From: Guenter Roeck <li...@roeck-us.net>
The cpu-idle-states property causes a hard boot hang. Rather than documenting
the workaround, perform the removal from the devicetree automatically.
Signed-off-by: Guenter Roeck <li...@roeck-us.net>
Signed-off-by: Bernhard Beschow <shen...@gmail.com>
[Bernhard: split patch, update documentation, adapt commit message]
Signed-off-by: Bernhard Beschow <shen...@gmail.com>
Message-ID: <20250405214900.7114-3-shen...@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
docs/system/arm/imx8mp-evk.rst | 12 ++----------
hw/arm/imx8mp-evk.c | 14 ++++++++++++++
2 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/docs/system/arm/imx8mp-evk.rst b/docs/system/arm/imx8mp-evk.rst
index 00527b0cbed..b2f7d29ade5 100644
--- a/docs/system/arm/imx8mp-evk.rst
+++ b/docs/system/arm/imx8mp-evk.rst
@@ -35,7 +35,7 @@ Direct Linux Kernel Boot
Probably the easiest way to get started with a whole Linux system on the
machine
is to generate an image with Buildroot. Version 2024.11.1 is tested at the time
-of writing and involves three steps. First run the following commands in the
+of writing and involves two steps. First run the following commands in the
toplevel directory of the Buildroot source tree:
.. code-block:: bash
@@ -50,14 +50,6 @@ it and resize the SD card image to a power of two:
$ qemu-img resize sdcard.img 256M
-Finally, the device tree needs to be patched with the following commands which
-will remove the ``cpu-idle-states`` properties from CPU nodes:
-
-.. code-block:: bash
-
- $ dtc imx8mp-evk.dtb | sed '/cpu-idle-states/d' > imx8mp-evk-patched.dts
- $ dtc imx8mp-evk-patched.dts -o imx8mp-evk-patched.dtb
-
Now that everything is prepared the machine can be started as follows:
.. code-block:: bash
@@ -65,6 +57,6 @@ Now that everything is prepared the machine can be started as
follows:
$ qemu-system-aarch64 -M imx8mp-evk -smp 4 -m 3G \
-display none -serial null -serial stdio \
-kernel Image \
- -dtb imx8mp-evk-patched.dtb \
+ -dtb imx8mp-evk.dtb \
-append "root=/dev/mmcblk2p2" \
-drive file=sdcard.img,if=sd,bus=2,format=raw,id=mmcblk2
diff --git a/hw/arm/imx8mp-evk.c b/hw/arm/imx8mp-evk.c
index f17d5db466d..3bbf2bfbea3 100644
--- a/hw/arm/imx8mp-evk.c
+++ b/hw/arm/imx8mp-evk.c
@@ -15,6 +15,19 @@
#include "system/qtest.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
+#include <libfdt.h>
+
+static void imx8mp_evk_modify_dtb(const struct arm_boot_info *info, void *fdt)
+{
+ int offset;
+
+ /* Remove cpu-idle-states property from CPU nodes */
+ offset = fdt_node_offset_by_compatible(fdt, -1, "arm,cortex-a53");
+ while (offset >= 0) {
+ fdt_nop_property(fdt, offset, "cpu-idle-states");
+ offset = fdt_node_offset_by_compatible(fdt, offset, "arm,cortex-a53");
+ }
+}
static void imx8mp_evk_init(MachineState *machine)
{
@@ -32,6 +45,7 @@ static void imx8mp_evk_init(MachineState *machine)
.board_id = -1,
.ram_size = machine->ram_size,
.psci_conduit = QEMU_PSCI_CONDUIT_SMC,
+ .modify_dtb = imx8mp_evk_modify_dtb,
};
s = FSL_IMX8MP(object_new(TYPE_FSL_IMX8MP));
--
2.47.1
