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 0;
 128
 129         irq = irq_find_mapping(xics_host, vec);
 130         if (likely(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 0;
 142 }
 143
 144 #ifdef CONFIG_SMP
 145
 146 static void icp_native_cause_ipi(int cpu)
 147 {
 148         kvmppc_set_host_ipi(cpu, 1);
 149         icp_native_set_qirr(cpu, IPI_PRIORITY);
 150 }
 151
 152 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 153 void icp_native_cause_ipi_rm(int cpu)
 154 {
 155         /*
 156          * Currently not used to send IPIs to another CPU
 157          * on the same core. Only caller is KVM real mode.
 158          * Need the physical address of the XICS to be
 159          * previously saved in kvm_hstate in the paca.
 160          */
 161         void __iomem *xics_phys;
 162
 163         /*
 164          * Just like the cause_ipi functions, it is required to
 165          * include a full barrier before causing the IPI.
 166          */
 167         xics_phys = paca[cpu].kvm_hstate.xics_phys;
 168         mb();
 169         __raw_rm_writeb(IPI_PRIORITY, xics_phys + XICS_MFRR);
 170 }
 171 #endif
 172
 173 /*
 174  * Called when an interrupt is received on an off-line CPU to
 175  * clear the interrupt, so that the CPU can go back to nap mode.
 176  */
 177 void icp_native_flush_interrupt(void)
 178 {
 179         unsigned int xirr = icp_native_get_xirr();
 180         unsigned int vec = xirr & 0x00ffffff;
 181
 182         if (vec == XICS_IRQ_SPURIOUS)
 183                 return;
 184         if (vec == XICS_IPI) {
 185                 /* Clear pending IPI */
 186                 int cpu = smp_processor_id();
 187                 kvmppc_set_host_ipi(cpu, 0);
 188                 icp_native_set_qirr(cpu, 0xff);
 189         } else {
 190                 pr_err("XICS: hw interrupt 0x%x to offline cpu, disabling\n",
 191                        vec);
 192                 xics_mask_unknown_vec(vec);
 193         }
 194         /* EOI the interrupt */
 195         icp_native_set_xirr(xirr);
 196 }
 197
 198 void xics_wake_cpu(int cpu)
 199 {
 200         icp_native_set_qirr(cpu, IPI_PRIORITY);
 201 }
 202 EXPORT_SYMBOL_GPL(xics_wake_cpu);
 203
 204 static irqreturn_t icp_native_ipi_action(int irq, void *dev_id)
 205 {
 206         int cpu = smp_processor_id();
 207
 208         kvmppc_set_host_ipi(cpu, 0);
 209         icp_native_set_qirr(cpu, 0xff);
 210
 211         return smp_ipi_demux();
 212 }
 213
 214 #endif /* CONFIG_SMP */
 215
 216 static int __init icp_native_map_one_cpu(int hw_id, unsigned long addr,
 217                                          unsigned long size)
 218 {
 219         char *rname;
 220         int i, cpu = -1;
 221
 222         /* This may look gross but it's good enough for now, we don't quite
 223          * have a hard -> linux processor id matching.
 224          */
 225         for_each_possible_cpu(i) {
 226                 if (!cpu_present(i))
 227                         continue;
 228                 if (hw_id == get_hard_smp_processor_id(i)) {
 229                         cpu = i;
 230                         break;
 231                 }
 232         }
 233
 234         /* Fail, skip that CPU. Don't print, it's normal, some XICS come up
 235          * with way more entries in there than you have CPUs
 236          */
 237         if (cpu == -1)
 238                 return 0;
 239
 240         rname = kasprintf(GFP_KERNEL, "CPU %d [0x%x] Interrupt Presentation",
 241                           cpu, hw_id);
 242
 243         if (!request_mem_region(addr, size, rname)) {
 244                 pr_warning("icp_native: Could not reserve ICP MMIO"
 245                            " for CPU %d, interrupt server #0x%x\n",
 246                            cpu, hw_id);
 247                 return -EBUSY;
 248         }
 249
 250         icp_native_regs[cpu] = ioremap(addr, size);
 251         kvmppc_set_xics_phys(cpu, addr);
 252         if (!icp_native_regs[cpu]) {
 253                 pr_warning("icp_native: Failed ioremap for CPU %d, "
 254                            "interrupt server #0x%x, addr %#lx\n",
 255                            cpu, hw_id, addr);
 256                 release_mem_region(addr, size);
 257                 return -ENOMEM;
 258         }
 259         return 0;
 260 }
 261
 262 static int __init icp_native_init_one_node(struct device_node *np,
 263                                            unsigned int *indx)
 264 {
 265         unsigned int ilen;
 266         const __be32 *ireg;
 267         int i;
 268         int reg_tuple_size;
 269         int num_servers = 0;
 270
 271         /* This code does the theorically broken assumption that the interrupt
 272          * server numbers are the same as the hard CPU numbers.
