1 files changed, 281 insertions, 0 deletions
diff --git a/drivers/bus/uniphier-system-bus.c b/drivers/bus/uniphier-system-bus.c
new file mode 100644
index 000000000000..834a2aeaf27a
--- /dev/null
+++ b/drivers/bus/uniphier-system-bus.c
@@ -0,0 +1,281 @@
+/*
+ * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/io.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+/* System Bus Controller registers */
+#define UNIPHIER_SBC_BASE	0x100	/* base address of bank0 space */
+#define    UNIPHIER_SBC_BASE_BE		BIT(0)	/* bank_enable */
+#define UNIPHIER_SBC_CTRL0	0x200	/* timing parameter 0 of bank0 */
+#define UNIPHIER_SBC_CTRL1	0x204	/* timing parameter 1 of bank0 */
+#define UNIPHIER_SBC_CTRL2	0x208	/* timing parameter 2 of bank0 */
+#define UNIPHIER_SBC_CTRL3	0x20c	/* timing parameter 3 of bank0 */
+#define UNIPHIER_SBC_CTRL4	0x300	/* timing parameter 4 of bank0 */
+
+#define UNIPHIER_SBC_STRIDE	0x10	/* register stride to next bank */
+#define UNIPHIER_SBC_NR_BANKS	8	/* number of banks (chip select) */
+#define UNIPHIER_SBC_BASE_DUMMY	0xffffffff	/* data to squash bank 0, 1 */
+
+struct uniphier_system_bus_bank {
+	u32 base;
+	u32 end;
+};
+
+struct uniphier_system_bus_priv {
+	struct device *dev;
+	void __iomem *membase;
+	struct uniphier_system_bus_bank bank[UNIPHIER_SBC_NR_BANKS];
+};
+
+static int uniphier_system_bus_add_bank(struct uniphier_system_bus_priv *priv,
+					int bank, u32 addr, u64 paddr, u32 size)
+{
+	u64 end, mask;
+
+	dev_dbg(priv->dev,
+		"range found: bank = %d, addr = %08x, paddr = %08llx, size = %08x\n",
+		bank, addr, paddr, size);
+
+	if (bank >= ARRAY_SIZE(priv->bank)) {
+		dev_err(priv->dev, "unsupported bank number %d\n", bank);
+		return -EINVAL;
+	}
+
+	if (priv->bank[bank].base || priv->bank[bank].end) {
+		dev_err(priv->dev,
+			"range for bank %d has already been specified\n", bank);
+		return -EINVAL;
+	}
+
+	if (paddr > U32_MAX) {
+		dev_err(priv->dev, "base address %llx is too high\n", paddr);
+		return -EINVAL;
+	}
+
+	end = paddr + size;
+
+	if (addr > paddr) {
+		dev_err(priv->dev,
+			"base %08x cannot be mapped to %08llx of parent\n",
+			addr, paddr);
+		return -EINVAL;
+	}
+	paddr -= addr;
+
+	paddr = round_down(paddr, 0x00020000);
+	end = round_up(end, 0x00020000);
+
+	if (end > U32_MAX) {
+		dev_err(priv->dev, "end address %08llx is too high\n", end);
+		return -EINVAL;
+	}
+	mask = paddr ^ (end - 1);
+	mask = roundup_pow_of_two(mask);
+
+	paddr = round_down(paddr, mask);
+	end = round_up(end, mask);
+
+	priv->bank[bank].base = paddr;
+	priv->bank[bank].end = end;
+
+	dev_dbg(priv->dev, "range added: bank = %d, addr = %08x, end = %08x\n",
+		bank, priv->bank[bank].base, priv->bank[bank].end);
+
+	return 0;
+}
+
+static int uniphier_system_bus_check_overlap(
+				const struct uniphier_system_bus_priv *priv)
+{
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
+		for (j = i + 1; j < ARRAY_SIZE(priv->bank); j++) {
+			if (priv->bank[i].end > priv->bank[j].base ||
+			    priv->bank[i].base < priv->bank[j].end) {
+				dev_err(priv->dev,
+					"region overlap between bank%d and bank%d\n",
+					i, j);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static void uniphier_system_bus_check_boot_swap(
+					struct uniphier_system_bus_priv *priv)
+{
+	void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
+	int is_swapped;
+
+	is_swapped = !(readl(base_reg) & UNIPHIER_SBC_BASE_BE);
+
+	dev_dbg(priv->dev, "Boot Swap: %s\n", is_swapped ? "on" : "off");
+
+	/*
+	 * If BOOT_SWAP was asserted on power-on-reset, the CS0 and CS1 are
+	 * swapped.  In this case, bank0 and bank1 should be swapped as well.
