Messages in this thread | | | Date | Fri, 12 Sep 2014 21:35:29 +0300 | From | Sergei Shtylyov <> | Subject | Re: [PATCH V2] MIPS: bugfix of coherentio variable default setup |
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Hello.
On 9/8/2014 10:10 PM, Leonid Yegoshin wrote:
> Patch commit b6d92b4a6bdb880b39789c677b952c53a437028d
Just commit.
> MIPS: Add option to disable software I/O coherency.
It's enough to just cite the summary in parens after SHA1 ID.
> Some MIPS controllers have hardware I/O coherency. This patch > detects those and turns off software coherency. A new kernel > command line option also allows the user to manually turn > software coherency on or off.
> in fact enforces L2 cache flushes even on systems with IOCU. > The default value of coherentio is 0 and is not changed even with IOCU. > It is a serious performance problem because it destroys all IOCU performance > advantages.
> It is fixed by setting coherentio to tri-state with default value as (-1) and > setup a final value during platform coherency setup.
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> > --- > V2: Missed signature added > --- > arch/mips/include/asm/mach-generic/dma-coherence.h | 7 ++++++- > arch/mips/mm/c-r4k.c | 2 +- > arch/mips/mm/dma-default.c | 2 +- > arch/mips/mti-malta/malta-setup.c | 8 ++++++-- > arch/mips/pci/pci-alchemy.c | 2 +- > 5 files changed, 15 insertions(+), 6 deletions(-) > > diff --git a/arch/mips/include/asm/mach-generic/dma-coherence.h b/arch/mips/include/asm/mach-generic/dma-coherence.h > index 7629c35..b4563df 100644 > --- a/arch/mips/include/asm/mach-generic/dma-coherence.h > +++ b/arch/mips/include/asm/mach-generic/dma-coherence.h > @@ -49,7 +49,12 @@ static inline int plat_dma_supported(struct device *dev, u64 mask) > > static inline int plat_device_is_coherent(struct device *dev) > { > - return coherentio; > +#ifdef CONFIG_DMA_COHERENT > + return 1; > +#else > + return (coherentio > 0);
*return* never needs parens around the value.
> +#endif > + > } > > #ifdef CONFIG_SWIOTLB > diff --git a/arch/mips/mti-malta/malta-setup.c b/arch/mips/mti-malta/malta-setup.c > index db7c9e5..48039fd 100644 > --- a/arch/mips/mti-malta/malta-setup.c > +++ b/arch/mips/mti-malta/malta-setup.c > @@ -147,13 +147,17 @@ static void __init plat_setup_iocoherency(void) > if (plat_enable_iocoherency()) { > if (coherentio == 0) > pr_info("Hardware DMA cache coherency disabled\n"); > - else > + else { > + coherentio = 1;
You now need the parens around another arm of the *if* statement too. Such is the kernel style. :-)
> pr_info("Hardware DMA cache coherency enabled\n"); > + } > } else { > if (coherentio == 1) > pr_info("Hardware DMA cache coherency unsupported, but enabled from command line!\n"); > - else > + else { > + coherentio = 0;
Likewise.
> pr_info("Software DMA cache coherency enabled\n"); > + } > } > #else > if (!plat_enable_iocoherency())
WBR, Sergei
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