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linux/arch/cris/arch-v32/mach-a3/arbiter.c

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/*
* Memory arbiter functions. Allocates bandwidth through the
* arbiter and sets up arbiter breakpoints.
*
* The algorithm first assigns slots to the clients that has specified
* bandwidth (e.g. ethernet) and then the remaining slots are divided
* on all the active clients.
*
* Copyright (c) 2004-2007 Axis Communications AB.
*
* The artpec-3 has two arbiters. The memory hierarchy looks like this:
*
*
* CPU DMAs
* | |
* | |
* -------------- ------------------
* | foo arbiter|----| Internal memory|
* -------------- ------------------
* |
* --------------
* | L2 cache |
* --------------
* |
* h264 etc |
* | |
* | |
* --------------
* | bar arbiter|
* --------------
* |
* ---------
* | SDRAM |
* ---------
*
*/
#include <hwregs/reg_map.h>
#include <hwregs/reg_rdwr.h>
#include <hwregs/marb_foo_defs.h>
#include <hwregs/marb_bar_defs.h>
#include <arbiter.h>
#include <hwregs/intr_vect.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <asm/io.h>
#include <asm/irq_regs.h>
#define D(x)
struct crisv32_watch_entry {
unsigned long instance;
watch_callback *cb;
unsigned long start;
unsigned long end;
int used;
};
#define NUMBER_OF_BP 4
#define SDRAM_BANDWIDTH 400000000
#define INTMEM_BANDWIDTH 400000000
#define NBR_OF_SLOTS 64
#define NBR_OF_REGIONS 2
#define NBR_OF_CLIENTS 15
#define ARBITERS 2
#define UNASSIGNED 100
struct arbiter {
unsigned long instance;
int nbr_regions;
int nbr_clients;
int requested_slots[NBR_OF_REGIONS][NBR_OF_CLIENTS];
int active_clients[NBR_OF_REGIONS][NBR_OF_CLIENTS];
};
static struct crisv32_watch_entry watches[ARBITERS][NUMBER_OF_BP] =
{
{
{regi_marb_foo_bp0},
{regi_marb_foo_bp1},
{regi_marb_foo_bp2},
{regi_marb_foo_bp3}
},
{
{regi_marb_bar_bp0},
{regi_marb_bar_bp1},
{regi_marb_bar_bp2},
{regi_marb_bar_bp3}
}
};
struct arbiter arbiters[ARBITERS] =
{
{ /* L2 cache arbiter */
.instance = regi_marb_foo,
.nbr_regions = 2,
.nbr_clients = 15
},
{ /* DDR2 arbiter */
.instance = regi_marb_bar,
.nbr_regions = 1,
.nbr_clients = 9
}
};
static int max_bandwidth[NBR_OF_REGIONS] = {SDRAM_BANDWIDTH, INTMEM_BANDWIDTH};
DEFINE_SPINLOCK(arbiter_lock);
static irqreturn_t
crisv32_foo_arbiter_irq(int irq, void *dev_id);
static irqreturn_t
crisv32_bar_arbiter_irq(int irq, void *dev_id);
/*
* "I'm the arbiter, I know the score.
* From square one I'll be watching all 64."
* (memory arbiter slots, that is)
*
* Or in other words:
* Program the memory arbiter slots for "region" according to what's
* in requested_slots[] and active_clients[], while minimizing
* latency. A caller may pass a non-zero positive amount for
* "unused_slots", which must then be the unallocated, remaining
* number of slots, free to hand out to any client.
*/
static void crisv32_arbiter_config(int arbiter, int region, int unused_slots)
{
int slot;
int client;
int interval = 0;
/*
* This vector corresponds to the hardware arbiter slots (see
* the hardware documentation for semantics). We initialize
* each slot with a suitable sentinel value outside the valid
* range {0 .. NBR_OF_CLIENTS - 1} and replace them with
* client indexes. Then it's fed to the hardware.
