[Intel-gfx] [RFC 32/60] drm/i915/lmem: support pread
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Fri Jul 10 12:39:32 UTC 2020
On 10/07/2020 12:57, Matthew Auld wrote:
> We need to add support for pread'ing an LMEM object.
>
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Signed-off-by: Steve Hampson <steven.t.hampson at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_lmem.c | 112 ++++++++++++++++++
> drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 6 +
> .../gpu/drm/i915/gem/i915_gem_object_types.h | 2 +
> drivers/gpu/drm/i915/i915_gem.c | 6 +
> 4 files changed, 126 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> index 932ee21e6609..9142ba299aa1 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> @@ -8,6 +8,92 @@
> #include "gem/i915_gem_lmem.h"
> #include "i915_drv.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_wait(obj,
> + I915_WAIT_INTERRUPTIBLE,
> + MAX_SCHEDULE_TIMEOUT);
> + if (ret)
> + return 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_atomic(obj, idx);
> + if (!vaddr) {
> + ret = -ENOMEM;
> + goto out_put;
> + }
> + unwritten = __copy_to_user_inatomic(user_data,
> + (void __force *)vaddr + offset,
> + length);
> + io_mapping_unmap_atomic(vaddr);
> + if (unwritten) {
> + vaddr = i915_gem_object_lmem_io_map_page(obj, idx);
> + unwritten = copy_to_user(user_data,
> + (void __force *)vaddr + offset,
> + length);
> + io_mapping_unmap(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;
> +}
> +
> const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
> .name = "i915_gem_object_lmem",
> .flags = I915_GEM_OBJECT_HAS_IOMEM,
> @@ -15,8 +101,34 @@ const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
> .get_pages = i915_gem_object_get_pages_buddy,
> .put_pages = i915_gem_object_put_pages_buddy,
> .release = i915_gem_object_release_memory_region,
> +
> + .pread = lmem_pread,
> };
>
> +void __iomem *
> +i915_gem_object_lmem_io_map_page(struct drm_i915_gem_object *obj,
> + unsigned long n)
> +{
> + resource_size_t offset;
> +
> + offset = i915_gem_object_get_dma_address(obj, n);
> + offset -= obj->mm.region->region.start;
> +
> + return io_mapping_map_wc(&obj->mm.region->iomap, offset, PAGE_SIZE);
> +}
> +
> +void __iomem *
> +i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
> + unsigned long n)
> +{
> + resource_size_t offset;
> +
> + offset = i915_gem_object_get_dma_address(obj, n);
> + offset -= obj->mm.region->region.start;
> +
> + return io_mapping_map_atomic_wc(&obj->mm.region->iomap, offset);
> +}
> +
> bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj)
> {
> return obj->ops == &i915_gem_lmem_obj_ops;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> index fc3f15580fe3..a24d94bc380f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> @@ -14,6 +14,12 @@ struct intel_memory_region;
>
> extern const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops;
>
> +void __iomem *i915_gem_object_lmem_io_map_page(struct drm_i915_gem_object *obj,
> + unsigned long n);
> +void __iomem *
> +i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
> + unsigned long n);
> +
> bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj);
>
> struct drm_i915_gem_object *
> 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 5335f799b548..b37ae7b32f53 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> @@ -56,6 +56,8 @@ 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 9aa3066cb75d..1805b5e6bc30 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -519,6 +519,12 @@ 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);
>
It would be really nice to consolidate the redundant
wait/lock/pin/domain management between smem and lmem paths (new vfunc
vs the existing code). Maybe pull out all the common operations and to
the rest wholly via vfuncs?
Or maybe bits of Maarten's "drm/i915: Remove locking from
i915_gem_object_prepare_read/write" could be used here, not sure without
a deeper look. Just wanting to pencil this area for rework hopefully
before the merge.
Regards,
Tvrtko
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