1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Low-level PCI config space access for OLPC systems who lack the VSA 4 * PCI virtualization software. 5 * 6 * Copyright © 2006 Advanced Micro Devices, Inc. 7 * 8 * The AMD Geode chipset (ie: GX2 processor, cs5536 I/O companion device) 9 * has some I/O functions (display, southbridge, sound, USB HCIs, etc) 10 * that more or less behave like PCI devices, but the hardware doesn't 11 * directly implement the PCI configuration space headers. AMD provides 12 * "VSA" (Virtual System Architecture) software that emulates PCI config 13 * space for these devices, by trapping I/O accesses to PCI config register 14 * (CF8/CFC) and running some code in System Management Mode interrupt state. 15 * On the OLPC platform, we don't want to use that VSA code because 16 * (a) it slows down suspend/resume, and (b) recompiling it requires special 17 * compilers that are hard to get. So instead of letting the complex VSA 18 * code simulate the PCI config registers for the on-chip devices, we 19 * just simulate them the easy way, by inserting the code into the 20 * pci_write_config and pci_read_config path. Most of the config registers 21 * are read-only anyway, so the bulk of the simulation is just table lookup. 22 */ 23 24 #include <linux/pci.h> 25 #include <linux/init.h> 26 #include <asm/olpc.h> 27 #include <asm/geode.h> 28 #include <asm/pci_x86.h> 29 30 /* 31 * In the tables below, the first two line (8 longwords) are the 32 * size masks that are used when the higher level PCI code determines 33 * the size of the region by writing ~0 to a base address register 34 * and reading back the result. 35 * 36 * The following lines are the values that are read during normal 37 * PCI config access cycles, i.e. not after just having written 38 * ~0 to a base address register. 39 */ 40 41 static const uint32_t lxnb_hdr[] = { /* dev 1 function 0 - devfn = 8 */ 42 0x0, 0x0, 0x0, 0x0, 43 0x0, 0x0, 0x0, 0x0, 44 45 0x281022, 0x2200005, 0x6000021, 0x80f808, /* AMD Vendor ID */ 46 0x0, 0x0, 0x0, 0x0, /* No virtual registers, hence no BAR */ 47 0x0, 0x0, 0x0, 0x28100b, 48 0x0, 0x0, 0x0, 0x0, 49 0x0, 0x0, 0x0, 0x0, 50 0x0, 0x0, 0x0, 0x0, 51 0x0, 0x0, 0x0, 0x0, 52 }; 53 54 static const uint32_t gxnb_hdr[] = { /* dev 1 function 0 - devfn = 8 */ 55 0xfffffffd, 0x0, 0x0, 0x0, 56 0x0, 0x0, 0x0, 0x0, 57 58 0x28100b, 0x2200005, 0x6000021, 0x80f808, /* NSC Vendor ID */ 59 0xac1d, 0x0, 0x0, 0x0, /* I/O BAR - base of virtual registers */ 60 0x0, 0x0, 0x0, 0x28100b, 61 0x0, 0x0, 0x0, 0x0, 62 0x0, 0x0, 0x0, 0x0, 63 0x0, 0x0, 0x0, 0x0, 64 0x0, 0x0, 0x0, 0x0, 65 }; 66 67 static const uint32_t lxfb_hdr[] = { /* dev 1 function 1 - devfn = 9 */ 68 0xff000008, 0xffffc000, 0xffffc000, 0xffffc000, 69 0xffffc000, 0x0, 0x0, 0x0, 70 71 0x20811022, 0x2200003, 0x3000000, 0x0, /* AMD Vendor ID */ 72 0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */ 73 0xfe00c000, 0x0, 0x0, 0x30100b, /* VIP */ 74 0x0, 0x0, 0x0, 0x10e, /* INTA, IRQ14 for graphics accel */ 75 0x0, 0x0, 0x0, 0x0, 76 0x3d0, 0x3c0, 0xa0000, 0x0, /* VG IO, VG IO, EGA FB, MONO FB */ 77 0x0, 0x0, 0x0, 0x0, 78 }; 79 80 static const uint32_t gxfb_hdr[] = { /* dev 1 function 1 - devfn = 9 */ 81 0xff800008, 0xffffc000, 0xffffc000, 0xffffc000, 82 0x0, 0x0, 0x0, 0x0, 83 84 0x30100b, 0x2200003, 0x3000000, 0x0, /* NSC Vendor ID */ 85 0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */ 86 0x0, 0x0, 0x0, 0x30100b, 87 0x0, 0x0, 0x0, 0x0, 88 0x0, 0x0, 0x0, 0x0, 89 0x3d0, 0x3c0, 0xa0000, 0x0, /* VG IO, VG IO, EGA FB, MONO FB */ 90 0x0, 0x0, 0x0, 0x0, 91 }; 92 93 static const uint32_t aes_hdr[] = { /* dev 1 function 2 - devfn = 0xa */ 94 0xffffc000, 0x0, 0x0, 0x0, 95 0x0, 0x0, 0x0, 0x0, 96 97 0x20821022, 0x2a00006, 0x10100000, 0x8, /* NSC Vendor ID */ 98 0xfe010000, 0x0, 0x0, 0x0, /* AES registers */ 99 0x0, 0x0, 0x0, 0x20821022, 100 0x0, 0x0, 0x0, 0x0, 101 0x0, 0x0, 0x0, 0x0, 102 0x0, 0x0, 0x0, 0x0, 103 0x0, 0x0, 0x0, 0x0, 104 }; 105 106 107 static const uint32_t isa_hdr[] = { /* dev f function 0 - devfn = 78 */ 108 0xfffffff9, 0xffffff01, 0xffffffc1, 0xffffffe1, 109 0xffffff81, 0xffffffc1, 0x0, 0x0, 110 111 0x20901022, 0x2a00049, 0x6010003, 0x802000, 112 0x18b1, 0x1001, 0x1801, 0x1881, /* SMB-8 GPIO-256 MFGPT-64 IRQ-32 */ 113 0x1401, 0x1841, 0x0, 0x20901022, /* PMS-128 ACPI-64 */ 114 0x0, 0x0, 0x0, 0x0, 115 0x0, 0x0, 0x0, 0x0, 116 0x0, 0x0, 0x0, 0xaa5b, /* IRQ steering */ 117 0x0, 0x0, 0x0, 0x0, 118 }; 119 120 static const uint32_t ac97_hdr[] = { /* dev f function 3 - devfn = 7b */ 121 0xffffff81, 0x0, 0x0, 0x0, 122 0x0, 0x0, 0x0, 0x0, 123 124 0x20931022, 0x2a00041, 0x4010001, 0x0, 125 0x1481, 0x0, 0x0, 0x0, /* I/O BAR-128 */ 126 0x0, 0x0, 0x0, 0x20931022, 127 0x0, 0x0, 0x0, 0x205, /* IntB, IRQ5 */ 128 0x0, 0x0, 0x0, 0x0, 129 0x0, 0x0, 0x0, 0x0, 130 0x0, 0x0, 0x0, 0x0, 131 }; 132 133 static const uint32_t ohci_hdr[] = { /* dev f function 4 - devfn = 7c */ 134 0xfffff000, 0x0, 0x0, 0x0, 135 0x0, 0x0, 0x0, 0x0, 136 137 0x20941022, 0x2300006, 0xc031002, 0x0, 138 0xfe01a000, 0x0, 0x0, 0x0, /* MEMBAR-1000 */ 139 0x0, 0x0, 0x0, 0x20941022, 140 0x0, 0x40, 0x0, 0x40a, /* CapPtr INT-D, IRQA */ 141 0xc8020001, 0x0, 0x0, 0x0, /* Capabilities - 40 is R/O, 142 44 is mask 8103 (power control) */ 143 0x0, 0x0, 0x0, 0x0, 144 0x0, 0x0, 0x0, 0x0, 145 }; 146 147 static const uint32_t ehci_hdr[] = { /* dev f function 4 - devfn = 7d */ 148 0xfffff000, 0x0, 0x0, 0x0, 149 0x0, 0x0, 0x0, 0x0, 150 151 0x20951022, 0x2300006, 0xc032002, 0x0, 152 0xfe01b000, 0x0, 0x0, 0x0, /* MEMBAR-1000 */ 153 0x0, 0x0, 0x0, 0x20951022, 154 0x0, 0x40, 0x0, 0x40a, /* CapPtr INT-D, IRQA */ 155 0xc8020001, 0x0, 0x0, 0x0, /* Capabilities - 40 is R/O, 44 is 156 mask 8103 (power control) */ 157 0x01000001, 0x0, 0x0, 0x0, /* EECP - see EHCI spec section 2.1.7 */ 158 0x2020, 0x0, 0x0, 0x0, /* (EHCI page 8) 60 SBRN (R/O), 159 61 FLADJ (R/W), PORTWAKECAP */ 160 }; 161 162 static uint32_t ff_loc = ~0; 163 static uint32_t zero_loc; 164 static int bar_probing; /* Set after a write of ~0 to a BAR */ 165 static int is_lx; 166 167 #define NB_SLOT 0x1 /* Northbridge - GX chip - Device 1 */ 168 #define SB_SLOT 0xf /* Southbridge - CS5536 chip - Device F */ 169 170 static int is_simulated(unsigned int bus, unsigned int devfn) 171 { 172 return (!bus && ((PCI_SLOT(devfn) == NB_SLOT) || 173 (PCI_SLOT(devfn) == SB_SLOT))); 174 } 175 176 static uint32_t *hdr_addr(const uint32_t *hdr, int reg) 177 { 178 uint32_t addr; 179 180 /* 181 * This is a little bit tricky. The header maps consist of 182 * 0x20 bytes of size masks, followed by 0x70 bytes of header data. 183 * In the normal case, when not probing a BAR's size, we want 184 * to access the header data, so we