arch/x86/pci/intel_mid_pci.c

   1 /*
   2  * Intel MID PCI support
   3  *   Copyright (c) 2008 Intel Corporation
   4  *     Jesse Barnes <jesse.barnes@intel.com>
   5  *
   6  * Moorestown has an interesting PCI implementation:
   7  *   - configuration space is memory mapped (as defined by MCFG)
   8  *   - Lincroft devices also have a real, type 1 configuration space
   9  *   - Early Lincroft silicon has a type 1 access bug that will cause
  10  *     a hang if non-existent devices are accessed
  11  *   - some devices have the "fixed BAR" capability, which means
  12  *     they can't be relocated or modified; check for that during
  13  *     BAR sizing
  14  *
  15  * So, we use the MCFG space for all reads and writes, but also send
  16  * Lincroft writes to type 1 space.  But only read/write if the device
  17  * actually exists, otherwise return all 1s for reads and bit bucket
  18  * the writes.
  19  */
  20
  21 #include <linux/sched.h>
  22 #include <linux/pci.h>
  23 #include <linux/ioport.h>
  24 #include <linux/init.h>
  25 #include <linux/dmi.h>
  26 #include <linux/acpi.h>
  27 #include <linux/io.h>
  28 #include <linux/smp.h>
  29
  30 #include <asm/segment.h>
  31 #include <asm/pci_x86.h>
  32 #include <asm/hw_irq.h>
  33 #include <asm/io_apic.h>
  34 #include <asm/intel-mid.h>
  35
  36 #define PCIE_CAP_OFFSET 0x100
  37
  38 /* Fixed BAR fields */
  39 #define PCIE_VNDR_CAP_ID_FIXED_BAR 0x00 /* Fixed BAR (TBD) */
  40 #define PCI_FIXED_BAR_0_SIZE    0x04
  41 #define PCI_FIXED_BAR_1_SIZE    0x08
  42 #define PCI_FIXED_BAR_2_SIZE    0x0c
  43 #define PCI_FIXED_BAR_3_SIZE    0x10
  44 #define PCI_FIXED_BAR_4_SIZE    0x14
  45 #define PCI_FIXED_BAR_5_SIZE    0x1c
  46
  47 static int pci_soc_mode;
  48
  49 /**
  50  * fixed_bar_cap - return the offset of the fixed BAR cap if found
  51  * @bus: PCI bus
  52  * @devfn: device in question
  53  *
  54  * Look for the fixed BAR cap on @bus and @devfn, returning its offset
  55  * if found or 0 otherwise.
  56  */
  57 static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn)
  58 {
  59         int pos;
  60         u32 pcie_cap = 0, cap_data;
  61
  62         pos = PCIE_CAP_OFFSET;
  63
  64         if (!raw_pci_ext_ops)
  65                 return 0;
  66
  67         while (pos) {
  68                 if (raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  69                                           devfn, pos, 4, &pcie_cap))
  70                         return 0;
  71
  72                 if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 ||
  73                         PCI_EXT_CAP_ID(pcie_cap) == 0xffff)
  74                         break;
  75
  76                 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) {
  77                         raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  78                                               devfn, pos + 4, 4, &cap_data);
  79                         if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR)
  80                                 return pos;
  81                 }
  82
  83                 pos = PCI_EXT_CAP_NEXT(pcie_cap);
  84         }
  85
  86         return 0;
  87 }
  88
  89 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn,
  90                                    int reg, int len, u32 val, int offset)
  91 {
  92         u32 size;
  93         unsigned int domain, busnum;
  94         int bar = (reg - PCI_BASE_ADDRESS_0) >> 2;
  95
  96         domain = pci_domain_nr(bus);
  97         busnum = bus->number;
  98
  99         if (val == ~0 && len == 4) {
 100                 unsigned long decode;
 101
 102                 raw_pci_ext_ops->read(domain, busnum, devfn,
 103                                offset + 8 + (bar * 4), 4, &size);
 104
 105                 /* Turn the size into a decode pattern for the sizing code */
 106                 if (size) {
 107                         decode = size - 1;
 108                         decode |= decode >> 1;
 109                         decode |= decode >> 2;
 110                         decode |= decode >> 4;
 111                         decode |= decode >> 8;
 112                         decode |= decode >> 16;
 113                         decode++;
 114                         decode = ~(decode - 1);
 115                 } else {
 116                         decode = 0;
 117                 }
 118
 119                 /*
 120                  * If val is all ones, the core code is trying to size the reg,
 121                  * so update the mmconfig space with the real size.
