drivers/misc/cxl/vphb.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright 2014 IBM Corp.
   4  */
   5
   6 #include <linux/pci.h>
   7 #include <misc/cxl.h>
   8 #include "cxl.h"
   9
  10 static int cxl_pci_probe_mode(struct pci_bus *bus)
  11 {
  12         return PCI_PROBE_NORMAL;
  13 }
  14
  15 static int cxl_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
  16 {
  17         return -ENODEV;
  18 }
  19
  20 static void cxl_teardown_msi_irqs(struct pci_dev *pdev)
  21 {
  22         /*
  23          * MSI should never be set but need still need to provide this call
  24          * back.
  25          */
  26 }
  27
  28 static bool cxl_pci_enable_device_hook(struct pci_dev *dev)
  29 {
  30         struct pci_controller *phb;
  31         struct cxl_afu *afu;
  32         struct cxl_context *ctx;
  33
  34         phb = pci_bus_to_host(dev->bus);
  35         afu = (struct cxl_afu *)phb->private_data;
  36
  37         if (!cxl_ops->link_ok(afu->adapter, afu)) {
  38                 dev_warn(&dev->dev, "%s: Device link is down, refusing to enable AFU\n", __func__);
  39                 return false;
  40         }
  41
  42         dev->dev.archdata.dma_offset = PAGE_OFFSET;
  43
  44         /*
  45          * Allocate a context to do cxl things too.  If we eventually do real
  46          * DMA ops, we'll need a default context to attach them to
  47          */
  48         ctx = cxl_dev_context_init(dev);
  49         if (IS_ERR(ctx))
  50                 return false;
  51         dev->dev.archdata.cxl_ctx = ctx;
  52
  53         return (cxl_ops->afu_check_and_enable(afu) == 0);
  54 }
  55
  56 static void cxl_pci_disable_device(struct pci_dev *dev)
  57 {
  58         struct cxl_context *ctx = cxl_get_context(dev);
  59
  60         if (ctx) {
  61                 if (ctx->status == STARTED) {
  62                         dev_err(&dev->dev, "Default context started\n");
  63                         return;
  64                 }
  65                 dev->dev.archdata.cxl_ctx = NULL;
  66                 cxl_release_context(ctx);
  67         }
  68 }
  69
  70 static resource_size_t cxl_pci_window_alignment(struct pci_bus *bus,
  71                                                 unsigned long type)
  72 {
  73         return 1;
  74 }
  75
  76 static void cxl_pci_reset_secondary_bus(struct pci_dev *dev)
  77 {
  78         /* Should we do an AFU reset here ? */
  79 }
  80
  81 static int cxl_pcie_cfg_record(u8 bus, u8 devfn)
  82 {
  83         return (bus << 8) + devfn;
  84 }
  85
  86 static inline struct cxl_afu *pci_bus_to_afu(struct pci_bus *bus)
  87 {
  88         struct pci_controller *phb = bus ? pci_bus_to_host(bus) : NULL;
  89
  90         return phb ? phb->private_data : NULL;
  91 }
  92
  93 static void cxl_afu_configured_put(struct cxl_afu *afu)
  94 {
  95         atomic_dec_if_positive(&afu->configured_state);
  96 }
  97
  98 static bool cxl_afu_configured_get(struct cxl_afu *afu)
  99 {
 100         return atomic_inc_unless_negative(&afu->configured_state);
 101 }
 102
 103 static inline int cxl_pcie_config_info(struct pci_bus *bus, unsigned int devfn,
 104                                        struct cxl_afu *afu, int *_record)
 105 {
 106         int record;
 107
 108         record = cxl_pcie_cfg_record(bus->number, devfn);
 109         if (record > afu->crs_num)
 110                 return PCIBIOS_DEVICE_NOT_FOUND;
 111
 112         *_record = record;
 113         return 0;
 114 }
 115
 116 static int cxl_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
 117                                 int offset, int len, u32 *val)
 118 {
 119         int rc, record;
 120         struct cxl_afu *afu;
 121         u8 val8;
 122         u16 val16;
 123         u32 val32;
 124
 125         afu = pci_bus_to_afu(bus);
 126         /* Grab a reader lock on afu. */
 127         if (afu == NULL || !cxl_afu_configured_get(afu))
 128                 return PCIBIOS_DEVICE_NOT_FOUND;
 129
 130         rc = cxl_pcie_config_info(bus, devfn, afu, &record);
 131         if (rc)
 132                 goto out;
 133
 134         switch (len) {
 135         case 1:
 136                 rc = cxl_ops->afu_cr_read8(afu, record, offset, &val8);
 137                 *val = val8;
 138                 break;
 139         case 2:
 140                 rc = cxl_ops->afu_cr_read16(afu, record, offset, &val16);
 141                 *val = val16;
 142                 break;
 143         case 4:
 144                 rc = cxl_ops->afu_cr_read32(afu, record, offset, &val32);
 145                 *val = val32;
 146                 break;
 147         default:
 148                 WARN_ON(1);
 149         }
 150
 151 out:
 152         cxl_afu_configured_put(afu);
 153         return rc ? PCIBIOS_DEVICE_NOT_FOUND : 0;
 154 }
 155
 156 static int cxl_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
 157                                  int offset, int len, u32 val)
 158 {
 159         int rc, record;
 160         struct cxl_afu *afu;
 161
 162         afu = pci_bus_to_afu(bus);
 163         /* Grab a reader lock on afu. */
 164         if (afu == NULL || !cxl_afu_configured_get(afu))
 165                 return PCIBIOS_DEVICE_NOT_FOUND;
 166
