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 /* Quirks for the listed devices */ 39 #define PCI_DEVICE_ID_INTEL_MRFLD_MMC 0x1190 40 #define PCI_DEVICE_ID_INTEL_MRFLD_HSU 0x1191 41 42 /* Fixed BAR fields */ 43 #define PCIE_VNDR_CAP_ID_FIXED_BAR 0x00 /* Fixed BAR (TBD) */ 44 #define PCI_FIXED_BAR_0_SIZE 0x04 45 #define PCI_FIXED_BAR_1_SIZE 0x08 46 #define PCI_FIXED_BAR_2_SIZE 0x0c 47 #define PCI_FIXED_BAR_3_SIZE 0x10 48 #define PCI_FIXED_BAR_4_SIZE 0x14 49 #define PCI_FIXED_BAR_5_SIZE 0x1c 50 51 static int pci_soc_mode; 52 53 /** 54 * fixed_bar_cap - return the offset of the fixed BAR cap if found 55 * @bus: PCI bus 56 * @devfn: device in question 57 * 58 * Look for the fixed BAR cap on @bus and @devfn, returning its offset 59 * if found or 0 otherwise. 60 */ 61 static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn) 62 { 63 int pos; 64 u32 pcie_cap = 0, cap_data; 65 66 pos = PCIE_CAP_OFFSET; 67 68 if (!raw_pci_ext_ops) 69 return 0; 70 71 while (pos) { 72 if (raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 73 devfn, pos, 4, &pcie_cap)) 74 return 0; 75 76 if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 || 77 PCI_EXT_CAP_ID(pcie_cap) == 0xffff) 78 break; 79 80 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) { 81 raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 82 devfn, pos + 4, 4, &cap_data); 83 if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR) 84 return pos; 85 } 86 87 pos = PCI_EXT_CAP_NEXT(pcie_cap); 88 } 89 90 return 0; 91 } 92 93 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn, 94 int reg, int len, u32 val, int offset) 95 { 96 u32 size; 97 unsigned int domain, busnum; 98 int bar = (reg - PCI_BASE_ADDRESS_0) >> 2; 99 100 domain = pci_domain_nr(bus); 101 busnum = bus->number; 102 103 if (val == ~0 && len == 4) { 104 unsigned long decode; 105 106 raw_pci_ext_ops->read(domain, busnum, devfn, 107 offset + 8 + (bar * 4), 4, &size); 108 109 /* Turn the size into a decode pattern for the sizing code */ 110 if (size) { 111 decode = size - 1; 112 decode |= decode >> 1; 113 decode |= decode >> 2; 114 decode |= decode >> 4; 115 decode |= decode >> 8; 116 decode |= decode >> 16; 117 decode++; 118 decode = ~(decode - 1); 119 } else { 120 decode = 0; 121 } 122 123 /* 124 * If val is all ones, the core code is trying to size the reg, 125 * so update the mmconfig space with the real size. 126 * 127 * Note: this assumes the fixed size we got is a power of two. 128 */ 129 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4, 130 decode); 131 } 132 133 /* This is some other kind of BAR write, so just do it. */ 134 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val); 135 } 136 137 /** 138 * type1_access_ok - check whether to use type 1 139 * @bus: bus number 140 * @devfn: device & function in question 141 * 142 * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at 143 * all, the we can go ahead with any reads & writes. If it's on a Lincroft, 144 * but doesn't exist, avoid the access altogether to keep the chip from 145 * hanging. 146 */ 147 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg) 148 { 149 /* 150 * This is a workaround for A0 LNC bug where PCI status register does 151 * not have new CAP bit set. can not be written by SW either. 152 * 153 * PCI header type in real LNC indicates a single function device, this 154 * will prevent probing other devices under the same function in PCI 155 * shim. Therefore, use the header type in shim instead. 156 */ 157 if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE) 158 return false; 159 if (bus == 0 && (devfn == PCI_DEVFN(2, 0) 160 || devfn == PCI_DEVFN(0, 0) 161 || devfn == PCI_DEVFN(3, 0))) 162 return true; 163 return false; /* Langwell on others */ 164 } 165 166 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where, 167 int size, u32 *value) 168 { 169 if (type1_access_ok(bus->number, devfn, where)) 170 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number, 171 devfn, where, size, value); 172 return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 173 devfn, where, size, value); 174 } 175 176 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where, 177 int size, u32 value) 178 { 179 int offset; 180 181 /* 182 * On MRST, there is no PCI ROM BAR, this will cause a subsequent read 183 * to ROM BAR return 0 then being ignored. 184 */ 185 if (where == PCI_ROM_ADDRESS) 186 return 0; 187 188 /* 189 * Devices with fixed BARs need special handling: 190 * - BAR sizing code will save, write ~0, read size, restore 191 * - so writes to fixed BARs need special handling 192 * - other writes to fixed BAR devices should go through mmconfig 193 */ 194 offset = fixed_bar_cap(bus, devfn); 195 if (offset && 196 (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) { 197 return pci_device_update_fixed(bus, devfn, where, size, value, 198 offset); 199 } 200 201 /* 202 * On Moorestown update both real & mmconfig space 203 * Note: early Lincroft silicon can't handle type 1 accesses to 204 * non-existent devices, so just eat the write in that case. 205 */ 206 if (type1_access_ok(bus->number, devfn, where)) 207 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number, 208 devfn, where, size, value); 209 return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn, 210 where, size, value); 211 } 212 213 static int intel_mid_pci_irq_enable(struct pci_dev *dev) 214 { 215 struct irq_alloc_info info; 216 int polarity; 217 int ret; 218 u8 gsi; 219 220 if (dev->irq_managed && dev->irq > 0) 221 return 0; 222 223 ret = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi); 224 if (ret < 0) { 225 dev_warn(&dev->dev, "Failed to read interrupt line: %d\n", ret); 226 return ret; 227 } 228 229 switch (intel_mid_identify_cpu()) { 230 case INTEL_MID_CPU_CHIP_TANGIER: 231 polarity = IOAPIC_POL_HIGH; 232 233 /* Special treatment for IRQ0 */ 234 if (gsi == 0) { 235 /* 236 * Skip HS UART common registers device since it has 237 * IRQ0 assigned and not used by the kernel. 238 */ 239 if (dev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU) 240 return -EBUSY; 241 /* 242 * TNG has IRQ0 assigned to eMMC controller. But there 243 * are also other devices with bogus PCI configuration 244 * that have IRQ0 assigned. This check ensures that 245 * eMMC gets it. The rest of devices still could be 246 * enabled without interrupt line being allocated. 247 */ 248 if (dev->device != PCI_DEVICE_ID_INTEL_MRFLD_MMC) 249 return 0; 250 } 251 break; 252 default: 253 polarity = IOAPIC_POL_LOW; 254 break; 255 } 256 257 ioapic_set_alloc_attr(&info, dev_to_node(&dev->dev), 1, polarity); 258 259 /* 260 * MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to 261 * IOAPIC RTE entries, so we just enable RTE for the device. 262 */ 263 ret = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info); 264 if (ret < 0) 265 return ret; 266 267 dev->irq = ret; 268 dev->irq_managed = 1; 269 270 return 0; 271 } 272 273 static void intel_mid_pci_irq_disable(struct pci_dev *dev) 274 { 275 if (!mp_should_keep_irq(&dev->dev) && dev->irq_managed && 276 dev->irq > 0) { 277 mp_unmap_irq(dev->irq); 278 dev->irq_managed = 0; 279 } 280 } 281 282 static struct pci_ops intel_mid_pci_ops = { 283 .read = pci_read, 284 .write = pci_write, 285 }; 286 287 /** 288 * intel_mid_pci_init - installs intel_mid_pci_ops 289 * 290 * Moorestown has an interesting PCI implementation (see above). 291 * Called when the early platform detection installs it. 292 */ 293 int __init intel_mid_pci_init(void) 294 { 295 pr_info("Intel MID platform detected, using MID PCI ops\n"); 296 pci_mmcfg_late_init(); 297 pcibios_enable_irq = intel_mid_pci_irq_enable; 298 pcibios_disable_irq = intel_mid_pci_irq_disable; 299 pci_root_ops = intel_mid_pci_ops; 300 pci_soc_mode = 1; 301 /* Continue with standard init */ 302 return 1; 303 } 304 305 /* 306 * Langwell devices are not true PCI devices; they are not subject to 10 ms 307 * d3 to d0 delay required by PCI spec. 308 */ 309 static void pci_d3delay_fixup(struct pci_dev *dev) 310 { 311 /* 312 * PCI fixups are effectively decided compile time. If we have a dual 313 * SoC/non-SoC kernel we don't want to mangle d3 on non-SoC devices. 314 */ 315 if (!pci_soc_mode) 316 return; 317 /* 318 * True PCI devices in Lincroft should allow type 1 access, the rest 319 * are Langwell fake PCI devices. 320 */ 321 if (type1_access_ok(dev->bus->number, dev->devfn, PCI_DEVICE_ID)) 322 return; 323 dev->d3_delay = 0; 324 } 325 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup); 326 327 static void mid_power_off_one_device(struct pci_dev *dev) 328 { 329 u16 pmcsr; 330 331 /* 332 * Update current state first, otherwise PCI core enforces PCI_D0 in 333 * pci_set_power_state() for devices which status was PCI_UNKNOWN. 334 */ 335 pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); 336 dev->current_state = (pci_power_t __force)(pmcsr & PCI_PM_CTRL_STATE_MASK); 337 338 pci_set_power_state(dev, PCI_D3hot); 339 } 340 341 static void mid_power_off_devices(struct pci_dev *dev) 342 { 343 int id; 344 345 if (!pci_soc_mode) 346 return; 347 348 id = intel_mid_pwr_get_lss_id(dev); 349 if (id < 0) 350 return; 351 352 /* 353 * This sets only PMCSR bits. The actual power off will happen in 354 * arch/x86/platform/intel-mid/pwr.c. 355 */ 356 mid_power_off_one_device(dev); 357 } 358 359 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, mid_power_off_devices); 360 361 /* 362 * Langwell devices reside at fixed offsets, don't try to move them. 363 */ 364 static void pci_fixed_bar_fixup(struct pci_dev *dev) 365 { 366 unsigned long offset; 367 u32 size; 368 int i; 369 370 if (!pci_soc_mode) 371 return; 372 373 /* Must have extended configuration space */ 374 if (dev->cfg_size < PCIE_CAP_OFFSET + 4) 375 return; 376 377 /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */ 378 offset = fixed_bar_cap(dev->bus, dev->devfn); 379 if (!offset || PCI_DEVFN(2, 0) == dev->devfn || 380 PCI_DEVFN(2, 2) == dev->devfn) 381 return; 382 383 for (i = 0; i < PCI_ROM_RESOURCE; i++) { 384 pci_read_config_dword(dev, offset + 8 + (i * 4), &size); 385 dev->resource[i].end = dev->resource[i].start + size - 1; 386 dev->resource[i].flags |= IORESOURCE_PCI_FIXED; 387 } 388 } 389 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup); 390