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path: root/drivers/scsi/aic7xxx/aic7xxx_proc.c
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Diffstat (limited to 'drivers/scsi/aic7xxx/aic7xxx_proc.c')
-rw-r--r--drivers/scsi/aic7xxx/aic7xxx_proc.c45
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);
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