omap3evm: Add CONFIG_CMD_ASKENV

[karo-tx-uboot.git] / README

diff --git a/README b/README
index 7e032a91bef53f0577a5730ad8406619058c9b5d..67dc444bd4d0bbe92d2cefcf45b220d079f98c37 100644 (file)
--- a/README
+++ b/README
@@ -1,5 +1,5 @@
 #
 #

-# (C) Copyright 2000 - 2011
+# (C) Copyright 2000 - 2012

 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 #
 # See file CREDITS for list of people who contributed to this
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 #
 # See file CREDITS for list of people who contributed to this


@@ -134,7 +134,7 @@ Additional fields (if present) indicate release candidates or bug fix
 releases in "stable" maintenance trees.
 
 Examples:
 releases in "stable" maintenance trees.
 
 Examples:

-       U-Boot v2009.11     - Release November 2009
+       U-Boot v2009.11     - Release November 2009

        U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
        U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
 
        U-Boot v2009.11.1   - Release 1 in version November 2009 stable tree
        U-Boot v2010.09-rc1 - Release candiate 1 for September 2010 release
 


@@ -183,6 +183,10 @@ Directory Hierarchy:
       /mips32          Files specific to MIPS32 CPUs
       /xburst          Files specific to Ingenic XBurst CPUs
     /lib               Architecture specific library files
       /mips32          Files specific to MIPS32 CPUs
       /xburst          Files specific to Ingenic XBurst CPUs
     /lib               Architecture specific library files

+  /nds32               Files generic to NDS32 architecture
+    /cpu               CPU specific files
+      /n1213           Files specific to Andes Technology N1213 CPUs
+    /lib               Architecture specific library files

   /nios2               Files generic to Altera NIOS2 architecture
     /cpu               CPU specific files
     /lib               Architecture specific library files
   /nios2               Files generic to Altera NIOS2 architecture
     /cpu               CPU specific files
     /lib               Architecture specific library files


@@ -370,6 +374,12 @@ The following options need to be configured:
                Defines the string to utilize when trying to match PCIe device
                tree nodes for the given platform.
 
                Defines the string to utilize when trying to match PCIe device
                tree nodes for the given platform.
 

+- Generic CPU options:
+               CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN
+
+               Defines the endianess of the CPU. Implementation of those
+               values is arch specific.
+

 - Intel Monahans options:
                CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
 
 - Intel Monahans options:
                CONFIG_SYS_MONAHANS_RUN_MODE_OSC_RATIO
 


@@ -416,6 +426,20 @@ The following options need to be configured:
                XWAY SoCs for booting from NOR flash. The U-Boot image needs to
                be swapped if a flash programmer is used.
 
                XWAY SoCs for booting from NOR flash. The U-Boot image needs to
                be swapped if a flash programmer is used.
 

+- ARM options:
+               CONFIG_SYS_EXCEPTION_VECTORS_HIGH
+
+               Select high exception vectors of the ARM core, e.g., do not
+               clear the V bit of the c1 register of CP15.
+
+               CONFIG_SYS_THUMB_BUILD
+
+               Use this flag to build U-Boot using the Thumb instruction
+               set for ARM architectures. Thumb instruction set provides
+               better code density. For ARM architectures that support
+               Thumb2 this flag will result in Thumb2 code generated by
+               GCC.
+

 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 
 - Linux Kernel Interface:
                CONFIG_CLOCKS_IN_MHZ
 


@@ -560,7 +584,7 @@ The following options need to be configured:
 
                CONFIG_CFB_CONSOLE
                Enables console device for a color framebuffer. Needs following
 
                CONFIG_CFB_CONSOLE
                Enables console device for a color framebuffer. Needs following

-               defines (cf. smiLynxEM, i8042, board/eltec/bab7xx)
+               defines (cf. smiLynxEM, i8042)

                        VIDEO_FB_LITTLE_ENDIAN  graphic memory organisation
                                                (default big endian)
                        VIDEO_HW_RECTFILL       graphic chip supports
                        VIDEO_FB_LITTLE_ENDIAN  graphic memory organisation
                                                (default big endian)
                        VIDEO_HW_RECTFILL       graphic chip supports


@@ -634,6 +658,15 @@ The following options need to be configured:
                'Sane' compilers will generate smaller code if
                CONFIG_PRE_CON_BUF_SZ is a power of 2
 
                'Sane' compilers will generate smaller code if
                CONFIG_PRE_CON_BUF_SZ is a power of 2
 

+- Safe printf() functions
+               Define CONFIG_SYS_VSNPRINTF to compile in safe versions of
+               the printf() functions. These are defined in
+               include/vsprintf.h and include snprintf(), vsnprintf() and
+               so on. Code size increase is approximately 300-500 bytes.
+               If this option is not given then these functions will
+               silently discard their buffer size argument - this means
+               you are not getting any overflow checking in this case.
+

 - Boot Delay:  CONFIG_BOOTDELAY - in seconds
                Delay before automatically booting the default image;
                set to -1 to disable autoboot.
 - Boot Delay:  CONFIG_BOOTDELAY - in seconds
                Delay before automatically booting the default image;
                set to -1 to disable autoboot.


