svn commit: r298477 - in head/sys: conf riscv/riscv

[Ruslan Bukin]

Author: br
Date: Fri Apr 22 16:15:58 2016
New Revision: 298477
URL: https://svnweb.freebsd.org/changeset/base/298477

Log:
  Clear the DDR memory. This should be done by bootloaders,
  but they have no such feature yet.
  
  This fixes operation on Rocket Core and lowRISC.

Modified:
  head/sys/conf/options.riscv
  head/sys/riscv/riscv/locore.S

Modified: head/sys/conf/options.riscv
==============================================================================
--- head/sys/conf/options.riscv	Fri Apr 22 15:12:05 2016	(r298476)
+++ head/sys/conf/options.riscv	Fri Apr 22 16:15:58 2016	(r298477)
@@ -2,3 +2,4 @@
 
 RISCV				opt_global.h
 VFP				opt_global.h
+DDR_CLEAR_SIZE			opt_global.h

Modified: head/sys/riscv/riscv/locore.S
==============================================================================
--- head/sys/riscv/riscv/locore.S	Fri Apr 22 15:12:05 2016	(r298476)
+++ head/sys/riscv/riscv/locore.S	Fri Apr 22 16:15:58 2016	(r298477)
@@ -126,6 +126,17 @@ _start:
 	csrr	a0, mhartid
 	bnez	a0, mpentry
 
+#if defined(DDR_CLEAR_SIZE)
+	/* Clear DDR memory */
+	la	t0, _end
+	li	t1, DDR_CLEAR_SIZE
+1:
+	sd	zero, 0(t0)
+	addi	t0, t0, 8
+	bltu	t0, t1, 1b
+	/* End */
+#endif
+
 	/* Build event queue for current core */
 	build_ring