[PATCH v5] docs/user: add docs for riscv/kendrytek210 BSP variant

Alan Cudmore alan.cudmore at gmail.com
Mon Apr 3 14:46:58 UTC 2023


This patch adds the documentation for building and running RTEMS on the Kendryte K210 RISC-V SoC.
The generic riscv introducion was re-arranged to list the multilib variants then the specific
hardware targets. In addition a couple of errors were fixed for the generic QEMU commands.

V2 corrected a typo, expanded K210 Console UART parameters, and addded a hyperlink to renode.io install
instructions.

V3 clarified the multilib variant description, clarified the multilib variant reference platform, and
corrected capitalization on SiFive.

V4 improves the instructions for running the K210 BSP on the Renode.io simulator.

V5 cleaned up the text to be no more than 80 characters per line.

Closes #4876
---
 user/bsps/bsps-riscv.rst | 182 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 159 insertions(+), 23 deletions(-)

diff --git a/user/bsps/bsps-riscv.rst b/user/bsps/bsps-riscv.rst
index 41f369f..aac2f7c 100644
--- a/user/bsps/bsps-riscv.rst
+++ b/user/bsps/bsps-riscv.rst
@@ -8,7 +8,8 @@ riscv (RISC-V)
 riscv
 =====
 
-This BSP offers 12 variants:
+**Each variant in this first group corresponds to a GCC multilib option with
+different RISC-V standard extensions.**
 
 * rv32i
 
@@ -30,23 +31,26 @@ This BSP offers 12 variants:
 
 * rv64imafdc
 
-* frdme310arty
+Each variant reflects an ISA with ABI and code model choice. All rv64 BSPs have
+medany code model by default, while rv32 BSPs are medlow. The reason is that
+RV32 medlow can access the entire 32-bit address space, while RV64 medlow can
+only access addresses below 0x80000000. With RV64 medany, it's possible to
+perform accesses above 0x80000000. The BSP must be started in machine mode.
 
-* mpfs64imafdc
+The reference platforms for the rv* variants include the QEMU `virt` and `spike`
+machines and the Spike RISC-V ISA simulator.
 
-Each rv* variant corresponds to a GCC multilib.  A particular variant reflects an
-ISA with ABI and code model choice. All rv64 BSPs have medany code model by
-default, while rv32 BSPs are medlow. The reason is that RV32 medlow can access
-the entire 32-bit address space, while RV64 medlow can only access addresses
-below 0x80000000. With RV64 medany, it's possible to perform accesses above
-0x80000000.
+**The BSP also provides the following variants for specific hardware targets:**
 
-The BSP must be started im machine mode.
+* frdme310arty - The reference platform for this variant is the Arty FPGA board
+  with the SiFive Freedom E310 reference design.
 
-The reference platform for this BSP is the QEMU `virt` machine.
+* mpfs64imafdc - The reference platform for this variant is the Microchip
+  PolarFire SoC Icicle Kit.
+
+* kendrytek210 - The reference platform for this variant is the Kendryte K210
+  SoC on the Sipeed MAiX Bit or MAiXDuino board.
 
-The reference platform for the mpfs64imafdc BSP variant is the Microchip
-PolarFire SoC Icicle Kit.
 
 Build Configuration Options
 ---------------------------
@@ -77,33 +81,41 @@ configuration INI file. The ``waf`` defaults can be used to inspect the values.
     The path to the header file containing the device tree blob.
 
 ``BSP_CONSOLE_BAUD``
-    The default baud for console driver devices (default 115200).
+    The default baud for console driver devices (default is 115200).
 
 ``RISCV_MAXIMUM_EXTERNAL_INTERRUPTS``
      The maximum number of external interrupts supported by the BSP (default
-     64).
+     is 64).
 
 ``RISCV_ENABLE_HTIF_SUPPORT``
      Enable the Host/Target Interface (HTIF) support (enabled by default).
 
