arch/powerpc/sysdev/xics/icp-opal.c

   1 /*
   2  * Copyright 2016 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 #include <linux/types.h>
  10 #include <linux/kernel.h>
  11 #include <linux/irq.h>
  12 #include <linux/smp.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/cpu.h>
  15 #include <linux/of.h>
  16
  17 #include <asm/smp.h>
  18 #include <asm/irq.h>
  19 #include <asm/errno.h>
  20 #include <asm/xics.h>
  21 #include <asm/io.h>
  22 #include <asm/opal.h>
  23
  24 static void icp_opal_teardown_cpu(void)
  25 {
  26         int hw_cpu = hard_smp_processor_id();
  27
  28         /* Clear any pending IPI */
  29         opal_int_set_mfrr(hw_cpu, 0xff);
  30 }
  31
  32 static void icp_opal_flush_ipi(void)
  33 {
  34         /*
  35          * We take the ipi irq but and never return so we need to EOI the IPI,
  36          * but want to leave our priority 0.
  37          *
  38          * Should we check all the other interrupts too?
  39          * Should we be flagging idle loop instead?
  40          * Or creating some task to be scheduled?
  41          */
  42         opal_int_eoi((0x00 << 24) | XICS_IPI);
  43 }
  44
  45 static unsigned int icp_opal_get_irq(void)
  46 {
  47         unsigned int xirr;
  48         unsigned int vec;
  49         unsigned int irq;
  50         int64_t rc;
  51
  52         rc = opal_int_get_xirr(&xirr, false);
  53         if (rc < 0)
  54                 return NO_IRQ;
  55         xirr = be32_to_cpu(xirr);
  56         vec = xirr & 0x00ffffff;
  57         if (vec == XICS_IRQ_SPURIOUS)
  58                 return NO_IRQ;
  59
  60         irq = irq_find_mapping(xics_host, vec);
  61         if (likely(irq != NO_IRQ)) {
  62                 xics_push_cppr(vec);
  63                 return irq;
  64         }
  65
  66         /* We don't have a linux mapping, so have rtas mask it. */
  67         xics_mask_unknown_vec(vec);
  68
  69         /* We might learn about it later, so EOI it */
  70         opal_int_eoi(xirr);
  71
  72         return NO_IRQ;
  73 }
  74
  75 static void icp_opal_set_cpu_priority(unsigned char cppr)
  76 {
  77         xics_set_base_cppr(cppr);
  78         opal_int_set_cppr(cppr);
  79         iosync();
  80 }
  81
  82 static void icp_opal_eoi(struct irq_data *d)
  83 {
  84         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  85         int64_t rc;
  86
  87         iosync();
  88         rc = opal_int_eoi((xics_pop_cppr() << 24) | hw_irq);
  89
  90         /*
  91          * EOI tells us whether there are more interrupts to fetch.
  92          *
  93          * Some HW implementations might not be able to send us another
  94          * external interrupt in that case, so we force a replay.
  95          */
  96         if (rc > 0)
  97                 force_external_irq_replay();
  98 }
  99
 100 #ifdef CONFIG_SMP
 101
 102 static void icp_opal_cause_ipi(int cpu, unsigned long data)
 103 {
 104         int hw_cpu = get_hard_smp_processor_id(cpu);
 105
 106         opal_int_set_mfrr(hw_cpu, IPI_PRIORITY);
 107 }
 108
 109 static irqreturn_t icp_opal_ipi_action(int irq, void *dev_id)
 110 {
 111         int hw_cpu = hard_smp_processor_id();
 112
 113         opal_int_set_mfrr(hw_cpu, 0xff);
 114
 115         return smp_ipi_demux();
 116 }
 117
 118 #endif /* CONFIG_SMP */
 119
 120 static const struct icp_ops icp_opal_ops = {
 121         .get_irq        = icp_opal_get_irq,
 122         .eoi            = icp_opal_eoi,
 123         .set_priority   = icp_opal_set_cpu_priority,
 124         .teardown_cpu   = icp_opal_teardown_cpu,
 125         .flush_ipi      = icp_opal_flush_ipi,
 126 #ifdef CONFIG_SMP
 127         .ipi_action     = icp_opal_ipi_action,
 128         .cause_ipi      = icp_opal_cause_ipi,
 129 #endif
 130 };
 131
 132 int icp_opal_init(void)
 133 {
 134         struct device_node *np;
 135
 136         np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc");
 137         if (!np)
 138                 return -ENODEV;
 139
 140         icp_ops = &icp_opal_ops;
 141
 142         printk("XICS: Using OPAL ICP fallbacks\n");
 143
 144         return 0;
 145 }
 146