[deliverable/linux.git] / drivers / mtd / maps / gpio-addr-flash.c

/*
 * drivers/mtd/maps/gpio-addr-flash.c
 *
 * Handle the case where a flash device is mostly addressed using physical
 * line and supplemented by GPIOs.  This way you can hook up say a 8MiB flash
 * to a 2MiB memory range and use the GPIOs to select a particular range.
 *
 * Copyright © 2000 Nicolas Pitre <nico@cam.org>
 * Copyright © 2005-2009 Analog Devices Inc.
 *
 * Enter bugs at http://blackfin.uclinux.org/
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/physmap.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>

#define pr_devinit(fmt, args...) \
	({ static const char __fmt[] = fmt; printk(__fmt, ## args); })

#define DRIVER_NAME "gpio-addr-flash"
#define PFX DRIVER_NAME ": "

/**
 * struct async_state - keep GPIO flash state
 *	@mtd:         MTD state for this mapping
 *	@map:         MTD map state for this flash
 *	@gpio_count:  number of GPIOs used to address
 *	@gpio_addrs:  array of GPIOs to twiddle
 *	@gpio_values: cached GPIO values
 *	@win_size:    dedicated memory size (if no GPIOs)
 */
struct async_state {
	struct mtd_info *mtd;
	struct map_info map;
	size_t gpio_count;
	unsigned *gpio_addrs;
	int *gpio_values;
	unsigned long win_size;
};
#define gf_map_info_to_state(mi) ((struct async_state *)(mi)->map_priv_1)

/**
 * gf_set_gpios() - set GPIO address lines to access specified flash offset
 *	@state: GPIO flash state
 *	@ofs:   desired offset to access
 *
 * Rather than call the GPIO framework every time, cache the last-programmed
 * value.  This speeds up sequential accesses (which are by far the most common
 * type).  We rely on the GPIO framework to treat non-zero value as high so
 * that we don't have to normalize the bits.
 */
static void gf_set_gpios(struct async_state *state, unsigned long ofs)
{
	size_t i = 0;
	int value;
	ofs /= state->win_size;
	do {
		value = ofs & (1 << i);
		if (state->gpio_values[i] != value) {
			gpio_set_value(state->gpio_addrs[i], value);
			state->gpio_values[i] = value;
		}
	} while (++i < state->gpio_count);
}

/**
 * gf_read() - read a word at the specified offset
 *	@map: MTD map state
 *	@ofs: desired offset to read
 */
static map_word gf_read(struct map_info *map, unsigned long ofs)
{
	struct async_state *state = gf_map_info_to_state(map);
	uint16_t word;
	map_word test;

	gf_set_gpios(state, ofs);

	word = readw(map->virt + (ofs % state->win_size));
	test.x[0] = word;
	return test;
}

/**
 * gf_copy_from() - copy a chunk of data from the flash
 *	@map:  MTD map state
 *	@to:   memory to copy to
 *	@from: flash offset to copy from
 *	@len:  how much to copy
 *
 * We rely on the MTD layer to chunk up copies such that a single request here
 * will not cross a window size.  This allows us to only wiggle the GPIOs once
 * before falling back to a normal memcpy.  Reading the higher layer code shows
 * that this is indeed the case, but add a BUG_ON() to future proof.
 */
static void gf_copy_from(struct map_info *map, void *to, unsigned long from, ssize_t len)
{
	struct async_state *state = gf_map_info_to_state(map);

	gf_set_gpios(state, from);

	/* BUG if operation crosses the win_size */
	BUG_ON(!((from + len) % state->win_size <= (from + len)));

	/* operation does not cross the win_size, so one shot it */
	memcpy_fromio(to, map->virt + (from % state->win_size), len);
}

/**
 * gf_write() - write a word at the specified offset
 *	@map: MTD map state
 *	@ofs: desired offset to write
 */
static void gf_write(struct map_info *map, map_word d1, unsigned long ofs)
{
	struct async_state *state = gf_map_info_to_state(map);
	uint16_t d;

	gf_set_gpios(state, ofs);

	d = d1.x[0];
	writew(d, map->virt + (ofs % state->win_size));
}

/**
 * gf_copy_to() - copy a chunk of data to the flash
 *	@map:  MTD map state
 *	@to:   flash offset to copy to
 *	@from: memory to copy from
 *	@len:  how much to copy
 *
 * See gf_copy_from() caveat.
 */
static void gf_copy_to(struct map_info *map, unsigned long to,
		       const void *from, ssize_t len)
{
	struct async_state *state = gf_map_info_to_state(map);

	gf_set_gpios(state, to);

