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diff --git a/docs/system/ppc/ppce500.rst b/docs/system/ppc/ppce500.rst new file mode 100644 index 0000000000..7a815c1881 --- /dev/null +++ b/docs/system/ppc/ppce500.rst @@ -0,0 +1,156 @@ +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 + +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 senario. + +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-ppc{64|32} -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 v2021.04 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). + +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-ppc -M ppce500 -smp 4 -m 2G \ + -display none -serial stdio \ + -bios u-boot \ + -nic tap,ifname=tap0,script=no,downscript=no,model=e1000 |