arc: implement slave cores kick-start for Linux kernel
With new SMP-enabled CPUs with ARC HS38 cores and corresponding support
in Linux kernel it's required to add basic SMP support in U-Boot.
Currently we assume the one and only core starts execution after
power-on. So most of things in U-Boot is handled in UP mode.
But when U-Boot is used for loading and starting Linux kernel right
before jumping to kernel's entry point U-Boot:
[1] Sets all slave cores to jump to the same address [kernel's entry
point]
[2] Really starts all slav cores
In ARC's implemetation of SMP in Linux kernel all cores are supposed to
run the same start-up code. But only core with ID 0 (master core)
processes further while others are looping waiting for master core to
complete some initialization.
That means it's safe to un-pause slave cores and let them execute kernel
- they will wait for master anyway.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/lib/bootm.c b/arch/arc/lib/bootm.c
index d185a50..04d9d9c 100644
--- a/arch/arc/lib/bootm.c
+++ b/arch/arc/lib/bootm.c
@@ -53,6 +53,9 @@
hang();
}
+__weak void smp_set_core_boot_addr(unsigned long addr, int corenr) {}
+__weak void smp_kick_all_cpus(void) {}
+
/* Subcommand: GO */
static void boot_jump_linux(bootm_headers_t *images, int flag)
{
@@ -80,6 +83,9 @@
r2 = (unsigned int)getenv("bootargs");
}
+ smp_set_core_boot_addr((unsigned long)kernel_entry, -1);
+ smp_kick_all_cpus();
+
if (!fake)
kernel_entry(r0, 0, r2);
}