In U-Boot it is pretty common to number devices from 0 and access them
on the command line using this numbering. While it may come to pass that
we will move away from this numbering, the possibility seems remote at
present.
Given that devices within a uclass will have an implied numbering, it
makes sense to build this into driver model as a core feature. The cost
is fairly small in terms of code and data space.
With each uclass having numbered devices we can ask for SPI port 0 or
serial port 1 and receive a single device.
Devices typically request a sequence number using aliases in the device
tree. These are resolved when the device is probed, to deal with conflicts.
Sequence numbers need not be sequential and holes are permitted.
At present there is no support for sequence numbers using static platform
data. It could easily be added to 'struct driver_info' if needed, but it
seems better to add features as we find a use for them, and the use of -1
to mean 'no sequence' makes the default value somewhat painful.
Signed-off-by: Simon Glass <sjg@chromium.org>
#
# Xilinx ZYNQ U-Boot
#
# (C) Copyright 2013 Xilinx, Inc.
#
# SPDX-License-Identifier: GPL-2.0+
#
1. About this
This document describes the information about Xilinx Zynq U-Boot -
like supported boards, ML status and TODO list.
2. Zynq boards
Xilinx Zynq-7000 All Programmable SoCs enable extensive system level
differentiation, integration, and flexibility through hardware, software,
and I/O programmability.
* zc70x
- zc702 (single qspi, gem0, mmc) [1]
- zc706 (dual parallel qspi, gem0, mmc) [2]
* zed (single qspi, gem0, mmc) [3]
* microzed (single qspi, gem0, mmc) [4]
* zc770
- zc770-xm010 (single qspi, gem0, mmc)
- zc770-xm011 (8 or 16 bit nand)
- zc770-xm012 (nor)
- zc770-xm013 (dual parallel qspi, gem1)
3. Building
# Configure for zc70x board
$ make zynq_zc70x_config
Configuring for zynq_zc70x board...
# Building default dts for zc702 board
$ make
# Building specified dts for zc706 board
$ make DEVICE_TREE=zynq-zc706
4. Bootmode
Zynq has a facility to read the bootmode from the slcr bootmode register
once user is setting through jumpers on the board - see page no:1546 on [5]
All possible bootmode values are defined in Table 6-2:Boot_Mode MIO Pins
on [5].
board_late_init() will read the bootmode values using slcr bootmode register
at runtime and assign the modeboot variable to specific bootmode string which
is intern used in autoboot.
SLCR bootmode register Bit[3:0] values
#define ZYNQ_BM_NOR 0x02
#define ZYNQ_BM_SD 0x05
#define ZYNQ_BM_JTAG 0x0
"modeboot" variable can assign any of "norboot", "sdboot" or "jtagboot"
bootmode strings at runtime.
5. Mainline status
- Added basic board configurations support.
- Added zynq u-boot bsp code - arch/arm/cpu/armv7/zynq
- Added zynq boards named - zc70x, zed, microzed, zc770_xm010, zc770_xm012, zc770_xm013
- Added zynq drivers:
serial - drivers/serial/serial_zynq.c
net - drivers/net/zynq_gem.c
mmc - drivers/mmc/zynq_sdhci.c
mmc - drivers/mmc/zynq_sdhci.c
spi- drivers/spi/zynq_spi.c
i2c - drivers/i2c/zynq_i2c.c
- Done proper cleanups on board configurations
- Added basic FDT support for zynq boards
- d-cache support for zynq_gem.c
6. TODO
- Add zynq boards support - zc770_xm011
- Add zynq qspi controller driver
- Add zynq nand controller driver
- Add FDT support on individual drivers
[1] http://www.xilinx.com/products/boards-and-kits/EK-Z7-ZC702-G.htm
[2] http://www.xilinx.com/products/boards-and-kits/EK-Z7-ZC706-G.htm
[3] http://zedboard.org/product/zedboard
[4] http://zedboard.org/product/microzed
[5] http://www.xilinx.com/support/documentation/user_guides/ug585-Zynq-7000-TRM.pdf
--
Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Sun Dec 15 14:52:41 IST 2013
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