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;
  69
  70         /* Make sure all previous accesses are ordered before IPI sending */
  71         mb();
  72         rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
  73         if (rc != H_SUCCESS) {
  74                 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
  75                         "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
  76                 WARN_ON_ONCE(1);
  77         }
  78 }
  79
  80 static void icp_hv_eoi(struct irq_data *d)
  81 {
  82         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  83
  84         iosync();
  85         icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
  86 }
  87
  88 static void icp_hv_teardown_cpu(void)
  89 {
  90         int cpu = smp_processor_id();
  91
  92         /* Clear any pending IPI */
  93         icp_hv_set_qirr(cpu, 0xff);
  94 }
  95
  96 static void icp_hv_flush_ipi(void)
  97 {
  98         /* We take the ipi irq but and never return so we
  99          * need to EOI the IPI, but want to leave our priority 0
 100          *
 101          * should we check all the other interrupts too?
 102          * should we be flagging idle loop instead?
 103          * or creating some task to be scheduled?
 104          */
 105
 106         icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
 107 }
 108
 109 static unsigned int icp_hv_get_irq(void)
 110 {
 111         unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
 112         unsigned int vec = xirr & 0x00ffffff;
 113         unsigned int irq;
 114
 115         if (vec == XICS_IRQ_SPURIOUS)
 116                 return NO_IRQ;
 117
 118         irq = irq_find_mapping(xics_host, vec);
 119         if (likely(irq != NO_IRQ)) {
 120                 xics_push_cppr(vec);
 121                 return irq;
 122         }
 123
 124         /* We don't have a linux mapping, so have rtas mask it. */
 125         xics_mask_unknown_vec(vec);
 126
 127         /* We might learn about it later, so EOI it */
 128         icp_hv_set_xirr(xirr);
 129
 130         return NO_IRQ;
 131 }
 132
 133 static void icp_hv_set_cpu_priority(unsigned char cppr)
 134 {
 135         xics_set_base_cppr(cppr);
 136         icp_hv_set_cppr(cppr);
 137         iosync();
 138 }
 139
 140 #ifdef CONFIG_SMP
 141
 142 static void icp_hv_cause_ipi(int cpu, unsigned long data)
 143 {
 144         icp_hv_set_qirr(cpu, IPI_PRIORITY);
 145 }
 146
 147 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
 148 {
 149         int cpu = smp_processor_id();
 150
 151         icp_hv_set_qirr(cpu, 0xff);
 152
 153         return smp_ipi_demux();
 154 }
 155
 156 #endif /* CONFIG_SMP */
 157
 158 static const struct icp_ops icp_hv_ops = {
 159         .get_irq        = icp_hv_get_irq,
 160         .eoi            = icp_hv_eoi,
 161         .set_priority   = icp_hv_set_cpu_priority,
 162         .teardown_cpu   = icp_hv_teardown_cpu,
 163         .flush_ipi      = icp_hv_flush_ipi,
 164 #ifdef CONFIG_SMP
 165         .ipi_action     = icp_hv_ipi_action,
 166         .cause_ipi      = icp_hv_cause_ipi,
 167 #endif
 168 };
 169
 170 int icp_hv_init(void)
 171 {
 172         struct device_node *np;
 173
 174         np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
 175         if (!np)
 176                 np = of_find_node_by_type(NULL,
 177                                     "PowerPC-External-Interrupt-Presentation");
 178         if (!np)
 179                 return -ENODEV;
 180
 181         icp_ops = &icp_hv_ops;
 182
 183         return 0;
 184 }
 185