1 // SPDX-License-Identifier: GPL-2.0
3 * Memory arbiter functions. Allocates bandwidth through the
4 * arbiter and sets up arbiter breakpoints.
6 * The algorithm first assigns slots to the clients that has specified
7 * bandwidth (e.g. ethernet) and then the remaining slots are divided
8 * on all the active clients.
10 * Copyright (c) 2004-2007 Axis Communications AB.
12 * The artpec-3 has two arbiters. The memory hierarchy looks like this:
18 * -------------- ------------------
19 * | foo arbiter|----| Internal memory|
20 * -------------- ------------------
39 #include <hwregs/reg_map.h>
40 #include <hwregs/reg_rdwr.h>
41 #include <hwregs/marb_foo_defs.h>
42 #include <hwregs/marb_bar_defs.h>
44 #include <hwregs/intr_vect.h>
45 #include <linux/interrupt.h>
46 #include <linux/irq.h>
47 #include <linux/signal.h>
48 #include <linux/errno.h>
49 #include <linux/spinlock.h>
51 #include <asm/irq_regs.h>
55 struct crisv32_watch_entry
{
56 unsigned long instance
;
63 #define NUMBER_OF_BP 4
64 #define SDRAM_BANDWIDTH 400000000
65 #define INTMEM_BANDWIDTH 400000000
66 #define NBR_OF_SLOTS 64
67 #define NBR_OF_REGIONS 2
68 #define NBR_OF_CLIENTS 15
70 #define UNASSIGNED 100
73 unsigned long instance
;
76 int requested_slots
[NBR_OF_REGIONS
][NBR_OF_CLIENTS
];
77 int active_clients
[NBR_OF_REGIONS
][NBR_OF_CLIENTS
];
80 static struct crisv32_watch_entry watches
[ARBITERS
][NUMBER_OF_BP
] =
96 struct arbiter arbiters
[ARBITERS
] =
98 { /* L2 cache arbiter */
99 .instance
= regi_marb_foo
,
104 .instance
= regi_marb_bar
,
110 static int max_bandwidth
[NBR_OF_REGIONS
] = {SDRAM_BANDWIDTH
, INTMEM_BANDWIDTH
};
112 DEFINE_SPINLOCK(arbiter_lock
);
115 crisv32_foo_arbiter_irq(int irq
, void *dev_id
);
117 crisv32_bar_arbiter_irq(int irq
, void *dev_id
);
120 * "I'm the arbiter, I know the score.
121 * From square one I'll be watching all 64."
122 * (memory arbiter slots, that is)
125 * Program the memory arbiter slots for "region" according to what's
126 * in requested_slots[] and active_clients[], while minimizing
127 * latency. A caller may pass a non-zero positive amount for
128 * "unused_slots", which must then be the unallocated, remaining
129 * number of slots, free to hand out to any client.
132 static void crisv32_arbiter_config(int arbiter
, int region
, int unused_slots
)
139 * This vector corresponds to the hardware arbiter slots (see
140 * the hardware documentation for semantics). We initialize
141 * each slot with a suitable sentinel value outside the valid
142 * range {0 .. NBR_OF_CLIENTS - 1} and replace them with
143 * client indexes. Then it's fed to the hardware.
145 s8 val
[NBR_OF_SLOTS
];
147 for (slot
= 0; slot
< NBR_OF_SLOTS
; slot
++)
150 for (client
= 0; client
< arbiters
[arbiter
].nbr_clients
; client
++) {
152 /* Allocate the requested non-zero number of slots, but
153 * also give clients with zero-requests one slot each
154 * while stocks last. We do the latter here, in client
155 * order. This makes sure zero-request clients are the
156 * first to get to any spare slots, else those slots
157 * could, when bandwidth is allocated close to the limit,
158 * all be allocated to low-index non-zero-request clients
159 * in the default-fill loop below. Another positive but
160 * secondary effect is a somewhat better spread of the
161 * zero-bandwidth clients in the vector, avoiding some of
162 * the latency that could otherwise be caused by the
163 * partitioning of non-zero-bandwidth clients at low
164 * indexes and zero-bandwidth clients at high
165 * indexes. (Note that this spreading can only affect the
166 * unallocated bandwidth.) All the above only matters for
167 * memory-intensive situations, of course.
