Re: [PATCH v1 2/3] lib: bootstrap: detect SD card before mounting

[Sascha Hauer <s.hauer@pengutronix.de>]

On Thu, Jan 03, 2019 at 08:53:18PM +0100, Sam Ravnborg wrote:
> Hi Andreay.
> 
> > > > To support bootstrap from SD card run a detect all before
> > > > mounting the SD card.
> > > >
> > > > Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> > > > ---
> > > >  lib/bootstrap/disk.c | 2 ++
> > > >  1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/lib/bootstrap/disk.c b/lib/bootstrap/disk.c
> > > > index fd016166e..77be95c2f 100644
> > > > --- a/lib/bootstrap/disk.c
> > > > +++ b/lib/bootstrap/disk.c
> > > > @@ -21,6 +21,8 @@ void* bootstrap_read_disk(const char *dev, const char *fstype)
> > > >         size_t len;
> > > >         const char *path = "/";
> > > >
> > > > +       device_detect_all();
> > > > +
> > > 
> > > Can device_detect_by_name(dev) be used here instead?
> > 
> > dev equals "disk0.0" when we call bootstrap_read_disk().
> > Calling device_detect_by_name("disk0.0") did not work, and then
> > the easy solution with device_detect_all() worked.
> > 
> > I could pass the dev name to bootstrap_read_disk() but
> > this would make the caller less general which is why I ended
> > up with the more brutal solution.
> 
> I ended up with following code in arch/arm/boards/at91sam9263ek/init.c:
> #if defined(CONFIG_MCI_ATMEL)
> static struct atmel_mci_platform_data __initdata ek_mci_data = {
>         .devname        = "disk0",
>         .bus_width      = 4,
>         .detect_pin     = AT91_PIN_PE18,
>         .wp_pin         = AT91_PIN_PE19,
> };
> 
> When I specify "devname=disk0", then I could use
> detect_by_name(dev) in bootstrap_read_disk().
> No too pretty, but preferable compared to
> running a loop detecting all devices.

There are two other possibilities. First there is CONFIG_MCI_STARTUP
which causes the SD cards to be detected during host registration.
Another possibility would be to call device_detect_by_name() from board
code (where you implicitly know which hardware device to probe)

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

_______________________________________________
barebox mailing list
barebox@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/barebox