--- /dev/null
+UniPhier System Bus
+
+The UniPhier System Bus is an external bus that connects on-board devices to
+the UniPhier SoC. It is a simple (semi-)parallel bus with address, data, and
+some control signals. It supports up to 8 banks (chip selects).
+
+Before any access to the bus, the bus controller must be configured; the bus
+controller registers provide the control for the translation from the offset
+within each bank to the CPU-viewed address. The needed setup includes the base
+address, the size of each bank. Optionally, some timing parameters can be
+optimized for faster bus access.
+
+Required properties:
+- compatible: should be "socionext,uniphier-system-bus".
+- reg: offset and length of the register set for the bus controller device.
+- #address-cells: should be 2. The first cell is the bank number (chip select).
+ The second cell is the address offset within the bank.
+- #size-cells: should be 1.
+- ranges: should provide a proper address translation from the System Bus to
+ the parent bus.
+
+Note:
+The address region(s) that can be assigned for the System Bus is implementation
+defined. Some SoCs can use 0x00000000-0x0fffffff and 0x40000000-0x4fffffff,
+while other SoCs can only use 0x40000000-0x4fffffff. There might be additional
+limitations depending on SoCs and the boot mode. The address translation is
+arbitrary as long as the banks are assigned in the supported address space with
+the required alignment and they do not overlap one another.
+For example, it is possible to map:
+ bank 0 to 0x42000000-0x43ffffff, bank 5 to 0x46000000-0x46ffffff
+It is also possible to map:
+ bank 0 to 0x48000000-0x49ffffff, bank 5 to 0x44000000-0x44ffffff
+There is no reason to stick to a particular translation mapping, but the
+"ranges" property should provide a "reasonable" default that is known to work.
+The software should initialize the bus controller according to it.
+
+Example:
+
+ system-bus {
+ compatible = "socionext,uniphier-system-bus";
+ reg = <0x58c00000 0x400>;
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges = <1 0x00000000 0x42000000 0x02000000
+ 5 0x00000000 0x46000000 0x01000000>;
+
+ ethernet@1,01f00000 {
+ compatible = "smsc,lan9115";
+ reg = <1 0x01f00000 0x1000>;
+ interrupts = <0 48 4>
+ phy-mode = "mii";
+ };
+
+ uart@5,00200000 {
+ compatible = "ns16550a";
+ reg = <5 0x00200000 0x20>;
+ interrupts = <0 49 4>
+ clock-frequency = <12288000>;
+ };
+ };
+
+In this example,
+ - the Ethernet device is connected at the offset 0x01f00000 of CS1 and
+ mapped to 0x43f00000 of the parent bus.
+ - the UART device is connected at the offset 0x00200000 of CS5 and
+ mapped to 0x46200000 of the parent bus.
--- /dev/null
+/*
+ * 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");
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff