This adds support for booting entirely from JTAG while using a hard-coded RCW. With these steps, it is not necessary to program a "good" RCW using CodeWarrior. The method here can be performed with any JTAG adapter supported by OpenOCD, including the on-board CMSIS-DAP (albeit very slowly).
These steps require LS1046A support in OpenOCD, which was added in [1].
[1] https://sourceforge.net/p/openocd/code/ci/5b70c1f679755677c925b4e6dd2c3d8be4...
Signed-off-by: Sean Anderson sean.anderson@seco.com ---
Changes in v3: - Add dummy device number for hostfs
arch/arm/cpu/armv8/fsl-layerscape/spl.c | 2 + board/freescale/ls1046ardb/ls1046ardb.c | 10 ++++ doc/board/nxp/ls1046ardb.rst | 71 +++++++++++++++++++++++++ doc/usage/semihosting.rst | 3 +- include/configs/ls1046ardb.h | 2 + 5 files changed, 87 insertions(+), 1 deletion(-)
diff --git a/arch/arm/cpu/armv8/fsl-layerscape/spl.c b/arch/arm/cpu/armv8/fsl-layerscape/spl.c index 564cc27c8b..1a7dde30a5 100644 --- a/arch/arm/cpu/armv8/fsl-layerscape/spl.c +++ b/arch/arm/cpu/armv8/fsl-layerscape/spl.c @@ -27,6 +27,8 @@ DECLARE_GLOBAL_DATA_PTR;
u32 spl_boot_device(void) { + if (IS_ENABLED(CONFIG_SPL_SEMIHOSTING)) + return BOOT_DEVICE_SMH; #ifdef CONFIG_SPL_MMC return BOOT_DEVICE_MMC1; #endif diff --git a/board/freescale/ls1046ardb/ls1046ardb.c b/board/freescale/ls1046ardb/ls1046ardb.c index d0abfe8869..9af7cf763b 100644 --- a/board/freescale/ls1046ardb/ls1046ardb.c +++ b/board/freescale/ls1046ardb/ls1046ardb.c @@ -7,6 +7,8 @@ #include <i2c.h> #include <fdt_support.h> #include <init.h> +#include <semihosting.h> +#include <serial.h> #include <asm/global_data.h> #include <asm/io.h> #include <asm/arch/clock.h> @@ -27,6 +29,14 @@
DECLARE_GLOBAL_DATA_PTR;
+struct serial_device *default_serial_console(void) +{ +#if IS_ENABLED(CONFIG_SEMIHOSTING_SERIAL) + return &serial_smh_device; +#endif + return &eserial1_device; +} + int board_early_init_f(void) { fsl_lsch2_early_init_f(); diff --git a/doc/board/nxp/ls1046ardb.rst b/doc/board/nxp/ls1046ardb.rst index e4499a13fb..08d81e385a 100644 --- a/doc/board/nxp/ls1046ardb.rst +++ b/doc/board/nxp/ls1046ardb.rst @@ -110,6 +110,77 @@ SD boot and eMMC boot ``{ SW5[0:8], SW4[0] }`` should be ``0010_0000_0``. eMMC is selected only if there is no SD card in the slot.
+JTAG boot +^^^^^^^^^ + +To recover a bricked board, or to perform initial programming, the ls1046 +supports using two hard-coded Reset Configuration Words (RCWs). Unfortunately, +this configuration disables most functionality, including the uarts and ethernet. +However, the SD/MMC and flash controllers are still functional. To get around +the lack of a serial console, we will use ARM semihosting instead. When +enabled, OpenOCD will interpret certain instructions as calls to the host +operating system. This allows U-Boot to use the console, read/write files, or +run arbitrary commands (!). + +When configuring U-Boot, ensure that ``CONFIG_SEMIHOSTING``, +``CONFIG_SPL_SEMIHOSTING``, and ``CONFIG_SEMIHOSTING_SERIAL`` are enabled. +``{ SW5[0:8], SW4[0] }`` should be ``0100_1111_0``. Additionally, ``SW4[7]`` +should be set to ``0``. Connect to the "console" USB connector on the front of +the enclosure. + +Create a new file called ``u-boot.tcl`` (or whatever you choose) with the +following contents:: + + # Load the configuration for the LS1046ARDB + source [find board/nxp_rdb-ls1046a.cfg] + # Initialize the scan chain + init + # Stop the processor + halt + # Enable semihosting + arm semihosting enable + # Load U-Boot SPL + load_image spl/u-boot-spl 0 elf + # Start executing SPL at the beginning of OCRAM + resume 0x10000000 + +Then, launch openocd like:: + + openocd -f u-boot.tcl + +You should see the U-boot SPL banner followed by the banner for U-Boot proper +in the output of openocd. The CMSIS-DAP adapter is slow, so this can take a +long time. If you don't see it, something has gone wrong. After a while, you +should see the prompt. You can load an image using semihosting by running:: + + => load hostfs - $loadaddr <name of file> + +Note that openocd's terminal is "cooked," so commands will only be sent to +U-Boot when you press enter, and all commands will be echoed twice. +Additionally, openocd will block when waiting for input, ignoring gdb, JTAG +events, and Ctrl-Cs. To make openocd process these events, just hit enter. + +Using an external JTAG adapter +"""""""""""""""""""""""""""""" + +The CMSIS-DAP adapter can be rather slow. To speed up booting, use an external +JTAG adapter. The following examples assume you are using a J-Link, though any +adapter supported by OpenOCD will do. Ensure that ``SW4[7]`` is ``1``. Attach +your jtag adapter to J22. Modify ``u-boot.tcl`` and replace the first two lines +with the following:: + + # Load the J-Link configuration (or whatever your adapter is) + source [find interface/jlink.cfg] + # Use JTAG, since the J-Link also supports SWD + transport select jtag + # The reset pin resets the whole CPU + reset_config srst_only + # Load the LS1046A config + source [find target/ls1046a.cfg] + +You can proceed as normal through the rest of the steps above. I got a speedup +of around 100x by using a J-Link. + Debug UART ----------
diff --git a/doc/usage/semihosting.rst b/doc/usage/semihosting.rst index 1d793983a7..6a280b455e 100644 --- a/doc/usage/semihosting.rst +++ b/doc/usage/semihosting.rst @@ -62,7 +62,8 @@ so you will need to enable it:: 'arm semihosting enable' -c resume
Note that enabling semihosting can only be done after attaching to the -board with ``init``, and must be done while the CPU is halted. +board with ``init``, and must be done while the CPU is halted. For a more +extended example, refer to the :ref:`LS1046ARDB docs <ls1046ardb_jtag>`.
Loading files ------------- diff --git a/include/configs/ls1046ardb.h b/include/configs/ls1046ardb.h index 04c3ad02c8..df699bca34 100644 --- a/include/configs/ls1046ardb.h +++ b/include/configs/ls1046ardb.h @@ -140,6 +140,8 @@ #endif #endif
+#define CONFIG_SPL_FS_LOAD_PAYLOAD_NAME "u-boot.img" + #include <asm/fsl_secure_boot.h>
#endif /* __LS1046ARDB_H__ */