diff options
| author | David Rientjes <rientjes@google.com> | 2011-03-22 16:34:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-22 17:44:16 -0700 |
| commit | 1c00f0161f5e5bf1a441ea834c923f4102456489 (patch) | |
| tree | 8d8bebdfe155d5afd60b412e5985691276b38baf | |
| parent | 8df3bd9e18cdc3539edea550be34605a240e15d4 (diff) | |
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 <rientjes@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/Kconfig | 10 | ||||
| -rw-r--r-- | arch/x86/include/asm/dma.h | 6 |
2 files changed, 12 insertions, 4 deletions
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 diff --git a/arch/x86/include/asm/dma.h b/arch/x86/include/asm/dma.h index ca1098a7e580..97b6d8114a43 100644 --- a/arch/x86/include/asm/dma.h +++ b/arch/x86/include/asm/dma.h @@ -151,6 +151,7 @@ #define DMA_AUTOINIT 0x10 +#ifdef CONFIG_ISA_DMA_API extern spinlock_t dma_spin_lock; static inline unsigned long claim_dma_lock(void) @@ -164,6 +165,7 @@ static inline void release_dma_lock(unsigned long flags) { spin_unlock_irqrestore(&dma_spin_lock, flags); } +#endif /* CONFIG_ISA_DMA_API */ /* enable/disable a specific DMA channel */ static inline void enable_dma(unsigned int dmanr) @@ -303,9 +305,11 @@ static inline int get_dma_residue(unsigned int dmanr) } -/* These are in kernel/dma.c: */ +/* These are in kernel/dma.c because x86 uses CONFIG_GENERIC_ISA_DMA */ +#ifdef CONFIG_ISA_DMA_API extern int request_dma(unsigned int dmanr, const char *device_id); extern void free_dma(unsigned int dmanr); +#endif /* From PCI */ |