Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932323Ab3FEU5G (ORCPT ); Wed, 5 Jun 2013 16:57:06 -0400 Received: from mail-qc0-f202.google.com ([209.85.216.202]:41045 "EHLO mail-qc0-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932194Ab3FEU5A (ORCPT ); Wed, 5 Jun 2013 16:57:00 -0400 From: Doug Anderson To: Kukjin Kim , Olof Johansson Cc: Thomas Abraham , Simon Glass , linux-samsung-soc@vger.kernel.org, Tomasz Figa , Russell King , Ben Dooks , Doug Anderson , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.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 Message-Id: <1370465793-7997-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 1.8.3 In-Reply-To: <1370397539-21653-1-git-send-email-dianders@chromium.org> References: <1370397539-21653-1-git-send-email-dianders@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1430 Lines: 40 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 --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/