diff options
Diffstat (limited to 'arch/mips/pci/fixup-sb1250.c')
| -rw-r--r-- | arch/mips/pci/fixup-sb1250.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/arch/mips/pci/fixup-sb1250.c b/arch/mips/pci/fixup-sb1250.c index 8feae9154baf..45266406b585 100644 --- a/arch/mips/pci/fixup-sb1250.c +++ b/arch/mips/pci/fixup-sb1250.c @@ -1,6 +1,7 @@ /* * Copyright (C) 2004, 2006 MIPS Technologies, Inc. All rights reserved. * Author: Maciej W. Rozycki <macro@mips.com> + * Copyright (C) 2018 Maciej W. Rozycki * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License @@ -8,6 +9,7 @@ * 2 of the License, or (at your option) any later version. */ +#include <linux/dma-mapping.h> #include <linux/pci.h> /* @@ -22,6 +24,57 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI, quirk_sb1250_pci); /* + * The BCM1250, etc. PCI host bridge does not support DAC on its 32-bit + * bus, so we set the bus's DMA mask accordingly. However the HT link + * down the artificial PCI-HT bridge supports 40-bit addressing and the + * SP1011 HT-PCI bridge downstream supports both DAC and a 64-bit bus + * width, so we record the PCI-HT bridge's secondary and subordinate bus + * numbers and do not set the mask for devices present in the inclusive + * range of those. + */ +struct sb1250_bus_dma_mask_exclude { + bool set; + unsigned char start; + unsigned char end; +}; + +static int sb1250_bus_dma_mask(struct pci_dev *dev, void *data) +{ + struct sb1250_bus_dma_mask_exclude *exclude = data; + bool exclude_this; + bool ht_bridge; + + exclude_this = exclude->set && (dev->bus->number >= exclude->start && + dev->bus->number <= exclude->end); + ht_bridge = !exclude->set && (dev->vendor == PCI_VENDOR_ID_SIBYTE && + dev->device == PCI_DEVICE_ID_BCM1250_HT); + + if (exclude_this) { + dev_dbg(&dev->dev, "not disabling DAC for device"); + } else if (ht_bridge) { + exclude->start = dev->subordinate->number; + exclude->end = pci_bus_max_busnr(dev->subordinate); + exclude->set = true; + dev_dbg(&dev->dev, "not disabling DAC for [bus %02x-%02x]", + exclude->start, exclude->end); + } else { + dev_dbg(&dev->dev, "disabling DAC for device"); + dev->dev.bus_dma_mask = DMA_BIT_MASK(32); + } + + return 0; +} + +static void quirk_sb1250_pci_dac(struct pci_dev *dev) +{ + struct sb1250_bus_dma_mask_exclude exclude = { .set = false }; + + pci_walk_bus(dev->bus, sb1250_bus_dma_mask, &exclude); +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_PCI, + quirk_sb1250_pci_dac); + +/* * The BCM1250, etc. PCI/HT bridge reports as a host bridge. */ static void quirk_sb1250_ht(struct pci_dev *dev) |