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>

1 files changed, 116 insertions, 0 deletions

diff --git a/arch/mips/pci/ops-lantiq.c b/arch/mips/pci/ops-lantiq.c
new file mode 100644
index 000000000000..1f2afb55cc71
--- /dev/null
+++ b/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;
+}