@@ -752,6 +785,8 @@ The following options need to be configured:
                CONFIG_CMD_JFFS2        * JFFS2 Support
                CONFIG_CMD_KGDB         * kgdb
                CONFIG_CMD_LDRINFO        ldrinfo (display Blackfin loader)
                CONFIG_CMD_JFFS2        * JFFS2 Support
                CONFIG_CMD_KGDB         * kgdb
                CONFIG_CMD_LDRINFO        ldrinfo (display Blackfin loader)

+               CONFIG_CMD_LINK_LOCAL   * link-local IP address auto-configuration
+                                         (169.254.*.*)

                CONFIG_CMD_LOADB          loadb
                CONFIG_CMD_LOADS          loads
                CONFIG_CMD_MD5SUM         print md5 message digest
                CONFIG_CMD_LOADB          loadb
                CONFIG_CMD_LOADS          loads
                CONFIG_CMD_MD5SUM         print md5 message digest


@@ -765,7 +800,7 @@ The following options need to be configured:
                CONFIG_CMD_NAND         * NAND support
                CONFIG_CMD_NET            bootp, tftpboot, rarpboot
                CONFIG_CMD_PCA953X      * PCA953x I2C gpio commands
                CONFIG_CMD_NAND         * NAND support
                CONFIG_CMD_NET            bootp, tftpboot, rarpboot
                CONFIG_CMD_PCA953X      * PCA953x I2C gpio commands

-               CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command
+               CONFIG_CMD_PCA953X_INFO * PCA953x I2C gpio info command

                CONFIG_CMD_PCI          * pciinfo
                CONFIG_CMD_PCMCIA               * PCMCIA support
                CONFIG_CMD_PING         * send ICMP ECHO_REQUEST to network
                CONFIG_CMD_PCI          * pciinfo
                CONFIG_CMD_PCMCIA               * PCMCIA support
                CONFIG_CMD_PING         * send ICMP ECHO_REQUEST to network


@@ -779,15 +814,17 @@ The following options need to be configured:
                                          (requires CONFIG_CMD_I2C)
                CONFIG_CMD_SETGETDCR      Support for DCR Register access
                                          (4xx only)
                                          (requires CONFIG_CMD_I2C)
                CONFIG_CMD_SETGETDCR      Support for DCR Register access
                                          (4xx only)

+               CONFIG_CMD_SF           * Read/write/erase SPI NOR flash

                CONFIG_CMD_SHA1SUM        print sha1 memory digest
                                          (requires CONFIG_CMD_MEMORY)
                CONFIG_CMD_SOURCE         "source" command Support
                CONFIG_CMD_SPI          * SPI serial bus support
                CONFIG_CMD_TFTPSRV      * TFTP transfer in server mode
                CONFIG_CMD_SHA1SUM        print sha1 memory digest
                                          (requires CONFIG_CMD_MEMORY)
                CONFIG_CMD_SOURCE         "source" command Support
                CONFIG_CMD_SPI          * SPI serial bus support
                CONFIG_CMD_TFTPSRV      * TFTP transfer in server mode

+               CONFIG_CMD_TFTPPUT      * TFTP put command (upload)

                CONFIG_CMD_TIME         * run command and report execution time
                CONFIG_CMD_USB          * USB support
                CONFIG_CMD_CDP          * Cisco Discover Protocol support
                CONFIG_CMD_TIME         * run command and report execution time
                CONFIG_CMD_USB          * USB support
                CONFIG_CMD_CDP          * Cisco Discover Protocol support

-               CONFIG_CMD_FSL          * Microblaze FSL support
+               CONFIG_CMD_MFSL         * Microblaze FSL support

 
 
                EXAMPLE: If you want all functions except of network
 
 
                EXAMPLE: If you want all functions except of network


@@ -811,6 +848,36 @@ The following options need to be configured:
 
                XXX - this list needs to get updated!
 
 
                XXX - this list needs to get updated!
 

+- Device tree:
+               CONFIG_OF_CONTROL
+               If this variable is defined, U-Boot will use a device tree
+               to configure its devices, instead of relying on statically
+               compiled #defines in the board file. This option is
+               experimental and only available on a few boards. The device
+               tree is available in the global data as gd->fdt_blob.
+
+               U-Boot needs to get its device tree from somewhere. This can
+               be done using one of the two options below:
+
+               CONFIG_OF_EMBED
+               If this variable is defined, U-Boot will embed a device tree
+               binary in its image. This device tree file should be in the
+               board directory and called <soc>-<board>.dts. The binary file
+               is then picked up in board_init_f() and made available through
+               the global data structure as gd->blob.
+
+               CONFIG_OF_SEPARATE
+               If this variable is defined, U-Boot will build a device tree
+               binary. It will be called u-boot.dtb. Architecture-specific
+               code will locate it at run-time. Generally this works by:
+
+                       cat u-boot.bin u-boot.dtb >image.bin
+
+               and in fact, U-Boot does this for you, creating a file called
+               u-boot-dtb.bin which is useful in the common case. You can
+               still use the individual files if you need something more
+               exotic.
+

 - Watchdog:
                CONFIG_WATCHDOG
                If this variable is defined, it enables watchdog
 - Watchdog:
                CONFIG_WATCHDOG
                If this variable is defined, it enables watchdog


@@ -841,7 +908,7 @@ The following options need to be configured:
 
                CONFIG_RTC_MPC8xx       - use internal RTC of MPC8xx
                CONFIG_RTC_PCF8563      - use Philips PCF8563 RTC
 
                CONFIG_RTC_MPC8xx       - use internal RTC of MPC8xx
                CONFIG_RTC_PCF8563      - use Philips PCF8563 RTC

-               CONFIG_RTC_MC13783      - use MC13783 RTC
+               CONFIG_RTC_MC13XXX      - use MC13783 or MC13892 RTC

                CONFIG_RTC_MC146818     - use MC146818 RTC
                CONFIG_RTC_DS1307       - use Maxim, Inc. DS1307 RTC
                CONFIG_RTC_DS1337       - use Maxim, Inc. DS1337 RTC
                CONFIG_RTC_MC146818     - use MC146818 RTC
                CONFIG_RTC_DS1307       - use Maxim, Inc. DS1307 RTC
                CONFIG_RTC_DS1337       - use Maxim, Inc. DS1337 RTC


@@ -922,7 +989,20 @@ The following options need to be configured:
 
 - NETWORK Support (PCI):
                CONFIG_E1000
 
 - NETWORK Support (PCI):
                CONFIG_E1000

-               Support for Intel 8254x gigabit chips.
+               Support for Intel 8254x/8257x gigabit chips.
+
+               CONFIG_E1000_SPI
+               Utility code for direct access to the SPI bus on Intel 8257x.
+               This does not do anything useful unless you set at least one
+               of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC.
+
+               CONFIG_E1000_SPI_GENERIC
+               Allow generic access to the SPI bus on the Intel 8257x, for
+               example with the "sspi" command.
+
+               CONFIG_CMD_E1000
+               Management command for E1000 devices.  When used on devices
+               with SPI support you can reprogram the EEPROM from U-Boot.

