patch-1.3.21 linux/drivers/block/triton.c
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- Lines: 353
- Date:
Mon Aug 28 09:19:32 1995
- Orig file:
v1.3.20/linux/drivers/block/triton.c
- Orig date:
Thu Jan 1 02:00:00 1970
diff -u --recursive --new-file v1.3.20/linux/drivers/block/triton.c linux/drivers/block/triton.c
@@ -0,0 +1,352 @@
+/*
+ * linux/drivers/block/triton.c Version 1.00 Aug 26, 1995
+ *
+ * Copyright (c) 1995 Mark Lord
+ * May be copied or modified under the terms of the GNU General Public License
+ */
+
+/*
+ * This module provides support for the Bus Master IDE DMA function
+ * of the Intel PCI Triton chipset (82371FB).
+ *
+ * DMA is currently supported only for hard disk drives (not cdroms).
+ *
+ * Support for cdroms will likely be added at a later date,
+ * after broader experience has been obtained with hard disks.
+ *
+ * Up to four drives may be enabled for DMA, and the Triton chipset will
+ * (hopefully) arbitrate the PCI bus among them. Note that the 82371FB chip
+ * provides a single "line buffer" for the BM IDE function, so performance of
+ * multiple (two) drives doing DMA simultaneously will suffer somewhat,
+ * as they contest for that resource bottleneck. This is handled transparently
+ * inside the 82371FB chip.
+ *
+ * By default, DMA support is prepared for use, but is currently enabled only
+ * for drives which support multi-word DMA mode2 (mword2), or which are
+ * recognized as "good" (see table below). Drives with only mode0 or mode1
+ * (single or multi) DMA should also work with this chipset/driver (eg. MC2112A)
+ * but are not enabled by default. Use "hdparm -i" to view supported modes
+ * for a given drive.
+ *
+ * The hdparm-2.4 (or later) utility can be used for manually enabling/disabling
+ * DMA support, but must be (re-)compiled against this kernel version or later.
+ *
+ * To enable DMA, use "hdparm -d1 /dev/hd?" on a per-drive basis after booting.
+ * If problems arise, ide.c will disable DMA operation after a few retries.
+ * This error recovery mechanism works and has been extremely well exercised.
+ *
+ * IDE drives, depending on their vintage, may support several different modes
+ * of DMA operation. The boot-time modes are indicated with a "*" in
+ * the "hdparm -i" listing, and can be changed with *knowledgeable* use of
+ * the "hdparm -X" feature. There is seldom a need to do this, as drives
+ * normally power-up with their "best" PIO/DMA modes enabled.
+ *
+ * Testing was done with an ASUS P55TP4XE/100 system and the following drives:
+ *
+ * Quantum Fireball 1080A (1Gig w/83kB buffer), DMA mode2, PIO mode4.
+ * - DMA mode2 works fine (7.4MB/sec), despite the tiny on-drive buffer.
+ * - This drive also does PIO mode4, slightly slower than DMA mode2.
+ *
+ * Micropolis MC2112A (1Gig w/512kB buffer), drive pre-dates EIDE, ATA2.
+ * - DMA works fine (2.2MB/sec), probably due to the large on-drive buffer.
+ * - This older drive can also be tweaked for fastPIO (3,7MB/sec) by using
+ * maximum clock settings (5,4) and setting all flags except prefetch.
+ *
+ * Western Digital AC31000H (1Gig w/128kB buffer), DMA mode1, PIO mode3.
+ * - DMA does not work reliably. The drive appears to be somewhat tardy
+ * in deasserting DMARQ at the end of a sector. This is evident in
+ * the observation that WRITEs work most of the time, depending on
+ * cache-buffer occupancy, but multi-sector reads seldom work.
+ *
+ * Drives like the AC31000H could likely be made to work if all DMA were done
+ * one sector at a time, but that would likely negate any advantage over PIO.