 273          * This happens to be the case so far but we are playing with fire...
 274          * should be fixed one of these days. -BenH.
 275          */
 276         ireg = of_get_property(np, "ibm,interrupt-server-ranges", &ilen);
 277
 278         /* Do that ever happen ? we'll know soon enough... but even good'old
 279          * f80 does have that property ..
 280          */
 281         WARN_ON((ireg == NULL) || (ilen != 2*sizeof(u32)));
 282
 283         if (ireg) {
 284                 *indx = of_read_number(ireg, 1);
 285                 if (ilen >= 2*sizeof(u32))
 286                         num_servers = of_read_number(ireg + 1, 1);
 287         }
 288
 289         ireg = of_get_property(np, "reg", &ilen);
 290         if (!ireg) {
 291                 pr_err("icp_native: Can't find interrupt reg property");
 292                 return -1;
 293         }
 294
 295         reg_tuple_size = (of_n_addr_cells(np) + of_n_size_cells(np)) * 4;
 296         if (((ilen % reg_tuple_size) != 0)
 297             || (num_servers && (num_servers != (ilen / reg_tuple_size)))) {
 298                 pr_err("icp_native: ICP reg len (%d) != num servers (%d)",
 299                        ilen / reg_tuple_size, num_servers);
 300                 return -1;
 301         }
 302
 303         for (i = 0; i < (ilen / reg_tuple_size); i++) {
 304                 struct resource r;
 305                 int err;
 306
 307                 err = of_address_to_resource(np, i, &r);
 308                 if (err) {
 309                         pr_err("icp_native: Could not translate ICP MMIO"
 310                                " for interrupt server 0x%x (%d)\n", *indx, err);
 311                         return -1;
 312                 }
 313
 314                 if (icp_native_map_one_cpu(*indx, r.start, resource_size(&r)))
 315                         return -1;
 316
 317                 (*indx)++;
 318         }
 319         return 0;
 320 }
 321
 322 static const struct icp_ops icp_native_ops = {
 323         .get_irq        = icp_native_get_irq,
 324         .eoi            = icp_native_eoi,
 325         .set_priority   = icp_native_set_cpu_priority,
 326         .teardown_cpu   = icp_native_teardown_cpu,
 327         .flush_ipi      = icp_native_flush_ipi,
 328 #ifdef CONFIG_SMP
 329         .ipi_action     = icp_native_ipi_action,
 330         .cause_ipi      = icp_native_cause_ipi,
 331 #endif
 332 };
 333
 334 int __init icp_native_init(void)
 335 {
 336         struct device_node *np;
 337         u32 indx = 0;
 338         int found = 0;
 339
 340         for_each_compatible_node(np, NULL, "ibm,ppc-xicp")
 341                 if (icp_native_init_one_node(np, &indx) == 0)
 342                         found = 1;
 343         if (!found) {
 344                 for_each_node_by_type(np,
 345                         "PowerPC-External-Interrupt-Presentation") {
 346                                 if (icp_native_init_one_node(np, &indx) == 0)
 347                                         found = 1;
 348                 }
 349         }
 350
 351         if (found == 0)
 352                 return -ENODEV;
 353
 354         icp_ops = &icp_native_ops;
 355
 356         return 0;
 357 }