RE: [PATCH 3/4 v2] libertas: implement function init/shutdown commands for SD8688

[Marcel Holtmann <marcel@holtmann.org>]

Hi Bing,

> > > SD8688 is a WLAN/Bluetooth combo chip and both functions are supported
> > > in a single firmware image. FUNC_INIT and FUNC_SHUTDOWN commands are
> > > implemented to utilize the multiple function feature.
> > >
> > > When SD8688 card is inserted, the firmware image should be downloaded
> > > only once through either WLAN function (Libertas driver) or Bluetooth
> > > function (Bluetooth driver).
> > >
> > > This patch adds function init/shutdown for SD8688 WLAN function only.
> > >
> > > Signed-off-by: Bing Zhao <bzhao@marvell.com>
> > > ---
> > >  drivers/net/wireless/libertas/host.h    |    2 +
> > >  drivers/net/wireless/libertas/if_sdio.c |   43 +++++++++++++++++++++++++++++-
> > >  2 files changed, 43 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/net/wireless/libertas/host.h b/drivers/net/wireless/libertas/host.h
> > > index 8ff8ac9..fe8f0cb 100644
> > > --- a/drivers/net/wireless/libertas/host.h
> > > +++ b/drivers/net/wireless/libertas/host.h
> > > @@ -86,6 +86,8 @@
> > >  #define CMD_MESH_CONFIG_OLD			0x00a3
> > >  #define CMD_MESH_CONFIG				0x00ac
> > >  #define	CMD_SET_BOOT2_VER			0x00a5
> > > +#define	CMD_FUNC_INIT				0x00a9
> > > +#define	CMD_FUNC_SHUTDOWN			0x00aa
> > >  #define CMD_802_11_BEACON_CTRL			0x00b0
> > >
> > >  /* For the IEEE Power Save */
> > > diff --git a/drivers/net/wireless/libertas/if_sdio.c b/drivers/net/wireless/libertas/if_sdio.c
> > > index e998c12..84fef6b 100644
> > > --- a/drivers/net/wireless/libertas/if_sdio.c
> > > +++ b/drivers/net/wireless/libertas/if_sdio.c
> > > @@ -39,8 +39,12 @@
> > >  #include "decl.h"
> > >  #include "defs.h"
> > >  #include "dev.h"
> > > +#include "cmd.h"
> > >  #include "if_sdio.h"
> > >
> > > +/* set this flag in if_sdio_exit_module() if user removes this module */
> > > +static u8 user_rmmod;
> > > +
> > 
> > what is this suppose to be doing? There is no description in the commit
> > messages or the code. And it looks pretty hackish to me.
>
> I'm using this flag as the indication of module removal.
> 
> I have to distinguish these scenarios and handle them differently:
> (1) user unplugs the card: As the card is unplugged, there is no way (no need) to send SHUTDOWN command.
> (2) user removes the libertas_sdio module manually: Since the card is still in the slot, SHUTDOWN command will be sent to firmware.
> 
> When user rmmod the module, if_sdio_exit_module() is called and this flag "user_rmmod" is set to 1. When if_sdio_remove() is called this flag will be used to determine whether the SHUTDOWN command should be sent or not.
> 
> I hesitated to use this global variable in such a weird way. But I couldn't think of a better solution.

I still don't see why this is needed. The rmmod should trigger the
driver removal and you can do cleanup via the removal callback. I do
might be missing something essential here, but I have never seen any
driver needing such a weird hack.

Regards

Marcel