arch/powerpc/sysdev/xics/ics-rtas.c

   1 #include <linux/types.h>
   2 #include <linux/kernel.h>
   3 #include <linux/irq.h>
   4 #include <linux/smp.h>
   5 #include <linux/interrupt.h>
   6 #include <linux/init.h>
   7 #include <linux/cpu.h>
   8 #include <linux/of.h>
   9 #include <linux/spinlock.h>
  10 #include <linux/msi.h>
  11
  12 #include <asm/prom.h>
  13 #include <asm/smp.h>
  14 #include <asm/machdep.h>
  15 #include <asm/irq.h>
  16 #include <asm/errno.h>
  17 #include <asm/xics.h>
  18 #include <asm/rtas.h>
  19
  20 /* RTAS service tokens */
  21 static int ibm_get_xive;
  22 static int ibm_set_xive;
  23 static int ibm_int_on;
  24 static int ibm_int_off;
  25
  26 static int ics_rtas_map(struct ics *ics, unsigned int virq);
  27 static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec);
  28 static long ics_rtas_get_server(struct ics *ics, unsigned long vec);
  29 static int ics_rtas_host_match(struct ics *ics, struct device_node *node);
  30
  31 /* Only one global & state struct ics */
  32 static struct ics ics_rtas = {
  33         .map            = ics_rtas_map,
  34         .mask_unknown   = ics_rtas_mask_unknown,
  35         .get_server     = ics_rtas_get_server,
  36         .host_match     = ics_rtas_host_match,
  37 };
  38
  39 static void ics_rtas_unmask_irq(struct irq_data *d)
  40 {
  41         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
  42         int call_status;
  43         int server;
  44
  45         pr_devel("xics: unmask virq %d [hw 0x%x]\n", d->irq, hw_irq);
  46
  47         if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
  48                 return;
  49
  50         server = xics_get_irq_server(d->irq, d->affinity, 0);
  51
  52         call_status = rtas_call(ibm_set_xive, 3, 1, NULL, hw_irq, server,
  53                                 DEFAULT_PRIORITY);
  54         if (call_status != 0) {
  55                 printk(KERN_ERR
  56                         "%s: ibm_set_xive irq %u server %x returned %d\n",
  57                         __func__, hw_irq, server, call_status);
  58                 return;
  59         }
  60
  61         /* Now unmask the interrupt (often a no-op) */
  62         call_status = rtas_call(ibm_int_on, 1, 1, NULL, hw_irq);
  63         if (call_status != 0) {
  64                 printk(KERN_ERR "%s: ibm_int_on irq=%u returned %d\n",
  65                         __func__, hw_irq, call_status);
  66                 return;
  67         }
  68 }
  69
  70 static unsigned int ics_rtas_startup(struct irq_data *d)
  71 {
  72 #ifdef CONFIG_PCI_MSI
  73         /*
  74          * The generic MSI code returns with the interrupt disabled on the
  75          * card, using the MSI mask bits. Firmware doesn't appear to unmask
  76          * at that level, so we do it here by hand.
  77          */
  78         if (d->msi_desc)
  79                 unmask_msi_irq(d);
  80 #endif
  81         /* unmask it */
  82         ics_rtas_unmask_irq(d);
  83         return 0;
  84 }
  85
  86 static void ics_rtas_mask_real_irq(unsigned int hw_irq)
  87 {
  88         int call_status;
  89
  90         if (hw_irq == XICS_IPI)
  91                 return;
  92
  93         call_status = rtas_call(ibm_int_off, 1, 1, NULL, hw_irq);
  94         if (call_status != 0) {
  95                 printk(KERN_ERR "%s: ibm_int_off irq=%u returned %d\n",
  96                         __func__, hw_irq, call_status);
  97                 return;
  98         }
  99
 100         /* Have to set XIVE to 0xff to be able to remove a slot */
 101         call_status = rtas_call(ibm_set_xive, 3, 1, NULL, hw_irq,
 102                                 xics_default_server, 0xff);
 103         if (call_status != 0) {
 104                 printk(KERN_ERR "%s: ibm_set_xive(0xff) irq=%u returned %d\n",
 105                         __func__, hw_irq, call_status);
 106                 return;
 107         }
 108 }
 109
 110 static void ics_rtas_mask_irq(struct irq_data *d)
 111 {
 112         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
 113
 114         pr_devel("xics: mask virq %d [hw 0x%x]\n", d->irq, hw_irq);
 115
 116         if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
 117                 return;
 118         ics_rtas_mask_real_irq(hw_irq);
