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); 270