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drm/dp: Add DP MST helpers to atomically find and release vcpi slots 

drm_dp_atomic_find_vcpi_slots() should be called from ->atomic_check() to
check there are sufficient vcpi slots for a mode and to add that to the
state. This should be followed by a call to drm_dp_mst_allocate_vcpi()
in ->atomic_commit() to initialize a struct vcpi for the port.

drm_dp_atomic_release_vcpi_slots() should be called from
->atomic_check() to release a port's vcpi slot allocation from the
state.

Drivers that do not make use of this atomic helper are expected to call
drm_dp_find_vcpi_slots() instead before calling
drm_dp_mst_allocate_vcpi().

v3: drm_dp_atomic_release_vcpi_slots() now needs to know how many slots
    to release as we may not have a valid reference to port.
v2:
Added checks for verifying the port reference is valid
Moved get_mst_topology_state() into the helpers (Daniel)
Changed find_vcpi_slots() to not depend on current allocation

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Harry Wentland <Harry.wentland@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1492753893-3748-4-git-send-email-dhinakaran.pandiyan@intel.com
This commit is contained in:
Pandiyan, Dhinakaran 2017-04-20 22:51:32 -07:00 committed by Maarten Lankhorst
parent 3f3353b7e1
commit edb1ed1ab7
2 changed files with 81 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

75
drivers/gpu/drm/drm_dp_mst_topology.c
View File

@ -2497,6 +2497,81 @@ static int drm_dp_init_vcpi(struct drm_dp_mst_topology_mgr *mgr,
return 0;
}
/**
* drm_dp_atomic_find_vcpi_slots() - Find and add vcpi slots to the state
* @state: global atomic state
* @mgr: MST topology manager for the port
* @port: port to find vcpi slots for
* @pbn: bandwidth required for the mode in PBN
*
* RETURNS:
* Total slots in the atomic state assigned for this port or error
*/
int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port, int pbn)
{
struct drm_dp_mst_topology_state *topology_state;
int req_slots;
topology_state = drm_atomic_get_mst_topology_state(state, mgr);
if (topology_state == NULL)
return -ENOMEM;
port = drm_dp_get_validated_port_ref(mgr, port);
if (port == NULL)
return -EINVAL;
req_slots = DIV_ROUND_UP(pbn, mgr->pbn_div);
DRM_DEBUG_KMS("vcpi slots req=%d, avail=%d\n",
req_slots, topology_state->avail_slots);
if (req_slots > topology_state->avail_slots) {
drm_dp_put_port(port);
return -ENOSPC;
}
topology_state->avail_slots -= req_slots;
DRM_DEBUG_KMS("vcpi slots avail=%d", topology_state->avail_slots);
drm_dp_put_port(port);
return req_slots;
}
EXPORT_SYMBOL(drm_dp_atomic_find_vcpi_slots);
/**
* drm_dp_atomic_release_vcpi_slots() - Release allocated vcpi slots
* @state: global atomic state
* @mgr: MST topology manager for the port
* @slots: number of vcpi slots to release
*
* RETURNS:
* 0 if @slots were added back to &drm_dp_mst_topology_state->avail_slots or
* negative error code
*/
int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr,
int slots)
{
struct drm_dp_mst_topology_state *topology_state;
topology_state = drm_atomic_get_mst_topology_state(state, mgr);
if (topology_state == NULL)
return -ENOMEM;
/* We cannot rely on port->vcpi.num_slots to update
* topology_state->avail_slots as the port may not exist if the parent
* branch device was unplugged. This should be fixed by tracking
* per-port slot allocation in drm_dp_mst_topology_state instead of
* depending on the caller to tell us how many slots to release.
*/
topology_state->avail_slots += slots;
DRM_DEBUG_KMS("vcpi slots released=%d, avail=%d\n",
slots, topology_state->avail_slots);
return 0;
}
EXPORT_SYMBOL(drm_dp_atomic_release_vcpi_slots);
/**
* drm_dp_mst_allocate_vcpi() - Allocate a virtual channel
* @mgr: manager for this port

6
include/drm/drm_dp_mst_helper.h
View File

@ -615,5 +615,11 @@ void drm_dp_mst_topology_mgr_suspend(struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_mst_topology_mgr_resume(struct drm_dp_mst_topology_mgr *mgr);
struct drm_dp_mst_topology_state *drm_atomic_get_mst_topology_state(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr);
int drm_dp_atomic_find_vcpi_slots(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port, int pbn);
int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
struct drm_dp_mst_topology_mgr *mgr,
int slots);
#endif