arch/powerpc/sysdev/xics/icp-hv.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 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/irq.h>
  13 #include <linux/smp.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/init.h>
  16 #include <linux/cpu.h>
  17 #include <linux/of.h>
  18
  19 #include <asm/smp.h>
  20 #include <asm/irq.h>
  21 #include <asm/errno.h>
  22 #include <asm/xics.h>
  23 #include <asm/io.h>
  24 #include <asm/hvcall.h>
  25
  26 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
  27 {
  28         unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
  29         long rc;
  30         unsigned int ret = XICS_IRQ_SPURIOUS;
  31
  32         rc = plpar_hcall(H_XIRR, retbuf, cppr);
  33         if (rc == H_SUCCESS) {
  34                 ret = (unsigned int)retbuf[0];
  35         } else {
  36                 pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
  37                         __func__, cppr, rc);
  38                 WARN_ON_ONCE(1);
  39         }
  40
  41         return ret;
  42 }
  43
  44 static inline void icp_hv_set_cppr(u8 value)
  45 {
  46         long rc = plpar_hcall_norets(H_CPPR, value);
  47         if (rc != H_SUCCESS) {
  48                 pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
  49                         __func__, value, rc);
  50                 WARN_ON_ONCE(1);
  51         }
  52 }
  53
  54 static inline void icp_hv_set_xirr(unsigned int value)
  55 {
  56         long rc = plpar_hcall_norets(H_EOI, value);
  57         if (rc != H_SUCCESS) {
  58                 pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
  59                         __func__, value, rc);
  60                 WARN_ON_ONCE(1);
  61                 icp_hv_set_cppr(value >> 24);
  62         }
  63 }
  64
  65 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
  66 {
  67         int hw_cpu = get_hard_smp_processor_id(n_cpu);
  68         long rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
  69         if (rc != H_SUCCESS) {
  70                 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
  71                         "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
  72                 WARN_ON_ONCE(1);
  73         }
  74 }
  75
  76 static void icp_hv_eoi(struct irq_data *d)
  77 {
  78         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  79
  80         iosync();
  81         icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
  82 }
  83
  84 static void icp_hv_teardown_cpu(void)
  85 {
  86         int cpu = smp_processor_id();
  87
  88         /* Clear any pending IPI */
  89         icp_hv_set_qirr(cpu, 0xff);
  90 }
  91
  92 static void icp_hv_flush_ipi(void)
  93 {
  94         /* We take the ipi irq but and never return so we
  95          * need to EOI the IPI, but want to leave our priority 0
  96          *
  97          * should we check all the other interrupts too?
  98          * should we be flagging idle loop instead?
  99          * or creating some task to be scheduled?
 100          */
 101
 102         icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
 103 }
 104
 105 static unsigned int icp_hv_get_irq(void)
 106 {
 107         unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
 108         unsigned int vec = xirr & 0x00ffffff;
 109         unsigned int irq;
 110
 111         if (vec == XICS_IRQ_SPURIOUS)
 112                 return NO_IRQ;
 113
 114         irq = irq_find_mapping(xics_host, vec);
 115         if (likely(irq != NO_IRQ)) {
 116                 xics_push_cppr(vec);
 117                 return irq;
 118         }
 119
 120         /* We don't have a linux mapping, so have rtas mask it. */
 121         xics_mask_unknown_vec(vec);
 122
 123         /* We might learn about it later, so EOI it */
 124         icp_hv_set_xirr(xirr);
 125
 126         return NO_IRQ;
 127 }
 128
 129 static void icp_hv_set_cpu_priority(unsigned char cppr)
 130 {
 131         xics_set_base_cppr(cppr);
 132         icp_hv_set_cppr(cppr);
 133         iosync();
 134 }
 135
 136 #ifdef CONFIG_SMP
 137
 138 static void icp_hv_cause_ipi(int cpu, unsigned long data)
 139 {
 140         icp_hv_set_qirr(cpu, IPI_PRIORITY);
 141 }
 142
 143 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
 144 {
 145         int cpu = smp_processor_id();
 146
 147         icp_hv_set_qirr(cpu, 0xff);
 148
 149         return smp_ipi_demux();
 150 }
 151
 152 #endif /* CONFIG_SMP */
 153
 154 static const struct icp_ops icp_hv_ops = {
 155         .get_irq        = icp_hv_get_irq,
 156         .eoi            = icp_hv_eoi,
 157         .set_priority   = icp_hv_set_cpu_priority,
 158         .teardown_cpu   = icp_hv_teardown_cpu,
 159         .flush_ipi      = icp_hv_flush_ipi,
 160 #ifdef CONFIG_SMP
 161         .ipi_action     = icp_hv_ipi_action,
 162         .cause_ipi      = icp_hv_cause_ipi,
 163 #endif
 164 };
 165
 166 int icp_hv_init(void)
 167 {
 168         struct device_node *np;
 169
 170         np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
 171         if (!np)
 172                 np = of_find_node_by_type(NULL,
 173                                     "PowerPC-External-Interrupt-Presentation");
 174         if (!np)
 175                 return -ENODEV;
 176
 177         icp_ops = &icp_hv_ops;
 178
 179         return 0;
 180 }
 181