169 if (!arbiters
[arbiter
].requested_slots
[region
][client
]) {
171 * Skip inactive clients. Also skip zero-slot
172 * allocations in this pass when there are no known
175 if (!arbiters
[arbiter
].active_clients
[region
][client
] ||
181 /* Only allocate one slot for this client. */
182 interval
= NBR_OF_SLOTS
;
184 interval
= NBR_OF_SLOTS
/
185 arbiters
[arbiter
].requested_slots
[region
][client
];
188 while (pos
< NBR_OF_SLOTS
) {
199 for (slot
= 0; slot
< NBR_OF_SLOTS
; slot
++) {
201 * Allocate remaining slots in round-robin
202 * client-number order for active clients. For this
203 * pass, we ignore requested bandwidth and previous
208 while (!arbiters
[arbiter
].active_clients
[region
][client
]) {
209 client
= (client
+ 1) %
210 arbiters
[arbiter
].nbr_clients
;
215 client
= (client
+ 1) % arbiters
[arbiter
].nbr_clients
;
218 if (region
== EXT_REGION
)
219 REG_WR_INT_VECT(marb_foo
, regi_marb_foo
,
220 rw_l2_slots
, slot
, val
[slot
]);
221 else if (region
== INT_REGION
)
222 REG_WR_INT_VECT(marb_foo
, regi_marb_foo
,
223 rw_intm_slots
, slot
, val
[slot
]);
225 REG_WR_INT_VECT(marb_bar
, regi_marb_bar
,
226 rw_ddr2_slots
, slot
, val
[slot
]);
231 extern char _stext
[], _etext
[];
233 static void crisv32_arbiter_init(void)
235 static int initialized
;
243 * CPU caches are always set to active, but with zero
244 * bandwidth allocated. It should be ok to allocate zero
245 * bandwidth for the caches, because DMA for other channels
246 * will supposedly finish, once their programmed amount is
247 * done, and then the caches will get access according to the
248 * "fixed scheme" for unclaimed slots. Though, if for some
249 * use-case somewhere, there's a maximum CPU latency for
250 * e.g. some interrupt, we have to start allocating specific
251 * bandwidth for the CPU caches too.
253 arbiters
[0].active_clients
[EXT_REGION
][11] = 1;
254 arbiters
[0].active_clients
[EXT_REGION
][12] = 1;
255 crisv32_arbiter_config(0, EXT_REGION
, 0);
256 crisv32_arbiter_config(0, INT_REGION
, 0);
257 crisv32_arbiter_config(1, EXT_REGION
, 0);
259 if (request_irq(MEMARB_FOO_INTR_VECT
, crisv32_foo_arbiter_irq
,
261 printk(KERN_ERR
"Couldn't allocate arbiter IRQ\n");
263 if (request_irq(MEMARB_BAR_INTR_VECT
, crisv32_bar_arbiter_irq
,
265 printk(KERN_ERR
"Couldn't allocate arbiter IRQ\n");
267 #ifndef CONFIG_ETRAX_KGDB
268 /* Global watch for writes to kernel text segment. */
269 crisv32_arbiter_watch(virt_to_phys(_stext
), _etext
- _stext
,
270 MARB_CLIENTS(arbiter_all_clients
, arbiter_bar_all_clients
),
271 arbiter_all_write
, NULL
);
274 /* Set up max burst sizes by default */
275 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_h264_rd_burst
, 3);
276 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_h264_wr_burst
, 3);
277 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_ccd_burst
, 3);
278 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_vin_wr_burst
, 3);
279 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_vin_rd_burst
, 3);