add 0x20 to the reg offset, 185 * thus skipping the size mask area. 186 * In the BAR probing case, we want to access the size mask for 187 * the BAR, so we subtract 0x10 (the config header offset for 188 * BAR0), and don't skip the size mask area. 189 */ 190 191 addr = (uint32_t)hdr + reg + (bar_probing ? -0x10 : 0x20); 192 193 bar_probing = 0; 194 return (uint32_t *)addr; 195 } 196 197 static int pci_olpc_read(unsigned int seg, unsigned int bus, 198 unsigned int devfn, int reg, int len, uint32_t *value) 199 { 200 uint32_t *addr; 201 202 WARN_ON(seg); 203 204 /* Use the hardware mechanism for non-simulated devices */ 205 if (!is_simulated(bus, devfn)) 206 return pci_direct_conf1.read(seg, bus, devfn, reg, len, value); 207 208 /* 209 * No device has config registers past 0x70, so we save table space 210 * by not storing entries for the nonexistent registers 211 */ 212 if (reg >= 0x70) 213 addr = &zero_loc; 214 else { 215 switch (devfn) { 216 case 0x8: 217 addr = hdr_addr(is_lx ? lxnb_hdr : gxnb_hdr, reg); 218 break; 219 case 0x9: 220 addr = hdr_addr(is_lx ? lxfb_hdr : gxfb_hdr, reg); 221 break; 222 case 0xa: 223 addr = is_lx ? hdr_addr(aes_hdr, reg) : &ff_loc; 224 break; 225 case 0x78: 226 addr = hdr_addr(isa_hdr, reg); 227 break; 228 case 0x7b: 229 addr = hdr_addr(ac97_hdr, reg); 230 break; 231 case 0x7c: 232 addr = hdr_addr(ohci_hdr, reg); 233 break; 234 case 0x7d: 235 addr = hdr_addr(ehci_hdr, reg); 236 break; 237 default: 238 addr = &ff_loc; 239 break; 240 } 241 } 242 switch (len) { 243 case 1: 244 *value = *(uint8_t *)addr; 245 break; 246 case 2: 247 *value = *(uint16_t *)addr; 248 break; 249 case 4: 250 *value = *addr; 251 break; 252 default: 253 BUG(); 254 } 255 256 return 0; 257 } 258 259 static int pci_olpc_write(unsigned int seg, unsigned int bus, 260 unsigned int devfn, int reg, int len, uint32_t value) 261 { 262 WARN_ON(seg); 263 264 /* Use the hardware mechanism for non-simulated devices */ 265 if (!is_simulated(bus, devfn)) 266 return pci_direct_conf1.write(seg, bus, devfn, reg, len, value); 267 268 /* XXX we may want to extend this to simulate EHCI power management */ 269 270 /* 271 * Mostly we just discard writes, but if the write is a size probe 272 * (i.e. writing ~0 to a BAR), we remember it and arrange to return 273 * the appropriate size mask on the next read. This is cheating 274 * to some extent, because it depends on the fact that the next 275 * access after such a write will always be a read to the same BAR. 276 */ 277 278 if ((reg >= 0x10) && (reg < 0x2c)) { 279 /* write is to a BAR */ 280 if (value == ~0) 281 bar_probing = 1; 282 } else { 283 /* 284 * No warning on writes to ROM BAR, CMD, LATENCY_TIMER, 285 * CACHE_LINE_SIZE, or PM registers. 286 */ 287 if ((reg != PCI_ROM_ADDRESS) && (reg != PCI_COMMAND_MASTER) && 288 (reg != PCI_LATENCY_TIMER) && 289 (reg != PCI_CACHE_LINE_SIZE) && (reg != 0x44)) 290 printk(KERN_WARNING "OLPC PCI: Config write to devfn" 291 " %x reg %x value %x\n", devfn, reg, value); 292 } 293 294 return 0; 295 } 296 297 static const struct pci_raw_ops pci_olpc_conf = { 298 .read = pci_olpc_read, 299 .write = pci_olpc_write, 300 }; 301 302 int __init pci_olpc_init(void) 303 { 304 printk(KERN_INFO "PCI: Using configuration type OLPC XO-1\n"); 305 raw_pci_ops = &pci_olpc_conf; 306 is_lx = is_geode_lx(); 307 return 0; 308 } 309