m68k: common PCI support definitions and code

Basic set of definitions and support code required to turn on CONFIG_PCI
for the m68k architecture. Nothing specific to any PCI implementation in
any m68k class CPU hardware yet.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

1 files changed, 109 insertions, 0 deletions

diff --git a/arch/m68k/kernel/pcibios.c b/arch/m68k/kernel/pcibios.c
new file mode 100644
index 00000000000..b2988aa1840
--- /dev/null
+++ b/arch/m68k/kernel/pcibios.c
@@ -0,0 +1,109 @@
+/*
+ * pci.c -- basic PCI support code
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ *
+ * (C) Copyright 2011, Greg Ungerer <gerg@uclinux.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+
+/*
+ * From arch/i386/kernel/pci-i386.c:
+ *
+ * We need to avoid collisions with `mirrored' VGA ports
+ * and other strange ISA hardware, so we always want the
+ * addresses to be allocated in the 0x000-0x0ff region
+ * modulo 0x400.
+ *
+ * Why? Because some silly external IO cards only decode
+ * the low 10 bits of the IO address. The 0x00-0xff region
+ * is reserved for motherboard devices that decode all 16
+ * bits, so it's ok to allocate at, say, 0x2800-0x28ff,
+ * but we want to try to avoid allocating at 0x2900-0x2bff
+ * which might be mirrored at 0x0100-0x03ff..
+ */
+resource_size_t pcibios_align_resource(void *data, const struct resource *res,
+	resource_size_t size, resource_size_t align)
+{
+	resource_size_t start = res->start;
+
+	if ((res->flags & IORESOURCE_IO) && (start & 0x300))
+		start = (start + 0x3ff) & ~0x3ff;
+
+	start = (start + align - 1) & ~(align - 1);
+
+	return start;
+}
+
+/*
+ * This is taken from the ARM code for this.
+ */
+int pcibios_enable_device(struct pci_dev *dev, int mask)
+{
+	struct resource *r;
+	u16 cmd, newcmd;
+	int idx;
+
+	pci_read_config_word(dev, PCI_COMMAND, &cmd);
+	newcmd = cmd;
+
+	for (idx = 0; idx < 6; idx++) {
+		/* Only set up the requested stuff */
+		if (!(mask & (1 << idx)))
+			continue;
+
+		r = dev->resource + idx;
+		if (!r->start && r->end) {
+			pr_err(KERN_ERR "PCI: Device %s not available because of resource collisions\n",
+				pci_name(dev));
+			return -EINVAL;
+		}
+		if (r->flags & IORESOURCE_IO)
+			newcmd |= PCI_COMMAND_IO;
+		if (r->flags & IORESOURCE_MEM)
+			newcmd |= PCI_COMMAND_MEMORY;
+	}
+
+	/*
+	 * Bridges (eg, cardbus bridges) need to be fully enabled
+	 */
+	if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE)
+		newcmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY;
+
+
+	if (newcmd != cmd) {
+		pr_info("PCI: enabling device %s (0x%04x -> 0x%04x)\n",
+			pci_name(dev), cmd, newcmd);
+		pci_write_config_word(dev, PCI_COMMAND, newcmd);
+	}
+	return 0;
+}
+
+void pcibios_update_irq(struct pci_dev *dev, int irq)
+{
+	pci_write_config_byte(dev, PCI_INTERRUPT_LINE, irq);
+}
+
+void __devinit pcibios_fixup_bus(struct pci_bus *bus)
+{
+	struct pci_dev *dev;
+
+	list_for_each_entry(dev, &bus->devices, bus_list) {
+		pci_write_config_byte(dev, PCI_CACHE_LINE_SIZE, 8);
+		pci_write_config_byte(dev, PCI_LATENCY_TIMER, 32);
+	}
+}
+
+char __devinit *pcibios_setup(char *str)
+{
+	return str;
+}
+