[U-Boot] [PATCH 030/172] arm: socfpga: misc: Fix warm reset

Marek Vasut
2015-07-27T20:49:53Z

Write necessary magic value into the Warm Boot from ON-Chip RAM
group Enable register to enable Warm reset support. Instead of
doing this in the reset_cpu() function, we do it in arch early
init to avoid breaking old kernel code which expects this magic
value to be already written into this register.

This magic is originally excavated from common/spl/spl.c in the
u-boot port from altera, where this value was written just before
the SPL jumped to actual U-Boot in the RAM.

Signed-off-by: Marek Vasut <marex@denx.de>
---
arch/arm/mach-socfpga/misc.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/arm/mach-socfpga/misc.c b/arch/arm/mach-socfpga/misc.c
index f03689c..5175195 100644
--- a/arch/arm/mach-socfpga/misc.c
+++ b/arch/arm/mach-socfpga/misc.c
@@ -193,6 +193,16 @@ static uint32_t iswgrp_handoff[8];
int arch_early_init_r(void)
{
int i;
+
+ /*
+ * Write magic value into magic register to unlock support for
+ * issuing warm reset. The ancient kernel code expects this
+ * value to be written into the register by the bootloader, so
+ * to support that old code, we write it here instead of in the
+ * reset_cpu() function just before reseting the CPU.
+ */
+ writel(0xae9efebc, &sysmgr_regs->romcodegrp_warmramgrp_enable);
+
for (i = 0; i < 8; i++) /* Cache initial SW setting regs */
iswgrp_handoff[i] = readl(&sysmgr_regs->iswgrp_handoff[i]);

--
2.1.4