IB/core: Add mitigation for Spectre V1

[linux/fpc-iii.git] / drivers / gpio / gpio-lynxpoint.c

/*
 * GPIO controller driver for Intel Lynxpoint PCH chipset>
 * Copyright (c) 2012, Intel Corporation.
 *
 * Author: Mathias Nyman <mathias.nyman@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/io.h>

/* LynxPoint chipset has support for 94 gpio pins */

#define LP_NUM_GPIO     94

/* Bitmapped register offsets */
#define LP_ACPI_OWNED   0x00 /* Bitmap, set by bios, 0: pin reserved for ACPI */
#define LP_GC           0x7C /* set APIC IRQ to IRQ14 or IRQ15 for all pins */
#define LP_INT_STAT     0x80
#define LP_INT_ENABLE   0x90

/* Each pin has two 32 bit config registers, starting at 0x100 */
#define LP_CONFIG1      0x100
#define LP_CONFIG2      0x104

/* LP_CONFIG1 reg bits */
#define OUT_LVL_BIT     BIT(31)
#define IN_LVL_BIT      BIT(30)
#define TRIG_SEL_BIT    BIT(4) /* 0: Edge, 1: Level */
#define INT_INV_BIT     BIT(3) /* Invert interrupt triggering */
#define DIR_BIT         BIT(2) /* 0: Output, 1: Input */
#define USE_SEL_BIT     BIT(0) /* 0: Native, 1: GPIO */

/* LP_CONFIG2 reg bits */
#define GPINDIS_BIT     BIT(2) /* disable input sensing */
#define GPIWP_BIT       (BIT(0) | BIT(1)) /* weak pull options */

struct lp_gpio {
        struct gpio_chip        chip;
        struct platform_device  *pdev;
        spinlock_t              lock;
        unsigned long           reg_base;
};

/*
 * Lynxpoint gpios are controlled through both bitmapped registers and
 * per gpio specific registers. The bitmapped registers are in chunks of
 * 3 x 32bit registers to cover all 94 gpios
 *
 * per gpio specific registers consist of two 32bit registers per gpio
 * (LP_CONFIG1 and LP_CONFIG2), with 94 gpios there's a total of
 * 188 config registers.
 *
 * A simplified view of the register layout look like this:
 *
 * LP_ACPI_OWNED[31:0] gpio ownerships for gpios 0-31  (bitmapped registers)
 * LP_ACPI_OWNED[63:32] gpio ownerships for gpios 32-63
 * LP_ACPI_OWNED[94:64] gpio ownerships for gpios 63-94
 * ...
 * LP_INT_ENABLE[31:0] ...
 * LP_INT_ENABLE[63:31] ...
 * LP_INT_ENABLE[94:64] ...
 * LP0_CONFIG1 (gpio 0) config1 reg for gpio 0 (per gpio registers)
 * LP0_CONFIG2 (gpio 0) config2 reg for gpio 0
 * LP1_CONFIG1 (gpio 1) config1 reg for gpio 1
 * LP1_CONFIG2 (gpio 1) config2 reg for gpio 1
 * LP2_CONFIG1 (gpio 2) ...
 * LP2_CONFIG2 (gpio 2) ...
 * ...
 * LP94_CONFIG1 (gpio 94) ...
 * LP94_CONFIG2 (gpio 94) ...
 */

static unsigned long lp_gpio_reg(struct gpio_chip *chip, unsigned offset,
                                 int reg)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        int reg_offset;

        if (reg == LP_CONFIG1 || reg == LP_CONFIG2)
                /* per gpio specific config registers */
                reg_offset = offset * 8;
        else
                /* bitmapped registers */
                reg_offset = (offset / 32) * 4;

        return lg->reg_base + reg + reg_offset;
}

static int lp_gpio_request(struct gpio_chip *chip, unsigned offset)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
        unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);
        unsigned long acpi_use = lp_gpio_reg(chip, offset, LP_ACPI_OWNED);

        pm_runtime_get(&lg->pdev->dev); /* should we put if failed */

        /* Fail if BIOS reserved pin for ACPI use */
        if (!(inl(acpi_use) & BIT(offset % 32))) {
                dev_err(&lg->pdev->dev, "gpio %d reserved for ACPI\n", offset);
                return -EBUSY;
        }
        /* Fail if pin is in alternate function mode (not GPIO mode) */
        if (!(inl(reg) & USE_SEL_BIT))
                return -ENODEV;

        /* enable input sensing */
        outl(inl(conf2) & ~GPINDIS_BIT, conf2);


        return 0;
}

static void lp_gpio_free(struct gpio_chip *chip, unsigned offset)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        unsigned long conf2 = lp_gpio_reg(chip, offset, LP_CONFIG2);

        /* disable input sensing */
        outl(inl(conf2) | GPINDIS_BIT, conf2);

        pm_runtime_put(&lg->pdev->dev);
}

static int lp_irq_type(struct irq_data *d, unsigned type)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct lp_gpio *lg = gpiochip_get_data(gc);
        u32 hwirq = irqd_to_hwirq(d);
        unsigned long flags;
        u32 value;
        unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_CONFIG1);

        if (hwirq >= lg->chip.ngpio)
                return -EINVAL;

        spin_lock_irqsave(&lg->lock, flags);
        value = inl(reg);

        /* set both TRIG_SEL and INV bits to 0 for rising edge */
        if (type & IRQ_TYPE_EDGE_RISING)
                value &= ~(TRIG_SEL_BIT | INT_INV_BIT);

        /* TRIG_SEL bit 0, INV bit 1 for falling edge */
        if (type & IRQ_TYPE_EDGE_FALLING)
                value = (value | INT_INV_BIT) & ~TRIG_SEL_BIT;

        /* TRIG_SEL bit 1, INV bit 0 for level low */
        if (type & IRQ_TYPE_LEVEL_LOW)
                value = (value | TRIG_SEL_BIT) & ~INT_INV_BIT;

        /* TRIG_SEL bit 1, INV bit 1 for level high */
        if (type & IRQ_TYPE_LEVEL_HIGH)
                value |= TRIG_SEL_BIT | INT_INV_BIT;

        outl(value, reg);
        spin_unlock_irqrestore(&lg->lock, flags);

        return 0;
}

static int lp_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
        return !!(inl(reg) & IN_LVL_BIT);
}

static void lp_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
        unsigned long flags;

        spin_lock_irqsave(&lg->lock, flags);

        if (value)
                outl(inl(reg) | OUT_LVL_BIT, reg);
        else
                outl(inl(reg) & ~OUT_LVL_BIT, reg);

        spin_unlock_irqrestore(&lg->lock, flags);
}

static int lp_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
        unsigned long flags;

        spin_lock_irqsave(&lg->lock, flags);
        outl(inl(reg) | DIR_BIT, reg);
        spin_unlock_irqrestore(&lg->lock, flags);

        return 0;
}

static int lp_gpio_direction_output(struct gpio_chip *chip,
                                      unsigned offset, int value)
{
        struct lp_gpio *lg = gpiochip_get_data(chip);
        unsigned long reg = lp_gpio_reg(chip, offset, LP_CONFIG1);
        unsigned long flags;

        lp_gpio_set(chip, offset, value);

        spin_lock_irqsave(&lg->lock, flags);
        outl(inl(reg) & ~DIR_BIT, reg);
        spin_unlock_irqrestore(&lg->lock, flags);

        return 0;
}

static void lp_gpio_irq_handler(struct irq_desc *desc)
{
        struct irq_data *data = irq_desc_get_irq_data(desc);
        struct gpio_chip *gc = irq_desc_get_handler_data(desc);
        struct lp_gpio *lg = gpiochip_get_data(gc);
        struct irq_chip *chip = irq_data_get_irq_chip(data);
        u32 base, pin, mask;
        unsigned long reg, ena, pending;

        /* check from GPIO controller which pin triggered the interrupt */
        for (base = 0; base < lg->chip.ngpio; base += 32) {
                reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
                ena = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);

                while ((pending = (inl(reg) & inl(ena)))) {
                        unsigned irq;

                        pin = __ffs(pending);
                        mask = BIT(pin);
                        /* Clear before handling so we don't lose an edge */
                        outl(mask, reg);
                        irq = irq_find_mapping(lg->chip.irqdomain, base + pin);
                        generic_handle_irq(irq);
                }
        }
        chip->irq_eoi(data);
}

static void lp_irq_unmask(struct irq_data *d)
{
}

static void lp_irq_mask(struct irq_data *d)
{
}

static void lp_irq_enable(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct lp_gpio *lg = gpiochip_get_data(gc);
        u32 hwirq = irqd_to_hwirq(d);
        unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
        unsigned long flags;

        spin_lock_irqsave(&lg->lock, flags);
        outl(inl(reg) | BIT(hwirq % 32), reg);
        spin_unlock_irqrestore(&lg->lock, flags);
}

static void lp_irq_disable(struct irq_data *d)
{
        struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
        struct lp_gpio *lg = gpiochip_get_data(gc);
        u32 hwirq = irqd_to_hwirq(d);
        unsigned long reg = lp_gpio_reg(&lg->chip, hwirq, LP_INT_ENABLE);
        unsigned long flags;

        spin_lock_irqsave(&lg->lock, flags);
        outl(inl(reg) & ~BIT(hwirq % 32), reg);
        spin_unlock_irqrestore(&lg->lock, flags);
}

static struct irq_chip lp_irqchip = {
        .name = "LP-GPIO",
        .irq_mask = lp_irq_mask,
        .irq_unmask = lp_irq_unmask,
        .irq_enable = lp_irq_enable,
        .irq_disable = lp_irq_disable,
        .irq_set_type = lp_irq_type,
        .flags = IRQCHIP_SKIP_SET_WAKE,
};