	/* BUG if operation crosses the win_size */
	BUG_ON(!((to + len) % state->win_size <= (to + len)));

	/* operation does not cross the win_size, so one shot it */
	memcpy_toio(map->virt + (to % state->win_size), from, len);
}

static const char *part_probe_types[] = { "cmdlinepart", "RedBoot", NULL };

/**
 * gpio_flash_probe() - setup a mapping for a GPIO assisted flash
 *	@pdev: platform device
 *
 * The platform resource layout expected looks something like:
 * struct mtd_partition partitions[] = { ... };
 * struct physmap_flash_data flash_data = { ... };
 * unsigned flash_gpios[] = { GPIO_XX, GPIO_XX, ... };
 * struct resource flash_resource[] = {
 *	{
 *		.name  = "cfi_probe",
 *		.start = 0x20000000,
 *		.end   = 0x201fffff,
 *		.flags = IORESOURCE_MEM,
 *	}, {
 *		.start = (unsigned long)flash_gpios,
 *		.end   = ARRAY_SIZE(flash_gpios),
 *		.flags = IORESOURCE_IRQ,
 *	}
 * };
 * struct platform_device flash_device = {
 *	.name          = "gpio-addr-flash",
 *	.dev           = { .platform_data = &flash_data, },
 *	.num_resources = ARRAY_SIZE(flash_resource),
 *	.resource      = flash_resource,
 *	...
 * };
 */
static int gpio_flash_probe(struct platform_device *pdev)
{
	size_t i, arr_size;
	struct physmap_flash_data *pdata;
	struct resource *memory;
	struct resource *gpios;
	struct async_state *state;

	pdata = pdev->dev.platform_data;
	memory = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	gpios = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

	if (!memory || !gpios || !gpios->end)
		return -EINVAL;

	arr_size = sizeof(int) * gpios->end;
	state = kzalloc(sizeof(*state) + arr_size, GFP_KERNEL);
	if (!state)
		return -ENOMEM;

	/*
	 * We cast start/end to known types in the boards file, so cast
	 * away their pointer types here to the known types (gpios->xxx).
	 */
	state->gpio_count     = gpios->end;
	state->gpio_addrs     = (void *)(unsigned long)gpios->start;
	state->gpio_values    = (void *)(state + 1);
	state->win_size       = resource_size(memory);
	memset(state->gpio_values, 0xff, arr_size);

	state->map.name       = DRIVER_NAME;
	state->map.read       = gf_read;
	state->map.copy_from  = gf_copy_from;
	state->map.write      = gf_write;
	state->map.copy_to    = gf_copy_to;
	state->map.bankwidth  = pdata->width;
	state->map.size       = state->win_size * (1 << state->gpio_count);
	state->map.virt       = ioremap_nocache(memory->start, state->map.size);
	state->map.phys       = NO_XIP;
	state->map.map_priv_1 = (unsigned long)state;

	platform_set_drvdata(pdev, state);

	i = 0;
	do {
		if (gpio_request(state->gpio_addrs[i], DRIVER_NAME)) {
			pr_devinit(KERN_ERR PFX "failed to request gpio %d\n",
				state->gpio_addrs[i]);
			while (i--)
				gpio_free(state->gpio_addrs[i]);
			kfree(state);
			return -EBUSY;
		}
		gpio_direction_output(state->gpio_addrs[i], 0);
	} while (++i < state->gpio_count);

	pr_devinit(KERN_NOTICE PFX "probing %d-bit flash bus\n",
		state->map.bankwidth * 8);
	state->mtd = do_map_probe(memory->name, &state->map);
	if (!state->mtd) {
		for (i = 0; i < state->gpio_count; ++i)
			gpio_free(state->gpio_addrs[i]);
		kfree(state);
		return -ENXIO;
	}


