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-rw-r--r--arch/mips/pci/fixup-sb1250.c53
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)