arch/powerpc/platforms/powernv/opal-lpc.c

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This source file includes following definitions.
opal_lpc_inb
__opal_lpc_inw
opal_lpc_inw
__opal_lpc_inl
opal_lpc_inl
opal_lpc_outb
__opal_lpc_outw
opal_lpc_outw
__opal_lpc_outl
opal_lpc_outl
opal_lpc_insb
opal_lpc_insw
opal_lpc_insl
opal_lpc_outsb
opal_lpc_outsw
opal_lpc_outsl
lpc_debug_read
lpc_debug_write
opal_lpc_debugfs_create_type
opal_lpc_init_debugfs
opal_lpc_init
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * PowerNV LPC bus handling.
   4  *
   5  * Copyright 2013 IBM Corp.
   6  */
   7 
   8 #include <linux/kernel.h>
   9 #include <linux/of.h>
  10 #include <linux/bug.h>
  11 #include <linux/io.h>
  12 #include <linux/slab.h>
  13 
  14 #include <asm/machdep.h>
  15 #include <asm/firmware.h>
  16 #include <asm/opal.h>
  17 #include <asm/prom.h>
  18 #include <linux/uaccess.h>
  19 #include <asm/debugfs.h>
  20 #include <asm/isa-bridge.h>
  21 
  22 static int opal_lpc_chip_id = -1;
  23 
  24 static u8 opal_lpc_inb(unsigned long port)
  25 {
  26         int64_t rc;
  27         __be32 data;
  28 
  29         if (opal_lpc_chip_id < 0 || port > 0xffff)
  30                 return 0xff;
  31         rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 1);
  32         return rc ? 0xff : be32_to_cpu(data);
  33 }
  34 
  35 static __le16 __opal_lpc_inw(unsigned long port)
  36 {
  37         int64_t rc;
  38         __be32 data;
  39 
  40         if (opal_lpc_chip_id < 0 || port > 0xfffe)
  41                 return 0xffff;
  42         if (port & 1)
  43                 return (__le16)opal_lpc_inb(port) << 8 | opal_lpc_inb(port + 1);
  44         rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 2);
  45         return rc ? 0xffff : be32_to_cpu(data);
  46 }
  47 static u16 opal_lpc_inw(unsigned long port)
  48 {
  49         return le16_to_cpu(__opal_lpc_inw(port));
  50 }
  51 
  52 static __le32 __opal_lpc_inl(unsigned long port)
  53 {
  54         int64_t rc;
  55         __be32 data;
  56 
  57         if (opal_lpc_chip_id < 0 || port > 0xfffc)
  58                 return 0xffffffff;
  59         if (port & 3)
  60                 return (__le32)opal_lpc_inb(port    ) << 24 |
  61                        (__le32)opal_lpc_inb(port + 1) << 16 |
  62                        (__le32)opal_lpc_inb(port + 2) <<  8 |
  63                                opal_lpc_inb(port + 3);
  64         rc = opal_lpc_read(opal_lpc_chip_id, OPAL_LPC_IO, port, &data, 4);
  65         return rc ? 0xffffffff : be32_to_cpu(data);
  66 }
  67 
  68 static u32 opal_lpc_inl(unsigned long port)
  69 {
  70         return le32_to_cpu(__opal_lpc_inl(port));
  71 }
  72 
  73 static void opal_lpc_outb(u8 val, unsigned long port)
  74 {
  75         if (opal_lpc_chip_id < 0 || port > 0xffff)
  76                 return;
  77         opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 1);
  78 }
  79 
  80 static void __opal_lpc_outw(__le16 val, unsigned long port)
  81 {
  82         if (opal_lpc_chip_id < 0 || port > 0xfffe)
  83                 return;
  84         if (port & 1) {
  85                 opal_lpc_outb(val >> 8, port);
  86                 opal_lpc_outb(val     , port + 1);
  87                 return;
  88         }
  89         opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 2);
  90 }
  91 
  92 static void opal_lpc_outw(u16 val, unsigned long port)
  93 {
  94         __opal_lpc_outw(cpu_to_le16(val), port);
  95 }
  96 
  97 static void __opal_lpc_outl(__le32 val, unsigned long port)
  98 {
  99         if (opal_lpc_chip_id < 0 || port > 0xfffc)
 100                 return;
 101         if (port & 3) {
 102                 opal_lpc_outb(val >> 24, port);