*/
s8 val[NBR_OF_SLOTS];
for (slot = 0; slot < NBR_OF_SLOTS; slot++)
val[slot] = -1;
for (client = 0; client < arbiters[arbiter].nbr_clients; client++) {
int pos;
/* Allocate the requested non-zero number of slots, but
* also give clients with zero-requests one slot each
* while stocks last. We do the latter here, in client
* order. This makes sure zero-request clients are the
* first to get to any spare slots, else those slots
* could, when bandwidth is allocated close to the limit,
* all be allocated to low-index non-zero-request clients
* in the default-fill loop below. Another positive but
* secondary effect is a somewhat better spread of the
* zero-bandwidth clients in the vector, avoiding some of
* the latency that could otherwise be caused by the
* partitioning of non-zero-bandwidth clients at low
* indexes and zero-bandwidth clients at high
* indexes. (Note that this spreading can only affect the
* unallocated bandwidth.) All the above only matters for
* memory-intensive situations, of course.
*/
if (!arbiters[arbiter].requested_slots[region][client]) {
/*
* Skip inactive clients. Also skip zero-slot
* allocations in this pass when there are no known
* free slots.
*/
if (!arbiters[arbiter].active_clients[region][client] ||
unused_slots <= 0)
continue;
unused_slots--;
/* Only allocate one slot for this client. */
interval = NBR_OF_SLOTS;
} else
interval = NBR_OF_SLOTS /
arbiters[arbiter].requested_slots[region][client];
pos = 0;
while (pos < NBR_OF_SLOTS) {
if (val[pos] >= 0)
pos++;
else {
val[pos] = client;
pos += interval;
}
}
}
client = 0;
for (slot = 0; slot < NBR_OF_SLOTS; slot++) {
/*
* Allocate remaining slots in round-robin
* client-number order for active clients. For this
* pass, we ignore requested bandwidth and previous
* allocations.
*/
if (val[slot] < 0) {
int first = client;
while (!arbiters[arbiter].active_clients[region][client]) {
client = (client + 1) %
arbiters[arbiter].nbr_clients;
if (client == first)
break;
}
val[slot] = client;
client = (client + 1) % arbiters[arbiter].nbr_clients;
}
if (arbiter == 0) {
if (region == EXT_REGION)
REG_WR_INT_VECT(marb_foo, regi_marb_foo,
rw_l2_slots, slot, val[slot]);
else if (region == INT_REGION)
REG_WR_INT_VECT(marb_foo, regi_marb_foo,
rw_intm_slots, slot, val[slot]);
} else {
REG_WR_INT_VECT(marb_bar, regi_marb_bar,
rw_ddr2_slots, slot, val[slot]);
}
}
}
extern char _stext, _etext;
static void crisv32_arbiter_init(void)
{
static int initialized;
if (initialized)
return;
initialized = 1;
/*
* CPU caches are always set to active, but with zero
* bandwidth allocated. It should be ok to allocate zero
* bandwidth for the caches, because DMA for other channels
* will supposedly finish, once their programmed amount is
* done, and then the caches will get access according to the
* "fixed scheme" for unclaimed slots. Though, if for some
* use-case somewhere, there's a maximum CPU latency for
* e.g. some interrupt, we have to start allocating specific
* bandwidth for the CPU caches too.
