m68k: add PCI bus code support for the ColdFire M54xx SoC family

The ColdFire M54xx SoC family have a traditional PCI bus interface.
Add the core support code to access and use this bus on these parts.
This code provides all the config space access functions and IO access
functions. It also carries out the PCI bus initialization and hooks into
the kernel PCI subsystem.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>

2 files changed, 329 insertions, 0 deletions

diff --git a/arch/m68k/platform/coldfire/Makefile b/arch/m68k/platform/coldfire/Makefile
index 71bf542..02591a10 100644
--- a/arch/m68k/platform/coldfire/Makefile
+++ b/arch/m68k/platform/coldfire/Makefile
@@ -35,5 +35,7 @@ obj-$(CONFIG_CLEOPATRA)	+= nettel.o
 obj-$(CONFIG_FIREBEE)	+= firebee.o
 obj-$(CONFIG_MCF8390)	+= mcf8390.o
 
+obj-$(CONFIG_PCI)	+= pci.o
+
 obj-y			+= gpio.o
 extra-y := head.o
diff --git a/arch/m68k/platform/coldfire/pci.c b/arch/m68k/platform/coldfire/pci.c
new file mode 100644
index 0000000..553210d
--- /dev/null
+++ b/arch/m68k/platform/coldfire/pci.c
@@ -0,0 +1,327 @@
+/*
+ * pci.c -- PCI bus support for ColdFire processors
+ *
+ * (C) Copyright 2012, Greg Ungerer <gerg@uclinux.com>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+#include <asm/m54xxpci.h>
+
+/*
+ * Memory and IO mappings. We use a 1:1 mapping for local host memory to
+ * PCI bus memory (no reason not to really). IO space doesn't matter, we
+ * always use access functions for that. The device configuration space is
+ * mapped over the IO map space when we enable it in the PCICAR register.
+ */
+#define	PCI_MEM_PA	0xf0000000		/* Host physical address */
+#define	PCI_MEM_BA	0xf0000000		/* Bus physical address */
+#define	PCI_MEM_SIZE	0x08000000		/* 128 MB */
+#define	PCI_MEM_MASK	(PCI_MEM_SIZE - 1)
+
+#define	PCI_IO_PA	0xf8000000		/* Host physical address */
+#define	PCI_IO_BA	0x00000000		/* Bus physical address */
+#define	PCI_IO_SIZE	0x00010000		/* 64k */
+#define	PCI_IO_MASK	(PCI_IO_SIZE - 1)
+
+static struct pci_bus *rootbus;
+static unsigned long iospace;
+
+/*
+ * We need to be carefull probing on bus 0 (directly connected to host
+ * bridge). We should only acccess the well defined possible devices in
+ * use, ignore aliases and the like.
+ */
+static unsigned char mcf_host_slot2sid[32] = {
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+	0, 1, 2, 0, 3, 4, 0, 0,
+	0, 0, 0, 0, 0, 0, 0, 0,
+};
+
+static unsigned char mcf_host_irq[] = {
+	0, 69, 69, 71, 71,
+};
+
+
+static inline void syncio(void)
+{
+	/* The ColdFire "nop" instruction waits for all bus IO to complete */
+	__asm__ __volatile__ ("nop");
+}
+
+/*
+ * Configuration space access functions. Configuration space access is
+ * through the IO mapping window, enabling it via the PCICAR register.
