[SCSI] wd33c93: Fast SCSI with WD33C93B

Attached are patches, which help to utilize more of the WD33C93B SCSI
controller's capabilities.

1) Added/changed all the necessary code to enable Burst Mode DMA. Only
   Single Byte DMA was used before.

2) Added/changed all the necessary code to enable Fast-10 SCSI transfers.

3) The original driver inadvertently used a transfer period of 1000-800ns
   (the lowest possible transfer rate) for asynchronous data transfers,
   instead of the (configurable) default period intended for this purpose,
   if the target responded to a SDTR not with a Reject-message, but with
   a zero-SDTR. This issue was fixed.
   Moreover, in case of a Reject the driver used the default-period's
   initialization-value instead of its (maybe smaller) current value. The
   missing assignment was added.

4) The driver's commandline- and proc-file-interface was augmented to
   handle the new options properly.

The WD33C93 manual, found at
http://www.datasheet.in/datasheet-html/W/D/3/WD33C93B_WesternDigital.pdf.html,
was very helpful.

Signed-off-by: peter fuerst <post@pfrst.de>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 248 insertions, 79 deletions

diff --git a/drivers/scsi/wd33c93.c b/drivers/scsi/wd33c93.c
index 835751600e93..fa4e08e508ad 100644
--- a/drivers/scsi/wd33c93.c
+++ b/drivers/scsi/wd33c93.c
@@ -69,6 +69,11 @@
  * Added support for pre -A chips, which don't have advanced features
  * and will generate CSR_RESEL rather than CSR_RESEL_AM.
  *      Richard Hirst <richard@sleepie.demon.co.uk>  August 2000
+ *
+ * Added support for Burst Mode DMA and Fast SCSI. Enabled the use of
+ * default_sx_per for asynchronous data transfers. Added adjustment
+ * of transfer periods in sx_table to the actual input-clock.
+ *  peter fuerst <post@pfrst.de>  February 2007
  */
 
 #include <linux/module.h>
@@ -86,9 +91,11 @@
 
 #include "wd33c93.h"
 
+#define optimum_sx_per(hostdata) (hostdata)->sx_table[1].period_ns
+
 
-#define WD33C93_VERSION    "1.26"
-#define WD33C93_DATE       "22/Feb/2003"
+#define WD33C93_VERSION    "1.26++"
+#define WD33C93_DATE       "10/Feb/2007"
 
 MODULE_AUTHOR("John Shifflett");
 MODULE_DESCRIPTION("Generic WD33C93 SCSI driver");
@@ -122,6 +129,13 @@ MODULE_LICENSE("GPL");
  *                    defines in wd33c93.h
  * -  clock:x        -x = clock input in MHz for WD33c93 chip. Normal values
  *                    would be from 8 through 20. Default is 8.
+ * -  burst:x        -x = 1 to use Burst Mode (or Demand-Mode) DMA, x = 0 to use
+ *                    Single Byte DMA, which is the default. Argument is
+ *                    optional - if not present, same as "burst:1".
+ * -  fast:x         -x = 1 to enable Fast SCSI, which is only effective with
+ *                    input-clock divisor 4 (WD33C93_FS_16_20), x = 0 to disable
+ *                    it, which is the default.  Argument is optional - if not
+ *                    present, same as "fast:1".
  * -  next           -No argument. Used to separate blocks of keywords when
  *                    there's more than one host adapter in the system.
  *
@@ -148,7 +162,7 @@ MODULE_LICENSE("GPL");
  */
 
 /* Normally, no defaults are specified */
-static char *setup_args[] = { "", "", "", "", "", "", "", "", "" };
+static char *setup_args[] = { "", "", "", "", "", "", "", "", "", "" };
 
 static char *setup_strings;
 module_param(setup_strings, charp, 0);
@@ -298,20 +312,8 @@ read_1_byte(const wd33c93_regs regs)
         return x;
 }
 
-static struct sx_period sx_table[] = {
-        {1, 0x20},
-        {252, 0x20},
-        {376, 0x30},
-        {500, 0x40},
-        {624, 0x50},
-        {752, 0x60},
-        {876, 0x70},
-        {1000, 0x00},
-        {0, 0}
-};
-
 static int
-round_period(unsigned int period)
+round_period(unsigned int period, const struct sx_period *sx_table)
 {
         int x;
 
@@ -324,17 +326,49 @@ round_period(unsigned int period)
         return 7;
 }
 
+/*
+ * Calculate Synchronous Transfer Register value from SDTR code.
+ */
 static uchar
-calc_sync_xfer(unsigned int period, unsigned int offset)
+calc_sync_xfer(unsigned int period, unsigned int offset, unsigned int fast,
+               const struct sx_period *sx_table)
 {
+        /* When doing Fast SCSI synchronous data transfers, the corresponding
+         * value in 'sx_table' is two times the actually used transfer period.
+         */
         uchar result;
 
+        if (offset && fast) {
+                fast = STR_FSS;
+                period *= 2;
+        } else {
+                fast = 0;
+        }
         period *= 4;            /* convert SDTR code to ns */
-        result = sx_table[round_period(period)].reg_value;
+        result = sx_table[round_period(period,sx_table)].reg_value;
         result |= (offset < OPTIMUM_SX_OFF) ? offset : OPTIMUM_SX_OFF;
+        result |= fast;
         return result;
 }
 
+/*
+ * Calculate SDTR code bytes [3],[4] from period and offset.
+ */
+static inline void
+calc_sync_msg(unsigned int period, unsigned int offset, unsigned int fast,
+                uchar  msg[2])
+{
+        /* 'period' is a "normal"-mode value, like the ones in 'sx_table'. The
+         * actually used transfer period for Fast SCSI synchronous data
+         * transfers is half that value.
+         */
+        period /= 4;
+        if (offset && fast)
+                period /= 2;
+        msg[0] = period;
+        msg[1] = offset;
+}
+
 int
 wd33c93_queuecommand(struct scsi_cmnd *cmd,
                 void (*done)(struct scsi_cmnd *))
@@ -632,7 +666,7 @@ wd33c93_execute(struct Scsi_Host *instance)
                                 write_wd33c93_count(regs,
                                                     cmd->SCp.this_residual);
                                 write_wd33c93(regs, WD_CONTROL,
-                                              CTRL_IDI | CTRL_EDI | CTRL_DMA);
+                                              CTRL_IDI | CTRL_EDI | hostdata->dma_mode);
                                 hostdata->dma = D_DMA_RUNNING;
                         }
                 } else
@@ -712,6 +746,8 @@ transfer_bytes(const wd33c93_regs regs, struct scsi_cmnd *cmd,
                 cmd->SCp.ptr = page_address(cmd->SCp.buffer->page) +
                     cmd->SCp.buffer->offset;
         }
+        if (!cmd->SCp.this_residual) /* avoid bogus setups */
+                return;
 
         write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,
                       hostdata->sync_xfer[cmd->device->id]);
@@ -744,7 +780,7 @@ transfer_bytes(const wd33c93_regs regs, struct scsi_cmnd *cmd,
 #ifdef PROC_STATISTICS
                 hostdata->dma_cnt++;
 #endif
-                write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_DMA);
+                write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | hostdata->dma_mode);
                 write_wd33c93_count(regs, cmd->SCp.this_residual);
 
                 if ((hostdata->level2 >= L2_DATA) ||
@@ -862,9 +898,6 @@ wd33c93_intr(struct Scsi_Host *instance)
                         hostdata->outgoing_msg[0] |= 0x40;
 
                 if (hostdata->sync_stat[cmd->device->id] == SS_FIRST) {
-#ifdef SYNC_DEBUG
-                        printk(" sending SDTR ");
-#endif
 
