--- /dev/null
+Device tree bindings for MVEBU Device Bus controllers
+
+The Device Bus controller available in some Marvell's SoC allows to control
+different types of standard memory and I/O devices such as NOR, NAND, and FPGA.
+The actual devices are instantiated from the child nodes of a Device Bus node.
+
+Required properties:
+
+ - compatible: Currently only Armada 370/XP SoC are supported,
+ with this compatible string:
+
+ marvell,mvebu-devbus
+
+ - reg: A resource specifier for the register space.
+ This is the base address of a chip select within
+ the controller's register space.
+ (see the example below)
+
+ - #address-cells: Must be set to 1
+ - #size-cells: Must be set to 1
+ - ranges: Must be set up to reflect the memory layout with four
+ integer values for each chip-select line in use:
+ 0 <physical address of mapping> <size>
+
+Mandatory timing properties for child nodes:
+
+Read parameters:
+
+ - devbus,turn-off-ps: Defines the time during which the controller does not
+ drive the AD bus after the completion of a device read.
+ This prevents contentions on the Device Bus after a read
+ cycle from a slow device.
+
+ - devbus,bus-width: Defines the bus width (e.g. <16>)
+
+ - devbus,badr-skew-ps: Defines the time delay from from A[2:0] toggle,
+ to read data sample. This parameter is useful for
+ synchronous pipelined devices, where the address
+ precedes the read data by one or two cycles.
+
+ - devbus,acc-first-ps: Defines the time delay from the negation of
+ ALE[0] to the cycle that the first read data is sampled
+ by the controller.
+
+ - devbus,acc-next-ps: Defines the time delay between the cycle that
+ samples data N and the cycle that samples data N+1
+ (in burst accesses).
+
+ - devbus,rd-setup-ps: Defines the time delay between DEV_CSn assertion to
+ DEV_OEn assertion. If set to 0 (default),
+ DEV_OEn and DEV_CSn are asserted at the same cycle.
+ This parameter has no affect on <acc-first-ps> parameter
+ (no affect on first data sample). Set <rd-setup-ps>
+ to a value smaller than <acc-first-ps>.
+
+ - devbus,rd-hold-ps: Defines the time between the last data sample to the
+ de-assertion of DEV_CSn. If set to 0 (default),
+ DEV_OEn and DEV_CSn are de-asserted at the same cycle
+ (the cycle of the last data sample).
+ This parameter has no affect on DEV_OEn de-assertion.
+ DEV_OEn is always de-asserted the next cycle after
+ last data sampled. Also this parameter has no
+ affect on <turn-off-ps> parameter.
+ Set <rd-hold-ps> to a value smaller than <turn-off-ps>.
+
+Write parameters:
+
+ - devbus,ale-wr-ps: Defines the time delay from the ALE[0] negation cycle
+ to the DEV_WEn assertion.
+
+ - devbus,wr-low-ps: Defines the time during which DEV_WEn is active.
+ A[2:0] and Data are kept valid as long as DEV_WEn
+ is active. This parameter defines the setup time of
+ address and data to DEV_WEn rise.
+
+ - devbus,wr-high-ps: Defines the time during which DEV_WEn is kept
+ inactive (high) between data beats of a burst write.
+ DEV_A[2:0] and Data are kept valid (do not toggle) for
+ <wr-high-ps> - <tick> ps.
+ This parameter defines the hold time of address and
+ data after DEV_WEn rise.
+
+ - devbus,sync-enable: Synchronous device enable.
+ 1: True
+ 0: False
+
+An example for an Armada XP GP board, with a 16 MiB NOR device as child
+is showed below. Note that the Device Bus driver is in charge of allocating
+the mbus address decoding window for each of its child devices.
+The window is created using the chip select specified in the child
+device node together with the base address and size specified in the ranges
+property. For instance, in the example below the allocated decoding window
+will start at base address 0xf0000000, with a size 0x1000000 (16 MiB)
+for chip select 0 (a.k.a DEV_BOOTCS).
+
+This address window handling is done in this mvebu-devbus only as a temporary
+solution. It will be removed when the support for mbus device tree binding is
+added.
+
+The reg property implicitly specifies the chip select as this:
+
+ 0x10400: DEV_BOOTCS
+ 0x10408: DEV_CS0
+ 0x10410: DEV_CS1
+ 0x10418: DEV_CS2
+ 0x10420: DEV_CS3
+
+Example:
+
+ devbus-bootcs@d0010400 {
+ status = "okay";
+ ranges = <0 0xf0000000 0x1000000>; /* @addr 0xf0000000, size 0x1000000 */
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ /* Device Bus parameters are required */
+
+ /* Read parameters */
+ devbus,bus-width = <8>;
+ devbus,turn-off-ps = <60000>;
+ devbus,badr-skew-ps = <0>;
+ devbus,acc-first-ps = <124000>;
+ devbus,acc-next-ps = <248000>;
+ devbus,rd-setup-ps = <0>;
+ devbus,rd-hold-ps = <0>;
+
+ /* Write parameters */
+ devbus,sync-enable = <0>;
+ devbus,wr-high-ps = <60000>;
+ devbus,wr-low-ps = <60000>;
+ devbus,ale-wr-ps = <60000>;
+
+ flash@0 {
+ compatible = "cfi-flash";
+
+ /* 16 MiB */
+ reg = <0 0x1000000>;
+ bank-width = <2>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+
+ /*
+ * We split the 16 MiB in two partitions,
+ * just as an example.
