arch/metag/kernel/irq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Linux/Meta general interrupt handling code
   4  *
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/interrupt.h>
   9 #include <linux/init.h>
  10 #include <linux/irqchip/metag-ext.h>
  11 #include <linux/irqchip/metag.h>
  12 #include <linux/irqdomain.h>
  13 #include <linux/ratelimit.h>
  14
  15 #include <asm/core_reg.h>
  16 #include <asm/mach/arch.h>
  17 #include <linux/uaccess.h>
  18
  19 #ifdef CONFIG_4KSTACKS
  20 union irq_ctx {
  21         struct thread_info      tinfo;
  22         u32                     stack[THREAD_SIZE/sizeof(u32)];
  23 };
  24
  25 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  26 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  27 #endif
  28
  29 static struct irq_domain *root_domain;
  30
  31 static unsigned int startup_meta_irq(struct irq_data *data)
  32 {
  33         tbi_startup_interrupt(data->hwirq);
  34         return 0;
  35 }
  36
  37 static void shutdown_meta_irq(struct irq_data *data)
  38 {
  39         tbi_shutdown_interrupt(data->hwirq);
  40 }
  41
  42 void do_IRQ(int irq, struct pt_regs *regs)
  43 {
  44         struct pt_regs *old_regs = set_irq_regs(regs);
  45 #ifdef CONFIG_4KSTACKS
  46         struct irq_desc *desc;
  47         union irq_ctx *curctx, *irqctx;
  48         u32 *isp;
  49 #endif
  50
  51         irq_enter();
  52
  53         irq = irq_linear_revmap(root_domain, irq);
  54
  55 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  56         /* Debugging check for stack overflow: is there less than 1KB free? */
  57         {
  58                 unsigned long sp;
  59
  60                 sp = __core_reg_get(A0StP);
  61                 sp &= THREAD_SIZE - 1;
  62
  63                 if (unlikely(sp > (THREAD_SIZE - 1024)))
  64                         pr_err("Stack overflow in do_IRQ: %ld\n", sp);
  65         }
  66 #endif
  67
  68
  69 #ifdef CONFIG_4KSTACKS
  70         curctx = (union irq_ctx *) current_thread_info();
  71         irqctx = hardirq_ctx[smp_processor_id()];
  72
  73         /*
  74          * this is where we switch to the IRQ stack. However, if we are
  75          * already using the IRQ stack (because we interrupted a hardirq
  76          * handler) we can't do that and just have to keep using the
  77          * current stack (which is the irq stack already after all)
  78          */
  79         if (curctx != irqctx) {
  80                 /* build the stack frame on the IRQ stack */
  81                 isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
  82                 irqctx->tinfo.task = curctx->tinfo.task;
  83
  84                 /*
  85                  * Copy the softirq bits in preempt_count so that the
  86                  * softirq checks work in the hardirq context.
  87                  */
  88                 irqctx->tinfo.preempt_count =
  89                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
  90                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
  91
  92                 desc = irq_to_desc(irq);
  93
  94                 asm volatile (
  95                         "MOV   D0.5,%0\n"
  96                         "MOV   D1Ar1,%1\n"
  97                         "MOV   D1RtP,%2\n"
  98                         "SWAP  A0StP,D0.5\n"
  99                         "SWAP  PC,D1RtP\n"
 100                         "MOV   A0StP,D0.5\n"
 101                         :
 102                         : "r" (isp), "r" (desc), "r" (desc->handle_irq)
 103                         : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 104                           "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 105                           "D0.5"
 106                         );
 107         } else
 108 #endif
 109                 generic_handle_irq(irq);
 110
 111         irq_exit();
 112
 113         set_irq_regs(old_regs);
 114 }
 115
 116 #ifdef CONFIG_4KSTACKS
 117
 118 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 119
 120 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 121
 122 /*
 123  * allocate per-cpu stacks for hardirq and for softirq processing
 124  */
 125 void irq_ctx_init(int cpu)
 126 {
 127         union irq_ctx *irqctx;
 128
 129         if (hardirq_ctx[cpu])
 130                 return;
 131
 132         irqctx = (union irq_ctx *) &hardirq_stack[cpu * THREAD_SIZE];
 133         irqctx->tinfo.task              = 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.cpu               = cpu;
 143         irqctx->tinfo.preempt_count     = 0;
 144         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 145
 146         softirq_ctx[cpu] = irqctx;
 147
 148         pr_info("CPU %u irqstacks, hard=%p soft=%p\n",
 149                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 150 }
 151
 152 void irq_ctx_exit(int cpu)
 153 {
 154         hardirq_ctx[smp_processor_id()] = NULL;
 155 }
 156
 157 extern asmlinkage void __do_softirq(void);
 158
 159 void do_softirq_own_stack(void)
 160 {
 161         struct thread_info *curctx;
 162         union irq_ctx *irqctx;
 163         u32 *isp;
 164
 165         curctx = current_thread_info();
 166         irqctx = softirq_ctx[smp_processor_id()];
 167         irqctx->tinfo.task = curctx->task;
 168
 169         /* build the stack frame on the softirq stack */
 170         isp = (u32 *) ((char *)irqctx + sizeof(struct thread_info));
 171
 172         asm volatile (
 173                 "MOV   D0.5,%0\n"
 174                 "SWAP  A0StP,D0.5\n"
 175                 "CALLR D1RtP,___do_softirq\n"
 176                 "MOV   A0StP,D0.5\n"
 177                 :
 178                 : "r" (isp)
 179                 : "memory", "cc", "D1Ar1", "D0Ar2", "D1Ar3", "D0Ar4",
 180                   "D1Ar5", "D0Ar6", "D0Re0", "D1Re0", "D0.4", "D1RtP",
 181                   "D0.5"
 182                 );
 183 }
 184 #endif
 185
 186 static struct irq_chip meta_irq_type = {
 187         .name = "META-IRQ",
 188         .irq_startup = startup_meta_irq,
 189         .irq_shutdown = shutdown_meta_irq,
 190 };
 191
 192 /**
 193  * tbisig_map() - Map a TBI signal number to a virtual IRQ number.
