| Message ID | 1477867203-7480-3-git-send-email-linux@rainbow-software.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
On Sun, 30 Oct 2016, Ondrej Zary wrote: > 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; > + } This doesn't belong in the core driver. Only the 5380 ISA drivers have configurable base addresses. Also, MR_BASE == 0, so that test is likely to be ineffectual anyway. This patch doesn't really add any value AFAICT.
On Sun, 30 Oct 2016, Ondrej Zary wrote: > 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. Do you know whereabouts in the driver the hang happens? Maybe there is a robustness issue there. Card type detection (and vacant slot detection) is a good idea but I'm not sure how we can detect this chip reliably.
On Monday 31 October 2016, Finn Thain wrote: > On Sun, 30 Oct 2016, Ondrej Zary wrote: > > 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; > > + } > > This doesn't belong in the core driver. Only the 5380 ISA drivers have > configurable base addresses. > > Also, MR_BASE == 0, so that test is likely to be ineffectual anyway. This > patch doesn't really add any value AFAICT. This fixes the most common problem: no device present at the specified I/O address, all reads result in 0xff.
On Mon, 31 Oct 2016, Ondrej Zary wrote: > On Monday 31 October 2016, Finn Thain wrote: > > On Sun, 30 Oct 2016, Ondrej Zary wrote: > > > 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; > > > + } > > > > This doesn't belong in the core driver. Only the 5380 ISA drivers have > > configurable base addresses. > > > > Also, MR_BASE == 0, so that test is likely to be ineffectual anyway. > > This patch doesn't really add any value AFAICT. > > This fixes the most common problem: no device present at the specified > I/O address, all reads result in 0xff. > ISTR that's true for ISA in general, so I guess it would be okay in g_NCR5380.c. Better do this before NCR5380_init() so you can probe before allocating a scsi host. Just write 0 to MODE_REG or SELECT_ENABLE_REG.
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);
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(+)