280 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_sclr_rd_burst
, 3);
281 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_vout_burst
, 3);
282 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_sclr_fifo_burst
, 3);
283 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_l2cache_burst
, 3);
286 int crisv32_arbiter_allocate_bandwidth(int client
, int region
,
287 unsigned long bandwidth
)
290 int total_assigned
= 0;
291 int total_clients
= 0;
295 crisv32_arbiter_init();
297 if (client
& 0xffff0000) {
302 for (i
= 0; i
< arbiters
[arbiter
].nbr_clients
; i
++) {
303 total_assigned
+= arbiters
[arbiter
].requested_slots
[region
][i
];
304 total_clients
+= arbiters
[arbiter
].active_clients
[region
][i
];
307 /* Avoid division by 0 for 0-bandwidth requests. */
309 ? 0 : NBR_OF_SLOTS
/ (max_bandwidth
[region
] / bandwidth
);
312 * We make sure that there are enough slots only for non-zero
313 * requests. Requesting 0 bandwidth *may* allocate slots,
314 * though if all bandwidth is allocated, such a client won't
315 * get any and will have to rely on getting memory access
316 * according to the fixed scheme that's the default when one
317 * of the slot-allocated clients doesn't claim their slot.
319 if (total_assigned
+ req
> NBR_OF_SLOTS
)
322 arbiters
[arbiter
].active_clients
[region
][client
] = 1;
323 arbiters
[arbiter
].requested_slots
[region
][client
] = req
;
324 crisv32_arbiter_config(arbiter
, region
, NBR_OF_SLOTS
- total_assigned
);
326 /* Propagate allocation from foo to bar */
328 crisv32_arbiter_allocate_bandwidth(8 << 16,
329 EXT_REGION
, bandwidth
);
334 * Main entry for bandwidth deallocation.
336 * Strictly speaking, for a somewhat constant set of clients where
337 * each client gets a constant bandwidth and is just enabled or
338 * disabled (somewhat dynamically), no action is necessary here to
339 * avoid starvation for non-zero-allocation clients, as the allocated
340 * slots will just be unused. However, handing out those unused slots
341 * to active clients avoids needless latency if the "fixed scheme"
342 * would give unclaimed slots to an eager low-index client.
345 void crisv32_arbiter_deallocate_bandwidth(int client
, int region
)
348 int total_assigned
= 0;
351 if (client
& 0xffff0000)
354 arbiters
[arbiter
].requested_slots
[region
][client
] = 0;
355 arbiters
[arbiter
].active_clients
[region
][client
] = 0;
357 for (i
= 0; i
< arbiters
[arbiter
].nbr_clients
; i
++)
358 total_assigned
+= arbiters
[arbiter
].requested_slots
[region
][i
];
360 crisv32_arbiter_config(arbiter
, region
, NBR_OF_SLOTS
- total_assigned
);
363 int crisv32_arbiter_watch(unsigned long start
, unsigned long size
,
364 unsigned long clients
, unsigned long accesses
,
372 crisv32_arbiter_init();
374 if (start
> 0x80000000) {
375 printk(KERN_ERR
"Arbiter: %lX doesn't look like a "
376 "physical address", start
);
380 spin_lock(&arbiter_lock
);
382 if (clients
& 0xffff)
384 if (clients
& 0xffff0000)
387 for (arbiter
= 0; arbiter
< ARBITERS
; arbiter
++) {
391 for (i
