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| 1 | +// SPDX-License-Identifier: GPL-2.0-or-later |
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| 1 | 2 | /* |
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| 2 | 3 | * Copyright (C) 2004, 2006 MIPS Technologies, Inc. All rights reserved. |
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| 3 | 4 | * Author: Maciej W. Rozycki <macro@mips.com> |
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| 4 | | - * |
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| 5 | | - * This program is free software; you can redistribute it and/or |
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| 6 | | - * modify it under the terms of the GNU General Public License |
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| 7 | | - * as published by the Free Software Foundation; either version |
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| 8 | | - * 2 of the License, or (at your option) any later version. |
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| 5 | + * Copyright (C) 2018 Maciej W. Rozycki |
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| 9 | 6 | */ |
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| 10 | 7 | |
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| 8 | +#include <linux/dma-mapping.h> |
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| 11 | 9 | #include <linux/pci.h> |
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| 12 | 10 | |
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| 13 | 11 | /* |
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| .. | .. |
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| 22 | 20 | quirk_sb1250_pci); |
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| 23 | 21 | |
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| 24 | 22 | /* |
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| 23 | + * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit |
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| 24 | + * bus, so we set the bus's DMA limit accordingly. However the HT link |
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| 25 | + * down the artificial PCI-HT bridge supports 40-bit addressing and the |
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| 26 | + * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus |
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| 27 | + * width, so we record the PCI-HT bridge's secondary and subordinate bus |
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| 28 | + * numbers and do not set the limit for devices present in the inclusive |
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| 29 | + * range of those. |
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| 30 | + */ |
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| 31 | +struct sb1250_bus_dma_limit_exclude { |
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| 32 | + bool set; |
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| 33 | + unsigned char start; |
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| 34 | + unsigned char end; |
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| 35 | +}; |
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| 36 | + |
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| 37 | +static int sb1250_bus_dma_limit(struct pci_dev *dev, void *data) |
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| 38 | +{ |
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| 39 | + struct sb1250_bus_dma_limit_exclude *exclude = data; |
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| 40 | + bool exclude_this; |
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| 41 | + bool ht_bridge; |
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| 42 | + |
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| 43 | + exclude_this = exclude->set && (dev->bus->number >= exclude->start && |
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| 44 | + dev->bus->number <= exclude->end); |
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| 45 | + ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE && |
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| 46 | + dev->device == PCI_DEVICE_ID_BCM1250_HT); |
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| 47 | + |
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| 48 | + if (exclude_this) { |
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| 49 | + dev_dbg(&dev->dev, "not disabling DAC for device"); |
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| 50 | + } else if (ht_bridge) { |
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| 51 | + exclude->start = dev->subordinate->number; |
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| 52 | + exclude->end = pci_bus_max_busnr(dev->subordinate); |
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| 53 | + exclude->set = true; |
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| 54 | + dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]", |
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| 55 | + exclude->start, exclude->end); |
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| 56 | + } else { |
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| 57 | + dev_dbg(&dev->dev, "disabling DAC for device"); |
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| 58 | + dev->dev.bus_dma_limit = DMA_BIT_MASK(32); |
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| 59 | + } |
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| 60 | + |
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| 61 | + return 0; |
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| 62 | +} |
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| 63 | + |
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| 64 | +static void quirk_sb1250_pci_dac(struct pci_dev *dev) |
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| 65 | +{ |
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| 66 | + struct sb1250_bus_dma_limit_exclude exclude = { .set = false }; |
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| 67 | + |
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| 68 | + pci_walk_bus(dev->bus, sb1250_bus_dma_limit, &exclude); |
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| 69 | +} |
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| 70 | +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI, |
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| 71 | + quirk_sb1250_pci_dac); |
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| 72 | + |
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| 73 | +/* |
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| 25 | 74 | * The BCM1250, etc. PCI/HT bridge reports as a host bridge. |
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| 26 | 75 | */ |
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| 27 | 76 | static void quirk_sb1250_ht(struct pci_dev *dev) |
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