arch/metag/kernel/irq.c

   1 /*
   2  * Linux/Meta general interrupt handling code
   3  *
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/init.h>
   9 #include <linux/irqdomain.h>
  10 #include <linux/ratelimit.h>
  11
  12 #include <asm/core_reg.h>
  13 #include <asm/mach/arch.h>
  14 #include <asm/uaccess.h>
  15
  16 #ifdef CONFIG_4KSTACKS
  17 union irq_ctx {
  18         struct thread_info      tinfo;
  19         u32                     stack[THREAD_SIZE/sizeof(u32)];
  20 };
  21
  22 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  23 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  24 #endif
  25
  26 struct irq_domain *root_domain;
  27
  28 static unsigned int startup_meta_irq(struct irq_data *data)
  29 {
  30         tbi_startup_interrupt(data->hwirq);
  31         return 0;
  32 }
  33
  34 static void shutdown_meta_irq(struct irq_data *data)
  35 {
  36         tbi_shutdown_interrupt(data->hwirq);
  37 }
  38
  39 void do_IRQ(int irq, struct pt_regs *regs)
  40 {
  41         struct pt_regs *old_regs = set_irq_regs(regs);
  42 #ifdef CONFIG_4KSTACKS
  43         struct irq_desc *desc;
  44         union irq_ctx *curctx, *irqctx;
  45         u32 *isp;
  46 #endif
  47
  48         irq_enter();
  49
  50         irq = irq_linear_revmap(root_domain, irq);
  51
  52 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  53         /* Debugging check for stack overflow: is there less than 1KB free? */
  54         {
  55                 unsigned long sp;
  56
  57                 sp = __core_reg_get(A0StP);
  58                 sp &= THREAD_SIZE - 1;
  59
  60                 if (unlikely(sp > (THREAD_SIZE - 1024)))
  61                         pr_err("Stack overflow in do_IRQ: %ld\n", sp);
  62         }
  63 #endif
  64
  65
  66 #ifdef CONFIG_4KSTACKS
  67         curctx = (union irq_ctx *) current_thread_info();
  68         irqctx = hardirq_ctx[smp_processor_id()];
  69
  70         /*
  71          * this is where we switch to the IRQ stack. However, if we are
  72          * already using the IRQ stack (because we interrupted a hardirq
  73          * handler) we can't do that and just have to keep using the
  74          * current stack (which is the irq stack already after all)
  75          */
  76         if (curctx != irqctx) {
  77                 /* build the stack frame on the IRQ stack */
  78                 isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
  79                 irqctx->tinfo.task = curctx->tinfo.task;
  80
  81                 /*
  82                  * Copy the softirq bits in preempt_count so that the
  83                  * softirq checks work in the hardirq context.
  84                  */
  85                 irqctx->tinfo.preempt_count =
  86                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
  87                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
  88
  89                 desc = irq_to_desc(irq);
  90
  91                 asm volatile (
  92                         "MOV   D0.5,%0\n"
  93                         "MOV   D1Ar1,%1\n"
  94                         "MOV   D1RtP,%2\n"
  95                         "MOV   D0Ar2,%3\n"
  96                         "SWAP  A0StP,D0.5\n"
  97                         "SWAP  PC,D1RtP\n"
  98                         "MOV   A0StP,D0.5\n"
  99                         :
 100                         : "r" (isp), "r" (irq), "r" (desc->handle_irq),
 101                           "r" (desc)
 102                         : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 103                           "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 104                           "D0.5"
 105                         );
 106         } else
 107 #endif
 108                 generic_handle_irq(irq);
 109
 110         irq_exit();
 111
 112         set_irq_regs(old_regs);
 113 }
 114
 115 #ifdef CONFIG_4KSTACKS
 116
 117 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 118
 119 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 120
 121 /*
 122  * allocate per-cpu stacks for hardirq and for softirq processing
 123  */
 124 void irq_ctx_init(int cpu)
 125 {
 126         union irq_ctx *irqctx;
 127
 128         if (hardirq_ctx[cpu])
 129                 return;
 130
 131         irqctx = (union irq_ctx *) &hardirq_stack[cpu * THREAD_SIZE];
 132         irqctx->tinfo.task              = NULL;
 133         irqctx->tinfo.exec_domain       = NULL;
 134         irqctx->tinfo.cpu               = cpu;
 135         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 136         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 137
 138         hardirq_ctx[cpu] = irqctx;
 139
 140         irqctx = (union irq_ctx *) &softirq_stack[cpu * THREAD_SIZE];
 141         irqctx->tinfo.task              = NULL;
 142         irqctx->tinfo.exec_domain       = NULL;
 143         irqctx->tinfo.cpu               = cpu;
 144         irqctx->tinfo.preempt_count     = 0;
 145         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 146
 147         softirq_ctx[cpu] = irqctx;
 148
 149         pr_info("CPU %u irqstacks, hard=%p soft=%p\n",
 150                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 151 }
 152
 153 void irq_ctx_exit(int cpu)
 154 {
 155         hardirq_ctx[smp_processor_id()] = NULL;
 156 }
 157
 158 extern asmlinkage void __do_softirq(void);
 159
 160 asmlinkage void do_softirq(void)
 161 {
 162         unsigned long flags;
 163         struct thread_info *curctx;
 164         union irq_ctx *irqctx;
 165         u32 *isp;
 166
 167         if (in_interrupt())
 168                 return;
 169
 170         local_irq_save(flags);
 171
 172         if (local_softirq_pending()) {
 173                 curctx = current_thread_info();
 174                 irqctx = softirq_ctx[smp_processor_id()];
 175                 irqctx->tinfo.task = curctx->task;
 176
 177                 /* build the stack frame on the softirq stack */
 178                 isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
 179
 180                 asm volatile (
 181                         "MOV   D0.5,%0\n"
 182                         "SWAP  A0StP,D0.5\n"
 183                         "CALLR D1RtP,___do_softirq\n"
 184                         "MOV   A0StP,D0.5\n"
 185                         :
 186                         : "r" (isp)
 187                         : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 188                           "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 189                           "D0.5"
 190                         );
 191                 /*
 192                  * Shouldn't happen, we returned above if in_interrupt():
 193                  */
 194                 WARN_ON_ONCE(softirq_count());
 195         }
 196
 197         local_irq_restore(flags);
 198 }
 199 #endif
 200
 201 static struct irq_chip meta_irq_type = {
 202         .name = "META-IRQ",
 203         .irq_startup = startup_meta_irq,
 204         .irq_shutdown = shutdown_meta_irq,
 205 };
 206
 207 /**
 208  * tbisig_map() - Map a TBI signal number to a virtual IRQ number.
