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         /*
  74          * If the RTAS call succeeded, return the number of irqs allocated.
  75          * If not, make sure we return a negative error code.
  76          */
  77         if (rc == 0)
  78                 rc = rtas_ret[0];
  79         else if (rc > 0)
  80                 rc = -rc;
  81
  82         pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
  83                  func, num_irqs, rtas_ret[0], rc);
  84
  85         return rc;
  86 }
  87
  88 static void rtas_disable_msi(struct pci_dev *pdev)
  89 {
  90         struct pci_dn *pdn;
  91
  92         pdn = get_pdn(pdev);
  93         if (!pdn)
  94                 return;
  95
  96         if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0)
  97                 pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
  98 }
  99
 100 static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
 101 {
 102         u32 addr, rtas_ret[2];
 103         unsigned long buid;
 104         int rc;
 105
 106         addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
 107         buid = pdn->phb->buid;
 108
 109         do {
 110                 rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
 111                                BUID_HI(buid), BUID_LO(buid), offset);
 112         } while (rtas_busy_delay(rc));
 113
 114         if (rc) {
 115                 pr_debug("rtas_msi: error (%d) querying source number\n", rc);
 116                 return rc;
 117         }
 118
 119         return rtas_ret[0];
 120 }
 121
 122 static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
 123 {
 124         struct msi_desc *entry;
 125
 126         list_for_each_entry(entry, &pdev->msi_list, list) {
 127                 if (entry->irq == NO_IRQ)
 128                         continue;
 129
 130                 set_irq_msi(entry->irq, NULL);
 131                 irq_dispose_mapping(entry->irq);
 132         }
 133
 134         rtas_disable_msi(pdev);
 135 }
 136
 137 static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
 138 {
 139         struct device_node *dn;
 140         struct pci_dn *pdn;
 141         const u32 *req_msi;
 142
 143         pdn = get_pdn(pdev);
 144         if (!pdn)
 145                 return -ENODEV;
 146
 147         dn = pdn->node;
 148
 149         req_msi = of_get_property(dn, prop_name, NULL);
 150         if (!req_msi) {
 151                 pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
 152                 return -ENOENT;
 153         }
 154
 155         if (*req_msi < nvec) {
 156                 pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
 157                 return -ENOSPC;
 158         }
 159
 160         return 0;
 161 }
 162
 163 static int check_req_msi(struct pci_dev *pdev, int nvec)
 164 {
 165         return check_req(pdev, nvec, "ibm,req#msi");
 166 }
 167
 168 static int check_req_msix(struct pci_dev *pdev, int nvec)
 169 {
 170         return check_req(pdev, nvec, "ibm,req#msi-x");
 171 }
 172
 173 static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
 174 {
 175         if (type == PCI_CAP_ID_MSIX)
 176                 return check_req_msix(pdev, nvec);
 177
 178         return check_req_msi(pdev, nvec);
 179 }
 180
 181 static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
 182 {
 183         struct pci_dn *pdn;
 184         int hwirq, virq, i, rc;
 185         struct msi_desc *entry;
 186         struct msi_msg msg;
 187
 188         pdn = get_pdn(pdev);
 189         if (!pdn)
 190                 return -ENODEV;
 191
 192         /*
 193          * Try the new more explicit firmware interface, if that fails fall
 194          * back to the old interface. The old interface is known to never
 195          * return MSI-Xs.
 196          */
 197         if (type == PCI_CAP_ID_MSI) {
 198                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
 199
 200                 if (rc < 0) {
 201                         pr_debug("rtas_msi: trying the old firmware call.\n");
 202                         rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
 203                 }
 204         } else
 205                 rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
 206
 207         if (rc != nvec) {
 208                 pr_debug("rtas_msi: rtas_change_msi() failed\n");
 209                 return rc;
 210         }
 211
 212         i = 0;
 213         list_for_each_entry(entry, &pdev->msi_list, list) {
 214                 hwirq = rtas_query_irq_number(pdn, i++);
 215                 if (hwirq < 0) {
 216                         pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
 217                         return hwirq;
 218                 }
 219
 220                 virq = irq_create_mapping(NULL, hwirq);
 221
 222                 if (virq == NO_IRQ) {
 223                         pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
 224                         return -ENOSPC;
 225                 }
 226
 227                 dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
 228                 set_irq_msi(virq, entry);
 229
 230                 /* Read config space back so we can restore after reset */
 231                 read_msi_msg(virq, &msg);
 232                 entry->msg = msg;
 233
 234                 unmask_msi_irq(virq);
 235         }
 236
 237         return 0;
 238 }
 239
 240 static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
 241 {
 242         /* No LSI -> leave MSIs (if any) configured */
 243         if (pdev->irq == NO_IRQ) {
 244                 dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
 245                 return;
 246         }
 247
 248         /* No MSI -> MSIs can't have been assigned by fw, leave LSI */
 249         if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
 250                 dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
 251                 return;
 252         }
 253
 254         dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
 255         rtas_disable_msi(pdev);
 256 }
 257
 258 static int rtas_msi_init(void)
 259 {
 260         query_token  = rtas_token("ibm,query-interrupt-source-number");
 261         change_token = rtas_token("ibm,change-msi");
 262
 263         if ((query_token == RTAS_UNKNOWN_SERVICE) ||
 264                         (change_token == RTAS_UNKNOWN_SERVICE)) {
 265                 pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
 266                 return -1;
 267         }
 268
 269         pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
 270
 271         WARN_ON(ppc_md.setup_msi_irqs);
 272         ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
 273         ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
 274         ppc_md.msi_check_device = rtas_msi_check_device;
 275
 276         WARN_ON(ppc_md.pci_irq_fixup);
 277         ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
 278
 279         return 0;
 280 }
 281 arch_initcall(rtas_msi_init);