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