	mtd_device_parse_register(state->mtd, part_probe_types, NULL,
				  pdata->parts, pdata->nr_parts);

	return 0;
}

static int gpio_flash_remove(struct platform_device *pdev)
{
	struct async_state *state = platform_get_drvdata(pdev);
	size_t i = 0;
	do {
		gpio_free(state->gpio_addrs[i]);
	} while (++i < state->gpio_count);
	mtd_device_unregister(state->mtd);
	map_destroy(state->mtd);
	kfree(state);
	return 0;
}

static struct platform_driver gpio_flash_driver = {
	.probe		= gpio_flash_probe,
	.remove		= gpio_flash_remove,
	.driver		= {
		.name	= DRIVER_NAME,
	},
};

module_platform_driver(gpio_flash_driver);

MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
MODULE_DESCRIPTION("MTD map driver for flashes addressed physically and with gpios");
MODULE_LICENSE("GPL");
Commit	Line	Data
d79c326c MF	1	/*
	2	* drivers/mtd/maps/gpio-addr-flash.c
	3	*
	4	* Handle the case where a flash device is mostly addressed using physical
	5	* line and supplemented by GPIOs. This way you can hook up say a 8MiB flash
	6	* to a 2MiB memory range and use the GPIOs to select a particular range.
	7	*
	8	* Copyright © 2000 Nicolas Pitre <nico@cam.org>
	9	* Copyright © 2005-2009 Analog Devices Inc.
	10	*
	11	* Enter bugs at http://blackfin.uclinux.org/
	12	*
	13	* Licensed under the GPL-2 or later.
	14	*/
	15
f5bae56a	16	#include <linux/gpio.h>
d79c326c	17	#include <linux/init.h>
f5bae56a	18	#include <linux/io.h>
d79c326c MF	19	#include <linux/kernel.h>
	20	#include <linux/module.h>
	21	#include <linux/mtd/mtd.h>
	22	#include <linux/mtd/map.h>
	23	#include <linux/mtd/partitions.h>
	24	#include <linux/mtd/physmap.h>
	25	#include <linux/platform_device.h>
5a0e3ad6	26	#include <linux/slab.h>
d79c326c MF	27	#include <linux/types.h>
d79c326c MF	28
7bf350b7 AB	29	#define pr_devinit(fmt, args...) \
7bf350b7 AB	30	({ static const char __fmt[] = fmt; printk(__fmt, ## args); })
d79c326c MF	31
	32	#define DRIVER_NAME "gpio-addr-flash"
	33	#define PFX DRIVER_NAME ": "
	34
	35	/**
	36	* struct async_state - keep GPIO flash state
	37	* @mtd: MTD state for this mapping
	38	* @map: MTD map state for this flash
	39	* @gpio_count: number of GPIOs used to address
	40	* @gpio_addrs: array of GPIOs to twiddle
	41	* @gpio_values: cached GPIO values
	42	* @win_size: dedicated memory size (if no GPIOs)
	43	*/
	44	struct async_state {
	45	struct mtd_info *mtd;
	46	struct map_info map;
	47	size_t gpio_count;
	48	unsigned *gpio_addrs;
	49	int *gpio_values;
	50	unsigned long win_size;
	51	};
	52	#define gf_map_info_to_state(mi) ((struct async_state *)(mi)->map_priv_1)
	53
	54	/**
	55	* gf_set_gpios() - set GPIO address lines to access specified flash offset
	56	* @state: GPIO flash state
	57	* @ofs: desired offset to access
	58	*
	59	* Rather than call the GPIO framework every time, cache the last-programmed
	60	* value. This speeds up sequential accesses (which are by far the most common
	61	* type). We rely on the GPIO framework to treat non-zero value as high so
	62	* that we don't have to normalize the bits.
	63	*/
	64	static void gf_set_gpios(struct async_state *state, unsigned long ofs)
	65	{
	66	size_t i = 0;
	67	int value;
	68	ofs /= state->win_size;
	69	do {
	70	value = ofs & (1 << i);
	71	if (state->gpio_values[i] != value) {
	72	gpio_set_value(state->gpio_addrs[i], value);
	73	state->gpio_values[i] = value;
	74	}
	75	} while (++i < state->gpio_count);
	76	}
	77
	78	/**
	79	* gf_read() - read a word at the specified offset
