[U-Boot] [PATCH] ARM: socfpga: Assure correct ACTLR configuration

[Marek Vasut]

Make sure the ARM ACTLR register has correct configuration, otherwise
the Linux kernel refuses to boot. In particular, the "Write Full Line
of Zeroes" bit must be cleared.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Chin Liang See <chin.liang.see at intel.com>
Cc: Dinh Nguyen <dinguyen at kernel.org>
---
NOTE: This gem was well hidden in the Altera U-Boot fork and is really needed.
      What is not entirely clear to me is WHY ? So why is this needed ?

 arch/arm/mach-socfpga/board.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-socfpga/board.c b/arch/arm/mach-socfpga/board.c
index 189e12a668..ffdabc04fc 100644
--- a/arch/arm/mach-socfpga/board.c
+++ b/arch/arm/mach-socfpga/board.c
@@ -18,7 +18,18 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-void s_init(void) {}
+void s_init(void) {
+	/*
+	 * Preconfigure ACTLR, make sure Write Full Line of Zeroes is disabled.
+	 * This is optional on CycloneV / ArriaV.
+	 * This is mandatory on Arria10, otherwise Linux refuses to boot.
+	 */
+	asm volatile(
+		"mcr p15, 0, %0, c1, c0, 1\n"
+		"isb\n"
+		"dsb\n"
+	::"r"(0x44));
+}
 
 /*
  * Miscellaneous platform dependent initialisations
-- 
2.17.0