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