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1.1     ! root        1: /*
        !             2:  *  linux/drivers/block/triton.c       Version 1.06  Feb 6, 1996
        !             3:  *
        !             4:  *  Copyright (c) 1995-1996  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:  * Testing was done with a Gigabyte GA-586 ATE system and the following drive:
        !            68:  * (Uwe Bonnes - [email protected])
        !            69:  *
        !            70:  *   Western Digital AC31600H (1.6Gig w/128kB buffer), DMA mode2, PIO mode4.
        !            71:  *     - much better than its 1Gig cousin, this drive is reported to work
        !            72:  *       very well with DMA (7.3MB/sec).
        !            73:  *
        !            74:  * Other drives:
        !            75:  *
        !            76:  *   Maxtor 7540AV (515Meg w/32kB buffer), DMA modes mword0/sword2, PIO mode3.
        !            77:  *     - a budget drive, with budget performance, around 3MB/sec.
        !            78:  *
        !            79:  *   Western Digital AC2850F (814Meg w/64kB buffer), DMA mode1, PIO mode3.
        !            80:  *     - another "caviar" drive, similar to the AC31000, except that this one
        !            81:  *       worked with DMA in at least one system.  Throughput is about 3.8MB/sec
        !            82:  *       for both DMA and PIO.
        !            83:  *
        !            84:  *   Conner CFS850A (812Meg w/64kB buffer), DMA mode2, PIO mode4.
        !            85:  *     - like most Conner models, this drive proves that even a fast interface
        !            86:  *       cannot improve slow media.  Both DMA and PIO peak around 3.5MB/sec.
        !            87:  *
        !            88:  * If you have any drive models to add, email your results to:  [email protected]
        !            89:  * Keep an eye on /var/adm/messages for "DMA disabled" messages.
        !            90:  *
        !            91:  * Some people have reported trouble with Intel Zappa motherboards.
        !            92:  * This can be fixed by upgrading the AMI BIOS to version 1.00.04.BS0,
        !            93:  * available from ftp://ftp.intel.com/pub/bios/10004bs0.exe
        !            94:  * (thanks to Glen Morrell <[email protected]> for researching this).
        !            95:  *
        !            96:  * And, yes, Intel Zappa boards really *do* use the Triton IDE ports.
        !            97:  */
        !            98: #include <linux/config.h>
        !            99: #include <linux/types.h>
        !           100: #include <linux/kernel.h>
        !           101: #include <linux/timer.h>
        !           102: #include <linux/mm.h>
        !           103: #include <linux/ioport.h>
        !           104: #include <linux/interrupt.h>
        !           105: #include <linux/blkdev.h>
        !           106: #include <linux/hdreg.h>
        !           107: #include <linux/pci.h>
        !           108: #include <linux/bios32.h>
        !           109: 
        !           110: #include <asm/io.h>
        !           111: #include <asm/dma.h>
        !           112: 
        !           113: #include "ide.h"
        !           114: 
        !           115: /*
        !           116:  * good_dma_drives() lists the model names (from "hdparm -i")
        !           117:  * of drives which do not support mword2 DMA but which are
        !           118:  * known to work fine with this interface under Linux.
        !           119:  */
        !           120: const char *good_dma_drives[] = {"Micropolis 2112A",
        !           121:                                 "CONNER CTMA 4000"};
        !           122: 
        !           123: /*
        !           124:  * Our Physical Region Descriptor (PRD) table should be large enough
        !           125:  * to handle the biggest I/O request we are likely to see.  Since requests
        !           126:  * can have no more than 256 sectors, and since the typical blocksize is
        !           127:  * two sectors, we could get by with a limit of 128 entries here for the
        !           128:  * usual worst case.  Most requests seem to include some contiguous blocks,
        !           129:  * further reducing the number of table entries required.
        !           130:  *
        !           131:  * The driver reverts to PIO mode for individual requests that exceed
        !           132:  * this limit (possible with 512 byte blocksizes, eg. MSDOS f/s), so handling
        !           133:  * 100% of all crazy scenarios here is not necessary.
        !           134:  *
        !           135:  * As it turns out though, we must allocate a full 4KB page for this,
        !           136:  * so the two PRD tables (ide0 & ide1) will each get half of that,
        !           137:  * allowing each to have about 256 entries (8 bytes each) from this.
