Alistair Francis <alistair.fran...@xilinx.com> writes: > Signed-off-by: Alistair Francis <alistair.fran...@xilinx.com> > Reviewed-by: Peter Maydell <peter.mayd...@linaro.org> > --- > V11: > - Fix corrections > V10: > - Split the data loading and PC setting > V9: > - Clarify the image loading options > V8: > - Improve documentation > V6: > - Fixup documentation > V4: > - Re-write to be more comprehensive > > docs/generic-loader.txt | 81 > +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 81 insertions(+) > create mode 100644 docs/generic-loader.txt > > diff --git a/docs/generic-loader.txt b/docs/generic-loader.txt > new file mode 100644 > index 0000000..d1f8ce3 > --- /dev/null > +++ b/docs/generic-loader.txt > @@ -0,0 +1,81 @@ > +Copyright (c) 2016 Xilinx Inc. > + > +This work is licensed under the terms of the GNU GPL, version 2 or later. > See > +the COPYING file in the top-level directory. > + > + > +The 'loader' device allows the user to load multiple images or values into > +QEMU at startup. > + > +Loading Data into Memory Values > +--------------------- > +The loader device allows memory values to be set from the command line. This > +can be done by following the syntax below: > + > + -device loader,addr=<addr>,data=<data>,data-len=<data-len> > + [,data-be=<data-be>][,cpu-num=<cpu-num>] > + > + <addr> - The address to store the data in. > + <data> - The value to be written to the address. The maximum size of > + the data is 8 bytes. > + <data-len> - The length of the data in bytes. This argument must be > + included if the data argument is. > + <data-be> - Set to true if the data to be stored on the guest should be > + written as big endian data. The default is to write little > + endian data. > + <cpu-num> - The number of the CPU's address space where the data should > + be loaded. If not specified the address space of the first > + CPU is used. > + > +For all values both hex and decimal values are allowed. By default the values > +will be parsed as decimal. To use hex values the user should prefix the > number > +with a '0x'.
Unless you bypassed QemuOpts number parsing somehow, octal works as well. In case you did bypass: don't! Command line consistency matters. Follow-up patch reverting the bypass would be required. Not sure we want to document QemuOpts number syntax everywhere we explain how a certain feature uses the command line. A pointer to the canonical place could be better. Anyway, not something that needs fixing before we commit. > + > +An example of loading value 0x8000000e to address 0xfd1a0104 is: > + -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4 > + > +Setting a CPU's Program Counter > +--------------------- > +The loader device allows the CPU's PC to be set from the command line. This > +can be done by following the syntax below: > + > + -device loader,addr=<addr>,cpu-num=<cpu-num> > + > + <addr> - The value to use as the CPU's PC. > + <cpu-num> - The number of the CPU whose PC should be set to the > + specified value. > + > +For all values both hex and decimal values are allowed. By default the values > +will be parsed as decimal. To use hex values the user should prefix the > number > +with a '0x'. > + > +An example of setting CPU 0's PC to 0x8000 is: > + -device loader,addr=0x8000,cpu-num=0 > + > +Loading Files > +--------------------- > +The loader device also allows files to be loaded into memory. This can be > done > +similarly to setting memory values. The syntax is shown below: > + > + -device > loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>] > + > + <file> - A file to be loaded into memory > + <addr> - The addr in memory that the file should be loaded. This is > + ignored if you are using an ELF (unless force-raw is true). > + This is required if you aren't loading an ELF. > + <cpu-num> - This specifies the CPU that should be used. This is an > + optional argument and will cause the CPU's PC to be set to > + where the image is stored or in the case of an ELF file to > + the value in the header. This option should only be used > + for the boot image. > + This will also cause the image to be written to the > specified > + CPU's address space. If not specified, the default is CPU > 0. Using @cpu-num both for further specifying the meaning of @addr and for setting that CPU's PC is awkward. Are you sure there will never be a use case where you need to specify the CPU without also setting its PC? To be clear: while I feel this is a question we must discuss and resolve, I don't think we need to hold the series for it. > + <force-raw> - Forces the file to be treated as a raw image. This can be > + used to specify the load address of ELF files. "Specifying the load address of an ELF file" sounds like loading a position-independent ELF file at a particular address. But I guess this is actually for loading a file raw even though it is recognized by QEMU as ELF. > + > +For all values both hex and decimal values are allowed. By default the values > +will be parsed as decimal. To use hex values the user should prefix the > number > +with a '0x'. > + > +An example of loading an ELF file which CPU0 will boot is shown below: > + -device loader,file=./images/boot.elf,cpu-num=0 Naive question: if you want to more than one thing (where "thing" is one of the three cases described above), do you need a separate -device for each, or can you combine them into one? Again, while my questions may lead to improvements, they can be applied on top.