*/
arbiters[0].active_clients[EXT_REGION][11] = 1;
arbiters[0].active_clients[EXT_REGION][12] = 1;
crisv32_arbiter_config(0, EXT_REGION, 0);
crisv32_arbiter_config(0, INT_REGION, 0);
crisv32_arbiter_config(1, EXT_REGION, 0);
if (request_irq(MEMARB_FOO_INTR_VECT, crisv32_foo_arbiter_irq,
IRQF_DISABLED, "arbiter", NULL))
printk(KERN_ERR "Couldn't allocate arbiter IRQ\n");
if (request_irq(MEMARB_BAR_INTR_VECT, crisv32_bar_arbiter_irq,
IRQF_DISABLED, "arbiter", NULL))
printk(KERN_ERR "Couldn't allocate arbiter IRQ\n");
#ifndef CONFIG_ETRAX_KGDB
/* Global watch for writes to kernel text segment. */
crisv32_arbiter_watch(virt_to_phys(&_stext), &_etext - &_stext,
MARB_CLIENTS(arbiter_all_clients, arbiter_bar_all_clients),
arbiter_all_write, NULL);
#endif
/* Set up max burst sizes by default */
REG_WR_INT(marb_bar, regi_marb_bar, rw_h264_rd_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_h264_wr_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_ccd_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_vin_wr_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_vin_rd_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_sclr_rd_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_vout_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_sclr_fifo_burst, 3);
REG_WR_INT(marb_bar, regi_marb_bar, rw_l2cache_burst, 3);
}
int crisv32_arbiter_allocate_bandwidth(int client, int region,
unsigned long bandwidth)
{
int i;
int total_assigned = 0;
int total_clients = 0;
int req;
int arbiter = 0;
crisv32_arbiter_init();
if (client & 0xffff0000) {
arbiter = 1;
client >>= 16;
}
for (i = 0; i < arbiters[arbiter].nbr_clients; i++) {
total_assigned += arbiters[arbiter].requested_slots[region][i];
total_clients += arbiters[arbiter].active_clients[region][i];
}
/* Avoid division by 0 for 0-bandwidth requests. */
req = bandwidth == 0
? 0 : NBR_OF_SLOTS / (max_bandwidth[region] / bandwidth);
/*
* We make sure that there are enough slots only for non-zero
* requests. Requesting 0 bandwidth *may* allocate slots,
* though if all bandwidth is allocated, such a client won't
* get any and will have to rely on getting memory access
* according to the fixed scheme that's the default when one
* of the slot-allocated clients doesn't claim their slot.
*/
if (total_assigned + req > NBR_OF_SLOTS)
return -ENOMEM;
arbiters[arbiter].active_clients[region][client] = 1;
arbiters[arbiter].requested_slots[region][client] = req;
crisv32_arbiter_config(arbiter, region, NBR_OF_SLOTS - total_assigned);
/* Propagate allocation from foo to bar */
if (arbiter == 0)
crisv32_arbiter_allocate_bandwidth(8 << 16,
EXT_REGION, bandwidth);
return 0;
}
/*
* Main entry for bandwidth deallocation.
*
* Strictly speaking, for a somewhat constant set of clients where
* each client gets a constant bandwidth and is just enabled or
* disabled (somewhat dynamically), no action is necessary here to
* avoid starvation for non-zero-allocation clients, as the allocated
* slots will just be unused. However, handing out those unused slots
* to active clients avoids needless latency if the "fixed scheme"
* would give unclaimed slots to an eager low-index client.
*/
void crisv32_arbiter_deallocate_bandwidth(int client, int region)
{
int i;
int total_assigned = 0;
int arbiter = 0;
if (client & 0xffff0000)
arbiter = 1;
arbiters[arbiter].requested_slots[region][client] = 0;
arbiters[arbiter].active_clients[region][client] = 0;
for (i = 0; i < arbiters[arbiter].nbr_clients; i++)
