arch/ppc/syslib/qspan_pci.c

   1 /*
   2  * QSpan pci routines.
   3  * Most 8xx boards use the QSpan PCI bridge.  The config address register
   4  * is located 0x500 from the base of the bridge control/status registers.
   5  * The data register is located at 0x504.
   6  * This is a two step operation.  First, the address register is written,
   7  * then the data register is read/written as required.
   8  * I don't know what to do about interrupts (yet).
   9  *
  10  * The RPX Classic implementation shares a chip select for normal
  11  * PCI access and QSpan control register addresses.  The selection is
  12  * further selected by a bit setting in a board control register.
  13  * Although it should happen, we disable interrupts during this operation
  14  * to make sure some driver doesn't accidentally access the PCI while
  15  * we have switched the chip select.
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/pci.h>
  20 #include <linux/delay.h>
  21 #include <linux/string.h>
  22 #include <linux/init.h>
  23
  24 #include <asm/io.h>
  25 #include <asm/mpc8xx.h>
  26 #include <asm/system.h>
  27 #include <asm/machdep.h>
  28 #include <asm/pci-bridge.h>
  29
  30
  31 /*
  32  * This blows......
  33  * When reading the configuration space, if something does not respond
  34  * the bus times out and we get a machine check interrupt.  So, the
  35  * good ol' exception tables come to mind to trap it and return some
  36  * value.
  37  *
  38  * On an error we just return a -1, since that is what the caller wants
  39  * returned if nothing is present.  I copied this from __get_user_asm,
  40  * with the only difference of returning -1 instead of EFAULT.
  41  * There is an associated hack in the machine check trap code.
  42  *
  43  * The QSPAN is also a big endian device, that is it makes the PCI
  44  * look big endian to us.  This presents a problem for the Linux PCI
  45  * functions, which assume little endian.  For example, we see the
  46  * first 32-bit word like this:
  47  *      ------------------------
  48  *      | Device ID | Vendor ID |
  49  *      ------------------------
  50  * If we read/write as a double word, that's OK.  But in our world,
  51  * when read as a word, device ID is at location 0, not location 2 as
  52  * the little endian PCI would believe.  We have to switch bits in
  53  * the PCI addresses given to us to get the data to/from the correct
  54  * byte lanes.
  55  *
  56  * The QSPAN only supports 4 bits of "slot" in the dev_fn instead of 5.
  57  * It always forces the MS bit to zero.  Therefore, dev_fn values
  58  * greater than 128 are returned as "no device found" errors.
  59  *
  60  * The QSPAN can only perform long word (32-bit) configuration cycles.
  61  * The "offset" must have the two LS bits set to zero.  Read operations
  62  * require we read the entire word and then sort out what should be
  63  * returned.  Write operations other than long word require that we
  64  * read the long word, update the proper word or byte, then write the
  65  * entire long word back.
  66  *
  67  * PCI Bridge hack.  We assume (correctly) that bus 0 is the primary
  68  * PCI bus from the QSPAN.  If we are called with a bus number other
  69  * than zero, we create a Type 1 configuration access that a downstream
  70  * PCI bridge will interpret.
  71  */
  72
  73 #define __get_qspan_pci_config(x, addr, op)             \
  74         __asm__ __volatile__(                           \
  75                 "1:     "op" %0,0(%1)\n"                \
  76                 "       eieio\n"                        \
  77                 "2:\n"                                  \
  78                 ".section .fixup,\"ax\"\n"              \
  79                 "3:     li %0,-1\n"                     \
  80                 "       b 2b\n"                         \
  81                 ".section __ex_table,\"a\"\n"           \
  82                 "       .align 2\n"                     \
  83                 "       .long 1b,3b\n"                  \
  84                 ".text"                                 \
  85                 : "=r"(x) : "r"(addr) : " %0")
  86
  87 #define QS_CONFIG_ADDR  ((volatile uint *)(PCI_CSR_ADDR + 0x500))
  88 #define QS_CONFIG_DATA  ((volatile uint *)(PCI_CSR_ADDR + 0x504))
  89
  90 #define mk_config_addr(bus, dev, offset) \
  91         (((bus)<<16) | ((dev)<<8) | (offset & 0xfc))
  92
  93 #define mk_config_type1(bus, dev, offset) \
  94         mk_config_addr(bus, dev, offset) | 1;
  95
  96 static DEFINE_SPINLOCK(pcibios_lock);
  97
