drm/msm: add support for non-IOMMU systems

Add a VRAM carveout that is used for systems which do not have an IOMMU.

The VRAM carveout uses CMA.  The arch code must setup a CMA pool for the
device (preferrably in highmem.. a 256m-512m VRAM pool in lowmem is not
cool).  The user can configure the VRAM pool size using msm.vram module
param.

Technically, the abstraction of IOMMU behind msm_mmu is not strictly
needed, but it simplifies the GEM code a bit, and will be useful later
when I add support for a2xx devices with GPUMMU, so I decided to keep
this part.

It appears to be possible to configure the GPU to restrict access to
addresses within the VRAM pool, but this is not done yet.  So for now
the GPU will refuse to load if there is no sort of mmu.  Once address
based limits are supported and tested to confirm that we aren't giving
the GPU access to arbitrary memory, this restriction can be lifted

Signed-off-by: Rob Clark <robdclark@gmail.com>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/gpu/drm/msm/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/mdp4/mdp4_kms.c
index 8972ac35a43d..bab8cbc6d798 100644
--- a/drivers/gpu/drm/msm/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/mdp4/mdp4_kms.c
@@ -17,6 +17,7 @@
 
 
 #include "msm_drv.h"
+#include "msm_mmu.h"
 #include "mdp4_kms.h"
 
 static struct mdp4_platform_config *mdp4_get_config(struct platform_device *dev);
@@ -260,6 +261,7 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev)
 	struct mdp4_platform_config *config = mdp4_get_config(pdev);
 	struct mdp4_kms *mdp4_kms;
 	struct msm_kms *kms = NULL;
+	struct msm_mmu *mmu;
 	int ret;
 
 	mdp4_kms = kzalloc(sizeof(*mdp4_kms), GFP_KERNEL);
@@ -322,12 +324,6 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev)
 	clk_set_rate(mdp4_kms->clk, config->max_clk);
 	clk_set_rate(mdp4_kms->lut_clk, config->max_clk);
 
-	if (!config->iommu) {
-		dev_err(dev->dev, "no iommu\n");
-		ret = -ENXIO;
-		goto fail;
-	}
-
 	/* make sure things are off before attaching iommu (bootloader could
 	 * have left things on, in which case we'll start getting faults if
 	 * we don't disable):
@@ -337,12 +333,23 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev)
 	mdp4_write(mdp4_kms, REG_MDP4_DSI_ENABLE, 0);
 	mdelay(16);
 
-	ret = msm_iommu_attach(dev, config->iommu,
-			iommu_ports, ARRAY_SIZE(iommu_ports));
-	if (ret)
-		goto fail;
+	if (config->iommu) {
+		mmu = msm_iommu_new(dev, config->iommu);
+		if (IS_ERR(mmu)) {
+			ret = PTR_ERR(mmu);
+			goto fail;
+		}
+		ret = mmu->funcs->attach(mmu, iommu_ports,
+				ARRAY_SIZE(iommu_ports));
+		if (ret)
+			goto fail;
+	} else {
+		dev_info(dev->dev, "no iommu, fallback to phys "
+				"contig buffers for scanout\n");
+		mmu = NULL;
+	}
 
-	mdp4_kms->id = msm_register_iommu(dev, config->iommu);
+	mdp4_kms->id = msm_register_mmu(dev, mmu);
 	if (mdp4_kms->id < 0) {
 		ret = mdp4_kms->id;
 		dev_err(dev->dev, "failed to register mdp4 iommu: %d\n", ret);