From: rubisher <rubisher@scarlet.be>
To: linux-parisc@vger.kernel.org
Subject: dma_addr_t: which comment is correct?
Date: Sat, 22 Dec 2007 12:15:31 +0000 [thread overview]
Message-ID: <476CFFE3.3040102@scarlet.be> (raw)
Hello *,
Continuing my blind investigation on ccio-dma stuff, I read those 2 different comments:
in include/asm-parisc/scatterlist.h, scartterlist structure is defined like this:
struct scatterlist {
#ifdef CONFIG_DEBUG_SG
unsigned long sg_magic;
#endif
unsigned long page_link;
unsigned int offset;
unsigned int length;
/* an IOVA can be 64-bits on some PA-Risc platforms. */
dma_addr_t iova; /* I/O Virtual Address */
__u32 iova_length; /* bytes mapped */
};
in absolute the comment "an IOVA can be 64-bits on some PA-Risc platforms." seems ok.
but otoh, include/asm-parisc/types.h, defined dma_addr_t like this:
/* Dma addresses are 32-bits wide. */
typedef u32 dma_addr_t;
typedef u64 dma64_addr_t;
#endif /* __ASSEMBLY__ */
OK it's just a comment but imho there is interesting matter in x86:
typedef u64 dma64_addr_t;
#if defined(CONFIG_X86_64) || defined(CONFIG_HIGHMEM64G)
/* DMA addresses come in 32-bit and 64-bit flavours. */
typedef u64 dma_addr_t;
#else
typedef u32 dma_addr_t;
#endif
But I simply have no idea which "#if defined" would be the most relevant for parisc, any idea?
Cheers,
r.
next reply other threads:[~2007-12-22 12:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-22 12:15 rubisher [this message]
2007-12-23 9:39 ` dma_addr_t: which comment is correct? Grant Grundler
2007-12-23 22:50 ` rubisher
2007-12-24 8:51 ` Grant Grundler
2007-12-26 10:01 ` Thibaut VARENE
2007-12-26 17:31 ` iommu_fill_pdir() and its /* Horrible hack. ... */ reading rubisher
2007-12-28 8:27 ` Grant Grundler
2007-12-28 15:27 ` rubisher
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