bus: introduce an Marvell EBU MBus driver

The Marvell EBU SoCs have a configurable physical address space
layout: the physical ranges of memory used to address PCI(e)
interfaces, NOR flashes, SRAM and various other types of memory are
configurable by software, through a mechanism of so-called 'address
decoding windows'.

This new driver mvebu-mbus consolidates the existing code to address
the configuration of these memory ranges, which is spread into
mach-mvebu, mach-orion5x, mach-mv78xx0, mach-dove and mach-kirkwood.

Following patches convert each Marvell EBU SoC family to use this
driver, therefore removing the old code that was configuring the
address decoding windows.

It is worth mentioning that the MVEBU_MBUS Kconfig option is
intentionally added as a blind option. The new driver implements and
exports the mv_mbus_dram_info() function, which is used by various
Marvell drivers throughout the tree to get access to window
configuration parameters that they require. This function is also
implemented in arch/arm/plat-orion/addr-map.c, which ultimately gets
removed at the end of this patch series. So, in order to preserve
bisectability, we want to ensure that *either* this new driver, *or*
the legacy code in plat-orion/addr-map.c gets compiled in.

By making MVEBU_MBUS a blind option, we are sure that only a platform
that does 'select MVEBU_MBUS' will get this new driver compiled
in. Therefore, throughout the next patches that convert the Marvell
sub-architectures one after the other to this new driver, we add the
'select MVEBU_MBUS' and also ensure to remove plat-orion/addr-map.c
from the build for this specific sub-architecture. This ensures that
bisectability is preserved.

Ealier versions of this driver had a DT binding, but since those were
not yet agreed upon, they were removed. The driver still uses
of_device_id to find the SoC specific details according to the string
passed to mvebu_mbus_init(). The plan is to re-introduce a proper DT
binding as a followup set of patches.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NJason Cooper <jason@lakedaemon.net>

drivers/bus/Kconfig

@@ -4,6 +4,13 @@
 
 menu "Bus devices"
 
+config MVEBU_MBUS
+	bool
+	depends on PLAT_ORION
+	help
+	  Driver needed for the MBus configuration on Marvell EBU SoCs
+	  (Kirkwood, Dove, Orion5x, MV78XX0 and Armada 370/XP).
+
 config OMAP_OCP2SCP
 	tristate "OMAP OCP2SCP DRIVER"
 	depends on ARCH_OMAP2PLUS

drivers/bus/Makefile

@@ -2,6 +2,7 @@
 # Makefile for the bus drivers.
 #
 
+obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
 obj-$(CONFIG_OMAP_OCP2SCP)	+= omap-ocp2scp.o
 
 # Interconnect bus driver for OMAP SoCs.

drivers/bus/mvebu-mbus.c

+/*
+ * Address map functions for Marvell EBU SoCs (Kirkwood, Armada
+ * 370/XP, Dove, Orion5x and MV78xx0)
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2.  This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * The Marvell EBU SoCs have a configurable physical address space:
+ * the physical address at which certain devices (PCIe, NOR, NAND,
+ * etc.) sit can be configured. The configuration takes place through
+ * two sets of registers:
+ *
+ * - One to configure the access of the CPU to the devices. Depending
+ *   on the families, there are between 8 and 20 configurable windows,
+ *   each can be use to create a physical memory window that maps to a
+ *   specific device. Devices are identified by a tuple (target,
+ *   attribute).
+ *
+ * - One to configure the access to the CPU to the SDRAM. There are
+ *   either 2 (for Dove) or 4 (for other families) windows to map the
+ *   SDRAM into the physical address space.
+ *
+ * This driver:
+ *
+ * - Reads out the SDRAM address decoding windows at initialization
+ *   time, and fills the mvebu_mbus_dram_info structure with these
+ *   informations. The exported function mv_mbus_dram_info() allow
+ *   device drivers to get those informations related to the SDRAM
+ *   address decoding windows. This is because devices also have their
+ *   own windows (configured through registers that are part of each
+ *   device register space), and therefore the drivers for Marvell
+ *   devices have to configure those device -> SDRAM windows to ensure
+ *   that DMA works properly.
+ *
+ * - Provides an API for platform code or device drivers to
+ *   dynamically add or remove address decoding windows for the CPU ->
+ *   device accesses. This API is mvebu_mbus_add_window(),
+ *   mvebu_mbus_add_window_remap_flags() and
+ *   mvebu_mbus_del_window(). Since the (target, attribute) values
+ *   differ from one SoC family to another, the API uses a 'const char
+ *   *' string to identify devices, and this driver is responsible for
+ *   knowing the mapping between the name of a device and its
+ *   corresponding (target, attribute) in the current SoC family.
+ *
+ * - Provides a debugfs interface in /sys/kernel/debug/mvebu-mbus/ to
+ *   see the list of CPU -> SDRAM windows and their configuration
+ *   (file 'sdram') and the list of CPU -> devices windows and their
+ *   configuration (file 'devices').
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/mbus.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/debugfs.h>
+
+/*
+ * DDR target is the same on all platforms.
+ */
+#define TARGET_DDR		0
+
+/*
+ * CPU Address Decode Windows registers
+ */
+#define WIN_CTRL_OFF		0x0000
+#define   WIN_CTRL_ENABLE       BIT(0)
+#define   WIN_CTRL_TGT_MASK     0xf0
+#define   WIN_CTRL_TGT_SHIFT    4
+#define   WIN_CTRL_ATTR_MASK    0xff00
+#define   WIN_CTRL_ATTR_SHIFT   8
+#define   WIN_CTRL_SIZE_MASK    0xffff0000
+#define   WIN_CTRL_SIZE_SHIFT   16
+#define WIN_BASE_OFF		0x0004
+#define   WIN_BASE_LOW          0xffff0000
+#define   WIN_BASE_HIGH         0xf
+#define WIN_REMAP_LO_OFF	0x0008
+#define   WIN_REMAP_LOW         0xffff0000
+#define WIN_REMAP_HI_OFF	0x000c
+
+#define ATTR_HW_COHERENCY	(0x1 << 4)
+
+#define DDR_BASE_CS_OFF(n)	(0x0000 + ((n) << 3))
+#define  DDR_BASE_CS_HIGH_MASK  0xf
+#define  DDR_BASE_CS_LOW_MASK   0xff000000
+#define DDR_SIZE_CS_OFF(n)	(0x0004 + ((n) << 3))
+#define  DDR_SIZE_ENABLED       BIT(0)
+#define  DDR_SIZE_CS_MASK       0x1c
+#define  DDR_SIZE_CS_SHIFT      2
+#define  DDR_SIZE_MASK          0xff000000
+
+#define DOVE_DDR_BASE_CS_OFF(n) ((n) << 4)
+
+struct mvebu_mbus_mapping {
+	const char *name;
+	u8 target;
+	u8 attr;
+	u8 attrmask;
+};
+
+/*
+ * Masks used for the 'attrmask' field of mvebu_mbus_mapping. They
+ * allow to get the real attribute value, discarding the special bits
+ * used to select a PCI MEM region or a PCI WA region. This allows the
+ * debugfs code to reverse-match the name of a device from its
+ * target/attr values.
+ *
+ * For all devices except PCI, all bits of 'attr' must be
+ * considered. For most SoCs, only bit 3 should be ignored (it allows