        !           138:  */
        !           139: #define PRD_BYTES      8
        !           140: #define PRD_ENTRIES    (PAGE_SIZE / (2 * PRD_BYTES))
        !           141: 
        !           142: /*
        !           143:  * dma_intr() is the handler for disk read/write DMA interrupts
        !           144:  */
        !           145: static void dma_intr (ide_drive_t *drive)
        !           146: {
        !           147:        byte stat, dma_stat;
        !           148:        int i;
        !           149:        struct request *rq = HWGROUP(drive)->rq;
        !           150:        unsigned short dma_base = HWIF(drive)->dma_base;
        !           151: 
        !           152:        dma_stat = inb(dma_base+2);             /* get DMA status */
        !           153:        outb(inb(dma_base)&~1, dma_base);       /* stop DMA operation */
        !           154:        stat = GET_STAT();                      /* get drive status */
        !           155:        if (OK_STAT(stat,DRIVE_READY,drive->bad_wstat|DRQ_STAT)) {
        !           156:                if ((dma_stat & 7) == 4) {      /* verify good DMA status */
        !           157:                        rq = HWGROUP(drive)->rq;
        !           158:                        for (i = rq->nr_sectors; i > 0;) {
        !           159:                                i -= rq->current_nr_sectors;
        !           160:                                ide_end_request(1, HWGROUP(drive));
        !           161:                        }
        !           162:                        return;
        !           163:                }
        !           164:                printk("%s: bad DMA status: 0x%02x\n", drive->name, dma_stat);
        !           165:        }
        !           166:        sti();
        !           167:        ide_error(drive, "dma_intr", stat);
        !           168: }
        !           169: 
        !           170: /*
        !           171:  * build_dmatable() prepares a dma request.
        !           172:  * Returns 0 if all went okay, returns 1 otherwise.
        !           173:  */
        !           174: static int build_dmatable (ide_drive_t *drive)
        !           175: {
        !           176:        struct request *rq = HWGROUP(drive)->rq;
        !           177:        struct buffer_head *bh = rq->bh;
        !           178:        unsigned long size, addr, *table = HWIF(drive)->dmatable;
        !           179:        unsigned int count = 0;
        !           180: 
        !           181:        do {
        !           182:                /*
        !           183:                 * Determine addr and size of next buffer area.  We assume that
        !           184:                 * individual virtual buffers are always composed linearly in
        !           185:                 * physical memory.  For example, we assume that any 8kB buffer
        !           186:                 * is always composed of two adjacent physical 4kB pages rather
        !           187:                 * than two possibly non-adjacent physical 4kB pages.
        !           188:                 */
        !           189:                if (bh == NULL) {  /* paging and tape requests have (rq->bh == NULL) */
        !           190:                        addr = virt_to_bus (rq->buffer);
        !           191: #ifdef CONFIG_BLK_DEV_IDETAPE
        !           192:                        if (drive->media == ide_tape)
        !           193:                                size = drive->tape.pc->request_transfer;
        !           194:                        else
        !           195: #endif /* CONFIG_BLK_DEV_IDETAPE */    
        !           196:                        size = rq->nr_sectors << 9;
        !           197:                } else {
        !           198:                        /* group sequential buffers into one large buffer */
        !           199:                        addr = virt_to_bus (bh->b_data);
        !           200:                        size = bh->b_size;
        !           201:                        while ((bh = bh->b_reqnext) != NULL) {
        !           202:                                if ((addr + size) != virt_to_bus (bh->b_data))
        !           203:                                        break;
        !           204:                                size += bh->b_size;
        !           205:                        }
        !           206:                }
        !           207: 
        !           208:                /*
        !           209:                 * Fill in the dma table, without crossing any 64kB boundaries.
        !           210:                 * We assume 16-bit alignment of all blocks.
