1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Intel MID PCI support 4 * Copyright (c) 2008 Intel Corporation 5 * Jesse Barnes <jesse.barnes@intel.com> 6 * 7 * Moorestown has an interesting PCI implementation: 8 * - configuration space is memory mapped (as defined by MCFG) 9 * - Lincroft devices also have a real, type 1 configuration space 10 * - Early Lincroft silicon has a type 1 access bug that will cause 11 * a hang if non-existent devices are accessed 12 * - some devices have the "fixed BAR" capability, which means 13 * they can't be relocated or modified; check for that during 14 * BAR sizing 15 * 16 * So, we use the MCFG space for all reads and writes, but also send 17 * Lincroft writes to type 1 space. But only read/write if the device 18 * actually exists, otherwise return all 1s for reads and bit bucket 19 * the writes. 20 */ 21 22 #include <linux/sched.h> 23 #include <linux/pci.h> 24 #include <linux/ioport.h> 25 #include <linux/init.h> 26 #include <linux/dmi.h> 27 #include <linux/acpi.h> 28 #include <linux/io.h> 29 #include <linux/smp.h> 30 31 #include <asm/segment.h> 32 #include <asm/pci_x86.h> 33 #include <asm/hw_irq.h> 34 #include <asm/io_apic.h> 35 #include <asm/intel-mid.h> 36 #include <asm/acpi.h> 37 38 #define PCIE_CAP_OFFSET 0x100 39 40 /* Quirks for the listed devices */ 41 #define PCI_DEVICE_ID_INTEL_MRFLD_MMC 0x1190 42 #define PCI_DEVICE_ID_INTEL_MRFLD_HSU 0x1191 43 44 /* Fixed BAR fields */ 45 #define PCIE_VNDR_CAP_ID_FIXED_BAR 0x00 /* Fixed BAR (TBD) */ 46 #define PCI_FIXED_BAR_0_SIZE 0x04 47 #define PCI_FIXED_BAR_1_SIZE 0x08 48 #define PCI_FIXED_BAR_2_SIZE 0x0c 49 #define PCI_FIXED_BAR_3_SIZE 0x10 50 #define PCI_FIXED_BAR_4_SIZE 0x14 51 #define PCI_FIXED_BAR_5_SIZE 0x1c 52 53 static int pci_soc_mode; 54 55 /** 56 * fixed_bar_cap - return the offset of the fixed BAR cap if found 57 * @bus: PCI bus 58 * @devfn: device in question 59 * 60 * Look for the fixed BAR cap on @bus and @devfn, returning its offset 61 * if found or 0 otherwise. 62 */ 63 static int fixed_bar_cap(struct pci_bus *bus, unsigned int devfn) 64 { 65 int pos; 66 u32 pcie_cap = 0, cap_data; 67 68 pos = PCIE_CAP_OFFSET; 69 70 if (!raw_pci_ext_ops) 71 return 0; 72 73 while (pos) { 74 if (raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 75 devfn, pos, 4, &pcie_cap)) 76 return 0; 77 78 if (PCI_EXT_CAP_ID(pcie_cap) == 0x0000 || 79 PCI_EXT_CAP_ID(pcie_cap) == 0xffff) 80 break; 81 82 if (PCI_EXT_CAP_ID(pcie_cap) == PCI_EXT_CAP_ID_VNDR) { 83 raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 84 devfn, pos + 4, 4, &cap_data); 85 if ((cap_data & 0xffff) == PCIE_VNDR_CAP_ID_FIXED_BAR) 86 return pos; 87 } 88 89 pos = PCI_EXT_CAP_NEXT(pcie_cap); 90 } 91 92 return 0; 93 } 94 95 static int pci_device_update_fixed(struct pci_bus *bus, unsigned int devfn, 96 int reg, int len, u32 val, int offset) 97 { 98 u32 size; 99 unsigned int domain, busnum; 100 int bar = (reg - PCI_BASE_ADDRESS_0) >> 2; 101 102 domain = pci_domain_nr(bus); 103 busnum = bus->number; 104 105 if (val == ~0 && len == 4) { 106 unsigned long decode; 107 108 raw_pci_ext_ops->read(domain, busnum, devfn, 109 offset + 8 + (bar * 4), 4, &size); 110 111 /* Turn the size into a decode pattern for the sizing code */ 112 if (size) { 113 decode = size - 1; 114 decode |= decode >> 1; 115 decode |= decode >> 2; 116 decode |= decode >> 4; 117 decode |= decode >> 8; 118 decode |= decode >> 16; 119 decode++; 120 decode = ~(decode - 1); 121 } else { 122 decode = 0; 123 } 124 125 /* 126 * If val is all ones, the core code is trying to size the reg, 127 * so update the mmconfig space with the real size. 128 * 129 * Note: this assumes the fixed size we got is a power of two. 130 */ 131 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, 4, 132 decode); 133 } 134 135 /* This is some other kind of BAR write, so just do it. */ 136 return raw_pci_ext_ops->write(domain, busnum, devfn, reg, len, val); 137 } 138 139 /** 140 * type1_access_ok - check whether to use type 1 141 * @bus: bus number 142 * @devfn: device & function in question 143 * 144 * If the bus is on a Lincroft chip and it exists, or is not on a Lincroft at 145 * all, the we can go ahead with any reads & writes. If it's on a Lincroft, 146 * but doesn't exist, avoid the access altogether to keep the chip from 147 * hanging. 