total_assigned += arbiters[arbiter].requested_slots[region][i];
crisv32_arbiter_config(arbiter, region, NBR_OF_SLOTS - total_assigned);
}
int crisv32_arbiter_watch(unsigned long start, unsigned long size,
unsigned long clients, unsigned long accesses,
watch_callback *cb)
{
int i;
int arbiter;
int used[2];
int ret = 0;
crisv32_arbiter_init();
if (start > 0x80000000) {
printk(KERN_ERR "Arbiter: %lX doesn't look like a "
"physical address", start);
return -EFAULT;
}
spin_lock(&arbiter_lock);
if (clients & 0xffff)
used[0] = 1;
if (clients & 0xffff0000)
used[1] = 1;
for (arbiter = 0; arbiter < ARBITERS; arbiter++) {
if (!used[arbiter])
continue;
for (i = 0; i < NUMBER_OF_BP; i++) {
if (!watches[arbiter][i].used) {
unsigned intr_mask;
if (arbiter)
intr_mask = REG_RD_INT(marb_bar,
regi_marb_bar, rw_intr_mask);
else
intr_mask = REG_RD_INT(marb_foo,
regi_marb_foo, rw_intr_mask);
watches[arbiter][i].used = 1;
watches[arbiter][i].start = start;
watches[arbiter][i].end = start + size;
watches[arbiter][i].cb = cb;
ret |= (i + 1) << (arbiter + 8);
if (arbiter) {
REG_WR_INT(marb_bar_bp,
watches[arbiter][i].instance,
rw_first_addr,
watches[arbiter][i].start);
REG_WR_INT(marb_bar_bp,
watches[arbiter][i].instance,
rw_last_addr,
watches[arbiter][i].end);
REG_WR_INT(marb_bar_bp,
watches[arbiter][i].instance,
rw_op, accesses);
REG_WR_INT(marb_bar_bp,
watches[arbiter][i].instance,
rw_clients,
clients & 0xffff);
} else {
REG_WR_INT(marb_foo_bp,
watches[arbiter][i].instance,
rw_first_addr,
watches[arbiter][i].start);
REG_WR_INT(marb_foo_bp,
watches[arbiter][i].instance,
rw_last_addr,
watches[arbiter][i].end);
REG_WR_INT(marb_foo_bp,
watches[arbiter][i].instance,
rw_op, accesses);
REG_WR_INT(marb_foo_bp,
watches[arbiter][i].instance,
rw_clients, clients >> 16);
}
if (i == 0)
intr_mask |= 1;
else if (i == 1)
intr_mask |= 2;
else if (i == 2)
intr_mask |= 4;
else if (i == 3)
intr_mask |= 8;
if (arbiter)
REG_WR_INT(marb_bar, regi_marb_bar,
rw_intr_mask, intr_mask);
else
REG_WR_INT(marb_foo, regi_marb_foo,
rw_intr_mask, intr_mask);
spin_unlock(&arbiter_lock);
break;
}
}
}
spin_unlock(&arbiter_lock);
if (ret)
return ret;
else
return -ENOMEM;
}
int crisv32_arbiter_unwatch(int id)
{
int arbiter;
int intr_mask;
crisv32_arbiter_init();
spin_lock(&arbiter_lock);
for (arbiter = 0; arbiter < ARBITERS; arbiter++) {
int id2;
if (arbiter)
intr_mask = REG_RD_INT(marb_bar, regi_marb_bar,
rw_intr_mask);
else
intr_mask = REG_RD_INT(marb_foo, regi_marb_foo,
rw_intr_mask);
id2 = (id & (0xff << (arbiter + 8))) >> (arbiter + 8);
if (id2 == 0)
continue;
id2--;
if ((id2 >= NUMBER_OF_BP) || (!watches[arbiter][id2].used)) {
spin_unlock(&arbiter_lock);
return -EINVAL;
}
memset(&watches[arbiter][id2], 0,
sizeof(struct crisv32_watch_entry));
if (id2 == 0)
intr_mask &= ~1;
else if (id2 == 1)
intr_mask &= ~2;
else if (id2 == 2)
intr_mask &= ~4;
else if (id2 == 3)
intr_mask &= ~8;
if (arbiter)
REG_WR_INT(marb_bar, regi_marb_bar, rw_intr_mask,
intr_mask);
else
REG_WR_INT(marb_foo, regi_marb_foo, rw_intr_mask,
intr_mask);
}
spin_unlock(&arbiter_lock);
return 0;
}
extern void show_registers(struct pt_regs *regs);
static irqreturn_t
crisv32_foo_arbiter_irq(int irq, void *dev_id)
{
reg_marb_foo_r_masked_intr masked_intr =
REG_RD(marb_foo, regi_marb_foo, r_masked_intr);
reg_marb_foo_bp_r_brk_clients r_clients;
reg_marb_foo_bp_r_brk_addr r_addr;
reg_marb_foo_bp_r_brk_op r_op;
reg_marb_foo_bp_r_brk_first_client r_first;
reg_marb_foo_bp_r_brk_size r_size;
