APPLIED: i2c: tegra: use repeated start for reads

I2C read transactions are typically implemented as follows:

START(write) address REPEATED_START(read) data... STOP

However, Tegra's I2C driver currently implements reads as follows:

START(write) address STOP START(read) data... STOP

This sequence confuses at least the AS3722 PMIC on the Jetson TK1 board,
leading to corrupted read data in some cases. Fix the driver to chain
the transactions together using repeated starts to solve this.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Yen Lin <yelin@nvidia.com>
APPLIED: i2c: tegra: write clean data to TX FIFO

The Tegra I2C controller's TX FIFO contains 32-bit words. If the final
FIFO entry of a transaction contains fewer than 4 bytes, the driver
currently fills the unused FIFO bytes with uninitialized data. This can
be confusing when reading back the FIFO content for debugging purposes.

Solve this by explicitly initializing the variable containing FIFO data
before filling it (partially) with data. With this change,
send_recv_packets()'s loop's if (is_write) code mirrors the else (i.e.
read) branch.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Yen Lin <yelin@nvidia.com>
APPLIED: i2c: tegra: dump alen in debug statements

Since tegra_i2c_{read,write}'s debug() call dumps the chip address, dump
the address length (alen) too, so the address value can be correctly
interpreted.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Yen Lin <yelin@nvidia.com>
ARM: tegra: enable DFU too

Enable DFU protocol support (via the "dfu" command) on Tegra boards where
USB device/gadget mode is enabled.

This relies on a number of fixes to the ci_udc HW driver and DFU protocol
code.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
TEMP HACK: enable ext4 write for DFU testing
LOCAL: test: dfu: reduce max test binary size

Tegra's DFU buffer is smaller than 8M. Remove that test case since we
know it will fail.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
FIXME: BOOTP retry timeout improvements

Signed-off-by: Stephen Warren <swarren@nvidia.com>
ARM: tegra: Disable VPR

On Tegra114 and Tegra124 platforms, certain display-related registers cannot
be accessed unless the VPR registers are programmed.  For bootloader, we
probably don't care about VPR, so we disable it (which counts as programming
it, and allows those display-related registers to be accessed.

This patch is based on the commit 5f499646c83ba08079f3fdff6591f638a0ce4c0c
in Chromium OS U-Boot project.

Signed-off-by: Andrew Chew <achew@nvidia.com>
Signed-off-by: Jimmy Zhang <jimmzhang@nvidia.com>
Signed-off-by: Bryan Wu <pengw@nvidia.com>
[acourbot: ensure write went through, vpr.c style changes]
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Cc: Tom Warren <TWarren@nvidia.com>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Terje Bergstrom <tbergstrom@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
ARM: tegra: Use mem size from MC rather than ODMDATA

In at least Tegra124, the Tegra memory controller (MC) has a register
that controls the memory size. Read this to determine the memory size
rather than requiring this to be redundantly encoded into the ODMDATA.
This way, changes to the BCT (i.e. MC configuration) automatically
updated SW's view of the memory size, without requiring manual changes
to the ODMDATA.

Future work potentially required:
* Clip the memory size to architectural limits; U-Boot probably doesn't
  and won't support either LPAE or Tegra's "swiss cheese" memory layout,
  at least one of which would be required for >2GB RAM.
* Subtract out any carveout required by firmware on future SoCs.

Based-on-work-by: Tom Warren <twarren@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
Note: this patch depends on Bryan's/Alex's "ARM: tegra: Disable VPR",
since that introduces mc.h, which this patch relies on.