Re: [PATCH 2/4] vfio: platform: reset: calxedaxgmac: add reset function registration

From: Arnd Bergmann
Date: Mon Oct 19 2015 - 09:25:28 EST


On Monday 19 October 2015 15:17:30 Eric Auger wrote:
> Hi Arnd,
> On 10/19/2015 03:04 PM, Arnd Bergmann wrote:
> > On Sunday 18 October 2015 18:00:13 Eric Auger wrote:
> >> diff --git a/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c b/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
> >> index 619dc7d..4f76b17 100644
> >> --- a/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
> >> +++ b/drivers/vfio/platform/reset/vfio_platform_calxedaxgmac.c
> >> @@ -29,8 +29,7 @@
> >> #define DRIVER_VERSION "0.1"
> >> #define DRIVER_AUTHOR "Eric Auger <eric.auger@xxxxxxxxxx>"
> >> #define DRIVER_DESC "Reset support for Calxeda xgmac vfio platform device"
> >> -
> >> -#define CALXEDAXGMAC_COMPAT "calxeda,hb-xgmac"
> >> +#define COMPAT "calxeda,hb-xgmac"
> >
> > Why the rename?
> This define was not used. Since the code is meant to be duplicated from
> one reset module to the other I thought it did not bring any have a
> specialized name

I'd say it would be clearer to remove the macro then, and pass the
string literal in the function call.

> >> /* XGMAC Register definitions */
> >> #define XGMAC_CONTROL 0x00000000 /* MAC Configuration */
> >> @@ -80,6 +79,43 @@ int vfio_platform_calxedaxgmac_reset(struct vfio_platform_device *vdev)
> >> }
> >> EXPORT_SYMBOL_GPL(vfio_platform_calxedaxgmac_reset);
> >>
> >> +static int __init vfio_platform_calxedaxgmac_init(void)
> >> +{
> >> + int (*register_reset)(struct module *, char*,
> >> + vfio_platform_reset_fn_t);
> >> + int ret;
> >> +
> >> + register_reset = symbol_get(vfio_platform_register_reset);
> >> + if (!register_reset)
> >> + return -EINVAL;
> >
> > I don't understand what you do the symbol_get() here for.
> > Why not just call that function directly
> the function is implemented in a separate module. This is just to make
> sure the vfio-platform module is loaded, in case the end-user attempts
> to load the reset module without having this latter loaded.

The module loader does all this for you.

Arnd
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