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From: Alexandre Courbot <acourbot@nvidia.com>
To: Grant Likely <grant.likely@secretlab.ca>,
	Linus Walleij <linus.walleij@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, gnurou@gmail.com,
	Alexandre Courbot <acourbot@nvidia.com>
Subject: [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base
Date: Sun,  3 Feb 2013 01:29:28 +0900	[thread overview]
Message-ID: <1359822572-26009-7-git-send-email-acourbot@nvidia.com> (raw)
In-Reply-To: <1359822572-26009-1-git-send-email-acourbot@nvidia.com>

Re-implement gpiochip_find_base using the list of chips instead of the
global gpio_desc[] array. This makes it both simpler and more efficient,
and is needed to remove the global descriptors array.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpio/gpiolib.c | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e473ded..af4c350 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -126,30 +126,25 @@ struct gpio_chip *gpio_to_chip(unsigned gpio)
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
-	int i;
-	int spare = 0;
-	int base = -ENOSPC;
-
-	for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
-		struct gpio_desc *desc = &gpio_desc[i];
-		struct gpio_chip *chip = desc->chip;
-
-		if (!chip) {
-			spare++;
-			if (spare == ngpio) {
-				base = i;
-				break;
-			}
-		} else {
-			spare = 0;
-			if (chip)
-				i -= chip->ngpio - 1;
-		}
+	struct gpio_chip *chip;
+	int base = ARCH_NR_GPIOS - ngpio;
+
+	list_for_each_entry_reverse(chip, &gpio_chips, list) {
+		/* found a free space? */
+		if (chip->base + chip->ngpio <= base)
+			break;
+		else
+			/* nope, check the space right before the chip */
+			base = chip->base - ngpio;
 	}
 
-	if (gpio_is_valid(base))
+	if (gpio_is_valid(base)) {
 		pr_debug("%s: found new base at %d\n", __func__, base);
-	return base;
+		return base;
+	} else {
+		pr_err("%s: cannot find free range\n", __func__);
+		return -ENOSPC;
+	}
 }
 
 /* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
-- 
1.8.1.1


WARNING: multiple messages have this Message-ID (diff)
From: acourbot@nvidia.com (Alexandre Courbot)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base
Date: Sun,  3 Feb 2013 01:29:28 +0900	[thread overview]
Message-ID: <1359822572-26009-7-git-send-email-acourbot@nvidia.com> (raw)
In-Reply-To: <1359822572-26009-1-git-send-email-acourbot@nvidia.com>

Re-implement gpiochip_find_base using the list of chips instead of the
global gpio_desc[] array. This makes it both simpler and more efficient,
and is needed to remove the global descriptors array.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 drivers/gpio/gpiolib.c | 37 ++++++++++++++++---------------------
 1 file changed, 16 insertions(+), 21 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index e473ded..af4c350 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -126,30 +126,25 @@ struct gpio_chip *gpio_to_chip(unsigned gpio)
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
 static int gpiochip_find_base(int ngpio)
 {
-	int i;
-	int spare = 0;
-	int base = -ENOSPC;
-
-	for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
-		struct gpio_desc *desc = &gpio_desc[i];
-		struct gpio_chip *chip = desc->chip;
-
-		if (!chip) {
-			spare++;
-			if (spare == ngpio) {
-				base = i;
-				break;
-			}
-		} else {
-			spare = 0;
-			if (chip)
-				i -= chip->ngpio - 1;
-		}
+	struct gpio_chip *chip;
+	int base = ARCH_NR_GPIOS - ngpio;
+
+	list_for_each_entry_reverse(chip, &gpio_chips, list) {
+		/* found a free space? */
+		if (chip->base + chip->ngpio <= base)
+			break;
+		else
+			/* nope, check the space right before the chip */
+			base = chip->base - ngpio;
 	}
 
-	if (gpio_is_valid(base))
+	if (gpio_is_valid(base)) {
 		pr_debug("%s: found new base at %d\n", __func__, base);
-	return base;
+		return base;
+	} else {
+		pr_err("%s: cannot find free range\n", __func__);
+		return -ENOSPC;
+	}
 }
 
 /* caller ensures gpio is valid and requested, chip->get_direction may sleep  */
-- 
1.8.1.1

  parent reply	other threads:[~2013-02-02 16:27 UTC|newest]

Thread overview: 115+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-02 16:29 [PATCH 0/9] gpiolib: remove gpio_desc[] static array Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 1/9] gpiolib: link all gpio_chips using a list Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 17:00   ` Linus Walleij
2013-02-05 17:00     ` Linus Walleij
2013-02-09  9:20     ` Grant Likely
2013-02-09  9:20       ` Grant Likely
2013-02-02 16:29 ` [PATCH 2/9] gpiolib: use gpio_chips list in gpiolib_sysfs_init Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 17:04   ` Linus Walleij
2013-02-05 17:04     ` Linus Walleij
2013-02-09  9:22     ` Grant Likely
2013-02-09  9:22       ` Grant Likely
2013-02-09  9:22       ` Grant Likely
2013-02-02 16:29 ` [PATCH 3/9] gpiolib: use gpio_chips list in gpiochip_find Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 17:05   ` Linus Walleij
2013-02-05 17:05     ` Linus Walleij
2013-02-09  9:25     ` Grant Likely
2013-02-09  9:25       ` Grant Likely
2013-02-09  9:25       ` Grant Likely
2013-02-02 16:29 ` [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 17:15   ` Linus Walleij
2013-02-05 17:15     ` Linus Walleij
2013-02-09  9:37     ` Grant Likely
2013-02-09  9:37       ` Grant Likely
2013-02-09  9:37       ` Grant Likely
2013-02-09 13:53       ` Alexandre Courbot
2013-02-09 13:53         ` Alexandre Courbot
2013-02-09 13:53         ` Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot [this message]
2013-02-02 16:29   ` [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base Alexandre Courbot
2013-02-05 17:21   ` Linus Walleij
2013-02-05 17:21     ` Linus Walleij
2013-02-06  4:48     ` Alex Courbot
2013-02-06  4:48       ` Alex Courbot
2013-02-06  4:48       ` Alex Courbot
2013-02-09  9:47       ` Grant Likely
2013-02-09  9:47         ` Grant Likely
2013-02-09  9:47         ` Grant Likely
2013-02-02 16:29 ` [PATCH 6/9] gpiolib: use descriptors internally Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 17:53   ` Linus Walleij
2013-02-05 17:53     ` Linus Walleij
2013-02-07  6:57     ` Alexandre Courbot
2013-02-07  6:57       ` Alexandre Courbot
2013-02-07  6:57       ` Alexandre Courbot
2013-02-09  9:17       ` Grant Likely
2013-02-09  9:17         ` Grant Likely
2013-02-09  9:17         ` Grant Likely
2013-02-09  9:17         ` Grant Likely
2013-02-11 14:09         ` Linus Walleij
2013-02-11 14:09           ` Linus Walleij
2013-02-11 14:09           ` Linus Walleij
2013-02-11 15:40           ` Paul Mundt
2013-02-11 15:40             ` Paul Mundt
2013-02-11 15:40             ` Paul Mundt
2013-02-11 17:39           ` Stephen Warren
2013-02-11 17:39             ` Stephen Warren
2013-02-11 17:39             ` Stephen Warren
2013-02-12 12:29             ` Linus Walleij
2013-02-12 12:29               ` Linus Walleij
2013-02-12 12:29               ` Linus Walleij
2013-02-12 15:59               ` Paul Mundt
2013-02-12 15:59                 ` Paul Mundt
2013-02-12 15:59                 ` Paul Mundt
2013-02-12 17:18                 ` Arnd Bergmann
2013-02-12 17:18                   ` Arnd Bergmann
2013-02-12 17:18                   ` Arnd Bergmann
2013-02-09 13:11   ` Grant Likely
2013-02-09 13:11     ` Grant Likely
2013-02-09 13:11     ` Grant Likely
2013-02-09 13:11     ` Grant Likely
2013-02-09 14:15     ` Alexandre Courbot
2013-02-09 14:15       ` Alexandre Courbot
2013-02-09 14:15       ` Alexandre Courbot
2013-02-09 13:24   ` Grant Likely
2013-02-09 13:24     ` Grant Likely
2013-02-09 13:24     ` Grant Likely
2013-02-09 13:24     ` Grant Likely
2013-02-09 14:18     ` Alexandre Courbot
2013-02-09 14:18       ` Alexandre Courbot
2013-02-09 14:18       ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 7/9] gpiolib: let gpio_chip reference its descriptors Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 18:00   ` Linus Walleij
2013-02-05 18:00     ` Linus Walleij
2013-02-09 13:28     ` Grant Likely
2013-02-09 13:28       ` Grant Likely
2013-02-02 16:29 ` [PATCH 8/9] gpiolib: use gpio_chips list in gpio_to_desc Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 18:01   ` Linus Walleij
2013-02-05 18:01     ` Linus Walleij
2013-02-05 18:01     ` Linus Walleij
2013-02-09  9:58   ` Grant Likely
2013-02-09  9:58     ` Grant Likely
2013-02-09  9:58     ` Grant Likely
2013-02-09  9:58     ` Grant Likely
2013-02-09 14:21     ` Alexandre Courbot
2013-02-09 14:21       ` Alexandre Courbot
2013-02-09 14:21       ` Alexandre Courbot
2013-02-09 14:37       ` Grant Likely
2013-02-09 14:37         ` Grant Likely
2013-02-09 14:37         ` Grant Likely
2013-02-02 16:29 ` [PATCH 9/9] gpiolib: dynamically allocate descriptors array Alexandre Courbot
2013-02-02 16:29   ` Alexandre Courbot
2013-02-05 18:02   ` Linus Walleij
2013-02-05 18:02     ` Linus Walleij

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