 
                CONFIG_E1000_FALLBACK_MAC
                default MAC for empty EEPROM after production.
 
                CONFIG_E1000_FALLBACK_MAC
                default MAC for empty EEPROM after production.


@@ -955,6 +1035,9 @@ The following options need to be configured:
                        If this defined, the driver is quiet.
                        The driver doen't show link status messages.
 
                        If this defined, the driver is quiet.
                        The driver doen't show link status messages.
 

+               CONFIG_CALXEDA_XGMAC
+               Support for the Calxeda XGMAC device
+

                CONFIG_DRIVER_LAN91C96
                Support for SMSC's LAN91C96 chips.
 
                CONFIG_DRIVER_LAN91C96
                Support for SMSC's LAN91C96 chips.
 


@@ -979,6 +1062,12 @@ The following options need to be configured:
                        Define this to use i/o functions instead of macros
                        (some hardware wont work with macros)
 
                        Define this to use i/o functions instead of macros
                        (some hardware wont work with macros)
 

+               CONFIG_DRIVER_TI_EMAC
+               Support for davinci emac
+
+                       CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT
+                       Define this if you have more then 3 PHYs.
+

                CONFIG_FTGMAC100
                Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
 
                CONFIG_FTGMAC100
                Support for Faraday's FTGMAC100 Gigabit SoC Ethernet
 


@@ -1018,6 +1107,16 @@ The following options need to be configured:
                        CONFIG_SH_ETHER_CACHE_WRITEBACK
                        If this option is set, the driver enables cache flush.
 
                        CONFIG_SH_ETHER_CACHE_WRITEBACK
                        If this option is set, the driver enables cache flush.
 

+- TPM Support:
+               CONFIG_GENERIC_LPC_TPM
+               Support for generic parallel port TPM devices. Only one device
+               per system is supported at this time.
+
+                       CONFIG_TPM_TIS_BASE_ADDRESS
+                       Base address where the generic TPM device is mapped
+                       to. Contemporary x86 systems usually map it at
+                       0xfed40000.
+

 - USB Support:
                At the moment only the UHCI host controller is
                supported (PIP405, MIP405, MPC5200); define
 - USB Support:
                At the moment only the UHCI host controller is
                supported (PIP405, MIP405, MPC5200); define


@@ -1042,6 +1141,9 @@ The following options need to be configured:
                                May be defined to allow interrupt polling
                                instead of using asynchronous interrupts
 
                                May be defined to allow interrupt polling
                                instead of using asynchronous interrupts
 

+               CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the
+               txfilltuning field in the EHCI controller on reset.
+

 - USB Device:
                Define the below if you wish to use the USB console.
                Once firmware is rebuilt from a serial console issue the
 - USB Device:
                Define the below if you wish to use the USB console.
                Once firmware is rebuilt from a serial console issue the


@@ -1065,6 +1167,14 @@ The following options need to be configured:
                        Define this to have a tty type of device available to
                        talk to the UDC device
 
                        Define this to have a tty type of device available to
                        talk to the UDC device
 

+                       CONFIG_USBD_HS
+                       Define this to enable the high speed support for usb
+                       device and usbtty. If this feature is enabled, a routine
+                       int is_usbd_high_speed(void)
+                       also needs to be defined by the driver to dynamically poll
+                       whether the enumeration has succeded at high speed or full
+                       speed.
+

                        CONFIG_SYS_CONSOLE_IS_IN_ENV
                        Define this if you want stdin, stdout &/or stderr to
                        be set to usbtty.
                        CONFIG_SYS_CONSOLE_IS_IN_ENV
                        Define this if you want stdin, stdout &/or stderr to
                        be set to usbtty.


@@ -1104,6 +1214,14 @@ The following options need to be configured:
                        for your device
                        - CONFIG_USBD_PRODUCTID 0xFFFF
 
                        for your device
                        - CONFIG_USBD_PRODUCTID 0xFFFF
 

+- ULPI Layer Support:
+               The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via
+               the generic ULPI layer. The generic layer accesses the ULPI PHY
+               via the platform viewport, so you need both the genric layer and
+               the viewport enabled. Currently only Chipidea/ARC based
+               viewport is supported.
+               To enable the ULPI layer support, define CONFIG_USB_ULPI and
+               CONFIG_USB_ULPI_VIEWPORT in your board configuration file.

 
 - MMC Support:
                The MMC controller on the Intel PXA is supported. To
 
 - MMC Support:
                The MMC controller on the Intel PXA is supported. To


@@ -1140,6 +1258,15 @@ The following options need to be configured:
                to disable the command chpart. This is the default when you
                have not defined a custom partition
 
                to disable the command chpart. This is the default when you
                have not defined a custom partition
 

+- FAT(File Allocation Table) filesystem write function support:
+               CONFIG_FAT_WRITE
+
+               Define this to enable support for saving memory data as a
+               file in FAT formatted partition.
+
+               This will also enable the command "fatwrite" enabling the
+               user to write files to FAT.
+

 - Keyboard Support:
                CONFIG_ISA_KEYBOARD
 
 - Keyboard Support:
                CONFIG_ISA_KEYBOARD
 


@@ -1392,18 +1519,37 @@ The following options need to be configured:
                Define a default value for the IP address to use for
                the default Ethernet interface, in case this is not
                determined through e.g. bootp.
                Define a default value for the IP address to use for
                the default Ethernet interface, in case this is not
                determined through e.g. bootp.

+               (Environment variable "ipaddr")

 
 - Server IP address:
                CONFIG_SERVERIP
 
                Defines a default value for the IP address of a TFTP
                server to contact when using the "tftboot" command.
 