= 0; i
< NUMBER_OF_BP
; i
++) {
392 if (!watches
[arbiter
][i
].used
) {
395 intr_mask
= REG_RD_INT(marb_bar
,
396 regi_marb_bar
, rw_intr_mask
);
398 intr_mask
= REG_RD_INT(marb_foo
,
399 regi_marb_foo
, rw_intr_mask
);
401 watches
[arbiter
][i
].used
= 1;
402 watches
[arbiter
][i
].start
= start
;
403 watches
[arbiter
][i
].end
= start
+ size
;
404 watches
[arbiter
][i
].cb
= cb
;
406 ret
|= (i
+ 1) << (arbiter
+ 8);
408 REG_WR_INT(marb_bar_bp
,
409 watches
[arbiter
][i
].instance
,
411 watches
[arbiter
][i
].start
);
412 REG_WR_INT(marb_bar_bp
,
413 watches
[arbiter
][i
].instance
,
415 watches
[arbiter
][i
].end
);
416 REG_WR_INT(marb_bar_bp
,
417 watches
[arbiter
][i
].instance
,
419 REG_WR_INT(marb_bar_bp
,
420 watches
[arbiter
][i
].instance
,
424 REG_WR_INT(marb_foo_bp
,
425 watches
[arbiter
][i
].instance
,
427 watches
[arbiter
][i
].start
);
428 REG_WR_INT(marb_foo_bp
,
429 watches
[arbiter
][i
].instance
,
431 watches
[arbiter
][i
].end
);
432 REG_WR_INT(marb_foo_bp
,
433 watches
[arbiter
][i
].instance
,
435 REG_WR_INT(marb_foo_bp
,
436 watches
[arbiter
][i
].instance
,
437 rw_clients
, clients
>> 16);
450 REG_WR_INT(marb_bar
, regi_marb_bar
,
451 rw_intr_mask
, intr_mask
);
453 REG_WR_INT(marb_foo
, regi_marb_foo
,
454 rw_intr_mask
, intr_mask
);
456 spin_unlock(&arbiter_lock
);
462 spin_unlock(&arbiter_lock
);
469 int crisv32_arbiter_unwatch(int id
)
474 crisv32_arbiter_init();
476 spin_lock(&arbiter_lock
);
478 for (arbiter
= 0; arbiter
< ARBITERS
; arbiter
++) {
482 intr_mask
= REG_RD_INT(marb_bar
, regi_marb_bar
,
485 intr_mask
= REG_RD_INT(marb_foo
, regi_marb_foo
,
488 id2
= (id
& (0xff << (arbiter
+ 8))) >> (arbiter
+ 8);
492 if ((id2
>= NUMBER_OF_BP
) || (!watches
[arbiter
][id2
].used
)) {
493 spin_unlock(&arbiter_lock
);
497 memset(&watches
[arbiter
][id2
], 0,
498 sizeof(struct crisv32_watch_entry
));
510 REG_WR_INT(marb_bar
, regi_marb_bar
, rw_intr_mask
,
513 REG_WR_INT(marb_foo
, regi_marb_foo
, rw_intr_mask
,
517 spin_unlock(&arbiter_lock
);
521 extern void show_registers(struct pt_regs
*regs
);
525 crisv32_foo_arbiter_irq(int irq
, void *dev_id
)
527 reg_marb_foo_r_masked_intr masked_intr
=
528 REG_RD(marb_foo
, regi_marb_foo
, r_masked_intr
);
529 reg_marb_foo_bp_r_brk_clients r_clients
;
530 reg_marb_foo_bp_r_brk_addr r_addr
;
531 reg_marb_foo_bp_r_brk_op r_op
;
532 reg_marb_foo_bp_r_brk_first_client r_first
;
533 reg_marb_foo_bp_r_brk_size r_size
;
534 reg_marb_foo_bp_rw_ack ack
= {0};
535 reg_marb_foo_rw_ack_intr ack_intr
= {
536 .bp0
= 1, .bp1
= 1, .bp2
= 1, .bp3
= 1
538 struct crisv32_watch_entry
*watch
;
539 unsigned arbiter
= (unsigned)dev_id
;
541 masked_intr
= REG_RD(marb_foo
, regi_marb_foo
, r_masked_intr
);
544 watch
= &watches
[arbiter
][0];
545 else if (masked_intr
.bp1
)
546 watch
= &watches
[arbiter
][1];
547 else if (masked_intr
.bp2
)
548 watch
= &watches
[arbiter
][2];
549 else if (masked_intr
.bp3
)
550 watch
= &watches
[arbiter
][3];
554 /* Retrieve all useful information and print it. */
555 r_clients
