arch/x86/pci/mrst.c

   1 /*
   2  * Moorestown 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
  27 #include <asm/acpi.h>
  28 #include <asm/segment.h>
  29 #include <asm/io.h>
  30 #include <asm/smp.h>
  31 #include <asm/pci_x86.h>
  32 #include <asm/hw_irq.h>
  33 #include <asm/io_apic.h>
  34
  35 #define PCIE_CAP_OFFSET 0x100
  36
  37 /* Fixed BAR fields */
  38 #define PCIE_VNDR_CAP_ID_FIXED_BAR 0x00 /* Fixed BAR (TBD) */
  39 #define PCI_FIXED_BAR_0_SIZE    0x04
  40 #define PCI_FIXED_BAR_1_SIZE    0x08
  41 #define PCI_FIXED_BAR_2_SIZE    0x0c
  42 #define PCI_FIXED_BAR_3_SIZE    0x10
  43 #define PCI_FIXED_BAR_4_SIZE    0x14
  44 #define PCI_FIXED_BAR_5_SIZE    0x1c
  45
  46 /**
  47  * fixed_bar_cap - return the offset of the fixed BAR cap if found
  48  * @bus: PCI bus
  49  * @devfn: device in question
  50  *
  51  * Look for the fixed BAR cap on @bus and @devfn, returning its offset
  52  * if found or 0 otherwise.
  53  */
  54 static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn)
  55 {
  56         int pos;
  57         u32 pcie_cap = 0, cap_data;
  58
  59         pos = PCIE_CAP_OFFSET;
  60
  61         if (!raw_pci_ext_ops)
  62                 return 0;
  63
  64         while (pos) {
  65                 if (raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  66                                           devfn, pos, 4, &pcie_cap))
  67                         return 0;
  68
  69                 if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 ||
  70                         PCI_EXT_CAP_ID(pcie_cap) == 0xffff)
  71                         break;
  72
  73                 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) {
  74                         raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  75                                               devfn, pos + 4, 4, &cap_data);
  76                         if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR)
  77                                 return pos;
  78                 }
  79
  80                 pos = PCI_EXT_CAP_NEXT(pcie_cap);
  81         }
  82
  83         return 0;
  84 }
  85
  86 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn,
  87                                    int reg, int len, u32 val, int offset)
  88 {
  89         u32 size;
  90         unsigned int domain, busnum;
  91         int bar = (reg - PCI_BASE_ADDRESS_0) >> 2;
  92
  93         domain = pci_domain_nr(bus);
  94         busnum = bus->number;
  95
  96         if (val == ~0 && len == 4) {
  97                 unsigned long decode;
  98
  99                 raw_pci_ext_ops->read(domain, busnum, devfn,
 100                                offset + 8 + (bar * 4), 4, &size);
 101
 102                 /* Turn the size into a decode pattern for the sizing code */
 103                 if (size) {
 104                         decode = size - 1;
 105                         decode |= decode >> 1;
 106                         decode |= decode >> 2;
 107                         decode |= decode >> 4;
 108                         decode |= decode >> 8;
 109                         decode |= decode >> 16;
 110                         decode++;
 111                         decode = ~(decode - 1);
 112                 } else {
 113                         decode = 0;
 114                 }
 115
 116                 /*
 117                  * If val is all ones, the core code is trying to size the reg,
 118                  * so update the mmconfig space with the real size.
 119                  *
 120                  * Note: this assumes the fixed size we got is a power of two.
 121                  */
 122                 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4,
 123                                        decode);
 124         }
 125
 126         /* This is some other kind of BAR write, so just do it. */
 127         return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val);
 128 }
 129
 130 /**
 131  * type1_access_ok - check whether to use type 1
 132  * @bus: bus number
 133  * @devfn: device & function in question
 134  *
 135  * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at
 136  * all, the we can go ahead with any reads & writes.  If it's on a Lincroft,
 137  * but doesn't exist, avoid the access altogether to keep the chip from
 138  * hanging.
 139  */
 140 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg)
 141 {
 142         /* This is a workaround for A0 LNC bug where PCI status register does
 143          * not have new CAP bit set. can not be written by SW either.