+	 */
+	if (is_swapped)
+		swap(priv->bank[0], priv->bank[1]);
+}
+
+static void uniphier_system_bus_set_reg(
+				const struct uniphier_system_bus_priv *priv)
+{
+	void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
+	u32 base, end, mask, val;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
+		base = priv->bank[i].base;
+		end = priv->bank[i].end;
+
+		if (base == end) {
+			/*
+			 * If SBC_BASE0 or SBC_BASE1 is set to zero, the access
+			 * to anywhere in the system bus space is routed to
+			 * bank 0 (if boot swap if off) or bank 1 (if boot swap
+			 * if on).  It means that CPUs cannot get access to
+			 * bank 2 or later.  In other words, bank 0/1 cannot
+			 * be disabled even if its bank_enable bits is cleared.
+			 * This seems odd, but it is how this hardware goes.
+			 * As a workaround, dummy data (0xffffffff) should be
+			 * set when the bank 0/1 is unused.  As for bank 2 and
+			 * later, they can be simply disable by clearing the
+			 * bank_enable bit.
+			 */
+			if (i < 2)
+				val = UNIPHIER_SBC_BASE_DUMMY;
+			else
+				val = 0;
+		} else {
+			mask = base ^ (end - 1);
+
+			val = base & 0xfffe0000;
+			val |= (~mask >> 16) & 0xfffe;
+			val |= UNIPHIER_SBC_BASE_BE;
+		}
+		dev_dbg(priv->dev, "SBC_BASE[%d] = 0x%08x\n", i, val);
+
+		writel(val, base_reg + UNIPHIER_SBC_STRIDE * i);
+	}
+}
+
+static int uniphier_system_bus_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct uniphier_system_bus_priv *priv;
+	struct resource *regs;
+	const __be32 *ranges;
+	u32 cells, addr, size;
+	u64 paddr;
+	int pna, bank, rlen, rone, ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->membase = devm_ioremap_resource(dev, regs);
+	if (IS_ERR(priv->membase))
+		return PTR_ERR(priv->membase);
+
+	priv->dev = dev;
+
+	pna = of_n_addr_cells(dev->of_node);
+
+	ret = of_property_read_u32(dev->of_node, "#address-cells", &cells);
+	if (ret) {
+		dev_err(dev, "failed to get #address-cells\n");
+		return ret;
+	}
+	if (cells != 2) {
+		dev_err(dev, "#address-cells must be 2\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32(dev->of_node, "#size-cells", &cells);
+	if (ret) {
+		dev_err(dev, "failed to get #size-cells\n");
+		return ret;
+	}
+	if (cells != 1) {
+		dev_err(dev, "#size-cells must be 1\n");
+		return -EINVAL;
+	}
+
+	ranges = of_get_property(dev->of_node, "ranges", &rlen);
+	if (!ranges) {
+		dev_err(dev, "failed to get ranges property\n");
+		return -ENOENT;
+	}
+
+	rlen /= sizeof(*ranges);
+	rone = pna + 2;
+
+	for (; rlen >= rone; rlen -= rone) {
+		bank = be32_to_cpup(ranges++);
+		addr = be32_to_cpup(ranges++);
+		paddr = of_translate_address(dev->of_node, ranges);
+		if (paddr == OF_BAD_ADDR)
+			return -EINVAL;
+		ranges += pna;
+		size = be32_to_cpup(ranges++);
+
+		ret = uniphier_system_bus_add_bank(priv, bank, addr,
+						   paddr, size);
+		if (ret)
+			return ret;
+	}
+
+	ret = uniphier_system_bus_check_overlap(priv);
+	if (ret)
+		return ret;
+
+	uniphier_system_bus_check_boot_swap(priv);
+
+	uniphier_system_bus_set_reg(priv);
+
+	/* Now, the bus is configured.  Populate platform_devices below it */
+	return of_platform_populate(dev->of_node, of_default_bus_match_table,
+				    NULL, dev);
+}
+
+static const struct of_device_id uniphier_system_bus_match[] = {
+	{ .compatible = "socionext,uniphier-system-bus" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, uniphier_system_bus_match);
+
+static struct platform_driver uniphier_system_bus_driver = {
+	.probe		= uniphier_system_bus_probe,
+	.driver = {
+		.name	= "uniphier-system-bus",
+		.of_match_table = uniphier_system_bus_match,
+	},
+};
+module_platform_driver(uniphier_system_bus_driver);
+
+MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
+MODULE_DESCRIPTION("UniPhier System Bus driver");
+MODULE_LICENSE("GPL");