[PATCH 3/6] g_NCR5380: Check for chip presence before calling NCR5380_init()

[Ondrej Zary]

Write and read back MODE_REG to check if the chip is really there
before doing more initialization.

This prevents hang when incorrect I/O address was specified by user (in
the most common case where no device is present there so all reads
result in 0xff).

Signed-off-by: Ondrej Zary <li...@rainbow-software.org>
---
 drivers/scsi/g_NCR5380.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 0d1f6ad..e713dba 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -322,6 +322,13 @@ static int generic_NCR5380_init_one(struct 
scsi_host_template *tpnt,
                }
        }
 
+       /* check if the chip is really there */
+       NCR5380_write(MODE_REG, 0);
+       if (NCR5380_read(MODE_REG) != 0) {
+               ret = -ENODEV;
+               goto out_unregister;
+       }
+
        ret = NCR5380_init(instance, flags | FLAG_LATE_DMA_SETUP);
        if (ret)
                goto out_unregister;
-- 
Ondrej Zary