1 files changed, 91 insertions, 0 deletions
diff --git a/arch/mips/pci/fixup-sb1250.c b/arch/mips/pci/fixup-sb1250.c
new file mode 100644
index 000000000..3f914c33b
--- /dev/null
+++ b/arch/mips/pci/fixup-sb1250.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Copyright (C) 2004, 2006  MIPS Technologies, Inc.  All rights reserved.
+ *	    Author:	Maciej W. Rozycki <macro@mips.com>
+ *	Copyright (C) 2018  Maciej W. Rozycki
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/pci.h>
+
+/*
+ * Set the BCM1250, etc. PCI host bridge's TRDY timeout
+ * to the finite max.
+ */
+static void quirk_sb1250_pci(struct pci_dev *dev)
+{
+	pci_write_config_byte(dev, 0x40, 0xff);
+}
+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 limit 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 limit for devices present in the inclusive
+ * range of those.
+ */
+struct sb1250_bus_dma_limit_exclude {
+	bool set;
+	unsigned char start;
+	unsigned char end;
+};
+
+static int sb1250_bus_dma_limit(struct pci_dev *dev, void *data)
+{
+	struct sb1250_bus_dma_limit_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_limit = DMA_BIT_MASK(32);
+	}
+
+	return 0;
+}
+
+static void quirk_sb1250_pci_dac(struct pci_dev *dev)
+{
+	struct sb1250_bus_dma_limit_exclude exclude = { .set = false };
+
+	pci_walk_bus(dev->bus, sb1250_bus_dma_limit, &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)
+{
+	dev->class = PCI_CLASS_BRIDGE_PCI_NORMAL;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIBYTE, PCI_DEVICE_ID_BCM1250_HT,
+			quirk_sb1250_ht);
+
+/*
+ * Set the SP1011 HT/PCI bridge's TRDY timeout to the finite max.
+ */
+static void quirk_sp1011(struct pci_dev *dev)
+{
+	pci_write_config_byte(dev, 0x64, 0xff);
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIPACKETS, PCI_DEVICE_ID_SP1011,
+			quirk_sp1011);