ARM: bcm2835: add mailbox driver

The BCM2835 SoC contains (at least) two CPUs; the VideoCore (a/k/a "GPU")
and the ARM CPU. The ARM CPU is often thought of as the main CPU.
However, the VideoCore actually controls the initial SoC boot, and hides
much of the hardware behind a protocol. This protocol is transported
using the SoC's mailbox hardware module.

Here, we add a very simplistic driver for the mailbox module, and define
a few structures for the property messages.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
v3: Re-license to GPL-v2 or later.
v2:
* Added documentation to mbox.h.
* Implemented macros to set up headers and tags.
* Implemented error-checking of response bits in bcm2835_mbox_call_prop().
* Reworked tag structs based on experience writing LCD driver.
* Added a lot more video-related tag structs.
* Added debug spew and error messages to mbox.c; useful when debugging LCD.
* Removed __packed attributes from message structs.
* Removed stale FIXME comments.
ARM: rpi_b: use bcm2835 mbox driver to get memory size

The firmware running on the bcm2835 SoC's VideoCore CPU determines how
much of the system RAM is available for use by the ARM CPU. Previously,
U-Boot assumed that only 128MB was available, since this was the
smallest value configured by any public firmware. However, we can now
query the actual value at run-time from the firmware using the mbox
property protocol.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
v3: No change.
v2: Updated to use macros etc. added in v2 of mbox driver patch.
lcd: calculate line_length after lcd_ctrl_init()

When an LCD driver is actually driving a regular external display, e.g.
an HDMI monitor, the display resolution might not be known until the
display controller has initialized, i.e. during lcd_ctrl_init(). However,
lcd.c calculates lcd_line_length before calling this function, thus
relying on a hard-coded resolution in struct panel_info.

Instead, defer this calculation until after lcd_ctrl_init() has had the
chance to dynamically determine the resolution. This needs to happen
before lcd_clear(), since the value is used there.

grep indicates that no code outside lcd.c uses this lcd_line_length; in
particular, no lcd_ctrl_init() implementations read it.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
--
v3: No change.
video: add a driver for the bcm2835

The firmware running on the bcm2835 SoC's VideoCore CPU manages the
display controller. Add a simple "LCD" driver that communicates with the
firmware using the property mailbox protocol. This configures the
display and frame-buffer to match whatever physical resolution the
firmware chosen when booting, which is typically the native resolution
of the attached display device, presumably unless otherwise specified
in config.txt on the boot media.

Enable this driver in the Raspberry Pi board configuration.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
v3: Re-license to GPL-v2 or later. Fix typo in commit description.
v2: New patch.
mmc: add bcm2835 driver

This adds a simple driver for the BCM2835's SD controller.

Workarounds are implemented for:
* Register writes can't be too close to each-other in time, or they will
  be lost.
* Register accesses must all be 32-bit, so implement custom accessors.

This code was extracted from:
git://github.com/gonzoua/u-boot-pi.git master
which was created by Oleksandr Tymoshenko.

Portions of the code there were obviously based on the Linux kernel at:
git://github.com/raspberrypi/linux.git rpi-3.6.y
commit f5b930b "Main bcm2708 linux port" signed-off-by Dom Cobley.

swarren changed the following for upstream:
* Removed hack udelay()s in bcm2835_sdhci_raw_writel(); setting
  SDHCI_QUIRK_WAIT_SEND_CMD appears to solve the issues.
* Remove register logging from read*/write* functions.
* Sort out confusion with min/max_freq values passed to add_sdhci().
* Use more descriptive variable names and calculations in IO accessors.
* Simplified and commented twoticks_delay calculation.
* checkpatch fixes.

Signed-off-by: Oleksandr Tymoshenko <gonzo@bluezbox.com>
Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
---
v2:
* Use more descriptive variable names and calculations in IO accessors.
* Add Oleksandr's S-o-b.
* Rewrite commit description to note that the Linux code this was derived
  from was S-o-b Dom Cobley.
ARM: rpi_b: enable SD controller, add related env/cmds

Enable the SD controller driver for the Raspberry Pi. Enable a number
of useful MMC, partition, and filesystem-related commands. Set up the
environment to provide standard locations for loading a kernel, DTB,
etc. Provide a boot command that loads and executes boot.scr.uimg from
the SD card; this is written considering future extensibilty to USB
storage.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
ARM: rpi_b: attempt to turn on power to SD controller

This can't be done yet: The firmware gives an error reponse to
set_power_state. See:
https://github.com/raspberrypi/firmware/issues/106

However, this isn't needed in practice, since the boot firmware must
have turned on the power itself, since it loaded U-Boot from the SD
card.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>