x86: gpio: Add GPIO driver for Intel ICH6 and later.

Implement <asm-generic/gpio.h> functions for Intel ICH6 and later.
Only GPIOs 0-31 are handled by this code.

Signed-off-by: Bill Richardson <wfrichar@chromium.org>

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 243 insertions, 0 deletions

diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index d50ac3b..2d97b4f 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -26,6 +26,7 @@ include $(TOPDIR)/config.mk
 LIB 	:= $(obj)libgpio.o
 
 COBJS-$(CONFIG_AT91_GPIO)	+= at91_gpio.o
+COBJS-$(CONFIG_INTEL_ICH6_GPIO)	+= intel_ich6_gpio.o
 COBJS-$(CONFIG_KIRKWOOD_GPIO)	+= kw_gpio.o
 COBJS-$(CONFIG_MARVELL_GPIO)	+= mvgpio.o
 COBJS-$(CONFIG_MARVELL_MFP)	+= mvmfp.o
diff --git a/drivers/gpio/intel_ich6_gpio.c b/drivers/gpio/intel_ich6_gpio.c
new file mode 100644
index 0000000..1ccb641
--- /dev/null
+++ b/drivers/gpio/intel_ich6_gpio.c
@@ -0,0 +1,242 @@
+/*
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * 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
+ */
+
+/*
+ * This is a GPIO driver for Intel ICH6 and later. The x86 GPIOs are accessed
+ * through the PCI bus. Each PCI device has 256 bytes of configuration space,
+ * consisting of a standard header and a device-specific set of registers. PCI
+ * bus 0, device 31, function 0 gives us access to the chipset GPIOs (among
+ * other things). Within the PCI configuration space, the GPIOBASE register
+ * tells us where in the device's I/O region we can find more registers to
+ * actually access the GPIOs.
+ *
+ * PCI bus/device/function 0:1f:0  => PCI config registers
+ *   PCI config register "GPIOBASE"
+ *     PCI I/O space + [GPIOBASE]  => start of GPIO registers
+ *       GPIO registers => gpio pin function, direction, value
+ */
+
+#include <common.h>
+#include <pci.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+
+/* Where in config space is the register that points to the GPIO registers? */
+#define PCI_CFG_GPIOBASE 0x48
+
+/*
+ * There are often more than 32 GPIOs, depending on the ICH version.
+ * For now, we just support bank 0 because it's the same for all.
+ */
+#define GPIO_MAX 31
+
+/* Within the I/O space, where are the registers to control the GPIOs? */
+#define OFS_GPIO_USE_SEL 0x00
+#define OFS_GPIO_IO_SEL  0x04
+#define OFS_GP_LVL       0x0C
+
+static pci_dev_t dev;				/* handle for 0:1f:0 */
+static u32 gpiobase;				/* offset into I/O space */
+static int found_it_once;			/* valid GPIO device? */
+static int in_use[GPIO_MAX];			/* "lock" for access to pins */
+
+static int gpio_init(void)
+{
+	u8 tmpbyte;
+	u16 tmpword;
+	u32 tmplong;
+
+	/* Have we already done this? */
+	if (found_it_once)
+		return 0;
+
+	/* Where should it be? */
+	dev = PCI_BDF(0, 0x1f, 0);
+
+	/* Is the device present? */
+	pci_read_config_word(dev, PCI_VENDOR_ID, &tmpword);
+	if (tmpword != PCI_VENDOR_ID_INTEL) {
+		debug("%s: wrong VendorID\n", __func__);
+		return -1;
+	}
+	/*
+	 * We'd like to check the Device ID too, but pretty much any
+	 * value is either a) correct with slight differences, or b)
+	 * correct but undocumented. We'll have to check other things
+	 * instead...
+	 */
+
+	/* I/O should already be enabled (it's a RO bit). */
+	pci_read_config_word(dev, PCI_COMMAND, &tmpword);
+	if (!(tmpword & PCI_COMMAND_IO)) {
+		debug("%s: device IO not enabled\n", __func__);
+		return -1;
+	}
+
+	/* Header Type must be normal (bits 6-0 only; see spec.) */
+	pci_read_config_byte(dev, PCI_HEADER_TYPE, &tmpbyte);
