4  * SPDX-License-Identifier: MIT
14  * fetching up to 3 subsequent CP_INDIRECT_BUFFER contents into the ROQ before
23  *       CP_FOO <- PFP/SQE is reading from here
25  *       CP_BAR <- ROQ has prefetched up to here
33  *      CP_FOO <- PFP/SQE is reading here
37  *      CP_BAR <- ROQ has prefetched up to here
40  * larger than the size of the second IB, indicating that we need to back up
48  *       CP_FOO <- PFP/SQE IB2 is reading here
53  *       CP_BAR <- ROQ IB2 has prefetched up to here
55  * CP_BAZ <- PFP/SQE IB1 is reading here
63  * cmdstream at the time of the crash, we do a pre-pass scanning the
66  * we find the IB1 position that is being read into ROQ, we backtrack until
67  * we find the IB1 position that SQE is at, and (roughly) repeat the process
85    s->history[s->next++ % ARRAY_SIZE(s->history)] = *ib;  in push_ib()
86    s->num = MIN2(s->num + 1, ARRAY_SIZE(s->history));  in push_ib()
92    if ((n >= s->num) || (n < 0))  in get_ib()
94    int idx = s->next - (s->num - n);  in get_ib()
95    return &s->history[idx % ARRAY_SIZE(s->history)];  in get_ib()
101    s->num = s->next = 0;  in reset_state()
105  * Once we find the ROQ prefetch position, work backwards to find the SQE
113    for (int n = s->num - 1; n >= 0; n--) {  in reverse_prefetch()
115       if (ib->ibsize > rem) {  in reverse_prefetch()
117          options.ibs[lvl].base = ib->ibaddr;  in reverse_prefetch()
122       rem -= ib->ibsize;  in reverse_prefetch()
130  * of consecutive CP_INDIRECT_BUFFER packets, until we find the one that
146             parse_cp_indirect(&dwords[1], count - 1, &ibaddr, &ibsize);  in scan_cmdstream()
150              * search backwards from here to find the SQE position:  in scan_cmdstream()
169       dwords_left -= count;  in scan_cmdstream()
190    /* Once we find the actual IB1 position, we need to find the IB2 position.  in handle_prefetch()
193     * have a history of enough  RB->IB1 IB's, so we can simply scan forward  in handle_prefetch()
194     * from our oldest history entry until we find the IB2 match..  in handle_prefetch()
198       uint32_t *ibaddr = hostptr(ib->ibaddr);  in handle_prefetch()
201       struct ib *ib2 = scan_cmdstream(&ib1_state, 2, ibaddr, ib->ibsize);  in handle_prefetch()
209        *    IB1:CP_INDIRECT_BUFFER  <-- detected IB1 position  in handle_prefetch()
213        * reset the IB1 crash position back to the oldest RB->IB1 IB that we  in handle_prefetch()
226        * in IB1 to setup for the next tile, breaking up prefetch.  in handle_prefetch()
232          options.ibs[1].base = first_rb_ib->ibaddr;  in handle_prefetch()
233          options.ibs[1].rem = first_rb_ib->ibsize;  in handle_prefetch()