 - Server IP address:
                CONFIG_SERVERIP
 
                Defines a default value for the IP address of a TFTP
                server to contact when using the "tftboot" command.

+               (Environment variable "serverip")

 
                CONFIG_KEEP_SERVERADDR
 
                Keeps the server's MAC address, in the env 'serveraddr'
                for passing to bootargs (like Linux's netconsole option)
 
 
                CONFIG_KEEP_SERVERADDR
 
                Keeps the server's MAC address, in the env 'serveraddr'
                for passing to bootargs (like Linux's netconsole option)
 

+- Gateway IP address:
+               CONFIG_GATEWAYIP
+
+               Defines a default value for the IP address of the
+               default router where packets to other networks are
+               sent to.
+               (Environment variable "gatewayip")
+
+- Subnet mask:
+               CONFIG_NETMASK
+
+               Defines a default value for the subnet mask (or
+               routing prefix) which is used to determine if an IP
+               address belongs to the local subnet or needs to be
+               forwarded through a router.
+               (Environment variable "netmask")
+

 - Multicast TFTP Mode:
                CONFIG_MCAST_TFTP
 
 - Multicast TFTP Mode:
                CONFIG_MCAST_TFTP
 


@@ -1448,10 +1594,17 @@ The following options need to be configured:
                CONFIG_BOOTP_NTPSERVER
                CONFIG_BOOTP_TIMEOFFSET
                CONFIG_BOOTP_VENDOREX
                CONFIG_BOOTP_NTPSERVER
                CONFIG_BOOTP_TIMEOFFSET
                CONFIG_BOOTP_VENDOREX

+               CONFIG_BOOTP_MAY_FAIL

 
                CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
                environment variable, not the BOOTP server.
 
 
                CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip
                environment variable, not the BOOTP server.
 

+               CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found
+               after the configured retry count, the call will fail
+               instead of starting over.  This can be used to fail over
+               to Link-local IP address configuration if the DHCP server
+               is not available.
+

                CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
                serverip from a DHCP server, it is possible that more
                than one DNS serverip is offered to the client.
                CONFIG_BOOTP_DNS2 - If a DHCP client requests the DNS
                serverip from a DHCP server, it is possible that more
                than one DNS serverip is offered to the client.


@@ -1482,6 +1635,14 @@ The following options need to be configured:
                the DHCP timeout and retry process takes a longer than
                this delay.
 
                the DHCP timeout and retry process takes a longer than
                this delay.
 

+ - Link-local IP address negotiation:
+               Negotiate with other link-local clients on the local network
+               for an address that doesn't require explicit configuration.
+               This is especially useful if a DHCP server cannot be guaranteed
+               to exist in all environments that the device must operate.
+
+               See doc/README.link-local for more information.
+

  - CDP Options:
                CONFIG_CDP_DEVICE_ID
 
  - CDP Options:
                CONFIG_CDP_DEVICE_ID
 


@@ -1690,24 +1851,24 @@ The following options need to be configured:
                CONFIG_I2C_MULTI_BUS
 
                This option allows the use of multiple I2C buses, each of which
                CONFIG_I2C_MULTI_BUS
 
                This option allows the use of multiple I2C buses, each of which

-               must have a controller.  At any point in time, only one bus is
-               active.  To switch to a different bus, use the 'i2c dev' command.
+               must have a controller.  At any point in time, only one bus is
+               active.  To switch to a different bus, use the 'i2c dev' command.

                Note that bus numbering is zero-based.
 
                CONFIG_SYS_I2C_NOPROBES
 
                This option specifies a list of I2C devices that will be skipped
                Note that bus numbering is zero-based.
 
                CONFIG_SYS_I2C_NOPROBES
 
                This option specifies a list of I2C devices that will be skipped

-               when the 'i2c probe' command is issued.  If CONFIG_I2C_MULTI_BUS
+               when the 'i2c probe' command is issued.  If CONFIG_I2C_MULTI_BUS

                is set, specify a list of bus-device pairs.  Otherwise, specify
                a 1D array of device addresses
 
                e.g.
                        #undef  CONFIG_I2C_MULTI_BUS
                is set, specify a list of bus-device pairs.  Otherwise, specify
                a 1D array of device addresses
 
                e.g.
                        #undef  CONFIG_I2C_MULTI_BUS

-                       #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}
+                       #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68}

 
                will skip addresses 0x50 and 0x68 on a board with one I2C bus
 
 
                will skip addresses 0x50 and 0x68 on a board with one I2C bus
 

-                       #define CONFIG_I2C_MULTI_BUS
+                       #define CONFIG_I2C_MULTI_BUS

                        #define CONFIG_SYS_I2C_MULTI_NOPROBES   {{0,0x50},{0,0x68},{1,0x54}}
 
                will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
                        #define CONFIG_SYS_I2C_MULTI_NOPROBES   {{0,0x50},{0,0x68},{1,0x54}}
 
                will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1


@@ -1826,13 +1987,13 @@ The following options need to be configured:
                Enables a hardware SPI driver for general-purpose reads
                and writes.  As with CONFIG_SOFT_SPI, the board configuration
                must define a list of chip-select function pointers.
                Enables a hardware SPI driver for general-purpose reads
                and writes.  As with CONFIG_SOFT_SPI, the board configuration
                must define a list of chip-select function pointers.

-               Currently supported on some MPC8xxx processors.  For an
+               Currently supported on some MPC8xxx processors.  For an

                example, see include/configs/mpc8349emds.h.
 
                CONFIG_MXC_SPI
 
                Enables the driver for the SPI controllers on i.MX and MXC
                example, see include/configs/mpc8349emds.h.
 
                CONFIG_MXC_SPI
 
                Enables the driver for the SPI controllers on i.MX and MXC

-               SoCs. Currently only i.MX31 is supported.
+               SoCs. Currently i.MX31/35/51 are supported.