        !           211:                 */
        !           212:                while (size) {
        !           213:                        if (++count >= PRD_ENTRIES) {
        !           214:                                printk("%s: DMA table too small\n", drive->name);
        !           215:                                return 1; /* revert to PIO for this request */
        !           216:                        } else {
        !           217:                                unsigned long bcount = 0x10000 - (addr & 0xffff);
        !           218:                                if (bcount > size)
        !           219:                                        bcount = size;
        !           220:                                *table++ = addr;
        !           221:                                *table++ = bcount;
        !           222:                                addr += bcount;
        !           223:                                size -= bcount;
        !           224:                        }
        !           225:                }
        !           226:        } while (bh != NULL);
        !           227:        if (count) {
        !           228:                *--table |= 0x80000000; /* set End-Of-Table (EOT) bit */
        !           229:                return 0;
        !           230:        }
        !           231:        printk("%s: empty DMA table?\n", drive->name);
        !           232:        return 1;       /* let the PIO routines handle this weirdness */
        !           233: }
        !           234: 
        !           235: static int config_drive_for_dma (ide_drive_t *drive)
        !           236: {
        !           237:        const char **list;
        !           238: 
        !           239:        struct hd_driveid *id = drive->id;
        !           240:        if (id && (id->capability & 1)) {
        !           241:                /* Enable DMA on any drive that supports mword2 DMA */
        !           242:                if ((id->field_valid & 2) && (id->dma_mword & 0x404) == 0x404) {
        !           243:                        drive->using_dma = 1;
        !           244:                        return 0;               /* DMA enabled */
        !           245:                }
        !           246:                /* Consult the list of known "good" drives */
        !           247:                list = good_dma_drives;
        !           248:                while (*list) {
        !           249:                        if (!strcmp(*list++,id->model)) {
        !           250:                                drive->using_dma = 1;
        !           251:                                return 0;       /* DMA enabled */
        !           252:                        }
        !           253:                }
        !           254:        }
        !           255:        return 1;       /* DMA not enabled */
        !           256: }
        !           257: 
        !           258: /*
        !           259:  * triton_dmaproc() initiates/aborts DMA read/write operations on a drive.
        !           260:  *
        !           261:  * The caller is assumed to have selected the drive and programmed the drive's
        !           262:  * sector address using CHS or LBA.  All that remains is to prepare for DMA
        !           263:  * and then issue the actual read/write DMA/PIO command to the drive.
        !           264:  *
        !           265:  * For ATAPI devices, we just prepare for DMA and return. The caller should
        !           266:  * then issue the packet command to the drive and call us again with
        !           267:  * ide_dma_begin afterwards.
        !           268:  *
        !           269:  * Returns 0 if all went well.
        !           270:  * Returns 1 if DMA read/write could not be started, in which case
        !           271:  * the caller should revert to PIO for the current request.
        !           272:  */
        !           273: static int triton_dmaproc (ide_dma_action_t func, ide_drive_t *drive)
        !           274: {
        !           275:        unsigned long dma_base = HWIF(drive)->dma_base;
        !           276:        unsigned int reading = (1 << 3);
        !           277: 
        !           278:        switch (func) {
        !           279:                case ide_dma_abort:
        !           280:                        outb(inb(dma_base)&~1, dma_base);       /* stop DMA */
        !           281:                        return 0;
        !           282:                case ide_dma_check:
        !           283:                        return config_drive_for_dma (drive);
        !           284:                case ide_dma_write:
        !           285:                        reading = 0;
        !           286:                case ide_dma_read:
        !           287:                        break;
        !           288:                case ide_dma_status_bad:
        !           289:                        return ((inb(dma_base+2) & 7) != 4);    /* verify good DMA status */
        !           290:                case ide_dma_transferred:
        !           291: #if 0
        !           292:                        return (number of bytes actually transferred);
        !           293: #else
        !           294:                        return (0);
        !           295: #endif
        !           296:                case ide_dma_begin:
        !           297:                        outb(inb(dma_base)|1, dma_base);        /* begin DMA */
        !           298:                        return 0;
        !           299:                default:
        !           300:                        printk("triton_dmaproc: unsupported func: %d\n", func);
        !           301:                        return 1;
        !           302:        }
        !           303:        if (build_dmatable (drive))
        !           304:                return 1;
        !           305:        outl(virt_to_bus (HWIF(drive)->dmatable), dma_base + 4); /* PRD table */
        !           306:        outb(reading, dma_base);                        /* specify r/w */
        !           307:        outb(0x26, dma_base+2);                         /* clear status bits */
        !           308: #ifdef CONFIG_BLK_DEV_IDEATAPI
        !           309:        if (drive->media != ide_disk)
        !           310:                return 0;
        !           311: #endif /* CONFIG_BLK_DEV_IDEATAPI */   
        !           312:        ide_set_handler(drive, &dma_intr, WAIT_CMD);    /* issue cmd to drive */
        !           313:        OUT_BYTE(reading ? WIN_READDMA : WIN_WRITEDMA, IDE_COMMAND_REG);
        !           314:        outb(inb(dma_base)|1, dma_base);                /* begin DMA */
        !           315:        return 0;
        !           316: }
        !           317: 
        !           318: /*
        !           319:  * print_triton_drive_flags() displays the currently programmed options
        !           320:  * in the Triton chipset for a given drive.
