root/drivers/block/triton.c

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DEFINITIONS

This source file includes following definitions.
  1. dma_intr
  2. build_dmatable
  3. config_drive_for_dma
  4. triton_dmaproc
  5. print_triton_drive_flags
  6. ide_init_triton

   1 /*
   2  *  linux/drivers/block/triton.c        Version 1.02  Oct 13, 1995
   3  *
   4  *  Copyright (c) 1995  Mark Lord
   5  *  May be copied or modified under the terms of the GNU General Public License
   6  */
   7 
   8 /*
   9  * This module provides support for the Bus Master IDE DMA function
  10  * of the Intel PCI Triton chipset (82371FB).
  11  *
  12  * DMA is currently supported only for hard disk drives (not cdroms).
  13  *
  14  * Support for cdroms will likely be added at a later date,
  15  * after broader experience has been obtained with hard disks.
  16  *
  17  * Up to four drives may be enabled for DMA, and the Triton chipset will
  18  * (hopefully) arbitrate the PCI bus among them.  Note that the 82371FB chip
  19  * provides a single "line buffer" for the BM IDE function, so performance of
  20  * multiple (two) drives doing DMA simultaneously will suffer somewhat,
  21  * as they contest for that resource bottleneck.  This is handled transparently
  22  * inside the 82371FB chip.
  23  *
  24  * By default, DMA support is prepared for use, but is currently enabled only
  25  * for drives which support multi-word DMA mode2 (mword2), or which are
  26  * recognized as "good" (see table below).  Drives with only mode0 or mode1
  27  * (single or multi) DMA should also work with this chipset/driver (eg. MC2112A)
  28  * but are not enabled by default.  Use "hdparm -i" to view modes supported
  29  * by a given drive.
  30  *
  31  * The hdparm-2.4 (or later) utility can be used for manually enabling/disabling
  32  * DMA support, but must be (re-)compiled against this kernel version or later.
  33  *
  34  * To enable DMA, use "hdparm -d1 /dev/hd?" on a per-drive basis after booting.
  35  * If problems arise, ide.c will disable DMA operation after a few retries.
  36  * This error recovery mechanism works and has been extremely well exercised.
  37  *
  38  * IDE drives, depending on their vintage, may support several different modes
  39  * of DMA operation.  The boot-time modes are indicated with a "*" in
  40  * the "hdparm -i" listing, and can be changed with *knowledgeable* use of
  41  * the "hdparm -X" feature.  There is seldom a need to do this, as drives
  42  * normally power-up with their "best" PIO/DMA modes enabled.
  43  *
  44  * Testing was done with an ASUS P55TP4XE/100 system and the following drives:
  45  *
  46  *   Quantum Fireball 1080A (1Gig w/83kB buffer), DMA mode2, PIO mode4.
  47  *      - DMA mode2 works well (7.4MB/sec), despite the tiny on-drive buffer.
  48  *      - This drive also does PIO mode4, at about the same speed as DMA mode2.
  49  *        An awesome drive for the price!
  50  *
  51  *   Fujitsu M1606TA (1Gig w/256kB buffer), DMA mode2, PIO mode4.
  52  *      - DMA mode2 gives horrible performance (1.6MB/sec), despite the good
  53  *        size of the on-drive buffer and a boasted 10ms average access time.
  54  *      - PIO mode4 was better, but peaked at a mere 4.5MB/sec.
  55  *
  56  *   Micropolis MC2112A (1Gig w/508kB buffer), drive pre-dates EIDE and ATA2.
  57  *      - DMA works fine (2.2MB/sec), probably due to the large on-drive buffer.
  58  *      - This older drive can also be tweaked for fastPIO (3.7MB/sec) by using
  59  *        maximum clock settings (5,4) and setting all flags except prefetch.
  60  *
  61  *   Western Digital AC31000H (1Gig w/128kB buffer), DMA mode1, PIO mode3.
  62  *      - DMA does not work reliably.  The drive appears to be somewhat tardy
  63  *        in deasserting DMARQ at the end of a sector.  This is evident in
  64  *        the observation that WRITEs work most of the time, depending on
  65  *        cache-buffer occupancy, but multi-sector reads seldom work.
  66  *
  67  * Drives like the AC31000H could likely be made to work if all DMA were done
  68  * one sector at a time, but that would likely negate any advantage over PIO.
  69  *
  70  * If you have any drive models to add, email your results to:  mlord@bnr.ca
  71  * Keep an eye on /var/adm/messages for "DMA disabled" messages.
