arch/powerpc/platforms/pseries/msi.c

   1 /*
   2  * Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
   3  * Copyright 2006-2007 Michael Ellerman, IBM Corp.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; version 2 of the
   8  * License.
   9  *
  10  */
  11
  12 #include <linux/device.h>
  13 #include <linux/irq.h>
  14 #include <linux/msi.h>
  15
  16 #include <asm/rtas.h>
  17 #include <asm/hw_irq.h>
  18 #include <asm/ppc-pci.h>
  19
  20 static int query_token, change_token;
  21
  22 #define RTAS_QUERY_FN           0
  23 #define RTAS_CHANGE_FN          1
  24 #define RTAS_RESET_FN           2
  25 #define RTAS_CHANGE_MSI_FN      3
  26 #define RTAS_CHANGE_MSIX_FN     4
  27
  28 static struct pci_dn *get_pdn(struct pci_dev *pdev)
  29 {
  30         struct device_node *dn;
  31         struct pci_dn *pdn;
  32
  33         dn = pci_device_to_OF_node(pdev);
  34         if (!dn) {
  35                 dev_dbg(&pdev->dev, "rtas_msi: No OF device node\n");
  36                 return NULL;
  37         }
  38
  39         pdn = PCI_DN(dn);
  40         if (!pdn) {
  41                 dev_dbg(&pdev->dev, "rtas_msi: No PCI DN\n");
  42                 return NULL;
  43         }
  44
  45         return pdn;
  46 }
  47
  48 /* RTAS Helpers */
  49
  50 static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
  51 {
  52         u32 addr, seq_num, rtas_ret[3];
  53         unsigned long buid;
  54         int rc;
  55
  56         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
  57         buid = pdn->phb->buid;
  58
  59         seq_num = 1;
  60         do {
  61                 if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN)
  62                         rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
  63                                         BUID_HI(buid), BUID_LO(buid),
  64                                         func, num_irqs, seq_num);
  65                 else
  66                         rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
  67                                         BUID_HI(buid), BUID_LO(buid),
  68                                         func, num_irqs, seq_num);
  69
  70                 seq_num = rtas_ret[1];
  71         } while (rtas_busy_delay(rc));
  72
  73         if (rc == 0) /* Success */
  74                 rc = rtas_ret[0];
  75
  76         pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d) = (%d)\n",
  77                  func, num_irqs, rc);
  78
  79         return rc;
  80 }
  81
  82 static void rtas_disable_msi(struct pci_dev *pdev)
  83 {
  84         struct pci_dn *pdn;
  85
  86         pdn = get_pdn(pdev);
  87         if (!pdn)
  88                 return;
  89
  90         if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0)
  91                 pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
  92 }
  93
  94 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
  95 {
  96         u32 addr, rtas_ret[2];
  97         unsigned long buid;
  98         int rc;
  99
 100         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
 101         buid = pdn->phb->buid;
 102
 103         do {
 104                 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
 105                                BUID_HI(buid), BUID_LO(buid), offset);
 106         } while (rtas_busy_delay(rc));
 107
 108         if (rc) {
 109                 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
 110                 return rc;
 111         }
 112
 113         return rtas_ret[0];
 114 }
 115
 116 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 117 {
 118         struct msi_desc *entry;
 119
 120         list_for_each_entry(entry, &pdev->msi_list, list) {
 121                 if (entry->irq == NO_IRQ)
 122                         continue;
 123
 124                 set_irq_msi(entry->irq, NULL);
 125                 irq_dispose_mapping(entry->irq);
 126         }
 127
 128         rtas_disable_msi(pdev);
 129 }
 130
 131 static int check_req_msi(struct pci_dev *pdev, int nvec)
 132 {
 133         struct device_node *dn;
 134         struct pci_dn *pdn;
 135         const u32 *req_msi;
 136
 137         pdn = get_pdn(pdev);
 138         if (!pdn)
 139                 return -ENODEV;
 140
 141         dn = pdn->node;
 142
 143         req_msi = of_get_property(dn, "ibm,req#msi", NULL);
 144         if (!req_msi) {
 145                 pr_debug("rtas_msi: No ibm,req#msi on %s\n", dn->full_name);
