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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 - bon@elektron.ikp.physik.th-darmstadt.de)
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 * Maxtor 71260AT (1204Meg w/256kB buffer), DMA mword0/sword2, PIO mode3.
89 * - works with DMA, giving 3-4MB/sec performance, about the same as mode3.
90 *
91 * If you have any drive models to add, email your results to: mlord@pobox.com
92 * Keep an eye on /var/adm/messages for "DMA disabled" messages.
93 *
94 * Some people have reported trouble with Intel Zappa motherboards.
95 * This can be fixed by upgrading the AMI BIOS to version 1.00.04.BS0,
96 * available from ftp://ftp.intel.com/pub/bios/10004bs0.exe
97 * (thanks to Glen Morrell <glen@spin.Stanford.edu> for researching this).
98 *
99 * And, yes, Intel Zappa boards really *do* use the Triton IDE ports.
100 */
101 #include <linux/config.h>
102 #include <linux/types.h>
103 #include <linux/kernel.h>
104 #include <linux/timer.h>
105 #include <linux/mm.h>
106 #include <linux/ioport.h>
107 #include <linux/interrupt.h>
108 #include <linux/blkdev.h>
109 #include <linux/hdreg.h>
110 #include <linux/pci.h>
111 #include <linux/bios32.h>
112
113 #include <asm/io.h>
114 #include <asm/dma.h>
115
116 #include "ide.h"
117
118 /*
119 * good_dma_drives() lists the model names (from "hdparm -i")
120 * of drives which do not support mword2 DMA but which are
121 * known to work fine with this interface under Linux.
122 */
123 const char *good_dma_drives[] = {"Micropolis 2112A",
124 "Maxtor 71260 AT",
125 "CONNER CTMA 4000"};
126
127 /*
128 * Our Physical Region Descriptor (PRD) table should be large enough
129 * to handle the biggest I/O request we are likely to see. Since requests
130 * can have no more than 256 sectors, and since the typical blocksize is
131 * two sectors, we could get by with a limit of 128 entries here for the
132 * usual worst case. Most requests seem to include some contiguous blocks,
133 * further reducing the number of table entries required.
134 *
135 * The driver reverts to PIO mode for individual requests that exceed
136 * this limit (possible with 512 byte blocksizes, eg. MSDOS f/s), so handling
137 * 100% of all crazy scenarios here is not necessary.
138 *
139 * As it turns out though, we must allocate a full 4KB page for this,
140 * so the two PRD tables (ide0 & ide1) will each get half of that,
141 * allowing each to have about 256 entries (8 bytes each) from this.
142 */
143 #define PRD_BYTES 8
144 #define PRD_ENTRIES (PAGE_SIZE / (2 * PRD_BYTES))
145
146 /*
147 * dma_intr() is the handler for disk read/write DMA interrupts
148 */
149 static void dma_intr (ide_drive_t *drive)
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150 {
151 byte stat, dma_stat;
152 int i;
153 struct request *rq = HWGROUP(drive)->rq;
154 unsigned short dma_base = HWIF(drive)->dma_base;
155
156 dma_stat = inb(dma_base+2); /* get DMA status */
157 outb(inb(dma_base)&~1, dma_base); /* stop DMA operation */
158 stat = GET_STAT(); /* get drive status */
159 if (OK_STAT(stat,DRIVE_READY,drive->bad_wstat|DRQ_STAT)) {
160 if ((dma_stat & 7) == 4) { /* verify good DMA status */
161 rq = HWGROUP(drive)->rq;
162 for (i = rq->nr_sectors; i > 0;) {
163 i -= rq->current_nr_sectors;
164 ide_end_request(1, HWGROUP(drive));
165 }
166 return;
167 }
168 printk("%s: bad DMA status: 0x%02x\n", drive->name, dma_stat);
169 }
170 sti();
171 ide_error(drive, "dma_intr", stat);
172 }
173
174 /*
175 * build_dmatable() prepares a dma request.
176 * Returns 0 if all went okay, returns 1 otherwise.
177 */
178 static int build_dmatable (ide_drive_t *drive)
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179 {
180 struct request *rq = HWGROUP(drive)->rq;
181 struct buffer_head *bh = rq->bh;
182 unsigned long size, addr, *table = HWIF(drive)->dmatable;
183 unsigned int count = 0;
184
185 do {
186 /*
187 * Determine addr and size of next buffer area. We assume that
188 * individual virtual buffers are always composed linearly in
189 * physical memory. For example, we assume that any 8kB buffer
190 * is always composed of two adjacent physical 4kB pages rather
191 * than two possibly non-adjacent physical 4kB pages.
