Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 879 insertions, 0 deletions

diff --git a/drivers/ide/pci/cmd640.c b/drivers/ide/pci/cmd640.c
new file mode 100644
index 000000000000..92a2b7caed58
--- /dev/null
+++ b/drivers/ide/pci/cmd640.c
@@ -0,0 +1,879 @@
+/*
+ *  linux/drivers/ide/pci/cmd640.c              Version 1.02  Sep 01, 1996
+ *
+ *  Copyright (C) 1995-1996  Linus Torvalds & authors (see below)
+ */
+
+/*
+ *  Original authors:   abramov@cecmow.enet.dec.com (Igor Abramov)
+ *                      mlord@pobox.com (Mark Lord)
+ *
+ *  See linux/MAINTAINERS for address of current maintainer.
+ *
+ *  This file provides support for the advanced features and bugs
+ *  of IDE interfaces using the CMD Technologies 0640 IDE interface chip.
+ *
+ *  These chips are basically fucked by design, and getting this driver
+ *  to work on every motherboard design that uses this screwed chip seems
+ *  bloody well impossible.  However, we're still trying.
+ *
+ *  Version 0.97 worked for everybody.
+ *
+ *  User feedback is essential.  Many thanks to the beta test team:
+ *
+ *  A.Hartgers@stud.tue.nl, JZDQC@CUNYVM.CUNY.edu, abramov@cecmow.enet.dec.com,
+ *  bardj@utopia.ppp.sn.no, bart@gaga.tue.nl, bbol001@cs.auckland.ac.nz,
+ *  chrisc@dbass.demon.co.uk, dalecki@namu26.Num.Math.Uni-Goettingen.de,
+ *  derekn@vw.ece.cmu.edu, florian@btp2x3.phy.uni-bayreuth.de,
+ *  flynn@dei.unipd.it, gadio@netvision.net.il, godzilla@futuris.net,
+ *  j@pobox.com, jkemp1@mises.uni-paderborn.de, jtoppe@hiwaay.net,
+ *  kerouac@ssnet.com, meskes@informatik.rwth-aachen.de, hzoli@cs.elte.hu,
+ *  peter@udgaard.isgtec.com, phil@tazenda.demon.co.uk, roadcapw@cfw.com,
+ *  s0033las@sun10.vsz.bme.hu, schaffer@tam.cornell.edu, sjd@slip.net,
+ *  steve@ei.org, ulrpeg@bigcomm.gun.de, ism@tardis.ed.ac.uk, mack@cray.com
+ *  liug@mama.indstate.edu, and others.
+ *
+ *  Version 0.01        Initial version, hacked out of ide.c,
+ *                      and #include'd rather than compiled separately.
+ *                      This will get cleaned up in a subsequent release.
+ *
+ *  Version 0.02        Fixes for vlb initialization code, enable prefetch
+ *                      for versions 'B' and 'C' of chip by default,
+ *                      some code cleanup.
+ *
+ *  Version 0.03        Added reset of secondary interface,
+ *                      and black list for devices which are not compatible
+ *                      with prefetch mode. Separate function for setting
+ *                      prefetch is added, possibly it will be called some
+ *                      day from ioctl processing code.
+ *
+ *  Version 0.04        Now configs/compiles separate from ide.c
+ *
+ *  Version 0.05        Major rewrite of interface timing code.
+ *                      Added new function cmd640_set_mode to set PIO mode
+ *                      from ioctl call. New drives added to black list.
+ *
+ *  Version 0.06        More code cleanup. Prefetch is enabled only for
+ *                      detected hard drives, not included in prefetch
+ *                      black list.
+ *
+ *  Version 0.07        Changed to more conservative drive tuning policy.
+ *                      Unknown drives, which report PIO < 4 are set to
+ *                      (reported_PIO - 1) if it is supported, or to PIO0.
+ *                      List of known drives extended by info provided by
+ *                      CMD at their ftp site.
+ *
+ *  Version 0.08        Added autotune/noautotune support.
+ *
+ *  Version 0.09        Try to be smarter about 2nd port enabling.
+ *  Version 0.10        Be nice and don't reset 2nd port.
+ *  Version 0.11        Try to handle more weird situations.
+ *
+ *  Version 0.12        Lots of bug fixes from Laszlo Peter
+ *                      irq unmasking disabled for reliability.
+ *                      try to be even smarter about the second port.
+ *                      tidy up source code formatting.
+ *  Version 0.13        permit irq unmasking again.
+ *  Version 0.90        massive code cleanup, some bugs fixed.
+ *                      defaults all drives to PIO mode0, prefetch off.
+ *                      autotune is OFF by default, with compile time flag.
+ *                      prefetch can be turned OFF/ON using "hdparm -p8/-p9"
+ *                       (requires hdparm-3.1 or newer)
+ *  Version 0.91        first release to linux-kernel list.
+ *  Version 0.92        move initial reg dump to separate callable function
+ *                      change "readahead" to "prefetch" to avoid confusion
+ *  Version 0.95        respect original BIOS timings unless autotuning.
+ *                      tons of code cleanup and rearrangement.
+ *                      added CONFIG_BLK_DEV_CMD640_ENHANCED option
+ *                      prevent use of unmask when prefetch is on
+ *  Version 0.96        prevent use of io_32bit when prefetch is off
+ *  Version 0.97        fix VLB secondary interface for sjd@slip.net
+ *                      other minor tune-ups:  0.96 was very good.
+ *  Version 0.98        ignore PCI version when disabled by BIOS
+ *  Version 0.99        display setup/active/recovery clocks with PIO mode
+ *  Version 1.00        Mmm.. cannot depend on PCMD_ENA in all systems
+ *  Version 1.01        slow/fast devsel can be selected with "hdparm -p6/-p7"
+ *                       ("fast" is necessary for 32bit I/O in some systems)
+ *  Version 1.02        fix bug that resulted in slow "setup times"
+ *                       (patch courtesy of Zoltan Hidvegi)
+ */
+
+#undef REALLY_SLOW_IO           /* most systems can safely undef this */
+#define CMD640_PREFETCH_MASKS 1
+
+//#define CMD640_DUMP_REGS
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/ioport.h>
+#include <linux/blkdev.h>
+#include <linux/hdreg.h>
+#include <linux/ide.h>
+#include <linux/init.h>
+
+#include <asm/io.h>
+
+/*
+ * This flag is set in ide.c by the parameter:  ide0=cmd640_vlb
+ */
+int cmd640_vlb = 0;
+
+/*
+ * CMD640 specific registers definition.
+ */
+
+#define VID             0x00
+#define DID             0x02
+#define PCMD            0x04
+#define   PCMD_ENA      0x01
+#define PSTTS           0x06
+#define REVID           0x08
+#define PROGIF          0x09
+#define SUBCL           0x0a
+#define BASCL           0x0b
+#define BaseA0          0x10
+#define BaseA1          0x14
+#define BaseA2          0x18
+#define BaseA3          0x1c
+#define INTLINE         0x3c
+#define INPINE          0x3d
+
+#define CFR             0x50
+#define   CFR_DEVREV            0x03
+#define   CFR_IDE01INTR         0x04
+#define   CFR_DEVID             0x18
+#define   CFR_AT_VESA_078h      0x20
+#define   CFR_DSA1              0x40
+#define   CFR_DSA0              0x80
+
+#define CNTRL           0x51
+#define   CNTRL_DIS_RA0         0x40
+#define   CNTRL_DIS_RA1         0x80
+#define   CNTRL_ENA_2ND         0x08
+
+#define CMDTIM          0x52
+#define ARTTIM0         0x53
+#define DRWTIM0         0x54
+#define ARTTIM1         0x55
+#define DRWTIM1         0x56
+#define ARTTIM23        0x57
+#define   ARTTIM23_DIS_RA2      0x04
+#define   ARTTIM23_DIS_RA3      0x08
+#define DRWTIM23        0x58
+#define BRST            0x59
+
+/*
+ * Registers and masks for easy access by drive index:
+ */
+static u8 prefetch_regs[4]  = {CNTRL, CNTRL, ARTTIM23, ARTTIM23};
+static u8 prefetch_masks[4] = {CNTRL_DIS_RA0, CNTRL_DIS_RA1, ARTTIM23_DIS_RA2, ARTTIM23_DIS_RA3};
+
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+
+static u8 arttim_regs[4] = {ARTTIM0, ARTTIM1, ARTTIM23, ARTTIM23};
+static u8 drwtim_regs[4] = {DRWTIM0, DRWTIM1, DRWTIM23, DRWTIM23};
+
+/*
+ * Current cmd640 timing values for each drive.
+ * The defaults for each are the slowest possible timings.
+ */
+static u8 setup_counts[4]    = {4, 4, 4, 4};     /* Address setup count (in clocks) */
+static u8 active_counts[4]   = {16, 16, 16, 16}; /* Active count   (encoded) */
+static u8 recovery_counts[4] = {16, 16, 16, 16}; /* Recovery count (encoded) */
+
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+
+/*
+ * These are initialized to point at the devices we control
+ */
+static ide_hwif_t  *cmd_hwif0, *cmd_hwif1;
+static ide_drive_t *cmd_drives[4];
+
+/*
+ * Interface to access cmd640x registers
+ */
+static unsigned int cmd640_key;
+static void (*__put_cmd640_reg)(u16 reg, u8 val);
+static u8 (*__get_cmd640_reg)(u16 reg);
+
+/*
+ * This is read from the CFR reg, and is used in several places.
+ */
+static unsigned int cmd640_chip_version;
+
+/*
+ * The CMD640x chip does not support DWORD config write cycles, but some
+ * of the BIOSes use them to implement the config services.
+ * Therefore, we must use direct IO instead.
+ */
+
+/* PCI method 1 access */
+
+static void put_cmd640_reg_pci1 (u16 reg, u8 val)
+{
+        outl_p((reg & 0xfc) | cmd640_key, 0xcf8);
+        outb_p(val, (reg & 3) | 0xcfc);
+}
+
+static u8 get_cmd640_reg_pci1 (u16 reg)
+{
+        outl_p((reg & 0xfc) | cmd640_key, 0xcf8);
+        return inb_p((reg & 3) | 0xcfc);
+}
+
+/* PCI method 2 access (from CMD datasheet) */
+
+static void put_cmd640_reg_pci2 (u16 reg, u8 val)
+{
+        outb_p(0x10, 0xcf8);
+        outb_p(val, cmd640_key + reg);
+        outb_p(0, 0xcf8);
+}
+
+static u8 get_cmd640_reg_pci2 (u16 reg)
+{
+        u8 b;
+
+        outb_p(0x10, 0xcf8);
+        b = inb_p(cmd640_key + reg);
+        outb_p(0, 0xcf8);
+        return b;
+}
+
+/* VLB access */
+
+static void put_cmd640_reg_vlb (u16 reg, u8 val)
+{
+        outb_p(reg, cmd640_key);
+        outb_p(val, cmd640_key + 4);
+}
+
+static u8 get_cmd640_reg_vlb (u16 reg)
+{
+        outb_p(reg, cmd640_key);
+        return inb_p(cmd640_key + 4);
+}
+
+static u8 get_cmd640_reg(u16 reg)
+{
+        u8 b;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+        b = __get_cmd640_reg(reg);
+        spin_unlock_irqrestore(&ide_lock, flags);
+        return b;
+}
+
+static void put_cmd640_reg(u16 reg, u8 val)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+        __put_cmd640_reg(reg,val);
+        spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+static int __init match_pci_cmd640_device (void)
+{
+        const u8 ven_dev[4] = {0x95, 0x10, 0x40, 0x06};
+        unsigned int i;
+        for (i = 0; i < 4; i++) {
+                if (get_cmd640_reg(i) != ven_dev[i])
+                        return 0;
+        }
+#ifdef STUPIDLY_TRUST_BROKEN_PCMD_ENA_BIT
+        if ((get_cmd640_reg(PCMD) & PCMD_ENA) == 0) {
+                printk("ide: cmd640 on PCI disabled by BIOS\n");
+                return 0;
+        }
+#endif /* STUPIDLY_TRUST_BROKEN_PCMD_ENA_BIT */
+        return 1; /* success */
+}
+
+/*
+ * Probe for CMD640x -- pci method 1
+ */
+static int __init probe_for_cmd640_pci1 (void)
+{
+        __get_cmd640_reg = get_cmd640_reg_pci1;
+        __put_cmd640_reg = put_cmd640_reg_pci1;
+        for (cmd640_key = 0x80000000;
+             cmd640_key <= 0x8000f800;
+             cmd640_key += 0x800) {
+                if (match_pci_cmd640_device())
+                        return 1; /* success */
+        }
+        return 0;
+}
+
+/*
+ * Probe for CMD640x -- pci method 2
+ */
+static int __init probe_for_cmd640_pci2 (void)
+{
+        __get_cmd640_reg = get_cmd640_reg_pci2;
+        __put_cmd640_reg = put_cmd640_reg_pci2;
+        for (cmd640_key = 0xc000; cmd640_key <= 0xcf00; cmd640_key += 0x100) {
+                if (match_pci_cmd640_device())
+                        return 1; /* success */
+        }
+        return 0;
+}
+
+/*
+ * Probe for CMD640x -- vlb
+ */
+static int __init probe_for_cmd640_vlb (void)
+{
+        u8 b;
+
+        __get_cmd640_reg = get_cmd640_reg_vlb;
+        __put_cmd640_reg = put_cmd640_reg_vlb;
+        cmd640_key = 0x178;
+        b = get_cmd640_reg(CFR);
+        if (b == 0xff || b == 0x00 || (b & CFR_AT_VESA_078h)) {
+                cmd640_key = 0x78;
+                b = get_cmd640_reg(CFR);
+                if (b == 0xff || b == 0x00 || !(b & CFR_AT_VESA_078h))
+                        return 0;
+        }
+        return 1; /* success */
+}
+
+/*
+ *  Returns 1 if an IDE interface/drive exists at 0x170,
+ *  Returns 0 otherwise.
+ */
+static int __init secondary_port_responding (void)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+
+        outb_p(0x0a, 0x170 + IDE_SELECT_OFFSET);        /* select drive0 */
+        udelay(100);
+        if ((inb_p(0x170 + IDE_SELECT_OFFSET) & 0x1f) != 0x0a) {
+                outb_p(0x1a, 0x170 + IDE_SELECT_OFFSET); /* select drive1 */
+                udelay(100);
+                if ((inb_p(0x170 + IDE_SELECT_OFFSET) & 0x1f) != 0x1a) {
+                        spin_unlock_irqrestore(&ide_lock, flags);
+                        return 0; /* nothing responded */
+                }
+        }
+        spin_unlock_irqrestore(&ide_lock, flags);
+        return 1; /* success */
+}
+
+#ifdef CMD640_DUMP_REGS
+/*
+ * Dump out all cmd640 registers.  May be called from ide.c
+ */
+static void cmd640_dump_regs (void)
+{
+        unsigned int reg = cmd640_vlb ? 0x50 : 0x00;
+
+        /* Dump current state of chip registers */
+        printk("ide: cmd640 internal register dump:");
+        for (; reg <= 0x59; reg++) {
+                if (!(reg & 0x0f))
+                        printk("\n%04x:", reg);
+                printk(" %02x", get_cmd640_reg(reg));
+        }
+        printk("\n");
+}
+#endif
+
+/*
+ * Check whether prefetch is on for a drive,
+ * and initialize the unmask flags for safe operation.
+ */
+static void __init check_prefetch (unsigned int index)
+{
+        ide_drive_t *drive = cmd_drives[index];
+        u8 b = get_cmd640_reg(prefetch_regs[index]);
+
+        if (b & prefetch_masks[index]) {        /* is prefetch off? */
+                drive->no_unmask = 0;
+                drive->no_io_32bit = 1;
+                drive->io_32bit = 0;
+        } else {
+#if CMD640_PREFETCH_MASKS
+                drive->no_unmask = 1;
+                drive->unmask = 0;
+#endif
+                drive->no_io_32bit = 0;
+        }
+}
+
+/*
+ * Figure out which devices we control
+ */
+static void __init setup_device_ptrs (void)
+{
+        unsigned int i;
+
+        cmd_hwif0 = &ide_hwifs[0]; /* default, if not found below */
+        cmd_hwif1 = &ide_hwifs[1]; /* default, if not found below */
+        for (i = 0; i < MAX_HWIFS; i++) {
+                ide_hwif_t *hwif = &ide_hwifs[i];
+                if (hwif->chipset == ide_unknown || hwif->chipset == ide_forced) {
+                        if (hwif->io_ports[IDE_DATA_OFFSET] == 0x1f0)
+                                cmd_hwif0 = hwif;
+                        else if (hwif->io_ports[IDE_DATA_OFFSET] == 0x170)
+                                cmd_hwif1 = hwif;
+                }
+        }
+        cmd_drives[0] = &cmd_hwif0->drives[0];
+        cmd_drives[1] = &cmd_hwif0->drives[1];
+        cmd_drives[2] = &cmd_hwif1->drives[0];
+        cmd_drives[3] = &cmd_hwif1->drives[1];
+}
+
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+
+/*
+ * Sets prefetch mode for a drive.
+ */
+static void set_prefetch_mode (unsigned int index, int mode)
+{
+        ide_drive_t *drive = cmd_drives[index];
+        int reg = prefetch_regs[index];
+        u8 b;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+        b = __get_cmd640_reg(reg);
+        if (mode) {     /* want prefetch on? */
+#if CMD640_PREFETCH_MASKS
+                drive->no_unmask = 1;
+                drive->unmask = 0;
+#endif
+                drive->no_io_32bit = 0;
+                b &= ~prefetch_masks[index];    /* enable prefetch */
+        } else {
+                drive->no_unmask = 0;
+                drive->no_io_32bit = 1;
+                drive->io_32bit = 0;
+                b |= prefetch_masks[index];     /* disable prefetch */
+        }
+        __put_cmd640_reg(reg, b);
+        spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+/*
+ * Dump out current drive clocks settings
+ */
+static void display_clocks (unsigned int index)
+{
+        u8 active_count, recovery_count;
+
+        active_count = active_counts[index];
+        if (active_count == 1)
+                ++active_count;
+        recovery_count = recovery_counts[index];
+        if (active_count > 3 && recovery_count == 1)
+                ++recovery_count;
+        if (cmd640_chip_version > 1)
+                recovery_count += 1;  /* cmd640b uses (count + 1)*/
+        printk(", clocks=%d/%d/%d\n", setup_counts[index], active_count, recovery_count);
+}
+
+/*
+ * Pack active and recovery counts into single byte representation
+ * used by controller
+ */
+inline static u8 pack_nibbles (u8 upper, u8 lower)
+{
+        return ((upper & 0x0f) << 4) | (lower & 0x0f);
+}
+
+/*
+ * This routine retrieves the initial drive timings from the chipset.
+ */
+static void __init retrieve_drive_counts (unsigned int index)
+{
+        u8 b;
+
+        /*
+         * Get the internal setup timing, and convert to clock count
+         */
+        b = get_cmd640_reg(arttim_regs[index]) & ~0x3f;
+        switch (b) {
+                case 0x00: b = 4; break;
+                case 0x80: b = 3; break;
+                case 0x40: b = 2; break;
+                default:   b = 5; break;
+        }
+        setup_counts[index] = b;
+
+        /*
+         * Get the active/recovery counts
+         */
+        b = get_cmd640_reg(drwtim_regs[index]);
+        active_counts[index]   = (b >> 4)   ? (b >> 4)   : 0x10;
+        recovery_counts[index] = (b & 0x0f) ? (b & 0x0f) : 0x10;
+}
+
+
+/*
+ * This routine writes the prepared setup/active/recovery counts
+ * for a drive into the cmd640 chipset registers to active them.
+ */
+static void program_drive_counts (unsigned int index)
+{
+        unsigned long flags;
+        u8 setup_count    = setup_counts[index];
+        u8 active_count   = active_counts[index];
+        u8 recovery_count = recovery_counts[index];
+
+        /*
+         * Set up address setup count and drive read/write timing registers.
+         * Primary interface has individual count/timing registers for
+         * each drive.  Secondary interface has one common set of registers,
+         * so we merge the timings, using the slowest value for each timing.
+         */
+        if (index > 1) {
+                unsigned int mate;
+                if (cmd_drives[mate = index ^ 1]->present) {
+                        if (setup_count < setup_counts[mate])
+                                setup_count = setup_counts[mate];
+                        if (active_count < active_counts[mate])
+                                active_count = active_counts[mate];
+                        if (recovery_count < recovery_counts[mate])
+                                recovery_count = recovery_counts[mate];
+                }
+        }
+
+        /*
+         * Convert setup_count to internal chipset representation
+         */
+        switch (setup_count) {
+                case 4:  setup_count = 0x00; break;
+                case 3:  setup_count = 0x80; break;
+                case 1:
+                case 2:  setup_count = 0x40; break;
+                default: setup_count = 0xc0; /* case 5 */
+        }
+
+        /*
+         * Now that everything is ready, program the new timings
+         */
+        spin_lock_irqsave(&ide_lock, flags);
+        /*
+         * Program the address_setup clocks into ARTTIM reg,
+         * and then the active/recovery counts into the DRWTIM reg
+         * (this converts counts of 16 into counts of zero -- okay).
+         */
+        setup_count |= __get_cmd640_reg(arttim_regs[index]) & 0x3f;
+        __put_cmd640_reg(arttim_regs[index], setup_count);
+        __put_cmd640_reg(drwtim_regs[index], pack_nibbles(active_count, recovery_count));
+        spin_unlock_irqrestore(&ide_lock, flags);
+}
+
+/*
+ * Set a specific pio_mode for a drive
+ */
+static void cmd640_set_mode (unsigned int index, u8 pio_mode, unsigned int cycle_time)
+{
+        int setup_time, active_time, recovery_time, clock_time;
+        u8 setup_count, active_count, recovery_count, recovery_count2, cycle_count;
+        int bus_speed = system_bus_clock();
+
+        if (pio_mode > 5)
+                pio_mode = 5;
+        setup_time  = ide_pio_timings[pio_mode].setup_time;
+        active_time = ide_pio_timings[pio_mode].active_time;
+        recovery_time = cycle_time - (setup_time + active_time);
+        clock_time = 1000 / bus_speed;
+        cycle_count = (cycle_time + clock_time - 1) / clock_time;
+
+        setup_count = (setup_time + clock_time - 1) / clock_time;
+
+        active_count = (active_time + clock_time - 1) / clock_time;
+        if (active_count < 2)
+                active_count = 2; /* minimum allowed by cmd640 */
+
+        recovery_count = (recovery_time + clock_time - 1) / clock_time;
+        recovery_count2 = cycle_count - (setup_count + active_count);
+        if (recovery_count2 > recovery_count)
+                recovery_count = recovery_count2;
+        if (recovery_count < 2)
+                recovery_count = 2; /* minimum allowed by cmd640 */
+        if (recovery_count > 17) {
+                active_count += recovery_count - 17;
+                recovery_count = 17;
+        }
+        if (active_count > 16)
+                active_count = 16; /* maximum allowed by cmd640 */
+        if (cmd640_chip_version > 1)
+                recovery_count -= 1;  /* cmd640b uses (count + 1)*/
+        if (recovery_count > 16)
+                recovery_count = 16; /* maximum allowed by cmd640 */
+
+        setup_counts[index]    = setup_count;
+        active_counts[index]   = active_count;
+        recovery_counts[index] = recovery_count;
+
+        /*
+         * In a perfect world, we might set the drive pio mode here
+         * (using WIN_SETFEATURE) before continuing.
