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 #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
  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 static int pci_soc_mode;
  47
  48 /**
  49  * fixed_bar_cap - return the offset of the fixed BAR cap if found
  50  * @bus: PCI bus
  51  * @devfn: device in question
  52  *
  53  * Look for the fixed BAR cap on @bus and @devfn, returning its offset
  54  * if found or 0 otherwise.
  55  */
  56 static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn)
  57 {
  58         int pos;
  59         u32 pcie_cap = 0, cap_data;
  60
  61         pos = PCIE_CAP_OFFSET;
  62
  63         if (!raw_pci_ext_ops)
  64                 return 0;
  65
  66         while (pos) {
  67                 if (raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  68                                           devfn, pos, 4, &pcie_cap))
  69                         return 0;
  70
  71                 if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 ||
  72                         PCI_EXT_CAP_ID(pcie_cap) == 0xffff)
  73                         break;
  74
  75                 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) {
  76                         raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
  77                                               devfn, pos + 4, 4, &cap_data);
  78                         if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR)
  79                                 return pos;
  80                 }
  81
  82                 pos = PCI_EXT_CAP_NEXT(pcie_cap);
  83         }
  84
  85         return 0;
  86 }
  87
  88 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn,
  89                                    int reg, int len, u32 val, int offset)
  90 {
  91         u32 size;
  92         unsigned int domain, busnum;
  93         int bar = (reg - PCI_BASE_ADDRESS_0) >> 2;
  94
  95         domain = pci_domain_nr(bus);
  96         busnum = bus->number;
  97
  98         if (val == ~0 && len == 4) {
  99                 unsigned long decode;
 100
 101                 raw_pci_ext_ops->read(domain, busnum, devfn,
 102                                offset + 8 + (bar * 4), 4, &size);
 103
 104                 /* Turn the size into a decode pattern for the sizing code */
 105                 if (size) {
 106                         decode = size - 1;
 107                         decode |= decode >> 1;
 108                         decode |= decode >> 2;
 109                         decode |= decode >> 4;
 110                         decode |= decode >> 8;
 111                         decode |= decode >> 16;
 112                         decode++;
 113                         decode = ~(decode - 1);
 114                 } else {
 115                         decode = 0;
 116                 }
 117
 118                 /*
 119                  * If val is all ones, the core code is trying to size the reg,
 120                  * so update the mmconfig space with the real size.
 121                  *
 122                  * Note: this assumes the fixed size we got is a power of two.
 123                  */
 124                 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4,
 125                                        decode);
 126         }
 127
 128         /* This is some other kind of BAR write, so just do it. */
 129         return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val);
 130 }
 131
 132 /**
 133  * type1_access_ok - check whether to use type 1
 134  * @bus: bus number
 135  * @devfn: device & function in question
 136  *
 137  * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at
 138  * all, the we can go ahead with any reads & writes.  If it's on a Lincroft,
 139  * but doesn't exist, avoid the access altogether to keep the chip from
 140  * hanging.
 141  */
 142 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg)
 143 {
 144         /*
 145          * This is a workaround for A0 LNC bug where PCI status register does
 146          * not have new CAP bit set. can not be written by SW either.
 147          *
 148          * PCI header type in real LNC indicates a single function device, this
 149          * will prevent probing other devices under the same function in PCI
 150          * shim. Therefore, use the header type in shim instead.
 151          */
 152         if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE)
 153                 return 0;
 154         if (bus == 0 && (devfn == PCI_DEVFN(2, 0)
 155                                 || devfn == PCI_DEVFN(0, 0)
 156                                 || devfn == PCI_DEVFN(3, 0)))
 157                 return 1;
 158         return 0; /* Langwell on others */
 159 }
 160
 161 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where,
 162                     int size, u32 *value)
 163 {
 164         if (type1_access_ok(bus->number, devfn, where))
 165                 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number,
 166                                         devfn, where, size, value);
 167         return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number,
 168                               devfn, where, size, value);
 169 }
 170
 171 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where,
 172                      int size, u32 value)
 173 {
 174         int offset;
 175
 176         /*
 177          * On MRST, there is no PCI ROM BAR, this will cause a subsequent read
 178          * to ROM BAR return 0 then being ignored.
 179          */
 180         if (where == PCI_ROM_ADDRESS)
 181                 return 0;
 182
 183         /*
 184          * Devices with fixed BARs need special handling:
 185          *   - BAR sizing code will save, write ~0, read size, restore
 186          *   - so writes to fixed BARs need special handling
 187          *   - other writes to fixed BAR devices should go through mmconfig
 188          */
 189         offset = fixed_bar_cap(bus, devfn);
 190         if (offset &&
 191             (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) {
 192                 return pci_device_update_fixed(bus, devfn, where, size, value,
 193                                                offset);
 194         }
 195
 196         /*
 197          * On Moorestown update both real & mmconfig space
 198          * Note: early Lincroft silicon can't handle type 1 accesses to
 199          *       non-existent devices, so just eat the write in that case.
 200          */
 201         if (type1_access_ok(bus->number, devfn, where))
 202                 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number,
 203                                               devfn, where, size, value);
 204         return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn,
 205                                where, size, value);
 206 }
 207
 208 static int mrst_pci_irq_enable(struct pci_dev *dev)
 209 {
 210         u8 pin;
 211         struct io_apic_irq_attr irq_attr;
 212
 213         pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
 214
 215         /*
 216          * MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to
 217          * IOAPIC RTE entries, so we just enable RTE for the device.
 218          */
 219         irq_attr.ioapic = mp_find_ioapic(dev->irq);
 220         irq_attr.ioapic_pin = dev->irq;
 221         irq_attr.trigger = 1; /* level */
 222         irq_attr.polarity = 1; /* active low */
 223         io_apic_set_pci_routing(&dev->dev, dev->irq, &irq_attr);
 224
 225         return 0;
 226 }
 227
 228 struct pci_ops pci_mrst_ops = {
 229         .read = pci_read,
 230         .write = pci_write,
 231 };
 232
 233 /**
 234  * pci_mrst_init - installs pci_mrst_ops
 235  *
 236  * Moorestown has an interesting PCI implementation (see above).
 237  * Called when the early platform detection installs it.
 238  */
 239 int __init pci_mrst_init(void)
 240 {
 241         pr_info("Intel MID platform detected, using MID PCI ops\n");
 242         pci_mmcfg_late_init();
 243         pcibios_enable_irq = mrst_pci_irq_enable;
 244         pci_root_ops = pci_mrst_ops;
 245         pci_soc_mode = 1;
 246         /* Continue with standard init */
 247         return 1;
 248 }
 249
 250 /*
 251  * Langwell devices are not true PCI devices; they are not subject to 10 ms
 252  * d3 to d0 delay required by PCI spec.
 253  */
 254 static void pci_d3delay_fixup(struct pci_dev *dev)
 255 {
 256         /*
 257          * PCI fixups are effectively decided compile time. If we have a dual
 258          * SoC/non-SoC kernel we don't want to mangle d3 on non-SoC devices.
 259          */
 260         if (!pci_soc_mode)
 261                 return;
 262         /*
 263          * True PCI devices in Lincroft should allow type 1 access, the rest
 264          * are Langwell fake PCI devices.
 265          */
 266         if (type1_access_ok(dev->bus->number, dev->devfn, PCI_DEVICE_ID))
 267                 return;
 268         dev->d3_delay = 0;
 269 }
 270 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup);
 271
 272 static void mrst_power_off_unused_dev(struct pci_dev *dev)
 273 {
 274         pci_set_power_state(dev, PCI_D3hot);
 275 }
 276 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0801, mrst_power_off_unused_dev);
 277 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0809, mrst_power_off_unused_dev);
 278 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x080C, mrst_power_off_unused_dev);
 279 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0812, mrst_power_off_unused_dev);
 280 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, 0x0815, mrst_power_off_unused_dev);
 281
 282 /*
 283  * Langwell devices reside at fixed offsets, don't try to move them.
 284  */
 285 static void pci_fixed_bar_fixup(struct pci_dev *dev)
 286 {
 287         unsigned long offset;
 288         u32 size;
 289         int i;
 290
 291         if (!pci_soc_mode)
 292                 return;
 293
 294         /* Must have extended configuration space */
 295         if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
 296                 return;
 297
 298         /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 299         offset = fixed_bar_cap(dev->bus, dev->devfn);
 300         if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||
 301             PCI_DEVFN(2, 2) == dev->devfn)
 302                 return;
 303
 304         for (i = 0; i < PCI_ROM_RESOURCE; i++) {
 305                 pci_read_config_dword(dev, offset + 8 + (i * 4), &size);
 306                 dev->resource[i].end = dev->resource[i].start + size - 1;
 307                 dev->resource[i].flags |= IORESOURCE_PCI_FIXED;
 308         }
 309 }
 310 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup);