arch/cris/arch-v32/kernel/arbiter.c

   1 /*
   2  * Memory arbiter functions. Allocates bandwith through the
   3  * arbiter and sets up arbiter breakpoints.
   4  *
   5  * The algorithm first assigns slots to the clients that has specified
   6  * bandwith (e.g. ethernet) and then the remaining slots are divided
   7  * on all the active clients.
   8  *
   9  * Copyright (c) 2004, 2005 Axis Communications AB.
  10  */
  11
  12 #include <linux/config.h>
  13 #include <asm/arch/hwregs/reg_map.h>
  14 #include <asm/arch/hwregs/reg_rdwr.h>
  15 #include <asm/arch/hwregs/marb_defs.h>
  16 #include <asm/arch/arbiter.h>
  17 #include <asm/arch/hwregs/intr_vect.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/signal.h>
  20 #include <linux/errno.h>
  21 #include <linux/spinlock.h>
  22 #include <asm/io.h>
  23
  24 struct crisv32_watch_entry
  25 {
  26   unsigned long instance;
  27   watch_callback* cb;
  28   unsigned long start;
  29   unsigned long end;
  30   int used;
  31 };
  32
  33 #define NUMBER_OF_BP 4
  34 #define NBR_OF_CLIENTS 14
  35 #define NBR_OF_SLOTS 64
  36 #define SDRAM_BANDWIDTH 100000000 /* Some kind of expected value */
  37 #define INTMEM_BANDWIDTH 400000000
  38 #define NBR_OF_REGIONS 2
  39
  40 static struct crisv32_watch_entry watches[NUMBER_OF_BP] =
  41 {
  42   {regi_marb_bp0},
  43   {regi_marb_bp1},
  44   {regi_marb_bp2},
  45   {regi_marb_bp3}
  46 };
  47
  48 static int requested_slots[NBR_OF_REGIONS][NBR_OF_CLIENTS];
  49 static int active_clients[NBR_OF_REGIONS][NBR_OF_CLIENTS];
  50 static int max_bandwidth[NBR_OF_REGIONS] = {SDRAM_BANDWIDTH, INTMEM_BANDWIDTH};
  51
  52 DEFINE_SPINLOCK(arbiter_lock);
  53
  54 static irqreturn_t
  55 crisv32_arbiter_irq(int irq, void* dev_id, struct pt_regs* regs);
  56
  57 static void crisv32_arbiter_config(int region)
  58 {
  59         int slot;
  60         int client;
  61         int interval = 0;
  62         int val[NBR_OF_SLOTS];
  63
  64         for (slot = 0; slot < NBR_OF_SLOTS; slot++)
  65             val[slot] = NBR_OF_CLIENTS + 1;
  66
  67         for (client = 0; client < NBR_OF_CLIENTS; client++)
  68         {
  69             int pos;
  70             if (!requested_slots[region][client])
  71                continue;
  72             interval = NBR_OF_SLOTS / requested_slots[region][client];
  73             pos = 0;
  74             while (pos < NBR_OF_SLOTS)
  75             {
  76                 if (val[pos] != NBR_OF_CLIENTS + 1)
  77                    pos++;
  78                 else
  79                 {
  80                         val[pos] = client;
  81                         pos += interval;
  82                 }
  83             }
  84         }
  85
  86         client = 0;
  87         for (slot = 0; slot < NBR_OF_SLOTS; slot++)
  88         {
  89                 if (val[slot] == NBR_OF_CLIENTS + 1)
  90                 {
  91                         int first = client;
  92                         while(!active_clients[region][client]) {
  93                                 client = (client + 1) % NBR_OF_CLIENTS;
  94                                 if (client == first)
  95                                    break;
  96                         }
  97                         val[slot] = client;
  98                         client = (client + 1) % NBR_OF_CLIENTS;
  99                 }
 100                 if (region == EXT_REGION)
 101                    REG_WR_INT_VECT(marb, regi_marb, rw_ext_slots, slot, val[slot]);
 102                 else if (region == INT_REGION)
 103                    REG_WR_INT_VECT(marb, regi_marb, rw_int_slots, slot, val[slot]);
 104         }
 105 }
 106