                         hostdata->sync_stat[cmd->device->id] = SS_WAITING;
 
@@ -878,14 +911,20 @@ wd33c93_intr(struct Scsi_Host *instance)
                         hostdata->outgoing_msg[2] = 3;
                         hostdata->outgoing_msg[3] = EXTENDED_SDTR;
                         if (hostdata->no_sync & (1 << cmd->device->id)) {
-                                hostdata->outgoing_msg[4] =
-                                    hostdata->default_sx_per / 4;
-                                hostdata->outgoing_msg[5] = 0;
+                                calc_sync_msg(hostdata->default_sx_per, 0,
+                                                0, hostdata->outgoing_msg + 4);
                         } else {
-                                hostdata->outgoing_msg[4] = OPTIMUM_SX_PER / 4;
-                                hostdata->outgoing_msg[5] = OPTIMUM_SX_OFF;
+                                calc_sync_msg(optimum_sx_per(hostdata),
+                                                OPTIMUM_SX_OFF,
+                                                hostdata->fast,
+                                                hostdata->outgoing_msg + 4);
                         }
                         hostdata->outgoing_len = 6;
+#ifdef SYNC_DEBUG
+                        ucp = hostdata->outgoing_msg + 1;
+                        printk(" sending SDTR %02x03%02x%02x%02x ",
+                                ucp[0], ucp[2], ucp[3], ucp[4]);
+#endif
                 } else
                         hostdata->outgoing_len = 1;
 
@@ -1001,8 +1040,13 @@ wd33c93_intr(struct Scsi_Host *instance)
 #ifdef SYNC_DEBUG
                             printk("-REJ-");
 #endif
-                        if (hostdata->sync_stat[cmd->device->id] == SS_WAITING)
+                        if (hostdata->sync_stat[cmd->device->id] == SS_WAITING) {
                                 hostdata->sync_stat[cmd->device->id] = SS_SET;
+                                /* we want default_sx_per, not DEFAULT_SX_PER */
+                                hostdata->sync_xfer[cmd->device->id] =
+                                        calc_sync_xfer(hostdata->default_sx_per
+                                                / 4, 0, 0, hostdata->sx_table);
+                        }
                         write_wd33c93_cmd(regs, WD_CMD_NEGATE_ACK);
                         hostdata->state = S_CONNECTED;
                         break;
@@ -1022,7 +1066,10 @@ wd33c93_intr(struct Scsi_Host *instance)
 
                                 switch (ucp[2]) {       /* what's the EXTENDED code? */
                                 case EXTENDED_SDTR:
-                                        id = calc_sync_xfer(ucp[3], ucp[4]);
+                                        /* default to default async period */
+                                        id = calc_sync_xfer(hostdata->
+                                                        default_sx_per / 4, 0,
+                                                        0, hostdata->sx_table);
                                         if (hostdata->sync_stat[cmd->device->id] !=
                                             SS_WAITING) {
 
@@ -1041,20 +1088,22 @@ wd33c93_intr(struct Scsi_Host *instance)
                                                 hostdata->outgoing_msg[1] = 3;
                                                 hostdata->outgoing_msg[2] =
                                                     EXTENDED_SDTR;
-                                                hostdata->outgoing_msg[3] =
-                                                    hostdata->default_sx_per /
-                                                    4;
-                                                hostdata->outgoing_msg[4] = 0;
+                                                calc_sync_msg(hostdata->
+                                                        default_sx_per, 0,
+                                                        0, hostdata->outgoing_msg + 3);
                                                 hostdata->outgoing_len = 5;
-                                                hostdata->sync_xfer[cmd->device->id] =
-                                                    calc_sync_xfer(hostdata->
-                                                                   default_sx_per
-                                                                   / 4, 0);
                                         } else {
-                                                hostdata->sync_xfer[cmd->device->id] = id;
+                                                if (ucp[4]) /* well, sync transfer */
+                                                        id = calc_sync_xfer(ucp[3], ucp[4],
+                                                                        hostdata->fast,
+                                                                        hostdata->sx_table);
+                                                else if (ucp[3]) /* very unlikely... */
+                                                        id = calc_sync_xfer(ucp[3], ucp[4],
+                                                                        0, hostdata->sx_table);
                                         }
+                                        hostdata->sync_xfer[cmd->device->id] = id;
 #ifdef SYNC_DEBUG
-                                        printk("sync_xfer=%02x",
+                                        printk(" sync_xfer=%02x\n",
                                                hostdata->sync_xfer[cmd->device->id]);
 #endif
                                         hostdata->sync_stat[cmd->device->id] =
@@ -1486,7 +1535,7 @@ reset_wd33c93(struct Scsi_Host *instance)
         write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
         write_wd33c93(regs, WD_SYNCHRONOUS_TRANSFER,
                       calc_sync_xfer(hostdata->default_sx_per / 4,
-                                     DEFAULT_SX_OFF));
+                                     DEFAULT_SX_OFF, 0, hostdata->sx_table));
         write_wd33c93(regs, WD_COMMAND, WD_CMD_RESET);
 
 
@@ -1512,6 +1561,9 @@ reset_wd33c93(struct Scsi_Host *instance)
         } else
                 hostdata->chip = C_UNKNOWN_CHIP;
 
+        if (hostdata->chip != C_WD33C93B)       /* Fast SCSI unavailable */
+                hostdata->fast = 0;
+
         write_wd33c93(regs, WD_TIMEOUT_PERIOD, TIMEOUT_PERIOD_VALUE);
         write_wd33c93(regs, WD_CONTROL, CTRL_IDI | CTRL_EDI | CTRL_POLLED);
 }
@@ -1533,7 +1585,8 @@ wd33c93_host_reset(struct scsi_cmnd * SCpnt)
         for (i = 0; i < 8; i++) {
                 hostdata->busy[i] = 0;
                 hostdata->sync_xfer[i] =
-                    calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF);
+                        calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF,
+                                        0, hostdata->sx_table);
                 hostdata->sync_stat[i] = SS_UNSET;      /* using default sync values */
         }
         hostdata->input_Q = NULL;
@@ -1782,6 +1835,98 @@ check_setup_args(char *key, int *flags, int *val, char *buf)
         return ++x;
 }
 
