44 +++++++++++++++++++++++++++++++++++++----
drivers/gpu/drm/msm/msm_fbdev.c | 3 ++-
drivers/gpu/drm/msm/msm_gem.c | 25 ++++++++++++++++++-----
drivers/gpu/drm/msm/msm_gem.h | 5 ++++-
4 files changed, 66 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index b250610..0c38f34 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -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)
diff --git a/drivers/gpu/drm/msm/msm_fbdev.c b/drivers/gpu/drm/msm/msm_fbdev.c
index df60f65..95f6532 100644
--- a/drivers/gpu/drm/msm/msm_fbdev.c
+++ b/drivers/gpu/drm/msm/msm_fbdev.c
@@ -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);
diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
index 49dea4f..479d8af 100644
--- a/drivers/gpu/drm/msm/msm_gem.c
+++ b/drivers/gpu/drm/msm/msm_gem.c
@@ -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;
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index 8fbbd05..85d481e 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -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;
};
--
2.1.0
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