staging: drm/omap: mmap of tiled buffers with stride >4kb

Deal with the case of buffers with virtual stride larger than one
page in fault_2d().

Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 59 insertions, 27 deletions

diff --git a/drivers/staging/omapdrm/omap_gem.c b/drivers/staging/omapdrm/omap_gem.c
index 5abd294ab2e..921f058cc6a 100644
--- a/drivers/staging/omapdrm/omap_gem.c
+++ b/drivers/staging/omapdrm/omap_gem.c
@@ -153,10 +153,23 @@ static void evict_entry(struct drm_gem_object *obj,
                 enum tiler_fmt fmt, struct usergart_entry *entry)
 {
         if (obj->dev->dev_mapping) {
-                size_t size = PAGE_SIZE * usergart[fmt].height;
+                struct omap_gem_object *omap_obj = to_omap_bo(obj);
+                int n = usergart[fmt].height;
+                size_t size = PAGE_SIZE * n;
                 loff_t off = mmap_offset(obj) +
                                 (entry->obj_pgoff << PAGE_SHIFT);
-                unmap_mapping_range(obj->dev->dev_mapping, off, size, 1);
+                const int m = 1 + ((omap_obj->width << fmt) / PAGE_SIZE);
+                if (m > 1) {
+                        int i;
+                        /* if stride > than PAGE_SIZE then sparse mapping: */
+                        for (i = n; i > 0; i--) {
+                                unmap_mapping_range(obj->dev->dev_mapping,
+                                                off, PAGE_SIZE, 1);
+                                off += PAGE_SIZE * m;
+                        }
+                } else {
+                        unmap_mapping_range(obj->dev->dev_mapping, off, size, 1);
+                }
         }
 
         entry->obj = NULL;
@@ -342,26 +355,39 @@ static int fault_2d(struct drm_gem_object *obj,
         void __user *vaddr;
         int i, ret, slots;
 
-        if (!usergart)
-                return -EFAULT;
-
-        /* TODO: this fxn might need a bit tweaking to deal w/ tiled buffers
-         * that are wider than 4kb
+        /*
+         * Note the height of the slot is also equal to the number of pages
+         * that need to be mapped in to fill 4kb wide CPU page.  If the slot
+         * height is 64, then 64 pages fill a 4kb wide by 64 row region.
+         */
+        const int n = usergart[fmt].height;
+        const int n_shift = usergart[fmt].height_shift;
+
+        /*
+         * If buffer width in bytes > PAGE_SIZE then the virtual stride is
+         * rounded up to next multiple of PAGE_SIZE.. this need to be taken
+         * into account in some of the math, so figure out virtual stride
+         * in pages
          */
+        const int m = 1 + ((omap_obj->width << fmt) / PAGE_SIZE);
 
         /* We don't use vmf->pgoff since that has the fake offset: */
         pgoff = ((unsigned long)vmf->virtual_address -
                         vma->vm_start) >> PAGE_SHIFT;
 
-        /* actual address we start mapping at is rounded down to previous slot
+        /*
+         * Actual address we start mapping at is rounded down to previous slot
          * boundary in the y direction:
          */
-        base_pgoff = round_down(pgoff, usergart[fmt].height);
-        vaddr = vmf->virtual_address - ((pgoff - base_pgoff) << PAGE_SHIFT);
-        entry = &usergart[fmt].entry[usergart[fmt].last];
+        base_pgoff = round_down(pgoff, m << n_shift);
 
+        /* figure out buffer width in slots */
         slots = omap_obj->width >> usergart[fmt].slot_shift;
 
+        vaddr = vmf->virtual_address - ((pgoff - base_pgoff) << PAGE_SHIFT);
+
+        entry = &usergart[fmt].entry[usergart[fmt].last];
+
         /* evict previous buffer using this usergart entry, if any: */
         if (entry->obj)
                 evict_entry(entry->obj, fmt, entry);
@@ -369,23 +395,30 @@ static int fault_2d(struct drm_gem_object *obj,
         entry->obj = obj;
         entry->obj_pgoff = base_pgoff;
 
-        /* now convert base_pgoff to phys offset from virt offset:
-         */
-        base_pgoff = (base_pgoff >> usergart[fmt].height_shift) * slots;
-
-        /* map in pages.  Note the height of the slot is also equal to the
-         * number of pages that need to be mapped in to fill 4kb wide CPU page.
-         * If the height is 64, then 64 pages fill a 4kb wide by 64 row region.
-         * Beyond the valid pixel part of the buffer, we set pages[i] to NULL to
-         * get a dummy page mapped in.. if someone reads/writes it they will get
-         * random/undefined content, but at least it won't be corrupting
-         * whatever other random page used to be mapped in, or other undefined
-         * behavior.
+        /* now convert base_pgoff to phys offset from virt offset: */
+        base_pgoff = (base_pgoff >> n_shift) * slots;
+
+        /* for wider-than 4k.. figure out which part of the slot-row we want: */
+        if (m > 1) {
+                int off = pgoff % m;
+                entry->obj_pgoff += off;
+                base_pgoff /= m;
+                slots = min(slots - (off << n_shift), n);
+                base_pgoff += off << n_shift;
+                vaddr += off << PAGE_SHIFT;
+        }
+
+        /*
+         * Map in pages. Beyond the valid pixel part of the buffer, we set
+         * pages[i] to NULL to get a dummy page mapped in.. if someone
+         * reads/writes it they will get random/undefined content, but at
+         * least it won't be corrupting whatever other random page used to
+         * be mapped in, or other undefined behavior.
          */
         memcpy(pages, &omap_obj->pages[base_pgoff],
                         sizeof(struct page *) * slots);
         memset(pages + slots, 0,
-                        sizeof(struct page *) * (usergart[fmt].height - slots));
+                        sizeof(struct page *) * (n - slots));
 
         ret = tiler_pin(entry->block, pages, ARRAY_SIZE(pages), 0, true);
         if (ret) {
@@ -393,16 +426,15 @@ static int fault_2d(struct drm_gem_object *obj,
                 return ret;
         }
 
-        i = usergart[fmt].height;
         pfn = entry->paddr >> PAGE_SHIFT;
 
         VERB("Inserting %p pfn %lx, pa %lx", vmf->virtual_address,
                         pfn, pfn << PAGE_SHIFT);
 
-        while (i--) {
+        for (i = n; i > 0; i--) {
                 vm_insert_mixed(vma, (unsigned long)vaddr, pfn);
                 pfn += usergart[fmt].stride_pfn;
-                vaddr += PAGE_SIZE;
+                vaddr += PAGE_SIZE * m;
         }
 
         /* simple round-robin: */