148 */ 149 static bool type1_access_ok(unsigned int bus, unsigned int devfn, int reg) 150 { 151 /* 152 * This is a workaround for A0 LNC bug where PCI status register does 153 * not have new CAP bit set. can not be written by SW either. 154 * 155 * PCI header type in real LNC indicates a single function device, this 156 * will prevent probing other devices under the same function in PCI 157 * shim. Therefore, use the header type in shim instead. 158 */ 159 if (reg >= 0x100 || reg == PCI_STATUS || reg == PCI_HEADER_TYPE) 160 return false; 161 if (bus == 0 && (devfn == PCI_DEVFN(2, 0) 162 || devfn == PCI_DEVFN(0, 0) 163 || devfn == PCI_DEVFN(3, 0))) 164 return true; 165 return false; /* Langwell on others */ 166 } 167 168 static int pci_read(struct pci_bus *bus, unsigned int devfn, int where, 169 int size, u32 *value) 170 { 171 if (type1_access_ok(bus->number, devfn, where)) 172 return pci_direct_conf1.read(pci_domain_nr(bus), bus->number, 173 devfn, where, size, value); 174 return raw_pci_ext_ops->read(pci_domain_nr(bus), bus->number, 175 devfn, where, size, value); 176 } 177 178 static int pci_write(struct pci_bus *bus, unsigned int devfn, int where, 179 int size, u32 value) 180 { 181 int offset; 182 183 /* 184 * On MRST, there is no PCI ROM BAR, this will cause a subsequent read 185 * to ROM BAR return 0 then being ignored. 186 */ 187 if (where == PCI_ROM_ADDRESS) 188 return 0; 189 190 /* 191 * Devices with fixed BARs need special handling: 192 * - BAR sizing code will save, write ~0, read size, restore 193 * - so writes to fixed BARs need special handling 194 * - other writes to fixed BAR devices should go through mmconfig 195 */ 196 offset = fixed_bar_cap(bus, devfn); 197 if (offset && 198 (where >= PCI_BASE_ADDRESS_0 && where <= PCI_BASE_ADDRESS_5)) { 199 return pci_device_update_fixed(bus, devfn, where, size, value, 200 offset); 201 } 202 203 /* 204 * On Moorestown update both real & mmconfig space 205 * Note: early Lincroft silicon can't handle type 1 accesses to 206 * non-existent devices, so just eat the write in that case. 207 */ 208 if (type1_access_ok(bus->number, devfn, where)) 209 return pci_direct_conf1.write(pci_domain_nr(bus), bus->number, 210 devfn, where, size, value); 211 return raw_pci_ext_ops->write(pci_domain_nr(bus), bus->number, devfn, 212 where, size, value); 213 } 214 215 static int intel_mid_pci_irq_enable(struct pci_dev *dev) 216 { 217 struct irq_alloc_info info; 218 int polarity; 219 int ret; 220 u8 gsi; 221 222 if (dev->irq_managed && dev->irq > 0) 223 return 0; 224 225 ret = pci_read_config_byte(dev, PCI_INTERRUPT_LINE, &gsi); 226 if (ret < 0) { 227 dev_warn(&dev->dev, "Failed to read interrupt line: %d\n", ret); 228 return ret; 229 } 230 231 switch (intel_mid_identify_cpu()) { 232 case INTEL_MID_CPU_CHIP_TANGIER: 233 polarity = IOAPIC_POL_HIGH; 234 235 /* Special treatment for IRQ0 */ 236 if (gsi == 0) { 237 /* 238 * Skip HS UART common registers device since it has 239 * IRQ0 assigned and not used by the kernel. 240 */ 241 if (dev->device == PCI_DEVICE_ID_INTEL_MRFLD_HSU) 242 return -EBUSY; 243 /* 244 * TNG has IRQ0 assigned to eMMC controller. But there 245 * are also other devices with bogus PCI configuration 246 * that have IRQ0 assigned. This check ensures that 247 * eMMC gets it. The rest of devices still could be 248 * enabled without interrupt line being allocated. 