diff options
| -rw-r--r-- | drivers/mtd/maps/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/mtd/maps/Makefile | 3 | ||||
| -rw-r--r-- | drivers/mtd/maps/gpio-addr-flash.c | 311 |
3 files changed, 322 insertions, 2 deletions
diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig index 0f314eb..3a9a960 100644 --- a/drivers/mtd/maps/Kconfig +++ b/drivers/mtd/maps/Kconfig @@ -484,6 +484,16 @@ config MTD_BFIN_ASYNC If compiled as a module, it will be called bfin-async-flash. +config MTD_GPIO_ADDR + tristate "GPIO-assisted Flash Chip Support" + depends on MTD_COMPLEX_MAPPINGS + select MTD_PARTITIONS + help + Map driver which allows flashes to be partially physically addressed + and assisted by GPIOs. + + If compiled as a module, it will be called gpio-addr-flash. + config MTD_UCLINUX bool "Generic uClinux RAM/ROM filesystem support" depends on MTD_PARTITIONS && MTD_RAM=y && !MMU diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile index 5beb066..1d5cf86 100644 --- a/drivers/mtd/maps/Makefile +++ b/drivers/mtd/maps/Makefile @@ -58,5 +58,4 @@ obj-$(CONFIG_MTD_PLATRAM) += plat-ram.o obj-$(CONFIG_MTD_OMAP_NOR) += omap_nor.o obj-$(CONFIG_MTD_INTEL_VR_NOR) += intel_vr_nor.o obj-$(CONFIG_MTD_BFIN_ASYNC) += bfin-async-flash.o -obj-$(CONFIG_MTD_RBTX4939) += rbtx4939-flash.o -obj-$(CONFIG_MTD_VMU) += vmu-flash.o +obj-$(CONFIG_MTD_GPIO_ADDR) += gpio-addr-flash.o diff --git a/drivers/mtd/maps/gpio-addr-flash.c b/drivers/mtd/maps/gpio-addr-flash.c new file mode 100644 index 0000000..44ef9a4 --- /dev/null +++ b/drivers/mtd/maps/gpio-addr-flash.c @@ -0,0 +1,311 @@ +/* + * 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/init.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/types.h> + +#include <asm/gpio.h> +#include <asm/io.h> + +#define pr_devinit(fmt, args...) ({ static const __devinitconst 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); +} + +#ifdef CONFIG_MTD_PARTITIONS +static const char *part_probe_types[] = { "cmdlinepart", "RedBoot", NULL }; +#endif + +/** + * 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 __devinit gpio_flash_probe(struct platform_device *pdev) +{ + int ret; + 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; + + state->gpio_count = gpios->end; + state->gpio_addrs = (void *)gpios->start; + state->gpio_values = (void *)(state + 1); + state->win_size = memory->end - memory->start + 1; + 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 = (void __iomem *)memory->start; + 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; + } + +#ifdef CONFIG_MTD_PARTITIONS + ret = parse_mtd_partitions(state->mtd, part_probe_types, &pdata->parts, 0); + if (ret > 0) { + pr_devinit(KERN_NOTICE PFX "Using commandline partition definition\n"); + add_mtd_partitions(state->mtd, pdata->parts, ret); + kfree(pdata->parts); + + } else if (pdata->nr_parts) { + pr_devinit(KERN_NOTICE PFX "Using board partition definition\n"); + add_mtd_partitions(state->mtd, pdata->parts, pdata->nr_parts); + + } else +#endif + { + pr_devinit(KERN_NOTICE PFX "no partition info available, registering whole flash at once\n"); + add_mtd_device(state->mtd); + } + + return 0; +} + +static int __devexit 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); +#ifdef CONFIG_MTD_PARTITIONS + del_mtd_partitions(state->mtd); +#endif + map_destroy(state->mtd); + kfree(state); + return 0; +} + +static struct platform_driver gpio_flash_driver = { + .probe = gpio_flash_probe, + .remove = __devexit_p(gpio_flash_remove), + .driver = { + .name = DRIVER_NAME, + }, +}; + +static int __init gpio_flash_init(void) +{ + return platform_driver_register(&gpio_flash_driver); +} +module_init(gpio_flash_init); + +static void __exit gpio_flash_exit(void) +{ + platform_driver_unregister(&gpio_flash_driver); +} +module_exit(gpio_flash_exit); + +MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); +MODULE_DESCRIPTION("MTD map driver for flashes addressed physically and with gpios"); +MODULE_LICENSE("GPL"); |