/* * 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 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 devbus *devbus;	struct resource *res;	struct clk *clk;	unsigned long rate;	int err; 	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; 	/*	 * 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)		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");