+ * to select between PCI MEM and PCI I/O). On Orion5x however, there
+ * is the special bit 5 to select a PCI WA region.
+ */
+#define MAPDEF_NOMASK       0xff
+#define MAPDEF_PCIMASK      0xf7
+#define MAPDEF_ORIONPCIMASK 0xd7
+
+/* Macro used to define one mvebu_mbus_mapping entry */
+#define MAPDEF(__n, __t, __a, __m) \
+	{ .name = __n, .target = __t, .attr = __a, .attrmask = __m }
+
+struct mvebu_mbus_state;
+
+struct mvebu_mbus_soc_data {
+	unsigned int num_wins;
+	unsigned int num_remappable_wins;
+	unsigned int (*win_cfg_offset)(const int win);
+	void (*setup_cpu_target)(struct mvebu_mbus_state *s);
+	int (*show_cpu_target)(struct mvebu_mbus_state *s,
+			       struct seq_file *seq, void *v);
+	const struct mvebu_mbus_mapping *map;
+};
+
+struct mvebu_mbus_state {
+	void __iomem *mbuswins_base;
+	void __iomem *sdramwins_base;
+	struct dentry *debugfs_root;
+	struct dentry *debugfs_sdram;
+	struct dentry *debugfs_devs;
+	const struct mvebu_mbus_soc_data *soc;
+	int hw_io_coherency;
+};
+
+static struct mvebu_mbus_state mbus_state;
+
+static struct mbus_dram_target_info mvebu_mbus_dram_info;
+const struct mbus_dram_target_info *mv_mbus_dram_info(void)
+{
+	return &mvebu_mbus_dram_info;
+}
+EXPORT_SYMBOL_GPL(mv_mbus_dram_info);
+
+/*
+ * Functions to manipulate the address decoding windows
+ */
+
+static void mvebu_mbus_read_window(struct mvebu_mbus_state *mbus,
+				   int win, int *enabled, u64 *base,
+				   u32 *size, u8 *target, u8 *attr,
+				   u64 *remap)
+{
+	void __iomem *addr = mbus->mbuswins_base +
+		mbus->soc->win_cfg_offset(win);
+	u32 basereg = readl(addr + WIN_BASE_OFF);
+	u32 ctrlreg = readl(addr + WIN_CTRL_OFF);
+
+	if (!(ctrlreg & WIN_CTRL_ENABLE)) {
+		*enabled = 0;
+		return;
+	}
+
+	*enabled = 1;
+	*base = ((u64)basereg & WIN_BASE_HIGH) << 32;
+	*base |= (basereg & WIN_BASE_LOW);
+	*size = (ctrlreg | ~WIN_CTRL_SIZE_MASK) + 1;
+
+	if (target)
+		*target = (ctrlreg & WIN_CTRL_TGT_MASK) >> WIN_CTRL_TGT_SHIFT;
+
+	if (attr)
+		*attr = (ctrlreg & WIN_CTRL_ATTR_MASK) >> WIN_CTRL_ATTR_SHIFT;
+
+	if (remap) {
+		if (win < mbus->soc->num_remappable_wins) {
+			u32 remap_low = readl(addr + WIN_REMAP_LO_OFF);
+			u32 remap_hi  = readl(addr + WIN_REMAP_HI_OFF);
+			*remap = ((u64)remap_hi << 32) | remap_low;
+		} else
+			*remap = 0;
+	}
+}
+
+static void mvebu_mbus_disable_window(struct mvebu_mbus_state *mbus,
+				      int win)
+{
+	void __iomem *addr;
+
+	addr = mbus->mbuswins_base + mbus->soc->win_cfg_offset(win);
+
+	writel(0, addr + WIN_BASE_OFF);
+	writel(0, addr + WIN_CTRL_OFF);
+	if (win < mbus->soc->num_remappable_wins) {
+		writel(0, addr + WIN_REMAP_LO_OFF);
+		writel(0, addr + WIN_REMAP_HI_OFF);
+	}
+}
+
+/* Checks whether the given window number is available */
+static int mvebu_mbus_window_is_free(struct mvebu_mbus_state *mbus,
+				     const int win)
+{
+	void __iomem *addr = mbus->mbuswins_base +
+		mbus->soc->win_cfg_offset(win);
+	u32 ctrl = readl(addr + WIN_CTRL_OFF);
+	return !(ctrl & WIN_CTRL_ENABLE);
+}
+
+/*
+ * Checks whether the given (base, base+size) area doesn't overlap an
+ * existing region
+ */
+static int mvebu_mbus_window_conflicts(struct mvebu_mbus_state *mbus,
+				       phys_addr_t base, size_t size,
+				       u8 target, u8 attr)
+{
+	u64 end = (u64)base + size;
+	int win;
+
+	for (win = 0; win < mbus->soc->num_wins; win++) {
+		u64 wbase, wend;
+		u32 wsize;
+		u8 wtarget, wattr;
+		int enabled;
+
+		mvebu_mbus_read_window(mbus, win,
+				       &enabled, &wbase, &wsize,
+				       &wtarget, &wattr, NULL);
+
+		if (!enabled)
+			continue;
+
+		wend = wbase + wsize;
+
+		/*
+		 * Check if the current window overlaps with the
+		 * proposed physical range
+		 */
+		if ((u64)base < wend && end > wbase)
+			return 0;
+
+		/*
+		 * Check if target/attribute conflicts
+		 */
+		if (target == wtarget && attr == wattr)
+			return 0;
+	}
+
+	return 1;
+}
+
+static int mvebu_mbus_find_window(struct mvebu_mbus_state *mbus,
+				  phys_addr_t base, size_t size)
+{
+	int win;
+
+	for (win = 0; win < mbus->soc->num_wins; win++) {
+		u64 wbase;
+		u32 wsize;
+		int enabled;
+
+		mvebu_mbus_read_window(mbus, win,
+				       &enabled, &wbase, &wsize,
+				       NULL, NULL, NULL);
+
+		if (!enabled)
+			continue;