+/*
+ * Calculate internal data-transfer-clock cycle from input-clock
+ * frequency (/MHz) and fill 'sx_table'.
+ *
+ * The original driver used to rely on a fixed sx_table, containing periods
+ * for (only) the lower limits of the respective input-clock-frequency ranges
+ * (8-10/12-15/16-20 MHz). Although it seems, that no problems ocurred with
+ * this setting so far, it might be desirable to adjust the transfer periods
+ * closer to the really attached, possibly 25% higher, input-clock, since
+ * - the wd33c93 may really use a significant shorter period, than it has
+ *   negotiated (eg. thrashing the target, which expects 4/8MHz, with 5/10MHz
+ *   instead).
+ * - the wd33c93 may ask the target for a lower transfer rate, than the target
+ *   is capable of (eg. negotiating for an assumed minimum of 252ns instead of
+ *   possible 200ns, which indeed shows up in tests as an approx. 10% lower
+ *   transfer rate).
+ */
+static inline unsigned int
+round_4(unsigned int x)
+{
+        switch (x & 3) {
+                case 1: --x;
+                        break;
+                case 2: ++x;
+                case 3: ++x;
+        }
+        return x;
+}
+
+static void
+calc_sx_table(unsigned int mhz, struct sx_period sx_table[9])
+{
+        unsigned int d, i;
+        if (mhz < 11)
+                d = 2;  /* divisor for  8-10 MHz input-clock */
+        else if (mhz < 16)
+                d = 3;  /* divisor for 12-15 MHz input-clock */
+        else
+                d = 4;  /* divisor for 16-20 MHz input-clock */
+
+        d = (100000 * d) / 2 / mhz; /* 100 x DTCC / nanosec */
+
+        sx_table[0].period_ns = 1;
+        sx_table[0].reg_value = 0x20;
+        for (i = 1; i < 8; i++) {
+                sx_table[i].period_ns = round_4((i+1)*d / 100);
+                sx_table[i].reg_value = (i+1)*0x10;
+        }
+        sx_table[7].reg_value = 0;
+        sx_table[8].period_ns = 0;
+        sx_table[8].reg_value = 0;
+}
+
+/*
+ * check and, maybe, map an init- or "clock:"- argument.
+ */
+static uchar
+set_clk_freq(int freq, int *mhz)
+{
+        int x = freq;
+        if (WD33C93_FS_8_10 == freq)
+                freq = 8;
+        else if (WD33C93_FS_12_15 == freq)
+                freq = 12;
+        else if (WD33C93_FS_16_20 == freq)
+                freq = 16;
+        else if (freq > 7 && freq < 11)
+                x = WD33C93_FS_8_10;
+                else if (freq > 11 && freq < 16)
+                x = WD33C93_FS_12_15;
+                else if (freq > 15 && freq < 21)
+                x = WD33C93_FS_16_20;
+        else {
+                        /* Hmm, wouldn't it be safer to assume highest freq here? */
+                x = WD33C93_FS_8_10;
+                freq = 8;
+        }
+        *mhz = freq;
+        return x;
+}
+
+/*
+ * to be used with the resync: fast: ... options
+ */
+static inline void set_resync ( struct WD33C93_hostdata *hd, int mask )
+{
+        int i;
+        for (i = 0; i < 8; i++)
+                if (mask & (1 << i))
+                        hd->sync_stat[i] = SS_UNSET;
+}
+
 void
 wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
              dma_setup_t setup, dma_stop_t stop, int clock_freq)
@@ -1798,7 +1943,8 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
         hostdata = (struct WD33C93_hostdata *) instance->hostdata;
 
         hostdata->regs = regs;
-        hostdata->clock_freq = clock_freq;
+        hostdata->clock_freq = set_clk_freq(clock_freq, &i);
+        calc_sx_table(i, hostdata->sx_table);
         hostdata->dma_setup = setup;
         hostdata->dma_stop = stop;
         hostdata->dma_bounce_buffer = NULL;
@@ -1806,7 +1952,8 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
         for (i = 0; i < 8; i++) {
                 hostdata->busy[i] = 0;
                 hostdata->sync_xfer[i] =
-                    calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF);
+                        calc_sync_xfer(DEFAULT_SX_PER / 4, DEFAULT_SX_OFF,
+                                        0, hostdata->sx_table);
                 hostdata->sync_stat[i] = SS_UNSET;      /* using default sync values */
 #ifdef PROC_STATISTICS
                 hostdata->cmd_cnt[i] = 0;
@@ -1828,6 +1975,8 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
         hostdata->default_sx_per = DEFAULT_SX_PER;
         hostdata->no_sync = 0xff;       /* sync defaults to off */
         hostdata->no_dma = 0;   /* default is DMA enabled */
+        hostdata->fast = 0;     /* default is Fast SCSI transfers disabled */
+        hostdata->dma_mode = CTRL_DMA;  /* default is Single Byte DMA */
 
 #ifdef PROC_INTERFACE
         hostdata->proc = PR_VERSION | PR_INFO | PR_STATISTICS |
@@ -1839,6 +1988,11 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
 #endif
 #endif
 
+        if (check_setup_args("clock", &flags, &val, buf)) {
+                hostdata->clock_freq = set_clk_freq(val, &val);
+                calc_sx_table(val, hostdata->sx_table);
+        }
+
         if (check_setup_args("nosync", &flags, &val, buf))
                 hostdata->no_sync = val;
 
@@ -1847,7 +2001,8 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
 
         if (check_setup_args("period", &flags, &val, buf))
                 hostdata->default_sx_per =
-                    sx_table[round_period((unsigned int) val)].period_ns;
+                    hostdata->sx_table[round_period((unsigned int) val,
+                                                    hostdata->sx_table)].period_ns;
 
         if (check_setup_args("disconnect", &flags, &val, buf)) {
                 if ((val >= DIS_NEVER) && (val <= DIS_ALWAYS))
@@ -1862,17 +2017,12 @@ wd33c93_init(struct Scsi_Host *instance, const wd33c93_regs regs,
         if (check_setup_args("debug", &flags, &val, buf))
                 hostdata->args = val & DB_MASK;
 
-        if (check_setup_args("clock", &flags, &val, buf)) {
-                if (val > 7 && val < 11)
-                        val = WD33C93_FS_8_10;
-                else if (val > 11 && val < 16)
-                        val = WD33C93_FS_12_15;
-                else if (val > 15 && val < 21)
-                        val = WD33C93_FS_16_20;
-                else
-                        val = WD33C93_FS_8_10;
-                hostdata->clock_freq = val;
-        }
+        if (check_setup_args("burst", &flags, &val, buf))
+                hostdata->dma_mode = val ? CTRL_BURST:CTRL_DMA;
+
+        if (WD33C93_FS_16_20 == hostdata->clock_freq /* divisor 4 */
+                && check_setup_args("fast", &flags, &val, buf))
+                hostdata->fast = !!val;
 
         if ((i = check_setup_args("next", &flags, &val, buf))) {
                 while (i)
@@ -1917,53 +2067,65 @@ wd33c93_proc_info(struct Scsi_Host *instance, char *buf, char **start, off_t off
         char tbuf[128];
         struct WD33C93_hostdata *hd;
         struct scsi_cmnd *cmd;
-        int x, i;
+        int x;
         static int stop = 0;
 
         hd = (struct WD33C93_hostdata *) instance->hostdata;
 
 /* If 'in' is TRUE we need to _read_ the proc file. We accept the following
- * keywords (same format as command-line, but only ONE per read):
+ * keywords (same format as command-line, but arguments are not optional):
  *    debug
  *    disconnect
  *    period
  *    resync
  *    proc
  *    nodma
+ *    level2
+ *    burst
+ *    fast
+ *    nosync
  */
 
