[PATCH v2 16/37] drm/i915/lmem: support pread

Matthew Auld
2019-06-27T20:56:54Z

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>
---
.../gpu/drm/i915/gem/i915_gem_object_types.h | 2 +
drivers/gpu/drm/i915/i915_gem.c | 6 ++
drivers/gpu/drm/i915/intel_region_lmem.c | 76 +++++++++++++++++++
3 files changed, 84 insertions(+)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index 80ff5ad9bc07..8cdee185251a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -52,6 +52,8 @@ struct drm_i915_gem_object_ops {
void (*truncate)(struct drm_i915_gem_object *obj);
void (*writeback)(struct drm_i915_gem_object *obj);

+ int (*pread)(struct drm_i915_gem_object *,
+ const struct drm_i915_gem_pread *arg);
int (*pwrite)(struct drm_i915_gem_object *obj,
const struct drm_i915_gem_pwrite *arg);

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 85677ae89849..4ba386ab35e7 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -463,6 +463,12 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,

trace_i915_gem_object_pread(obj, args->offset, args->size);

+ ret = -ENODEV;
+ if (obj->ops->pread)
+ ret = obj->ops->pread(obj, args);
+ if (ret != -ENODEV)
+ goto out;
+
ret = i915_gem_object_wait(obj,
I915_WAIT_INTERRUPTIBLE,
MAX_SCHEDULE_TIMEOUT);
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c
index 701bcac3479e..54b2c7bf177d 100644
--- a/drivers/gpu/drm/i915/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/intel_region_lmem.c
@@ -7,10 +7,86 @@
#include "intel_memory_region.h"
#include "intel_region_lmem.h"

+static int lmem_pread(struct drm_i915_gem_object *obj,
+ const struct drm_i915_gem_pread *arg)
+{
+ struct drm_i915_private *i915 = to_i915(obj->base.dev);
+ struct intel_runtime_pm *rpm = &i915->runtime_pm;
+ intel_wakeref_t wakeref;
+ struct dma_fence *fence;
+ char __user *user_data;
+ unsigned int offset;
+ unsigned long idx;
+ u64 remain;
+ int ret;
+
+ ret = i915_gem_object_pin_pages(obj);
+ if (ret)
+ return ret;
+
+ i915_gem_object_lock(obj);
+ ret = i915_gem_object_set_to_wc_domain(obj, false);
+ if (ret) {
+ i915_gem_object_unlock(obj);
+ goto out_unpin;
+ }
+
+ fence = i915_gem_object_lock_fence(obj);
+ i915_gem_object_unlock(obj);
+ if (!fence) {
+ ret = -ENOMEM;
+ goto out_unpin;
+ }
+
+ wakeref = intel_runtime_pm_get(rpm);
+
+ remain = arg->size;
+ user_data = u64_to_user_ptr(arg->data_ptr);
+ offset = offset_in_page(arg->offset);
+ for (idx = arg->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(rpm, wakeref);
+ i915_gem_object_unlock_fence(obj, fence);
+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 = lmem_pread,
};

static struct drm_i915_gem_object *
--
2.20.1