+ */
+static unsigned long mcf_mk_pcicar(int bus, unsigned int devfn, int where)
+{
+	return (bus << PCICAR_BUSN) | (devfn << PCICAR_DEVFNN) | (where & 0xfc);
+}
+
+static int mcf_pci_readconfig(struct pci_bus *bus, unsigned int devfn,
+	int where, int size, u32 *value)
+{
+	unsigned long addr;
+
+	*value = 0xffffffff;
+
+	if (bus->number == 0) {
+		if (mcf_host_slot2sid[PCI_SLOT(devfn)] == 0)
+			return PCIBIOS_SUCCESSFUL;
+	}
+
+	syncio();
+	addr = mcf_mk_pcicar(bus->number, devfn, where);
+	__raw_writel(PCICAR_E | addr, PCICAR);
+	addr = iospace + (where & 0x3);
+
+	switch (size) {
+	case 1:
+		*value = __raw_readb(addr);
+		break;
+	case 2:
+		*value = le16_to_cpu(__raw_readw(addr));
+		break;
+	default:
+		*value = le32_to_cpu(__raw_readl(addr));
+		break;
+	}
+
+	syncio();
+	__raw_writel(0, PCICAR);
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static int mcf_pci_writeconfig(struct pci_bus *bus, unsigned int devfn,
+	int where, int size, u32 value)
+{
+	unsigned long addr;
+
+	if (bus->number == 0) {
+		if (mcf_host_slot2sid[PCI_SLOT(devfn)] == 0)
+			return PCIBIOS_SUCCESSFUL;
+	}
+
+	syncio();
+	addr = mcf_mk_pcicar(bus->number, devfn, where);
+	__raw_writel(PCICAR_E | addr, PCICAR);
+	addr = iospace + (where & 0x3);
+
+	switch (size) {
+	case 1:
+		 __raw_writeb(value, addr);
+		break;
+	case 2:
+		__raw_writew(cpu_to_le16(value), addr);
+		break;
+	default:
+		__raw_writel(cpu_to_le32(value), addr);
+		break;
+	}
+
+	syncio();
+	__raw_writel(0, PCICAR);
+	return PCIBIOS_SUCCESSFUL;
+}
+
+static struct pci_ops mcf_pci_ops = {
+	.read	= mcf_pci_readconfig,
+	.write	= mcf_pci_writeconfig,
+};
+
+/*
+ *	IO address space access functions. Pretty strait forward, these are
+ *	directly mapped in to the IO mapping window. And that is mapped into
+ *	virtual address space.
+ */
+u8 mcf_pci_inb(u32 addr)
+{
+	return __raw_readb(iospace + (addr & PCI_IO_MASK));
+}
+EXPORT_SYMBOL(mcf_pci_inb);
+
+u16 mcf_pci_inw(u32 addr)
+{
+	return le16_to_cpu(__raw_readw(iospace + (addr & PCI_IO_MASK)));
+}
+EXPORT_SYMBOL(mcf_pci_inw);
+
+u32 mcf_pci_inl(u32 addr)
+{
+	return le32_to_cpu(__raw_readl(iospace + (addr & PCI_IO_MASK)));
+}
+EXPORT_SYMBOL(mcf_pci_inl);
+
+void mcf_pci_insb(u32 addr, u8 *buf, u32 len)
+{
+	for (; len; len--)
+		*buf++ = mcf_pci_inb(addr);
+}
+EXPORT_SYMBOL(mcf_pci_insb);
+
+void mcf_pci_insw(u32 addr, u16 *buf, u32 len)
+{
+	for (; len; len--)
+		*buf++ = mcf_pci_inw(addr);
+}
+EXPORT_SYMBOL(mcf_pci_insw);
+
+void mcf_pci_insl(u32 addr, u32 *buf, u32 len)
+{
+	for (; len; len--)
+		*buf++ = mcf_pci_inl(addr);
+}
+EXPORT_SYMBOL(mcf_pci_insl);
+
+void mcf_pci_outb(u8 v, u32 addr)
+{
+	__raw_writeb(v, iospace + (addr & PCI_IO_MASK));
+}
+EXPORT_SYMBOL(mcf_pci_outb);
+
+void mcf_pci_outw(u16 v, u32 addr)
+{
+	__raw_writew(cpu_to_le16(v), iospace + (addr & PCI_IO_MASK));
+}
+EXPORT_SYMBOL(mcf_pci_outw);
+
+void mcf_pci_outl(u32 v, u32 addr)
+{
+	__raw_writel(cpu_to_le32(v), iospace + (addr & PCI_IO_MASK));
+}
+EXPORT_SYMBOL(mcf_pci_outl);
+
+void mcf_pci_outsb(u32 addr, const u8 *buf, u32 len)
+{
+	for (; len; len--)
+		mcf_pci_outb(*buf++, addr);
+}
+EXPORT_SYMBOL(mcf_pci_outsb);
+
+void mcf_pci_outsw(u32 addr, const u16 *buf, u32 len)
+{
+	for (; len; len--)
+		mcf_pci_outw(*buf++, addr);
+}
+EXPORT_SYMBOL(mcf_pci_outsw);
+
+void mcf_pci_outsl(u32 addr, const u32 *buf, u32 len)
+{
+	for (; len; len--)
+		mcf_pci_outl(*buf++, addr);
+}
+EXPORT_SYMBOL(mcf_pci_outsl);
+
+/*
+ * Initialize the PCI bus registers, and scan the bus.