 167         rc = cxl_pcie_config_info(bus, devfn, afu, &record);
 168         if (rc)
 169                 goto out;
 170
 171         switch (len) {
 172         case 1:
 173                 rc = cxl_ops->afu_cr_write8(afu, record, offset, val & 0xff);
 174                 break;
 175         case 2:
 176                 rc = cxl_ops->afu_cr_write16(afu, record, offset, val & 0xffff);
 177                 break;
 178         case 4:
 179                 rc = cxl_ops->afu_cr_write32(afu, record, offset, val);
 180                 break;
 181         default:
 182                 WARN_ON(1);
 183         }
 184
 185 out:
 186         cxl_afu_configured_put(afu);
 187         return rc ? PCIBIOS_SET_FAILED : 0;
 188 }
 189
 190 static struct pci_ops cxl_pcie_pci_ops =
 191 {
 192         .read = cxl_pcie_read_config,
 193         .write = cxl_pcie_write_config,
 194 };
 195
 196
 197 static struct pci_controller_ops cxl_pci_controller_ops =
 198 {
 199         .probe_mode = cxl_pci_probe_mode,
 200         .enable_device_hook = cxl_pci_enable_device_hook,
 201         .disable_device = cxl_pci_disable_device,
 202         .release_device = cxl_pci_disable_device,
 203         .window_alignment = cxl_pci_window_alignment,
 204         .reset_secondary_bus = cxl_pci_reset_secondary_bus,
 205         .setup_msi_irqs = cxl_setup_msi_irqs,
 206         .teardown_msi_irqs = cxl_teardown_msi_irqs,
 207 };
 208
 209 int cxl_pci_vphb_add(struct cxl_afu *afu)
 210 {
 211         struct pci_controller *phb;
 212         struct device_node *vphb_dn;
 213         struct device *parent;
 214
 215         /*
 216          * If there are no AFU configuration records we won't have anything to
 217          * expose under the vPHB, so skip creating one, returning success since
 218          * this is still a valid case. This will also opt us out of EEH
 219          * handling since we won't have anything special to do if there are no
 220          * kernel drivers attached to the vPHB, and EEH handling is not yet
 221          * supported in the peer model.
 222          */
 223         if (!afu->crs_num)
 224                 return 0;
 225
 226         /* The parent device is the adapter. Reuse the device node of
 227          * the adapter.
 228          * We don't seem to care what device node is used for the vPHB,
 229          * but tools such as lsvpd walk up the device parents looking
 230          * for a valid location code, so we might as well show devices
 231          * attached to the adapter as being located on that adapter.
 232          */
 233         parent = afu->adapter->dev.parent;
 234         vphb_dn = parent->of_node;
 235
 236         /* Alloc and setup PHB data structure */
 237         phb = pcibios_alloc_controller(vphb_dn);
 238         if (!phb)
 239                 return -ENODEV;
 240
 241         /* Setup parent in sysfs */
 242         phb->parent = parent;
 243
 244         /* Setup the PHB using arch provided callback */
 245         phb->ops = &cxl_pcie_pci_ops;
 246         phb->cfg_addr = NULL;
 247         phb->cfg_data = NULL;
 248         phb->private_data = afu;
 249         phb->controller_ops = cxl_pci_controller_ops;
 250
 251         /* Scan the bus */
 252         pcibios_scan_phb(phb);
 253         if (phb->bus == NULL)
 254                 return -ENXIO;
 255
 256         /* Set release hook on root bus */
 257         pci_set_host_bridge_release(to_pci_host_bridge(phb->bus->bridge),
 258                                     pcibios_free_controller_deferred,
 259                                     (void *) phb);
 260
 261         /* Claim resources. This might need some rework as well depending
 262          * whether we are doing probe-only or not, like assigning unassigned
 263          * resources etc...
 264          */
 265         pcibios_claim_one_bus(phb->bus);
 266
 267         /* Add probed PCI devices to the device model */
 268         pci_bus_add_devices(phb->bus);
 269
 270         afu->phb = phb;
 271
 272         return 0;
 273 }
 274
 275 void cxl_pci_vphb_remove(struct cxl_afu *afu)
 276 {
 277         struct pci_controller *phb;
 278
 279         /* If there is no configuration record we won't have one of these */
 280         if (!afu || !afu->phb)
 281                 return;
 282
 283         phb = afu->phb;
 284         afu->phb = NULL;
 285
 286         pci_remove_root_bus(phb->bus);
 287         /*
 288          * We don't free phb here - that's handled by
 289          * pcibios_free_controller_deferred()
 290          */
 291 }
 292
 293 bool cxl_pci_is_vphb_device(struct pci_dev *dev)
 294 {
 295         struct pci_controller *phb;
 296
 297         phb = pci_bus_to_host(dev->bus);
 298
 299         return (phb->ops == &cxl_pcie_pci_ops);
 300 }
 301
 302 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev)
 303 {
 304         struct pci_controller *phb;
 305
 306         phb = pci_bus_to_host(dev->bus);
 307
 308         return (struct cxl_afu *)phb->private_data;
 309 }
 310 EXPORT_SYMBOL_GPL(cxl_pci_to_afu);
 311
 312 unsigned int cxl_pci_to_cfg_record(struct pci_dev *dev)
 313 {
 314         return cxl_pcie_cfg_record(dev->bus->number, dev->devfn);
 315 }
 316 EXPORT_SYMBOL_GPL(cxl_pci_to_cfg_record);