The J7200 processors have Cortex-R5F subsystems in addition to a dual core Cortex-A72 subsystem. Please refer to the J7200 Technical Reference Manual for details.
This article is geared toward J7200 users that are running Linux on the Cortex A72 cores. The goal is to help users understand how to establish IPC communication with R5F cores.
There are many facets to this task: building, loading, debugging, memory sharing, etc. This article intends to take incremental steps toward understanding all of those pieces.
J7200 SOC's have multiple processor cores - Cortex-A72, Cortex-R5F cores.
The MCU R5F firmware runs device manager software (SciServer). The MCU R5F firmware (DM) is integrated as part of tispl.bin binary and is started early in the boot process, right after DDR initialization, by u-boot SPL running on MCU R5.
The A72 typically runs a HLOS like Linux/Android. The R5F remote cores run No-OS or RTOS (FreeRTOS etc). In normal operation, the boot loader (U-Boot/SPL) boots and loads the A72 with the HLOS. The A72 then boots the R5F cores.
The figure below illustrates how the Remoteproc/RPMsg driver from the ARM Linux kernel communicates with the IPC driver on a remote processors (e.g. R5F) running RTOS.
In order to setup IPC on remote cores, we provide some pre-built examples in the SDK package that can be run from ARM Linux.
The remoteproc driver is hard-coded to look for specific files when loading the R5F cores. Here are the files it looks for on an J7200 device:
+------------------+-----------------+----------------------+-----------------------+
| Core Name | RemoteProc Name | Description | Firmware File Name |
+==================+=================+======================+=======================+
| R5F | 41000000.r5f | R5F core(MCU domain) | j7200-mcu-r5f0_0-fw |
+------------------+-----------------+----------------------+-----------------------+
| R5F | 41400000.r5f | R5F core(MCU domain) | j7200-mcu-r5f0_1-fw |
+------------------+-----------------+----------------------+-----------------------+
| R5F | 5c00000.r5f | R5F core(MAIN domain)| j7200-main-r5f0_0-fw |
+------------------+-----------------+----------------------+-----------------------+
| R5F | 5d00000.r5f | R5F core(MAIN domain)| j7200-main-r5f0_1-fw |
+------------------+-----------------+----------------------+-----------------------+
Generally on a target file system the above files are soft linked to the intended executable FW files:
root@j7200-evm:~# ls -l /lib/firmware/
lrwxrwxrwx 1 root root 65 Mar 9 2018 j7200-main-r5f0_0-fw -> /lib/firmware/ti-eth/j7200/app_remoteswitchcfg_server_strip.xer5f
lrwxrwxrwx 1 root root 72 Mar 9 2018 j7200-main-r5f0_0-fw-sec -> /lib/firmware/ti-eth/j7200/app_remoteswitchcfg_server_strip.xer5f.signed
lrwxrwxrwx 1 root root 67 Mar 9 2018 j7200-main-r5f0_1-fw -> /lib/firmware/ti-ipc/j7200/ipc_echo_test_mcu2_1_release_strip.xer5f
lrwxrwxrwx 1 root root 74 Mar 9 2018 j7200-main-r5f0_1-fw-sec -> /lib/firmware/ti-ipc/j7200/ipc_echo_test_mcu2_1_release_strip.xer5f.signed
lrwxrwxrwx 1 root root 67 Mar 9 2018 j7200-mcu-r5f0_0-fw -> /lib/firmware/ti-ipc/j7200/ipc_echo_testb_mcu1_0_release_strip.xer5f
lrwxrwxrwx 1 root root 67 Mar 9 2018 j7200-mcu-r5f0_1-fw -> /lib/firmware/ti-ipc/j7200/ipc_echo_test_mcu1_1_release_strip.xer5fFor updating MCU (DM) R5F firmware binary, tispl.bin needs to be recompiled with the new firmware binary as mentioned below :
Go to linux installer and replace the existing R5F MCU (DM) firmware binary with the new one
host# cp <path_to_new_fw_binary>/ipc_echo_testb_freertos_mcu1_0_release.xer5f <path_to_linux_installer>/board-support/prebuilt-images/ti-dm/j7200/ipc_echo_testb_mcu1_0_release_strip.xer5fRecompile u-boot to regenerate tispl.bin using the top level makefile.
host# make u-bootPlease refer to :ref:`top-level-makefile` for more details on Top Level makefile.
Replace the updated tispl.bin containing new R5F firmware binary in the boot partition of sdcard and reboot
host# sudo cp board-support/u-boot_build/A72/tispl.bin /media/$USER/boot
To reload a remote core with new executables, please follow the below steps.
First, identify the remotproc node associated with the remote core:
root@j7200-evm:~# head /sys/class/remoteproc/remoteproc*/name
==> /sys/class/remoteproc/remoteproc0/name <==
41000000.r5f
==> /sys/class/remoteproc/remoteproc1/name <==
5c00000.r5f
==> /sys/class/remoteproc/remoteproc2/name <==
5d00000.r5fThen, use the sysfs interface to stop the remote core. For example, to stop the Main R5FSS0
root@j7200-evm:~# echo stop > /sys/class/remoteproc/remoteproc1/state
[ 71.804687] remoteproc remoteproc1: stopped remote processor 5c00000.r5fIf needed, update the firmware symbolic link to point to a new firmware:
root@j7200-evm:/lib/firmware# ln -sf /lib/firmware/ti-ipc/j7200/ipc_echo_test_mcu2_1_release_strip.xer5f j7200-main-r5f0_1-fwFinally, use the sysfs interface to start the remote core:
root@j7200-evm:~# echo start > /sys/class/remoteproc/remoteproc1/state
[ 110.922899] remoteproc remoteproc1: powering up 5c00000.r5f
[ 110.929565] remoteproc remoteproc1: Booting fw image j7200-main-r5f0_0-fw, size 675124
[ 110.942347] rproc-virtio rproc-virtio.11.auto: assigned reserved memory node r5f-dma-memory@a2000000
[ 110.952633] virtio_rpmsg_bus virtio1: rpmsg host is online
[ 110.959449] rproc-virtio rproc-virtio.11.auto: registered virtio1 (type 7)
[ 110.966439] remoteproc remoteproc1: remote processor 5c00000.r5f is now upNote
The above process is for the gracful remote core shutdown and start. In some cases, graceful shutdown may not work. In such cases, it is recommended to put new firmwares in /lib/firmware location and do a reboot.
System memory is carved out for each remote processor core for IPC and for the remote processor's code/data section needs. The default memory carveouts (DMA pools) are shown below.
See the devicetree bindings documentation for more details: :ti-linux-kernel-binding:`remoteproc/ti,k3-r5f-rproc.yaml`
+------------------+--------------------+---------+----------------------------+
| Memory Section | Physical Address | Size | Description |
+==================+====================+=========+============================+
| R5F(mcu) Pool | 0xa0000000 | 1MB | IPC (Virtio/Vring buffers) |
+------------------+--------------------+---------+----------------------------+
| R5F(mcu) Pool | 0xa0100000 | 15MB | R5F externel code/data mem |
+------------------+--------------------+---------+----------------------------+
| R5F(mcu) Pool | 0xa1000000 | 1MB | IPC (Virtio/Vring buffers) |
+------------------+--------------------+---------+----------------------------+
| R5F(mcu) Pool | 0xa1100000 | 15MB | R5F externel code/data mem |
+------------------+--------------------+---------+----------------------------+
| R5F(main) Pool | 0xa2000000 | 1MB | IPC (Virtio/Vring buffers) |
+------------------+--------------------+---------+----------------------------+
| R5F(main) Pool | 0xa2100000 | 15MB | R5F externel code/data mem |
+------------------+--------------------+---------+----------------------------+
| R5F(main) Pool | 0xa3000000 | 1MB | IPC (Virtio/Vring buffers) |
+------------------+--------------------+---------+----------------------------+
| R5F(main) Pool | 0xa3100000 | 15MB | R5F externel code/data mem |
+------------------+--------------------+---------+----------------------------+
root@j7200-evm:~# dmesg | grep Reserved
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a0000000, size 1 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a0100000, size 15 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a1000000, size 1 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a1100000, size 15 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a2000000, size 1 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a2100000, size 15 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a3000000, size 1 MiB
[ 0.000000] Reserved memory: created DMA memory pool at 0x00000000a3100000, size 15 MiB
[ 0.000000] cma: Reserved 32 MiB at 0x00000000fe000000Note
The reserved memory sizes listed above are provided as a reference only and subject to change between releases. For latest memory reservations, please refer to the kernel device tree repository : https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi?h=ti-linux-6.6.y
By default the first 1MB of each pool is used for the Virtio and Vring buffers used to communicate with the remote processor core. The remaining carveout is used for the remote core external memory (program code, data, etc).
Note
The resource table entity (which describes the system resources needed by the remote processor) needs to be at the beginning of the remote processor external memory section.
Sizes and locations for DMA memory carveouts might be updated, e.g. when custom firmware are used. For details on how to adjust the sizes and locations of the remote core pool carveouts, please see section :ref:`changing_the_memory_map`.
The address and size of the DMA memory carveouts needs to match with the MCU R5F external memory section sizes in their respective linker mapfiles.
arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi
reserved_memory: reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;
secure_ddr: optee@9e800000 {
reg = <0x00 0x9e800000 0x00 0x01800000>;
alignment = <0x1000>;
no-map;
};
mcu_r5fss0_core0_dma_memory_region: r5f-dma-memory@a0000000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa0000000 0x00 0x100000>;
no-map;
};
mcu_r5fss0_core0_memory_region: r5f-memory@a0100000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa0100000 0x00 0xf00000>;
no-map;
};
mcu_r5fss0_core1_dma_memory_region: r5f-dma-memory@a1000000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa1000000 0x00 0x100000>;
no-map;
};
mcu_r5fss0_core1_memory_region: r5f-memory@a1100000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa1100000 0x00 0xf00000>;
no-map;
};
main_r5fss0_core0_dma_memory_region: r5f-dma-memory@a2000000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa2000000 0x00 0x100000>;
no-map;
};
main_r5fss0_core0_memory_region: r5f-memory@a2100000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa2100000 0x00 0xf00000>;
no-map;
};
main_r5fss0_core1_dma_memory_region: r5f-dma-memory@a3000000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa3000000 0x00 0x100000>;
no-map;
};
main_r5fss0_core1_memory_region: r5f-memory@a3100000 {
compatible = "shared-dma-pool";
reg = <0x00 0xa3100000 0x00 0xf00000>;
no-map;
};
rtos_ipc_memory_region: ipc-memories@a4000000 {
reg = <0x00 0xa4000000 0x00 0x00800000>;
alignment = <0x1000>;
no-map;
};
};
Warning
Be careful not to overlap carveouts!
Note
The reserved memory sizes listed above are provided as a reference only and subject to change between releases. For latest memory reservations, please refer to the kernel device tree repository : https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi?h=ti-linux-6.6.y