drm/msm/mdp5: handle SMP block allocations "atomically"

Previously, SMP block allocation was not checked in the plane's
atomic_check() fxn, so we could fail allocation SMP block allocation at
atomic_update() time.  Re-work the block allocation to request blocks
during atomic_check(), but not update the hw until committing the atomic
update.

Since SMP blocks allocated at atomic_check() time, we need to manage the
SMP state as part of mdp5_state (global atomic state).  This actually
ends up significantly simplifying the SMP management, as the SMP module
does not need to manage the intermediate state between assigning new
blocks before setting flush bits and releasing old blocks after vblank.
(The SMP registers and SMP allocation is not double-buffered, so newly
allocated blocks need to be updated in kms->prepare_commit() released
blocks in kms->complete_commit().)

Signed-off-by: Rob Clark <robdclark@gmail.com>

1 files changed, 56 insertions, 10 deletions

diff --git a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.h b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.h
index 20b87e800ea3..10bdd9fc0e88 100644
--- a/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.h
+++ b/drivers/gpu/drm/msm/mdp/mdp5/mdp5_smp.h
@@ -21,10 +21,49 @@
 
 #include "msm_drv.h"
 
-struct mdp5_client_smp_state {
-	mdp5_smp_state_t inuse;
-	mdp5_smp_state_t configured;
-	mdp5_smp_state_t pending;
+/*
+ * SMP - Shared Memory Pool:
+ *
+ * SMP blocks are shared between all the clients, where each plane in
+ * a scanout buffer is a SMP client.  Ie. scanout of 3 plane I420 on
+ * pipe VIG0 => 3 clients: VIG0_Y, VIG0_CB, VIG0_CR.
+ *
+ * Based on the size of the attached scanout buffer, a certain # of
+ * blocks must be allocated to that client out of the shared pool.
+ *
+ * In some hw, some blocks are statically allocated for certain pipes
+ * and CANNOT be re-allocated (eg: MMB0 and MMB1 both tied to RGB0).
+ *
+ *
+ * Atomic SMP State:
+ *
+ * On atomic updates that modify SMP configuration, the state is cloned
+ * (copied) and modified.  For test-only, or in cases where atomic
+ * update fails (or if we hit ww_mutex deadlock/backoff condition) the
+ * new state is simply thrown away.
+ *
+ * Because the SMP registers are not double buffered, updates are a
+ * two step process:
+ *
+ * 1) in _prepare_commit() we configure things (via read-modify-write)
+ *    for the newly assigned pipes, so we don't take away blocks
+ *    assigned to pipes that are still scanning out
+ * 2) in _complete_commit(), after vblank/etc, we clear things for the
+ *    released clients, since at that point old pipes are no longer
+ *    scanning out.
+ */
+struct mdp5_smp_state {
+	/* global state of what blocks are in use: */
+	mdp5_smp_state_t state;
+
+	/* per client state of what blocks they are using: */
+	mdp5_smp_state_t client_state[MAX_CLIENTS];
+
+	/* assigned pipes (hw updated at _prepare_commit()): */
+	unsigned long assigned;
+
+	/* released pipes (hw updated at _complete_commit()): */
+	unsigned long released;
 };
 
 struct mdp5_kms;
@@ -36,13 +75,20 @@ struct mdp5_smp;
  * which is then used to call the other mdp5_smp_*(handler, ...) functions.
  */
 
-struct mdp5_smp *mdp5_smp_init(struct drm_device *dev, const struct mdp5_smp_block *cfg);
+struct mdp5_smp *mdp5_smp_init(struct mdp5_kms *mdp5_kms,
+		const struct mdp5_smp_block *cfg);
 void  mdp5_smp_destroy(struct mdp5_smp *smp);
 
-int  mdp5_smp_request(struct mdp5_smp *smp, enum mdp5_pipe pipe,
-		const struct mdp_format *format, u32 width, bool hdecim);
-void mdp5_smp_configure(struct mdp5_smp *smp, enum mdp5_pipe pipe);
-void mdp5_smp_commit(struct mdp5_smp *smp, enum mdp5_pipe pipe);
-void mdp5_smp_release(struct mdp5_smp *smp, enum mdp5_pipe pipe);
+uint32_t mdp5_smp_calculate(struct mdp5_smp *smp,
+		const struct mdp_format *format,
+		u32 width, bool hdecim);
+
+int mdp5_smp_assign(struct mdp5_smp *smp, struct mdp5_smp_state *state,
+		enum mdp5_pipe pipe, uint32_t blkcfg);
+void mdp5_smp_release(struct mdp5_smp *smp, struct mdp5_smp_state *state,
+		enum mdp5_pipe pipe);
+
+void mdp5_smp_prepare_commit(struct mdp5_smp *smp, struct mdp5_smp_state *state);
+void mdp5_smp_complete_commit(struct mdp5_smp *smp, struct mdp5_smp_state *state);
 
 #endif /* __MDP5_SMP_H__ */