From: dianders@chromium.org (Doug Anderson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: exynos: add debug_ll_io_init() call in exynos_init_io()
Date: Wed, 5 Jun 2013 13:56:33 -0700 [thread overview]
Message-ID: <1370465793-7997-1-git-send-email-dianders@chromium.org> (raw)
In-Reply-To: <1370397539-21653-1-git-send-email-dianders@chromium.org>
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>
---
Changes in v2:
- Use debug_ll_io_init() instead of reordering printks and adding
warnings. Thanks Olof!
arch/arm/mach-exynos/common.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/mach-exynos/common.c b/arch/arm/mach-exynos/common.c
index 027c9e7..f7e504b 100644
--- 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);
--
1.8.3
next prev parent reply other threads:[~2013-06-05 20:56 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-05 1:58 [PATCH] ARM: samsung: avoid racy early printk at bootup Doug Anderson
2013-06-05 3:15 ` Olof Johansson
2013-06-05 20:56 ` Doug Anderson
2013-06-05 20:56 ` Doug Anderson [this message]
2013-06-05 21:12 ` [PATCH v2] ARM: exynos: add debug_ll_io_init() call in exynos_init_io() Olof Johansson
2013-06-05 23:32 ` Kukjin Kim
2013-06-08 1:12 ` Olof Johansson
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