We boot the kernel in non-secure mode and by default access to
the CCI device is not enabled for non-secure access, so we must
enable this if we want Linux to manage CPU hotplug on big.LITTLE
models.
Signed-off-by: Jon Medhurst <tixy@xxxxxxxxxx>
---
Changes since V1:
- Add a DSB instructions
semi_loader.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/semi_loader.c b/semi_loader.c
index f8be94d..51ffaf6 100644
--- a/semi_loader.c
+++ b/semi_loader.c
@@ -263,6 +263,13 @@ static void init_cci(unsigned cci)
/* Wait while change pending bit of status register is set */
while(io32(cci+0xc) & 0x1)
{}
+
+ /*
+ * Enable non-secure access to CCI and use a DSB ensure this takes
+ * effect before such accesses are made.
+ */
+ io32(cci+0x8) = 1;
+ asm volatile ("dsb" : : : "memory");
}
static void configure_from_fdt(struct loader_info *info)
--
1.7.10.4
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