+ *
+ * If you have any drive models add, email your results to: [email protected]
+ * Keep an eye on your /var/adm/messages for "DMA disabled" messages.
+ */
+#define _TRITON_C
+#include <linux/config.h>
+#ifndef CONFIG_BLK_DEV_TRITON
+#define CONFIG_BLK_DEV_TRITON y
+#endif
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/ioport.h>
+#include <linux/interrupt.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.h>
+#include <linux/pci.h>
+#include <linux/bios32.h>
+#include <asm/io.h>
+
+#include "ide.h"
+
+/*
+ * good_dma_drives() lists the model names (from "hdparm -i")
+ * of drives which do not support mword2 DMA but which are
+ * known to work fine with this interface under Linux.
+ */
+const char *good_dma_drives[] = {"Micropolis 2112A"};
+
+/*
+ * Our Physical Region Descriptor (PRD) table should be large enough
+ * to handle the biggest I/O request we are likely to see. Since requests
+ * can have no more than 256 sectors, and since the typical blocksize is
+ * two sectors, we can get by with a limit of 128 entries here for the
+ * usual worst case. Most requests seem to include some contiguous blocks,
+ * further reducing the number of table entries required.
+ *
+ * Note that the driver reverts to PIO mode for individual requests that exceed
+ * this limit (possible with 512 byte blocksizes, eg. MSDOS f/s), so handling
+ * 100% of all crazy scenarios here is not necessary.
+ */
+#define PRD_ENTRIES 128 /* max memory area count per DMA */
+
+/*
+ * dma_intr() is the handler for disk read/write DMA interrupts
+ */
+static void dma_intr (ide_drive_t *drive)
+{
+ byte stat, dma_stat;
+ int i;
+ struct request *rq = HWGROUP(drive)->rq;
+ unsigned short dma_base = HWIF(drive)->dma_base;
+
+ dma_stat = inb(dma_base+2); /* get DMA status */
+ outb(inb(dma_base)&~1, dma_base); /* stop DMA operation */
+ stat = GET_STAT();
+ if (OK_STAT(stat,DRIVE_READY,drive->bad_wstat|DRQ_STAT)) {
+ if ((dma_stat & 7) == 4) { /* verify good DMA status */
+ rq = HWGROUP(drive)->rq;
+ for (i = rq->nr_sectors; i > 0;) {
+ i -= rq->current_nr_sectors;
+ ide_end_request(1, HWGROUP(drive));
+ }
+ IDE_DO_REQUEST;
+ return;
+ }
+ printk("%s: bad DMA status: 0x%02x\n", drive->name, dma_stat);
+ }
+ sti();
+ if (!ide_error(drive, "dma_intr", stat))
+ IDE_DO_REQUEST;
+}
+
+/*
+ * build_dmatable() prepares a dma request.
+ * Returns 0 if all went okay, returns 1 otherwise.
+ */
+static int build_dmatable (ide_drive_t *drive)
+{
+ struct request *rq = HWGROUP(drive)->rq;
+ struct buffer_head *bh = rq->bh;
+ unsigned long size, addr, *table = HWIF(drive)->dmatable;
+ unsigned int count = 0;
+
+ do {
+ /*
+ * Determine addr and size of next buffer area. We assume that
+ * individual virtual buffers are always composed linearly in
+ * physical memory. For example, we assume that any 8kB buffer
+ * is always composed of two adjacent physical 4kB pages rather
+ * than two possibly non-adjacent physical 4kB pages.
+ */
+ if (bh == NULL) { /* paging requests have (rq->bh == NULL) */
+ addr = virt_to_bus (rq->buffer);
+ size = rq->nr_sectors << 9;
+ } else {
+ /* group sequential buffers into one large buffer */
+ addr = virt_to_bus (bh->b_data);
+ size = bh->b_size;
+ while ((bh = bh->b_reqnext) != NULL) {
+ if ((addr + size) != virt_to_bus (bh->b_data))
+ break;
+ size += bh->b_size;
+ }
+ }
+
+ /*
+ * Fill in the dma table, without crossing any 64kB boundaries.
+ * We assume 16-bit alignment of all blocks.
+ */
+ while (size) {
+ if (++count >= PRD_ENTRIES) {
+ printk("%s: DMA table too small\n", drive->name);
+ return 1; /* revert to PIO for this request */
+ } else {
+ unsigned long bcount = 0x10000 - (addr & 0xffff);
+ if (bcount > size)
+ bcount = size;
+ *table++ = addr;
+ *table++ = bcount;
+ addr += bcount;
+ size -= bcount;
+ }
+ }
+ } while (bh != NULL);
+ if (count) {
+ *--table |= 0x80000000; /* set End-Of-Table (EOT) bit */
+ return 0;
+ }
+ printk("%s: empty DMA table?\n", drive->name);
+ return 1; /* let the PIO routines handle this weirdness */
+}
+
+/*
+ * triton_dmaproc() initiates/aborts DMA read/write operations on a drive.
+ *
+ * The caller is assumed to have selected the drive and programmed the drive's
+ * sector address using CHS or LBA. All that remains is to prepare for DMA
+ * and then issue the actual read/write DMA/PIO command to the drive.
+ *
+ * Returns 0 if all went well.
+ * Returns 1 if DMA read/write could not be started, in which case
+ * the caller should revert to PIO for the current request.
+ */
+static int triton_dmaproc (ide_dma_action_t func, ide_drive_t *drive)
+{
+ const char **list;
+ unsigned long dma_base = HWIF(drive)->dma_base;
+
+ if (func == ide_dma_abort) {
+ outb(inb(dma_base)&~1, dma_base); /* stop DMA */
+ return 0;
+ }
+ if (func == ide_dma_check) {
+ struct hd_driveid *id = drive->id;
+ if (id && (id->capability & 1)) {
+ /* Enable DMA on any drive that supports mword2 DMA */
+ if ((id->field_valid & 2) && (id->dma_mword & 0x404) == 0x404) {
+ drive->using_dma = 1;
+ return 0; /* DMA enabled */
+ }
+ /* Consult the list of known "good" drives */
+ list = good_dma_drives;
+ while (*list) {
+ if (!strcmp(*list++,id->model)) {
+ drive->using_dma = 1;
+ return 0; /* DMA enabled */
+ }
+ }
+ }
+ return 1; /* DMA not enabled */
+ }
+ if (build_dmatable (drive))
+ return 1;
+ outl(virt_to_bus (HWIF(drive)->dmatable), dma_base + 4); /* PRD table */
+ outb((!func) << 3, dma_base); /* specify r/w */
+ outb(0x26, dma_base+2); /* clear status bits */
+ ide_set_handler (drive, &dma_intr); /* issue cmd to drive */
+ OUT_BYTE(func ? WIN_WRITEDMA : WIN_READDMA, IDE_COMMAND_REG);
+ outb(inb(dma_base)|1, dma_base); /* begin DMA */
+ return 0;
+}
+
+/*
+ * print_triton_drive_flags() displays the currently programmed options
+ * in the Triton chipset for a given drive.
+ *
+ * If fastDMA is "no", then slow ISA timings are used for DMA data xfers.
+ * If fastPIO is "no", then slow ISA timings are used for PIO data xfers.
+ * If IORDY is "no", then IORDY is assumed to always be asserted.
+ * If PreFetch is "no", then data pre-fetch/post are not used.
+ *
+ * When "fastPIO" and/or "fastDMA" are "yes", then faster PCI timings and
+ * back-to-back 16-bit data transfers are enabled, using the sample_CLKs
+ * and recovery_CLKs (PCI clock cycles) timing parameters for that interface.