+         *
+         * But we do not, because:
+         *      1) this is the wrong place to do it (proper is do_special() in ide.c)
+         *      2) in practice this is rarely, if ever, necessary
+         */
+        program_drive_counts (index);
+}
+
+/*
+ * Drive PIO mode selection:
+ */
+static void cmd640_tune_drive (ide_drive_t *drive, u8 mode_wanted)
+{
+        u8 b;
+        ide_pio_data_t  d;
+        unsigned int index = 0;
+
+        while (drive != cmd_drives[index]) {
+                if (++index > 3) {
+                        printk("%s: bad news in cmd640_tune_drive\n", drive->name);
+                        return;
+                }
+        }
+        switch (mode_wanted) {
+                case 6: /* set fast-devsel off */
+                case 7: /* set fast-devsel on */
+                        mode_wanted &= 1;
+                        b = get_cmd640_reg(CNTRL) & ~0x27;
+                        if (mode_wanted)
+                                b |= 0x27;
+                        put_cmd640_reg(CNTRL, b);
+                        printk("%s: %sabled cmd640 fast host timing (devsel)\n", drive->name, mode_wanted ? "en" : "dis");
+                        return;
+
+                case 8: /* set prefetch off */
+                case 9: /* set prefetch on */
+                        mode_wanted &= 1;
+                        set_prefetch_mode(index, mode_wanted);
+                        printk("%s: %sabled cmd640 prefetch\n", drive->name, mode_wanted ? "en" : "dis");
+                        return;
+        }
+
+        (void) ide_get_best_pio_mode (drive, mode_wanted, 5, &d);
+        cmd640_set_mode (index, d.pio_mode, d.cycle_time);
+
+        printk ("%s: selected cmd640 PIO mode%d (%dns)%s",
+                drive->name,
+                d.pio_mode,
+                d.cycle_time,
+                d.overridden ? " (overriding vendor mode)" : "");
+        display_clocks(index);
+        return;
+}
+
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+
+static int pci_conf1(void)
+{
+        u32 tmp;
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+        outb(0x01, 0xCFB);
+        tmp = inl(0xCF8);
+        outl(0x80000000, 0xCF8);
+        if (inl(0xCF8) == 0x80000000) {
+                outl(tmp, 0xCF8);
+                spin_unlock_irqrestore(&ide_lock, flags);
+                return 1;
+        }
+        outl(tmp, 0xCF8);
+        spin_unlock_irqrestore(&ide_lock, flags);
+        return 0;
+}
+
+static int pci_conf2(void)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&ide_lock, flags);
+        outb(0x00, 0xCFB);
+        outb(0x00, 0xCF8);
+        outb(0x00, 0xCFA);
+        if (inb(0xCF8) == 0x00 && inb(0xCF8) == 0x00) {
+                spin_unlock_irqrestore(&ide_lock, flags);
+                return 1;
+        }
+        spin_unlock_irqrestore(&ide_lock, flags);
+        return 0;
+}
+
+/*
+ * Probe for a cmd640 chipset, and initialize it if found.  Called from ide.c
+ */
+int __init ide_probe_for_cmd640x (void)
+{
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+        int second_port_toggled = 0;
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+        int second_port_cmd640 = 0;
+        const char *bus_type, *port2;
+        unsigned int index;
+        u8 b, cfr;
+
+        if (cmd640_vlb && probe_for_cmd640_vlb()) {
+                bus_type = "VLB";
+        } else {
+                cmd640_vlb = 0;
+                /* Find out what kind of PCI probing is supported otherwise
+                   Justin Gibbs will sulk.. */
+                if (pci_conf1() && probe_for_cmd640_pci1())
+                        bus_type = "PCI (type1)";
+                else if (pci_conf2() && probe_for_cmd640_pci2())
+                        bus_type = "PCI (type2)";
+                else
+                        return 0;
+        }
+        /*
+         * Undocumented magic (there is no 0x5b reg in specs)
+         */
+        put_cmd640_reg(0x5b, 0xbd);
+        if (get_cmd640_reg(0x5b) != 0xbd) {
+                printk(KERN_ERR "ide: cmd640 init failed: wrong value in reg 0x5b\n");
+                return 0;
+        }
+        put_cmd640_reg(0x5b, 0);
+
+#ifdef CMD640_DUMP_REGS
+        cmd640_dump_regs();
+#endif
+
+        /*
+         * Documented magic begins here
+         */
+        cfr = get_cmd640_reg(CFR);
+        cmd640_chip_version = cfr & CFR_DEVREV;
+        if (cmd640_chip_version == 0) {
+                printk ("ide: bad cmd640 revision: %d\n", cmd640_chip_version);
+                return 0;
+        }
+
+        /*
+         * Initialize data for primary port
+         */
+        setup_device_ptrs ();
+        printk("%s: buggy cmd640%c interface on %s, config=0x%02x\n",
+               cmd_hwif0->name, 'a' + cmd640_chip_version - 1, bus_type, cfr);
+        cmd_hwif0->chipset = ide_cmd640;
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+        cmd_hwif0->tuneproc = &cmd640_tune_drive;
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+
+        /*
+         * Ensure compatibility by always using the slowest timings
+         * for access to the drive's command register block,
+         * and reset the prefetch burstsize to default (512 bytes).
