gpio: Add support for microblaze xilinx GPIO

Microblaze uses gpio which is connected to the system reset.
Currently gpio subsystem wasn't used for it.

Add gpio driver and change Microblaze reset logic to be done
via gpio subsystem.

There are various configurations which Microblaze can have
that's why gpio_alloc/gpio_alloc_dual(for dual channel)
function has been introduced and gpio can be allocated
dynamically.

Adding several gpios IP is also possible and supported.

For listing gpio configuration please use "gpio status" command

This patch also remove one compilation warning:
microblaze-generic.c: In function 'do_reset':
microblaze-generic.c:38:47: warning: operation on '*1073741824u'
 may be undefined [-Wsequence-point]

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

2 files changed, 365 insertions, 0 deletions

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 9df1e2632f7..830e8e691a4 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -47,6 +47,7 @@ COBJS-$(CONFIG_OMAP_GPIO)	+= omap_gpio.o
 COBJS-$(CONFIG_DB8500_GPIO)	+= db8500_gpio.o
 COBJS-$(CONFIG_BCM2835_GPIO)	+= bcm2835_gpio.o
 COBJS-$(CONFIG_S3C2440_GPIO)	+= s3c2440_gpio.o
+COBJS-$(CONFIG_XILINX_GPIO)	+= xilinx_gpio.o
 