 103                 opal_lpc_outb(val >> 16, port + 1);
 104                 opal_lpc_outb(val >>  8, port + 2);
 105                 opal_lpc_outb(val      , port + 3);
 106                 return;
 107         }
 108         opal_lpc_write(opal_lpc_chip_id, OPAL_LPC_IO, port, val, 4);
 109 }
 110 
 111 static void opal_lpc_outl(u32 val, unsigned long port)
 112 {
 113         __opal_lpc_outl(cpu_to_le32(val), port);
 114 }
 115 
 116 static void opal_lpc_insb(unsigned long p, void *b, unsigned long c)
 117 {
 118         u8 *ptr = b;
 119 
 120         while(c--)
 121                 *(ptr++) = opal_lpc_inb(p);
 122 }
 123 
 124 static void opal_lpc_insw(unsigned long p, void *b, unsigned long c)
 125 {
 126         __le16 *ptr = b;
 127 
 128         while(c--)
 129                 *(ptr++) = __opal_lpc_inw(p);
 130 }
 131 
 132 static void opal_lpc_insl(unsigned long p, void *b, unsigned long c)
 133 {
 134         __le32 *ptr = b;
 135 
 136         while(c--)
 137                 *(ptr++) = __opal_lpc_inl(p);
 138 }
 139 
 140 static void opal_lpc_outsb(unsigned long p, const void *b, unsigned long c)
 141 {
 142         const u8 *ptr = b;
 143 
 144         while(c--)
 145                 opal_lpc_outb(*(ptr++), p);
 146 }
 147 
 148 static void opal_lpc_outsw(unsigned long p, const void *b, unsigned long c)
 149 {
 150         const __le16 *ptr = b;
 151 
 152         while(c--)
 153                 __opal_lpc_outw(*(ptr++), p);
 154 }
 155 
 156 static void opal_lpc_outsl(unsigned long p, const void *b, unsigned long c)
 157 {
 158         const __le32 *ptr = b;
 159 
 160         while(c--)
 161                 __opal_lpc_outl(*(ptr++), p);
 162 }
 163 
 164 static const struct ppc_pci_io opal_lpc_io = {
 165         .inb    = opal_lpc_inb,
 166         .inw    = opal_lpc_inw,
 167         .inl    = opal_lpc_inl,
 168         .outb   = opal_lpc_outb,
 169         .outw   = opal_lpc_outw,
 170         .outl   = opal_lpc_outl,
 171         .insb   = opal_lpc_insb,
 172         .insw   = opal_lpc_insw,
 173         .insl   = opal_lpc_insl,
 174         .outsb  = opal_lpc_outsb,
 175         .outsw  = opal_lpc_outsw,
 176         .outsl  = opal_lpc_outsl,
 177 };
 178 
 179 #ifdef CONFIG_DEBUG_FS
 180 struct lpc_debugfs_entry {
 181         enum OpalLPCAddressType lpc_type;
 182 };
 183 
 184 static ssize_t lpc_debug_read(struct file *filp, char __user *ubuf,
 185                               size_t count, loff_t *ppos)
 186 {
 187         struct lpc_debugfs_entry *lpc = filp->private_data;
 188         u32 data, pos, len, todo;
 189         int rc;
 190 
 191         if (!access_ok(ubuf, count))
 192                 return -EFAULT;
 193 
 194         todo = count;
 195         while (todo) {
 196                 pos = *ppos;
 197 
 198                 /*
 199                  * Select access size based on count and alignment and
 200                  * access type. IO and MEM only support byte acceses,
 201                  * FW supports all 3.
 202                  */
 203                 len = 1;
 204                 if (lpc->lpc_type == OPAL_LPC_FW) {
 205                         if (todo > 3 && (pos & 3) == 0)
 206                                 len = 4;
 207                         else if (todo > 1 && (pos & 1) == 0)
 208                                 len = 2;
 209                 }
 210                 rc = opal_lpc_read(opal_lpc_chip_id, lpc->lpc_type, pos,
 211                                    &data, len);
 212                 if (rc)
 213                         return -ENXIO;
 214 
 215                 /*
 216                  * Now there is some trickery with the data returned by OPAL
 217                  * as it's the desired data right justified in a 32-bit BE
 218                  * word.