  72  */
  73 #define _TRITON_C
  74 #include <linux/config.h>
  75 #ifndef CONFIG_BLK_DEV_TRITON
  76 #define CONFIG_BLK_DEV_TRITON y
  77 #endif
  78 #include <linux/types.h>
  79 #include <linux/kernel.h>
  80 #include <linux/timer.h>
  81 #include <linux/mm.h>
  82 #include <linux/ioport.h>
  83 #include <linux/interrupt.h>
  84 #include <linux/blkdev.h>
  85 #include <linux/hdreg.h>
  86 #include <linux/pci.h>
  87 #include <linux/bios32.h>
  88 
  89 #include <asm/io.h>
  90 #include <asm/dma.h>
  91 
  92 #include "ide.h"
  93 
  94 /*
  95  * good_dma_drives() lists the model names (from "hdparm -i")
  96  * of drives which do not support mword2 DMA but which are
  97  * known to work fine with this interface under Linux.
  98  */
  99 const char *good_dma_drives[] = {"Micropolis 2112A"};
 100 
 101 /*
 102  * Our Physical Region Descriptor (PRD) table should be large enough
 103  * to handle the biggest I/O request we are likely to see.  Since requests
 104  * can have no more than 256 sectors, and since the typical blocksize is
 105  * two sectors, we can get by with a limit of 128 entries here for the
 106  * usual worst case.  Most requests seem to include some contiguous blocks,
 107  * further reducing the number of table entries required.
 108  *
 109  * Note that the driver reverts to PIO mode for individual requests that exceed
 110  * this limit (possible with 512 byte blocksizes, eg. MSDOS f/s), so handling
 111  * 100% of all crazy scenarios here is not necessary.
 112  *
 113  * As it turns out, though, we must allocate a full 4KB page for this,
 114  * so the two PRD tables (ide0 & ide1) will each get half of that,
 115  * allowing each to have about 256 entries (8 bytes each) from this.
 116  */
 117 #define PRD_BYTES       8
 118 #define PRD_ENTRIES     (PAGE_SIZE / (2 * PRD_BYTES))
 119 
 120 /*
 121  * dma_intr() is the handler for disk read/write DMA interrupts
 122  */
 123 static void dma_intr (ide_drive_t *drive)
     /* [previous][next][first][last][top][bottom][index][help] */
 124 {
 125         byte stat, dma_stat;
 126         int i;
 127         struct request *rq = HWGROUP(drive)->rq;
 128         unsigned short dma_base = HWIF(drive)->dma_base;
 129 
 130         dma_stat = inb(dma_base+2);             /* get DMA status */
 131         outb(inb(dma_base)&~1, dma_base);       /* stop DMA operation */
 132         stat = GET_STAT();                      /* get drive status */
 133         if (OK_STAT(stat,DRIVE_READY,drive->bad_wstat|DRQ_STAT)) {
 134                 if ((dma_stat & 7) == 4) {      /* verify good DMA status */
 135                         rq = HWGROUP(drive)->rq;
 136                         for (i = rq->nr_sectors; i > 0;) {
 137                                 i -= rq->current_nr_sectors;
 138                                 ide_end_request(1, HWGROUP(drive));
 139                         }
 140                         IDE_DO_REQUEST;
 141                         return;
 142                 }
 143                 printk("%s: bad DMA status: 0x%02x\n", drive->name, dma_stat);
 144         }
 145         sti();
 146         if (!ide_error(drive, "dma_intr", stat))
 147                 IDE_DO_REQUEST;
 148 }
 149 
 150 /*
 151  * build_dmatable() prepares a dma request.
 152  * Returns 0 if all went okay, returns 1 otherwise.
 153  */
 154 static int build_dmatable (ide_drive_t *drive)
     /* [previous][next][first][last][top][bottom][index][help] */
 155 {
 156         struct request *rq = HWGROUP(drive)->rq;
 157         struct buffer_head *bh = rq->bh;
 158         unsigned long size, addr, *table = HWIF(drive)->dmatable;
 159         unsigned int count = 0;
 160 
 161         do {
 162                 /*
 163                  * Determine addr and size of next buffer area.  We assume that
 164                  * individual virtual buffers are always composed linearly in
 165                  * physical memory.  For example, we assume that any 8kB buffer
 166                  * is always composed of two adjacent physical 4kB pages rather
 167                  * than two possibly non-adjacent physical 4kB pages.
 168                  */
 169                 if (bh == NULL) {  /* paging requests have (rq->bh == NULL) */
 170                         addr = virt_to_bus (rq->buffer);
 171                         size = rq->nr_sectors << 9;
 172                 } else {
 173                         /* group sequential buffers into one large buffer */
 174                         addr = virt_to_bus (bh->b_data);
 175                         size = bh->b_size;
 176                         while ((bh = bh->b_reqnext) != NULL) {
 177                                 if ((addr + size) != virt_to_bus (bh->b_data))
 178                                         break;
 179                                 size += bh->b_size;
 180                         }
 181                 }
 182 
 183                 /*
 184                  * Fill in the dma table, without crossing any 64kB boundaries.
