VideoCore reports garbage in viewport geometry fields unless
viewport was set previously by earlier stage boot loader. So
when booting FreeBSD kernel directly from VideoCore's start.elf
framebuffer intialization fails due to invalid vxres, vyres
values. Make sure we request viewport to be equal to physical
resolution
Submitted by: Sylvain Garrigues <sylvain@sylvaingarrigues.com>
- Add bcm2835_mbox_property for generic property request, it accepts
pointer to prepared property chan message and its size, forwards
it to MBOX and copies result back
- Make all bcm2835_mbox_XXX functions that use property channel go
through bcm2835_mbox_property path. Do not accept device_t as
an argument, it's not required: all DMA operatiosn should go
through mbox device, and all API consumers should report errors
on their side.
BCM2835_MBOX_CHAN_PROP channel. The old channel (BCM2835_MBOX_CHAN_FB)
seems deprecated on recent firmware versions and is causing a freeze on
RPi 2.
The actual changes in the framebuffer drivers will follow in subsequent
commits.
to get the default frequency of the sdhci device.
While here use a u_int to hold the frequency as it may be too large to fit
in a 32-bit signed integer. This is the case when we have a 250MHz clock.