 144          *
 145          * PCI header type in real LNC indicates a single function device, this
 146          * will prevent probing other devices under the same function in PCI
 147          * shim. Therefore, use the header type in shim instead.
 148          */
 149         if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE)
 150                 return 0;
 151         if (bus == 0 && (devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(0, 0)))
 152                 return 1;
 153         return 0; /* langwell on others */
 154 }
 155
 156 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 157                     int size, u32 *value)
 158 {
 159         if (type1_access_ok(bus->number, devfn, where))
 160                 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number,
 161                                         devfn, where, size, value);
 162         return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
 163                               devfn, where, size, value);
 164 }
 165
 166 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 167                      int size, u32 value)
 168 {
 169         int offset;
 170
 171         /* On MRST, there is no PCI ROM BAR, this will cause a subsequent read
 172          * to ROM BAR return 0 then being ignored.
 173          */
 174         if (where == PCI_ROM_ADDRESS)
 175                 return 0;
 176
 177         /*
 178          * Devices with fixed BARs need special handling:
 179          *   - BAR sizing code will save, write ~0, read size, restore
 180          *   - so writes to fixed BARs need special handling
 181          *   - other writes to fixed BAR devices should go through mmconfig
 182          */
 183         offset = fixed_bar_cap(bus, devfn);
 184         if (offset &&
 185             (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) {
 186                 return pci_device_update_fixed(bus, devfn, where, size, value,
 187                                                offset);
 188         }
 189
 190         /*
 191          * On Moorestown update both real & mmconfig space
 192          * Note: early Lincroft silicon can't handle type 1 accesses to
 193          *       non-existent devices, so just eat the write in that case.
 194          */
 195         if (type1_access_ok(bus->number, devfn, where))
 196                 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number,
 197                                               devfn, where, size, value);
 198         return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn,
 199                                where, size, value);
 200 }
 201
 202 static int mrst_pci_irq_enable(struct pci_dev *dev)
 203 {
 204         u8 pin;
 205         struct io_apic_irq_attr irq_attr;
 206
 207         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
 208
 209         /* MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to
 210          * IOAPIC RTE entries, so we just enable RTE for the device.
 211          */
 212         irq_attr.ioapic = mp_find_ioapic(dev->irq);
 213         irq_attr.ioapic_pin = dev->irq;
 214         irq_attr.trigger = 1; /* level */
 215         irq_attr.polarity = 1; /* active low */
 216         io_apic_set_pci_routing(&dev->dev, dev->irq, &irq_attr);
 217
 218         return 0;
 219 }
 220
 221 struct pci_ops pci_mrst_ops = {
 222         .read = pci_read,
 223         .write = pci_write,
 224 };
 225
 226 /**
 227  * pci_mrst_init - installs pci_mrst_ops
 228  *
 229  * Moorestown has an interesting PCI implementation (see above).
 230  * Called when the early platform detection installs it.
 231  */
 232 int __init pci_mrst_init(void)
 233 {
 234         printk(KERN_INFO "Moorestown platform detected, using MRST PCI ops\n");
 235         pci_mmcfg_late_init();
 236         pcibios_enable_irq = mrst_pci_irq_enable;
 237         pci_root_ops = pci_mrst_ops;
 238         /* Continue with standard init */
 239         return 1;
 240 }
 241
 242 /*
 243  * Langwell devices reside at fixed offsets, don't try to move them.
 244  */
 245 static void __devinit pci_fixed_bar_fixup(struct pci_dev *dev)
 246 {
 247         unsigned long offset;
 248         u32 size;
 249         int i;
 250
 251         /* Must have extended configuration space */
 252         if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
 253                 return;
 254
 255         /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 256         offset = fixed_bar_cap(dev->bus, dev->devfn);
 257         if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||
 258             PCI_DEVFN(2, 2) == dev->devfn)
 259                 return;
 260
 261         for (i = 0; i < PCI_ROM_RESOURCE; i++) {
 262                 pci_read_config_dword(dev, offset + 8 + (i * 4), &size);
 263                 dev->resource[i].end = dev->resource[i].start + size - 1;
 264                 dev->resource[i].flags |= IORESOURCE_PCI_FIXED;
 265         }
 266 }
 267 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup);