[PATCH v2 2/6] armv8: spin_table: add hook for booting cores

[Sam Day via B4 Relay]

From: Sam Day <me at samcday.com>

Introduce the weak symbol spin_table_boot_cpu, which is called by
spin_table_update_dt during pre-boot FDT fixup phase for each CPU that
has enable-method="spin-table".

This saves the board/arch code from needing to scan the DT looking for
CPUs to boot, and also makes it easier to bring the secondary CPUs online
as late as possible.

Reviewed-by: Tom Rini <trini at konsulko.com>
Signed-off-by: Sam Day <me at samcday.com>
---
 arch/arm/cpu/armv8/spin_table.c   | 20 ++++++++++++++++++++
 arch/arm/include/asm/spin_table.h |  1 +
 2 files changed, 21 insertions(+)

diff --git a/arch/arm/cpu/armv8/spin_table.c b/arch/arm/cpu/armv8/spin_table.c
index 5ba20efa33b..32bf680f02c 100644
--- a/arch/arm/cpu/armv8/spin_table.c
+++ b/arch/arm/cpu/armv8/spin_table.c
@@ -8,11 +8,18 @@
 #include <linux/libfdt.h>
 #include <asm/spin_table.h>
 
+int __weak spin_table_boot_cpu(void *fdt, int cpu_offset)
+{
+	return 0;
+}
+
 int spin_table_update_dt(void *fdt)
 {
 	int cpus_offset, offset;
 	const char *prop;
+	const void *release_addr;
 	int ret;
+	int found_cpus = 0;
 	unsigned long rsv_addr = (unsigned long)&spin_table_reserve_begin;
 	unsigned long rsv_size = &spin_table_reserve_end -
 						&spin_table_reserve_begin;
@@ -45,12 +52,25 @@ int spin_table_update_dt(void *fdt)
 		if (!prop || strcmp(prop, "cpu"))
 			continue;
 
+		release_addr = fdt_getprop(fdt, offset, "cpu-release-addr", NULL);
+		if (release_addr)
+			continue;
+
+		found_cpus = 1;
+
+		ret = spin_table_boot_cpu(fdt, offset);
+		if (ret)
+			return ret;
+
 		ret = fdt_setprop_u64(fdt, offset, "cpu-release-addr",
 				(unsigned long)&spin_table_cpu_release_addr);
 		if (ret)
 			return -ENOSPC;
 	}
 
+	if (!found_cpus)
+		return 0;
+
 	ret = fdt_add_mem_rsv(fdt, rsv_addr, rsv_size);
 	if (ret)
 		return -ENOSPC;
diff --git a/arch/arm/include/asm/spin_table.h b/arch/arm/include/asm/spin_table.h
index 8fc61237e07..3c422046b83 100644
--- a/arch/arm/include/asm/spin_table.h
+++ b/arch/arm/include/asm/spin_table.h
@@ -10,5 +10,6 @@ extern char spin_table_reserve_begin;
 extern char spin_table_reserve_end;
 
 int spin_table_update_dt(void *fdt);
+int spin_table_boot_cpu(void *fdt, int cpu_offset);
 
 #endif /* __ASM_SPIN_TABLE_H__ */

-- 
2.54.0