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/cpu.h>
  16 #include <linux/of.h>
  17
  18 #include <asm/smp.h>
  19 #include <asm/irq.h>
  20 #include <asm/errno.h>
  21 #include <asm/xics.h>
  22 #include <asm/io.h>
  23 #include <asm/hvcall.h>
  24
  25 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
  26 {
  27         unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
  28         long rc;
  29         unsigned int ret = XICS_IRQ_SPURIOUS;
  30
  31         rc = plpar_hcall(H_XIRR, retbuf, cppr);
  32         if (rc == H_SUCCESS) {
  33                 ret = (unsigned int)retbuf[0];
  34         } else {
  35                 pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
  36                         __func__, cppr, rc);
  37                 WARN_ON_ONCE(1);
  38         }
  39
  40         return ret;
  41 }
  42
  43 static inline void icp_hv_set_cppr(u8 value)
  44 {
  45         long rc = plpar_hcall_norets(H_CPPR, value);
  46         if (rc != H_SUCCESS) {
  47                 pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
  48                         __func__, value, rc);
  49                 WARN_ON_ONCE(1);
  50         }
  51 }
  52
  53 static inline void icp_hv_set_xirr(unsigned int value)
  54 {
  55         long rc = plpar_hcall_norets(H_EOI, value);
  56         if (rc != H_SUCCESS) {
  57                 pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
  58                         __func__, value, rc);
  59                 WARN_ON_ONCE(1);
  60                 icp_hv_set_cppr(value >> 24);
  61         }
  62 }
  63
  64 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
  65 {
  66         int hw_cpu = get_hard_smp_processor_id(n_cpu);
  67         long rc;
  68
  69         /* Make sure all previous accesses are ordered before IPI sending */
  70         mb();
  71         rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
  72         if (rc != H_SUCCESS) {
  73                 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
  74                         "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
  75                 WARN_ON_ONCE(1);
  76         }
  77 }
  78
  79 static void icp_hv_eoi(struct irq_data *d)
  80 {
  81         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  82
  83         iosync();
  84         icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
  85 }
  86
  87 static void icp_hv_teardown_cpu(void)
  88 {
  89         int cpu = smp_processor_id();
  90
  91         /* Clear any pending IPI */
  92         icp_hv_set_qirr(cpu, 0xff);
  93 }
  94
  95 static void icp_hv_flush_ipi(void)
  96 {
  97         /* We take the ipi irq but and never return so we
  98          * need to EOI the IPI, but want to leave our priority 0
  99          *
 100          * should we check all the other interrupts too?
 101          * should we be flagging idle loop instead?
 102          * or creating some task to be scheduled?
 103          */
 104
 105         icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
 106 }
 107
 108 static unsigned int icp_hv_get_irq(void)
 109 {
 110         unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
 111         unsigned int vec = xirr & 0x00ffffff;
 112         unsigned int irq;
 113
 114         if (vec == XICS_IRQ_SPURIOUS)
 115                 return 0;
 116
 117         irq = irq_find_mapping(xics_host, vec);
 118         if (likely(irq)) {
 119                 xics_push_cppr(vec);
 120                 return irq;
 121         }
 122
 123         /* We don't have a linux mapping, so have rtas mask it. */
 124         xics_mask_unknown_vec(vec);
 125
 126         /* We might learn about it later, so EOI it */
 127         icp_hv_set_xirr(xirr);
 128
 129         return 0;
 130 }
 131
 132 static void icp_hv_set_cpu_priority(unsigned char cppr)
 133 {
 134         xics_set_base_cppr(cppr);
 135         icp_hv_set_cppr(cppr);
 136         iosync();
 137 }
 138
 139 #ifdef CONFIG_SMP
 140
 141 static void icp_hv_cause_ipi(int cpu)
 142 {
 143         icp_hv_set_qirr(cpu, IPI_PRIORITY);
 144 }
 145
 146 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
 147 {
 148         int cpu = smp_processor_id();
 149
 150         icp_hv_set_qirr(cpu, 0xff);
 151
 152         return smp_ipi_demux();
 153 }
 154
 155 #endif /* CONFIG_SMP */
 156
 157 static const struct icp_ops icp_hv_ops = {
 158         .get_irq        = icp_hv_get_irq,
 159         .eoi            = icp_hv_eoi,
 160         .set_priority   = icp_hv_set_cpu_priority,
 161         .teardown_cpu   = icp_hv_teardown_cpu,
 162         .flush_ipi      = icp_hv_flush_ipi,
 163 #ifdef CONFIG_SMP
 164         .ipi_action     = icp_hv_ipi_action,
 165         .cause_ipi      = icp_hv_cause_ipi,
 166 #endif
 167 };
 168
 169 int icp_hv_init(void)
 170 {
 171         struct device_node *np;
 172
 173         np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
 174         if (!np)
 175                 np = of_find_node_by_type(NULL,
 176                                     "PowerPC-External-Interrupt-Presentation");
 177         if (!np)
 178                 return -ENODEV;
 179
 180         icp_ops = &icp_hv_ops;
 181
 182         return 0;
 183 }
 184