	80	* @map: MTD map state
	81	* @ofs: desired offset to read
	82	*/
	83	static map_word gf_read(struct map_info *map, unsigned long ofs)
	84	{
	85	struct async_state *state = gf_map_info_to_state(map);
	86	uint16_t word;
	87	map_word test;
	88
	89	gf_set_gpios(state, ofs);
	90
	91	word = readw(map->virt + (ofs % state->win_size));
	92	test.x[0] = word;
	93	return test;
	94	}
95
96	/**
97	* gf_copy_from() - copy a chunk of data from the flash
98	* @map: MTD map state
99	* @to: memory to copy to
100	* @from: flash offset to copy from
101	* @len: how much to copy
102	*
103	* We rely on the MTD layer to chunk up copies such that a single request here
104	* will not cross a window size. This allows us to only wiggle the GPIOs once
105	* before falling back to a normal memcpy. Reading the higher layer code shows
106	* that this is indeed the case, but add a BUG_ON() to future proof.
107	*/
108	static void gf_copy_from(struct map_info map, void to, unsigned long from, ssize_t len)
109	{
110	struct async_state *state = gf_map_info_to_state(map);
111
112	gf_set_gpios(state, from);
113
114	/* BUG if operation crosses the win_size */
115	BUG_ON(!((from + len) % state->win_size <= (from + len)));
116
117	/* operation does not cross the win_size, so one shot it */
118	memcpy_fromio(to, map->virt + (from % state->win_size), len);
119	}
120
121	/**
122	* gf_write() - write a word at the specified offset
123	* @map: MTD map state
124	* @ofs: desired offset to write
125	*/
126	static void gf_write(struct map_info *map, map_word d1, unsigned long ofs)
127	{
128	struct async_state *state = gf_map_info_to_state(map);
129	uint16_t d;
130
131	gf_set_gpios(state, ofs);
132
133	d = d1.x[0];
134	writew(d, map->virt + (ofs % state->win_size));
135	}
136
137	/**
138	* gf_copy_to() - copy a chunk of data to the flash
139	* @map: MTD map state
140	* @to: flash offset to copy to
141	* @from: memory to copy from
142	* @len: how much to copy
143	*
144	* See gf_copy_from() caveat.
145	*/
7bf350b7 AB	146	static void gf_copy_to(struct map_info *map, unsigned long to,
7bf350b7 AB	147	const void *from, ssize_t len)
d79c326c MF	148	{
	149	struct async_state *state = gf_map_info_to_state(map);
	150
	151	gf_set_gpios(state, to);
	152
	153	/* BUG if operation crosses the win_size */
	154	BUG_ON(!((to + len) % state->win_size <= (to + len)));
	155
	156	/* operation does not cross the win_size, so one shot it */
	157	memcpy_toio(map->virt + (to % state->win_size), from, len);
	158	}
	159
d79c326c	160	static const char *part_probe_types[] = { "cmdlinepart", "RedBoot", NULL };
d79c326c MF	161
	162	/**
	163	* gpio_flash_probe() - setup a mapping for a GPIO assisted flash
	164	* @pdev: platform device
	165	*
	166	* The platform resource layout expected looks something like:
	167	* struct mtd_partition partitions[] = { ... };
	168	* struct physmap_flash_data flash_data = { ... };
	169	* unsigned flash_gpios[] = { GPIO_XX, GPIO_XX, ... };
	170	* struct resource flash_resource[] = {
	171	* {
	172	* .name = "cfi_probe",
	173	* .start = 0x20000000,
	174	* .end = 0x201fffff,
	175	* .flags = IORESOURCE_MEM,
	176	* }, {
	177	* .start = (unsigned long)flash_gpios,
	178	* .end = ARRAY_SIZE(flash_gpios),
	179	* .flags = IORESOURCE_IRQ,
	180	* }
	181	* };
	182	* struct platform_device flash_device = {
	183	* .name = "gpio-addr-flash",
	184	* .dev = { .platform_data = &flash_data, },