 COBJS	:= $(COBJS-y)
 SRCS 	:= $(COBJS:.o=.c)
diff --git a/drivers/gpio/xilinx_gpio.c b/drivers/gpio/xilinx_gpio.c
new file mode 100644
index 00000000000..37fb0c50b0b
--- /dev/null
+++ b/drivers/gpio/xilinx_gpio.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (c) 2013 Xilinx, Michal Simek
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <malloc.h>
+#include <linux/list.h>
+#include <asm/io.h>
+#include <asm/gpio.h>
+
+static LIST_HEAD(gpio_list);
+
+enum gpio_direction {
+	GPIO_DIRECTION_OUT = 0,
+	GPIO_DIRECTION_IN = 1,
+};
+
+/* Gpio simple map */
+struct gpio_regs {
+	u32 gpiodata;
+	u32 gpiodir;
+};
+
+#define GPIO_NAME_SIZE	10
+
+struct gpio_names {
+	char name[GPIO_NAME_SIZE];
+};
+
+/* Initialized, rxbd_current, rx_first_buf must be 0 after init */
+struct xilinx_gpio_priv {
+	struct gpio_regs *regs;
+	u32 gpio_min;
+	u32 gpio_max;
+	u32 gpiodata_store;
+	char name[GPIO_NAME_SIZE];
+	struct list_head list;
+	struct gpio_names *gpio_name;
+};
+
+/* Store number of allocated gpio pins */
+static u32 xilinx_gpio_max;
+
+/* Get associated gpio controller */
+static struct xilinx_gpio_priv *gpio_get_controller(unsigned gpio)
+{
+	struct list_head *entry;
+	struct xilinx_gpio_priv *priv = NULL;
+
+	list_for_each(entry, &gpio_list) {
+		priv = list_entry(entry, struct xilinx_gpio_priv, list);
+		if (gpio >= priv->gpio_min && gpio <= priv->gpio_max) {
+			debug("%s: reg: %x, min-max: %d-%d\n", __func__,
+			      (u32)priv->regs, priv->gpio_min, priv->gpio_max);
+			return priv;
+		}
+	}
+	puts("!!!Can't get gpio controller!!!\n");
+	return NULL;
+}
+
+/* Get gpio pin name if used/setup */
+static char *get_name(unsigned gpio)
+{
+	u32 gpio_priv;
+	struct xilinx_gpio_priv *priv;
+
+	debug("%s\n", __func__);
+
+	priv = gpio_get_controller(gpio);
+	if (priv) {
+		gpio_priv = gpio - priv->gpio_min;
+
+		return *priv->gpio_name[gpio_priv].name ?
+			priv->gpio_name[gpio_priv].name : "UNKNOWN";
+	}
+	return "UNKNOWN";
+}
+
+/* Get output value */
+static int gpio_get_output_value(unsigned gpio)
+{
+	u32 val, gpio_priv;
+	struct xilinx_gpio_priv *priv = gpio_get_controller(gpio);
+
+	if (priv) {
+		gpio_priv = gpio - priv->gpio_min;
+		val = !!(priv->gpiodata_store & (1 << gpio_priv));
+		debug("%s: reg: %x, gpio_no: %d, dir: %d\n", __func__,
+		      (u32)priv->regs, gpio_priv, val);
+
+		return val;
+	}
+	return -1;
+}
+
+/* Get input value */
+static int gpio_get_input_value(unsigned gpio)
+{
+	u32 val, gpio_priv;
+	struct gpio_regs *regs;
+	struct xilinx_gpio_priv *priv = gpio_get_controller(gpio);
+
+	if (priv) {
+		regs = priv->regs;
+		gpio_priv = gpio - priv->gpio_min;
+		val = readl(&regs->gpiodata);
+		val = !!(val & (1 << gpio_priv));
+		debug("%s: reg: %x, gpio_no: %d, dir: %d\n", __func__,
+		      (u32)priv->regs, gpio_priv, val);
+
+		return val;
+	}
+	return -1;
+}
+
+/* Set gpio direction */
+static int gpio_set_direction(unsigned gpio, enum gpio_direction direction)
+{
+	u32 val, gpio_priv;
+	struct gpio_regs *regs;
+	struct xilinx_gpio_priv *priv = gpio_get_controller(gpio);
+
+	if (priv) {
+		regs = priv->regs;
+		val = readl(&regs->gpiodir);
+
+		gpio_priv = gpio - priv->gpio_min;
+		if (direction == GPIO_DIRECTION_OUT)
+			val &= ~(1 << gpio_priv);
+		else
+			val |= 1 << gpio_priv;
+
+		writel(val, &regs->gpiodir);
+		debug("%s: reg: %x, gpio_no: %d, dir: %d\n", __func__,
+		      (u32)priv->regs, gpio_priv, val);
+
+		return 0;
+	}
+
+	return -1;
+}
+
+/* Get gpio direction */
+static int gpio_get_direction(unsigned gpio)
+{
+	u32 val, gpio_priv;
+	struct gpio_regs *regs;
+	struct xilinx_gpio_priv *priv = gpio_get_controller(gpio);
+
+	if (priv) {
+		regs = priv->regs;
+		gpio_priv = gpio - priv->gpio_min;
+		val = readl(&regs->gpiodir);
+		val = !!(val & (1 << gpio_priv));
+		debug("%s: reg: %x, gpio_no: %d, dir: %d\n", __func__,
+		      (u32)priv->regs, gpio_priv, val);
+
+		return val;
+	}
+
+	return -1;
+}
+
+/*
+ * Get input value
+ * for example gpio setup to output only can't get input value
+ * which is breaking gpio toggle command
