/*
 * Helpers for controlling modem lines via GPIO
 *
 * Copyright (C) 2014 Paratronic S.A.
 *
 * 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 <linux/err.h>
#include <linux/device.h>
#include <linux/irq.h>
#include <linux/gpio/consumer.h>
#include <linux/termios.h>
#include <linux/serial_core.h>
#include <linux/module.h>

#include "serial_mctrl_gpio.h"

struct mctrl_gpios {
	struct uart_port *port;
	struct gpio_desc *gpio[UART_GPIO_MAX];
	int irq[UART_GPIO_MAX];
	unsigned int mctrl_prev;
	bool mctrl_on;
};

static const struct {
	const char *name;
	unsigned int mctrl;
	bool dir_out;
} mctrl_gpios_desc[UART_GPIO_MAX] = {
	{ "cts", TIOCM_CTS, false, },
	{ "dsr", TIOCM_DSR, false, },
	{ "dcd", TIOCM_CD, false, },
	{ "rng", TIOCM_RNG, false, },
	{ "rts", TIOCM_RTS, true, },
	{ "dtr", TIOCM_DTR, true, },
};

void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
{
	enum mctrl_gpio_idx i;
	struct gpio_desc *desc_array[UART_GPIO_MAX];
	int value_array[UART_GPIO_MAX];
	unsigned int count = 0;

	if (gpios == NULL)
		return;

	for (i = 0; i < UART_GPIO_MAX; i++)
		if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
			desc_array[count] = gpios->gpio[i];
			value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
			count++;
		}
	gpiod_set_array_value(count, desc_array, value_array);
}
EXPORT_SYMBOL_GPL(mctrl_gpio_set);

struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
				      enum mctrl_gpio_idx gidx)
{
	return gpios->gpio[gidx];
}
EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);

unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return *mctrl;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
			if (gpiod_get_value(gpios->gpio[i]))
				*mctrl |= mctrl_gpios_desc[i].mctrl;
			else
				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
		}
	}

	return *mctrl;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_get);

unsigned int
mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return *mctrl;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
			if (gpiod_get_value(gpios->gpio[i]))
				*mctrl |= mctrl_gpios_desc[i].mctrl;
			else
				*mctrl &= ~mctrl_gpios_desc[i].mctrl;
		}
	}

	return *mctrl;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);

struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
{
	struct mctrl_gpios *gpios;
	enum mctrl_gpio_idx i;

	gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
	if (!gpios)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < UART_GPIO_MAX; i++) {
		enum gpiod_flags flags;

		if (mctrl_gpios_desc[i].dir_out)
			flags = GPIOD_OUT_LOW;
		else
			flags = GPIOD_IN;

		gpios->gpio[i] =
			devm_gpiod_get_index_optional(dev,
						      mctrl_gpios_desc[i].name,
						      idx, flags);

		if (IS_ERR(gpios->gpio[i]))
			return ERR_CAST(gpios->gpio[i]);
	}

	return gpios;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);

#define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
{
	struct mctrl_gpios *gpios = context;
	struct uart_port *port = gpios->port;
	u32 mctrl = gpios->mctrl_prev;
	u32 mctrl_diff;
	unsigned long flags;

	mctrl_gpio_get(gpios, &mctrl);

	spin_lock_irqsave(&port->lock, flags);

	mctrl_diff = mctrl ^ gpios->mctrl_prev;
	gpios->mctrl_prev = mctrl;

	if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
		if ((mctrl_diff & mctrl) & TIOCM_RI)
			port->icount.rng++;

		if ((mctrl_diff & mctrl) & TIOCM_DSR)
			port->icount.dsr++;

		if (mctrl_diff & TIOCM_CD)
			uart_handle_dcd_change(port, mctrl & TIOCM_CD);

		if (mctrl_diff & TIOCM_CTS)
			uart_handle_cts_change(port, mctrl & TIOCM_CTS);

		wake_up_interruptible(&port->state->port.delta_msr_wait);
	}

	spin_unlock_irqrestore(&port->lock, flags);

	return IRQ_HANDLED;
}

struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
{
	struct mctrl_gpios *gpios;
	enum mctrl_gpio_idx i;

	gpios = mctrl_gpio_init_noauto(port->dev, idx);
	if (IS_ERR(gpios))
		return gpios;

	gpios->port = port;

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		int ret;

		if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
			continue;

		ret = gpiod_to_irq(gpios->gpio[i]);
		if (ret <= 0) {
			dev_err(port->dev,
				"failed to find corresponding irq for %s (idx=%d, err=%d)\n",
				mctrl_gpios_desc[i].name, idx, ret);
			return ERR_PTR(ret);
		}
		gpios->irq[i] = ret;

		/* irqs should only be enabled in .enable_ms */
		irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);

		ret = devm_request_irq(port->dev, gpios->irq[i],
				       mctrl_gpio_irq_handle,
				       IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
				       gpios);
		if (ret) {
			/* alternatively implement polling */
			dev_err(port->dev,
				"failed to request irq for %s (idx=%d, err=%d)\n",
				mctrl_gpios_desc[i].name, idx, ret);
			return ERR_PTR(ret);
		}
	}

	return gpios;
}
EXPORT_SYMBOL_GPL(mctrl_gpio_init);

void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	for (i = 0; i < UART_GPIO_MAX; i++) {
		if (gpios->irq[i])
			devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);

		if (gpios->gpio[i])
			devm_gpiod_put(dev, gpios->gpio[i]);
	}
	devm_kfree(dev, gpios);
}
EXPORT_SYMBOL_GPL(mctrl_gpio_free);

void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	/* .enable_ms may be called multiple times */
	if (gpios->mctrl_on)
		return;

	gpios->mctrl_on = true;

	/* get initial status of modem lines GPIOs */
	mctrl_gpio_get(gpios, &gpios->mctrl_prev);

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		if (!gpios->irq[i])
			continue;

		enable_irq(gpios->irq[i]);
	}
}
EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);

void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
{
	enum mctrl_gpio_idx i;

	if (gpios == NULL)
		return;

	if (!gpios->mctrl_on)
		return;

	gpios->mctrl_on = false;

	for (i = 0; i < UART_GPIO_MAX; ++i) {
		if (!gpios->irq[i])
			continue;

		disable_irq(gpios->irq[i]);
	}
}
EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);

MODULE_LICENSE("GPL");
ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola &lt;erik.veijola@intel.com&gt;
Tested-by: Borislav Petkov &lt;bp@alien8.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>Diffstat</a> (limited to 'sound/soc/omap/am3517evm.c')</div><table summary='diffstat' class='diffstat'>