+ */
+ partition@0 {
+ label = "First";
+ reg = <0 0x800000>;
+ };
+
+ partition@800000 {
+ label = "Second";
+ reg = <0x800000 0x800000>;
+ };
+ };
+ };
--- /dev/null
+/*
+ * Marvell EBU SoC Device Bus Controller
+ * (memory controller for NOR/NAND/SRAM/FPGA devices)
+ *
+ * Copyright (C) 2013 Marvell
+ *
+ * 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 version 2 of the License.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/mbus.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+
+/* Register definitions */
+#define DEV_WIDTH_BIT 30
+#define BADR_SKEW_BIT 28
+#define RD_HOLD_BIT 23
+#define ACC_NEXT_BIT 17
+#define RD_SETUP_BIT 12
+#define ACC_FIRST_BIT 6
+
+#define SYNC_ENABLE_BIT 24
+#define WR_HIGH_BIT 16
+#define WR_LOW_BIT 8
+
+#define READ_PARAM_OFFSET 0x0
+#define WRITE_PARAM_OFFSET 0x4
+
+static const char * const devbus_wins[] = {
+ "devbus-boot",
+ "devbus-cs0",
+ "devbus-cs1",
+ "devbus-cs2",
+ "devbus-cs3",
+};
+
+struct devbus_read_params {
+ u32 bus_width;
+ u32 badr_skew;
+ u32 turn_off;
+ u32 acc_first;
+ u32 acc_next;
+ u32 rd_setup;
+ u32 rd_hold;
+};
+
+struct devbus_write_params {
+ u32 sync_enable;
+ u32 wr_high;
+ u32 wr_low;
+ u32 ale_wr;
+};
+
+struct devbus {
+ struct device *dev;
+ void __iomem *base;
+ unsigned long tick_ps;
+};
+
+static int get_timing_param_ps(struct devbus *devbus,
+ struct device_node *node,
+ const char *name,
+ u32 *ticks)
+{
+ u32 time_ps;
+ int err;
+
+ err = of_property_read_u32(node, name, &time_ps);
+ if (err < 0) {
+ dev_err(devbus->dev, "%s has no '%s' property\n",
+ name, node->full_name);
+ return err;
+ }
+
+ *ticks = (time_ps + devbus->tick_ps - 1) / devbus->tick_ps;
+
+ dev_dbg(devbus->dev, "%s: %u ps -> 0x%x\n",
+ name, time_ps, *ticks);
+ return 0;
+}
+
+static int devbus_set_timing_params(struct devbus *devbus,
+ struct device_node *node)
+{
+ struct devbus_read_params r;
+ struct devbus_write_params w;
+ u32 value;
+ int err;
+
+ dev_dbg(devbus->dev, "Setting timing parameter, tick is %lu ps\n",
+ devbus->tick_ps);
+
+ /* Get read timings */
+ err = of_property_read_u32(node, "devbus,bus-width", &r.bus_width);
+ if (err < 0) {
+ dev_err(devbus->dev,
+ "%s has no 'devbus,bus-width' property\n",
+ node->full_name);
+ return err;
+ }
+ /* Convert bit width to byte width */
+ r.bus_width /= 8;
+
+ err = get_timing_param_ps(devbus, node, "devbus,badr-skew-ps",
+ &r.badr_skew);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,turn-off-ps",
+ &r.turn_off);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,acc-first-ps",
+ &r.acc_first);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,acc-next-ps",
+ &r.acc_next);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,rd-setup-ps",
+ &r.rd_setup);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,rd-hold-ps",
+ &r.rd_hold);
+ if (err < 0)
+ return err;
+
+ /* Get write timings */
+ err = of_property_read_u32(node, "devbus,sync-enable",
+ &w.sync_enable);
+ if (err < 0) {
+ dev_err(devbus->dev,
+ "%s has no 'devbus,sync-enable' property\n",
+ node->full_name);
+ return err;
+ }
+
+ err = get_timing_param_ps(devbus, node, "devbus,ale-wr-ps",
+ &w.ale_wr);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,wr-low-ps",
+ &w.wr_low);
+ if (err < 0)
+ return err;
+
+ err = get_timing_param_ps(devbus, node, "devbus,wr-high-ps",
+ &w.wr_high);
+ if (err < 0)
+ return err;
+
+ /* Set read timings */
+ value = r.bus_width << DEV_WIDTH_BIT |
+ r.badr_skew << BADR_SKEW_BIT |
+ r.rd_hold << RD_HOLD_BIT |
+ r.acc_next << ACC_NEXT_BIT |
+ r.rd_setup << RD_SETUP_BIT |
+ r.acc_first << ACC_FIRST_BIT |
+ r.turn_off;
+
+ dev_dbg(devbus->dev, "read parameters register 0x%p = 0x%x\n",
+ devbus->base + READ_PARAM_OFFSET,
+ value);
+
+ writel(value, devbus->base + READ_PARAM_OFFSET);
+
+ /* Set write timings */
+ value = w.sync_enable << SYNC_ENABLE_BIT |
+ w.wr_low << WR_LOW_BIT |
+ w.wr_high << WR_HIGH_BIT |
+ w.ale_wr;
+
+ dev_dbg(devbus->dev, "write parameters register: 0x%p = 0x%x\n",
