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]);