192 */
193 if (bh == NULL) { /* paging and tape requests have (rq->bh == NULL) */
194 addr = virt_to_bus (rq->buffer);
195 #ifdef CONFIG_BLK_DEV_IDETAPE
196 if (drive->media == ide_tape)
197 size = drive->tape.pc->request_transfer;
198 else
199 #endif /* CONFIG_BLK_DEV_IDETAPE */
200 size = rq->nr_sectors << 9;
201 } else {
202 /* group sequential buffers into one large buffer */
203 addr = virt_to_bus (bh->b_data);
204 size = bh->b_size;
205 while ((bh = bh->b_reqnext) != NULL) {
206 if ((addr + size) != virt_to_bus (bh->b_data))
207 break;
208 size += bh->b_size;
209 }
210 }
211
212 /*
213 * Fill in the dma table, without crossing any 64kB boundaries.
214 * We assume 16-bit alignment of all blocks.
215 */
216 while (size) {
217 if (++count >= PRD_ENTRIES) {
218 printk("%s: DMA table too small\n", drive->name);
219 return 1; /* revert to PIO for this request */
220 } else {
221 unsigned long bcount = 0x10000 - (addr & 0xffff);
222 if (bcount > size)
223 bcount = size;
224 *table++ = addr;
225 *table++ = bcount;
226 addr += bcount;
227 size -= bcount;
228 }
229 }
230 } while (bh != NULL);
231 if (count) {
232 *--table |= 0x80000000; /* set End-Of-Table (EOT) bit */
233 return 0;
234 }
235 printk("%s: empty DMA table?\n", drive->name);
236 return 1; /* let the PIO routines handle this weirdness */
237 }
238
239 static int config_drive_for_dma (ide_drive_t *drive)
/* */
240 {
241 const char **list;
242
243 struct hd_driveid *id = drive->id;
244 if (id && (id->capability & 1)) {
245 /* Enable DMA on any drive that supports mword2 DMA */
246 if ((id->field_valid & 2) && (id->dma_mword & 0x404) == 0x404) {
247 drive->using_dma = 1;
248 return 0; /* DMA enabled */
249 }
250 /* Consult the list of known "good" drives */
251 list = good_dma_drives;
252 while (*list) {
253 if (!strcmp(*list++,id->model)) {
254 drive->using_dma = 1;
255 return 0; /* DMA enabled */
256 }
257 }
258 }
259 return 1; /* DMA not enabled */
260 }
261
262 /*
263 * triton_dmaproc() initiates/aborts DMA read/write operations on a drive.
264 *
265 * The caller is assumed to have selected the drive and programmed the drive's
266 * sector address using CHS or LBA. All that remains is to prepare for DMA
267 * and then issue the actual read/write DMA/PIO command to the drive.
268 *
269 * For ATAPI devices, we just prepare for DMA and return. The caller should
270 * then issue the packet command to the drive and call us again with
271 * ide_dma_begin afterwards.
272 *
273 * Returns 0 if all went well.
274 * Returns 1 if DMA read/write could not be started, in which case
275 * the caller should revert to PIO for the current request.
276 */
277 static int triton_dmaproc (ide_dma_action_t func, ide_drive_t *drive)
/* */
278 {
279 unsigned long dma_base = HWIF(drive)->dma_base;
280 unsigned int reading = (1 << 3);
281
282 switch (func) {
283 case ide_dma_abort:
284 outb(inb(dma_base)&~1, dma_base); /* stop DMA */
285 return 0;
286 case ide_dma_check:
287 return config_drive_for_dma (drive);
288 case ide_dma_write:
289 reading = 0;
290 case ide_dma_read:
291 break;
292 case ide_dma_status_bad:
293 return ((inb(dma_base+2) & 7) != 4); /* verify good DMA status */
294 case ide_dma_transferred:
295 #if 0
296 return (number of bytes actually transferred);
297 #else
298 return (0);
299 #endif
300 case ide_dma_begin:
301 outb(inb(dma_base)|1, dma_base); /* begin DMA */
302 return 0;
303 default:
304 printk("triton_dmaproc: unsupported func: %d\n", func);
305 return 1;
306 }
307 if (build_dmatable (drive))
308 return 1;
309 outl(virt_to_bus (HWIF(drive)->dmatable), dma_base + 4); /* PRD table */
310 outb(reading, dma_base); /* specify r/w */
311 outb(0x26, dma_base+2); /* clear status bits */
312 #ifdef CONFIG_BLK_DEV_IDEATAPI
313 if (drive->media != ide_disk)
314 return 0;
315 #endif /* CONFIG_BLK_DEV_IDEATAPI */
316 ide_set_handler(drive, &dma_intr, WAIT_CMD); /* issue cmd to drive */
317 OUT_BYTE(reading ? WIN_READDMA : WIN_WRITEDMA, IDE_COMMAND_REG);
318 outb(inb(dma_base)|1, dma_base); /* begin DMA */
319 return 0;
320 }
321
322 /*
323 * print_triton_drive_flags() displays the currently programmed options
324 * in the Triton chipset for a given drive.
325 *
326 * If fastDMA is "no", then slow ISA timings are used for DMA data xfers.
327 * If fastPIO is "no", then slow ISA timings are used for PIO data xfers.
