Re: [PATCH v2 1/4] drm/dp_mst: Add some atomic state iterator macros

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Oct 26, 2018 at 04:35:46PM -0400, Lyude Paul wrote:
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> ---
>  include/drm/drm_dp_mst_helper.h | 77 +++++++++++++++++++++++++++++++++
>  1 file changed, 77 insertions(+)
> 
> diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
> index 59f005b419cf..3faceb66f5cb 100644
> --- a/include/drm/drm_dp_mst_helper.h
> +++ b/include/drm/drm_dp_mst_helper.h
> @@ -628,4 +628,81 @@ int drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
>  int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
>  				 struct drm_dp_mst_port *port, bool power_up);
>  
> +extern const struct drm_private_state_funcs drm_dp_mst_topology_state_funcs;
> +
> +static inline bool
> +__drm_dp_mst_state_iter_get(struct drm_atomic_state *state,
> +			    struct drm_dp_mst_topology_mgr **mgr,
> +			    struct drm_dp_mst_topology_state **old_state,
> +			    struct drm_dp_mst_topology_state **new_state,
> +			    int i)
> +{
> +	struct __drm_private_objs_state *objs_state = &state->private_objs[i];
> +
> +	if (objs_state->ptr->funcs != &drm_dp_mst_topology_state_funcs)
> +		return false;
> +
> +	*mgr = to_dp_mst_topology_mgr(objs_state->ptr);
> +	if (old_state)
> +		*old_state = to_dp_mst_topology_state(objs_state->old_state);
> +	if (new_state)
> +		*new_state = to_dp_mst_topology_state(objs_state->new_state);
> +
> +	return true;
> +}
> +
> +/**
> + * for_each_oldnew_mst_mgr_in_state - iterate over all DP MST topology
> + * managers in an atomic update
> + * @__state: &struct drm_atomic_state pointer
> + * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
> + * @old_state: &struct drm_dp_mst_topology_state iteration cursor for the old
> + * state
> + * @new_state: &struct drm_dp_mst_topology_state iteration cursor for the new
> + * state
> + * @__i: int iteration cursor, for macro-internal use
> + *
> + * This iterates over all DRM DP MST topology managers in an atomic update,
> + * tracking both old and new state. This is useful in places where the state
> + * delta needs to be considered, for example in atomic check functions.
> + */
> +#define for_each_oldnew_mst_mgr_in_state(__state, mgr, old_state, new_state, __i) \
> +	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
> +		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), &(old_state), &(new_state), (__i)))

I just realized that all our iterator macros do not compose at all. Whic
is rather disappointing :-/

list_for_each solves that with a list_for_each_member, which you can then
easily use to create more specialized macros. I wonder whether we should
have a master macros, which also takes the obj type (we have very uniform
naming, so a few well placed ## should make this work neatly), and then
you could just #define more specialized iterators without having to retype
them (or the need for dummy iterator markers and tons of casting).

Anyway, that's a lament for another day&patch. This looks good.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> +
> +/**
> + * for_each_old_mst_mgr_in_state - iterate over all DP MST topology managers
> + * in an atomic update
> + * @__state: &struct drm_atomic_state pointer
> + * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
> + * @old_state: &struct drm_dp_mst_topology_state iteration cursor for the old
> + * state
> + * @__i: int iteration cursor, for macro-internal use
> + *
> + * This iterates over all DRM DP MST topology managers in an atomic update,
> + * tracking only the old state. This is useful in disable functions, where we
> + * need the old state the hardware is still in.
> + */
> +#define for_each_old_mst_mgr_in_state(__state, mgr, old_state, __i) \
> +	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
> +		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), &(old_state), NULL, (__i)))
> +
> +/**
> + * for_each_new_mst_mgr_in_state - iterate over all DP MST topology managers
> + * in an atomic update
> + * @__state: &struct drm_atomic_state pointer
> + * @mgr: &struct drm_dp_mst_topology_mgr iteration cursor
> + * @new_state: &struct drm_dp_mst_topology_state iteration cursor for the new
> + * state
> + * @__i: int iteration cursor, for macro-internal use
> + *
> + * This iterates over all DRM DP MST topology managers in an atomic update,
> + * tracking only the new state. This is useful in enable functions, where we
> + * need the new state the hardware should be in when the atomic commit
> + * operation has completed.
> + */
> +#define for_each_new_mst_mgr_in_state(__state, mgr, new_state, __i) \
> +	for ((__i) = 0; (__i) < (__state)->num_private_objs; (__i)++) \
> +		for_each_if(__drm_dp_mst_state_iter_get((__state), &(mgr), NULL, &(new_state), (__i)))
> +
>  #endif
> -- 
> 2.17.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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