Re: [PATCH] fpga fr br: fix warning for unexpected version number

[matthew . gerlach]

On Wed, 5 Apr 2017, Moritz Fischer wrote:

> Hi Matthew,

Hi Moritz,


> On Wed, Apr 5, 2017 at 12:05 PM,  <matthew.gerlach@xxxxxxxxxxxxxxx> wrote:
> > From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> >
> > The value in the version register of the altera freeze bridge
> > controller changed from the beta value of 2 to the
> > value of 0xad000003 in the official release of the IP.
> > This patch supports the old and new version numbers
> > without printing an warning.
> >
> > Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
> > ---
> >  drivers/fpga/altera-freeze-bridge.c | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/fpga/altera-freeze-bridge.c b/drivers/fpga/altera-freeze-bridge.c
> > index 8dcd9fb..bdfd5eb 100644
> > --- a/drivers/fpga/altera-freeze-bridge.c
> > +++ b/drivers/fpga/altera-freeze-bridge.c
> > @@ -28,6 +28,7 @@
> >  #define FREEZE_CSR_REG_VERSION                 12
> >
> >  #define FREEZE_CSR_SUPPORTED_VERSION           2
> > +#define FREEZE_CSR_OFFICIAL_VERSION            0xad000003
> >
> >  #define FREEZE_CSR_STATUS_FREEZE_REQ_DONE      BIT(0)
> >  #define FREEZE_CSR_STATUS_UNFREEZE_REQ_DONE    BIT(1)
> > @@ -241,10 +242,12 @@ static int altera_freeze_br_probe(struct platform_device *pdev)
> >                 priv->enable = 1;
> >
> >         revision = readl(priv->base_addr + FREEZE_CSR_REG_VERSION);
> > -       if (revision != FREEZE_CSR_SUPPORTED_VERSION)
> > +       if ((revision != FREEZE_CSR_SUPPORTED_VERSION) &&
> > +           (revision != FREEZE_CSR_OFFICIAL_VERSION))
> >                 dev_warn(dev,
> > -                        "%s Freeze Controller unexpected revision %d != %d\n",
> > -                        __func__, revision, FREEZE_CSR_SUPPORTED_VERSION);
> > +                        "%s unexpected revision 0x%x != 0x%x != 0x%x\n",
> > +                        __func__, revision, FREEZE_CSR_SUPPORTED_VERSION,
> > +                        FREEZE_CSR_OFFICIAL_VERSION);
>
> Maybe you actually wanna bail out if you read a random other value
> instead of what you
> expect instead of printing a warning.

I thought about making it an error if the version didn't match, but it was 
a dev_warn() before and that allowed folks to use the "old" driver with 
the new IP version.

> >         return fpga_bridge_register(dev, FREEZE_BRIDGE_NAME,
> >                                     &altera_freeze_br_br_ops, priv);
> > --
> > 2.7.4
>
> Cheers,
>
> Moritz