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