 
 - FPGA Support: CONFIG_FPGA
 
 
 - FPGA Support: CONFIG_FPGA
 


@@ -2066,6 +2227,25 @@ The following options need to be configured:
                allows to read/write in Dataflash via the standard
                commands cp, md...
 
                allows to read/write in Dataflash via the standard
                commands cp, md...
 

+- Serial Flash support
+               CONFIG_CMD_SF
+
+               Defining this option enables SPI flash commands
+               'sf probe/read/write/erase/update'.
+
+               Usage requires an initial 'probe' to define the serial
+               flash parameters, followed by read/write/erase/update
+               commands.
+
+               The following defaults may be provided by the platform
+               to handle the common case when only a single serial
+               flash is present on the system.
+
+               CONFIG_SF_DEFAULT_BUS           Bus identifier
+               CONFIG_SF_DEFAULT_CS            Chip-select
+               CONFIG_SF_DEFAULT_MODE          (see include/spi.h)
+               CONFIG_SF_DEFAULT_SPEED         in Hz
+

 - SystemACE Support:
                CONFIG_SYSTEMACE
 
 - SystemACE Support:
                CONFIG_SYSTEMACE
 


@@ -2110,6 +2290,31 @@ The following options need to be configured:
                example, some LED's) on your board. At the moment,
                the following checkpoints are implemented:
 
                example, some LED's) on your board. At the moment,
                the following checkpoints are implemented:
 

+- Detailed boot stage timing
+               CONFIG_BOOTSTAGE
+               Define this option to get detailed timing of each stage
+               of the boot process.
+
+               CONFIG_BOOTSTAGE_USER_COUNT
+               This is the number of available user bootstage records.
+               Each time you call bootstage_mark(BOOTSTAGE_ID_ALLOC, ...)
+               a new ID will be allocated from this stash. If you exceed
+               the limit, recording will stop.
+
+               CONFIG_BOOTSTAGE_REPORT
+               Define this to print a report before boot, similar to this:
+
+               Timer summary in microseconds:
+                      Mark    Elapsed  Stage
+                         0          0  reset
+                 3,575,678  3,575,678  board_init_f start
+                 3,575,695         17  arch_cpu_init A9
+                 3,575,777         82  arch_cpu_init done
+                 3,659,598     83,821  board_init_r start
+                 3,910,375    250,777  main_loop
+                29,916,167 26,005,792  bootm_start
+                30,361,327    445,160  start_kernel
+

 Legacy uImage format:
 
   Arg  Where                   When
 Legacy uImage format:
 
   Arg  Where                   When


@@ -2141,7 +2346,7 @@ Legacy uImage format:
    13  common/image.c          Start multifile image verification
    14  common/image.c          No initial ramdisk, no multifile, continue.
 
    13  common/image.c          Start multifile image verification
    14  common/image.c          No initial ramdisk, no multifile, continue.
 

-   15  arch/<arch>/lib/bootm.c All preparation done, transferring control to OS
+   15  arch/<arch>/lib/bootm.c All preparation done, transferring control to OS

 
   -30  arch/powerpc/lib/board.c        Fatal error, hang the system
   -31  post/post.c             POST test failed, detected by post_output_backlog()
 
   -30  arch/powerpc/lib/board.c        Fatal error, hang the system
   -31  post/post.c             POST test failed, detected by post_output_backlog()


@@ -2305,11 +2510,29 @@ FIT uImage format:
                CONFIG_SPL
                Enable building of SPL globally.
 
                CONFIG_SPL
                Enable building of SPL globally.
 

+               CONFIG_SPL_LDSCRIPT
+               LDSCRIPT for linking the SPL binary.
+
+               CONFIG_SPL_MAX_SIZE
+               Maximum binary size (text, data and rodata) of the SPL binary.
+

                CONFIG_SPL_TEXT_BASE
                TEXT_BASE for linking the SPL binary.
 
                CONFIG_SPL_TEXT_BASE
                TEXT_BASE for linking the SPL binary.
 

-               CONFIG_SPL_LDSCRIPT
-               LDSCRIPT for linking the SPL binary.
+               CONFIG_SPL_BSS_START_ADDR
+               Link address for the BSS within the SPL binary.
+
+               CONFIG_SPL_BSS_MAX_SIZE
+               Maximum binary size of the BSS section of the SPL binary.
+
+               CONFIG_SPL_STACK
+               Adress of the start of the stack SPL will use
+
+               CONFIG_SYS_SPL_MALLOC_START
+               Starting address of the malloc pool used in SPL.
+
+               CONFIG_SYS_SPL_MALLOC_SIZE
+               The size of the malloc pool used in SPL.

 
                CONFIG_SPL_LIBCOMMON_SUPPORT
                Support for common/libcommon.o in SPL binary
 
                CONFIG_SPL_LIBCOMMON_SUPPORT
                Support for common/libcommon.o in SPL binary


@@ -2326,6 +2549,45 @@ FIT uImage format:
                CONFIG_SPL_MMC_SUPPORT
                Support for drivers/mmc/libmmc.o in SPL binary
 
                CONFIG_SPL_MMC_SUPPORT
                Support for drivers/mmc/libmmc.o in SPL binary
 

