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