 194  * @hw:         Number of the TBI signal. Must be in range.
 195  *
 196  * Returns:     The virtual IRQ number of the TBI signal number IRQ specified by
 197  *              @hw.
 198  */
 199 int tbisig_map(unsigned int hw)
 200 {
 201         return irq_create_mapping(root_domain, hw);
 202 }
 203
 204 /**
 205  * metag_tbisig_map() - map a tbi signal to a Linux virtual IRQ number
 206  * @d:          root irq domain
 207  * @irq:        virtual irq number
 208  * @hw:         hardware irq number (TBI signal number)
 209  *
 210  * This sets up a virtual irq for a specified TBI signal number.
 211  */
 212 static int metag_tbisig_map(struct irq_domain *d, unsigned int irq,
 213                             irq_hw_number_t hw)
 214 {
 215 #ifdef CONFIG_SMP
 216         irq_set_chip_and_handler(irq, &meta_irq_type, handle_percpu_irq);
 217 #else
 218         irq_set_chip_and_handler(irq, &meta_irq_type, handle_simple_irq);
 219 #endif
 220         return 0;
 221 }
 222
 223 static const struct irq_domain_ops metag_tbisig_domain_ops = {
 224         .map = metag_tbisig_map,
 225 };
 226
 227 /*
 228  * void init_IRQ(void)
 229  *
 230  * Parameters:  None
 231  *
 232  * Returns:     Nothing
 233  *
 234  * This function should be called during kernel startup to initialize
 235  * the IRQ handling routines.
 236  */
 237 void __init init_IRQ(void)
 238 {
 239         root_domain = irq_domain_add_linear(NULL, 32,
 240                                             &metag_tbisig_domain_ops, NULL);
 241         if (unlikely(!root_domain))
 242                 panic("init_IRQ: cannot add root IRQ domain");
 243
 244         irq_ctx_init(smp_processor_id());
 245
 246         init_internal_IRQ();
 247         init_external_IRQ();
 248
 249         if (machine_desc->init_irq)
 250                 machine_desc->init_irq();
 251 }
 252
 253 int __init arch_probe_nr_irqs(void)
 254 {
 255         if (machine_desc->nr_irqs)
 256                 nr_irqs = machine_desc->nr_irqs;
 257         return 0;
 258 }
 259
 260 #ifdef CONFIG_HOTPLUG_CPU
 261 /*
 262  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 263  * the affinity settings do not allow other CPUs, force them onto any
 264  * available CPU.
 265  */
 266 void migrate_irqs(void)
 267 {
 268         unsigned int i, cpu = smp_processor_id();
 269
 270         for_each_active_irq(i) {
 271                 struct irq_data *data = irq_get_irq_data(i);
 272                 struct cpumask *mask;
 273                 unsigned int newcpu;
 274
 275                 if (irqd_is_per_cpu(data))
 276                         continue;
 277
 278                 mask = irq_data_get_affinity_mask(data);
 279                 if (!cpumask_test_cpu(cpu, mask))
 280                         continue;
 281
 282                 newcpu = cpumask_any_and(mask, cpu_online_mask);
 283
 284                 if (newcpu >= nr_cpu_ids) {
 285                         pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
 286                                             i, cpu);
 287
 288                         cpumask_setall(mask);
 289                 }
 290                 irq_set_affinity(i, mask);
 291         }
 292 }
 293 #endif /* CONFIG_HOTPLUG_CPU */