328 * If IORDY is "no", then IORDY is assumed to always be asserted.
329 * If PreFetch is "no", then data pre-fetch/post are not used.
330 *
331 * When "fastPIO" and/or "fastDMA" are "yes", then faster PCI timings and
332 * back-to-back 16-bit data transfers are enabled, using the sample_CLKs
333 * and recovery_CLKs (PCI clock cycles) timing parameters for that interface.
334 */
335 static void print_triton_drive_flags (unsigned int unit, byte flags)
/* */
336 {
337 printk(" %s ", unit ? "slave :" : "master:");
338 printk( "fastDMA=%s", (flags&9) ? "on " : "off");
339 printk(" PreFetch=%s", (flags&4) ? "on " : "off");
340 printk(" IORDY=%s", (flags&2) ? "on " : "off");
341 printk(" fastPIO=%s\n", ((flags&9)==1) ? "on " : "off");
342 }
343
344 static void init_triton_dma (ide_hwif_t *hwif, unsigned short base)
/* */
345 {
346 static unsigned long dmatable = 0;
347
348 printk(" %s: BusMaster DMA at 0x%04x-0x%04x", hwif->name, base, base+7);
349 if (check_region(base, 8)) {
350 printk(" -- ERROR, PORTS ALREADY IN USE");
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 printk("\n");
370 }
371
372 /*
373 * calc_mode() returns the ATA PIO mode number, based on the number
374 * of cycle clks passed in. Assumes 33Mhz bus operation (30ns per clk).
375 */
376 byte calc_mode (byte clks)
/* */
377 {
378 if (clks == 3) return 5;
379 if (clks == 4) return 4;
380 if (clks < 6) return 3;
381 if (clks < 8) return 2;
382 if (clks < 13) return 1;
383 return 0;
384 }
385
386 /*
387 * ide_init_triton() prepares the IDE driver for DMA operation.
388 * This routine is called once, from ide.c during driver initialization,
389 * for each triton chipset which is found (unlikely to be more than one).
390 */
391 void ide_init_triton (byte bus, byte fn)
/* ![[last]](../icons/n_last.png)
*/
392 {
393 int rc = 0, h;
394 int dma_enabled = 0;
395 unsigned short bmiba, pcicmd;
396 unsigned int timings;
397
398 printk("ide: Triton BM-IDE on PCI bus %d function %d\n", bus, fn);
399 /*
400 * See if IDE and BM-DMA features are enabled:
401 */
402 if ((rc = pcibios_read_config_word(bus, fn, 0x04, &pcicmd)))
403 goto quit;
404 if ((pcicmd & 1) == 0) {
405 printk("ide: Triton IDE ports are not enabled\n");
406 goto quit;
407 }
408 if ((pcicmd & 4) == 0) {
409 printk("ide: Triton BM-DMA feature is not enabled -- upgrade your BIOS\n");
410 } else {
411 /*
412 * Get the bmiba base address
413 */
414 if ((rc = pcibios_read_config_word(bus, fn, 0x20, &bmiba)))
415 goto quit;
416 bmiba &= 0xfff0; /* extract port base address */
417 dma_enabled = 1;
418 }
419
420 /*
421 * See if ide port(s) are enabled
422 */
423 if ((rc = pcibios_read_config_dword(bus, fn, 0x40, &timings)))
424 goto quit;
425 if (!(timings & 0x80008000)) {
426 printk("ide: neither Triton IDE port is enabled\n");
427 goto quit;
428 }
429
430 /*
431 * Save the dma_base port addr for each interface
432 */
433 for (h = 0; h < MAX_HWIFS; ++h) {
434 byte s_clks, r_clks;
435 ide_hwif_t *hwif = &ide_hwifs[h];
436 unsigned short time;
437 if (hwif->io_base == 0x1f0) {
438 time = timings & 0xffff;
439 if ((timings & 0x8000) == 0) /* interface enabled? */
440 continue;
441 hwif->chipset = ide_triton;
442 if (dma_enabled)
443 init_triton_dma(hwif, bmiba);
444 } else if (hwif->io_base == 0x170) {
445 time = timings >> 16;
446 if ((timings & 0x8000) == 0) /* interface enabled? */
447 continue;
448 hwif->chipset = ide_triton;
449 if (dma_enabled)
450 init_triton_dma(hwif, bmiba + 8);
451 } else
452 continue;
453 s_clks = ((~time >> 12) & 3) + 2;
454 r_clks = ((~time >> 8) & 3) + 1;
455 printk(" %s timing: (0x%04x) sample_CLKs=%d, recovery_CLKs=%d (PIO mode%d)\n",
456 hwif->name, time, s_clks, r_clks, calc_mode(s_clks+r_clks));
457 print_triton_drive_flags (0, time & 0xf);
458 print_triton_drive_flags (1, (time >> 4) & 0xf);
459 }
460
461 quit: if (rc) printk("ide: pcibios access failed - %s\n", pcibios_strerror(rc));
462 }
463
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*/