| /* |
| * 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/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 |
| * |
| * The "from" region may straddle more than one window, so toggle the GPIOs for |
| * each window region before reading its data. |
| */ |
| 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); |
| |
| int this_len; |
| |
| while (len) { |
| if ((from % state->win_size) + len > state->win_size) |
| this_len = state->win_size - (from % state->win_size); |
| else |
| this_len = len; |
| |
| gf_set_gpios(state, from); |
| memcpy_fromio(to, map->virt + (from % state->win_size), |
| this_len); |
| len -= this_len; |
| from += this_len; |
| to += this_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); |
| |
| int this_len; |
| |
| while (len) { |
| if ((to % state->win_size) + len > state->win_size) |
| this_len = state->win_size - (to % state->win_size); |
| else |
| this_len = len; |
| |
| gf_set_gpios(state, to); |
| memcpy_toio(map->virt + (to % state->win_size), from, len); |
| |
| len -= this_len; |
| to += this_len; |
| from += this_len; |
| } |
| } |
| |
| static const char * const 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 = dev_get_platdata(&pdev->dev); |
| 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"); |