kernel/arch/powerpc/sysdev/xics/icp-native.c

   1 /*
   2  * Copyright 2011 IBM Corporation.
   3  *
   4  *  This program is free software; you can redistribute it and/or
   5  *  modify it under the terms of the GNU General Public License
   6  *  as published by the Free Software Foundation; either version
   7  *  2 of the License, or (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/irq.h>
  14 #include <linux/smp.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/init.h>
  17 #include <linux/cpu.h>
  18 #include <linux/of.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/module.h>
  21
  22 #include <asm/prom.h>
  23 #include <asm/io.h>
  24 #include <asm/smp.h>
  25 #include <asm/irq.h>
  26 #include <asm/errno.h>
  27 #include <asm/xics.h>
  28 #include <asm/kvm_ppc.h>
  29 #include <asm/dbell.h>
  30
  31 struct icp_ipl {
  32         union {
  33                 u32 word;
  34                 u8 bytes[4];
  35         } xirr_poll;
  36         union {
  37                 u32 word;
  38                 u8 bytes[4];
  39         } xirr;
  40         u32 dummy;
  41         union {
  42                 u32 word;
  43                 u8 bytes[4];
  44         } qirr;
  45         u32 link_a;
  46         u32 link_b;
  47         u32 link_c;
  48 };
  49
  50 static struct icp_ipl __iomem *icp_native_regs[NR_CPUS];
  51
  52 static inline unsigned int icp_native_get_xirr(void)
  53 {
  54         int cpu = smp_processor_id();
  55         unsigned int xirr;
  56
  57         /* Handled an interrupt latched by KVM */
  58         xirr = kvmppc_get_xics_latch();
  59         if (xirr)
  60                 return xirr;
  61
  62         return in_be32(&icp_native_regs[cpu]->xirr.word);
  63 }
  64
  65 static inline void icp_native_set_xirr(unsigned int value)
  66 {
  67         int cpu = smp_processor_id();
  68
  69         out_be32(&icp_native_regs[cpu]->xirr.word, value);
  70 }
  71
  72 static inline void icp_native_set_cppr(u8 value)
  73 {
  74         int cpu = smp_processor_id();
  75
  76         out_8(&icp_native_regs[cpu]->xirr.bytes[0], value);
  77 }
  78
  79 static inline void icp_native_set_qirr(int n_cpu, u8 value)
  80 {
  81         out_8(&icp_native_regs[n_cpu]->qirr.bytes[0], value);
  82 }
  83
  84 static void icp_native_set_cpu_priority(unsigned char cppr)
  85 {
  86         xics_set_base_cppr(cppr);
  87         icp_native_set_cppr(cppr);
  88         iosync();
  89 }
  90
  91 void icp_native_eoi(struct irq_data *d)
  92 {
  93         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  94
  95         iosync();
  96         icp_native_set_xirr((xics_pop_cppr() << 24) | hw_irq);
  97 }
  98
  99 static void icp_native_teardown_cpu(void)
 100 {
 101         int cpu = smp_processor_id();
 102
 103         /* Clear any pending IPI */
 104         icp_native_set_qirr(cpu, 0xff);
 105 }
 106
 107 static void icp_native_flush_ipi(void)
 108 {
 109         /* We take the ipi irq but and never return so we
 110          * need to EOI the IPI, but want to leave our priority 0
 111          *
 112          * should we check all the other interrupts too?
 113          * should we be flagging idle loop instead?
 114          * or creating some task to be scheduled?