+               CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_SECTOR,
+               CONFIG_SYS_U_BOOT_MAX_SIZE_SECTORS,
+               CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION
+               Address, size and partition on the MMC to load U-Boot from
+               when the MMC is being used in raw mode.
+
+               CONFIG_SPL_FAT_SUPPORT
+               Support for fs/fat/libfat.o in SPL binary
+
+               CONFIG_SPL_FAT_LOAD_PAYLOAD_NAME
+               Filename to read to load U-Boot when reading from FAT
+
+               CONFIG_SPL_NAND_SIMPLE
+               Support for drivers/mtd/nand/libnand.o in SPL binary
+
+               CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT,
+               CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE,
+               CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS,
+               CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE,
+               CONFIG_SYS_NAND_ECCBYTES
+               Defines the size and behavior of the NAND that SPL uses
+               to read U-Boot with CONFIG_SPL_NAND_SIMPLE
+
+               CONFIG_SYS_NAND_U_BOOT_OFFS
+               Location in NAND for CONFIG_SPL_NAND_SIMPLE to read U-Boot
+               from.
+
+               CONFIG_SYS_NAND_U_BOOT_START
+               Location in memory for CONFIG_SPL_NAND_SIMPLE to load U-Boot
+               to.
+
+               CONFIG_SYS_NAND_HW_ECC_OOBFIRST
+               Define this if you need to first read the OOB and then the
+               data. This is used for example on davinci plattforms.
+
+               CONFIG_SPL_OMAP3_ID_NAND
+               Support for an OMAP3-specific set of functions to return the
+               ID and MFR of the first attached NAND chip, if present.
+

                CONFIG_SPL_SERIAL_SUPPORT
                Support for drivers/serial/libserial.o in SPL binary
 
                CONFIG_SPL_SERIAL_SUPPORT
                Support for drivers/serial/libserial.o in SPL binary
 


@@ -2335,9 +2597,6 @@ FIT uImage format:
                CONFIG_SPL_SPI_SUPPORT
                Support for drivers/spi/libspi.o in SPL binary
 
                CONFIG_SPL_SPI_SUPPORT
                Support for drivers/spi/libspi.o in SPL binary
 

-               CONFIG_SPL_FAT_SUPPORT
-               Support for fs/fat/libfat.o in SPL binary
-

                CONFIG_SPL_LIBGENERIC_SUPPORT
                Support for lib/libgeneric.o in SPL binary
 
                CONFIG_SPL_LIBGENERIC_SUPPORT
                Support for lib/libgeneric.o in SPL binary
 


@@ -2388,6 +2647,20 @@ Modem Support:
 
                See also: doc/README.Modem
 
 
                See also: doc/README.Modem
 

+Board initialization settings:
+------------------------------
+
+During Initialization u-boot calls a number of board specific functions
+to allow the preparation of board specific prerequisites, e.g. pin setup
+before drivers are initialized. To enable these callbacks the
+following configuration macros have to be defined. Currently this is
+architecture specific, so please check arch/your_architecture/lib/board.c
+typically in board_init_f() and board_init_r().
+
+- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f()
+- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r()
+- CONFIG_BOARD_LATE_INIT: Call board_late_init()
+- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init()

 
 Configuration Settings:
 -----------------------
 
 Configuration Settings:
 -----------------------


@@ -2505,7 +2778,7 @@ Configuration Settings:
                used) must be put below this limit, unless "bootm_low"
                enviroment variable is defined and non-zero. In such case
                all data for the Linux kernel must be between "bootm_low"
                used) must be put below this limit, unless "bootm_low"
                enviroment variable is defined and non-zero. In such case
                all data for the Linux kernel must be between "bootm_low"

-               and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.  The environment
+               and "bootm_low" + CONFIG_SYS_BOOTMAPSZ.  The environment

                variable "bootm_mapsize" will override the value of
                CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
                then the value in "bootm_size" will be used instead.
                variable "bootm_mapsize" will override the value of
                CONFIG_SYS_BOOTMAPSZ.  If CONFIG_SYS_BOOTMAPSZ is undefined,
                then the value in "bootm_size" will be used instead.


@@ -2778,6 +3051,24 @@ to save the current settings.
          environment area within the total memory of your DataFlash placed
          at the specified address.
 
          environment area within the total memory of your DataFlash placed
          at the specified address.
 

+- CONFIG_ENV_IS_IN_REMOTE:
+
+       Define this if you have a remote memory space which you
+       want to use for the local device's environment.
+
+       - CONFIG_ENV_ADDR:
+       - CONFIG_ENV_SIZE:
+
+         These two #defines specify the address and size of the
+         environment area within the remote memory space. The
+         local device can get the environment from remote memory
+         space by SRIO or other links.
+
+BE CAREFUL! For some special cases, the local device can not use
+"saveenv" command. For example, the local device will get the
+environment stored in a remote NOR flash by SRIO link, but it can
+not erase, write this NOR flash by SRIO interface.
+

 - CONFIG_ENV_IS_IN_NAND:
 
        Define this if you have a NAND device which you want to use
 - CONFIG_ENV_IS_IN_NAND:
 
        Define this if you have a NAND device which you want to use


@@ -2795,7 +3086,7 @@ to save the current settings.
          This setting describes a second storage area of CONFIG_ENV_SIZE
          size used to hold a redundant copy of the environment data, so
          that there is a valid backup copy in case there is a power failure
          This setting describes a second storage area of CONFIG_ENV_SIZE
          size used to hold a redundant copy of the environment data, so
          that there is a valid backup copy in case there is a power failure

-         during a "saveenv" operation.  CONFIG_ENV_OFFSET_RENDUND must be
+         during a "saveenv" operation.  CONFIG_ENV_OFFSET_RENDUND must be

          aligned to an erase block boundary.
 
        - CONFIG_ENV_RANGE (optional):
          aligned to an erase block boundary.
 
        - CONFIG_ENV_RANGE (optional):


@@ -2889,7 +3180,7 @@ Low Level (hardware related) configuration options:
 - CONFIG_SYS_CCSRBAR_PHYS:
                Physical address of CCSR.  CCSR can be relocated to a new
                physical address, if desired.  In this case, this macro should
 - CONFIG_SYS_CCSRBAR_PHYS:
                Physical address of CCSR.  CCSR can be relocated to a new
                physical address, if desired.  In this case, this macro should

-               be set to that address.  Otherwise, it should be set to the
+               be set to that address.  Otherwise, it should be set to the

                same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
                is typically relocated on 36-bit builds.  It is recommended
                that this macro be defined via the _HIGH and _LOW macros:
                same value as CONFIG_SYS_CCSRBAR_DEFAULT.  For example, CCSR
                is typically relocated on 36-bit builds.  It is recommended
                that this macro be defined via the _HIGH and _LOW macros:


@@ -3156,7 +3447,7 @@ Low Level (hardware related) configuration options:
                globally (CONFIG_CMD_MEM).
 