+         *
+         * Maybe we need a way to NOT do these on *some* systems?
+         */
+        put_cmd640_reg(CMDTIM, 0);
+        put_cmd640_reg(BRST, 0x40);
+
+        /*
+         * Try to enable the secondary interface, if not already enabled
+         */
+        if (cmd_hwif1->noprobe) {
+                port2 = "not probed";
+        } else {
+                b = get_cmd640_reg(CNTRL);
+                if (secondary_port_responding()) {
+                        if ((b & CNTRL_ENA_2ND)) {
+                                second_port_cmd640 = 1;
+                                port2 = "okay";
+                        } else if (cmd640_vlb) {
+                                second_port_cmd640 = 1;
+                                port2 = "alive";
+                        } else
+                                port2 = "not cmd640";
+                } else {
+                        put_cmd640_reg(CNTRL, b ^ CNTRL_ENA_2ND); /* toggle the bit */
+                        if (secondary_port_responding()) {
+                                second_port_cmd640 = 1;
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+                                second_port_toggled = 1;
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+                                port2 = "enabled";
+                        } else {
+                                put_cmd640_reg(CNTRL, b); /* restore original setting */
+                                port2 = "not responding";
+                        }
+                }
+        }
+
+        /*
+         * Initialize data for secondary cmd640 port, if enabled
+         */
+        if (second_port_cmd640) {
+                cmd_hwif0->serialized = 1;
+                cmd_hwif1->serialized = 1;
+                cmd_hwif1->chipset = ide_cmd640;
+                cmd_hwif0->mate = cmd_hwif1;
+                cmd_hwif1->mate = cmd_hwif0;
+                cmd_hwif1->channel = 1;
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+                cmd_hwif1->tuneproc = &cmd640_tune_drive;
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+        }
+        printk(KERN_INFO "%s: %sserialized, secondary interface %s\n", cmd_hwif1->name,
+                cmd_hwif0->serialized ? "" : "not ", port2);
+
+        /*
+         * Establish initial timings/prefetch for all drives.
+         * Do not unnecessarily disturb any prior BIOS setup of these.
+         */
+        for (index = 0; index < (2 + (second_port_cmd640 << 1)); index++) {
+                ide_drive_t *drive = cmd_drives[index];
+#ifdef CONFIG_BLK_DEV_CMD640_ENHANCED
+                if (drive->autotune || ((index > 1) && second_port_toggled)) {
+                        /*
+                         * Reset timing to the slowest speed and turn off prefetch.
+                         * This way, the drive identify code has a better chance.
+                         */
+                        setup_counts    [index] = 4;    /* max possible */
+                        active_counts   [index] = 16;   /* max possible */
+                        recovery_counts [index] = 16;   /* max possible */
+                        program_drive_counts (index);
+                        set_prefetch_mode (index, 0);
+                        printk("cmd640: drive%d timings/prefetch cleared\n", index);
+                } else {
+                        /*
+                         * Record timings/prefetch without changing them.
+                         * This preserves any prior BIOS setup.
+                         */
+                        retrieve_drive_counts (index);
+                        check_prefetch (index);
+                        printk("cmd640: drive%d timings/prefetch(%s) preserved",
+                                index, drive->no_io_32bit ? "off" : "on");
+                        display_clocks(index);
+                }
+#else
+                /*
+                 * Set the drive unmask flags to match the prefetch setting
+                 */
+                check_prefetch (index);
+                printk("cmd640: drive%d timings/prefetch(%s) preserved\n",
+                        index, drive->no_io_32bit ? "off" : "on");
+#endif /* CONFIG_BLK_DEV_CMD640_ENHANCED */
+        }
+
+#ifdef CMD640_DUMP_REGS
+        cmd640_dump_regs();
+#endif
+        return 1;
+}
+