cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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fixup-sb1250.c (2729B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *	Copyright (C) 2004, 2006  MIPS Technologies, Inc.  All rights reserved.
      4 *	    Author:	Maciej W. Rozycki <macro@mips.com>
      5 *	Copyright (C) 2018  Maciej W. Rozycki
      6 */
      7
      8#include <linux/dma-mapping.h>
      9#include <linux/pci.h>
     10
     11/*
     12 * Set the BCM1250, etc. PCI host bridge's TRDY timeout
     13 * to the finite max.
     14 */
     15static void quirk_sb1250_pci(struct pci_dev *dev)
     16{
     17	pci_write_config_byte(dev, 0x40, 0xff);
     18}
     19DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
     20			quirk_sb1250_pci);
     21
     22/*
     23 * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit
     24 * bus, so we set the bus's DMA limit accordingly.  However the HT link
     25 * down the artificial PCI-HT bridge supports 40-bit addressing and the
     26 * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus
     27 * width, so we record the PCI-HT bridge's secondary and subordinate bus
     28 * numbers and do not set the limit for devices present in the inclusive
     29 * range of those.
     30 */
     31struct sb1250_bus_dma_limit_exclude {
     32	bool set;
     33	unsigned char start;
     34	unsigned char end;
     35};
     36
     37static int sb1250_bus_dma_limit(struct pci_dev *dev, void *data)
     38{
     39	struct sb1250_bus_dma_limit_exclude *exclude = data;
     40	bool exclude_this;
     41	bool ht_bridge;
     42
     43	exclude_this = exclude->set && (dev->bus->number >= exclude->start &&
     44					dev->bus->number <= exclude->end);
     45	ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE &&
     46				      dev->device == PCI_DEVICE_ID_BCM1250_HT);
     47
     48	if (exclude_this) {
     49		dev_dbg(&dev->dev, "not disabling DAC for device");
     50	} else if (ht_bridge) {
     51		exclude->start = dev->subordinate->number;
     52		exclude->end = pci_bus_max_busnr(dev->subordinate);
     53		exclude->set = true;
     54		dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]",
     55			exclude->start, exclude->end);
     56	} else {
     57		dev_dbg(&dev->dev, "disabling DAC for device");
     58		dev->dev.bus_dma_limit = DMA_BIT_MASK(32);
     59	}
     60
     61	return 0;
     62}
     63
     64static void quirk_sb1250_pci_dac(struct pci_dev *dev)
     65{
     66	struct sb1250_bus_dma_limit_exclude exclude = { .set = false };
     67
     68	pci_walk_bus(dev->bus, sb1250_bus_dma_limit, &exclude);
     69}
     70DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI,
     71			quirk_sb1250_pci_dac);
     72
     73/*
     74 * The BCM1250, etc. PCI/HT bridge reports as a host bridge.
     75 */
     76static void quirk_sb1250_ht(struct pci_dev *dev)
     77{
     78	dev->class = PCI_CLASS_BRIDGE_PCI_NORMAL;
     79}
     80DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,
     81			quirk_sb1250_ht);
     82
     83/*
     84 * Set the SP1011 HT/PCI bridge's TRDY timeout to the finite max.
     85 */
     86static void quirk_sp1011(struct pci_dev *dev)
     87{
     88	pci_write_config_byte(dev, 0x64, 0xff);
     89}
     90DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
     91			quirk_sp1011);