[RFC PATCH 20/42] drm/i915/lmem: support pread

Matthew Auld
2019-02-14T14:58:08Z

We need to add support for pread'ing an LMEM object.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
---
drivers/gpu/drm/i915/intel_region_lmem.c | 73 ++++++++++++++++++++++++
1 file changed, 73 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c
index c8bee0c18c88..67dc50be2e6b 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/intel_region_lmem.c
@@ -26,10 +26,83 @@
#include "intel_memory_region.h"
#include "intel_region_lmem.h"

+static int region_lmem_pread(struct drm_i915_gem_object *obj,
+ const struct drm_i915_gem_pread *args)
+{
+ struct drm_i915_private *i915 = to_i915(obj->base.dev);
+ intel_wakeref_t wakeref;
+ char __user *user_data;
+ unsigned int offset;
+ unsigned long idx;
+ u64 remain;
+ int ret;
+
+ ret = i915_gem_object_wait(obj,
+ I915_WAIT_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
+ if (ret)
+ return ret;
+
+ ret = i915_gem_object_pin_pages(obj);
+ if (ret)
+ return ret;
+
+ ret = mutex_lock_interruptible(&i915->drm.struct_mutex);
+ if (ret)
+ goto out_unpin;
+
+ wakeref = intel_runtime_pm_get(i915);
+
+ ret = i915_gem_object_set_to_wc_domain(obj, false);
+ mutex_unlock(&i915->drm.struct_mutex);
+ if (ret)
+ goto out_put;
+
+ remain = args->size;
+ user_data = u64_to_user_ptr(args->data_ptr);
+ offset = offset_in_page(args->offset);
+ for (idx = args->offset >> PAGE_SHIFT; remain; idx++) {
+ unsigned long unwritten;
+ void __iomem *vaddr;
+ int length;
+
+ length = remain;
+ if (offset + length > PAGE_SIZE)
+ length = PAGE_SIZE - offset;
+
+ vaddr = i915_gem_object_lmem_io_map_page(obj, idx);
+ if (!vaddr) {
+ ret = -ENOMEM;
+ goto out_put;
+ }
+
+ unwritten = copy_to_user(user_data,
+ (void __force *)vaddr + offset,
+ length);
+ io_mapping_unmap_atomic(vaddr);
+ if (unwritten) {
+ ret = -EFAULT;
+ goto out_put;
+ }
+
+ remain -= length;
+ user_data += length;
+ offset = 0;
+ }
+
+out_put:
+ intel_runtime_pm_put(i915, wakeref);
+out_unpin:
+ i915_gem_object_unpin_pages(obj);
+
+ return ret;
+}
+
static const struct drm_i915_gem_object_ops region_lmem_obj_ops = {
.get_pages = i915_memory_region_get_pages_buddy,
.put_pages = i915_memory_region_put_pages_buddy,
.release = i915_gem_object_release_memory_region,
+ .pread = region_lmem_pread,
};

static struct drm_i915_gem_object *
--
2.20.1