From: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
To: David Woodhouse <dwmw2@infradead.org>,
Brian Norris <computersforpeace@gmail.com>,
Boris Brezillon <boris.brezillon@bootlin.com>,
Marek Vasut <marek.vasut@gmail.com>,
Richard Weinberger <richard@nod.at>,
Zhouyang Jia <jiazhouyang09@gmail.com>,
linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Subject: [PATCH 5/8] mtd: maps: gpio-addr-flash: Replace array with an integer
Date: Tue, 21 Aug 2018 16:31:49 +0200 [thread overview]
Message-ID: <20180821143152.32293-6-ricardo.ribalda@gmail.com> (raw)
In-Reply-To: <20180821143152.32293-1-ricardo.ribalda@gmail.com>
By replacing the array with an integer we can avoid completely
the bit comparison loop if the value has not changed (by far
the most common case).
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
drivers/mtd/maps/gpio-addr-flash.c | 31 +++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/drivers/mtd/maps/gpio-addr-flash.c b/drivers/mtd/maps/gpio-addr-flash.c
index 22e100f07112..8f5e3dce9be3 100644
--- a/drivers/mtd/maps/gpio-addr-flash.c
+++ b/drivers/mtd/maps/gpio-addr-flash.c
@@ -43,7 +43,7 @@ struct async_state {
struct map_info map;
size_t gpio_count;
unsigned *gpio_addrs;
- int *gpio_values;
+ unsigned int gpio_values;
unsigned int win_order;
};
#define gf_map_info_to_state(mi) ((struct async_state *)(mi)->map_priv_1)
@@ -55,22 +55,25 @@ struct async_state {
*
* 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.
+ * type).
*/
static void gf_set_gpios(struct async_state *state, unsigned long ofs)
{
- size_t i = 0;
- int value;
+ int i;
ofs >>= state->win_order;
- 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);
+
+ if (ofs == state->gpio_values)
+ return;
+
+ for (i = 0; i < state->gpio_count; i++) {
+ if ((ofs & BIT(i)) == (state->gpio_values & BIT(i)))
+ continue;
+
+ gpio_set_value(state->gpio_addrs[i], !!(ofs & BIT(i)));
+ }
+
+ state->gpio_values = ofs;
}
/**
@@ -215,7 +218,7 @@ static int gpio_flash_probe(struct platform_device *pdev)
if (!memory || !gpios || !gpios->end)
return -EINVAL;
- arr_size = sizeof(int) * gpios->end;
+ arr_size = sizeof(state->gpio_addrs[0]) * gpios->end;
state = devm_kzalloc(&pdev->dev, sizeof(*state) + arr_size, GFP_KERNEL);
if (!state)
return -ENOMEM;
@@ -226,9 +229,7 @@ static int gpio_flash_probe(struct platform_device *pdev)
*/
state->gpio_count = gpios->end;
state->gpio_addrs = (void *)(unsigned long)gpios->start;
- state->gpio_values = (void *)(state + 1);
state->win_order = get_bitmask_order(resource_size(memory)) - 1;
- memset(state->gpio_values, 0xff, arr_size);
state->map.name = DRIVER_NAME;
state->map.read = gf_read;
--
2.18.0
next prev parent reply other threads:[~2018-08-21 14:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-21 14:31 [PATCH 0/8] gpio-addr-flash: Support for device-tree and cleanup Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 1/8] mtd: maps: gpio-addr-flash: Replace custom printk Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 2/8] mtd: maps: gpio-addr-flash: Fix ioremapped size Ricardo Ribalda Delgado
2018-08-28 14:26 ` Boris Brezillon
2018-08-28 14:44 ` Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 3/8] mtd: maps: gpio-addr-flash: Use devm_* functions Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 4/8] mtd: maps: gpio-addr-flash: Use order insted of size Ricardo Ribalda Delgado
2018-08-21 14:31 ` Ricardo Ribalda Delgado [this message]
2018-08-21 14:31 ` [PATCH 6/8] mtd: maps: gpio-addr-flash: Split allocation in two Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 7/8] mtd: maps: gpio-addr-flash: Add support for device-tree devices Ricardo Ribalda Delgado
2018-08-21 14:31 ` [PATCH 8/8] dt-binding: mtd: Document gpio-addr-flash Ricardo Ribalda Delgado
2018-08-31 12:17 ` Rob Herring
2018-08-31 12:20 ` Ricardo Ribalda Delgado
2018-09-04 14:04 ` [PATCH 0/8] gpio-addr-flash: Support for device-tree and cleanup Ricardo Ribalda Delgado
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