diff options
Diffstat (limited to 'drivers/scsi/aic7xxx/aic7xxx_proc.c')
| -rw-r--r-- | drivers/scsi/aic7xxx/aic7xxx_proc.c | 45 |
1 files changed, 44 insertions, 1 deletions
diff --git a/drivers/scsi/aic7xxx/aic7xxx_proc.c b/drivers/scsi/aic7xxx/aic7xxx_proc.c index 3802c91..04a3506 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); |