 122                  *
 123                  * Note: this assumes the fixed size we got is a power of two.
 124                  */
 125                 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4,
 126                                        decode);
 127         }
 128
 129         /* This is some other kind of BAR write, so just do it. */
 130         return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val);
 131 }
 132
 133 /**
 134  * type1_access_ok - check whether to use type 1
 135  * @bus: bus number
 136  * @devfn: device & function in question
 137  *
 138  * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at
 139  * all, the we can go ahead with any reads & writes.  If it's on a Lincroft,
 140  * but doesn't exist, avoid the access altogether to keep the chip from
 141  * hanging.
 142  */
 143 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg)
 144 {
 145         /*
 146          * This is a workaround for A0 LNC bug where PCI status register does
 147          * not have new CAP bit set. can not be written by SW either.
 148          *
 149          * PCI header type in real LNC indicates a single function device, this
 150          * will prevent probing other devices under the same function in PCI
 151          * shim. Therefore, use the header type in shim instead.
 152          */
 153         if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE)
 154                 return false;
 155         if (bus == 0 && (devfn == PCI_DEVFN(2, 0)
 156                                 || devfn == PCI_DEVFN(0, 0)
 157                                 || devfn == PCI_DEVFN(3, 0)))
 158                 return true;
 159         return false; /* Langwell on others */
 160 }
 161
 162 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 163                     int size, u32 *value)
 164 {
 165         if (type1_access_ok(bus->number, devfn, where))
 166                 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number,
 167                                         devfn, where, size, value);
 168         return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
 169                               devfn, where, size, value);
 170 }
 171
 172 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 173                      int size, u32 value)
 174 {
 175         int offset;
 176
 177         /*
 178          * On MRST, there is no PCI ROM BAR, this will cause a subsequent read
 179          * to ROM BAR return 0 then being ignored.
 180          */
 181         if (where == PCI_ROM_ADDRESS)
 182                 return 0;
 183
 184         /*
 185          * Devices with fixed BARs need special handling:
 186          *   - BAR sizing code will save, write ~0, read size, restore
 187          *   - so writes to fixed BARs need special handling
 188          *   - other writes to fixed BAR devices should go through mmconfig
 189          */
 190         offset = fixed_bar_cap(bus, devfn);
 191         if (offset &&
 192             (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) {
 193                 return pci_device_update_fixed(bus, devfn, where, size, value,
 194                                                offset);
 195         }
 196
 197         /*
 198          * On Moorestown update both real & mmconfig space
 199          * Note: early Lincroft silicon can't handle type 1 accesses to
 200          *       non-existent devices, so just eat the write in that case.
 201          */
 202         if (type1_access_ok(bus->number, devfn, where))
 203                 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number,
 204                                               devfn, where, size, value);
 205         return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn,
 206                                where, size, value);
 207 }
 208
 209 static int intel_mid_pci_irq_enable(struct pci_dev *dev)
 210 {
 211         struct irq_alloc_info info;
 212         int polarity;
 213
 214         if (dev->irq_managed && dev->irq > 0)
 215                 return 0;
 216
 217         if (intel_mid_identify_cpu() == INTEL_MID_CPU_CHIP_TANGIER)
 218                 polarity = 0; /* active high */
 219         else
 220                 polarity = 1; /* active low */
 221         ioapic_set_alloc_attr(&info, dev_to_node(&dev->dev), 1, polarity);
 222
 223         /*
 224          * MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to
 225          * IOAPIC RTE entries, so we just enable RTE for the device.
