From: David S. Miller Date: Thu, 2 Jun 2005 19:55:50 +0000 (-0700) Subject: [PATCH] PCI: DMA bursting advice X-Git-Tag: v2.6.13-rc1~39^2~8 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e24c2d963a604d9eaa560c90371fa387d3eec8f1;p=linux-2.6 [PATCH] PCI: DMA bursting advice After seeing, at best, "guesses" as to the following kind of information in several drivers, I decided that we really need a way for platforms to specifically give advice in this area for what works best with their PCI controller implementation. Basically, this new interface gives DMA bursting advice on PCI. There are three forms of the advice: 1) Burst as much as possible, it is not necessary to end bursts on some particular boundary for best performance. 2) Burst on some byte count multiple. A DMA burst to some multiple of number of bytes may be done, but it is important to end the burst on an exact multiple for best performance. The best example of this I am aware of are the PPC64 PCI controllers, where if you end a burst mid-cacheline then chip has to refetch the data and the IOMMU translations which hurts performance a lot. 3) Burst on a single byte count multiple. Bursts shall end exactly on the next multiple boundary for best performance. Sparc64 and Alpha's PCI controllers operate this way. They disconnect any device which tries to burst across a cacheline boundary. Actually, newer sparc64 PCI controllers do not have this behavior. That is why the "pdev" is passed into the interface, so I can add code later to check which PCI controller the system is using and give advice accordingly. Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/asm-alpha/pci.h b/include/asm-alpha/pci.h index 0c7b57bc04..6c71dc1ad4 100644 --- a/include/asm-alpha/pci.h +++ b/include/asm-alpha/pci.h @@ -223,6 +223,23 @@ pci_dac_dma_sync_single_for_device(struct pci_dev *pdev, dma64_addr_t dma_addr, /* Nothing to do. */ } +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + unsigned long cacheline_size; + u8 byte; + + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &byte); + if (byte == 0) + cacheline_size = 1024; + else + cacheline_size = (int) byte * 4; + + *strat = PCI_DMA_BURST_BOUNDARY; + *strategy_parameter = cacheline_size; +} + /* TODO: integrate with include/asm-generic/pci.h ? */ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) { diff --git a/include/asm-arm/pci.h b/include/asm-arm/pci.h index 40ffaefbeb..bc2ec425ac 100644 --- a/include/asm-arm/pci.h +++ b/include/asm-arm/pci.h @@ -42,6 +42,14 @@ static inline void pcibios_penalize_isa_irq(int irq) #define pci_unmap_len(PTR, LEN_NAME) ((PTR)->LEN_NAME) #define pci_unmap_len_set(PTR, LEN_NAME, VAL) (((PTR)->LEN_NAME) = (VAL)) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + #define HAVE_PCI_MMAP extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); diff --git a/include/asm-frv/pci.h b/include/asm-frv/pci.h index a6a469231f..1342724066 100644 --- a/include/asm-frv/pci.h +++ b/include/asm-frv/pci.h @@ -57,6 +57,14 @@ extern void pci_free_consistent(struct pci_dev *hwdev, size_t size, */ #define PCI_DMA_BUS_IS_PHYS (1) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + /* * These are pretty much arbitary with the CoMEM implementation. * We have the whole address space to ourselves. diff --git a/include/asm-i386/pci.h b/include/asm-i386/pci.h index fb749b85a7..bf07b3af85 100644 --- a/include/asm-i386/pci.h +++ b/include/asm-i386/pci.h @@ -99,6 +99,14 @@ static inline void pcibios_add_platform_entries(struct pci_dev *dev) { } +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + #endif /* __KERNEL__ */ /* implement the pci_ DMA API in terms of the generic device dma_ one */ diff --git a/include/asm-ia64/pci.h b/include/asm-ia64/pci.h index a8314ee4e7..c9f1ab4e47 100644 --- a/include/asm-ia64/pci.h +++ b/include/asm-ia64/pci.h @@ -82,6 +82,23 @@ extern int pcibios_prep_mwi (struct pci_dev *); #define sg_dma_len(sg) ((sg)->dma_length) #define sg_dma_address(sg) ((sg)->dma_address) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + unsigned long cacheline_size; + u8 byte; + + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &byte); + if (byte == 0) + cacheline_size = 1024; + else + cacheline_size = (int) byte * 4; + + *strat = PCI_DMA_BURST_MULTIPLE; + *strategy_parameter = cacheline_size; +} + #define HAVE_PCI_MMAP extern int pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); diff --git a/include/asm-mips/pci.h b/include/asm-mips/pci.h index c9c576b485..20b93bfa45 100644 --- a/include/asm-mips/pci.h +++ b/include/asm-mips/pci.h @@ -130,6 +130,14 @@ extern void pci_dac_dma_sync_single_for_cpu(struct pci_dev *pdev, extern void pci_dac_dma_sync_single_for_device(struct pci_dev *pdev, dma64_addr_t dma_addr, size_t len, int direction); +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + extern void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region, struct resource *res); diff --git a/include/asm-parisc/pci.h b/include/asm-parisc/pci.h index 0763c2982f..f9f5bf9011 100644 --- a/include/asm-parisc/pci.h +++ b/include/asm-parisc/pci.h @@ -230,6 +230,23 @@ extern inline void pcibios_register_hba(struct pci_hba_data *x) /* export the pci_ DMA API in terms of the dma_ one */ #include +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + unsigned long cacheline_size; + u8 byte; + + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &byte); + if (byte == 0) + cacheline_size = 1024; + else + cacheline_size = (int) byte * 4; + + *strat = PCI_DMA_BURST_MULTIPLE; + *strategy_parameter = cacheline_size; +} + extern void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region, struct resource *res); diff --git a/include/asm-ppc/pci.h b/include/asm-ppc/pci.h index 002e7b3057..669e9de7a5 100644 --- a/include/asm-ppc/pci.h +++ b/include/asm-ppc/pci.h @@ -69,6 +69,14 @@ extern unsigned long pci_bus_to_phys(unsigned int ba, int busnr); #define pci_unmap_len(PTR, LEN_NAME) (0) #define pci_unmap_len_set(PTR, LEN_NAME, VAL) do { } while (0) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + /* * At present there are very few 32-bit PPC machines that can have * memory above the 4GB point, and we don't support that. diff --git a/include/asm-ppc64/pci.h b/include/asm-ppc64/pci.h index 411bf5dee3..20beb10c09 100644 --- a/include/asm-ppc64/pci.h +++ b/include/asm-ppc64/pci.h @@ -78,6 +78,23 @@ static inline int pci_dac_dma_supported(struct pci_dev *hwdev,u64 mask) return 0; } +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + unsigned long cacheline_size; + u8 byte; + + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &byte); + if (byte == 0) + cacheline_size = 1024; + else + cacheline_size = (int) byte * 4; + + *strat = PCI_DMA_BURST_MULTIPLE; + *strategy_parameter = cacheline_size; +} + extern int pci_domain_nr(struct pci_bus *bus); /* Decide whether to display the domain number in /proc */ diff --git a/include/asm-sh/pci.h b/include/asm-sh/pci.h index 9c3b63d010..7237bc6a72 100644 --- a/include/asm-sh/pci.h +++ b/include/asm-sh/pci.h @@ -96,6 +96,14 @@ static inline void pcibios_penalize_isa_irq(int irq) #define sg_dma_address(sg) (virt_to_bus((sg)->dma_address)) #define sg_dma_len(sg) ((sg)->length) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + /* Board-specific fixup routines. */ extern void pcibios_fixup(void); extern void pcibios_fixup_irqs(void); diff --git a/include/asm-sh64/pci.h b/include/asm-sh64/pci.h index 8cc14e1397..0ac15ab01c 100644 --- a/include/asm-sh64/pci.h +++ b/include/asm-sh64/pci.h @@ -86,6 +86,14 @@ static inline void pcibios_penalize_isa_irq(int irq) #define sg_dma_address(sg) ((sg)->dma_address) #define sg_dma_len(sg) ((sg)->length) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + /* Board-specific fixup routines. */ extern void pcibios_fixup(void); extern void pcibios_fixup_irqs(void); diff --git a/include/asm-sparc/pci.h b/include/asm-sparc/pci.h index d200a25a73..2fd65db95e 100644 --- a/include/asm-sparc/pci.h +++ b/include/asm-sparc/pci.h @@ -144,6 +144,14 @@ extern inline int pci_dma_supported(struct pci_dev *hwdev, u64 mask) #define pci_dac_dma_supported(dev, mask) (0) +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + static inline void pcibios_add_platform_entries(struct pci_dev *dev) { } diff --git a/include/asm-sparc64/pci.h b/include/asm-sparc64/pci.h index 2a0c85cd1c..402667300d 100644 --- a/include/asm-sparc64/pci.h +++ b/include/asm-sparc64/pci.h @@ -220,6 +220,23 @@ static inline int pci_dma_mapping_error(dma_addr_t dma_addr) return (dma_addr == PCI_DMA_ERROR_CODE); } +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + unsigned long cacheline_size; + u8 byte; + + pci_read_config_byte(pdev, PCI_CACHE_LINE_SIZE, &byte); + if (byte == 0) + cacheline_size = 1024; + else + cacheline_size = (int) byte * 4; + + *strat = PCI_DMA_BURST_BOUNDARY; + *strategy_parameter = cacheline_size; +} + /* Return the index of the PCI controller for device PDEV. */ extern int pci_domain_nr(struct pci_bus *bus); diff --git a/include/asm-v850/pci.h b/include/asm-v850/pci.h index e41941447b..d26eb8d673 100644 --- a/include/asm-v850/pci.h +++ b/include/asm-v850/pci.h @@ -81,6 +81,14 @@ extern void pci_free_consistent (struct pci_dev *pdev, size_t size, void *cpu_addr, dma_addr_t dma_addr); +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + static inline void pcibios_add_platform_entries(struct pci_dev *dev) { } diff --git a/include/asm-x86_64/pci.h b/include/asm-x86_64/pci.h index 8712520ca4..8461d6af10 100644 --- a/include/asm-x86_64/pci.h +++ b/include/asm-x86_64/pci.h @@ -123,6 +123,14 @@ pci_dac_dma_sync_single_for_device(struct pci_dev *pdev, dma64_addr_t dma_addr, flush_write_buffers(); } +static inline void pci_dma_burst_advice(struct pci_dev *pdev, + enum pci_dma_burst_strategy *strat, + unsigned long *strategy_parameter) +{ + *strat = PCI_DMA_BURST_INFINITY; + *strategy_parameter = ~0UL; +} + #define HAVE_PCI_MMAP extern int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma, enum pci_mmap_state mmap_state, int write_combine); diff --git a/include/linux/pci.h b/include/linux/pci.h index cfa1455848..9ce4f1be09 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -874,6 +874,15 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max, int pass #define pci_pool_alloc(pool, flags, handle) dma_pool_alloc(pool, flags, handle) #define pci_pool_free(pool, vaddr, addr) dma_pool_free(pool, vaddr, addr) +enum pci_dma_burst_strategy { + PCI_DMA_BURST_INFINITY, /* make bursts as large as possible, + strategy_parameter is N/A */ + PCI_DMA_BURST_BOUNDARY, /* disconnect at every strategy_parameter + byte boundaries */ + PCI_DMA_BURST_MULTIPLE, /* disconnect at some multiple of + strategy_parameter byte boundaries */ +}; + #if defined(CONFIG_ISA) || defined(CONFIG_EISA) extern struct pci_dev *isa_bridge; #endif