        !           321:  *
        !           322:  *     If fastDMA  is "no", then slow ISA timings are used for DMA data xfers.
        !           323:  *     If fastPIO  is "no", then slow ISA timings are used for PIO data xfers.
        !           324:  *     If IORDY    is "no", then IORDY is assumed to always be asserted.
        !           325:  *     If PreFetch is "no", then data pre-fetch/post are not used.
        !           326:  *
        !           327:  * When "fastPIO" and/or "fastDMA" are "yes", then faster PCI timings and
        !           328:  * back-to-back 16-bit data transfers are enabled, using the sample_CLKs
        !           329:  * and recovery_CLKs (PCI clock cycles) timing parameters for that interface.
        !           330:  */
        !           331: static void print_triton_drive_flags (unsigned int unit, byte flags)
        !           332: {
        !           333:        printk("         %s ", unit ? "slave :" : "master:");
        !           334:        printk( "fastDMA=%s",   (flags&9)       ? "on " : "off");
        !           335:        printk(" PreFetch=%s",  (flags&4)       ? "on " : "off");
        !           336:        printk(" IORDY=%s",     (flags&2)       ? "on " : "off");
        !           337:        printk(" fastPIO=%s\n", ((flags&9)==1)  ? "on " : "off");
        !           338: }
        !           339: 
        !           340: static void init_triton_dma (ide_hwif_t *hwif, unsigned short base)
        !           341: {
        !           342:        static unsigned long dmatable = 0;
        !           343: 
        !           344: #if 0
        !           345:        printk("    %s: BusMaster DMA at 0x%04x-0x%04x", hwif->name, base, base+7);
        !           346: #endif
        !           347:        if (check_region(base, 8)) {
        !           348: #if 0
        !           349:                printk(" -- ERROR, PORTS ALREADY IN USE");
        !           350: #endif
        !           351:        } else {
        !           352:                request_region(base, 8, "triton DMA");
        !           353:                hwif->dma_base = base;
        !           354:                if (!dmatable) {
        !           355:                        /*
        !           356:                         * Since we know we are on a PCI bus, we could
        !           357:                         * actually use __get_free_pages() here instead
        !           358:                         * of __get_dma_pages() -- no ISA limitations.
        !           359:                         */
        !           360:                        dmatable = __get_dma_pages(GFP_KERNEL, 0);
        !           361:                }
        !           362:                if (dmatable) {
        !           363:                        hwif->dmatable = (unsigned long *) dmatable;
        !           364:                        dmatable += (PRD_ENTRIES * PRD_BYTES);
        !           365:                        outl(virt_to_bus(hwif->dmatable), base + 4);
        !           366:                        hwif->dmaproc  = &triton_dmaproc;
        !           367:                }
        !           368:        }
        !           369: #if 0
        !           370:        printk("\n");
        !           371: #endif
        !           372: }
        !           373: 
        !           374: /*
        !           375:  * calc_mode() returns the ATA PIO mode number, based on the number
        !           376:  * of cycle clks passed in.  Assumes 33Mhz bus operation (30ns per clk).