 209  * @hw:         Number of the TBI signal. Must be in range.
 210  *
 211  * Returns:     The virtual IRQ number of the TBI signal number IRQ specified by
 212  *              @hw.
 213  */
 214 int tbisig_map(unsigned int hw)
 215 {
 216         return irq_create_mapping(root_domain, hw);
 217 }
 218
 219 /**
 220  * metag_tbisig_map() - map a tbi signal to a Linux virtual IRQ number
 221  * @d:          root irq domain
 222  * @irq:        virtual irq number
 223  * @hw:         hardware irq number (TBI signal number)
 224  *
 225  * This sets up a virtual irq for a specified TBI signal number.
 226  */
 227 static int metag_tbisig_map(struct irq_domain *d, unsigned int irq,
 228                             irq_hw_number_t hw)
 229 {
 230 #ifdef CONFIG_SMP
 231         irq_set_chip_and_handler(irq, &meta_irq_type, handle_percpu_irq);
 232 #else
 233         irq_set_chip_and_handler(irq, &meta_irq_type, handle_simple_irq);
 234 #endif
 235         return 0;
 236 }
 237
 238 static const struct irq_domain_ops metag_tbisig_domain_ops = {
 239         .map = metag_tbisig_map,
 240 };
 241
 242 /*
 243  * void init_IRQ(void)
 244  *
 245  * Parameters:  None
 246  *
 247  * Returns:     Nothing
 248  *
 249  * This function should be called during kernel startup to initialize
 250  * the IRQ handling routines.
 251  */
 252 void __init init_IRQ(void)
 253 {
 254         root_domain = irq_domain_add_linear(NULL, 32,
 255                                             &metag_tbisig_domain_ops, NULL);
 256         if (unlikely(!root_domain))
 257                 panic("init_IRQ: cannot add root IRQ domain");
 258
 259         irq_ctx_init(smp_processor_id());
 260
 261         if (machine_desc->init_irq)
 262                 machine_desc->init_irq();
 263 }
 264
 265 int __init arch_probe_nr_irqs(void)
 266 {
 267         if (machine_desc->nr_irqs)
 268                 nr_irqs = machine_desc->nr_irqs;
 269         return 0;
 270 }
 271
 272 #ifdef CONFIG_HOTPLUG_CPU
 273 static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu)
 274 {
 275         struct irq_desc *desc = irq_to_desc(irq);
 276         struct irq_chip *chip = irq_data_get_irq_chip(data);
 277
 278         raw_spin_lock_irq(&desc->lock);
 279         if (chip->irq_set_affinity)
 280                 chip->irq_set_affinity(data, cpumask_of(cpu), false);
 281         raw_spin_unlock_irq(&desc->lock);
 282 }
 283
 284 /*
 285  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 286  * the affinity settings do not allow other CPUs, force them onto any
 287  * available CPU.
 288  */
 289 void migrate_irqs(void)
 290 {
 291         unsigned int i, cpu = smp_processor_id();
 292         struct irq_desc *desc;
 293
 294         for_each_irq_desc(i, desc) {
 295                 struct irq_data *data = irq_desc_get_irq_data(desc);
 296                 unsigned int newcpu;
 297
 298                 if (irqd_is_per_cpu(data))
 299                         continue;
 300
 301                 if (!cpumask_test_cpu(cpu, data->affinity))
 302                         continue;
 303
 304                 newcpu = cpumask_any_and(data->affinity, cpu_online_mask);
 305
 306                 if (newcpu >= nr_cpu_ids) {
 307                         pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
 308                                             i, cpu);
 309
 310                         cpumask_setall(data->affinity);
 311                         newcpu = cpumask_any_and(data->affinity,
 312                                                  cpu_online_mask);
 313                 }
 314
 315                 route_irq(data, i, newcpu);
 316         }
 317 }
 318 #endif /* CONFIG_HOTPLUG_CPU */