+ */
+int gpio_get_value(unsigned gpio)
+{
+	u32 val;
+
+	if (gpio_get_direction(gpio) == GPIO_DIRECTION_OUT)
+		val = gpio_get_output_value(gpio);
+	else
+		val = gpio_get_input_value(gpio);
+
+	return val;
+}
+
+/* Set output value */
+static int gpio_set_output_value(unsigned gpio, int value)
+{
+	u32 val, gpio_priv;
+	struct gpio_regs *regs;
+	struct xilinx_gpio_priv *priv = gpio_get_controller(gpio);
+
+	if (priv) {
+		regs = priv->regs;
+		gpio_priv = gpio - priv->gpio_min;
+		val = priv->gpiodata_store;
+		if (value)
+			val |= 1 << gpio_priv;
+		else
+			val &= ~(1 << gpio_priv);
+
+		writel(val, &regs->gpiodata);
+		debug("%s: reg: %x, gpio_no: %d, output_val: %d\n", __func__,
+		      (u32)priv->regs, gpio_priv, val);
+		priv->gpiodata_store = val;
+
+		return 0;
+	}
+
+	return -1;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	if (gpio_get_direction(gpio) == GPIO_DIRECTION_OUT)
+		return gpio_set_output_value(gpio, value);
+
+	return -1;
+}
+
+/* Set GPIO as input */
+int gpio_direction_input(unsigned gpio)
+{
+	debug("%s\n", __func__);
+	return gpio_set_direction(gpio, GPIO_DIRECTION_IN);
+}
+
+/* Setup GPIO as output and set output value */
+int gpio_direction_output(unsigned gpio, int value)
+{
+	int ret = gpio_set_direction(gpio, GPIO_DIRECTION_OUT);
+
+	debug("%s\n", __func__);
+
+	if (ret < 0)
+		return ret;
+
+	return gpio_set_output_value(gpio, value);
+}
+
+/* Show gpio status */
+void gpio_info(void)
+{
+	unsigned gpio;
+
+	struct list_head *entry;
+	struct xilinx_gpio_priv *priv = NULL;
+
+	list_for_each(entry, &gpio_list) {
+		priv = list_entry(entry, struct xilinx_gpio_priv, list);
+		printf("\n%s: %s/%x (%d-%d)\n", __func__, priv->name,
+		       (u32)priv->regs, priv->gpio_min, priv->gpio_max);
+
+		for (gpio = priv->gpio_min; gpio <= priv->gpio_max; gpio++) {
+			printf("GPIO_%d:\t%s is an ", gpio, get_name(gpio));
+			if (gpio_get_direction(gpio) == GPIO_DIRECTION_OUT)
+				printf("OUTPUT value = %d\n",
+				       gpio_get_output_value(gpio));
+			else
+				printf("INPUT value = %d\n",
+				       gpio_get_input_value(gpio));
+		}
+	}
+}
+
+int gpio_request(unsigned gpio, const char *label)
+{
+	u32 gpio_priv;
+	struct xilinx_gpio_priv *priv;
+
+	if (gpio >= xilinx_gpio_max)
+		return -EINVAL;
+
+	priv = gpio_get_controller(gpio);
+	if (priv) {
+		gpio_priv = gpio - priv->gpio_min;
+
+		if (label != NULL) {
+			strncpy(priv->gpio_name[gpio_priv].name, label,
+				GPIO_NAME_SIZE);
+			priv->gpio_name[gpio_priv].name[GPIO_NAME_SIZE - 1] =
+					'\0';
+		}
+		return 0;
+	}
+
+	return -1;
+}
+
+int gpio_free(unsigned gpio)
+{
+	u32 gpio_priv;
+	struct xilinx_gpio_priv *priv;
+
+	if (gpio >= xilinx_gpio_max)
+		return -EINVAL;
+
+	priv = gpio_get_controller(gpio);
+	if (priv) {
+		gpio_priv = gpio - priv->gpio_min;
+		priv->gpio_name[gpio_priv].name[0] = '\0';
+
+		/* Do nothing here */
+		return 0;
+	}
+
+	return -1;
+}
+
+int gpio_alloc(u32 baseaddr, const char *name, u32 gpio_no)
+{
+	struct xilinx_gpio_priv *priv;
+
+	priv = calloc(1, sizeof(struct xilinx_gpio_priv));
+
+	/* Setup gpio name */
+	if (name != NULL) {
+		strncpy(priv->name, name, GPIO_NAME_SIZE);
+		priv->name[GPIO_NAME_SIZE - 1] = '\0';
+	}
+	priv->regs = (struct gpio_regs *)baseaddr;
+
+	priv->gpio_min = xilinx_gpio_max;
+	xilinx_gpio_max = priv->gpio_min + gpio_no;
+	priv->gpio_max = xilinx_gpio_max - 1;
+
+	priv->gpio_name = calloc(gpio_no, sizeof(struct gpio_names));
+
+	INIT_LIST_HEAD(&priv->list);
+	list_add_tail(&priv->list, &gpio_list);
+
+	printf("%s: Add %s (%d-%d)\n", __func__, name,
+	       priv->gpio_min, priv->gpio_max);
+
+	/* Return the first gpio allocated for this device */
+	return priv->gpio_min;
+}
+
+/* Dual channel gpio is one IP with two independent channels */
+int gpio_alloc_dual(u32 baseaddr, const char *name, u32 gpio_no0, u32 gpio_no1)
+{
+	int ret;
+
+	ret = gpio_alloc(baseaddr, name, gpio_no0);
+	gpio_alloc(baseaddr + 8, strcat((char *)name, "_1"), gpio_no1);
+
+	/* Return the first gpio allocated for this device */
+	return ret;
+}