[PATCH v2 2/3] gpio: Add gpio driver support for ThunderX and OCTEON-TX

[David Daney]

From: David Daney <david.daney@xxxxxxxxxx>

Cavium ThunderX and OCTEON-TX are arm64 based SoCs.  Add driver for
the on-chip GPIO pins.

Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
---
 drivers/gpio/Kconfig         |   8 +
 drivers/gpio/Makefile        |   1 +
 drivers/gpio/gpio-thunderx.c | 487 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 496 insertions(+)
 create mode 100644 drivers/gpio/gpio-thunderx.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index d5d3654..e691a5e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -421,6 +421,14 @@ config GPIO_TS4800
 	help
 	  This driver support TS-4800 FPGA GPIO controllers.
 
+config GPIO_THUNDERX
+	tristate "Cavium ThunderX/OCTEON-TX GPIO"
+	depends on ARCH_THUNDER || (64BIT && COMPILE_TEST)
+	select GPIOLIB_IRQCHIP
+	help
+	  Say yes here to support the on-chip GPIO lines on the ThunderX
+	  and OCTEON-TX families of SoCs.
+
 config GPIO_TZ1090
 	bool "Toumaz Xenif TZ1090 GPIO support"
 	depends on SOC_TZ1090
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a7676b8..c62bc72 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -108,6 +108,7 @@ obj-$(CONFIG_GPIO_SYSCON)	+= gpio-syscon.o
 obj-$(CONFIG_GPIO_TB10X)	+= gpio-tb10x.o
 obj-$(CONFIG_GPIO_TC3589X)	+= gpio-tc3589x.o
 obj-$(CONFIG_GPIO_TEGRA)	+= gpio-tegra.o
+obj-$(CONFIG_GPIO_THUNDERX)	+= gpio-thunderx.o
 obj-$(CONFIG_GPIO_TIMBERDALE)	+= gpio-timberdale.o
 obj-$(CONFIG_GPIO_PALMAS)	+= gpio-palmas.o
 obj-$(CONFIG_GPIO_TPIC2810)	+= gpio-tpic2810.o
diff --git a/drivers/gpio/gpio-thunderx.c b/drivers/gpio/gpio-thunderx.c
new file mode 100644
index 0000000..089d8d4
--- /dev/null
+++ b/drivers/gpio/gpio-thunderx.c
@@ -0,0 +1,487 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2016, 2017 Cavium Inc.
+ */
+
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+
+
+#define GPIO_RX_DAT	0x0
+#define GPIO_TX_SET	0x8
+#define GPIO_TX_CLR	0x10
+#define GPIO_CONST	0x90
+#define  GPIO_CONST_GPIOS_MASK 0xff
+#define GPIO_BIT_CFG	0x400
+#define  GPIO_BIT_CFG_TX_OE		BIT(0)
+#define  GPIO_BIT_CFG_PIN_XOR		BIT(1)
+#define  GPIO_BIT_CFG_INT_EN		BIT(2)
+#define  GPIO_BIT_CFG_INT_TYPE		BIT(3)
+#define  GPIO_BIT_CFG_FIL_CNT_SHIFT	4
+#define  GPIO_BIT_CFG_FIL_SEL_SHIFT	8
+#define  GPIO_BIT_CFG_TX_OD		BIT(12)
+#define  GPIO_BIT_CFG_PIN_SEL_MASK	GENMASK(25, 16)
+#define GPIO_INTR	0x800
+#define  GPIO_INTR_INTR			BIT(0)
+#define  GPIO_INTR_INTR_W1S		BIT(1)
+#define  GPIO_INTR_ENA_W1C		BIT(2)
+#define  GPIO_INTR_ENA_W1S		BIT(3)
+#define GPIO_2ND_BANK	0x1400
+
+#define GLITCH_FILTER_400NS ((4ull << GPIO_BIT_CFG_FIL_SEL_SHIFT) | \
+			     (9ull << GPIO_BIT_CFG_FIL_CNT_SHIFT))
+
+static unsigned int bit_cfg_reg(unsigned int line)
+{
+	return 8 * line + GPIO_BIT_CFG;
+}
+
+static unsigned int intr_reg(unsigned int line)
+{
+	return 8 * line + GPIO_INTR;
+}
+
+struct thunderx_gpio;
+
+struct thunderx_irqdev {
+	struct thunderx_gpio	*gpio;
+	char			*name;
+	unsigned int		line;
+};
+
+struct thunderx_gpio {
+	struct gpio_chip	chip;
+	u8 __iomem		*register_base;
+	struct msix_entry	*msix_entries;
+	struct thunderx_irqdev	*irqdev_entries;
+	raw_spinlock_t		lock;
+	unsigned long		invert_mask[2];
+	unsigned long		od_mask[2];
+	int			base_msi;
+};
+
+
+/*
+ * Check (and WARN) that the pin is available for GPIO.  We will not
+ * allow modification of the state of non-GPIO pins from this driver.
