1 files changed, 44 insertions, 1 deletions

diff --git a/drivers/scsi/aic7xxx/aic7xxx_proc.c b/drivers/scsi/aic7xxx/aic7xxx_proc.c
index 3802c91f0b07..04a3506cf340 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_proc.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_proc.c
@@ -54,6 +54,49 @@ static void	ahc_dump_device_state(struct info_str *info,
 static int      ahc_proc_write_seeprom(struct ahc_softc *ahc,
                                        char *buffer, int length);
 
+/*
+ * Table of syncrates that don't follow the "divisible by 4"
+ * rule. This table will be expanded in future SCSI specs.
+ */
+static struct {
+        u_int period_factor;
+        u_int period;   /* in 100ths of ns */
+} scsi_syncrates[] = {
+        { 0x08, 625 },  /* FAST-160 */
+        { 0x09, 1250 }, /* FAST-80 */
+        { 0x0a, 2500 }, /* FAST-40 40MHz */
+        { 0x0b, 3030 }, /* FAST-40 33MHz */
+        { 0x0c, 5000 }  /* FAST-20 */
+};
+
+/*
+ * Return the frequency in kHz corresponding to the given
+ * sync period factor.
+ */
+static u_int
+ahc_calc_syncsrate(u_int period_factor)
+{
+        int i;
+        int num_syncrates;
+
+        num_syncrates = sizeof(scsi_syncrates) / sizeof(scsi_syncrates[0]);
+        /* See if the period is in the "exception" table */
+        for (i = 0; i < num_syncrates; i++) {
+
+                if (period_factor == scsi_syncrates[i].period_factor) {
+                        /* Period in kHz */
+                        return (100000000 / scsi_syncrates[i].period);
+                }
+        }
+
+        /*
+         * Wasn't in the table, so use the standard
+         * 4 times conversion.
+         */
+        return (10000000 / (period_factor * 4 * 10));
+}
+
+
 static void
 copy_mem_info(struct info_str *info, char *data, int len)
 {
@@ -106,7 +149,7 @@ ahc_format_transinfo(struct info_str *info, struct ahc_transinfo *tinfo)
         speed = 3300;
         freq = 0;
         if (tinfo->offset != 0) {
-                freq = aic_calc_syncsrate(tinfo->period);
+                freq = ahc_calc_syncsrate(tinfo->period);
                 speed = freq;
         }
         speed *= (0x01 << tinfo->width);