 119 }
 120
 121 static int ics_rtas_set_affinity(struct irq_data *d,
 122                                  const struct cpumask *cpumask,
 123                                  bool force)
 124 {
 125         unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
 126         int status;
 127         int xics_status[2];
 128         int irq_server;
 129
 130         if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
 131                 return -1;
 132
 133         status = rtas_call(ibm_get_xive, 1, 3, xics_status, hw_irq);
 134
 135         if (status) {
 136                 printk(KERN_ERR "%s: ibm,get-xive irq=%u returns %d\n",
 137                         __func__, hw_irq, status);
 138                 return -1;
 139         }
 140
 141         irq_server = xics_get_irq_server(d->irq, cpumask, 1);
 142         if (irq_server == -1) {
 143                 char cpulist[128];
 144                 cpumask_scnprintf(cpulist, sizeof(cpulist), cpumask);
 145                 printk(KERN_WARNING
 146                         "%s: No online cpus in the mask %s for irq %d\n",
 147                         __func__, cpulist, d->irq);
 148                 return -1;
 149         }
 150
 151         status = rtas_call(ibm_set_xive, 3, 1, NULL,
 152                            hw_irq, irq_server, xics_status[1]);
 153
 154         if (status) {
 155                 printk(KERN_ERR "%s: ibm,set-xive irq=%u returns %d\n",
 156                         __func__, hw_irq, status);
 157                 return -1;
 158         }
 159
 160         return IRQ_SET_MASK_OK;
 161 }
 162
 163 static struct irq_chip ics_rtas_irq_chip = {
 164         .name = "XICS",
 165         .irq_startup = ics_rtas_startup,
 166         .irq_mask = ics_rtas_mask_irq,
 167         .irq_unmask = ics_rtas_unmask_irq,
 168         .irq_eoi = NULL, /* Patched at init time */
 169         .irq_set_affinity = ics_rtas_set_affinity
 170 };
 171
 172 static int ics_rtas_map(struct ics *ics, unsigned int virq)
 173 {
 174         unsigned int hw_irq = (unsigned int)virq_to_hw(virq);
 175         int status[2];
 176         int rc;
 177
 178         if (WARN_ON(hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS))
 179                 return -EINVAL;
 180
 181         /* Check if RTAS knows about this interrupt */
 182         rc = rtas_call(ibm_get_xive, 1, 3, status, hw_irq);
 183         if (rc)
 184                 return -ENXIO;
 185
 186         irq_set_chip_and_handler(virq, &ics_rtas_irq_chip, handle_fasteoi_irq);
 187         irq_set_chip_data(virq, &ics_rtas);
 188
 189         return 0;
 190 }
 191
 192 static void ics_rtas_mask_unknown(struct ics *ics, unsigned long vec)
 193 {
 194         ics_rtas_mask_real_irq(vec);
 195 }
 196
 197 static long ics_rtas_get_server(struct ics *ics, unsigned long vec)
 198 {
 199         int rc, status[2];
 200
 201         rc = rtas_call(ibm_get_xive, 1, 3, status, vec);
 202         if (rc)
 203                 return -1;
 204         return status[0];
 205 }
 206
 207 static int ics_rtas_host_match(struct ics *ics, struct device_node *node)
 208 {
 209         /* IBM machines have interrupt parents of various funky types for things
 210          * like vdevices, events, etc... The trick we use here is to match
 211          * everything here except the legacy 8259 which is compatible "chrp,iic"
 212          */
 213         return !of_device_is_compatible(node, "chrp,iic");
 214 }
 215
 216 int ics_rtas_init(void)
 217 {
 218         ibm_get_xive = rtas_token("ibm,get-xive");
 219         ibm_set_xive = rtas_token("ibm,set-xive");
 220         ibm_int_on  = rtas_token("ibm,int-on");
 221         ibm_int_off = rtas_token("ibm,int-off");
 222
 223         /* We enable the RTAS "ICS" if RTAS is present with the
 224          * appropriate tokens
 225          */
 226         if (ibm_get_xive == RTAS_UNKNOWN_SERVICE ||
 227             ibm_set_xive == RTAS_UNKNOWN_SERVICE)
 228                 return -ENODEV;
 229
 230         /* We need to patch our irq chip's EOI to point to the
 231          * right ICP
 232          */
 233         ics_rtas_irq_chip.irq_eoi = icp_ops->eoi;
 234
 235         /* Register ourselves */
 236         xics_register_ics(&ics_rtas);
 237
 238         return 0;
 239 }
 240