 107 extern char _stext, _etext;
 108
 109 static void crisv32_arbiter_init(void)
 110 {
 111         static int initialized = 0;
 112
 113         if (initialized)
 114                 return;
 115
 116         initialized = 1;
 117
 118         /* CPU caches are active. */
 119         active_clients[EXT_REGION][10] = active_clients[EXT_REGION][11] = 1;
 120         crisv32_arbiter_config(EXT_REGION);
 121         crisv32_arbiter_config(INT_REGION);
 122
 123         if (request_irq(MEMARB_INTR_VECT, crisv32_arbiter_irq, SA_INTERRUPT,
 124                         "arbiter", NULL))
 125                 printk(KERN_ERR "Couldn't allocate arbiter IRQ\n");
 126
 127 #ifndef CONFIG_ETRAX_KGDB
 128         /* Global watch for writes to kernel text segment. */
 129         crisv32_arbiter_watch(virt_to_phys(&_stext), &_etext - &_stext,
 130                               arbiter_all_clients, arbiter_all_write, NULL);
 131 #endif
 132 }
 133
 134
 135
 136 int crisv32_arbiter_allocate_bandwith(int client, int region,
 137                                       unsigned long bandwidth)
 138 {
 139         int i;
 140         int total_assigned = 0;
 141         int total_clients = 0;
 142         int req;
 143
 144         crisv32_arbiter_init();
 145
 146         for (i = 0; i < NBR_OF_CLIENTS; i++)
 147         {
 148                 total_assigned += requested_slots[region][i];
 149                 total_clients += active_clients[region][i];
 150         }
 151         req = NBR_OF_SLOTS / (max_bandwidth[region] / bandwidth);
 152
 153         if (total_assigned + total_clients + req + 1 > NBR_OF_SLOTS)
 154            return -ENOMEM;
 155
 156         active_clients[region][client] = 1;
 157         requested_slots[region][client] = req;
 158         crisv32_arbiter_config(region);
 159
 160         return 0;
 161 }
 162
 163 int crisv32_arbiter_watch(unsigned long start, unsigned long size,
 164                           unsigned long clients, unsigned long accesses,
 165                           watch_callback* cb)
 166 {
 167         int i;
 168
 169         crisv32_arbiter_init();
 170
 171         if (start > 0x80000000) {
 172                 printk("Arbiter: %lX doesn't look like a physical address", start);
 173                 return -EFAULT;
 174         }
 175
 176         spin_lock(&arbiter_lock);
 177
 178         for (i = 0; i < NUMBER_OF_BP; i++) {
 179                 if (!watches[i].used) {
 180                         reg_marb_rw_intr_mask intr_mask = REG_RD(marb, regi_marb, rw_intr_mask);
 181
 182                         watches[i].used = 1;
 183                         watches[i].start = start;
 184                         watches[i].end = start + size;
 185                         watches[i].cb = cb;
 186
 187                         REG_WR_INT(marb_bp, watches[i].instance, rw_first_addr, watches[i].start);
 188                         REG_WR_INT(marb_bp, watches[i].instance, rw_last_addr, watches[i].end);
 189                         REG_WR_INT(marb_bp, watches[i].instance, rw_op, accesses);
 190                         REG_WR_INT(marb_bp, watches[i].instance, rw_clients, clients);
 191
 192                         if (i == 0)
 193                                 intr_mask.bp0 = regk_marb_yes;
 194                         else if (i == 1)
 195                                 intr_mask.bp1 = regk_marb_yes;
 196                         else if (i == 2)
 197                                 intr_mask.bp2 = regk_marb_yes;
 198                         else if (i == 3)
 199                                 intr_mask.bp3 = regk_marb_yes;
 200
 201                         REG_WR(marb, regi_marb, rw_intr_mask, intr_mask);