 115          */
 116
 117         icp_native_set_xirr((0x00 << 24) | XICS_IPI);
 118 }
 119
 120 static unsigned int icp_native_get_irq(void)
 121 {
 122         unsigned int xirr = icp_native_get_xirr();
 123         unsigned int vec = xirr & 0x00ffffff;
 124         unsigned int irq;
 125
 126         if (vec == XICS_IRQ_SPURIOUS)
 127                 return NO_IRQ;
 128
 129         irq = irq_find_mapping(xics_host, vec);
 130         if (likely(irq != NO_IRQ)) {
 131                 xics_push_cppr(vec);
 132                 return irq;
 133         }
 134
 135         /* We don't have a linux mapping, so have rtas mask it. */
 136         xics_mask_unknown_vec(vec);
 137
 138         /* We might learn about it later, so EOI it */
 139         icp_native_set_xirr(xirr);
 140
 141         return NO_IRQ;
 142 }
 143
 144 #ifdef CONFIG_SMP
 145
 146 static void icp_native_cause_ipi(int cpu, unsigned long data)
 147 {
 148         kvmppc_set_host_ipi(cpu, 1);
 149 #ifdef CONFIG_PPC_DOORBELL
 150         if (cpu_has_feature(CPU_FTR_DBELL)) {
 151                 if (cpumask_test_cpu(cpu, cpu_sibling_mask(get_cpu()))) {
 152                         doorbell_cause_ipi(cpu, data);
 153                         put_cpu();
 154                         return;
 155                 }
 156                 put_cpu();
 157         }
 158 #endif
 159         icp_native_set_qirr(cpu, IPI_PRIORITY);
 160 }
 161
 162 /*
 163  * Called when an interrupt is received on an off-line CPU to
 164  * clear the interrupt, so that the CPU can go back to nap mode.
 165  */
 166 void icp_native_flush_interrupt(void)
 167 {
 168         unsigned int xirr = icp_native_get_xirr();
 169         unsigned int vec = xirr & 0x00ffffff;
 170
 171         if (vec == XICS_IRQ_SPURIOUS)
 172                 return;
 173         if (vec == XICS_IPI) {
 174                 /* Clear pending IPI */
 175                 int cpu = smp_processor_id();
 176                 kvmppc_set_host_ipi(cpu, 0);
 177                 icp_native_set_qirr(cpu, 0xff);
 178         } else {
 179                 pr_err("XICS: hw interrupt 0x%x to offline cpu, disabling\n",
 180                        vec);
 181                 xics_mask_unknown_vec(vec);
 182         }
 183         /* EOI the interrupt */
 184         icp_native_set_xirr(xirr);
 185 }
 186
 187 void xics_wake_cpu(int cpu)
 188 {
 189         icp_native_set_qirr(cpu, IPI_PRIORITY);
 190 }
 191 EXPORT_SYMBOL_GPL(xics_wake_cpu);
 192
 193 static irqreturn_t icp_native_ipi_action(int irq, void *dev_id)
 194 {
 195         int cpu = smp_processor_id();
 196
 197         kvmppc_set_host_ipi(cpu, 0);
 198         icp_native_set_qirr(cpu, 0xff);
 199
 200         return smp_ipi_demux();
 201 }
 202
 203 #endif /* CONFIG_SMP */
 204
 205 static int __init icp_native_map_one_cpu(int hw_id, unsigned long addr,
 206                                          unsigned long size)
 207 {
 208         char *rname;
 209         int i, cpu = -1;
 210
 211         /* This may look gross but it's good enough for now, we don't quite
 212          * have a hard -> linux processor id matching.
