| ppce500 generic platform (``ppce500``) |
| ====================================== |
| |
| QEMU for PPC supports a special ``ppce500`` machine designed for emulation and |
| virtualization purposes. |
| |
| Supported devices |
| ----------------- |
| |
| The ``ppce500`` machine supports the following devices: |
| |
| * PowerPC e500 series core (e500v2/e500mc/e5500/e6500) |
| * Configuration, Control, and Status Register (CCSR) |
| * Multicore Programmable Interrupt Controller (MPIC) with MSI support |
| * 1 16550A UART device |
| * 1 Freescale MPC8xxx I2C controller |
| * 1 Pericom pt7c4338 RTC via I2C |
| * 1 Freescale MPC8xxx GPIO controller |
| * Power-off functionality via one GPIO pin |
| * 1 Freescale MPC8xxx PCI host controller |
| * VirtIO devices via PCI bus |
| * 1 Freescale Enhanced Secure Digital Host controller (eSDHC) |
| * 1 Freescale Enhanced Triple Speed Ethernet controller (eTSEC) |
| |
| Hardware configuration information |
| ---------------------------------- |
| |
| The ``ppce500`` machine automatically generates a device tree blob ("dtb") |
| which it passes to the guest, if there is no ``-dtb`` option. This provides |
| information about the addresses, interrupt lines and other configuration of |
| the various devices in the system. |
| |
| If users want to provide their own DTB, they can use the ``-dtb`` option. |
| These DTBs should have the following requirements: |
| |
| * The number of subnodes under /cpus node should match QEMU's ``-smp`` option |
| * The /memory reg size should match QEMU’s selected ram_size via ``-m`` |
| |
| Both ``qemu-system-ppc`` and ``qemu-system-ppc64`` provide emulation for the |
| following 32-bit PowerPC CPUs: |
| |
| * e500v2 |
| * e500mc |
| |
| Additionally ``qemu-system-ppc64`` provides support for the following 64-bit |
| PowerPC CPUs: |
| |
| * e5500 |
| * e6500 |
| |
| The CPU type can be specified via the ``-cpu`` command line. If not specified, |
| it creates a machine with e500v2 core. The following example shows an e6500 |
| based machine creation: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -nographic -M ppce500 -cpu e6500 |
| |
| Boot options |
| ------------ |
| |
| The ``ppce500`` machine can start using the standard -kernel functionality |
| for loading a payload like an OS kernel (e.g.: Linux), or U-Boot firmware. |
| |
| When -bios is omitted, the default pc-bios/u-boot.e500 firmware image is used |
| as the BIOS. QEMU follows below truth table to select which payload to execute: |
| |
| ===== ========== ======= |
| -bios -kernel payload |
| ===== ========== ======= |
| N N u-boot |
| N Y kernel |
| Y don't care u-boot |
| ===== ========== ======= |
| |
| When both -bios and -kernel are present, QEMU loads U-Boot and U-Boot in turns |
| automatically loads the kernel image specified by the -kernel parameter via |
| U-Boot's built-in "bootm" command, hence a legacy uImage format is required in |
| such scenario. |
| |
| Running Linux kernel |
| -------------------- |
| |
| Linux mainline v5.11 release is tested at the time of writing. To build a |
| Linux mainline kernel that can be booted by the ``ppce500`` machine in |
| 64-bit mode, simply configure the kernel using the defconfig configuration: |
| |
| .. code-block:: bash |
| |
| $ export ARCH=powerpc |
| $ export CROSS_COMPILE=powerpc-linux- |
| $ make corenet64_smp_defconfig |
| $ make menuconfig |
| |
| then manually select the following configuration: |
| |
| Platform support > Freescale Book-E Machine Type > QEMU generic e500 platform |
| |
| To boot the newly built Linux kernel in QEMU with the ``ppce500`` machine: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -M ppce500 -cpu e5500 -smp 4 -m 2G \ |
| -display none -serial stdio \ |
| -kernel vmlinux \ |
| -initrd /path/to/rootfs.cpio \ |
| -append "root=/dev/ram" |
| |
| To build a Linux mainline kernel that can be booted by the ``ppce500`` machine |
| in 32-bit mode, use the same 64-bit configuration steps except the defconfig |
| file should use corenet32_smp_defconfig. |
| |
| To boot the 32-bit Linux kernel: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -M ppce500 -cpu e500mc -smp 4 -m 2G \ |
| -display none -serial stdio \ |
| -kernel vmlinux \ |
| -initrd /path/to/rootfs.cpio \ |
| -append "root=/dev/ram" |
| |
| Running U-Boot |
| -------------- |
| |
| U-Boot mainline v2021.07 release is tested at the time of writing. To build a |
| U-Boot mainline bootloader that can be booted by the ``ppce500`` machine, use |
| the qemu-ppce500_defconfig with similar commands as described above for Linux: |
| |
| .. code-block:: bash |
| |
| $ export CROSS_COMPILE=powerpc-linux- |
| $ make qemu-ppce500_defconfig |
| |
| You will get u-boot file in the build tree. |
| |
| When U-Boot boots, you will notice the following if using with ``-cpu e6500``: |
| |
| .. code-block:: none |
| |
| CPU: Unknown, Version: 0.0, (0x00000000) |
| Core: e6500, Version: 2.0, (0x80400020) |
| |
| This is because we only specified a core name to QEMU and it does not have a |
| meaningful SVR value which represents an actual SoC that integrates such core. |
| You can specify a real world SoC device that QEMU has built-in support but all |
| these SoCs are e500v2 based MPC85xx series, hence you cannot test anything |
| built for P4080 (e500mc), P5020 (e5500) and T2080 (e6500). |
| |
| Networking |
| ---------- |
| |
| By default a VirtIO standard PCI networking device is connected as an ethernet |
| interface at PCI address 0.1.0, but we can switch that to an e1000 NIC by: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -M ppce500 -smp 4 -m 2G \ |
| -display none -serial stdio \ |
| -bios u-boot \ |
| -nic tap,ifname=tap0,script=no,downscript=no,model=e1000 |
| |
| The QEMU ``ppce500`` machine can also dynamically instantiate an eTSEC device |
| if “-device eTSEC” is given to QEMU: |
| |
| .. code-block:: bash |
| |
| -netdev tap,ifname=tap0,script=no,downscript=no,id=net0 -device eTSEC,netdev=net0 |
| |
| Root file system on flash drive |
| ------------------------------- |
| |
| Rather than using a root file system on ram disk, it is possible to have it on |
| CFI flash. Given an ext2 image whose size must be a power of two, it can be used |
| as follows: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -M ppce500 -cpu e500mc -smp 4 -m 2G \ |
| -display none -serial stdio \ |
| -kernel vmlinux \ |
| -drive if=pflash,file=/path/to/rootfs.ext2,format=raw \ |
| -append "rootwait root=/dev/mtdblock0" |
| |
| Alternatively, the root file system can also reside on an emulated SD card |
| whose size must again be a power of two: |
| |
| .. code-block:: bash |
| |
| $ qemu-system-ppc64 -M ppce500 -cpu e500mc -smp 4 -m 2G \ |
| -display none -serial stdio \ |
| -kernel vmlinux \ |
| -device sd-card,drive=mydrive \ |
| -drive id=mydrive,if=none,file=/path/to/rootfs.ext2,format=raw \ |
| -append "rootwait root=/dev/mmcblk0" |