e24c2d963a
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 <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
116 lines
3.3 KiB
C
116 lines
3.3 KiB
C
/* pci.h: FR-V specific PCI declarations
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*
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* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from include/asm-m68k/pci.h
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef ASM_PCI_H
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#define ASM_PCI_H
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#include <linux/config.h>
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#include <linux/mm.h>
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#include <asm/scatterlist.h>
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#include <asm-generic/pci-dma-compat.h>
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#include <asm-generic/pci.h>
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struct pci_dev;
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#define pcibios_assign_all_busses() 0
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static inline void pcibios_add_platform_entries(struct pci_dev *dev)
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{
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}
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extern void pcibios_set_master(struct pci_dev *dev);
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extern void pcibios_penalize_isa_irq(int irq);
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#ifdef CONFIG_MMU
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extern void *consistent_alloc(int gfp, size_t size, dma_addr_t *dma_handle);
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extern void consistent_free(void *vaddr);
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extern void consistent_sync(void *vaddr, size_t size, int direction);
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extern void consistent_sync_page(struct page *page, unsigned long offset,
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size_t size, int direction);
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#endif
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extern void *pci_alloc_consistent(struct pci_dev *hwdev, size_t size,
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dma_addr_t *dma_handle);
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extern void pci_free_consistent(struct pci_dev *hwdev, size_t size,
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void *vaddr, dma_addr_t dma_handle);
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/* This is always fine. */
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#define pci_dac_dma_supported(pci_dev, mask) (1)
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/* Return the index of the PCI controller for device PDEV. */
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#define pci_controller_num(PDEV) (0)
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/* The PCI address space does equal the physical memory
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* address space. The networking and block device layers use
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* this boolean for bounce buffer decisions.
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*/
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#define PCI_DMA_BUS_IS_PHYS (1)
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static inline void pci_dma_burst_advice(struct pci_dev *pdev,
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enum pci_dma_burst_strategy *strat,
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unsigned long *strategy_parameter)
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{
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*strat = PCI_DMA_BURST_INFINITY;
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*strategy_parameter = ~0UL;
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}
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/*
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* These are pretty much arbitary with the CoMEM implementation.
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* We have the whole address space to ourselves.
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*/
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#define PCIBIOS_MIN_IO 0x100
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#define PCIBIOS_MIN_MEM 0x00010000
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/* Make physical memory consistent for a single
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* streaming mode DMA translation after a transfer.
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*
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* If you perform a pci_map_single() but wish to interrogate the
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* buffer using the cpu, yet do not wish to teardown the PCI dma
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* mapping, you must call this function before doing so. At the
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* next point you give the PCI dma address back to the card, the
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* device again owns the buffer.
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*/
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static inline void pci_dma_sync_single(struct pci_dev *hwdev,
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dma_addr_t dma_handle,
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size_t size, int direction)
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{
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if (direction == PCI_DMA_NONE)
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BUG();
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frv_cache_wback_inv((unsigned long)bus_to_virt(dma_handle),
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(unsigned long)bus_to_virt(dma_handle) + size);
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}
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/* Make physical memory consistent for a set of streaming
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* mode DMA translations after a transfer.
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*
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* The same as pci_dma_sync_single but for a scatter-gather list,
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* same rules and usage.
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*/
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static inline void pci_dma_sync_sg(struct pci_dev *hwdev,
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struct scatterlist *sg,
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int nelems, int direction)
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{
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int i;
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if (direction == PCI_DMA_NONE)
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BUG();
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for (i = 0; i < nelems; i++)
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frv_cache_wback_inv(sg_dma_address(&sg[i]),
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sg_dma_address(&sg[i])+sg_dma_len(&sg[i]));
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}
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#endif
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