 219                  *
 220                  * This is a very bad interface and I'm to blame for it :-(
 221                  *
 222                  * So we can't just apply a 32-bit swap to what comes from OPAL,
 223                  * because user space expects the *bytes* to be in their proper
 224                  * respective positions (ie, LPC position).
 225                  *
 226                  * So what we really want to do here is to shift data right
 227                  * appropriately on a LE kernel.
 228                  *
 229                  * IE. If the LPC transaction has bytes B0, B1, B2 and B3 in that
 230                  * order, we have in memory written to by OPAL at the "data"
 231                  * pointer:
 232                  *
 233                  *               Bytes:      OPAL "data"   LE "data"
 234                  *   32-bit:   B0 B1 B2 B3   B0B1B2B3      B3B2B1B0
 235                  *   16-bit:   B0 B1         0000B0B1      B1B00000
 236                  *    8-bit:   B0            000000B0      B0000000
 237                  *
 238                  * So a BE kernel will have the leftmost of the above in the MSB
 239                  * and rightmost in the LSB and can just then "cast" the u32 "data"
 240                  * down to the appropriate quantity and write it.
 241                  *
 242                  * However, an LE kernel can't. It doesn't need to swap because a
 243                  * load from data followed by a store to user are going to preserve
 244                  * the byte ordering which is the wire byte order which is what the
 245                  * user wants, but in order to "crop" to the right size, we need to
 246                  * shift right first.
 247                  */
 248                 switch(len) {
 249                 case 4:
 250                         rc = __put_user((u32)data, (u32 __user *)ubuf);
 251                         break;
 252                 case 2:
 253 #ifdef __LITTLE_ENDIAN__
 254                         data >>= 16;
 255 #endif
 256                         rc = __put_user((u16)data, (u16 __user *)ubuf);
 257                         break;
 258                 default:
 259 #ifdef __LITTLE_ENDIAN__
 260                         data >>= 24;
 261 #endif
 262                         rc = __put_user((u8)data, (u8 __user *)ubuf);
 263                         break;
 264                 }
 265                 if (rc)
 266                         return -EFAULT;
 267                 *ppos += len;
 268                 ubuf += len;
 269                 todo -= len;
 270         }
 271 
 272         return count;
 273 }
 274 
 275 static ssize_t lpc_debug_write(struct file *filp, const char __user *ubuf,
 276                                size_t count, loff_t *ppos)
 277 {
 278         struct lpc_debugfs_entry *lpc = filp->private_data;
 279         u32 data, pos, len, todo;
 280         int rc;
 281 
 282         if (!access_ok(ubuf, count))
 283                 return -EFAULT;
 284 
 285         todo = count;
 286         while (todo) {
 287                 pos = *ppos;
 288 
 289                 /*
 290                  * Select access size based on count and alignment and
 291                  * access type. IO and MEM only support byte acceses,
 292                  * FW supports all 3.
 293                  */
 294                 len = 1;
 295                 if (lpc->lpc_type == OPAL_LPC_FW) {
 296                         if (todo > 3 && (pos & 3) == 0)
 297                                 len = 4;
 298                         else if (todo > 1 && (pos & 1) == 0)
 299                                 len = 2;
 300                 }
 301 
 302                 /*
 303                  * Similarly to the read case, we have some trickery here but
 304                  * it's different to handle. We need to pass the value to OPAL in
 305                  * a register whose layout depends on the access size. We want
 306                  * to reproduce the memory layout of the user, however we aren't
 307                  * doing a load from user and a store to another memory location
 308                  * which would achieve that. Here we pass the value to OPAL via
 309                  * a register which is expected to contain the "BE" interpretation
 310                  * of the byte sequence. IE: for a 32-bit access, byte 0 should be
 311                  * in the MSB. So here we *do* need to byteswap on LE.