  98 int qspan_pcibios_read_config_byte(unsigned char bus, unsigned char dev_fn,
  99                                   unsigned char offset, unsigned char *val)
 100 {
 101         uint    temp;
 102         u_char  *cp;
 103 #ifdef CONFIG_RPXCLASSIC
 104         unsigned long flags;
 105 #endif
 106
 107         if ((bus > 7) || (dev_fn > 127)) {
 108                 *val = 0xff;
 109                 return PCIBIOS_DEVICE_NOT_FOUND;
 110         }
 111
 112 #ifdef CONFIG_RPXCLASSIC
 113         /* disable interrupts */
 114         spin_lock_irqsave(&pcibios_lock, flags);
 115         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 116         eieio();
 117 #endif
 118
 119         if (bus == 0)
 120                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 121         else
 122                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 123         __get_qspan_pci_config(temp, QS_CONFIG_DATA, "lwz");
 124
 125 #ifdef CONFIG_RPXCLASSIC
 126         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 127         eieio();
 128         spin_unlock_irqrestore(&pcibios_lock, flags);
 129 #endif
 130
 131         offset ^= 0x03;
 132         cp = ((u_char *)&temp) + (offset & 0x03);
 133         *val = *cp;
 134         return PCIBIOS_SUCCESSFUL;
 135 }
 136
 137 int qspan_pcibios_read_config_word(unsigned char bus, unsigned char dev_fn,
 138                                   unsigned char offset, unsigned short *val)
 139 {
 140         uint    temp;
 141         ushort  *sp;
 142 #ifdef CONFIG_RPXCLASSIC
 143         unsigned long flags;
 144 #endif
 145
 146         if ((bus > 7) || (dev_fn > 127)) {
 147                 *val = 0xffff;
 148                 return PCIBIOS_DEVICE_NOT_FOUND;
 149         }
 150
 151 #ifdef CONFIG_RPXCLASSIC
 152         /* disable interrupts */
 153         spin_lock_irqsave(&pcibios_lock, flags);
 154         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 155         eieio();
 156 #endif
 157
 158         if (bus == 0)
 159                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 160         else
 161                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 162         __get_qspan_pci_config(temp, QS_CONFIG_DATA, "lwz");
 163         offset ^= 0x02;
 164
 165 #ifdef CONFIG_RPXCLASSIC
 166         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 167         eieio();
 168         spin_unlock_irqrestore(&pcibios_lock, flags);
 169 #endif
 170
 171         sp = ((ushort *)&temp) + ((offset >> 1) & 1);
 172         *val = *sp;
 173         return PCIBIOS_SUCCESSFUL;
 174 }
 175
 176 int qspan_pcibios_read_config_dword(unsigned char bus, unsigned char dev_fn,
 177                                    unsigned char offset, unsigned int *val)
 178 {
 179 #ifdef CONFIG_RPXCLASSIC
 180         unsigned long flags;
 181 #endif
 182
 183         if ((bus > 7) || (dev_fn > 127)) {
 184                 *val = 0xffffffff;
 185                 return PCIBIOS_DEVICE_NOT_FOUND;
 186         }
 187
 188 #ifdef CONFIG_RPXCLASSIC
 189         /* disable interrupts */
 190         spin_lock_irqsave(&pcibios_lock, flags);
 191         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 192         eieio();
 193 #endif
 194
 195         if (bus == 0)
 196                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 197         else
 198                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 199         __get_qspan_pci_config(*val, QS_CONFIG_DATA, "lwz");
 200
 201 #ifdef CONFIG_RPXCLASSIC
 202         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 203         eieio();
 204         spin_unlock_irqrestore(&pcibios_lock, flags);
 205 #endif
 206
 207         return PCIBIOS_SUCCESSFUL;
 208 }
 209
 210 int qspan_pcibios_write_config_byte(unsigned char bus, unsigned char dev_fn,
 211                                    unsigned char offset, unsigned char val)
 212 {
 213         uint    temp;
 214         u_char  *cp;
 215 #ifdef CONFIG_RPXCLASSIC
 216         unsigned long flags;
 217 #endif
 218
 219         if ((bus > 7) || (dev_fn > 127))
 220                 return PCIBIOS_DEVICE_NOT_FOUND;
 221
 222         qspan_pcibios_read_config_dword(bus, dev_fn, offset, &temp);
 223
 224         offset ^= 0x03;
 225         cp = ((u_char *)&temp) + (offset & 0x03);
 226         *cp = val;
 227
 228 #ifdef CONFIG_RPXCLASSIC
 229         /* disable interrupts */
 230         spin_lock_irqsave(&pcibios_lock, flags);
 231         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 232         eieio();
 233 #endif
 234
 235         if (bus == 0)
 236                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 237         else
