1/* 2 * Low-level PCI config space access for OLPC systems who lack the VSA 3 * PCI virtualization software. 4 * 5 * Copyright © 2006 Advanced Micro Devices, Inc. 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * The AMD Geode chipset (ie: GX2 processor, cs5536 I/O companion device) 13 * has some I/O functions (display, southbridge, sound, USB HCIs, etc) 14 * that more or less behave like PCI devices, but the hardware doesn't 15 * directly implement the PCI configuration space headers. AMD provides 16 * "VSA" (Virtual System Architecture) software that emulates PCI config 17 * space for these devices, by trapping I/O accesses to PCI config register 18 * (CF8/CFC) and running some code in System Management Mode interrupt state. 19 * On the OLPC platform, we don't want to use that VSA code because 20 * (a) it slows down suspend/resume, and (b) recompiling it requires special 21 * compilers that are hard to get. So instead of letting the complex VSA 22 * code simulate the PCI config registers for the on-chip devices, we 23 * just simulate them the easy way, by inserting the code into the 24 * pci_write_config and pci_read_config path. Most of the config registers 25 * are read-only anyway, so the bulk of the simulation is just table lookup. 26 */ 27 28#include <linux/pci.h> 29#include <linux/init.h> 30#include <asm/olpc.h> 31#include <asm/geode.h> 32#include <asm/pci_x86.h> 33 34/* 35 * In the tables below, the first two line (8 longwords) are the 36 * size masks that are used when the higher level PCI code determines 37 * the size of the region by writing ~0 to a base address register 38 * and reading back the result. 39 * 40 * The following lines are the values that are read during normal 41 * PCI config access cycles, i.e. not after just having written 42 * ~0 to a base address register. 43 */ 44 45static const uint32_t lxnb_hdr[] = { /* dev 1 function 0 - devfn = 8 */ 46 0x0, 0x0, 0x0, 0x0, 47 0x0, 0x0, 0x0, 0x0, 48 49 0x281022, 0x2200005, 0x6000021, 0x80f808, /* AMD Vendor ID */ 50 0x0, 0x0, 0x0, 0x0, /* No virtual registers, hence no BAR */ 51 0x0, 0x0, 0x0, 0x28100b, 52 0x0, 0x0, 0x0, 0x0, 53 0x0, 0x0, 0x0, 0x0, 54 0x0, 0x0, 0x0, 0x0, 55 0x0, 0x0, 0x0, 0x0, 56}; 57 58static const uint32_t gxnb_hdr[] = { /* dev 1 function 0 - devfn = 8 */ 59 0xfffffffd, 0x0, 0x0, 0x0, 60 0x0, 0x0, 0x0, 0x0, 61 62 0x28100b, 0x2200005, 0x6000021, 0x80f808, /* NSC Vendor ID */ 63 0xac1d, 0x0, 0x0, 0x0, /* I/O BAR - base of virtual registers */ 64 0x0, 0x0, 0x0, 0x28100b, 65 0x0, 0x0, 0x0, 0x0, 66 0x0, 0x0, 0x0, 0x0, 67 0x0, 0x0, 0x0, 0x0, 68 0x0, 0x0, 0x0, 0x0, 69}; 70 71static const uint32_t lxfb_hdr[] = { /* dev 1 function 1 - devfn = 9 */ 72 0xff000008, 0xffffc000, 0xffffc000, 0xffffc000, 73 0xffffc000, 0x0, 0x0, 0x0, 74 75 0x20811022, 0x2200003, 0x3000000, 0x0, /* AMD Vendor ID */ 76 0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */ 77 0xfe00c000, 0x0, 0x0, 0x30100b, /* VIP */ 78 0x0, 0x0, 0x0, 0x10e, /* INTA, IRQ14 for graphics accel */ 79 0x0, 0x0, 0x0, 0x0, 80 0x3d0, 0x3c0, 0xa0000, 0x0, /* VG IO, VG IO, EGA FB, MONO FB */ 81 0x0, 0x0, 0x0, 0x0, 82}; 83 84static const uint32_t gxfb_hdr[] = { /* dev 1 function 1 - devfn = 9 */ 85 0xff800008, 0xffffc000, 0xffffc000, 0xffffc000, 86 0x0, 0x0, 0x0, 0x0, 87 88 0x30100b, 0x2200003, 0x3000000, 0x0, /* NSC Vendor ID */ 89 0xfd000000, 0xfe000000, 