Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751428AbaFWFGI (ORCPT ); Mon, 23 Jun 2014 01:06:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5370 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751066AbaFWFGG (ORCPT ); Mon, 23 Jun 2014 01:06:06 -0400 From: Mark Salter To: Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Salter Subject: [PATCH] arm64: make CONFIG_ZONE_DMA user settable Date: Mon, 23 Jun 2014 01:05:24 -0400 Message-Id: <1403499924-11214-1-git-send-email-msalter@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 19e7640d1f (arm64: Replace ZONE_DMA32 with ZONE_DMA) moves support for 32-bit DMA addressing into ZONE_DMA and renames CONFIG_ZONE_DMA32 to CONFIG_ZONE_DMA. Commit 2d5a5612bc (arm64: Limit the CMA buffer to 32-bit if ZONE_DMA) forces the CMA buffer to be 32-bit addressable if CONFIG_ZONE_DMA is defined. These two patches pose a problem for platforms which have no 32-bit addressable DRAM. If CONFIG_ZONE_DMA is turned on for such platforms, CMA is unable to reserve a buffer for allocations. CONFIG_ZONE_DMA is not user settable however, so there is no way to turn it off without editing arch/arm64/Kconfig. Even if one edits Kconfig to turn off CONFIG_ZONE_DMA, the kernel fails to build with such a config: arch/arm64/mm/init.c: In function ‘zone_sizes_init’: arch/arm64/mm/init.c:76:13: error: ‘ZONE_DMA’ undeclared (first use in this function) zone_size[ZONE_DMA] = max_dma - min; ^ This patch makes CONFIG_ZONE_DMA user settable and fixes the kernel build when it is turned off. Signed-off-by: Mark Salter --- arch/arm64/Kconfig | 11 ++++++++--- arch/arm64/mm/init.c | 8 ++++++-- 2 files changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index c8b1d0b..f669597 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -99,9 +99,6 @@ config GENERIC_CSUM config GENERIC_CALIBRATE_DELAY def_bool y -config ZONE_DMA - def_bool y - config ARCH_DMA_ADDR_T_64BIT def_bool y @@ -211,6 +208,14 @@ config HOTPLUG_CPU Say Y here to experiment with turning CPUs off and on. CPUs can be controlled through /sys/devices/system/cpu. +config ZONE_DMA + bool "32-bit DMA memory allocation" + def_bool y + help + 32-bit DMA memory allocation supports devices limited to 32-bit + DMA addressing to allocate within the first 4GiB of address space. + Disable if no such devices will be used. + source kernel/Kconfig.preempt config HZ diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index f43db8a..c5415e2 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -69,12 +69,14 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) memset(zone_size, 0, sizeof(zone_size)); /* 4GB maximum for 32-bit only capable devices */ - if (IS_ENABLED(CONFIG_ZONE_DMA)) { +#ifdef CONFIG_ZONE_DMA + { unsigned long max_dma_phys = (unsigned long)(dma_to_phys(NULL, DMA_BIT_MASK(32)) + 1); max_dma = max(min, min(max, max_dma_phys >> PAGE_SHIFT)); zone_size[ZONE_DMA] = max_dma - min; } +#endif zone_size[ZONE_NORMAL] = max - max_dma; memcpy(zhole_size, zone_size, sizeof(zhole_size)); @@ -86,10 +88,12 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) if (start >= max) continue; - if (IS_ENABLED(CONFIG_ZONE_DMA) && start < max_dma) { +#ifdef CONFIG_ZONE_DMA + if (start < max_dma) { unsigned long dma_end = min(end, max_dma); zhole_size[ZONE_DMA] -= dma_end - start; } +#endif if (end > max_dma) { unsigned long normal_end = min(end, max); -- 1.8.3.1 -- 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/