 146                 return -ENOENT;
 147         }
 148
 149         if (*req_msi < nvec) {
 150                 pr_debug("rtas_msi: ibm,req#msi requests < %d MSIs\n", nvec);
 151                 return -ENOSPC;
 152         }
 153
 154         return 0;
 155 }
 156
 157 static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
 158 {
 159         if (type == PCI_CAP_ID_MSIX)
 160                 pr_debug("rtas_msi: MSI-X untested, trying anyway.\n");
 161
 162         return check_req_msi(pdev, nvec);
 163 }
 164
 165 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 166 {
 167         struct pci_dn *pdn;
 168         int hwirq, virq, i, rc;
 169         struct msi_desc *entry;
 170
 171         pdn = get_pdn(pdev);
 172         if (!pdn)
 173                 return -ENODEV;
 174
 175         /*
 176          * Try the new more explicit firmware interface, if that fails fall
 177          * back to the old interface. The old interface is known to never
 178          * return MSI-Xs.
 179          */
 180         if (type == PCI_CAP_ID_MSI) {
 181                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
 182
 183                 if (rc != nvec) {
 184                         pr_debug("rtas_msi: trying the old firmware call.\n");
 185                         rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
 186                 }
 187         } else
 188                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
 189
 190         if (rc != nvec) {
 191                 pr_debug("rtas_msi: rtas_change_msi() failed\n");
 192
 193                 /*
 194                  * In case of an error it's not clear whether the device is
 195                  * left with MSI enabled or not, so we explicitly disable.
 196                  */
 197                 goto out_free;
 198         }
 199
 200         i = 0;
 201         list_for_each_entry(entry, &pdev->msi_list, list) {
 202                 hwirq = rtas_query_irq_number(pdn, i);
 203                 if (hwirq < 0) {
 204                         rc = hwirq;
 205                         pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
 206                         goto out_free;
 207                 }
 208
 209                 virq = irq_create_mapping(NULL, hwirq);
 210
 211                 if (virq == NO_IRQ) {
 212                         pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
 213                         rc = -ENOSPC;
 214                         goto out_free;
 215                 }
 216
 217                 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 218                 set_irq_msi(virq, entry);
 219                 unmask_msi_irq(virq);
 220         }
 221
 222         return 0;
 223
 224  out_free:
 225         rtas_teardown_msi_irqs(pdev);
 226         return rc;
 227 }
 228
 229 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
 230 {
 231         /* No LSI -> leave MSIs (if any) configured */
 232         if (pdev->irq == NO_IRQ) {
 233                 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
 234                 return;
 235         }
 236
 237         /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
 238         if (check_req_msi(pdev, 1)) {
 239                 dev_dbg(&pdev->dev, "rtas_msi: no req#msi, nothing to do.\n");
 240                 return;
 241         }
 242
 243         dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
 244         rtas_disable_msi(pdev);
 245 }
 246
 247 static int rtas_msi_init(void)
 248 {
 249         query_token  = rtas_token("ibm,query-interrupt-source-number");
 250         change_token = rtas_token("ibm,change-msi");
 251
 252         if ((query_token == RTAS_UNKNOWN_SERVICE) ||
 253                         (change_token == RTAS_UNKNOWN_SERVICE)) {
 254                 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
 255                 return -1;
 256         }
 257
 258         pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
 259
 260         WARN_ON(ppc_md.setup_msi_irqs);
 261         ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
 262         ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
 263         ppc_md.msi_check_device = rtas_msi_check_device;
 264
 265         WARN_ON(ppc_md.pci_irq_fixup);
 266         ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
 267
 268         return 0;
 269 }
 270 arch_initcall(rtas_msi_init);