/*
* Copyright (C) 2013 Red Hat
* Author: Rob Clark <robdclark@gmail.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "mdp5_kms.h"
#include "mdp5_smp.h"
/* SMP - Shared Memory Pool
*
* These 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.
*
* For each block, it can be either free, or pending/in-use by a
* client. The updates happen in three steps:
*
* 1) mdp5_smp_request():
* When plane scanout is setup, calculate required number of
* blocks needed per client, and request. Blocks not inuse or
* pending by any other client are added to client's pending
* set.
*
* 2) mdp5_smp_configure():
* As hw is programmed, before FLUSH, MDP5_SMP_ALLOC registers
* are configured for the union(pending, inuse)
*
* 3) mdp5_smp_commit():
* After next vblank, copy pending -> inuse. Optionally update
* MDP5_SMP_ALLOC registers if there are newly unused blocks
*
* On the next vblank after changes have been committed to hw, the
* client's pending blocks become it's in-use blocks (and no-longer
* in-use blocks become available to other clients).
*
* btw, hurray for confusing overloaded acronyms! :-/
*
* NOTE: for atomic modeset/pageflip NONBLOCK operations, step #1
* should happen at (or before)? atomic->check(). And we'd need
* an API to discard previous requests if update is aborted or
* (test-only).
*
* TODO would perhaps be nice to have debugfs to dump out kernel
* inuse and pending state of all clients..
*/
static DEFINE_SPINLOCK(smp_lock);
/* step #1: update # of blocks pending for the client: */
int mdp5_smp_request(struct mdp5_kms *mdp5_kms,
enum mdp5_client_id cid, int nblks)
{
struct mdp5_client_smp_state *ps = &mdp5_kms->smp_client_state[cid];
int i, ret, avail, cur_nblks, cnt = mdp5_kms->smp_blk_cnt;
unsigned long flags;
spin_lock_irqsave(&smp_lock, flags);
avail = cnt - bitmap_weight(mdp5_kms->smp_state, cnt);
if (nblks > avail) {
ret = -ENOSPC;
goto fail;
}
cur_nblks = bitmap_weight(ps->pending, cnt);
if (nblks > cur_nblks) {
/* grow the existing pending reservation: */
for (i = cur_nblks; i < nblks; i++) {
int blk = find_first_zero_bit(mdp5_kms->smp_state, cnt);
set_bit(blk, ps->pending);
set_bit(blk, mdp5_kms->smp_state);
}
} else {
/* shrink the existing pending reservation: */
for (i = cur_nblks; i > nblks; i--) {
int blk = find_first_bit(ps->pending, cnt);
clear_bit(blk, ps->pending);
/* don't clear in global smp_state until _commit() */
}
}
fail:
spin_unlock_irqrestore(&smp_lock, flags);
return 0;
}
static void update_smp_state(struct mdp5_kms *mdp5_kms,
enum mdp5_client_id cid, mdp5_smp_state_t *assigned)
{
int cnt = mdp5_kms->smp_blk_cnt;
uint32_t blk, val;
for_each_set_bit(blk, *assigned, cnt) {
int idx = blk / 3;
int fld = blk % 3;
val = mdp5_read(mdp5_kms, REG_MDP5_SMP_ALLOC_W_REG(idx));
switch (fld) {
case 0:
val &= ~MDP5_SMP_ALLOC_W_REG_CLIENT0__MASK;
val |= MDP5_SMP_ALLOC_W_REG_CLIENT0(cid);
break;
case 1:
val &= ~MDP5_SMP_ALLOC_W_REG_CLIENT1__MASK;
val |= MDP5_SMP_ALLOC_W_REG_CLIENT1(cid);
break;
case 2:
val &= ~MDP5_SMP_ALLOC_W_REG_CLIENT2__MASK;
val |= MDP5_SMP_ALLOC_W_REG_CLIENT2(cid);
break;
}
mdp5_write(mdp5_kms, REG_MDP5_SMP_ALLOC_W_REG(idx), val);
mdp5_write(mdp5_kms, REG_MDP5_SMP_ALLOC_R_REG(idx), val);
}
}
/* step #2: configure hw for union(pending, inuse): */
void mdp5_smp_configure(struct mdp5_kms *mdp5_kms, enum mdp5_client_id cid)
{
struct mdp5_client_smp_state *ps = &mdp5_kms->smp_client_state[cid];
int cnt = mdp5_kms->smp_blk_cnt;
mdp5_smp_state_t assigned;
bitmap_or(assigned, ps->inuse, ps->pending, cnt);
update_smp_state(mdp5_kms, cid, &assigned);
}
/* step #3: after vblank, copy pending -> inuse: */
void mdp5_smp_commit(struct mdp5_kms *mdp5_kms, enum mdp5_client_id cid)
{
struct mdp5_client_smp_state *ps = &mdp5_kms->smp_client_state[cid];
int cnt = mdp5_kms->smp_blk_cnt;
mdp5_smp_state_t released;
/*
* Figure out if there are any blocks we where previously
* using, which can be released and made available to other
* clients:
*/
if (bitmap_andnot(released, ps->inuse, ps->pending, cnt)) {
unsigned long flags;
spin_lock_irqsave(&smp_lock, flags);
/* clear released blocks: */
bitmap_andnot(mdp5_kms->smp_state, mdp5_kms->smp_state,
released, cnt);
spin_unlock_irqrestore(&smp_lock, flags);
update_smp_state(mdp5_kms, CID_UNUSED, &released);
}
bitmap_copy(ps->inuse, ps->pending, cnt);
}