 213          */
 214         for_each_possible_cpu(i) {
 215                 if (!cpu_present(i))
 216                         continue;
 217                 if (hw_id == get_hard_smp_processor_id(i)) {
 218                         cpu = i;
 219                         break;
 220                 }
 221         }
 222
 223         /* Fail, skip that CPU. Don't print, it's normal, some XICS come up
 224          * with way more entries in there than you have CPUs
 225          */
 226         if (cpu == -1)
 227                 return 0;
 228
 229         rname = kasprintf(GFP_KERNEL, "CPU %d [0x%x] Interrupt Presentation",
 230                           cpu, hw_id);
 231
 232         if (!request_mem_region(addr, size, rname)) {
 233                 pr_warning("icp_native: Could not reserve ICP MMIO"
 234                            " for CPU %d, interrupt server #0x%x\n",
 235                            cpu, hw_id);
 236                 return -EBUSY;
 237         }
 238
 239         icp_native_regs[cpu] = ioremap(addr, size);
 240         kvmppc_set_xics_phys(cpu, addr);
 241         if (!icp_native_regs[cpu]) {
 242                 pr_warning("icp_native: Failed ioremap for CPU %d, "
 243                            "interrupt server #0x%x, addr %#lx\n",
 244                            cpu, hw_id, addr);
 245                 release_mem_region(addr, size);
 246                 return -ENOMEM;
 247         }
 248         return 0;
 249 }
 250
 251 static int __init icp_native_init_one_node(struct device_node *np,
 252                                            unsigned int *indx)
 253 {
 254         unsigned int ilen;
 255         const __be32 *ireg;
 256         int i;
 257         int reg_tuple_size;
 258         int num_servers = 0;
 259
 260         /* This code does the theorically broken assumption that the interrupt
 261          * server numbers are the same as the hard CPU numbers.
 262          * This happens to be the case so far but we are playing with fire...
 263          * should be fixed one of these days. -BenH.
 264          */
 265         ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
 266
 267         /* Do that ever happen ? we'll know soon enough... but even good'old
 268          * f80 does have that property ..
 269          */
 270         WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
 271
 272         if (ireg) {
 273                 *indx = of_read_number(ireg, 1);
 274                 if (ilen >= 2*sizeof(u32))
 275                         num_servers = of_read_number(ireg + 1, 1);
 276         }
 277
 278         ireg = of_get_property(np, "reg", &ilen);
 279         if (!ireg) {
 280                 pr_err("icp_native: Can't find interrupt reg property");
 281                 return -1;
 282         }
 283
 284         reg_tuple_size = (of_n_addr_cells(np) + of_n_size_cells(np)) * 4;
 285         if (((ilen % reg_tuple_size) != 0)
 286             || (num_servers && (num_servers != (ilen / reg_tuple_size)))) {
 287                 pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
 288                        ilen / reg_tuple_size, num_servers);
 289                 return -1;
 290         }
 291
 292         for (i = 0; i < (ilen / reg_tuple_size); i++) {
 293                 struct resource r;
 294                 int err;
 295
 296                 err = of_address_to_resource(np, i, &r);
 297                 if (err) {
 298                         pr_err("icp_native: Could not translate ICP MMIO"
 299                                " for interrupt server 0x%x (%d)\n", *indx, err);
 300                         return -1;
 301                 }
 302
 303                 if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
 304                         return -1;
 305
 306                 (*indx)++;
 307         }
 308         return 0;
 309 }
 310
 311 static const struct icp_ops icp_native_ops = {
 312         .get_irq        = icp_native_get_irq,
 313         .eoi            = icp_native_eoi,
 314         .set_priority   = icp_native_set_cpu_priority,
 315         .teardown_cpu   = icp_native_teardown_cpu,
 316         .flush_ipi      = icp_native_flush_ipi,
 317 #ifdef CONFIG_SMP
 318         .ipi_action     = icp_native_ipi_action,
 319         .cause_ipi      = icp_native_cause_ipi,
 320 #endif
 321 };
 322
 323 int __init icp_native_init(void)
 324 {
 325         struct device_node *np;
 326         u32 indx = 0;
 327         int found = 0;
 328
 329         for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
 330                 if (icp_native_init_one_node(np, &indx) == 0)
 331                         found = 1;
 332         if (!found) {
 333                 for_each_node_by_type(np,
 334                         "PowerPC-External-Interrupt-Presentation") {
 335                                 if (icp_native_init_one_node(np, &indx) == 0)
 336                                         found = 1;
 337                 }
 338         }
 339
 340         if (found == 0)
 341                 return -ENODEV;
 342
 343         icp_ops = &icp_native_ops;
 344
 345         return 0;
 346 }