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