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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2011 IBM Corporation.
   4  */
   5 #include <linux/types.h>
   6 #include <linux/kernel.h>
   7 #include <linux/irq.h>
   8 #include <linux/smp.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/cpu.h>
  11 #include <linux/of.h>
  12
  13 #include <asm/smp.h>
  14 #include <asm/irq.h>
  15 #include <asm/errno.h>
  16 #include <asm/xics.h>
  17 #include <asm/io.h>
  18 #include <asm/hvcall.h>
  19
  20 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
  21 {
  22         unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
  23         long rc;
  24         unsigned int ret = XICS_IRQ_SPURIOUS;
  25
  26         rc = plpar_hcall(H_XIRR, retbuf, cppr);
  27         if (rc == H_SUCCESS) {
  28                 ret = (unsigned int)retbuf[0];
  29         } else {
  30                 pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
  31                         __func__, cppr, rc);
  32                 WARN_ON_ONCE(1);
  33         }
  34
  35         return ret;
  36 }
  37
  38 static inline void icp_hv_set_cppr(u8 value)
  39 {
  40         long rc = plpar_hcall_norets(H_CPPR, value);
  41         if (rc != H_SUCCESS) {
  42                 pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
  43                         __func__, value, rc);
  44                 WARN_ON_ONCE(1);
  45         }
  46 }
  47
  48 static inline void icp_hv_set_xirr(unsigned int value)
  49 {
  50         long rc = plpar_hcall_norets(H_EOI, value);
  51         if (rc != H_SUCCESS) {
  52                 pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
  53                         __func__, value, rc);
  54                 WARN_ON_ONCE(1);
  55                 icp_hv_set_cppr(value >> 24);
  56         }
  57 }
  58
  59 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
  60 {
  61         int hw_cpu = get_hard_smp_processor_id(n_cpu);
  62         long rc;
  63
  64         /* Make sure all previous accesses are ordered before IPI sending */
  65         mb();
  66         rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
  67         if (rc != H_SUCCESS) {
  68                 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
  69                         "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
  70                 WARN_ON_ONCE(1);
  71         }
  72 }
  73
  74 static void icp_hv_eoi(struct irq_data *d)
  75 {
  76         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  77
  78         iosync();
  79         icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
  80 }
  81
  82 static void icp_hv_teardown_cpu(void)
  83 {
  84         int cpu = smp_processor_id();
  85
  86         /* Clear any pending IPI */
  87         icp_hv_set_qirr(cpu, 0xff);
  88 }
  89
  90 static void icp_hv_flush_ipi(void)
  91 {
  92         /* We take the ipi irq but and never return so we
  93          * need to EOI the IPI, but want to leave our priority 0
  94          *
  95          * should we check all the other interrupts too?
  96          * should we be flagging idle loop instead?
  97          * or creating some task to be scheduled?
  98          */
  99
 100         icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
 101 }
 102
 103 static unsigned int icp_hv_get_irq(void)
 104 {
 105         unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
 106         unsigned int vec = xirr & 0x00ffffff;
 107         unsigned int irq;
 108
 109         if (vec == XICS_IRQ_SPURIOUS)
 110                 return 0;
 111
 112         irq = irq_find_mapping(xics_host, vec);
 113         if (likely(irq)) {
 114                 xics_push_cppr(vec);
 115                 return irq;
 116         }
 117
 118         /* We don't have a linux mapping, so have rtas mask it. */
 119         xics_mask_unknown_vec(vec);
 120
 121         /* We might learn about it later, so EOI it */
 122         icp_hv_set_xirr(xirr);
 123
 124         return 0;
 125 }
 126
 127 static void icp_hv_set_cpu_priority(unsigned char cppr)
 128 {
 129         xics_set_base_cppr(cppr);
 130         icp_hv_set_cppr(cppr);
 131         iosync();
 132 }
 133
 134 #ifdef CONFIG_SMP
 135
 136 static void icp_hv_cause_ipi(int cpu)
 137 {
 138         icp_hv_set_qirr(cpu, IPI_PRIORITY);
 139 }
 140
 141 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
 142 {
 143         int cpu = smp_processor_id();
 144
 145         icp_hv_set_qirr(cpu, 0xff);
 146
 147         return smp_ipi_demux();
 148 }
 149
 150 #endif /* CONFIG_SMP */
 151
 152 static const struct icp_ops icp_hv_ops = {
 153         .get_irq        = icp_hv_get_irq,
 154         .eoi            = icp_hv_eoi,
 155         .set_priority   = icp_hv_set_cpu_priority,
 156         .teardown_cpu   = icp_hv_teardown_cpu,
 157         .flush_ipi      = icp_hv_flush_ipi,
 158 #ifdef CONFIG_SMP
 159         .ipi_action     = icp_hv_ipi_action,
 160         .cause_ipi      = icp_hv_cause_ipi,
 161 #endif
 162 };
 163
 164 int icp_hv_init(void)
 165 {
 166         struct device_node *np;
 167
 168         np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
 169         if (!np)
 170                 np = of_find_node_by_type(NULL,
 171                                     "PowerPC-External-Interrupt-Presentation");
 172         if (!np)
 173                 return -ENODEV;
 174
 175         icp_ops = &icp_hv_ops;
 176
 177         of_node_put(np);
 178         return 0;
 179 }
 180