linux/drivers/mtd/maps/gpio-addr-flash.c

289 lines
8.0 KiB
C
Raw Normal View History

/*
* 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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#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");