 - CONFIG_SKIP_LOWLEVEL_INIT
                globally (CONFIG_CMD_MEM).
 
 - CONFIG_SKIP_LOWLEVEL_INIT

-               [ARM, MIPS only] If this variable is defined, then certain
+               [ARM, NDS32, MIPS only] If this variable is defined, then certain

                low level initializations (like setting up the memory
                controller) are omitted and/or U-Boot does not
                relocate itself into RAM.
                low level initializations (like setting up the memory
                controller) are omitted and/or U-Boot does not
                relocate itself into RAM.


@@ -3177,6 +3468,50 @@ Low Level (hardware related) configuration options:
                be used if available. These functions may be faster under some
                conditions but may increase the binary size.
 
                be used if available. These functions may be faster under some
                conditions but may increase the binary size.
 

+Freescale QE/FMAN Firmware Support:
+-----------------------------------
+
+The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the
+loading of "firmware", which is encoded in the QE firmware binary format.
+This firmware often needs to be loaded during U-Boot booting, so macros
+are used to identify the storage device (NOR flash, SPI, etc) and the address
+within that device.
+
+- CONFIG_SYS_QE_FMAN_FW_ADDR
+       The address in the storage device where the firmware is located.  The
+       meaning of this address depends on which CONFIG_SYS_QE_FW_IN_xxx macro
+       is also specified.
+
+- CONFIG_SYS_QE_FMAN_FW_LENGTH
+       The maximum possible size of the firmware.  The firmware binary format
+       has a field that specifies the actual size of the firmware, but it
+       might not be possible to read any part of the firmware unless some
+       local storage is allocated to hold the entire firmware first.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_NOR
+       Specifies that QE/FMAN firmware is located in NOR flash, mapped as
+       normal addressable memory via the LBC.  CONFIG_SYS_FMAN_FW_ADDR is the
+       virtual address in NOR flash.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_NAND
+       Specifies that QE/FMAN firmware is located in NAND flash.
+       CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_MMC
+       Specifies that QE/FMAN firmware is located on the primary SD/MMC
+       device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_SPIFLASH
+       Specifies that QE/FMAN firmware is located on the primary SPI
+       device.  CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device.
+
+- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE
+       Specifies that QE/FMAN firmware is located in the remote (master)
+       memory space.   CONFIG_SYS_FMAN_FW_ADDR is a virtual address which
+       can be mapped from slave TLB->slave LAW->slave SRIO outbound window
+       ->master inbound window->master LAW->the ucode address in master's
+       NOR flash.
+

 Building the Software:
 ======================
 
 Building the Software:
 ======================
 


@@ -3213,7 +3548,7 @@ is done by typing:
        make NAME_config
 
 where "NAME_config" is the name of one of the existing configu-
        make NAME_config
 
 where "NAME_config" is the name of one of the existing configu-

-rations; see the main Makefile for supported names.
+rations; see boards.cfg for supported names.

 
 Note: for some board special configuration names may exist; check if
       additional information is available from the board vendor; for
 
 Note: for some board special configuration names may exist; check if
       additional information is available from the board vendor; for


@@ -3268,10 +3603,8 @@ to port U-Boot to your hardware platform. To do this, follow these
 steps:
 
 1.  Add a new configuration option for your board to the toplevel
 steps:
 
 1.  Add a new configuration option for your board to the toplevel

-    "Makefile" and to the "MAKEALL" script, using the existing
-    entries as examples. Note that here and at many other places
-    boards and other names are listed in alphabetical sort order. Please
-    keep this order.
+    "boards.cfg" file, using the existing entries as examples.
+    Follow the instructions there to keep the boards in order.

 2.  Create a new directory to hold your board specific code. Add any
     files you need. In your board directory, you will need at least
     the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".
 2.  Create a new directory to hold your board specific code. Add any
     files you need. In your board directory, you will need at least
     the "Makefile", a "<board>.c", "flash.c" and "u-boot.lds".


@@ -3337,9 +3670,11 @@ go       - start application at address 'addr'
 run    - run commands in an environment variable
 bootm  - boot application image from memory
 bootp  - boot image via network using BootP/TFTP protocol
 run    - run commands in an environment variable
 bootm  - boot application image from memory
 bootp  - boot image via network using BootP/TFTP protocol

+bootz   - boot zImage from memory

 tftpboot- boot image via network using TFTP protocol
               and env variables "ipaddr" and "serverip"
               (and eventually "gatewayip")
 tftpboot- boot image via network using TFTP protocol
               and env variables "ipaddr" and "serverip"
               (and eventually "gatewayip")

+tftpput - upload a file via network using TFTP protocol

 rarpboot- boot image via network using RARP/TFTP protocol
 diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
 loads  - load S-Record file over serial line
 rarpboot- boot image via network using RARP/TFTP protocol
 diskboot- boot from IDE devicebootd   - boot default, i.e., run 'bootcmd'
 loads  - load S-Record file over serial line


@@ -3420,7 +3755,7 @@ List of environment variables (most likely not complete):
                  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
                  bootm_mapsize.
 
                  kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and
                  bootm_mapsize.
 

-  bootm_mapsize        - Size of the initial memory mapping for the Linux kernel.
+  bootm_mapsize - Size of the initial memory mapping for the Linux kernel.

                  This variable is given as a hexadecimal number and it
                  defines the size of the memory region starting at base
                  address bootm_low that is accessible by the Linux kernel
                  This variable is given as a hexadecimal number and it
                  defines the size of the memory region starting at base
                  address bootm_low that is accessible by the Linux kernel


@@ -3456,6 +3791,14 @@ List of environment variables (most likely not complete):
 
   fdt_high     - if set this restricts the maximum address that the
                  flattened device tree will be copied into upon boot.
 
   fdt_high     - if set this restricts the maximum address that the
                  flattened device tree will be copied into upon boot.