+ devbus->base + WRITE_PARAM_OFFSET,
+ value);
+
+ writel(value, devbus->base + WRITE_PARAM_OFFSET);
+
+ return 0;
+}
+
+static int mvebu_devbus_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *node = pdev->dev.of_node;
+ struct device_node *parent;
+ struct devbus *devbus;
+ struct resource *res;
+ struct clk *clk;
+ unsigned long rate;
+ const __be32 *ranges;
+ int err, cs;
+ int addr_cells, p_addr_cells, size_cells;
+ int ranges_len, tuple_len;
+ u32 base, size;
+
+ devbus = devm_kzalloc(&pdev->dev, sizeof(struct devbus), GFP_KERNEL);
+ if (!devbus)
+ return -ENOMEM;
+
+ devbus->dev = dev;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ devbus->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(devbus->base))
+ return PTR_ERR(devbus->base);
+
+ clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+ clk_prepare_enable(clk);
+
+ /*
+ * Obtain clock period in picoseconds,
+ * we need this in order to convert timing
+ * parameters from cycles to picoseconds.
+ */
+ rate = clk_get_rate(clk) / 1000;
+ devbus->tick_ps = 1000000000 / rate;
+
+ /* Read the device tree node and set the new timing parameters */
+ err = devbus_set_timing_params(devbus, node);
+ if (err < 0)
+ return err;
+
+ /*
+ * Allocate an address window for this device.
+ * If the device probing fails, then we won't be able to
+ * remove the allocated address decoding window.
+ *
+ * FIXME: This is only a temporary hack! We need to do this here
+ * because we still don't have device tree bindings for mbus.
+ * Once that support is added, we will declare these address windows
+ * statically in the device tree, and remove the window configuration
+ * from here.
+ */
+
+ /*
+ * Get the CS to choose the window string.
+ * This is a bit hacky, but it will be removed once the
+ * address windows are declared in the device tree.
+ */
+ cs = (((unsigned long)devbus->base) % 0x400) / 8;
+
+ /*
+ * Parse 'ranges' property to obtain a (base,size) window tuple.
+ * This will be removed once the address windows
+ * are declared in the device tree.
+ */
+ parent = of_get_parent(node);
+ if (!parent)
+ return -EINVAL;
+
+ p_addr_cells = of_n_addr_cells(parent);
+ of_node_put(parent);
+
+ addr_cells = of_n_addr_cells(node);
+ size_cells = of_n_size_cells(node);
+ tuple_len = (p_addr_cells + addr_cells + size_cells) * sizeof(__be32);
+
+ ranges = of_get_property(node, "ranges", &ranges_len);
+ if (ranges == NULL || ranges_len != tuple_len)
+ return -EINVAL;
+
+ base = of_translate_address(node, ranges + addr_cells);
+ if (base == OF_BAD_ADDR)
+ return -EINVAL;
+ size = of_read_number(ranges + addr_cells + p_addr_cells, size_cells);
+
+ /*
+ * Create an mbus address windows.
+ * FIXME: Remove this, together with the above code, once the
+ * address windows are declared in the device tree.
+ */
+ err = mvebu_mbus_add_window(devbus_wins[cs], base, size);
+ if (err < 0)
+ return err;
+
+ /*
+ * We need to create a child device explicitly from here to
+ * guarantee that the child will be probed after the timing
+ * parameters for the bus are written.
+ */
+ err = of_platform_populate(node, NULL, NULL, dev);
+ if (err < 0) {
+ mvebu_mbus_del_window(base, size);
+ return err;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id mvebu_devbus_of_match[] = {
+ { .compatible = "marvell,mvebu-devbus" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mvebu_devbus_of_match);
+
+static struct platform_driver mvebu_devbus_driver = {
+ .probe = mvebu_devbus_probe,
+ .driver = {
+ .name = "mvebu-devbus",
+ .owner = THIS_MODULE,
+ .of_match_table = mvebu_devbus_of_match,
+ },
+};
+
+static int __init mvebu_devbus_init(void)
+{
+ return platform_driver_register(&mvebu_devbus_driver);
+}
+module_init(mvebu_devbus_init);
+
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Ezequiel Garcia <ezequiel.garcia@free-electrons.com>");
+MODULE_DESCRIPTION("Marvell EBU SoC Device Bus controller");
projects / mirror_ubuntu-bionic-kernel.git / commitdiff