 238                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 239         *QS_CONFIG_DATA = temp;
 240
 241 #ifdef CONFIG_RPXCLASSIC
 242         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 243         eieio();
 244         spin_unlock_irqrestore(&pcibios_lock, flags);
 245 #endif
 246
 247         return PCIBIOS_SUCCESSFUL;
 248 }
 249
 250 int qspan_pcibios_write_config_word(unsigned char bus, unsigned char dev_fn,
 251                                    unsigned char offset, unsigned short val)
 252 {
 253         uint    temp;
 254         ushort  *sp;
 255 #ifdef CONFIG_RPXCLASSIC
 256         unsigned long flags;
 257 #endif
 258
 259         if ((bus > 7) || (dev_fn > 127))
 260                 return PCIBIOS_DEVICE_NOT_FOUND;
 261
 262         qspan_pcibios_read_config_dword(bus, dev_fn, offset, &temp);
 263
 264         offset ^= 0x02;
 265         sp = ((ushort *)&temp) + ((offset >> 1) & 1);
 266         *sp = val;
 267
 268 #ifdef CONFIG_RPXCLASSIC
 269         /* disable interrupts */
 270         spin_lock_irqsave(&pcibios_lock, flags);
 271         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 272         eieio();
 273 #endif
 274
 275         if (bus == 0)
 276                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 277         else
 278                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 279         *QS_CONFIG_DATA = temp;
 280
 281 #ifdef CONFIG_RPXCLASSIC
 282         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 283         eieio();
 284         spin_unlock_irqrestore(&pcibios_lock, flags);
 285 #endif
 286
 287         return PCIBIOS_SUCCESSFUL;
 288 }
 289
 290 int qspan_pcibios_write_config_dword(unsigned char bus, unsigned char dev_fn,
 291                                     unsigned char offset, unsigned int val)
 292 {
 293 #ifdef CONFIG_RPXCLASSIC
 294         unsigned long flags;
 295 #endif
 296
 297         if ((bus > 7) || (dev_fn > 127))
 298                 return PCIBIOS_DEVICE_NOT_FOUND;
 299
 300 #ifdef CONFIG_RPXCLASSIC
 301         /* disable interrupts */
 302         spin_lock_irqsave(&pcibios_lock, flags);
 303         *((uint *)RPX_CSR_ADDR) &= ~BCSR2_QSPACESEL;
 304         eieio();
 305 #endif
 306
 307         if (bus == 0)
 308                 *QS_CONFIG_ADDR = mk_config_addr(bus, dev_fn, offset);
 309         else
 310                 *QS_CONFIG_ADDR = mk_config_type1(bus, dev_fn, offset);
 311         *(unsigned int *)QS_CONFIG_DATA = val;
 312
 313 #ifdef CONFIG_RPXCLASSIC
 314         *((uint *)RPX_CSR_ADDR) |= BCSR2_QSPACESEL;
 315         eieio();
 316         spin_unlock_irqrestore(&pcibios_lock, flags);
 317 #endif
 318
 319         return PCIBIOS_SUCCESSFUL;
 320 }
 321
 322 int qspan_pcibios_find_device(unsigned short vendor, unsigned short dev_id,
 323                              unsigned short index, unsigned char *bus_ptr,
 324                              unsigned char *dev_fn_ptr)
 325 {
 326     int num, devfn;
 327     unsigned int x, vendev;
 328
 329     if (vendor == 0xffff)
 330         return PCIBIOS_BAD_VENDOR_ID;
 331     vendev = (dev_id << 16) + vendor;
 332     num = 0;
 333     for (devfn = 0;  devfn < 32;  devfn++) {
 334         qspan_pcibios_read_config_dword(0, devfn<<3, PCI_VENDOR_ID, &x);
 335         if (x == vendev) {
 336             if (index == num) {
 337                 *bus_ptr = 0;
 338                 *dev_fn_ptr = devfn<<3;
 339                 return PCIBIOS_SUCCESSFUL;
 340             }
 341             ++num;
 342         }
 343     }
 344     return PCIBIOS_DEVICE_NOT_FOUND;
 345 }
 346
 347 int qspan_pcibios_find_class(unsigned int class_code, unsigned short index,
 348                             unsigned char *bus_ptr, unsigned char *dev_fn_ptr)
 349 {
 350     int devnr, x, num;
 351
 352     num = 0;
 353     for (devnr = 0;  devnr < 32;  devnr++) {
 354         qspan_pcibios_read_config_dword(0, devnr<<3, PCI_CLASS_REVISION, &x);
 355         if ((x>>8) == class_code) {
 356             if (index == num) {
 357                 *bus_ptr = 0;
 358                 *dev_fn_ptr = devnr<<3;
 359                 return PCIBIOS_SUCCESSFUL;
 360             }
 361             ++num;
 362         }
 363     }
 364     return PCIBIOS_DEVICE_NOT_FOUND;
 365 }
 366
 367 void __init
 368 m8xx_pcibios_fixup(void)
 369 {
 370    /* Lots to do here, all board and configuration specific. */
 371 }
 372
 373 void __init
 374 m8xx_setup_pci_ptrs(void)
 375 {
 376         set_config_access_method(qspan);
 377
 378         ppc_md.pcibios_fixup = m8xx_pcibios_fixup;
 379 }
 380