	185	* .num_resources = ARRAY_SIZE(flash_resource),
	186	* .resource = flash_resource,
	187	* ...
	188	* };
	189	*/
06f25510	190	static int gpio_flash_probe(struct platform_device *pdev)
d79c326c	191	{
d79c326c MF	192	size_t i, arr_size;
	193	struct physmap_flash_data *pdata;
	194	struct resource *memory;
	195	struct resource *gpios;
	196	struct async_state *state;
	197
	198	pdata = pdev->dev.platform_data;
	199	memory = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	200	gpios = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	201
	202	if (!memory \|\| !gpios \|\| !gpios->end)
	203	return -EINVAL;
	204
	205	arr_size = sizeof(int) * gpios->end;
	206	state = kzalloc(sizeof(*state) + arr_size, GFP_KERNEL);
	207	if (!state)
	208	return -ENOMEM;
	209
ebd71e3a MF	210	/*
	211	* We cast start/end to known types in the boards file, so cast
	212	* away their pointer types here to the known types (gpios->xxx).
	213	*/
d79c326c	214	state->gpio_count = gpios->end;
ebd71e3a	215	state->gpio_addrs = (void *)(unsigned long)gpios->start;
d79c326c	216	state->gpio_values = (void *)(state + 1);
ebd71e3a	217	state->win_size = resource_size(memory);
d79c326c MF	218	memset(state->gpio_values, 0xff, arr_size);
	219
	220	state->map.name = DRIVER_NAME;
	221	state->map.read = gf_read;
	222	state->map.copy_from = gf_copy_from;
	223	state->map.write = gf_write;
	224	state->map.copy_to = gf_copy_to;
	225	state->map.bankwidth = pdata->width;
	226	state->map.size = state->win_size * (1 << state->gpio_count);
ebd71e3a	227	state->map.virt = ioremap_nocache(memory->start, state->map.size);
d79c326c MF	228	state->map.phys = NO_XIP;
	229	state->map.map_priv_1 = (unsigned long)state;
	230
	231	platform_set_drvdata(pdev, state);
	232
	233	i = 0;
	234	do {
	235	if (gpio_request(state->gpio_addrs[i], DRIVER_NAME)) {
	236	pr_devinit(KERN_ERR PFX "failed to request gpio %d\n",
	237	state->gpio_addrs[i]);
	238	while (i--)
	239	gpio_free(state->gpio_addrs[i]);
	240	kfree(state);
	241	return -EBUSY;
	242	}
	243	gpio_direction_output(state->gpio_addrs[i], 0);
	244	} while (++i < state->gpio_count);
	245
	246	pr_devinit(KERN_NOTICE PFX "probing %d-bit flash bus\n",
	247	state->map.bankwidth * 8);
	248	state->mtd = do_map_probe(memory->name, &state->map);
	249	if (!state->mtd) {
	250	for (i = 0; i < state->gpio_count; ++i)
	251	gpio_free(state->gpio_addrs[i]);
	252	kfree(state);
	253	return -ENXIO;
	254	}
	255
d79c326c	256
42d7fbe2 AB	257	mtd_device_parse_register(state->mtd, part_probe_types, NULL,
42d7fbe2 AB	258	pdata->parts, pdata->nr_parts);
fdbf3bf6	259
d79c326c MF	260	return 0;
	261	}
	262
810b7e06	263	static int gpio_flash_remove(struct platform_device *pdev)
d79c326c MF	264	{
	265	struct async_state *state = platform_get_drvdata(pdev);
	266	size_t i = 0;
	267	do {
	268	gpio_free(state->gpio_addrs[i]);
	269	} while (++i < state->gpio_count);
fdbf3bf6	270	mtd_device_unregister(state->mtd);
d79c326c MF	271	map_destroy(state->mtd);
	272	kfree(state);
	273	return 0;
	274	}
	275
	276	static struct platform_driver gpio_flash_driver = {
	277	.probe = gpio_flash_probe,
5153b88c	278	.remove = gpio_flash_remove,
d79c326c MF	279	.driver = {
	280	.name = DRIVER_NAME,
	281	},
	282	};
	283
f99640de	284	module_platform_driver(gpio_flash_driver);
d79c326c MF	285
	286	MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
	287	MODULE_DESCRIPTION("MTD map driver for flashes addressed physically and with gpios");
	288	MODULE_LICENSE("GPL");