[PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init()

From	Ondrej Zary <linux@rainbow-software.org>
Newsgroups	linux.kernel
Subject	[PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init()
Date	2016-10-30 23:50 +0100
Message-ID	<sy75o-2jv-9@gated-at.bofh.it> (permalink)
References	<sy75o-2jv-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Read back MODE_REG after writing it in NCR5380_init() to check if the
chip is really there.

This prevents hang when incorrect I/O address was specified by user.

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
---
 drivers/scsi/NCR5380.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index 01c0027..ce3156d 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -495,6 +495,11 @@ static int NCR5380_init(struct Scsi_Host *instance, int flags)
 
 	NCR5380_write(INITIATOR_COMMAND_REG, ICR_BASE);
 	NCR5380_write(MODE_REG, MR_BASE);
+	/* check if the chip is really there */
+	if (NCR5380_read(MODE_REG) != MR_BASE) {
+		NCR5380_exit(instance);
+		return -ENODEV;
+	}
 	NCR5380_write(TARGET_COMMAND_REG, 0);
 	NCR5380_write(SELECT_ENABLE_REG, 0);
 
-- 
Ondrej Zary

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[PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init() Ondrej Zary <linux@rainbow-software.org> - 2016-10-30 23:50 +0100
  Re: [PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init() Finn Thain <fthain@telegraphics.com.au> - 2016-10-31 04:20 +0100
    Re: [PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init() Ondrej Zary <linux@rainbow-software.org> - 2016-10-31 09:10 +0100
      Re: [PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init() Finn Thain <fthain@telegraphics.com.au> - 2016-10-31 10:40 +0100
  Re: [PATCH 3/3] NCR5380: Check for chip presence in NCR5380_init() Finn Thain <fthain@telegraphics.com.au> - 2016-10-31 04:40 +0100

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