 312                  *
 313                  *           User bytes:    LE "data"  OPAL "data"
 314                  *  32-bit:  B0 B1 B2 B3    B3B2B1B0   B0B1B2B3
 315                  *  16-bit:  B0 B1          0000B1B0   0000B0B1
 316                  *   8-bit:  B0             000000B0   000000B0
 317                  */
 318                 switch(len) {
 319                 case 4:
 320                         rc = __get_user(data, (u32 __user *)ubuf);
 321                         data = cpu_to_be32(data);
 322                         break;
 323                 case 2:
 324                         rc = __get_user(data, (u16 __user *)ubuf);
 325                         data = cpu_to_be16(data);
 326                         break;
 327                 default:
 328                         rc = __get_user(data, (u8 __user *)ubuf);
 329                         break;
 330                 }
 331                 if (rc)
 332                         return -EFAULT;
 333 
 334                 rc = opal_lpc_write(opal_lpc_chip_id, lpc->lpc_type, pos,
 335                                     data, len);
 336                 if (rc)
 337                         return -ENXIO;
 338                 *ppos += len;
 339                 ubuf += len;
 340                 todo -= len;
 341         }
 342 
 343         return count;
 344 }
 345 
 346 static const struct file_operations lpc_fops = {
 347         .read =         lpc_debug_read,
 348         .write =        lpc_debug_write,
 349         .open =         simple_open,
 350         .llseek =       default_llseek,
 351 };
 352 
 353 static int opal_lpc_debugfs_create_type(struct dentry *folder,
 354                                         const char *fname,
 355                                         enum OpalLPCAddressType type)
 356 {
 357         struct lpc_debugfs_entry *entry;
 358         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 359         if (!entry)
 360                 return -ENOMEM;
 361         entry->lpc_type = type;
 362         debugfs_create_file(fname, 0600, folder, entry, &lpc_fops);
 363         return 0;
 364 }
 365 
 366 static int opal_lpc_init_debugfs(void)
 367 {
 368         struct dentry *root;
 369         int rc = 0;
 370 
 371         if (opal_lpc_chip_id < 0)
 372                 return -ENODEV;
 373 
 374         root = debugfs_create_dir("lpc", powerpc_debugfs_root);
 375 
 376         rc |= opal_lpc_debugfs_create_type(root, "io", OPAL_LPC_IO);
 377         rc |= opal_lpc_debugfs_create_type(root, "mem", OPAL_LPC_MEM);
 378         rc |= opal_lpc_debugfs_create_type(root, "fw", OPAL_LPC_FW);
 379         return rc;
 380 }
 381 machine_device_initcall(powernv, opal_lpc_init_debugfs);
 382 #endif  /* CONFIG_DEBUG_FS */
 383 
 384 void __init opal_lpc_init(void)
 385 {
 386         struct device_node *np;
 387 
 388         /*
 389          * Look for a Power8 LPC bus tagged as "primary",
 390          * we currently support only one though the OPAL APIs
 391          * support any number.
 392          */
 393         for_each_compatible_node(np, NULL, "ibm,power8-lpc") {
 394                 if (!of_device_is_available(np))
 395                         continue;
 396                 if (!of_get_property(np, "primary", NULL))
 397                         continue;
 398                 opal_lpc_chip_id = of_get_ibm_chip_id(np);
 399                 break;
 400         }
 401         if (opal_lpc_chip_id < 0)
 402                 return;
 403 
 404         /* Does it support direct mapping ? */
 405         if (of_get_property(np, "ranges", NULL)) {
 406                 pr_info("OPAL: Found memory mapped LPC bus on chip %d\n",
 407                         opal_lpc_chip_id);
 408                 isa_bridge_init_non_pci(np);
 409         } else {
 410                 pr_info("OPAL: Found non-mapped LPC bus on chip %d\n",
 411                         opal_lpc_chip_id);
 412 
 413                 /* Setup special IO ops */
 414                 ppc_pci_io = opal_lpc_io;
 415                 isa_io_special = true;
 416         }
 417 }
/* [<][>][^][v][top][bottom][index][help] */
root/arch/powerpc/platforms/powernv/opal-lpc.c

DEFINITIONS
