MIPS: Lantiq: Add PCI controller support.

The Lantiq family of SoCs have a EBU (External Bus Unit). This patch adds
the driver that allows us to use the EBU as a PCI controller. In order for
PCI to work the EBU is set to endianess swap all the data. In addition we
need to make use of SWAP_IO_SPACE for device->host DMA to work.

The clock of the PCI works in several modes (internal/external). If this
is not configured correctly the SoC will hang.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2250/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mach-lantiq/lantiq_platform.h

@@ -0,0 +1,46 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ */
+
+#ifndef _LANTIQ_PLATFORM_H__
+#define _LANTIQ_PLATFORM_H__
+
+#include <linux/mtd/partitions.h>
+
+/* struct used to pass info to the pci core */
+enum {
+	PCI_CLOCK_INT = 0,
+	PCI_CLOCK_EXT
+};
+
+#define PCI_EXIN0	0x0001
+#define PCI_EXIN1	0x0002
+#define PCI_EXIN2	0x0004
+#define PCI_EXIN3	0x0008
+#define PCI_EXIN4	0x0010
+#define PCI_EXIN5	0x0020
+#define PCI_EXIN_MAX	6
+
+#define PCI_GNT1	0x0040
+#define PCI_GNT2	0x0080
+#define PCI_GNT3	0x0100
+#define PCI_GNT4	0x0200
+
+#define PCI_REQ1	0x0400
+#define PCI_REQ2	0x0800
+#define PCI_REQ3	0x1000
+#define PCI_REQ4	0x2000
+#define PCI_REQ_SHIFT	10
+#define PCI_REQ_MASK	0xf
+
+struct ltq_pci_data {
+	int clock;
+	int gpio;
+	int irq[16];
+};
+
+#endif

arch/mips/pci/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_SIBYTE_SB1250)	+= fixup-sb1250.o pci-sb1250.o
 obj-$(CONFIG_SIBYTE_BCM112X)	+= fixup-sb1250.o pci-sb1250.o
 obj-$(CONFIG_SIBYTE_BCM1x80)	+= pci-bcm1480.o pci-bcm1480ht.o
 obj-$(CONFIG_SNI_RM)		+= fixup-sni.o ops-sni.o
+obj-$(CONFIG_SOC_XWAY)		+= pci-lantiq.o ops-lantiq.o
 obj-$(CONFIG_TANBAC_TB0219)	+= fixup-tb0219.o
 obj-$(CONFIG_TANBAC_TB0226)	+= fixup-tb0226.o
 obj-$(CONFIG_TANBAC_TB0287)	+= fixup-tb0287.o

arch/mips/pci/ops-lantiq.c

@@ -0,0 +1,116 @@
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2010 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/types.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/mm.h>
+#include <asm/addrspace.h>
+#include <linux/vmalloc.h>
+
+#include <lantiq_soc.h>
+
+#include "pci-lantiq.h"
+
+#define LTQ_PCI_CFG_BUSNUM_SHF 16
+#define LTQ_PCI_CFG_DEVNUM_SHF 11
+#define LTQ_PCI_CFG_FUNNUM_SHF 8
+
+#define PCI_ACCESS_READ  0
+#define PCI_ACCESS_WRITE 1
+
+static int ltq_pci_config_access(unsigned char access_type, struct pci_bus *bus,
+	unsigned int devfn, unsigned int where, u32 *data)
+{
+	unsigned long cfg_base;
+	unsigned long flags;
+	u32 temp;
+
+	/* we support slot from 0 to 15 dev_fn & 0x68 (AD29) is the
+	   SoC itself */
+	if ((bus->number != 0) || ((devfn & 0xf8) > 0x78)
+		|| ((devfn & 0xf8) == 0) || ((devfn & 0xf8) == 0x68))
+		return 1;
+
+	spin_lock_irqsave(&ebu_lock, flags);
+
+	cfg_base = (unsigned long) ltq_pci_mapped_cfg;
+	cfg_base |= (bus->number << LTQ_PCI_CFG_BUSNUM_SHF) | (devfn <<
+			LTQ_PCI_CFG_FUNNUM_SHF) | (where & ~0x3);
+
+	/* Perform access */
+	if (access_type == PCI_ACCESS_WRITE) {
+		ltq_w32(swab32(*data), ((u32 *)cfg_base));
+	} else {
+		*data = ltq_r32(((u32 *)(cfg_base)));
+		*data = swab32(*data);
+	}
+	wmb();
+
+	/* clean possible Master abort */
+	cfg_base = (unsigned long) ltq_pci_mapped_cfg;
+	cfg_base |= (0x0 << LTQ_PCI_CFG_FUNNUM_SHF) + 4;
+	temp = ltq_r32(((u32 *)(cfg_base)));
+	temp = swab32(temp);
+	cfg_base = (unsigned long) ltq_pci_mapped_cfg;
+	cfg_base |= (0x68 << LTQ_PCI_CFG_FUNNUM_SHF) + 4;
+	ltq_w32(temp, ((u32 *)cfg_base));
+
+	spin_unlock_irqrestore(&ebu_lock, flags);
+
+	if (((*data) == 0xffffffff) && (access_type == PCI_ACCESS_READ))
+		return 1;
+
+	return 0;
+}
+
+int ltq_pci_read_config_dword(struct pci_bus *bus, unsigned int devfn,
+	int where, int size, u32 *val)
+{
+	u32 data = 0;
+
+	if (ltq_pci_config_access(PCI_ACCESS_READ, bus, devfn, where, &data))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	if (size == 1)
+		*val = (data >> ((where & 3) << 3)) & 0xff;
+	else if (size == 2)
+		*val = (data >> ((where & 3) << 3)) & 0xffff;
+	else
+		*val = data;
+
+	return PCIBIOS_SUCCESSFUL;
+}
+
+int ltq_pci_write_config_dword(struct pci_bus *bus, unsigned int devfn,
+	int where, int size, u32 val)
+{
+	u32 data = 0;
+
+	if (size == 4) {
+		data = val;
+	} else {
+		if (ltq_pci_config_access(PCI_ACCESS_READ, bus,
+				devfn, where, &data))
+			return PCIBIOS_DEVICE_NOT_FOUND;
+
+		if (size == 1)
+			data = (data & ~(0xff << ((where & 3) << 3))) |
+				(val << ((where & 3) << 3));
+		else if (size == 2)
+			data = (data & ~(0xffff << ((where & 3) << 3))) |
+				(val << ((where & 3) << 3));
+	}
+
+	if (ltq_pci_config_access(PCI_ACCESS_WRITE, bus, devfn, where, &data))
+		return PCIBIOS_DEVICE_NOT_FOUND;
+
+	return PCIBIOS_SUCCESSFUL;
+}