0xfe004000, 0xfe008000, /* FB, GP, VG, DF */ 90 0x0, 0x0, 0x0, 0x30100b, 91 0x0, 0x0, 0x0, 0x0, 92 0x0, 0x0, 0x0, 0x0, 93 0x3d0, 0x3c0, 0xa0000, 0x0, /* VG IO, VG IO, EGA FB, MONO FB */ 94 0x0, 0x0, 0x0, 0x0, 95}; 96 97static const uint32_t aes_hdr[] = { /* dev 1 function 2 - devfn = 0xa */ 98 0xffffc000, 0x0, 0x0, 0x0, 99 0x0, 0x0, 0x0, 0x0, 100 101 0x20821022, 0x2a00006, 0x10100000, 0x8, /* NSC Vendor ID */ 102 0xfe010000, 0x0, 0x0, 0x0, /* AES registers */ 103 0x0, 0x0, 0x0, 0x20821022, 104 0x0, 0x0, 0x0, 0x0, 105 0x0, 0x0, 0x0, 0x0, 106 0x0, 0x0, 0x0, 0x0, 107 0x0, 0x0, 0x0, 0x0, 108}; 109 110 111static const uint32_t isa_hdr[] = { /* dev f function 0 - devfn = 78 */ 112 0xfffffff9, 0xffffff01, 0xffffffc1, 0xffffffe1, 113 0xffffff81, 0xffffffc1, 0x0, 0x0, 114 115 0x20901022, 0x2a00049, 0x6010003, 0x802000, 116 0x18b1, 0x1001, 0x1801, 0x1881, /* SMB-8 GPIO-256 MFGPT-64 IRQ-32 */ 117 0x1401, 0x1841, 0x0, 0x20901022, /* PMS-128 ACPI-64 */ 118 0x0, 0x0, 0x0, 0x0, 119 0x0, 0x0, 0x0, 0x0, 120 0x0, 0x0, 0x0, 0xaa5b, /* IRQ steering */ 121 0x0, 0x0, 0x0, 0x0, 122}; 123 124static const uint32_t ac97_hdr[] = { /* dev f function 3 - devfn = 7b */ 125 0xffffff81, 0x0, 0x0, 0x0, 126 0x0, 0x0, 0x0, 0x0, 127 128 0x20931022, 0x2a00041, 0x4010001, 0x0, 129 0x1481, 0x0, 0x0, 0x0, /* I/O BAR-128 */ 130 0x0, 0x0, 0x0, 0x20931022, 131 0x0, 0x0, 0x0, 0x205, /* IntB, IRQ5 */ 132 0x0, 0x0, 0x0, 0x0, 133 0x0, 0x0, 0x0, 0x0, 134 0x0, 0x0, 0x0, 0x0, 135}; 136 137static const uint32_t ohci_hdr[] = { /* dev f function 4 - devfn = 7c */ 138 0xfffff000, 0x0, 0x0, 0x0, 139 0x0, 0x0, 0x0, 0x0, 140 141 0x20941022, 0x2300006, 0xc031002, 0x0, 142 0xfe01a000, 0x0, 0x0, 0x0, /* MEMBAR-1000 */ 143 0x0, 0x0, 0x0, 0x20941022, 144 0x0, 0x40, 0x0, 0x40a, /* CapPtr INT-D, IRQA */ 145 0xc8020001, 0x0, 0x0, 0x0, /* Capabilities - 40 is R/O, 146 44 is mask 8103 (power control) */ 147 0x0, 0x0, 0x0, 0x0, 148 0x0, 0x0, 0x0, 0x0, 149}; 150 151static const uint32_t ehci_hdr[] = { /* dev f function 4 - devfn = 7d */ 152 0xfffff000, 0x0, 0x0, 0x0, 153 0x0, 0x0, 0x0, 0x0, 154 155 0x20951022, 0x2300006, 0xc032002, 0x0, 156 0xfe01b000, 0x0, 0x0, 0x0, /* MEMBAR-1000 */ 157 0x0, 0x0, 0x0, 0x20951022, 158 0x0, 0x40, 0x0, 0x40a, /* CapPtr INT-D, IRQA */ 159 0xc8020001, 0x0, 0x0, 0x0, /* Capabilities - 40 is R/O, 44 is 160 mask 8103 (power control) */ 161#if 0 162 0x1, 0x40080000, 0x0, 0x0, /* EECP - see EHCI spec section 2.1.7 */ 163#endif 164 0x01000001, 0x0, 0x0, 0x0, /* EECP - see EHCI spec section 2.1.7 */ 165 0x2020, 0x0, 0x0, 0x0, /* (EHCI page 8) 60 SBRN (R/O), 166 61 FLADJ (R/W), PORTWAKECAP */ 167}; 168 169static uint32_t ff_loc = ~0; 170static uint32_t zero_loc; 171static int bar_probing; /* Set after a write of ~0 to a BAR */ 172static int is_lx; 173 174#define NB_SLOT 0x1 /* Northbridge - GX chip - Device 1 */ 175#define SB_SLOT 0xf /* Southbridge - CS5536 chip - Device F */ 176 177static int is_simulated(unsigned int bus, unsigned int devfn) 178{ 179 return (!bus && ((PCI_SLOT(devfn) == NB_SLOT) || 180 (PCI_SLOT(devfn) == SB_SLOT))); 181} 182 183static uint32_t *hdr_addr(const uint32_t *hdr, int reg) 184{ 185 uint32_t addr; 186 187 /* 188 * This is a little bit tricky. The header maps consist of 189 * 0x20 bytes of size masks, followed by 0x70 bytes of header data. 190 * In the normal case, when not probing a BAR's size, we want 191 * to access the header data, so we add 0x20 to the reg offset, 192 * thus skipping the size mask area. 193 * In the BAR probing case, we want to access the size mask for 194 * the BAR, so we subtract 0x10 (the config header offset for 195 * BAR0), and don't skip the size mask area. 196 */ 197 198 addr = (uint32_t)hdr + reg + (bar_probing ? -0x10 : 0x20); 199 200 bar_probing = 0; 201 return (uint32_t *)addr; 202} 203 204static int pci_olpc_read(unsigned int seg, unsigned int bus, 205 unsigned int devfn, int reg, int len, uint32_t *value) 206{ 207 uint32_t *addr; 208 209 WARN_ON(seg); 210 211 /* Use the hardware mechanism for non-simulated devices */ 212 if (!is_simulated(bus, devfn)) 213 return pci_direct_conf1.read(seg, bus, devfn, reg, len, value); 214 215 /* 216 * No device has config registers past 0x70, so we save table space 217 * by not storing entries for the nonexistent registers 218 */ 219 if (reg >= 0x70) 220 addr = &zero_loc; 221 else { 222 switch (devfn) { 223 case 0x8: 224 addr = hdr_addr(is_lx ? lxnb_hdr : gxnb_hdr, reg); 225 break; 226 case 0x9: 227 addr = hdr_addr(is_lx ? lxfb_hdr : gxfb_hdr, reg); 228 break; 229 case 0xa: 230 addr = is_lx ? hdr_addr(aes_hdr, reg) : &ff_loc; 231 break; 232 case 0x78: 233 addr = hdr_addr(isa_hdr, reg); 234 break; 235 case 0x7b: 236 addr = hdr_addr(ac97_hdr, reg); 237 break; 238 case 0x7c: 239 addr = hdr_addr(ohci_hdr, reg); 240 break; 241 case 0x7d: 242 addr = hdr_addr(ehci_hdr, reg); 243 break; 244 default: 245 addr = &ff_loc; 246 break; 247 } 248 } 249 switch (len) { 250 case 1: 251 *value = *(uint8_t *)addr; 252 break; 253 case 2: 254 *value = *(uint16_t *)addr; 255 break; 256 case 4: 257 *value = *addr; 258 break; 259 default: 260 BUG(); 261 } 262 263 return 0; 264} 265 266static int pci_olpc_write(unsigned int seg, unsigned int bus, 267 unsigned int devfn, int reg, int len, uint32_t value) 268{ 269 WARN_ON(seg); 270 271 /* Use the hardware mechanism for non-simulated devices */ 272 if (!is_simulated(bus, devfn)) 273 return pci_direct_conf1.write(seg, bus, devfn, reg, len, value); 274 275 /* XXX we may want to extend this to simulate EHCI power management */ 276 277 /* 278 * Mostly we just discard writes, but if the write is a size probe 279 * (i.e. writing ~0 to a BAR), we remember it and arrange to return 280 * the appropriate size mask on the next read. This is cheating 281 * to some extent, because it depends on the fact that the next 282 * access after such a write will always be a read to the same BAR. 283 */ 284 285 if ((reg >= 0x10) && (reg < 0x2c)) { 286 /* write is to a BAR */ 287 if (value == ~0) 288 bar_probing = 1; 289 } else { 290 /* 291 * No warning on writes to ROM BAR, CMD, LATENCY_TIMER, 292 * CACHE_LINE_SIZE, or PM registers. 293 */ 294 if ((reg != PCI_ROM_ADDRESS) && (reg != PCI_COMMAND_MASTER) && 295 (reg != PCI_LATENCY_TIMER) && 296 (reg != PCI_CACHE_LINE_SIZE) && (reg != 0x44)) 297 printk(KERN_WARNING "OLPC PCI: Config write to devfn" 298 " %x reg %x value %x\n", devfn, reg, value); 299 } 300 301 return 0; 302} 303 304static const struct pci_raw_ops pci_olpc_conf = { 305 .read = pci_olpc_read, 306 .write = pci_olpc_write, 307}; 308 309int __init pci_olpc_init(void) 310{ 311 printk(KERN_INFO "PCI: Using configuration type OLPC XO-1\n"); 312 raw_pci_ops = &pci_olpc_conf; 313 is_lx = is_geode_lx(); 314 return 0; 315} 316