249 */ 250 if (dev->device != PCI_DEVICE_ID_INTEL_MRFLD_MMC) 251 return 0; 252 } 253 break; 254 default: 255 polarity = IOAPIC_POL_LOW; 256 break; 257 } 258 259 ioapic_set_alloc_attr(&info, dev_to_node(&dev->dev), 1, polarity); 260 261 /* 262 * MRST only have IOAPIC, the PCI irq lines are 1:1 mapped to 263 * IOAPIC RTE entries, so we just enable RTE for the device. 264 */ 265 ret = mp_map_gsi_to_irq(gsi, IOAPIC_MAP_ALLOC, &info); 266 if (ret < 0) 267 return ret; 268 269 dev->irq = ret; 270 dev->irq_managed = 1; 271 272 return 0; 273 } 274 275 static void intel_mid_pci_irq_disable(struct pci_dev *dev) 276 { 277 if (!mp_should_keep_irq(&dev->dev) && dev->irq_managed && 278 dev->irq > 0) { 279 mp_unmap_irq(dev->irq); 280 dev->irq_managed = 0; 281 } 282 } 283 284 static const struct pci_ops intel_mid_pci_ops __initconst = { 285 .read = pci_read, 286 .write = pci_write, 287 }; 288 289 /** 290 * intel_mid_pci_init - installs intel_mid_pci_ops 291 * 292 * Moorestown has an interesting PCI implementation (see above). 293 * Called when the early platform detection installs it. 294 */ 295 int __init intel_mid_pci_init(void) 296 { 297 pr_info("Intel MID platform detected, using MID PCI ops\n"); 298 pci_mmcfg_late_init(); 299 pcibios_enable_irq = intel_mid_pci_irq_enable; 300 pcibios_disable_irq = intel_mid_pci_irq_disable; 301 pci_root_ops = intel_mid_pci_ops; 302 pci_soc_mode = 1; 303 /* Continue with standard init */ 304 acpi_noirq_set(); 305 return 1; 306 } 307 308 /* 309 * Langwell devices are not true PCI devices; they are not subject to 10 ms 310 * d3 to d0 delay required by PCI spec. 311 */ 312 static void pci_d3delay_fixup(struct pci_dev *dev) 313 { 314 /* 315 * PCI fixups are effectively decided compile time. If we have a dual 316 * SoC/non-SoC kernel we don't want to mangle d3 on non-SoC devices. 317 */ 318 if (!pci_soc_mode) 319 return; 320 /* 321 * True PCI devices in Lincroft should allow type 1 access, the rest 322 * are Langwell fake PCI devices. 323 */ 324 if (type1_access_ok(dev->bus->number, dev->devfn, PCI_DEVICE_ID)) 325 return; 326 dev->d3hot_delay = 0; 327 } 328 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_d3delay_fixup); 329 330 static void mid_power_off_one_device(struct pci_dev *dev) 331 { 332 u16 pmcsr; 333 334 /* 335 * Update current state first, otherwise PCI core enforces PCI_D0 in 336 * pci_set_power_state() for devices which status was PCI_UNKNOWN. 337 */ 338 pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); 339 dev->current_state = (pci_power_t __force)(pmcsr & PCI_PM_CTRL_STATE_MASK); 340 341 pci_set_power_state(dev, PCI_D3hot); 342 } 343 344 static void mid_power_off_devices(struct pci_dev *dev) 345 { 346 int id; 347 348 if (!pci_soc_mode) 349 return; 350 351 id = intel_mid_pwr_get_lss_id(dev); 352 if (id < 0) 353 return; 354 355 /* 356 * This sets only PMCSR bits. The actual power off will happen in 357 * arch/x86/platform/intel-mid/pwr.c. 358 */ 359 mid_power_off_one_device(dev); 360 } 361 362 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, mid_power_off_devices); 363 364 /* 365 * Langwell devices reside at fixed offsets, don't try to move them. 366 */ 367 static void pci_fixed_bar_fixup(struct pci_dev *dev) 368 { 369 unsigned long offset; 370 u32 size; 371 int i; 372 373 if (!pci_soc_mode) 374 return; 375 376 /* Must have extended configuration space */ 377 if (dev->cfg_size < PCIE_CAP_OFFSET + 4) 378 return; 379 380 /* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */ 381 offset = fixed_bar_cap(dev->bus, dev->devfn); 382 if (!offset || PCI_DEVFN(2, 0) == dev->devfn || 383 PCI_DEVFN(2, 2) == dev->devfn) 384 return; 385 386 for (i = 0; i < PCI_STD_NUM_BARS; i++) { 387 pci_read_config_dword(dev, offset + 8 + (i * 4), &size); 388 dev->resource[i].end = dev->resource[i].start + size - 1; 389 dev->resource[i].flags |= IORESOURCE_PCI_FIXED; 390 } 391 } 392 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_ANY_ID, pci_fixed_bar_fixup); 393