         if (in) {
                 buf[len] = '\0';
-                bp = buf;
+                for (bp = buf; *bp; ) {
+                        while (',' == *bp || ' ' == *bp)
+                                ++bp;
                 if (!strncmp(bp, "debug:", 6)) {
-                        bp += 6;
-                        hd->args = simple_strtoul(bp, NULL, 0) & DB_MASK;
+                                hd->args = simple_strtoul(bp+6, &bp, 0) & DB_MASK;
                 } else if (!strncmp(bp, "disconnect:", 11)) {
-                        bp += 11;
-                        x = simple_strtoul(bp, NULL, 0);
+                                x = simple_strtoul(bp+11, &bp, 0);
                         if (x < DIS_NEVER || x > DIS_ALWAYS)
                                 x = DIS_ADAPTIVE;
                         hd->disconnect = x;
                 } else if (!strncmp(bp, "period:", 7)) {
-                        bp += 7;
-                        x = simple_strtoul(bp, NULL, 0);
+                        x = simple_strtoul(bp+7, &bp, 0);
                         hd->default_sx_per =
-                            sx_table[round_period((unsigned int) x)].period_ns;
+                                hd->sx_table[round_period((unsigned int) x,
+                                                          hd->sx_table)].period_ns;
                 } else if (!strncmp(bp, "resync:", 7)) {
-                        bp += 7;
-                        x = simple_strtoul(bp, NULL, 0);
-                        for (i = 0; i < 7; i++)
-                                if (x & (1 << i))
-                                        hd->sync_stat[i] = SS_UNSET;
+                                set_resync(hd, (int)simple_strtoul(bp+7, &bp, 0));
                 } else if (!strncmp(bp, "proc:", 5)) {
-                        bp += 5;
-                        hd->proc = simple_strtoul(bp, NULL, 0);
+                                hd->proc = simple_strtoul(bp+5, &bp, 0);
                 } else if (!strncmp(bp, "nodma:", 6)) {
-                        bp += 6;
-                        hd->no_dma = simple_strtoul(bp, NULL, 0);
+                                hd->no_dma = simple_strtoul(bp+6, &bp, 0);
                 } else if (!strncmp(bp, "level2:", 7)) {
-                        bp += 7;
-                        hd->level2 = simple_strtoul(bp, NULL, 0);
+                                hd->level2 = simple_strtoul(bp+7, &bp, 0);
+                        } else if (!strncmp(bp, "burst:", 6)) {
+                                hd->dma_mode =
+                                        simple_strtol(bp+6, &bp, 0) ? CTRL_BURST:CTRL_DMA;
+                        } else if (!strncmp(bp, "fast:", 5)) {
+                                x = !!simple_strtol(bp+5, &bp, 0);
+                                if (x != hd->fast)
+                                        set_resync(hd, 0xff);
+                                hd->fast = x;
+                        } else if (!strncmp(bp, "nosync:", 7)) {
+                                x = simple_strtoul(bp+7, &bp, 0);
+                                set_resync(hd, x ^ hd->no_sync);
+                                hd->no_sync = x;
+                        } else {
+                                break; /* unknown keyword,syntax-error,... */
+                        }
                 }
                 return len;
         }
@@ -1977,8 +2139,9 @@ wd33c93_proc_info(struct Scsi_Host *instance, char *buf, char **start, off_t off
                 strcat(bp, tbuf);
         }
         if (hd->proc & PR_INFO) {
-                sprintf(tbuf, "\nclock_freq=%02x no_sync=%02x no_dma=%d",
-                        hd->clock_freq, hd->no_sync, hd->no_dma);
+                sprintf(tbuf, "\nclock_freq=%02x no_sync=%02x no_dma=%d"
+                        " dma_mode=%02x fast=%d",
+                        hd->clock_freq, hd->no_sync, hd->no_dma, hd->dma_mode, hd->fast);
                 strcat(bp, tbuf);
                 strcat(bp, "\nsync_xfer[] =       ");
                 for (x = 0; x < 7; x++) {
diff --git a/drivers/scsi/wd33c93.h b/drivers/scsi/wd33c93.h
index edcb0365cf0c..61ffb860dacc 100644
--- a/drivers/scsi/wd33c93.h
+++ b/drivers/scsi/wd33c93.h
@@ -155,6 +155,9 @@
 #define WD33C93_FS_12_15 OWNID_FS_12
 #define WD33C93_FS_16_20 OWNID_FS_16
 
+   /* pass input-clock explicitely. accepted mhz values are 8-10,12-20 */
+#define WD33C93_FS_MHZ(mhz) (mhz)
+
    /* Control register */
 #define CTRL_HSP     0x01
 #define CTRL_HA      0x02
@@ -253,6 +256,9 @@ struct WD33C93_hostdata {
     uchar            sync_stat[8];     /* status of sync negotiation per target */
     uchar            no_sync;          /* bitmask: don't do sync on these targets */
     uchar            no_dma;           /* set this flag to disable DMA */
+    uchar            dma_mode;         /* DMA Burst Mode or Single Byte DMA */
+    uchar            fast;             /* set this flag to enable Fast SCSI */
+    struct sx_period sx_table[9];      /* transfer periods for actual DTC-setting */
 #ifdef PROC_INTERFACE
     uchar            proc;             /* bitmask: what's in proc output */
 #ifdef PROC_STATISTICS