arm: mvebu: Add common mbus functions to use on Marvell SoCs

These mbus functions are ported from Barebox. The Barebox version is
ported from Linux. These functions will be first used by the upcoming
Armada XP support. Later other Marvell SoC's will be adopted to use
these functions as well (Kirkwood, Orion).

Signed-off-by: Stefan Roese <sr@denx.de>
Tested-by: Luka Perkov <luka@openwrt.org>

2 files changed, 472 insertions, 0 deletions

diff --git a/arch/arm/mvebu-common/Makefile b/arch/arm/mvebu-common/Makefile
index 4d20d2c..391a125 100644
--- a/arch/arm/mvebu-common/Makefile
+++ b/arch/arm/mvebu-common/Makefile
@@ -7,4 +7,5 @@
 #
 
 obj-y	= dram.o
+obj-$(CONFIG_ARMADA_XP) += mbus.o
 obj-y	+= timer.o
diff --git a/arch/arm/mvebu-common/mbus.c b/arch/arm/mvebu-common/mbus.c
new file mode 100644
index 0000000..05c9ef2
--- /dev/null
+++ b/arch/arm/mvebu-common/mbus.c
@@ -0,0 +1,471 @@
+/*
+ * Address map functions for Marvell EBU SoCs (Kirkwood, Armada
+ * 370/XP, Dove, Orion5x and MV78xx0)
+ *
+ * Ported from the Barebox version to U-Boot by:
+ * Stefan Roese <sr@denx.de>
+ *
+ * The Barebox version is:
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ *
+ * based on mbus driver from Linux
+ *   (C) Copyright 2008 Marvell Semiconductor
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ *
+ * 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 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_by_id(),
+ *   mvebu_mbus_add_window_remap_by_id() and
+ *   mvebu_mbus_del_window().
+ */
+
+#include <common.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/soc.h>
+#include <linux/mbus.h>
+
+#define BIT(nr)			(1UL << (nr))
+
+/* 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_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);
+};
+
+struct mvebu_mbus_state mbus_state
+	__attribute__ ((section(".data")));
+static struct mbus_dram_target_info mbus_dram_info
+	__attribute__ ((section(".data")));
+
+/*
+ * 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;
+}
+
+/*
+ * SoC-specific functions and definitions
+ */
+
+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 orion5x_mbus_win_offset(int win)
+{
+	return win << 4;
+}
+
+static void mvebu_mbus_default_setup_cpu_target(struct mvebu_mbus_state *mbus)
+{
+	int i;
+	int cs;
+
+	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 = &mbus_dram_info.cs[cs++];
+			w->cs_index = i;
+			w->mbus_attr = 0xf & ~(1 << i);
+#if defined(CONFIG_ARMADA_XP)
+			w->mbus_attr |= ATTR_HW_COHERENCY;
+#endif
+			w->base = base & DDR_BASE_CS_LOW_MASK;
+			w->size = (size | ~DDR_SIZE_MASK) + 1;
+		}
+	}
+	mbus_dram_info.num_cs = cs;
+}
+
+static const struct mvebu_mbus_soc_data
+armada_370_xp_mbus_data __maybe_unused = {
+	.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,
+};
+
+static const struct mvebu_mbus_soc_data
+kirkwood_mbus_data __maybe_unused = {
+	.num_wins            = 8,
+	.num_remappable_wins = 4,
+	.win_cfg_offset      = orion5x_mbus_win_offset,
+	.setup_cpu_target    = mvebu_mbus_default_setup_cpu_target,
+};
+
+/*
+ * Public API of the driver
+ */
+const struct mbus_dram_target_info *mvebu_mbus_dram_info(void)
+{
+	return &mbus_dram_info;
+}
+
+int mvebu_mbus_add_window_remap_by_id(unsigned int target,
+				      unsigned int attribute,
+				      phys_addr_t base, size_t size,
+				      phys_addr_t remap)
+{
+	struct mvebu_mbus_state *s = &mbus_state;
+
+	if (!mvebu_mbus_window_conflicts(s, base, size, target, attribute)) {
+		printf("Cannot add window '%x:%x', conflicts with another window\n",
+		       target, attribute);
+		return -EINVAL;
+	}
+
+	return mvebu_mbus_alloc_window(s, base, size, remap, target, attribute);
+}
+
+int mvebu_mbus_add_window_by_id(unsigned int target, unsigned int attribute,
+				phys_addr_t base, size_t size)
+{
+	return mvebu_mbus_add_window_remap_by_id(target, attribute, base,
+						 size, MVEBU_MBUS_NO_REMAP);
+}
+
+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;
+}
+
+int mbus_dt_setup_win(struct mvebu_mbus_state *mbus,
+		      u32 base, u32 size, u8 target, u8 attr)
+{
+	if (!mvebu_mbus_window_conflicts(mbus, base, size, target, attr)) {
+		printf("Cannot add window '%04x:%04x', conflicts with another window\n",
+		       target, attr);
+		return -EBUSY;
+	}
+
+	/*
+	 * In U-Boot we first try to add the mbus window to the remap windows.
+	 * If this fails, lets try to add the windows to the non-remap windows.
+	 */
+	if (mvebu_mbus_alloc_window(mbus, base, size, base, target, attr)) {
+		if (mvebu_mbus_alloc_window(mbus, base, size,
+					    MVEBU_MBUS_NO_REMAP, target, attr))
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int mvebu_mbus_probe(struct mbus_win windows[], int count)
+{
+	int win;
+	int ret;
+	int i;
+
+#if defined(CONFIG_KIRKWOOD)
+	mbus_state.soc = &kirkwood_mbus_data;
+#endif
+#if defined(CONFIG_ARMADA_XP)
+	mbus_state.soc = &armada_370_xp_mbus_data;
+#endif
+
+	mbus_state.mbuswins_base = (void __iomem *)MVEBU_CPU_WIN_BASE;
+	mbus_state.sdramwins_base = (void __iomem *)MVEBU_SDRAM_BASE;
+
+	for (win = 0; win < mbus_state.soc->num_wins; win++)
+		mvebu_mbus_disable_window(&mbus_state, win);
+
+	mbus_state.soc->setup_cpu_target(&mbus_state);
+
+	/* Setup statically declared windows in the DT */
+	for (i = 0; i < count; i++) {
+		u32 base, size;
+		u8 target, attr;
+
+		target = windows[i].target;
+		attr = windows[i].attr;
+		base = windows[i].base;
+		size = windows[i].size;
+		ret = mbus_dt_setup_win(&mbus_state, base, size, target, attr);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}