= REG_RD(marb_foo_bp
, watch
->instance
, r_brk_clients
);
556 r_addr
= REG_RD(marb_foo_bp
, watch
->instance
, r_brk_addr
);
557 r_op
= REG_RD(marb_foo_bp
, watch
->instance
, r_brk_op
);
558 r_first
= REG_RD(marb_foo_bp
, watch
->instance
, r_brk_first_client
);
559 r_size
= REG_RD(marb_foo_bp
, watch
->instance
, r_brk_size
);
561 printk(KERN_DEBUG
"Arbiter IRQ\n");
562 printk(KERN_DEBUG
"Clients %X addr %X op %X first %X size %X\n",
563 REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_clients
, r_clients
),
564 REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_addr
, r_addr
),
565 REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_op
, r_op
),
566 REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_first_client
, r_first
),
567 REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_size
, r_size
));
569 REG_WR(marb_foo_bp
, watch
->instance
, rw_ack
, ack
);
570 REG_WR(marb_foo
, regi_marb_foo
, rw_ack_intr
, ack_intr
);
572 printk(KERN_DEBUG
"IRQ occurred at %X\n", (unsigned)get_irq_regs());
581 crisv32_bar_arbiter_irq(int irq
, void *dev_id
)
583 reg_marb_bar_r_masked_intr masked_intr
=
584 REG_RD(marb_bar
, regi_marb_bar
, r_masked_intr
);
585 reg_marb_bar_bp_r_brk_clients r_clients
;
586 reg_marb_bar_bp_r_brk_addr r_addr
;
587 reg_marb_bar_bp_r_brk_op r_op
;
588 reg_marb_bar_bp_r_brk_first_client r_first
;
589 reg_marb_bar_bp_r_brk_size r_size
;
590 reg_marb_bar_bp_rw_ack ack
= {0};
591 reg_marb_bar_rw_ack_intr ack_intr
= {
592 .bp0
= 1, .bp1
= 1, .bp2
= 1, .bp3
= 1
594 struct crisv32_watch_entry
*watch
;
595 unsigned arbiter
= (unsigned)dev_id
;
597 masked_intr
= REG_RD(marb_bar
, regi_marb_bar
, r_masked_intr
);
600 watch
= &watches
[arbiter
][0];
601 else if (masked_intr
.bp1
)
602 watch
= &watches
[arbiter
][1];
603 else if (masked_intr
.bp2
)
604 watch
= &watches
[arbiter
][2];
605 else if (masked_intr
.bp3
)
606 watch
= &watches
[arbiter
][3];
610 /* Retrieve all useful information and print it. */
611 r_clients
= REG_RD(marb_bar_bp
, watch
->instance
, r_brk_clients
);
612 r_addr
= REG_RD(marb_bar_bp
, watch
->instance
, r_brk_addr
);
613 r_op
= REG_RD(marb_bar_bp
, watch
->instance
, r_brk_op
);
614 r_first
= REG_RD(marb_bar_bp
, watch
->instance
, r_brk_first_client
);
615 r_size
= REG_RD(marb_bar_bp
, watch
->instance
, r_brk_size
);
617 printk(KERN_DEBUG
"Arbiter IRQ\n");
618 printk(KERN_DEBUG
"Clients %X addr %X op %X first %X size %X\n",
619 REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_clients
, r_clients
),
620 REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_addr
, r_addr
),
621 REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_op
, r_op
),
622 REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_first_client
, r_first
),
623 REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_size
, r_size
));
625 REG_WR(marb_bar_bp
, watch
->instance
, rw_ack
, ack
);
626 REG_WR(marb_bar
, regi_marb_bar
, rw_ack_intr
, ack_intr
);
628 printk(KERN_DEBUG
"IRQ occurred at %X\n", (unsigned)get_irq_regs()->erp
);