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 (pcie_cap == 0xffffffff)
  70                         return 0;
  71
  72                 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) {
  73                         raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  74                                               devfn, pos + 4, 4, &cap_data);
  75                         if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR)
  76                                 return pos;
  77                 }
  78
  79                 pos = pcie_cap >> 20;
  80         }
  81
  82         return 0;
  83 }
  84
  85 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn,
  86                                    int reg, int len, u32 val, int offset)
  87 {
  88         u32 size;
  89         unsigned int domain, busnum;
  90         int bar = (reg - PCI_BASE_ADDRESS_0) >> 2;
  91
  92         domain = pci_domain_nr(bus);
  93         busnum = bus->number;
  94
  95         if (val == ~0 && len == 4) {
  96                 unsigned long decode;
  97
  98                 raw_pci_ext_ops->read(domain, busnum, devfn,
  99                                offset + 8 + (bar * 4), 4, &size);
 100
 101                 /* Turn the size into a decode pattern for the sizing code */
 102                 if (size) {
 103                         decode = size - 1;
 104                         decode |= decode >> 1;
 105                         decode |= decode >> 2;
 106                         decode |= decode >> 4;
 107                         decode |= decode >> 8;
 108                         decode |= decode >> 16;
 109                         decode++;
 110                         decode = ~(decode - 1);
 111                 } else {
 112                         decode = 0;
 113                 }
 114
 115                 /*
 116                  * If val is all ones, the core code is trying to size the reg,
 117                  * so update the mmconfig space with the real size.
 118                  *
 119                  * Note: this assumes the fixed size we got is a power of two.
 120                  */
 121                 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4,
 122                                        decode);
 123         }
 124
 125         /* This is some other kind of BAR write, so just do it. */
 126         return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val);
 127 }
 128
 129 /**
 130  * type1_access_ok - check whether to use type 1
 131  * @bus: bus number
 132  * @devfn: device & function in question
 133  *
 134  * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at
 135  * all, the we can go ahead with any reads & writes.  If it's on a Lincroft,
 136  * but doesn't exist, avoid the access altogether to keep the chip from
 137  * hanging.
 138  */
 139 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg)
 140 {
 141         /* This is a workaround for A0 LNC bug where PCI status register does
 142          * not have new CAP bit set. can not be written by SW either.
 143          *
 144          * PCI header type in real LNC indicates a single function device, this
 145          * will prevent probing other devices under the same function in PCI
 146          * shim. Therefore, use the header type in shim instead.
 147          */
 148         if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE)
 149                 return 0;
 150         if (bus == 0 && (devfn == PCI_DEVFN(2, 0) || devfn == PCI_DEVFN(0, 0)))
 151                 return 1;
 152         return 0; /* langwell on others */
 153 }
 154
 155 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 156                     int size, u32 *value)
 157 {
 158         if (type1_access_ok(bus->number, devfn, where))
 159                 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number,
 160                                         devfn, where, size, value);
 161         return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
 162                               devfn, where, size, value);
 163 }
 164
 165 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 166                      int size, u32 value)
 167 {
 168         int offset;
 169
 170         /* On MRST, there is no PCI ROM BAR, this will cause a subsequent read
 171          * to ROM BAR return 0 then being ignored.
 172          */
 173         if (where == PCI_ROM_ADDRESS)
 174                 return 0;
 175
 176         /*
 177          * Devices with fixed BARs need special handling:
 178          *   - BAR sizing code will save, write ~0, read size, restore
 179          *   - so writes to fixed BARs need special handling
 180          *   - other writes to fixed BAR devices should go through mmconfig
 181          */
 182         offset = fixed_bar_cap(bus, devfn);
 183         if (offset &&
 184             (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) {
 185                 return pci_device_update_fixed(bus, devfn, where, size, value,
 186                                                offset);
 187         }
 188
 189         /*
 190          * On Moorestown update both real & mmconfig space
 191          * Note: early Lincroft silicon can't handle type 1 accesses to
 192          *       non-existent devices, so just eat the write in that case.
 193          */
 194         if (type1_access_ok(bus->number, devfn, where))
 195                 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number,
 196                                               devfn, where, size, value);
 197         return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn,
 198                                where, size, value);
 199 }
 200
 201 static int mrst_pci_irq_enable(struct pci_dev *dev)
 202 {
 203         u8 pin;
 204         struct io_apic_irq_attr irq_attr;
 205
 206         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
 207
 208         /* MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to
 209          * IOAPIC RTE entries, so we just enable RTE for the device.
 210          */
 211         irq_attr.ioapic = mp_find_ioapic(dev->irq);
 212         irq_attr.ioapic_pin = dev->irq;
 213         irq_attr.trigger = 1; /* level */
 214         irq_attr.polarity = 1; /* active low */
 215         io_apic_set_pci_routing(&dev->dev, dev->irq, &irq_attr);
 216
 217         return 0;
 218 }
 219
 220 struct pci_ops pci_mrst_ops = {
 221         .read = pci_read,
 222         .write = pci_write,
 223 };
 224
 225 /**
 226  * pci_mrst_init - installs pci_mrst_ops
 227  *
 228  * Moorestown has an interesting PCI implementation (see above).
 229  * Called when the early platform detection installs it.
 230  */
 231 int __init pci_mrst_init(void)
 232 {
 233         printk(KERN_INFO "Moorestown platform detected, using MRST PCI ops\n");
 234         pci_mmcfg_late_init();
 235         pcibios_enable_irq = mrst_pci_irq_enable;
 236         pci_root_ops = pci_mrst_ops;
 237         /* Continue with standard init */
 238         return 1;
 239 }
 240
 241 /*
 242  * Langwell devices reside at fixed offsets, don't try to move them.
 243  */
 244 static void __devinit pci_fixed_bar_fixup(struct pci_dev *dev)
 245 {
 246         unsigned long offset;
 247         u32 size;
 248         int i;
 249
 250         /* Must have extended configuration space */
 251         if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
 252                 return;
 253
 254         /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 255         offset = fixed_bar_cap(dev->bus, dev->devfn);
 256         if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||
 257             PCI_DEVFN(2, 2) == dev->devfn)
 258                 return;
 259
 260         for (i = 0; i < PCI_ROM_RESOURCE; i++) {
 261                 pci_read_config_dword(dev, offset + 8 + (i * 4), &size);
 262                 dev->resource[i].end = dev->resource[i].start + size - 1;
 263                 dev->resource[i].flags |= IORESOURCE_PCI_FIXED;
 264         }
 265 }
 266 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup);