From f23020230e682a43cc4706cabb041bba469df2d6 Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Wed, 5 Oct 2016 18:18:14 +0100 Subject: [PATCH] MIPS: Sanitise coherentio semantics The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle --- arch/mips/alchemy/common/setup.c | 6 +++--- arch/mips/include/asm/dma-coherence.h | 12 +++++++++--- arch/mips/include/asm/mach-generic/dma-coherence.h | 10 +++++++++- arch/mips/mm/c-r4k.c | 3 ++- arch/mips/mm/dma-default.c | 7 ++++--- arch/mips/mti-malta/malta-setup.c | 4 ++-- arch/mips/pci/pci-alchemy.c | 3 ++- 7 files changed, 31 insertions(+), 14 deletions(-) diff --git a/arch/mips/alchemy/common/setup.c b/arch/mips/alchemy/common/setup.c index 2902138b3e0f..7faaa6d593a7 100644 --- a/arch/mips/alchemy/common/setup.c +++ b/arch/mips/alchemy/common/setup.c @@ -48,17 +48,17 @@ void __init plat_mem_setup(void) clear_c0_config(1 << 19); /* Clear Config[OD] */ hw_coherentio = 0; - coherentio = 1; + coherentio = IO_COHERENCE_ENABLED; switch (alchemy_get_cputype()) { case ALCHEMY_CPU_AU1000: case ALCHEMY_CPU_AU1500: case ALCHEMY_CPU_AU1100: - coherentio = 0; + coherentio = IO_COHERENCE_DISABLED; break; case ALCHEMY_CPU_AU1200: /* Au1200 AB USB does not support coherent memory */ if (0 == (read_c0_prid() & PRID_REV_MASK)) - coherentio = 0; + coherentio = IO_COHERENCE_DISABLED; break; } diff --git a/arch/mips/include/asm/dma-coherence.h b/arch/mips/include/asm/dma-coherence.h index bc5e85d579e6..4fbce79fb57f 100644 --- a/arch/mips/include/asm/dma-coherence.h +++ b/arch/mips/include/asm/dma-coherence.h @@ -9,14 +9,20 @@ #ifndef __ASM_DMA_COHERENCE_H #define __ASM_DMA_COHERENCE_H +enum coherent_io_user_state { + IO_COHERENCE_DEFAULT, + IO_COHERENCE_ENABLED, + IO_COHERENCE_DISABLED, +}; + #ifdef CONFIG_DMA_MAYBE_COHERENT -extern int coherentio; +extern enum coherent_io_user_state coherentio; extern int hw_coherentio; #else #ifdef CONFIG_DMA_COHERENT -#define coherentio 1 +#define coherentio IO_COHERENCE_ENABLED #else -#define coherentio 0 +#define coherentio IO_COHERENCE_DISABLED #endif #define hw_coherentio 0 #endif /* CONFIG_DMA_MAYBE_COHERENT */ diff --git a/arch/mips/include/asm/mach-generic/dma-coherence.h b/arch/mips/include/asm/mach-generic/dma-coherence.h index 0f8a354fd468..8484f82fc794 100644 --- a/arch/mips/include/asm/mach-generic/dma-coherence.h +++ b/arch/mips/include/asm/mach-generic/dma-coherence.h @@ -49,7 +49,15 @@ static inline int plat_dma_supported(struct device *dev, u64 mask) static inline int plat_device_is_coherent(struct device *dev) { - return coherentio; + switch (coherentio) { + default: + case IO_COHERENCE_DEFAULT: + return hw_coherentio; + case IO_COHERENCE_ENABLED: + return 1; + case IO_COHERENCE_DISABLED: + return 0; + } } #ifndef plat_post_dma_flush diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index 1fc11184e999..78ac033a0f07 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -1935,7 +1935,8 @@ void r4k_cache_init(void) __local_flush_icache_user_range = local_r4k_flush_icache_user_range; #if defined(CONFIG_DMA_NONCOHERENT) || defined(CONFIG_DMA_MAYBE_COHERENT) - if (coherentio) { + if ((coherentio == IO_COHERENCE_ENABLED) || + ((coherentio == IO_COHERENCE_DEFAULT) && hw_coherentio)) { _dma_cache_wback_inv = (void *)cache_noop; _dma_cache_wback = (void *)cache_noop; _dma_cache_inv = (void *)cache_noop; diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c index 755259c54976..8b86c6168239 100644 --- a/arch/mips/mm/dma-default.c +++ b/arch/mips/mm/dma-default.c @@ -25,13 +25,14 @@ #include #ifdef CONFIG_DMA_MAYBE_COHERENT -int coherentio = 0; /* User defined DMA coherency from command line. */ +/* User defined DMA coherency from command line. */ +enum coherent_io_user_state coherentio = IO_COHERENCE_DEFAULT; EXPORT_SYMBOL_GPL(coherentio); int hw_coherentio = 0; /* Actual hardware supported DMA coherency setting. */ static int __init setcoherentio(char *str) { - coherentio = 1; + coherentio = IO_COHERENCE_ENABLED; pr_info("Hardware DMA cache coherency (command line)\n"); return 0; } @@ -39,7 +40,7 @@ early_param("coherentio", setcoherentio); static int __init setnocoherentio(char *str) { - coherentio = 0; + coherentio = IO_COHERENCE_DISABLED; pr_info("Software DMA cache coherency (command line)\n"); return 0; } diff --git a/arch/mips/mti-malta/malta-setup.c b/arch/mips/mti-malta/malta-setup.c index 7e7364b0501e..f1b6074828b1 100644 --- a/arch/mips/mti-malta/malta-setup.c +++ b/arch/mips/mti-malta/malta-setup.c @@ -154,12 +154,12 @@ static void __init plat_setup_iocoherency(void) * coherency instead. */ if (plat_enable_iocoherency()) { - if (coherentio == 0) + if (coherentio == IO_COHERENCE_DISABLED) pr_info("Hardware DMA cache coherency disabled\n"); else pr_info("Hardware DMA cache coherency enabled\n"); } else { - if (coherentio == 1) + if (coherentio == IO_COHERENCE_ENABLED) pr_info("Hardware DMA cache coherency unsupported, but enabled from command line!\n"); else pr_info("Software DMA cache coherency enabled\n"); diff --git a/arch/mips/pci/pci-alchemy.c b/arch/mips/pci/pci-alchemy.c index c8994c156e2d..e99ca7702d8a 100644 --- a/arch/mips/pci/pci-alchemy.c +++ b/arch/mips/pci/pci-alchemy.c @@ -429,7 +429,8 @@ static int alchemy_pci_probe(struct platform_device *pdev) /* Au1500 revisions older than AD have borked coherent PCI */ if ((alchemy_get_cputype() == ALCHEMY_CPU_AU1500) && - (read_c0_prid() < 0x01030202) && !coherentio) { + (read_c0_prid() < 0x01030202) && + (coherentio == IO_COHERENCE_DISABLED)) { val = __raw_readl(ctx->regs + PCI_REG_CONFIG); val |= PCI_CONFIG_NC; __raw_writel(val, ctx->regs + PCI_REG_CONFIG); -- 2.20.1