 185                  * We assume 16-bit alignment of all blocks.
 186                  */
 187                 while (size) {
 188                         if (++count >= PRD_ENTRIES) {
 189                                 printk("%s: DMA table too small\n", drive->name);
 190                                 return 1; /* revert to PIO for this request */
 191                         } else {
 192                                 unsigned long bcount = 0x10000 - (addr & 0xffff);
 193                                 if (bcount > size)
 194                                         bcount = size;
 195                                 *table++ = addr;
 196                                 *table++ = bcount;
 197                                 addr += bcount;
 198                                 size -= bcount;
 199                         }
 200                 }
 201         } while (bh != NULL);
 202         if (count) {
 203                 *--table |= 0x80000000; /* set End-Of-Table (EOT) bit */
 204                 return 0;
 205         }
 206         printk("%s: empty DMA table?\n", drive->name);
 207         return 1;       /* let the PIO routines handle this weirdness */
 208 }
 209 
 210 static int config_drive_for_dma (ide_drive_t *drive)
     /* [previous][next][first][last][top][bottom][index][help] */
 211 {
 212         const char **list;
 213 
 214         struct hd_driveid *id = drive->id;
 215         if (id && (id->capability & 1)) {
 216                 /* Enable DMA on any drive that supports mword2 DMA */
 217                 if ((id->field_valid & 2) && (id->dma_mword & 0x404) == 0x404) {
 218                         drive->using_dma = 1;
 219                         return 0;               /* DMA enabled */
 220                 }
 221                 /* Consult the list of known "good" drives */
 222                 list = good_dma_drives;
 223                 while (*list) {
 224                         if (!strcmp(*list++,id->model)) {
 225                                 drive->using_dma = 1;
 226                                 return 0;       /* DMA enabled */
 227                         }
 228                 }
 229         }
 230         return 1;       /* DMA not enabled */
 231 }
 232 
 233 /*
 234  * triton_dmaproc() initiates/aborts DMA read/write operations on a drive.
 235  *
 236  * The caller is assumed to have selected the drive and programmed the drive's
 237  * sector address using CHS or LBA.  All that remains is to prepare for DMA
 238  * and then issue the actual read/write DMA/PIO command to the drive.
 239  *
 240  * Returns 0 if all went well.
 241  * Returns 1 if DMA read/write could not be started, in which case
 242  * the caller should revert to PIO for the current request.
 243  */
 244 static int triton_dmaproc (ide_dma_action_t func, ide_drive_t *drive)
     /* [previous][next][first][last][top][bottom][index][help] */
 245 {
 246         unsigned long dma_base = HWIF(drive)->dma_base;
 247         unsigned int reading = (1 << 3);
 248 
 249         switch (func) {
 250                 case ide_dma_abort:
 251                         outb(inb(dma_base)&~1, dma_base);       /* stop DMA */
 252                         return 0;
 253                 case ide_dma_check:
 254                         return config_drive_for_dma (drive);
 255                 case ide_dma_write:
 256                         reading = 0;
 257                 case ide_dma_read:
 258                         break;
 259                 default:
 260                         printk("triton_dmaproc: unsupported func: %d\n", func);
 261                         return 1;
 262         }
 263         if (build_dmatable (drive))
 264                 return 1;
 265         outl(virt_to_bus (HWIF(drive)->dmatable), dma_base + 4); /* PRD table */
 266         outb(reading, dma_base);                        /* specify r/w */
 267         outb(0x26, dma_base+2);                         /* clear status bits */
 268         ide_set_handler (drive, &dma_intr);             /* issue cmd to drive */
 269         OUT_BYTE(reading ? WIN_READDMA : WIN_WRITEDMA, IDE_COMMAND_REG);
 270         outb(inb(dma_base)|1, dma_base);                /* begin DMA */
 271         return 0;
 272 }
 273 
 274 /*
 275  * print_triton_drive_flags() displays the currently programmed options
 276  * in the Triton chipset for a given drive.
 277  *
 278  *      If fastDMA  is "no", then slow ISA timings are used for DMA data xfers.
 279  *      If fastPIO  is "no", then slow ISA timings are used for PIO data xfers.
 280  *      If IORDY    is "no", then IORDY is assumed to always be asserted.
 281  *      If PreFetch is "no", then data pre-fetch/post are not used.
 282  *
 283  * When "fastPIO" and/or "fastDMA" are "yes", then faster PCI timings and
 284  * back-to-back 16-bit data transfers are enabled, using the sample_CLKs
 285  * and recovery_CLKs (PCI clock cycles) timing parameters for that interface.