+
+		if (base == wbase && size == wsize)
+			return win;
+	}
+
+	return -ENODEV;
+}
+
+static int mvebu_mbus_setup_window(struct mvebu_mbus_state *mbus,
+				   int win, phys_addr_t base, size_t size,
+				   phys_addr_t remap, u8 target,
+				   u8 attr)
+{
+	void __iomem *addr = mbus->mbuswins_base +
+		mbus->soc->win_cfg_offset(win);
+	u32 ctrl, remap_addr;
+
+	ctrl = ((size - 1) & WIN_CTRL_SIZE_MASK) |
+		(attr << WIN_CTRL_ATTR_SHIFT)    |
+		(target << WIN_CTRL_TGT_SHIFT)   |
+		WIN_CTRL_ENABLE;
+
+	writel(base & WIN_BASE_LOW, addr + WIN_BASE_OFF);
+	writel(ctrl, addr + WIN_CTRL_OFF);
+	if (win < mbus->soc->num_remappable_wins) {
+		if (remap == MVEBU_MBUS_NO_REMAP)
+			remap_addr = base;
+		else
+			remap_addr = remap;
+		writel(remap_addr & WIN_REMAP_LOW, addr + WIN_REMAP_LO_OFF);
+		writel(0, addr + WIN_REMAP_HI_OFF);
+	}
+
+	return 0;
+}
+
+static int mvebu_mbus_alloc_window(struct mvebu_mbus_state *mbus,
+				   phys_addr_t base, size_t size,
+				   phys_addr_t remap, u8 target,
+				   u8 attr)
+{
+	int win;
+
+	if (remap == MVEBU_MBUS_NO_REMAP) {
+		for (win = mbus->soc->num_remappable_wins;
+		     win < mbus->soc->num_wins; win++)
+			if (mvebu_mbus_window_is_free(mbus, win))
+				return mvebu_mbus_setup_window(mbus, win, base,
+							       size, remap,
+							       target, attr);
+	}
+
+
+	for (win = 0; win < mbus->soc->num_wins; win++)
+		if (mvebu_mbus_window_is_free(mbus, win))
+			return mvebu_mbus_setup_window(mbus, win, base, size,
+						       remap, target, attr);
+
+	return -ENOMEM;
+}
+
+/*
+ * Debugfs debugging
+ */
+
+/* Common function used for Dove, Kirkwood, Armada 370/XP and Orion 5x */
+static int mvebu_sdram_debug_show_orion(struct mvebu_mbus_state *mbus,
+					struct seq_file *seq, void *v)
+{
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		u32 basereg = readl(mbus->sdramwins_base + DDR_BASE_CS_OFF(i));
+		u32 sizereg = readl(mbus->sdramwins_base + DDR_SIZE_CS_OFF(i));
+		u64 base;
+		u32 size;
+
+		if (!(sizereg & DDR_SIZE_ENABLED)) {
+			seq_printf(seq, "[%d] disabled\n", i);
+			continue;
+		}
+
+		base = ((u64)basereg & DDR_BASE_CS_HIGH_MASK) << 32;
+		base |= basereg & DDR_BASE_CS_LOW_MASK;
+		size = (sizereg | ~DDR_SIZE_MASK);
+
+		seq_printf(seq, "[%d] %016llx - %016llx : cs%d\n",
+			   i, (unsigned long long)base,
+			   (unsigned long long)base + size + 1,
+			   (sizereg & DDR_SIZE_CS_MASK) >> DDR_SIZE_CS_SHIFT);
+	}
+
+	return 0;
+}
+
+/* Special function for Dove */
+static int mvebu_sdram_debug_show_dove(struct mvebu_mbus_state *mbus,
+				       struct seq_file *seq, void *v)
+{
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		u32 map = readl(mbus->sdramwins_base + DOVE_DDR_BASE_CS_OFF(i));
+		u64 base;
+		u32 size;
+
+		if (!(map & 1)) {
+			seq_printf(seq, "[%d] disabled\n", i);
+			continue;
+		}
+
+		base = map & 0xff800000;
+		size = 0x100000 << (((map & 0x000f0000) >> 16) - 4);
+
+		seq_printf(seq, "[%d] %016llx - %016llx : cs%d\n",
+			   i, (unsigned long long)base,
+			   (unsigned long long)base + size, i);
+	}
+
+	return 0;
+}
+
+static int mvebu_sdram_debug_show(struct seq_file *seq, void *v)
+{
+	struct mvebu_mbus_state *mbus = &mbus_state;
+	return mbus->soc->show_cpu_target(mbus, seq, v);
+}
+
+static int mvebu_sdram_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, mvebu_sdram_debug_show, inode->i_private);
+}
+
+static const struct file_operations mvebu_sdram_debug_fops = {
+	.open = mvebu_sdram_debug_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int mvebu_devs_debug_show(struct seq_file *seq, void *v)
+{
+	struct mvebu_mbus_state *mbus = &mbus_state;
+	int win;
+
+	for (win = 0; win < mbus->soc->num_wins; win++) {
+		u64 wbase, wremap;
+		u32 wsize;
+		u8 wtarget, wattr;
+		int enabled, i;
+		const char *name;
+
+		mvebu_mbus_read_window(mbus, win,
+				       &enabled, &wbase, &wsize,
+				       &wtarget, &wattr, &wremap);
+
+		if (!enabled) {
+			seq_printf(seq, "[%02d] disabled\n", win);
+			continue;
+		}
+
+
+		for (i = 0; mbus->soc->map[i].name; i++)
+			if (mbus->soc->map[i].target == wtarget &&
+			    mbus->soc->map[i].attr ==
+			    (wattr & mbus->soc->map[i].attrmask))
+				break;
+
+		name = mbus->soc->map[i].name ?: "unknown";
+
+		seq_printf(seq, "[%02d] %016llx - %016llx : %s",
+			   win, (unsigned long long)wbase,
+			   (unsigned long long)(wbase + wsize), name);
+
+		if (win < mbus->soc->num_remappable_wins) {
+			seq_printf(seq, " (remap %016llx)\n",
+				   (unsigned long long)wremap);
+		} else
+			seq_printf(seq, "\n");
+	}
+
+	return 0;
+}
+
+static int mvebu_devs_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, mvebu_devs_debug_show, inode->i_private);
+}
+
+static const struct file_operations mvebu_devs_debug_fops = {
+	.open = mvebu_devs_debug_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+/*
+ * SoC-specific functions and definitions
+ */
+
+static unsigned int orion_mbus_win_offset(int win)
+{
+	return win << 4;
+}
+
+static unsigned int armada_370_xp_mbus_win_offset(int win)
+{
+	/* The register layout is a bit annoying and the below code
+	 * tries to cope with it.
+	 * - At offset 0x0, there are the registers for the first 8
+	 *   windows, with 4 registers of 32 bits per window (ctrl,
+	 *   base, remap low, remap high)
+	 * - Then at offset 0x80, there is a hole of 0x10 bytes for
+	 *   the internal registers base address and internal units
+	 *   sync barrier register.
+	 * - Then at offset 0x90, there the registers for 12
+	 *   windows, with only 2 registers of 32 bits per window
+	 *   (ctrl, base).
+	 */
+	if (win < 8)
+		return win << 4;
+	else
+		return 0x90 + ((win - 8) << 3);
+}
+
+static unsigned int mv78xx0_mbus_win_offset(int win)
+{
+	if (win < 8)
+		return win << 4;
+	else
+		return 0x900 + ((win - 8) << 4);
+}
+
+static void __init
+mvebu_mbus_default_setup_cpu_target(struct mvebu_mbus_state *mbus)
+{
+	int i;
+	int cs;
+
+	mvebu_mbus_dram_info.mbus_dram_target_id = TARGET_DDR;
+
+	for (i = 0, cs = 0; i < 4; i++) {
+		u32 base = readl(mbus->sdramwins_base + DDR_BASE_CS_OFF(i));
+		u32 size = readl(mbus->sdramwins_base + DDR_SIZE_CS_OFF(i));
+
+		/*
+		 * We only take care of entries for which the chip
+		 * select is enabled, and that don't have high base
+		 * address bits set (devices can only access the first
+		 * 32 bits of the memory).
+		 */
+		if ((size & DDR_SIZE_ENABLED) &&
+		    !(base & DDR_BASE_CS_HIGH_MASK)) {
+			struct mbus_dram_window *w;
+
+			w = &mvebu_mbus_dram_info.cs[cs++];
+			w->cs_index = i;
+			w->mbus_attr = 0xf & ~(1 << i);
+			if (mbus->hw_io_coherency)
+				w->mbus_attr |= ATTR_HW_COHERENCY;
+			w->base = base & DDR_BASE_CS_LOW_MASK;
+			w->size = (size | ~DDR_SIZE_MASK) + 1;
+		}
+	}
+	mvebu_mbus_dram_info.num_cs = cs;
+}
+
+static void __init
+mvebu_mbus_dove_setup_cpu_target(struct mvebu_mbus_state *mbus)
+{
+	int i;
+	int cs;
+
+	mvebu_mbus_dram_info.mbus_dram_target_id = TARGET_DDR;
+
+	for (i = 0, cs = 0; i < 2; i++) {
+		u32 map = readl(mbus->sdramwins_base + DOVE_DDR_BASE_CS_OFF(i));
+
+		/*
+		 * Chip select enabled?
+		 */
+		if (map & 1) {
+			struct mbus_dram_window *w;
+
+			w = &mvebu_mbus_dram_info.cs[cs++];
+			w->cs_index = i;
+			w->mbus_attr = 0; /* CS address decoding done inside */
+					  /* the DDR controller, no need to  */
+					  /* provide attributes */
+			w->base = map & 0xff800000;
+			w->size = 0x100000 << (((map & 0x000f0000) >> 16) - 4);
+		}
+	}
+
+	mvebu_mbus_dram_info.num_cs = cs;
+}
+
+static const struct mvebu_mbus_mapping armada_370_map[] = {
+	MAPDEF("bootrom",     1, 0xe0, MAPDEF_NOMASK),
+	MAPDEF("devbus-boot", 1, 0x2f, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs0",  1, 0x3e, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs1",  1, 0x3d, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs2",  1, 0x3b, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs3",  1, 0x37, MAPDEF_NOMASK),
+	MAPDEF("pcie0.0",     4, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.0",     8, 0xe0, MAPDEF_PCIMASK),
+	{},
+};
+
+static const struct mvebu_mbus_soc_data armada_370_mbus_data = {
+	.num_wins            = 20,
+	.num_remappable_wins = 8,
+	.win_cfg_offset      = armada_370_xp_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = armada_370_map,
+};
+
+static const struct mvebu_mbus_mapping armada_xp_map[] = {
+	MAPDEF("bootrom",     1, 0x1d, MAPDEF_NOMASK),
+	MAPDEF("devbus-boot", 1, 0x2f, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs0",  1, 0x3e, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs1",  1, 0x3d, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs2",  1, 0x3b, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs3",  1, 0x37, MAPDEF_NOMASK),
+	MAPDEF("pcie0.0",     4, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.1",     4, 0xd0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.2",     4, 0xb0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.3",     4, 0x70, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.0",     8, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.1",     8, 0xd0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.2",     8, 0xb0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.3",     8, 0x70, MAPDEF_PCIMASK),
+	MAPDEF("pcie2.0",     4, 0xf0, MAPDEF_PCIMASK),
+	MAPDEF("pcie3.0",     8, 0xf0, MAPDEF_PCIMASK),
+	{},
+};
+
+static const struct mvebu_mbus_soc_data armada_xp_mbus_data = {
+	.num_wins            = 20,
+	.num_remappable_wins = 8,
+	.win_cfg_offset      = armada_370_xp_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = armada_xp_map,
+};
+
+static const struct mvebu_mbus_mapping kirkwood_map[] = {
+	MAPDEF("pcie0.0", 4, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.0", 8, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("sram",    3, 0x01, MAPDEF_NOMASK),
+	MAPDEF("nand",    1, 0x2f, MAPDEF_NOMASK),
+	{},
+};
+
+static const struct mvebu_mbus_soc_data kirkwood_mbus_data = {
+	.num_wins            = 8,
+	.num_remappable_wins = 4,
+	.win_cfg_offset      = orion_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = kirkwood_map,
+};
+
+static const struct mvebu_mbus_mapping dove_map[] = {
+	MAPDEF("pcie0.0",    0x4, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.0",    0x8, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("cesa",       0x3, 0x01, MAPDEF_NOMASK),
+	MAPDEF("bootrom",    0x1, 0xfd, MAPDEF_NOMASK),
+	MAPDEF("scratchpad", 0xd, 0x0, MAPDEF_NOMASK),
+	{},
+};
+
+static const struct mvebu_mbus_soc_data dove_mbus_data = {
+	.num_wins            = 8,
+	.num_remappable_wins = 4,
+	.win_cfg_offset      = orion_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_dove_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_dove,
+	.map                 = dove_map,
+};
+
+static const struct mvebu_mbus_mapping orion5x_map[] = {
+	MAPDEF("pcie0.0",     4, 0x51, MAPDEF_ORIONPCIMASK),
+	MAPDEF("pci0.0",      3, 0x51, MAPDEF_ORIONPCIMASK),
+	MAPDEF("devbus-boot", 1, 0x0f, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs0",  1, 0x1e, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs1",  1, 0x1d, MAPDEF_NOMASK),
+	MAPDEF("devbus-cs2",  1, 0x1b, MAPDEF_NOMASK),
+	MAPDEF("sram",        0, 0x00, MAPDEF_NOMASK),
+	{},
+};
+
+/*
+ * Some variants of Orion5x have 4 remappable windows, some other have
+ * only two of them.
+ */
+static const struct mvebu_mbus_soc_data orion5x_4win_mbus_data = {
+	.num_wins            = 8,
+	.num_remappable_wins = 4,
+	.win_cfg_offset      = orion_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = orion5x_map,
+};
+
+static const struct mvebu_mbus_soc_data orion5x_2win_mbus_data = {
+	.num_wins            = 8,
+	.num_remappable_wins = 2,
+	.win_cfg_offset      = orion_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = orion5x_map,
+};
+
+static const struct mvebu_mbus_mapping mv78xx0_map[] = {
+	MAPDEF("pcie0.0", 4, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.1", 4, 0xd0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.2", 4, 0xb0, MAPDEF_PCIMASK),
+	MAPDEF("pcie0.3", 4, 0x70, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.0", 8, 0xe0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.1", 8, 0xd0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.2", 8, 0xb0, MAPDEF_PCIMASK),
+	MAPDEF("pcie1.3", 8, 0x70, MAPDEF_PCIMASK),
+	MAPDEF("pcie2.0", 4, 0xf0, MAPDEF_PCIMASK),
+	MAPDEF("pcie3.0", 8, 0xf0, MAPDEF_PCIMASK),
+	{},
+};
+
+static const struct mvebu_mbus_soc_data mv78xx0_mbus_data = {
+	.num_wins            = 14,
+	.num_remappable_wins = 8,
+	.win_cfg_offset      = mv78xx0_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+	.show_cpu_target     = mvebu_sdram_debug_show_orion,
+	.map                 = mv78xx0_map,
+};
+
+/*
+ * The driver doesn't yet have a DT binding because the details of
+ * this DT binding still need to be sorted out. However, as a
+ * preparation, we already use of_device_id to match a SoC description
+ * string against the SoC specific details of this driver.
+ */
+static const struct of_device_id of_mvebu_mbus_ids[] = {
+	{ .compatible = "marvell,armada370-mbus",
+	  .data = &armada_370_mbus_data, },
+	{ .compatible = "marvell,armadaxp-mbus",
+	  .data = &armada_xp_mbus_data, },
+	{ .compatible = "marvell,kirkwood-mbus",
+	  .data = &kirkwood_mbus_data, },
+	{ .compatible = "marvell,dove-mbus",
+	  .data = &dove_mbus_data, },
+	{ .compatible = "marvell,orion5x-88f5281-mbus",
+	  .data = &orion5x_4win_mbus_data, },
+	{ .compatible = "marvell,orion5x-88f5182-mbus",
+	  .data = &orion5x_2win_mbus_data, },
+	{ .compatible = "marvell,orion5x-88f5181-mbus",
+	  .data = &orion5x_2win_mbus_data, },
+	{ .compatible = "marvell,orion5x-88f6183-mbus",
+	  .data = &orion5x_4win_mbus_data, },
+	{ .compatible = "marvell,mv78xx0-mbus",
+	  .data = &mv78xx0_mbus_data, },
+	{ },
+};
+
+/*
+ * Public API of the driver
+ */
+int mvebu_mbus_add_window_remap_flags(const char *devname, phys_addr_t base,
+				      size_t size, phys_addr_t remap,
+				      unsigned int flags)
+{
+	struct mvebu_mbus_state *s = &mbus_state;
+	u8 target, attr;
+	int i;
+
+	if (!s->soc->map)
+		return -ENODEV;
+
+	for (i = 0; s->soc->map[i].name; i++)
+		if (!strcmp(s->soc->map[i].name, devname))
+			break;
+
+	if (!s->soc->map[i].name) {
+		pr_err("mvebu-mbus: unknown device '%s'\n", devname);
+		return -ENODEV;
+	}
+
+	target = s->soc->map[i].target;
+	attr   = s->soc->map[i].attr;
+
+	if (flags == MVEBU_MBUS_PCI_MEM)
+		attr |= 0x8;
+	else if (flags == MVEBU_MBUS_PCI_WA)
+		attr |= 0x28;
+
+	if (!mvebu_mbus_window_conflicts(s, base, size, target, attr)) {
+		pr_err("mvebu-mbus: cannot add window '%s', conflicts with another window\n",
+		       devname);
+		return -EINVAL;
+	}
+
+	return mvebu_mbus_alloc_window(s, base, size, remap, target, attr);
+
+}
+
+int mvebu_mbus_add_window(const char *devname, phys_addr_t base, size_t size)
+{
+	return mvebu_mbus_add_window_remap_flags(devname, base, size,
+						 MVEBU_MBUS_NO_REMAP, 0);
+}
+
+int mvebu_mbus_del_window(phys_addr_t base, size_t size)
+{
+	int win;
+
+	win = mvebu_mbus_find_window(&mbus_state, base, size);
+	if (win < 0)
+		return win;
+
+	mvebu_mbus_disable_window(&mbus_state, win);
+	return 0;
+}
+
+static __init int mvebu_mbus_debugfs_init(void)
+{
+	struct mvebu_mbus_state *s = &mbus_state;
+
+	/*
+	 * If no base has been initialized, doesn't make sense to
+	 * register the debugfs entries. We may be on a multiplatform
+	 * kernel that isn't running a Marvell EBU SoC.
+	 */
+	if (!s->mbuswins_base)
+		return 0;
+
+	s->debugfs_root = debugfs_create_dir("mvebu-mbus", NULL);
+	if (s->debugfs_root) {
+		s->debugfs_sdram = debugfs_create_file("sdram", S_IRUGO,
+						       s->debugfs_root, NULL,
+						       &mvebu_sdram_debug_fops);
+		s->debugfs_devs = debugfs_create_file("devices", S_IRUGO,
+						      s->debugfs_root, NULL,
+						      &mvebu_devs_debug_fops);
+	}
+
+	return 0;
+}
+fs_initcall(mvebu_mbus_debugfs_init);
+
+int __init mvebu_mbus_init(const char *soc, phys_addr_t mbuswins_phys_base,
+			   size_t mbuswins_size,
+			   phys_addr_t sdramwins_phys_base,
+			   size_t sdramwins_size)
+{
+	struct mvebu_mbus_state *mbus = &mbus_state;
+	const struct of_device_id *of_id;
+	int win;
+
+	for (of_id = of_mvebu_mbus_ids; of_id->compatible; of_id++)
+		if (!strcmp(of_id->compatible, soc))
+			break;
+
+	if (!of_id->compatible) {
+		pr_err("mvebu-mbus: could not find a matching SoC family\n");
+		return -ENODEV;
+	}
+
+	mbus->soc = of_id->data;
+
+	mbus->mbuswins_base = ioremap(mbuswins_phys_base, mbuswins_size);
+	if (!mbus->mbuswins_base)
+		return -ENOMEM;
+
+	mbus->sdramwins_base = ioremap(sdramwins_phys_base, sdramwins_size);
+	if (!mbus->sdramwins_base) {
+		iounmap(mbus_state.mbuswins_base);
+		return -ENOMEM;
+	}
+
+	for (win = 0; win < mbus->soc->num_wins; win++)
+		mvebu_mbus_disable_window(mbus, win);
+
+	mbus->soc->setup_cpu_target(mbus);
+
+	return 0;
+}

include/linux/mbus.h

@@ -32,6 +32,17 @@ struct mbus_dram_target_info
 	} cs[4];
 };
 
+/* Flags for PCI/PCIe address decoding regions */
+#define MVEBU_MBUS_PCI_IO  0x1
+#define MVEBU_MBUS_PCI_MEM 0x2
+#define MVEBU_MBUS_PCI_WA  0x3
+
+/*
+ * Magic value that explicits that we don't need a remapping-capable
+ * address decoding window.
+ */
+#define MVEBU_MBUS_NO_REMAP (0xffffffff)
+
 /*
  * The Marvell mbus is to be found only on SOCs from the Orion family
  * at the moment.  Provide a dummy stub for other architectures.
@@ -44,4 +55,15 @@ static inline const struct mbus_dram_target_info *mv_mbus_dram_info(void)
 	return NULL;
 }
 #endif
-#endif
+
+int mvebu_mbus_add_window_remap_flags(const char *devname, phys_addr_t base,
+				      size_t size, phys_addr_t remap,
+				      unsigned int flags);
+int mvebu_mbus_add_window(const char *devname, phys_addr_t base,
+			  size_t size);
+int mvebu_mbus_del_window(phys_addr_t base, size_t size);
+int mvebu_mbus_init(const char *soc, phys_addr_t mbus_phys_base,
+		    size_t mbus_size, phys_addr_t sdram_phys_base,
+		    size_t sdram_size);
+
+#endif /* __LINUX_MBUS_H */