 202                         spin_unlock(&arbiter_lock);
 203
 204                         return i;
 205                 }
 206         }
 207         spin_unlock(&arbiter_lock);
 208         return -ENOMEM;
 209 }
 210
 211 int crisv32_arbiter_unwatch(int id)
 212 {
 213         reg_marb_rw_intr_mask intr_mask = REG_RD(marb, regi_marb, rw_intr_mask);
 214
 215         crisv32_arbiter_init();
 216
 217         spin_lock(&arbiter_lock);
 218
 219         if ((id < 0) || (id >= NUMBER_OF_BP) || (!watches[id].used)) {
 220                 spin_unlock(&arbiter_lock);
 221                 return -EINVAL;
 222         }
 223
 224         memset(&watches[id], 0, sizeof(struct crisv32_watch_entry));
 225
 226         if (id == 0)
 227                 intr_mask.bp0 = regk_marb_no;
 228         else if (id == 1)
 229                 intr_mask.bp2 = regk_marb_no;
 230         else if (id == 2)
 231                 intr_mask.bp2 = regk_marb_no;
 232         else if (id == 3)
 233                 intr_mask.bp3 = regk_marb_no;
 234
 235         REG_WR(marb, regi_marb, rw_intr_mask, intr_mask);
 236
 237         spin_unlock(&arbiter_lock);
 238         return 0;
 239 }
 240
 241 extern void show_registers(struct pt_regs *regs);
 242
 243 static irqreturn_t
 244 crisv32_arbiter_irq(int irq, void* dev_id, struct pt_regs* regs)
 245 {
 246         reg_marb_r_masked_intr masked_intr = REG_RD(marb, regi_marb, r_masked_intr);
 247         reg_marb_bp_r_brk_clients r_clients;
 248         reg_marb_bp_r_brk_addr r_addr;
 249         reg_marb_bp_r_brk_op r_op;
 250         reg_marb_bp_r_brk_first_client r_first;
 251         reg_marb_bp_r_brk_size r_size;
 252         reg_marb_bp_rw_ack ack = {0};
 253         reg_marb_rw_ack_intr ack_intr = {.bp0=1,.bp1=1,.bp2=1,.bp3=1};
 254         struct crisv32_watch_entry* watch;
 255
 256         if (masked_intr.bp0) {
 257                 watch = &watches[0];
 258                 ack_intr.bp0 = regk_marb_yes;
 259         } else if (masked_intr.bp1) {
 260                 watch = &watches[1];
 261                 ack_intr.bp1 = regk_marb_yes;
 262         } else if (masked_intr.bp2) {
 263                 watch = &watches[2];
 264                 ack_intr.bp2 = regk_marb_yes;
 265         } else if (masked_intr.bp3) {
 266                 watch = &watches[3];
 267                 ack_intr.bp3 = regk_marb_yes;
 268         } else {
 269                 return IRQ_NONE;
 270         }
 271
 272         /* Retrieve all useful information and print it. */
 273         r_clients = REG_RD(marb_bp, watch->instance, r_brk_clients);
 274         r_addr = REG_RD(marb_bp, watch->instance, r_brk_addr);
 275         r_op = REG_RD(marb_bp, watch->instance, r_brk_op);
 276         r_first = REG_RD(marb_bp, watch->instance, r_brk_first_client);
 277         r_size = REG_RD(marb_bp, watch->instance, r_brk_size);
 278
 279         printk("Arbiter IRQ\n");
 280         printk("Clients %X addr %X op %X first %X size %X\n",
 281                REG_TYPE_CONV(int, reg_marb_bp_r_brk_clients, r_clients),
 282                REG_TYPE_CONV(int, reg_marb_bp_r_brk_addr, r_addr),
 283                REG_TYPE_CONV(int, reg_marb_bp_r_brk_op, r_op),
 284                REG_TYPE_CONV(int, reg_marb_bp_r_brk_first_client, r_first),
 285                REG_TYPE_CONV(int, reg_marb_bp_r_brk_size, r_size));
 286
 287         REG_WR(marb_bp, watch->instance, rw_ack, ack);
 288         REG_WR(marb, regi_marb, rw_ack_intr, ack_intr);
 289
 290         printk("IRQ occured at %lX\n", regs->erp);
 291
 292         if (watch->cb)
 293                 watch->cb();
 294
 295
 296         return IRQ_HANDLED;
 297 }