 286  */
 287 static void print_triton_drive_flags (unsigned int unit, byte flags)
     /* [previous][next][first][last][top][bottom][index][help] */
 288 {
 289         printk("         %s ", unit ? "slave :" : "master:");
 290         printk( "fastDMA=%s",   (flags&9)       ? "on " : "off");
 291         printk(" PreFetch=%s",  (flags&4)       ? "on " : "off");
 292         printk(" IORDY=%s",     (flags&2)       ? "on " : "off");
 293         printk(" fastPIO=%s\n", ((flags&9)==1)  ? "on " : "off");
 294 }
 295 
 296 /*
 297  * ide_init_triton() prepares the IDE driver for DMA operation.
 298  * This routine is called once, from ide.c during driver initialization,
 299  * for each triton chipset which is found (unlikely to be more than one).
 300  */
 301 void ide_init_triton (byte bus, byte fn)
     /* [previous][next][first][last][top][bottom][index][help] */
 302 {
 303         int rc = 0, h;
 304         unsigned short bmiba, pcicmd;
 305         unsigned int timings;
 306         unsigned char *dmatable = NULL;
 307         extern ide_hwif_t ide_hwifs[];
 308 
 309         /*
 310          * See if IDE and BM-DMA features are enabled:
 311          */
 312         if ((rc = pcibios_read_config_word(bus, fn, 0x04, &pcicmd)))
 313                 goto quit;
 314         if ((pcicmd & 5) != 5) {
 315                 if ((pcicmd & 1) == 0)
 316                         printk("ide: Triton IDE ports are not enabled\n");
 317                 else
 318                         printk("ide: Triton BM-DMA feature is not enabled\n");
 319                 goto quit;
 320         }
 321 #if 0
 322         (void) pcibios_write_config_word(bus, fn, 0x42, 0x8037); /* for my MC2112A */
 323 #endif
 324         /*
 325          * See if ide port(s) are enabled
 326          */
 327         if ((rc = pcibios_read_config_dword(bus, fn, 0x40, &timings)))
 328                 goto quit;
 329         if (!(timings & 0x80008000)) {
 330                 printk("ide: Triton IDE ports are not enabled\n");
 331                 goto quit;
 332         }
 333         printk("ide: Triton BM-IDE on PCI bus %d function %d\n", bus, fn);
 334 
 335         /*
 336          * Get the bmiba base address
 337          */
 338         if ((rc = pcibios_read_config_word(bus, fn, 0x20, &bmiba)))
 339                 goto quit;
 340         bmiba &= 0xfff0;        /* extract port base address */
 341 
 342         /*
 343          * Save the dma_base port addr for each interface
 344          */
 345         for (h = 0; h < MAX_HWIFS; ++h) {
 346                 ide_hwif_t *hwif = &ide_hwifs[h];
 347                 unsigned short base, time;
 348                 if (hwif->io_base == 0x1f0 && (timings & 0x8000)) {
 349                         time = timings & 0xffff;
 350                         base = bmiba;
 351                 } else if (hwif->io_base == 0x170 && (timings & 0x80000000)) {
 352                         time = timings >> 16;
 353                         base = bmiba + 8;
 354                 } else
 355                         continue;
 356                 printk("    %s: BusMaster DMA at 0x%04x-0x%04x", hwif->name, base, base+7);
 357                 if (check_region(base, 8)) {
 358                         printk(" -- ERROR, PORTS ALREADY IN USE");
 359                 } else {
 360                         request_region(base, 8, hwif->name);
 361                         hwif->dma_base = base;
 362                         if (dmatable == NULL) {
 363                                 /*
 364                                  * Since we know we are on a PCI bus, we could
 365                                  * actually use __get_free_pages() here instead
 366                                  * of __get_dma_pages() -- no ISA limitations.
 367                                  */
 368                                 dmatable = (void *) __get_dma_pages(GFP_KERNEL, 0);
 369                         }
 370                         if (dmatable != NULL) {
 371                                 hwif->dmatable = (unsigned long *) dmatable;
 372                                 dmatable += (PRD_ENTRIES * PRD_BYTES);
 373                                 outl(virt_to_bus(hwif->dmatable), base + 4);
 374                                 hwif->dmaproc  = &triton_dmaproc;
 375                         }
 376                 }
 377                 printk("\n    %s timing: (0x%04x) sample_CLKs=%d, recovery_CLKs=%d\n",
 378                  hwif->name, time, ((~time>>12)&3)+2, ((~time>>8)&3)+1);
 379                 print_triton_drive_flags (0, time & 0xf);
 380                 print_triton_drive_flags (1, (time >> 4) & 0xf);
 381         }
 382 
 383 quit: if (rc) printk("ide: pcibios access failed - %s\n", pcibios_strerror(rc));
 384 }
 385 

/* [previous][next][first][last][top][bottom][index][help] */