On 2019-11-16 5:01 p.m., mikita.lipski@xxxxxxx wrote:
> From: Mikita Lipski <mikita.lipski@xxxxxxx>
>
> Adding a helper function to be called by
> drivers outside of DRM to enable DSC on
> the MST ports.
>
> Function is called to recalculate VCPI allocation
> if DSC is enabled and raise the DSC flag to enable.
> In case of disabling DSC the flag is set to false
> and recalculation of VCPI slots is expected to be done
> in encoder's atomic_check.
>
> v2: squash separate functions into one and call it per
> port
>
> Cc: Harry Wentland <harry.wentland@xxxxxxx>
> Cc: Lyude Paul <lyude@xxxxxxxxxx>
> Signed-off-by: Mikita Lipski <mikita.lipski@xxxxxxx>
> ---
> drivers/gpu/drm/drm_dp_mst_topology.c | 61 +++++++++++++++++++++++++++
> include/drm/drm_dp_mst_helper.h | 5 +++
> 2 files changed, 66 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 94bb259ab73e..98cc93d5ddd7 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3876,6 +3876,67 @@ drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
> return 0;
> }
>
> +/**
> + * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
> + * @state: Pointer to the new drm_atomic_state
> + * @pointer: Pointer to the affected MST Port
s/@pointer/@port/
> + * @pbn: Newly recalculated bw required for link with DSC enabled
> + * @pbn_div: Divider to calculate correct number of pbn per slot
> + * @enable: Boolean flag enabling or disabling DSC on the port
> + *
> + * This function enables DSC on the given Port
> + * by recalculating its vcpi from pbn provided
> + * and sets dsc_enable flag to keep track of which
> + * ports have DSC enabled
Would be good to document the return value as well.
> + *
> + */
> +int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> + struct drm_dp_mst_port *port,
> + int pbn, int pbn_div,
> + bool enable)
> +{
> + struct drm_dp_mst_topology_state *mst_state;
> + struct drm_dp_vcpi_allocation *pos;
> + bool found = false;
> + int vcpi = 0;
> +
> + mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
> +
> + if (IS_ERR(mst_state))
> + return PTR_ERR(mst_state);
> +
> + list_for_each_entry(pos, &mst_state->vcpis, next) {
> + if (pos->port == port) {
> + found = true;
> + break;
> + }
> + }
> +
> + if (!found) {
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
> + port, mst_state);
> + return -EINVAL;
> + }
> +
> + if (pos->dsc_enabled == enable) {
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
> + port, enable, pos->vcpi);
> + vcpi = pos->vcpi;
Do we want to early return here?
- Leo
> + }
> +
> + if (enable) {
> + vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
> + DRM_DEBUG_ATOMIC("[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
> + port, vcpi);
> + if (vcpi < 0)
> + return -EINVAL;
> + }
> +
> + pos->dsc_enabled = enable;
> +
> + return vcpi;
> +}
> +EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
> /**
> * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
> * atomic update is valid
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index fc19094b06c3..b1b00de3083b 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -431,6 +431,7 @@ struct drm_dp_payload {
> struct drm_dp_vcpi_allocation {
> struct drm_dp_mst_port *port;
> int vcpi;
> + bool dsc_enabled;
> struct list_head next;
> };
>
> @@ -663,6 +664,10 @@ 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 pbn_div);
> +int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
> + struct drm_dp_mst_port *port,
> + int pbn, int pbn_div,
> + bool enable);
> int __must_check
> drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
> struct drm_dp_mst_topology_mgr *mgr,
>
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