drivers/memory/mvebu-devbus.c - maze/linux - Git at Google

 /*
  * 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");
	/*
	* 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");