+ */
+static bool thunderx_gpio_is_gpio(struct thunderx_gpio *gpio,
+				  unsigned int line)
+{
+	u64 bit_cfg = readq(gpio->register_base + bit_cfg_reg(line));
+	bool rv = (bit_cfg & GPIO_BIT_CFG_PIN_SEL_MASK) == 0;
+
+	WARN_RATELIMIT(!rv, "Pin %d not available for GPIO\n", line);
+
+	return rv;
+}
+
+static int thunderx_gpio_dir_in(struct gpio_chip *chip, unsigned int line)
+{
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+
+	if (!thunderx_gpio_is_gpio(gpio, line))
+		return -EIO;
+
+	raw_spin_lock(&gpio->lock);
+	clear_bit(line, gpio->invert_mask);
+	clear_bit(line, gpio->od_mask);
+	writeq(GLITCH_FILTER_400NS, gpio->register_base + bit_cfg_reg(line));
+	raw_spin_unlock(&gpio->lock);
+	return 0;
+}
+
+static void thunderx_gpio_set(struct gpio_chip *chip, unsigned int line,
+			      int value)
+{
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	int bank = line / 64;
+	int bank_bit = line % 64;
+
+	void __iomem *reg = gpio->register_base +
+		(bank * GPIO_2ND_BANK) + (value ? GPIO_TX_SET : GPIO_TX_CLR);
+
+	writeq(1ull << bank_bit, reg);
+}
+
+static int thunderx_gpio_dir_out(struct gpio_chip *chip, unsigned int line,
+				 int value)
+{
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	u64 bit_cfg = GPIO_BIT_CFG_TX_OE;
+
+	if (!thunderx_gpio_is_gpio(gpio, line))
+		return -EIO;
+
+	raw_spin_lock(&gpio->lock);
+
+	thunderx_gpio_set(chip, line, value);
+
+	if (test_bit(line, gpio->invert_mask))
+		bit_cfg |= GPIO_BIT_CFG_PIN_XOR;
+
+	if (test_bit(line, gpio->od_mask))
+		bit_cfg |= GPIO_BIT_CFG_TX_OD;
+
+	writeq(bit_cfg, gpio->register_base + bit_cfg_reg(line));
+
+	raw_spin_unlock(&gpio->lock);
+	return 0;
+}
+
+/*
+ * Weird, setting open-drain mode causes signal inversion.  Note this
+ * so we can compensate in the dir_out function.
+ */
+static int thunderx_gpio_set_single_ended(struct gpio_chip *chip,
+					  unsigned int line,
+					  enum single_ended_mode mode)
+{
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+
+	if (mode == LINE_MODE_OPEN_SOURCE)
+		return -ENOTSUPP;
+
+	if (!thunderx_gpio_is_gpio(gpio, line))
+		return -EIO;
+
+	raw_spin_lock(&gpio->lock);
+	if (mode == LINE_MODE_OPEN_DRAIN) {
+		set_bit(line, gpio->invert_mask);
+		set_bit(line, gpio->od_mask);
+	} else {
+		clear_bit(line, gpio->invert_mask);
+		clear_bit(line, gpio->od_mask);
+	}
+	raw_spin_unlock(&gpio->lock);
+
+	return 0;
+}
+
+static int thunderx_gpio_get(struct gpio_chip *chip, unsigned int line)
+{
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	int bank = line / 64;
+	int bank_bit = line % 64;
+	u64 read_bits = readq(gpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_RX_DAT);
+
+	read_bits >>= bank_bit;
+
+	if (test_bit(line, gpio->invert_mask))
+		return !(read_bits & 1);
+	else
+		return read_bits & 1;
+}
+
+static void thunderx_gpio_set_multiple(struct gpio_chip *chip,
+				       unsigned long *mask,
+				       unsigned long *bits)
+{
+	int bank;
+	u64 set_bits, clear_bits;
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+
+	for (bank = 0; bank <= chip->ngpio / 64; bank++) {
+		set_bits = bits[bank] & mask[bank];
+		clear_bits = ~bits[bank] & mask[bank];
+		writeq(set_bits, gpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_TX_SET);
+		writeq(clear_bits, gpio->register_base + (bank * GPIO_2ND_BANK) + GPIO_TX_CLR);
+	}
+}
+
+static irqreturn_t thunderx_gpio_chain_handler(int irq, void *dev)
+{