+                 For example, if you have a system with 1 GB memory
+                 at physical address 0x10000000, while Linux kernel
+                 only recognizes the first 704 MB as low memory, you
+                 may need to set fdt_high as 0x3C000000 to have the
+                 device tree blob be copied to the maximum address
+                 of the 704 MB low memory, so that Linux kernel can
+                 access it during the boot procedure.
+

                  If this is set to the special value 0xFFFFFFFF then
                  the fdt will not be copied at all on boot.  For this
                  to work it must reside in writable memory, have
                  If this is set to the special value 0xFFFFFFFF then
                  the fdt will not be copied at all on boot.  For this
                  to work it must reside in writable memory, have


@@ -3463,6 +3806,10 @@ List of environment variables (most likely not complete):
                  add the information it needs into it, and the memory
                  must be accessible by the kernel.
 
                  add the information it needs into it, and the memory
                  must be accessible by the kernel.
 

+  fdtcontroladdr- if set this is the address of the control flattened
+                 device tree used by U-Boot when CONFIG_OF_CONTROL is
+                 defined.
+

   i2cfast      - (PPC405GP|PPC405EP only)
                  if set to 'y' configures Linux I2C driver for fast
                  mode (400kHZ). This environment variable is used in
   i2cfast      - (PPC405GP|PPC405EP only)
                  if set to 'y' configures Linux I2C driver for fast
                  mode (400kHZ). This environment variable is used in


@@ -3558,6 +3905,25 @@ List of environment variables (most likely not complete):
                  Ethernet is encapsulated/received over 802.1q
                  VLAN tagged frames.
 
                  Ethernet is encapsulated/received over 802.1q
                  VLAN tagged frames.
 

+The following image location variables contain the location of images
+used in booting. The "Image" column gives the role of the image and is
+not an environment variable name. The other columns are environment
+variable names. "File Name" gives the name of the file on a TFTP
+server, "RAM Address" gives the location in RAM the image will be
+loaded to, and "Flash Location" gives the image's address in NOR
+flash or offset in NAND flash.
+
+*Note* - these variables don't have to be defined for all boards, some
+boards currenlty use other variables for these purposes, and some
+boards use these variables for other purposes.
+
+Image              File Name        RAM Address       Flash Location
+-----              ---------        -----------       --------------
+u-boot             u-boot           u-boot_addr_r     u-boot_addr
+Linux kernel       bootfile         kernel_addr_r     kernel_addr
+device tree blob    fdtfile         fdt_addr_r        fdt_addr
+ramdisk                    ramdiskfile      ramdisk_addr_r    ramdisk_addr
+

 The following environment variables may be used and automatically
 updated by the network boot commands ("bootp" and "rarpboot"),
 depending the information provided by your boot server:
 The following environment variables may be used and automatically
 updated by the network boot commands ("bootp" and "rarpboot"),
 depending the information provided by your boot server:


@@ -3671,7 +4037,7 @@ o If neither SROM nor the environment contain a MAC address, an error
   is raised.
 
 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses
   is raised.
 
 If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses

-will be programmed into hardware as part of the initialization process.  This
+will be programmed into hardware as part of the initialization process.         This

 may be skipped by setting the appropriate 'ethmacskip' environment variable.
 The naming convention is as follows:
 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.
 may be skipped by setting the appropriate 'ethmacskip' environment variable.
 The naming convention is as follows:
 "ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc.


@@ -3704,8 +4070,8 @@ details; basically, the header defines the following image properties:
   Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
   INTEGRITY).
 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,
   Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS,
   INTEGRITY).
 * Target CPU Architecture (Provisions for Alpha, ARM, AVR32, Intel x86,

-  IA64, MIPS, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
-  Currently supported: ARM, AVR32, Intel x86, MIPS, Nios II, PowerPC).
+  IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit;
+  Currently supported: ARM, AVR32, Intel x86, MIPS, NDS32, Nios II, PowerPC).

 * Compression Type (uncompressed, gzip, bzip2)
 * Load Address
 * Entry Point
 * Compression Type (uncompressed, gzip, bzip2)
 * Load Address
 * Entry Point


@@ -4125,6 +4491,18 @@ U-Boot supports the following image types:
        useful when you configure U-Boot to use a real shell (hush)
        as command interpreter.
 
        useful when you configure U-Boot to use a real shell (hush)
        as command interpreter.
 

+Booting the Linux zImage:
+-------------------------
+
+On some platforms, it's possible to boot Linux zImage. This is done
+using the "bootz" command. The syntax of "bootz" command is the same
+as the syntax of "bootm" command.
+
+Note, defining the CONFIG_SUPPORT_INITRD_RAW allows user to supply
+kernel with raw initrd images. The syntax is slightly different, the
+address of the initrd must be augmented by it's size, in the following
+format: "<initrd addres>:<initrd size>".
+

 
 Standalone HOWTO:
 =================
 
 Standalone HOWTO:
 =================


@@ -4398,6 +4776,20 @@ On Nios II, the ABI is documented here:
     Note: on Nios II, we give "-G0" option to gcc and don't use gp
     to access small data sections, so gp is free.
 
     Note: on Nios II, we give "-G0" option to gcc and don't use gp
     to access small data sections, so gp is free.
 

+On NDS32, the following registers are used:
+
+       R0-R1:  argument/return
+       R2-R5:  argument
+       R15:    temporary register for assembler
+       R16:    trampoline register
+       R28:    frame pointer (FP)
+       R29:    global pointer (GP)
+       R30:    link register (LP)
+       R31:    stack pointer (SP)
+       PC:     program counter (PC)
+
+    ==> U-Boot will use R10 to hold a pointer to the global data
+

 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
 or current versions of GCC may "optimize" the code too much.
 
 NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope,
 or current versions of GCC may "optimize" the code too much.