+ */
+static void print_triton_drive_flags (unsigned int unit, byte flags)
+{
+ printk(" %s ", unit ? "slave :" : "master:");
+ printk( "fastDMA=%s", (flags&9) ? "on " : "off");
+ printk(" PreFetch=%s", (flags&4) ? "on " : "off");
+ printk(" IORDY=%s", (flags&2) ? "on " : "off");
+ printk(" fastPIO=%s\n", ((flags&9)==1) ? "on " : "off");
+}
+
+/*
+ * ide_init_triton() uses the PCI BIOS to scan for a Triton i82371FB chip,
+ * and prepares the IDE driver for DMA operation if one is found.
+ * This routine is called from ide.c during driver initialization.
+ */
+void ide_init_triton (ide_hwif_t hwifs[])
+{
+ int rc = 0, h;
+ unsigned short bmiba, pcicmd;
+ unsigned int timings;
+ unsigned char bus, fn;
+
+ if (pcibios_find_device (PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82371, 0, &bus, &fn))
+ goto quit;
+ ++fn; /* IDE is second function on this chip */
+
+ /*
+ * See if IDE and BM-DMA features are enabled:
+ */
+ if ((rc = pcibios_read_config_word(bus, fn, 0x04, &pcicmd)))
+ goto quit;
+ if ((pcicmd & 5) != 5) {
+ if ((pcicmd & 1) == 0)
+ printk("ide: Triton IDE ports are not enabled\n");
+ else
+ printk("ide: Triton BM-DMA feature is not enabled\n");
+ goto quit;
+ }
+#if 0
+ (void) pcibios_write_config_word(bus, fn, 0x42, 0x8037); /* for my MC2112A */
+#endif
+ /*
+ * See if ide port(s) are enabled
+ */
+ if ((rc = pcibios_read_config_dword(bus, fn, 0x40, &timings)))
+ goto quit;
+ if (!(timings & 0x80008000)) {
+ printk("ide: Triton IDE ports are not enabled\n");
+ goto quit;
+ }
+ printk("ide: Triton BM-IDE on PCI bus %d function %d\n", bus, fn);
+
+ /*
+ * Get the bmiba base address
+ */
+ if ((rc = pcibios_read_config_word(bus, fn, 0x20, &bmiba)))
+ goto quit;
+ bmiba &= 0xfff0; /* extract port base address */
+
+ /*
+ * Save the dma_base port addr for each interface
+ */
+ for (h = 0; h < MAX_HWIFS; ++h) {
+ ide_hwif_t *hwif = &hwifs[h];
+ unsigned short base, time;
+ if (hwif->io_base == 0x1f0 && (timings & 0x8000)) {
+ time = timings & 0xffff;
+ base = bmiba;
+ } else if (hwif->io_base == 0x170 && (timings & 0x80000000)) {
+ time = timings >> 16;
+ base = bmiba + 8;
+ } else
+ continue;
+ printk(" %s: BusMaster DMA at 0x%04x-0x%04x", hwif->name, base, base+5);
+ if (check_region(base, 6)) {
+ printk(" -- ERROR, PORTS ALREADY IN USE");
+ } else {
+ unsigned long *table;
+ request_region(base, 8, hwif->name);
+ hwif->dma_base = base;
+ table = ide_alloc(2 * PRD_ENTRIES * sizeof(long), 4096);
+ hwif->dmatable = table;
+ outl((unsigned long) table, base + 4);
+ hwif->dmaproc = &triton_dmaproc;
+ }
+ printk("\n %s timing: (0x%04x) sample_CLKs=%d, recovery_CLKs=%d\n",
+ hwif->name, time, ((~time>>12)&3)+2, ((~time>>8)&3)+1);
+ print_triton_drive_flags (0, time & 0xf);
+ print_triton_drive_flags (1, (time >> 4) & 0xf);
+ }
+
+quit: if (rc) printk("ide: pcibios access failed - %s\n", pcibios_strerror(rc));
+}
+
FUNET's LINUX-ADM group, [email protected]
TCL-scripts by Sam Shen, [email protected]
with Sam's (original) version of this