am335x: Add some code for manipulating GPIOs

Add code for manipulating the GPIOs on the am335x. The API is patterned after
the one used for the Exynos SOCs.

Change-Id: I275317304bd0682f348f72f1c77ed5613065af3f
Signed-off-by: Gabe Black <gabeblack@chromium.org>
Reviewed-on: https://review.coreboot.org/3942
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/cpu/ti/am335x/Makefile.inc

@@ -1,6 +1,7 @@
 bootblock-y	+= bootblock.c
 bootblock-y	+= bootblock_media.c
 bootblock-y	+= dmtimer.c
+bootblock-y	+= gpio.c
 bootblock-y	+= pinmux.c
 
 romstage-y	+= nand.c

src/cpu/ti/am335x/gpio.c

@@ -0,0 +1,89 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * 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.
+ */
+
+#include <arch/io.h>
+#include <console/console.h>
+#include <cpu/ti/am335x/gpio.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+static struct am335x_gpio_regs *gpio_regs_and_bit(unsigned gpio, uint32_t *bit)
+{
+	unsigned bank = gpio / AM335X_GPIO_BITS_PER_BANK;
+
+	if (bank > ARRAY_SIZE(am335x_gpio_banks)) {
+		printk(BIOS_ERR, "Bad gpio index %d.\n", gpio);
+		return NULL;
+	}
+	*bit = 1 << (gpio % 32);
+	return am335x_gpio_banks[bank];
+}
+
+void am335x_disable_gpio_irqs(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(am335x_gpio_banks); i++)
+		write32(&am335x_gpio_banks[i]->irqstatus_clr_0, 0xffffffff);
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	uint32_t bit;
+	struct am335x_gpio_regs *regs = gpio_regs_and_bit(gpio, &bit);
+
+	if (!regs)
+		return -1;
+	setbits_le32(&regs->oe, bit);
+	return 0;
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	uint32_t bit;
+	struct am335x_gpio_regs *regs = gpio_regs_and_bit(gpio, &bit);
+
+	if (!regs)
+		return -1;
+	if (value)
+		write32(&regs->setdataout, bit);
+	else
+		write32(&regs->cleardataout, bit);
+	clrbits_le32(&regs->oe, bit);
+	return 0;
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	uint32_t bit;
+	struct am335x_gpio_regs *regs = gpio_regs_and_bit(gpio, &bit);
+
+	if (!regs)
+		return -1;
+	return (read32(&regs->datain) & bit) ? 1 : 0;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	uint32_t bit;
+	struct am335x_gpio_regs *regs = gpio_regs_and_bit(gpio, &bit);
+
+	if (!regs)
+		return -1;
+	if (value)
+		write32(&regs->setdataout, bit);
+	else
+		write32(&regs->cleardataout, bit);
+	return 0;
+}

src/cpu/ti/am335x/gpio.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * 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.
+ */
+
+#ifndef __CPU_TI_AM335X_GPIO_H__
+#define __CPU_TI_AM335X_GPIO_H__
+
+#include <stdint.h>
+
+enum {
+	AM335X_GPIO_BITS_PER_BANK = 32
+};
+
+struct am335x_gpio_regs {
+	uint32_t revision;		// 0x0
+	uint8_t _rsv0[0xc];		// 0x4-0xf
+	uint32_t sysconfig;		// 0x10
+	uint8_t _rsv1[0xc];		// 0x14-0x1f
+	uint32_t eoi;			// 0x20
+	uint32_t irqstatus_raw_0;	// 0x24
+	uint32_t irqstatus_raw_1;	// 0x28
+	uint32_t irqstatus_0;		// 0x2c
+	uint32_t irqstatus_1;		// 0x30
+	uint32_t irqstatus_set_0;	// 0x34
+	uint32_t irqstatus_set_1;	// 0x38
+	uint32_t irqstatus_clr_0;	// 0x3c
+	uint32_t irqstatus_clk_1;	// 0x40
+	uint32_t irqwaken_0;		// 0x44
+	uint32_t irqwaken_1;		// 0x48
+	uint8_t _rsv2[0xc8];		// 0x4c-0x113
+	uint32_t sysstatus;		// 0x114
+	uint8_t _rsv3[0x18];		// 0x118-0x12f
+	uint32_t ctrl;			// 0x130
+	uint32_t oe;			// 0x134
+	uint32_t datain;		// 0x138
+	uint32_t dataout;		// 0x13c
+	uint32_t leveldetect0;		// 0x140
+	uint32_t leveldetect1;		// 0x144
+	uint32_t risingdetect;		// 0x148
+	uint32_t fallingdetect;		// 0x14c
+	uint32_t debouncenable;		// 0x150
+	uint32_t debouncingtime;	// 0x154
+	uint8_t _rsv4[0x38];		// 0x158-0x18f
+	uint32_t cleardataout;		// 0x190
+	uint32_t setdataout;		// 0x194
+} __attribute__((packed));
+
+static struct am335x_gpio_regs * const am335x_gpio_banks[] = {
+	(void *)0x44e07000, (void *)0x4804c000,
+	(void *)0x481ac000, (void *)0x481ae000
+};
+
+void am335x_disable_gpio_irqs(void);
+
+int gpio_direction_input(unsigned gpio);
+int gpio_direction_output(unsigned gpio, int value);
+int gpio_get_value(unsigned gpio);
+int gpio_set_value(unsigned gpio, int value);
+
+#endif	/* __CPU_TI_AM335X_CLOCK_H__ */