From 1c00f0161f5e5bf1a441ea834c923f4102456489 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Tue, 22 Mar 2011 16:34:59 -0700 Subject: x86: allow CONFIG_ISA_DMA_API to be disabled Not all 64-bit systems require ISA-style DMA, so allow it to be configurable. x86 utilizes the generic ISA DMA allocator from kernel/dma.c, so require it only when CONFIG_ISA_DMA_API is enabled. Disabling CONFIG_ISA_DMA_API is dependent on x86_64 since those machines do not have ISA slots and benefit the most from disabling the option (and on CONFIG_EXPERT as required by H. Peter Anvin). When disabled, this also avoids declaring claim_dma_lock(), release_dma_lock(), request_dma(), and free_dma() since those interfaces will no longer be provided. Signed-off-by: David Rientjes Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Thomas Gleixner Cc: Bjorn Helgaas Cc: Russell King Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/Kconfig | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 720206f46d04..d57ddd7573cc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -123,7 +123,7 @@ config NEED_SG_DMA_LENGTH def_bool y config GENERIC_ISA_DMA - def_bool y + def_bool ISA_DMA_API config GENERIC_IOMAP def_bool y @@ -2002,9 +2002,13 @@ source "drivers/pci/pcie/Kconfig" source "drivers/pci/Kconfig" -# x86_64 have no ISA slots, but do have ISA-style DMA. +# x86_64 have no ISA slots, but can have ISA-style DMA. config ISA_DMA_API - def_bool y + bool "ISA-style DMA support" if (X86_64 && EXPERT) + default y + help + Enables ISA-style DMA support for devices requiring such controllers. + If unsure, say Y. if X86_32 -- cgit v1.2.3