Modified: trunk/drivers/mtd/maps/gpio-addr-flash.c (6560 => 6561)
--- trunk/drivers/mtd/maps/gpio-addr-flash.c 2009-06-03 11:16:48 UTC (rev 6560)
+++ trunk/drivers/mtd/maps/gpio-addr-flash.c 2009-06-03 12:17:58 UTC (rev 6561)
@@ -6,7 +6,7 @@
* to a 2meg memory range and use the GPIOs to select a particular range.
*
* Copyright 2000 Nicolas Pitre <[email protected]>
- * Copyright 2005-2008 Analog Devices Inc.
+ * Copyright 2005-2009 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
@@ -29,7 +29,17 @@
#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;
@@ -38,23 +48,40 @@
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;
+ size_t i = 0;
int value;
- for (i = 0; i < state->gpio_count; ++i) {
- value = !!((ofs / state->win_size) & (1 << i));
+ 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 = (struct async_state *)map->map_priv_1;
+ struct async_state *state = gf_map_info_to_state(map);
u16 word;
map_word test;
@@ -65,22 +92,39 @@
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 = (struct async_state *)map->map_priv_1;
+ struct async_state *state = gf_map_info_to_state(map);
gf_set_gpios(state, from);
- /* BUG if operation crosss the win_size */
+ /* 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 = (struct async_state *)map->map_priv_1;
+ struct async_state *state = gf_map_info_to_state(map);
u16 d;
gf_set_gpios(state, ofs);
@@ -89,13 +133,22 @@
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 = (struct async_state *)map->map_priv_1;
+ struct async_state *state = gf_map_info_to_state(map);
gf_set_gpios(state, to);
- /* BUG if operation crosss the win_size */
+ /* 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 */
@@ -106,26 +159,60 @@
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;
- struct physmap_flash_data *pdata = pdev->dev.platform_data;
- struct resource *memory = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- struct resource *gpios = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+ size_t i, arr_size;
+ struct physmap_flash_data *pdata;
+ struct resource *memory;
+ struct resource *gpios;
struct async_state *state;
- state = kzalloc(sizeof(*state) + (sizeof(int) * gpios->end * 2), GFP_KERNEL);
+ 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 *)(state + 1);
- state->gpio_values = state->gpio_addrs + state->gpio_count;
+ state->gpio_addrs = (void *)gpios->start;
+ state->gpio_values = (void *)(state + 1);
state->win_size = memory->end - memory->start + 1;
- memcpy(state->gpio_addrs, (void *)gpios->start, sizeof(unsigned) * state->gpio_count);
- for (i = 0; i < state->gpio_count; ++i)
- state->gpio_values[i] = -1;
+ memset(state->gpio_values, 0xff, arr_size);
state->map.name = DRIVER_NAME;
state->map.read = gf_read;
@@ -140,18 +227,21 @@
platform_set_drvdata(pdev, state);
- for (i = 0; i < state->gpio_count; ++i) {
+ i = 0;
+ do {
if (gpio_request(state->gpio_addrs[i], DRIVER_NAME)) {
- pr_devinit(KERN_ERR DRIVER_NAME ": Failed to request gpio %d\n", state->gpio_addrs[i]);
+ 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 DRIVER_NAME ": probing %d-bit flash bus\n", state->map.bankwidth * 8);
+ 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)
@@ -163,18 +253,18 @@
#ifdef CONFIG_MTD_PARTITIONS
ret = parse_mtd_partitions(state->mtd, part_probe_types, &pdata->parts, 0);
if (ret > 0) {
- pr_devinit(KERN_NOTICE DRIVER_NAME ": Using commandline partition definition\n");
+ 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 DRIVER_NAME ": Using board partition definition\n");
+ 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 DRIVER_NAME ": no partition info available, registering whole flash at once\n");
+ pr_devinit(KERN_NOTICE PFX "no partition info available, registering whole flash at once\n");
add_mtd_device(state->mtd);
}
@@ -184,9 +274,10 @@
static int __devexit gpio_flash_remove(struct platform_device *pdev)
{
struct async_state *state = platform_get_drvdata(pdev);
- size_t i;
- for (i = 0; i < state->gpio_count; ++i)
+ 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