        !           377:  */
        !           378: byte calc_mode (byte clks)
        !           379: {
        !           380:        if (clks == 3)  return 5;
        !           381:        if (clks == 4)  return 4;
        !           382:        if (clks <  6)  return 3;
        !           383:        if (clks <  8)  return 2;
        !           384:        if (clks < 13)  return 1;
        !           385:        return 0;
        !           386: }
        !           387: 
        !           388: /*
        !           389:  * ide_init_triton() prepares the IDE driver for DMA operation.
        !           390:  * This routine is called once, from ide.c during driver initialization,
        !           391:  * for each triton chipset which is found (unlikely to be more than one).
        !           392:  */
        !           393: void ide_init_triton (byte bus, byte fn)
        !           394: {
        !           395:        int rc = 0, h;
        !           396:        int dma_enabled = 0;
        !           397:        unsigned short bmiba, pcicmd;
        !           398:        unsigned int timings;
        !           399: 
        !           400:        printk("ide: Triton BM-IDE on PCI bus %d function %d\n", bus, fn);
        !           401:        /*
        !           402:         * See if IDE and BM-DMA features are enabled:
        !           403:         */
        !           404:        if ((rc = pcibios_read_config_word(bus, fn, 0x04, &pcicmd)))
        !           405:                goto quit;
        !           406:        if ((pcicmd & 1) == 0)  {
        !           407:                printk("ide: Triton IDE ports are not enabled\n");
        !           408:                goto quit;
        !           409:        }
        !           410:        if ((pcicmd & 4) == 0) {
        !           411:                printk("ide: Triton BM-DMA feature is not enabled -- upgrade your BIOS\n");
        !           412:        } else {
        !           413:                /*
        !           414:                 * Get the bmiba base address
        !           415:                 */
        !           416:                if ((rc = pcibios_read_config_word(bus, fn, 0x20, &bmiba)))
        !           417:                        goto quit;
        !           418:                bmiba &= 0xfff0;        /* extract port base address */
        !           419:                dma_enabled = 1;
        !           420:        }
        !           421: 
        !           422:        /*
        !           423:         * See if ide port(s) are enabled
        !           424:         */
        !           425:        if ((rc = pcibios_read_config_dword(bus, fn, 0x40, &timings)))
        !           426:                goto quit;
        !           427:        if (!(timings & 0x80008000)) {
        !           428:                printk("ide: neither Triton IDE port is enabled\n");
        !           429:                goto quit;
        !           430:        }
        !           431: 
        !           432:        /*
        !           433:         * Save the dma_base port addr for each interface
        !           434:         */
        !           435:        for (h = 0; h < MAX_HWIFS; ++h) {
        !           436:                byte s_clks, r_clks;
        !           437:                ide_hwif_t *hwif = &ide_hwifs[h];
        !           438:                unsigned short time;
        !           439:                if (hwif->io_base == 0x1f0) {
        !           440:                        time = timings & 0xffff;
        !           441:                        if ((timings & 0x8000) == 0)    /* interface enabled? */
        !           442:                                continue;
        !           443:                        hwif->chipset = ide_triton;
        !           444:                        if (dma_enabled)
        !           445:                                init_triton_dma(hwif, bmiba);
        !           446:                } else if (hwif->io_base == 0x170) {
        !           447:                        time = timings >> 16;
        !           448:                        if ((timings & 0x8000) == 0)    /* interface enabled? */
        !           449:                                continue;
        !           450:                        hwif->chipset = ide_triton;
        !           451:                        if (dma_enabled)
        !           452:                                init_triton_dma(hwif, bmiba + 8);
        !           453:                } else
        !           454:                        continue;
        !           455:                s_clks = ((~time >> 12) & 3) + 2;
        !           456:                r_clks = ((~time >>  8) & 3) + 1;
        !           457: #if 0
        !           458:                printk("    %s timing: (0x%04x) sample_CLKs=%d, recovery_CLKs=%d (PIO mode%d)\n",
        !           459:                 hwif->name, time, s_clks, r_clks, calc_mode(s_clks+r_clks));
        !           460:                print_triton_drive_flags (0, time & 0xf);
        !           461:                print_triton_drive_flags (1, (time >> 4) & 0xf);
        !           462: #endif
        !           463:        }
        !           464: 
        !           465: quit: if (rc) printk("ide: pcibios access failed - %s\n", pcibios_strerror(rc));
        !           466: }
        !           467: 

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