Hi Tim,
actually not sure why this was off the list. Let me add it.
On 7/2/26 13:26, Michal Simek wrote:
On 7/2/26 10:57, Tim Ouyang wrote:
On Mon, Jun 29, 2026 at 11:00:40AM +0200, Michal Simek wrote:
On 5/11/26 10:31, Michal Simek wrote:
Building on commit c64fc632a86a ("riscv: cpu: Use CONFIG_IS_ENABLED(CPU)
instead of plain ifdef"), add an early return in riscv_cpu_setup() when
CONFIG_CPU is not enabled. This allows platforms to save code space in
SPL by disabling CONFIG_SPL_CPU.
Without this patch, building U-Boot with CONFIG_CPU=n and CONFIG_EVENT=y
is broken: riscv_cpu_setup() is registered as an EVT_DM_POST_INIT_F event
spy, and when the CPU uclass is unavailable uclass_find_first_device()
returns no device, so the function returns -ENODEV. That in turn makes
event_notify_null() in dm_init_and_scan() fail and triggers a boot hang
("initcall initf_dm() failed"). Returning 0 early avoids that failure.
The compiler's dead-code elimination combined with --gc-sections
removes the unreachable code and all associated static data,
achieving significant size reduction without preprocessor guards:
spl/u-boot-spl:all -4332 spl/u-boot-spl:rodata -2872
spl/u-boot-spl:text -1460
Signed-off-by: Michal Simek <[email protected]>
Reviewed-by: Yao Zi <[email protected]>
---
Changes in v2:
- extend commit message
arch/riscv/cpu/cpu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index bbadd0c9a469..3bec7c7cb6d0 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -638,6 +638,9 @@ int riscv_cpu_setup(void)
const char *isa, **exts;
struct udevice *dev;
+ if (!CONFIG_IS_ENABLED(CPU))
+ return 0;
+
uclass_find_first_device(UCLASS_CPU, &dev);
if (!dev) {
debug("unable to find the RISC-V cpu device\n");
Can you please take it directly to next branch?
Thanks,
Michal
Hi Michal,
The new RISC-V maintainer here. It seems your patch does not fix the
issue. I tested it with the following steps:
- mkdir -p $OUTPUT/test
- make qemu-riscv64_spl_defconfig O=$OUTPUT/test CROSS_COMPILE=riscv64-linux-
- make menuconfig O=$OUTPUT/test CROSS_COMPILE=riscv64-linux-
Disable CONFIG_CPU manually
- make O=$OUTPUT/test CROSS_COMPILE=riscv64-linux-
The build fails with:
riscv64-linux-ld: common/board_f.o: in function `initcall_run_f':
/work/u-boot-riscv/common/board_f.c:921:(.text.board_init_f+0x166): undefined
reference to `print_cpuinfo'
riscv64-linux-ld: drivers/timer/riscv_aclint_timer.o: in function
`riscv_aclint_timer_probe':
/work/u-boot-riscv/drivers/timer/riscv_aclint_timer.c:77:
(.text.riscv_aclint_timer_probe+0x24): undefined reference to
`timer_timebase_fallback'
make[1]: *** [/work/u-boot-riscv/Makefile:2112: u-boot] Error 1
Please correct me if I missed something.
It is not valid configuration because dependencies are not properly described in
Kconfig.
drivers/timer/riscv_aclint_timer.c
calls timer_timebase_fallback() which is defined in drivers/timer/timer-uclass.c
as
90 #if CONFIG_IS_ENABLED(CPU)
91 int timer_timebase_fallback(struct udevice *dev)
92 {
It means for this risc-v configuration in Kconfig when aclint_timer is selected
it has to depends on CONFIG_CPU/CONFIG_SPL_CPU or should select it by default.
Microblaze-V is not using this timer that's why no problem to disable it.
And the second issue around print_cpuinfo. When you disable CPU likely you need
to also disable CONFIG_DISPLAY_CPUINFO. CONFIG_CPU is uclass but if you grep it
I wouldn't be surprised that there are still platform which are able to print
information about cpu without enabling cpu uclass. That's why there is not
dependency between CONFIG_DISPLAY_CPUINFO and CONFIG_CPU.
Any reaction?
Thanks,
Michal