 ``RISCV_CONSOLE_MAX_NS16550_DEVICES``
-     The maximum number of NS16550 devices supported by the console driver (2
-     by default).
+     The maximum number of NS16550 devices supported by the console driver
+     (default is 2).
+
+``RISCV_ENABLE_SIFIVE_UART_SUPPORT``
+     Enable the SiFive console UART (disabled by default).
 
 ``RISCV_RAM_REGION_BEGIN``
-     The begin of the RAM region for linker command file (default is 0x80000000).
+     The begin of the RAM region for linker command file
+     (default is 0x80000000).
 
 ``RISCV_RAM_REGION_SIZE``
      The size of the RAM region for linker command file (default 64MiB).
 
 ``RISCV_ENABLE_FRDME310ARTY_SUPPORT``
      Enables support sifive Freedom E310 Arty board if defined to a non-zero
-     value,otherwise it is disabled (disabled by default)
+     value,otherwise it is disabled (disabled by default).
 
 ``RISCV_ENABLE_MPFS_SUPPORT``
      Enables support Microchip PolarFire SoC if defined to a non-zero
      value, otherwise it is disabled (disabled by default).
 
+``RISCV_ENABLE_KENDRYTE_K210_SUPPORT``
+     Enables support for the Kendtryte K210 SoC if defined to a non-zero
+     value, otherwise it is disabled (disabled by default).
+
 ``RISCV_BOOT_HARTID``
      The boot hartid (processor number) of risc-v cpu by default 0.
 
@@ -123,15 +135,15 @@ The clock driver uses the CLINT timer.
 Console Driver
 --------------
 
-The console driver supports devices compatible to
+The console driver supports devices compatible to:
 
 * "ucb,htif0" (depending on the ``RISCV_ENABLE_HTIF_SUPPORT`` BSP option),
 
-* "ns16550a" (see ``RISCV_CONSOLE_MAX_NS16550_DEVICES`` BSP option), and
+* "ns16550a" (see ``RISCV_CONSOLE_MAX_NS16550_DEVICES`` BSP option),
 
-* "ns16750" (see ``RISCV_CONSOLE_MAX_NS16550_DEVICES`` BSP option).
+* "ns16750" (see ``RISCV_CONSOLE_MAX_NS16550_DEVICES`` BSP option), and
 
-* "sifive,uart0" (see ``RISCV_ENABLE_FRDME310ARTY_SUPPORT`` BSP option).
+* "sifive,uart0" (see ``RISCV_ENABLE_SIFIVE_UART_SUPPORT`` BSP option).
 
 They are initialized according to the device tree.  The console driver does not
 configure the pins or peripheral clocks.  The console device is selected
@@ -145,11 +157,13 @@ and spike machines. For instance, to run the ``rv64imafdc`` BSP with the
 following "config.ini" file.
 
 .. code-block:: none
+
     [riscv/rv64imafdc]
 
 Run the following QEMU command.
 
 .. code-block:: shell
+
     $ qemu-system-riscv64 -M virt -nographic -bios $RTEMS_EXE
     $ qemu-system-riscv64 -M spike -nographic -bios $RTEMS_EXE
 
@@ -160,11 +174,13 @@ For instance, to run the ``rv64imafdc`` BSP with the following
 "config.ini" file.
 
 .. code-block:: none
+
     [riscv/rv64imafdc]
 
 Run the following Spike command.
 
 .. code-block:: shell
+
     $ spike --isa=rv64imafdc $RTEMS_EXE
 
 Unlike QEMU, Spike supports enabling/disabling a subset of the imafdc extensions
@@ -277,6 +293,126 @@ Serial terminal UART1 displays the SMP example messages
 
     *** END OF TEST SMP 1 ***
 
+Kendryte K210
+-------------
+
+The Kendryte K210 SoC is a dual core 64-bit RISC-V SoC with an AI NPU,
+built in SRAM, and a variety of peripherals. Currently just the console UART,
+interrupt controller, and timer are supported.
+
+The device tree blob is embedded in the ``kendrytek210`` BSP variant by default.
+When the kendrytek210 BSP variant is selected, ``BSP_DTB_IS_SUPPORTED`` enabled
+and the DTB header path ``BSP_DTB_HEADER_PATH`` is set to
+``bsp/kendryte-k210-dtb.h``.
+
+The ``kendrytek210`` BSP variant has been tested on the following simulator and
+boards:
+
+* Renode.io simulator using the Kendrtye k210 model
+* Sipeed MAix BiT board
+* Sipeed MaixDuino board
+* Sipeed MAiX Dock board
+
+**Building the Kendryte K210 BSP**
+
+Configuration file ``config.ini``:
+
+.. code-block:: none
+
+    [riscv/kendrytek210]
+    RTEMS_SMP = True
+
+Build RTEMS:
+
+.. code-block:: shell
+
+    $ ./waf configure --prefix=$HOME/rtems-start/rtems/6
+    $ ./waf
+
+**Flash an executable to the Sipeed MAix BiT or MAixDuino board**
+
+Binary images can be flashed to the Sipeed boards through the USB port using
+the kflash.py utility available from the python pip utility.
+
+.. code-block:: shell
+
+    $ riscv-rtems6-objcopy -Obinary ticker.exe ticker.bin
+    $ kflash.py --uart /dev/ttyUSB0 ticker.bin
+
+After the image is flashed, the RTEMS image will automatically boot. It will
+also run when the board is reset or powered through the USB cable. The USB
+port provides the power and console UART. Plug the USB cable into a host PC
+and bring up a terminal emulator at 115200 baud, 8 data bits, 1 stop bit, no
+parity, and no flow control. On Linux the UART device is often ``/dev/ttyUSB0``.
+
+**Run a RTEMS application on the Renode.io simulator**
+
+RTEMS executables compiled with the kendrytek210 BSP can run on the renode.io
+simulator using the built-in K210 model. The simulator currently supports the
+console UART, interrupt controller, and timer.
+
+To install renode.io please refer to the `installation instructions <https://github.com/renode/renode#installation>`_.
+Once installed, save the following file as `k210_rtems.resc`.
+
+.. code-block:: shell
+
+   using sysbus
+
+   $bin?=@ticker.exe
+
+   mach create "K210"
+
+   machine LoadPlatformDescription @platforms/cpus/kendryte_k210.repl
+
+   showAnalyzer uart
+
+   sysbus Tag <0x50440000 0x10000> "SYSCTL"
+   sysbus Tag <0x50440018 0x4> "pll_lock" 0xFFFFFFFF
+   sysbus Tag <0x5044000C 0x4> "pll1"
+   sysbus Tag <0x50440008 0x4> "pll0"
+   sysbus Tag <0x50440020 0x4> "clk_sel0"
+   sysbus Tag <0x50440028 0x4> "clk_en_cent"
+   sysbus Tag <0x5044002c 0x4> "clk_en_peri"
+
+   macro reset
+   """
+      sysbus LoadELF $bin
+   """
+   runMacro $reset
+
+After saving the above file in in the same directory as your RTEMS ELF images,
+start renode and load the `k210_rtems.resc` script to start the emulation.
+
+.. code-block:: shell
+
+    (monitor) s @k210_rtems.resc
+
+You should see a renode UART window and the RTEMS ticker example output. If
+you want to run a different RTEMS image, you can edit the file or enter the
+following on the renode console.
+
+.. code-block:: shell
+
+    (monitor) $bin=@smp08.exe
+    (monitor) s @k210_rtems.resc
+
+The above example will run the SMP08 example instead of ticker.
+
+**Generating the Device Tree Header**
+
+The kendrytek210 BSP uses a built in device tree blob. If additional peripheral
+support is added to the BSP, the device tree may need to be updated. After
+editing the device tree source, compile it to a device tree blob with the
+following command:
+
+.. code-block:: shell
+
+    $ dtc -O dtb -b 0 -o kendryte-k210.dtb kendryte-k210.dts
+
+The dtb file can then be converted to a C array using the rtems-bin2c tool.
+The data for the device tree binary can then replace the existing device
+tree binary data in the ``kendryte-k210-dtb.h`` header file.
+
 noel
 ====
 
-- 
2.25.1



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