+ */
+static struct resource mcf_pci_mem = {
+	.name	= "PCI Memory space",
+	.start	= PCI_MEM_PA,
+	.end	= PCI_MEM_PA + PCI_MEM_SIZE - 1,
+	.flags	= IORESOURCE_MEM,
+};
+
+static struct resource mcf_pci_io = {
+	.name	= "PCI IO space",
+	.start	= 0x400,
+	.end	= 0x10000 - 1,
+	.flags	= IORESOURCE_IO,
+};
+
+/*
+ * Interrupt mapping and setting.
+ */
+static int mcf_pci_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
+{
+	int sid;
+
+	sid = mcf_host_slot2sid[slot];
+	if (sid)
+		return mcf_host_irq[sid];
+	return 0;
+}
+
+static int __init mcf_pci_init(void)
+{
+	pr_info("ColdFire: PCI bus initialization...\n");
+
+	/* Reset the external PCI bus */
+	__raw_writel(PCIGSCR_RESET, PCIGSCR);
+	__raw_writel(0, PCITCR);
+
+	request_resource(&iomem_resource, &mcf_pci_mem);
+	request_resource(&iomem_resource, &mcf_pci_io);
+
+	/* Configure PCI arbiter */
+	__raw_writel(PACR_INTMPRI | PACR_INTMINTE | PACR_EXTMPRI(0x1f) |
+		PACR_EXTMINTE(0x1f), PACR);
+
+	/* Set required multi-function pins for PCI bus use */
+	__raw_writew(0x3ff, MCF_PAR_PCIBG);
+	__raw_writew(0x3ff, MCF_PAR_PCIBR);
+
+	/* Set up config space for local host bus controller */
+	__raw_writel(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
+		PCI_COMMAND_INVALIDATE, PCISCR);
+	__raw_writel(PCICR1_LT(32) | PCICR1_CL(8), PCICR1);
+	__raw_writel(0, PCICR2);
+
+	/*
+	 * Set up the initiator windows for memory and IO mapping.
+	 * These give the CPU bus access onto the PCI bus. One for each of
+	 * PCI memory and IO address spaces.
+	 */
+	__raw_writel(WXBTAR(PCI_MEM_PA, PCI_MEM_BA, PCI_MEM_SIZE),
+		PCIIW0BTAR);
+	__raw_writel(WXBTAR(PCI_IO_PA, PCI_IO_BA, PCI_IO_SIZE),
+		PCIIW1BTAR);
+	__raw_writel(PCIIWCR_W0_MEM /*| PCIIWCR_W0_MRDL*/ | PCIIWCR_W0_E |
+		PCIIWCR_W1_IO | PCIIWCR_W1_E, PCIIWCR);
+
+	/*
+	 * Set up the target windows for access from the PCI bus back to the
+	 * CPU bus. All we need is access to system RAM (for mastering).
+	 */
+	__raw_writel(CONFIG_RAMBASE, PCIBAR1);
+	__raw_writel(CONFIG_RAMBASE | PCITBATR1_E, PCITBATR1);
+
+	/* Keep a virtual mapping to IO/config space active */
+	iospace = (unsigned long) ioremap(PCI_IO_PA, PCI_IO_SIZE);
+	if (iospace == 0)
+		return -ENODEV;
+	pr_info("Coldfire: PCI IO/config window mapped to 0x%x\n",
+		(u32) iospace);
+
+	/* Turn of PCI reset, and wait for devices to settle */
+	__raw_writel(0, PCIGSCR);
+	set_current_state(TASK_UNINTERRUPTIBLE);
+	schedule_timeout(msecs_to_jiffies(200));
+
+	rootbus = pci_scan_bus(0, &mcf_pci_ops, NULL);
+	rootbus->resource[0] = &mcf_pci_io;
+	rootbus->resource[1] = &mcf_pci_mem;
+
+	pci_fixup_irqs(pci_common_swizzle, mcf_pci_map_irq);
+	pci_bus_size_bridges(rootbus);
+	pci_bus_assign_resources(rootbus);
+	pci_enable_bridges(rootbus);
+	pci_bus_add_devices(rootbus);
+	return 0;
+}
+
+subsys_initcall(mcf_pci_init);