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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/mips/pci/fixup-sb1250.c
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// SPDX-License-Identifier: GPL-2.0-or-later

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/*

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 *	Copyright (C) 2004, 2006  MIPS Technologies, Inc.  All rights reserved.

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 *	    Author:	Maciej W. Rozycki <[email protected]>

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 *	Copyright (C) 2018  Maciej W. Rozycki

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 */

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#include <linux/dma-mapping.h>

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#include <linux/pci.h>

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/*

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 * Set the BCM1250, etc. PCI host bridge's TRDY timeout

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 * to the finite max.

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 */

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static void quirk_sb1250_pci(struct pci_dev *dev)

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{

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	pci_write_config_byte(dev, 0x40, 0xff);

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}

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DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,

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			quirk_sb1250_pci);

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/*

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 * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit

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 * bus, so we set the bus's DMA limit accordingly.  However the HT link

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 * down the artificial PCI-HT bridge supports 40-bit addressing and the

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 * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus

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 * width, so we record the PCI-HT bridge's secondary and subordinate bus

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 * numbers and do not set the limit for devices present in the inclusive

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 * range of those.

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 */

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struct sb1250_bus_dma_limit_exclude {

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	bool set;

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	unsigned char start;

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	unsigned char end;

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};

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static int sb1250_bus_dma_limit(struct pci_dev *dev, void *data)

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{

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	struct sb1250_bus_dma_limit_exclude *exclude = data;

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	bool exclude_this;

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	bool ht_bridge;

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	exclude_this = exclude->set && (dev->bus->number >= exclude->start &&

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					dev->bus->number <= exclude->end);

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	ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE &&

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				      dev->device == PCI_DEVICE_ID_BCM1250_HT);

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	if (exclude_this) {

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		dev_dbg(&dev->dev, "not disabling DAC for device");

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	} else if (ht_bridge) {

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		exclude->start = dev->subordinate->number;

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		exclude->end = pci_bus_max_busnr(dev->subordinate);

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		exclude->set = true;

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		dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]",

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			exclude->start, exclude->end);

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	} else {

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		dev_dbg(&dev->dev, "disabling DAC for device");

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		dev->dev.bus_dma_limit = DMA_BIT_MASK(32);

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	}

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	return 0;

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}

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static void quirk_sb1250_pci_dac(struct pci_dev *dev)

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{

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	struct sb1250_bus_dma_limit_exclude exclude = { .set = false };

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	pci_walk_bus(dev->bus, sb1250_bus_dma_limit, &exclude);

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}

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DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,

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			quirk_sb1250_pci_dac);

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/*

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 * The BCM1250, etc. PCI/HT bridge reports as a host bridge.

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 */

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static void quirk_sb1250_ht(struct pci_dev *dev)

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{

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	dev->class = PCI_CLASS_BRIDGE_PCI_NORMAL;

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}

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DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,

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			quirk_sb1250_ht);

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/*

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 * Set the SP1011 HT/PCI bridge's TRDY timeout to the finite max.

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 */

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static void quirk_sp1011(struct pci_dev *dev)

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{

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	pci_write_config_byte(dev, 0x64, 0xff);

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}

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DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,

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			quirk_sp1011);

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