reg_marb_foo_bp_rw_ack ack = {0};
reg_marb_foo_rw_ack_intr ack_intr = {
.bp0 = 1, .bp1 = 1, .bp2 = 1, .bp3 = 1
};
struct crisv32_watch_entry *watch;
unsigned arbiter = (unsigned)dev_id;
masked_intr = REG_RD(marb_foo, regi_marb_foo, r_masked_intr);
if (masked_intr.bp0)
watch = &watches[arbiter][0];
else if (masked_intr.bp1)
watch = &watches[arbiter][1];
else if (masked_intr.bp2)
watch = &watches[arbiter][2];
else if (masked_intr.bp3)
watch = &watches[arbiter][3];
else
return IRQ_NONE;
/* Retrieve all useful information and print it. */
r_clients = REG_RD(marb_foo_bp, watch->instance, r_brk_clients);
r_addr = REG_RD(marb_foo_bp, watch->instance, r_brk_addr);
r_op = REG_RD(marb_foo_bp, watch->instance, r_brk_op);
r_first = REG_RD(marb_foo_bp, watch->instance, r_brk_first_client);
r_size = REG_RD(marb_foo_bp, watch->instance, r_brk_size);
printk(KERN_DEBUG "Arbiter IRQ\n");
printk(KERN_DEBUG "Clients %X addr %X op %X first %X size %X\n",
REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_clients, r_clients),
REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_addr, r_addr),
REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_op, r_op),
REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_first_client, r_first),
REG_TYPE_CONV(int, reg_marb_foo_bp_r_brk_size, r_size));
REG_WR(marb_foo_bp, watch->instance, rw_ack, ack);
REG_WR(marb_foo, regi_marb_foo, rw_ack_intr, ack_intr);
printk(KERN_DEBUG "IRQ occured at %X\n", (unsigned)get_irq_regs());
if (watch->cb)
watch->cb();
return IRQ_HANDLED;
}
static irqreturn_t
crisv32_bar_arbiter_irq(int irq, void *dev_id)
{
reg_marb_bar_r_masked_intr masked_intr =
REG_RD(marb_bar, regi_marb_bar, r_masked_intr);
reg_marb_bar_bp_r_brk_clients r_clients;
reg_marb_bar_bp_r_brk_addr r_addr;
reg_marb_bar_bp_r_brk_op r_op;
reg_marb_bar_bp_r_brk_first_client r_first;
reg_marb_bar_bp_r_brk_size r_size;
reg_marb_bar_bp_rw_ack ack = {0};
reg_marb_bar_rw_ack_intr ack_intr = {
.bp0 = 1, .bp1 = 1, .bp2 = 1, .bp3 = 1
};
struct crisv32_watch_entry *watch;
unsigned arbiter = (unsigned)dev_id;
masked_intr = REG_RD(marb_bar, regi_marb_bar, r_masked_intr);
if (masked_intr.bp0)
watch = &watches[arbiter][0];
else if (masked_intr.bp1)
watch = &watches[arbiter][1];
else if (masked_intr.bp2)
watch = &watches[arbiter][2];
else if (masked_intr.bp3)
watch = &watches[arbiter][3];
else
return IRQ_NONE;
/* Retrieve all useful information and print it. */
r_clients = REG_RD(marb_bar_bp, watch->instance, r_brk_clients);
r_addr = REG_RD(marb_bar_bp, watch->instance, r_brk_addr);
r_op = REG_RD(marb_bar_bp, watch->instance, r_brk_op);
r_first = REG_RD(marb_bar_bp, watch->instance, r_brk_first_client);
r_size = REG_RD(marb_bar_bp, watch->instance, r_brk_size);
printk(KERN_DEBUG "Arbiter IRQ\n");
printk(KERN_DEBUG "Clients %X addr %X op %X first %X size %X\n",
REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_clients, r_clients),
REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_addr, r_addr),
REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_op, r_op),
REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_first_client, r_first),
REG_TYPE_CONV(int, reg_marb_bar_bp_r_brk_size, r_size));
REG_WR(marb_bar_bp, watch->instance, rw_ack, ack);
REG_WR(marb_bar, regi_marb_bar, rw_ack_intr, ack_intr);
printk(KERN_DEBUG "IRQ occured at %X\n", (unsigned)get_irq_regs()->erp);
if (watch->cb)
watch->cb();
return IRQ_HANDLED;
}
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