+	if ((tmpbyte & 0x7f) != PCI_HEADER_TYPE_NORMAL) {
+		debug("%s: invalid Header type\n", __func__);
+		return -1;
+	}
+
+	/* Base Class must be a bridge device */
+	pci_read_config_byte(dev, PCI_CLASS_CODE, &tmpbyte);
+	if (tmpbyte != PCI_CLASS_CODE_BRIDGE) {
+		debug("%s: invalid class\n", __func__);
+		return -1;
+	}
+	/* Sub Class must be ISA */
+	pci_read_config_byte(dev, PCI_CLASS_SUB_CODE, &tmpbyte);
+	if (tmpbyte != PCI_CLASS_SUB_CODE_BRIDGE_ISA) {
+		debug("%s: invalid subclass\n", __func__);
+		return -1;
+	}
+
+	/* Programming Interface must be 0x00 (no others exist) */
+	pci_read_config_byte(dev, PCI_CLASS_PROG, &tmpbyte);
+	if (tmpbyte != 0x00) {
+		debug("%s: invalid interface type\n", __func__);
+		return -1;
+	}
+
+	/*
+	 * GPIOBASE moved to its current offset with ICH6, but prior to
+	 * that it was unused (or undocumented). Check that it looks
+	 * okay: not all ones or zeros, and mapped to I/O space (bit 0).
+	 */
+	pci_read_config_dword(dev, PCI_CFG_GPIOBASE, &tmplong);
+	if (tmplong == 0x00000000 || tmplong == 0xffffffff ||
+	    !(tmplong & 0x00000001)) {
+		debug("%s: unexpected GPIOBASE value\n", __func__);
+		return -1;
+	}
+
+	/*
+	 * Okay, I guess we're looking at the right device. The actual
+	 * GPIO registers are in the PCI device's I/O space, starting
+	 * at the offset that we just read. Bit 0 indicates that it's
+	 * an I/O address, not a memory address, so mask that off.
+	 */
+	gpiobase = tmplong & 0xfffffffe;
+
+	/* Finally. These are the droids we're looking for. */
+	found_it_once = 1;
+	return 0;
+}
+
+int gpio_request(unsigned gpio, const char *label /* UNUSED */)
+{
+	u32 tmplong;
+
+	/* Are we doing it wrong? */
+	if (gpio > GPIO_MAX || in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+
+	/* Is the hardware ready? */
+	if (gpio_init()) {
+		debug("%s: gpio_init failed\n", __func__);
+		return -1;
+	}
+
+	/*
+	 * Make sure that the GPIO pin we want isn't already in use for some
+	 * built-in hardware function. We have to check this for every
+	 * requested pin.
+	 */
+	tmplong = inl(gpiobase + OFS_GPIO_USE_SEL);
+	if (!(tmplong & (1UL << gpio))) {
+		debug("%s: reserved for internal use\n", __func__);
+		return -1;
+	}
+
+	in_use[gpio] = 1;
+	return 0;
+}
+
+int gpio_free(unsigned gpio)
+{
+	if (gpio > GPIO_MAX || !in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+	in_use[gpio] = 0;
+	return 0;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+	u32 tmplong;
+
+	if (gpio > GPIO_MAX || !in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+	tmplong = inl(gpiobase + OFS_GPIO_IO_SEL);
+	tmplong |= (1UL << gpio);
+	outl(gpiobase + OFS_GPIO_IO_SEL, tmplong);
+	return 0;
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+	u32 tmplong;
+
+	if (gpio > GPIO_MAX || !in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+	tmplong = inl(gpiobase + OFS_GPIO_IO_SEL);
+	tmplong &= ~(1UL << gpio);
+	outl(gpiobase + OFS_GPIO_IO_SEL, tmplong);
+	return 0;
+}
+
+int gpio_get_value(unsigned gpio)
+{
+	u32 tmplong;
+
+	if (gpio > GPIO_MAX || !in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+	tmplong = inl(gpiobase + OFS_GP_LVL);
+	return (tmplong & (1UL << gpio)) ? 1 : 0;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+	u32 tmplong;
+
+	if (gpio > GPIO_MAX || !in_use[gpio]) {
+		debug("%s: gpio unavailable\n", __func__);
+		return -1;
+	}
+	tmplong = inl(gpiobase + OFS_GP_LVL);
+	if (value)
+		tmplong |= (1UL << gpio);
+	else
+		tmplong &= ~(1UL << gpio);
+	outl(gpiobase + OFS_GP_LVL, tmplong);
+	return 0;
+}