+	struct thunderx_irqdev *irqdev = dev;
+	int chained_irq;
+	int ret;
+
+	chained_irq = irq_find_mapping(irqdev->gpio->chip.irqdomain,
+				       irqdev->line);
+	if (!chained_irq)
+		return IRQ_NONE;
+
+	ret = generic_handle_irq(chained_irq);
+
+	return ret ? IRQ_NONE : IRQ_HANDLED;
+}
+
+static int thunderx_gpio_irq_request_resources(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+	struct thunderx_irqdev *irqdev;
+	int err;
+
+	if (!thunderx_gpio_is_gpio(gpio, line))
+		return -EIO;
+
+	irqdev = gpio->irqdev_entries + line;
+
+	irqdev->gpio = gpio;
+	irqdev->line = line;
+	irqdev->name = devm_kasprintf(chip->parent, GFP_KERNEL,
+				      "gpio-%d", line + chip->base);
+
+	writeq(GPIO_INTR_ENA_W1C, gpio->register_base + intr_reg(line));
+
+	err = devm_request_irq(chip->parent, gpio->msix_entries[line].vector,
+			       thunderx_gpio_chain_handler, IRQF_NO_THREAD, irqdev->name, irqdev);
+	return err;
+}
+
+static void thunderx_gpio_irq_release_resources(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+	struct thunderx_irqdev *irqdev;
+
+	irqdev = gpio->irqdev_entries + line;
+
+	/*
+	 * The request_resources/release_resources functions may be
+	 * called multiple times in the lifitime of the driver, so we
+	 * need to clean up the devm_* things to avoid a resource
+	 * leak.
+	 */
+	devm_free_irq(chip->parent, gpio->msix_entries[line].vector, irqdev);
+
+	writeq(GPIO_INTR_ENA_W1C, gpio->register_base + intr_reg(line));
+
+	devm_kfree(chip->parent, irqdev->name);
+}
+
+static void thunderx_gpio_irq_ack(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+
+	writeq(GPIO_INTR_INTR,
+	       gpio->register_base + intr_reg(line));
+}
+
+static void thunderx_gpio_irq_mask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+
+	writeq(GPIO_INTR_ENA_W1C, gpio->register_base + intr_reg(line));
+}
+
+static void thunderx_gpio_irq_mask_ack(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+
+	writeq(GPIO_INTR_ENA_W1C | GPIO_INTR_INTR,
+	       gpio->register_base + intr_reg(line));
+}
+
+static void thunderx_gpio_irq_unmask(struct irq_data *data)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+
+	writeq(GPIO_INTR_ENA_W1S, gpio->register_base + intr_reg(line));
+}
+
+static int thunderx_gpio_irq_set_type(struct irq_data *data,
+				      unsigned int flow_type)
+{
+	struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+	struct thunderx_gpio *gpio = container_of(chip, struct thunderx_gpio, chip);
+	unsigned int line = data->hwirq;
+	u64 bit_cfg;
+
+	irqd_set_trigger_type(data, flow_type);
+
+	bit_cfg = GLITCH_FILTER_400NS | GPIO_BIT_CFG_INT_EN;
+
+	if (flow_type & IRQ_TYPE_EDGE_BOTH) {
+		irq_set_handler_locked(data, handle_edge_irq);
+		bit_cfg |= GPIO_BIT_CFG_INT_TYPE;
+	} else {
+		irq_set_handler_locked(data, handle_level_irq);
+	}
+
+	raw_spin_lock(&gpio->lock);
+	if (flow_type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_LEVEL_LOW)) {
+		bit_cfg |= GPIO_BIT_CFG_PIN_XOR;
+		set_bit(line, gpio->invert_mask);
+	} else {
+		clear_bit(line, gpio->invert_mask);
+	}
+	clear_bit(line, gpio->od_mask);
+	writeq(bit_cfg, gpio->register_base + bit_cfg_reg(line));
+	raw_spin_unlock(&gpio->lock);
+
+	return IRQ_SET_MASK_OK;
+}
+
+/*
+ * Interrupts are chained from underlying MSI-X vectors.  We have
+ * these irq_chip functions to be able to handle level triggering
+ * semantics and other acknowledgment tasks associated with the GPIO
+ * mechanism.
+ */
+static struct irq_chip thunderx_gpio_irq_chip = {
+	.name			= "GPIO",
+	.irq_enable		= thunderx_gpio_irq_unmask,
+	.irq_disable		= thunderx_gpio_irq_mask,
+	.irq_ack		= thunderx_gpio_irq_ack,
+	.irq_mask		= thunderx_gpio_irq_mask,
+	.irq_mask_ack		= thunderx_gpio_irq_mask_ack,
+	.irq_unmask		= thunderx_gpio_irq_unmask,
+	.irq_set_type		= thunderx_gpio_irq_set_type,
+	.irq_request_resources	= thunderx_gpio_irq_request_resources,
+	.irq_release_resources	= thunderx_gpio_irq_release_resources,
+	.flags			= IRQCHIP_SET_TYPE_MASKED
+};
+
+static int thunderx_gpio_probe(struct pci_dev *pdev,
+			       const struct pci_device_id *id)
+{
+	void __iomem * const *tbl;
+	struct device *dev = &pdev->dev;
+	struct thunderx_gpio *gpio;
+	struct gpio_chip *chip;
+	int ngpio, i;
+	int err = 0;
+
+	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	raw_spin_lock_init(&gpio->lock);
+	chip = &gpio->chip;
+
+	pci_set_drvdata(pdev, gpio);
+
+	err = pcim_enable_device(pdev);
+	if (err) {
+		dev_err(dev, "Failed to enable PCI device: err %d\n", err);
+		goto out;
+	}
+
+	err = pcim_iomap_regions(pdev, 1 << 0, KBUILD_MODNAME);
+	if (err) {
+		dev_err(dev, "Failed to iomap PCI device: err %d\n", err);
+		goto out;
+	}
+
+	tbl = pcim_iomap_table(pdev);
+	gpio->register_base = tbl[0];
+	if (!gpio->register_base) {
+		dev_err(dev, "Cannot map PCI resource\n");
+		err = -ENOMEM;
+		goto out;
+	}
+
+	if (pdev->subsystem_device == 0xa10a) {
+		/* CN88XX has no GPIO_CONST register*/
+		ngpio = 50;
+		gpio->base_msi = 48;
+	} else {
+		u64 c = readq(gpio->register_base + GPIO_CONST);
+
+		ngpio = c & GPIO_CONST_GPIOS_MASK;
+		gpio->base_msi = (c >> 8) & 0xff;
+	}
+
+	gpio->msix_entries = devm_kzalloc(dev,
+					  sizeof(struct msix_entry) * ngpio,
+					  GFP_KERNEL);
+	if (!gpio->msix_entries) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	gpio->irqdev_entries = devm_kzalloc(dev,
+					    sizeof(struct thunderx_irqdev) * ngpio,
+					    GFP_KERNEL);
+	if (!gpio->irqdev_entries) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < ngpio; i++)
+		gpio->msix_entries[i].entry = gpio->base_msi + (2 * i);
+
+	err = pci_enable_msix(pdev, gpio->msix_entries, ngpio);
+	if (err < 0)
+		goto out;
+
+	chip->label = KBUILD_MODNAME;
+	chip->parent = dev;
+	chip->owner = THIS_MODULE;
+	chip->base = -1; /* System allocated */
+	chip->can_sleep = false;
+	chip->ngpio = ngpio;
+	chip->direction_input = thunderx_gpio_dir_in;
+	chip->get = thunderx_gpio_get;
+	chip->direction_output = thunderx_gpio_dir_out;
+	chip->set = thunderx_gpio_set;
+	chip->set_multiple = thunderx_gpio_set_multiple;
+	chip->set_single_ended = thunderx_gpio_set_single_ended;
+	err = gpiochip_add(chip);
+	if (err)
+		goto out;
+
+	err = gpiochip_irqchip_add(chip, &thunderx_gpio_irq_chip, 0,
+				   handle_level_irq, IRQ_TYPE_NONE);
+	if (err) {
+		dev_err(dev, "gpiochip_irqchip_add failed: %d\n", err);
+		goto irqchip_out;
+	}
+
+	dev_info(dev, "ThunderX GPIO: %d lines with base %d.\n",
+		 ngpio, chip->base);
+	return 0;
+
+irqchip_out:
+	gpiochip_remove(chip);
+out:
+	pci_set_drvdata(pdev, NULL);
+	return err;
+}
+
+static void thunderx_gpio_remove(struct pci_dev *pdev)
+{
+	struct thunderx_gpio *gpio = pci_get_drvdata(pdev);
+
+	gpiochip_remove(&gpio->chip);
+	pci_set_drvdata(pdev, NULL);
+}
+
+static const struct pci_device_id thunderx_gpio_id_table[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_CAVIUM, 0xA00A) },
+	{ 0, }	/* end of table */
+};
+
+MODULE_DEVICE_TABLE(pci, thunderx_gpio_id_table);
+
+static struct pci_driver thunderx_gpio_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = thunderx_gpio_id_table,
+	.probe = thunderx_gpio_probe,
+	.remove = thunderx_gpio_remove,
+};
+
+module_pci_driver(thunderx_gpio_driver);
+
+MODULE_DESCRIPTION("Cavium Inc. ThunderX/OCTEON-TX GPIO Driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.1