 226          */
 227         if (mp_map_gsi_to_irq(dev->irq, IOAPIC_MAP_ALLOC, &info) < 0)
 228                 return -EBUSY;
 229
 230         dev->irq_managed = 1;
 231
 232         return 0;
 233 }
 234
 235 static void intel_mid_pci_irq_disable(struct pci_dev *dev)
 236 {
 237         if (!mp_should_keep_irq(&dev->dev) && dev->irq_managed &&
 238             dev->irq > 0) {
 239                 mp_unmap_irq(dev->irq);
 240                 dev->irq_managed = 0;
 241         }
 242 }
 243
 244 struct pci_ops intel_mid_pci_ops = {
 245         .read = pci_read,
 246         .write = pci_write,
 247 };
 248
 249 /**
 250  * intel_mid_pci_init - installs intel_mid_pci_ops
 251  *
 252  * Moorestown has an interesting PCI implementation (see above).
 253  * Called when the early platform detection installs it.
 254  */
 255 int __init intel_mid_pci_init(void)
 256 {
 257         pr_info("Intel MID platform detected, using MID PCI ops\n");
 258         pci_mmcfg_late_init();
 259         pcibios_enable_irq = intel_mid_pci_irq_enable;
 260         pcibios_disable_irq = intel_mid_pci_irq_disable;
 261         pci_root_ops = intel_mid_pci_ops;
 262         pci_soc_mode = 1;
 263         /* Continue with standard init */
 264         return 1;
 265 }
 266
 267 /*
 268  * Langwell devices are not true PCI devices; they are not subject to 10 ms
 269  * d3 to d0 delay required by PCI spec.
 270  */
 271 static void pci_d3delay_fixup(struct pci_dev *dev)
 272 {
 273         /*
 274          * PCI fixups are effectively decided compile time. If we have a dual
 275          * SoC/non-SoC kernel we don't want to mangle d3 on non-SoC devices.
 276          */
 277         if (!pci_soc_mode)
 278                 return;
 279         /*
 280          * True PCI devices in Lincroft should allow type 1 access, the rest
 281          * are Langwell fake PCI devices.
 282          */
 283         if (type1_access_ok(dev->bus->number, dev->devfn, PCI_DEVICE_ID))
 284                 return;
 285         dev->d3_delay = 0;
 286 }
 287 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup);
 288
 289 static void mrst_power_off_unused_dev(struct pci_dev *dev)
 290 {
 291         pci_set_power_state(dev, PCI_D3hot);
 292 }
 293 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0801, mrst_power_off_unused_dev);
 294 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0809, mrst_power_off_unused_dev);
 295 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x080C, mrst_power_off_unused_dev);
 296 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0815, mrst_power_off_unused_dev);
 297
 298 /*
 299  * Langwell devices reside at fixed offsets, don't try to move them.
 300  */
 301 static void pci_fixed_bar_fixup(struct pci_dev *dev)
 302 {
 303         unsigned long offset;
 304         u32 size;
 305         int i;
 306
 307         if (!pci_soc_mode)
 308                 return;
 309
 310         /* Must have extended configuration space */
 311         if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
 312                 return;
 313
 314         /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 315         offset = fixed_bar_cap(dev->bus, dev->devfn);
 316         if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||
 317             PCI_DEVFN(2, 2) == dev->devfn)
 318                 return;
 319
 320         for (i = 0; i < PCI_ROM_RESOURCE; i++) {
 321                 pci_read_config_dword(dev, offset + 8 + (i * 4), &size);
 322                 dev->resource[i].end = dev->resource[i].start + size - 1;
 323                 dev->resource[i].flags |= IORESOURCE_PCI_FIXED;
 324         }
 325 }
 326 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup);