On 21/11/2016 16:49, Andre Przywara wrote:
Hi Alex,
thanks for having a look!
On 21/11/16 15:34, Alexander Graf wrote:
On 20/11/2016 15:56, Andre Przywara wrote:
For boards that call s_init() when the SPL runs, we are expected to
setup an early stack before calling this C function.
Implement the proper AArch64 version of this based on the ARMv7 code.
This allows sunxi boards to setup the basic peripherals even on with a
64-bit SPL.
Signed-off-by: Andre Przywara <[email protected]>
Isn't that what _main in ./arch/arm/lib/crt0_64.S is supposed to do?
That should be used for the SPL flow too, no?
I saw that too, but apparently this one here is a some shortcut for the
SPL. TBH I didn't dare to look too closely, as this seems to be a bit
entangled.
....
---
arch/arm/cpu/armv8/Makefile | 1 +
arch/arm/cpu/armv8/lowlevel_init.S | 44
++++++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
create mode 100644 arch/arm/cpu/armv8/lowlevel_init.S
diff --git a/arch/arm/cpu/armv8/Makefile b/arch/arm/cpu/armv8/Makefile
index dea1465..799a752 100644
--- a/arch/arm/cpu/armv8/Makefile
+++ b/arch/arm/cpu/armv8/Makefile
@@ -25,3 +25,4 @@ obj-$(CONFIG_FSL_LAYERSCAPE) += fsl-layerscape/
obj-$(CONFIG_S32V234) += s32v234/
obj-$(CONFIG_ARCH_ZYNQMP) += zynqmp/
obj-$(CONFIG_TARGET_HIKEY) += hisilicon/
+obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o
diff --git a/arch/arm/cpu/armv8/lowlevel_init.S
b/arch/arm/cpu/armv8/lowlevel_init.S
new file mode 100644
index 0000000..189e35f
--- /dev/null
+++ b/arch/arm/cpu/armv8/lowlevel_init.S
@@ -0,0 +1,44 @@
+/*
+ * A lowlevel_init function that sets up the stack to call a C
function to
+ * perform further init.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <asm-offsets.h>
+#include <config.h>
+#include <linux/linkage.h>
+
+ENTRY(lowlevel_init)
+ /*
+ * Setup a temporary stack. Global data is not available yet.
+ */
+#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
+ ldr w0, =CONFIG_SPL_STACK
+#else
+ ldr w0, =CONFIG_SYS_INIT_SP_ADDR
+#endif
+ bic sp, x0, #0xf /* 16-byte alignment for ABI compliance */
+
+ /*
+ * Save the old LR(passed in x29) and the current LR to stack
+ */
+ stp x29, x30, [sp, #-16]!
+
+ /*
+ * Call the very early init function. This should do only the
+ * absolute bare minimum to get started. It should not:
+ *
+ * - set up DRAM
+ * - use global_data
+ * - clear BSS
+ * - try to start a console
+ *
+ * For boards with SPL this should be empty since SPL can do all of
+ * this init in the SPL board_init_f() function which is called
+ * immediately after this.
So this comment says that s_init shouldn't even be used for SPL and
instead we should use board_init_f which is what crt0 calls.
Yes, that is a good point. So the sunxi port seemed to ignore this
recommendation and do it in its own way (TM).
Frankly I didn't want to fix this one too at this point, so I just went
ahead with filling the 64-bit gaps.
But I agree that this should be fixed eventually. The line above:
+obj-$(CONFIG_ARCH_SUNXI) += lowlevel_init.o
hints already that something is not really right here, as SUNXI is the
only user of this rather generic function.
If I find some spare time (haha), I might take a look, otherwise: be my
guest ;-)
IIRC in my SPL port (that I can't find anymore) I just called s_init
from board_init_f.
Alex
_______________________________________________
U-Boot mailing list
[email protected]
http://lists.denx.de/mailman/listinfo/u-boot
