ARM: exynos: add debug_ll_io_init() call in exynos_init_io()

If the early MMU mapping of the UART happens to get booted out of the
TLB between the start of paging_init() and when we finally re-add the
UART at the very end of s3c_init_cpu(), we'll get a hang at bootup if
we've got early_printk enabled.  Avoid this hang by calling
debug_ll_io_init() early.

Without this patch, you can reliably reproduce a hang when early
printk is enabled by adding flush_tlb_all() at the start of
exynos_init_io().  After this patch the hang goes away.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c
index 027c9e7f0d137acf36c0502168137ee32f81e9a7..f7e504b7874d05e01ff13f4dce35d98c9cbec80a 100644 (file)
--- a/arch/arm/mach-exynos/common.c
+++ b/arch/arm/mach-exynos/common.c
@@ -386,6 +386,8 @@ int __init exynos_fdt_map_chipid(unsigned long node, const char *uname,
 
 void __init exynos_init_io(struct map_desc *mach_desc, int size)
 {
+       debug_ll_io_init();
+
 #ifdef CONFIG_OF
        if (initial_boot_params)
                of_scan_flat_dt(exynos_fdt_map_chipid, NULL);