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Diffstat (limited to 'Documentation/frv/booting.txt')
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diff --git a/Documentation/frv/booting.txt b/Documentation/frv/booting.txt new file mode 100644 index 000000000000..ace200b7c214 --- /dev/null +++ b/Documentation/frv/booting.txt @@ -0,0 +1,181 @@ + ========================= + BOOTING FR-V LINUX KERNEL + ========================= + +====================== +PROVIDING A FILESYSTEM +====================== + +First of all, a root filesystem must be made available. This can be done in +one of two ways: + + (1) NFS Export + + A filesystem should be constructed in a directory on an NFS server that + the target board can reach. This directory should then be NFS exported + such that the target board can read and write into it as root. + + (2) Flash Filesystem (JFFS2 Recommended) + + In this case, the image must be stored or built up on flash before it + can be used. A complete image can be built using the mkfs.jffs2 or + similar program and then downloaded and stored into flash by RedBoot. + + +======================== +LOADING THE KERNEL IMAGE +======================== + +The kernel will need to be loaded into RAM by RedBoot (or by some alternative +boot loader) before it can be run. The kernel image (arch/frv/boot/Image) may +be loaded in one of three ways: + + (1) Load from Flash + + This is the simplest. RedBoot can store an image in the flash (see the + RedBoot documentation) and then load it back into RAM. RedBoot keeps + track of the load address, entry point and size, so the command to do + this is simply: + + fis load linux + + The image is then ready to be executed. + + (2) Load by TFTP + + The following command will download a raw binary kernel image from the + default server (as negotiated by BOOTP) and store it into RAM: + + load -b 0x00100000 -r /tftpboot/image.bin + + The image is then ready to be executed. + + (3) Load by Y-Modem + + The following command will download a raw binary kernel image across the + serial port that RedBoot is currently using: + + load -m ymodem -b 0x00100000 -r zImage + + The serial client (such as minicom) must then be told to transmit the + program by Y-Modem. + + When finished, the image will then be ready to be executed. + + +================== +BOOTING THE KERNEL +================== + +Boot the image with the following RedBoot command: + + exec -c "<CMDLINE>" 0x00100000 + +For example: + + exec -c "console=ttySM0,115200 ip=:::::dhcp root=/dev/mtdblock2 rw" + +This will start the kernel running. Note that if the GDB-stub is compiled in, +then the kernel will immediately wait for GDB to connect over serial before +doing anything else. See the section on kernel debugging with GDB. + +The kernel command line <CMDLINE> tells the kernel where its console is and +how to find its root filesystem. This is made up of the following components, +separated by spaces: + + (*) console=ttyS<x>[,<baud>[<parity>[<bits>[<flow>]]]] + + This specifies that the system console should output through on-chip + serial port <x> (which can be "0" or "1"). + + <baud> is a standard baud rate between 1200 and 115200 (default 9600). + + <parity> is a parity setting of "N", "O", "E", "M" or "S" for None, Odd, + Even, Mark or Space. "None" is the default. + + <stop> is "7" or "8" for the number of bits per character. "8" is the + default. + + <flow> is "r" to use flow control (XCTS on serial port 2 only). The + default is to not use flow control. + + For example: + + console=ttyS0,115200 + + To use the first on-chip serial port at baud rate 115200, no parity, 8 + bits, and no flow control. + + (*) root=/dev/<xxxx> + + This specifies the device upon which the root filesystem resides. For + example: + + /dev/nfs NFS root filesystem + /dev/mtdblock3 Fourth RedBoot partition on the System Flash + + (*) rw + + Start with the root filesystem mounted Read/Write. + + The remaining components are all optional: + + (*) ip=<ip>::::<host>:<iface>:<cfg> + + Configure the network interface. If <cfg> is "off" then <ip> should + specify the IP address for the network device <iface>. <host> provide + the hostname for the device. + + If <cfg> is "bootp" or "dhcp", then all of these parameters will be + discovered by consulting a BOOTP or DHCP server. + + For example, the following might be used: + + ip=192.168.73.12::::frv:eth0:off + + This sets the IP address on the VDK motherboard RTL8029 ethernet chipset + (eth0) to be 192.168.73.12, and sets the board's hostname to be "frv". + + (*) nfsroot=<server>:<dir>[,v<vers>] + + This is mandatory if "root=/dev/nfs" is given as an option. It tells the + kernel the IP address of the NFS server providing its root filesystem, + and the pathname on that server of the filesystem. + + The NFS version to use can also be specified. v2 and v3 are supported by + Linux. + + For example: + + nfsroot=192.168.73.1:/nfsroot-frv + + (*) profile=1 + + Turns on the kernel profiler (accessible through /proc/profile). + + (*) console=gdb0 + + This can be used as an alternative to the "console=ttyS..." listed + above. I tells the kernel to pass the console output to GDB if the + gdbstub is compiled in to the kernel. + + If this is used, then the gdbstub passes the text to GDB, which then + simply dumps it to its standard output. + + (*) mem=<xxx>M + + Normally the kernel will work out how much SDRAM it has by reading the + SDRAM controller registers. That can be overridden with this + option. This allows the kernel to be told that it has <xxx> megabytes of + memory available. + + (*) init=<prog> [<arg> [<arg> [<arg> ...]]] + + This tells the kernel what program to run initially. By default this is + /sbin/init, but /sbin/sash or /bin/sh are common alternatives. + + (*) vdc=... + + This option configures the MB93493 companion chip visual display + driver. Please see Documentation/frv/mb93493/vdc.txt for more + information. |