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Diffstat (limited to 'docs/firmware/fw_payload.md')
| -rw-r--r-- | docs/firmware/fw_payload.md | 31 |
1 files changed, 15 insertions, 16 deletions
diff --git a/docs/firmware/fw_payload.md b/docs/firmware/fw_payload.md index 72ea9bb..c9a9ad8 100644 --- a/docs/firmware/fw_payload.md +++ b/docs/firmware/fw_payload.md @@ -2,22 +2,22 @@ OpenSBI Firmware with Payload *FW_PAYLOAD* ========================================== OpenSBI **firmware with Payload (FW_PAYLOAD)** is a firmware which directly -includes the binary for the booting stage to follow OpenSBI firmware execution. -Typically, this payload will be a bootloader or an OS kernel. +includes the binary for the booting stage to follow the OpenSBI firmware +execution. Typically, this payload will be a bootloader or an OS kernel. A *FW_PAYLOAD* firmware is particularly useful when the booting stage executed -prior to OpenSBI firmware is not capable of loading both OpenSBI firmware and -the booting stage to follow OpenSBI firmware. +prior to the OpenSBI firmware is not capable of loading both the OpenSBI +firmware and the booting stage to follow OpenSBI firmware. A *FW_PAYLOAD* firmware is also useful for cases where the booting stage prior -to OpenSBI firmware does not pass a *flattened device tree (FDT file)*. In such -case, a *FW_PAYLOAD* firmware allows embedding a flattened device tree in the -.text section of the final firmware. +to the OpenSBI firmware does not pass a *flattened device tree (FDT file)*. In +such a case, a *FW_PAYLOAD* firmware allows embedding a flattened device tree +in the .text section of the final firmware. Enabling *FW_PAYLOAD* compilation --------------------------------- -The *FW_PAYLOAD* firmware can be enabled by any of the following methods. +The *FW_PAYLOAD* firmware can be enabled by any of the following methods: 1. Specifying `FW_PAYLOAD=y` on the top level `make` command line. 2. Specifying `FW_PAYLOAD=y` in the target platform *config.mk* configuration @@ -25,7 +25,7 @@ The *FW_PAYLOAD* firmware can be enabled by any of the following methods. The compiled *FW_PAYLOAD* firmware ELF file is named *fw_jump.elf*. Its expanded image file is *fw_payload.bin*. Both files are created in the -platform specific build directory under the +platform-specific build directory under the *build/platform/<platform_subdir>/firmware* directory. Configuration Options @@ -34,7 +34,7 @@ Configuration Options A *FW_PAYLOAD* firmware is built according to configuration parameters and options. These configuration parameters can be defined using either the top level `make` command line or the target platform *config.mk* configuration -file. The parameters currently defined are as follows. +file. The parameters currently defined are as follows: * **FW_PAYLOAD_OFFSET** - Offset from *FW_TEXT_BASE* where the payload binary will be linked in the final *FW_PAYLOAD* firmware binary image. This @@ -47,8 +47,8 @@ file. The parameters currently defined are as follows. will be linked after the end of the base firmware binary in the final *FW_PAYLOAD* firmware binary image. This configuration parameter is mandatory if *FW_PAYLOAD_OFFSET* is not defined. If both *FW_PAYLOAD_OFFSET* and - *FW_PAYLOAD_ALIGN* are defined, *FW_PAYLOAD_OFFSET* is used and - *FW_PAYLOAD_ALIGN* ignored. + *FW_PAYLOAD_ALIGN* are defined, *FW_PAYLOAD_OFFSET* is used and + *FW_PAYLOAD_ALIGN* is ignored. * **FW_PAYLOAD_PATH** - Path to the image file of the next booting stage binary. If this option is not provided then a simple test payload is @@ -78,13 +78,12 @@ file. The parameters currently defined are as follows. *FW_PAYLOAD* Example -------------------- -The *[qemu/virt]* and *[qemu/sifive_u]* platforms illustrates how to configure +The *[qemu/virt]* and *[qemu/sifive_u]* platforms illustrate how to configure and use a *FW_PAYLOAD* firmware. Detailed information regarding these platforms -can be found in the platforms documentation files. +can be found in the platform documentation files. -The *kendryte/k210* platform also enables build of a *FW_PAYLOAD* using an +The *kendryte/k210* platform also enables a build of a *FW_PAYLOAD* using an internally defined device tree file (*FW_PAYLOAD_FDT*). [qemu/virt]: ../platform/qemu_virt.md [qemu/sifive_u]: ../platform/qemu_sifive_u.md - |