static void lp_gpio_irq_init_hw(struct lp_gpio *lg)
{
        unsigned long reg;
        unsigned base;

        for (base = 0; base < lg->chip.ngpio; base += 32) {
                /* disable gpio pin interrupts */
                reg = lp_gpio_reg(&lg->chip, base, LP_INT_ENABLE);
                outl(0, reg);
                /* Clear interrupt status register */
                reg = lp_gpio_reg(&lg->chip, base, LP_INT_STAT);
                outl(0xffffffff, reg);
        }
}

static int lp_gpio_probe(struct platform_device *pdev)
{
        struct lp_gpio *lg;
        struct gpio_chip *gc;
        struct resource *io_rc, *irq_rc;
        struct device *dev = &pdev->dev;
        unsigned long reg_len;
        int ret = -ENODEV;

        lg = devm_kzalloc(dev, sizeof(struct lp_gpio), GFP_KERNEL);
        if (!lg)
                return -ENOMEM;

        lg->pdev = pdev;
        platform_set_drvdata(pdev, lg);

        io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
        irq_rc = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

        if (!io_rc) {
                dev_err(dev, "missing IO resources\n");
                return -EINVAL;
        }

        lg->reg_base = io_rc->start;
        reg_len = resource_size(io_rc);

        if (!devm_request_region(dev, lg->reg_base, reg_len, "lp-gpio")) {
                dev_err(dev, "failed requesting IO region 0x%x\n",
                        (unsigned int)lg->reg_base);
                return -EBUSY;
        }

        spin_lock_init(&lg->lock);

        gc = &lg->chip;
        gc->label = dev_name(dev);
        gc->owner = THIS_MODULE;
        gc->request = lp_gpio_request;
        gc->free = lp_gpio_free;
        gc->direction_input = lp_gpio_direction_input;
        gc->direction_output = lp_gpio_direction_output;
        gc->get = lp_gpio_get;
        gc->set = lp_gpio_set;
        gc->base = -1;
        gc->ngpio = LP_NUM_GPIO;
        gc->can_sleep = false;
        gc->parent = dev;

        ret = devm_gpiochip_add_data(dev, gc, lg);
        if (ret) {
                dev_err(dev, "failed adding lp-gpio chip\n");
                return ret;
        }

        /* set up interrupts  */
        if (irq_rc && irq_rc->start) {
                lp_gpio_irq_init_hw(lg);
                ret = gpiochip_irqchip_add(gc, &lp_irqchip, 0,
                                           handle_simple_irq, IRQ_TYPE_NONE);
                if (ret) {
                        dev_err(dev, "failed to add irqchip\n");
                        return ret;
                }

                gpiochip_set_chained_irqchip(gc, &lp_irqchip,
                                             (unsigned)irq_rc->start,
                                             lp_gpio_irq_handler);
        }

        pm_runtime_enable(dev);

        return 0;
}

static int lp_gpio_runtime_suspend(struct device *dev)
{
        return 0;
}

static int lp_gpio_runtime_resume(struct device *dev)
{
        return 0;
}

static int lp_gpio_resume(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct lp_gpio *lg = platform_get_drvdata(pdev);
        unsigned long reg;
        int i;

        /* on some hardware suspend clears input sensing, re-enable it here */
        for (i = 0; i < lg->chip.ngpio; i++) {
                if (gpiochip_is_requested(&lg->chip, i) != NULL) {
                        reg = lp_gpio_reg(&lg->chip, i, LP_CONFIG2);
                        outl(inl(reg) & ~GPINDIS_BIT, reg);
                }
        }
        return 0;
}

static const struct dev_pm_ops lp_gpio_pm_ops = {
        .runtime_suspend = lp_gpio_runtime_suspend,
        .runtime_resume = lp_gpio_runtime_resume,
        .resume = lp_gpio_resume,
};

static const struct acpi_device_id lynxpoint_gpio_acpi_match[] = {
        { "INT33C7", 0 },
        { "INT3437", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, lynxpoint_gpio_acpi_match);

static int lp_gpio_remove(struct platform_device *pdev)
{
        pm_runtime_disable(&pdev->dev);
        return 0;
}

static struct platform_driver lp_gpio_driver = {
        .probe          = lp_gpio_probe,
        .remove         = lp_gpio_remove,
        .driver         = {
                .name   = "lp_gpio",
                .pm     = &lp_gpio_pm_ops,
                .acpi_match_table = ACPI_PTR(lynxpoint_gpio_acpi_match),
        },
};

static int __init lp_gpio_init(void)
{
        return platform_driver_register(&lp_gpio_driver);
}

static void __exit lp_gpio_exit(void)
{
        platform_driver_unregister(&lp_gpio_driver);
}

subsys_initcall(lp_gpio_init);
module_exit(lp_gpio_exit);

MODULE_AUTHOR("Mathias Nyman (Intel)");
MODULE_DESCRIPTION("GPIO interface for Intel Lynxpoint");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lp_gpio");