Revision dc280d93623927570da279e99393879dbbab39e7 authored by Thomas Gleixner on 21 December 2016, 19:19:49 UTC, committed by Thomas Gleixner on 25 December 2016, 09:47:42 UTC
Developers manage to overwrite states blindly without thought. That's fatal
and hard to debug. Add sanity checks to make it fail.

This requries to restructure the code so that the dynamic state allocation
happens in the same lock protected section as the actual store. Otherwise
the previous assignment of 'Reserved' to the name field would trigger the
overwrite check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Link: http://lkml.kernel.org/r/20161221192111.675234535@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 parent 59fefd0
Raw File
wm8350-core.c
/*
 * wm8350-core.c  --  Device access for Wolfson WM8350
 *
 * Copyright 2007, 2008 Wolfson Microelectronics PLC.
 *
 * Author: Liam Girdwood, Mark Brown
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/bug.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/regmap.h>
#include <linux/workqueue.h>

#include <linux/mfd/wm8350/core.h>
#include <linux/mfd/wm8350/audio.h>
#include <linux/mfd/wm8350/comparator.h>
#include <linux/mfd/wm8350/gpio.h>
#include <linux/mfd/wm8350/pmic.h>
#include <linux/mfd/wm8350/rtc.h>
#include <linux/mfd/wm8350/supply.h>
#include <linux/mfd/wm8350/wdt.h>

#define WM8350_CLOCK_CONTROL_1		0x28
#define WM8350_AIF_TEST			0x74

/* debug */
#define WM8350_BUS_DEBUG 0
#if WM8350_BUS_DEBUG
#define dump(regs, src) do { \
	int i_; \
	u16 *src_ = src; \
	printk(KERN_DEBUG); \
	for (i_ = 0; i_ < regs; i_++) \
		printk(" 0x%4.4x", *src_++); \
	printk("\n"); \
} while (0);
#else
#define dump(bytes, src)
#endif

#define WM8350_LOCK_DEBUG 0
#if WM8350_LOCK_DEBUG
#define ldbg(format, arg...) printk(format, ## arg)
#else
#define ldbg(format, arg...)
#endif

/*
 * WM8350 Device IO
 */
static DEFINE_MUTEX(reg_lock_mutex);

/*
 * Safe read, modify, write methods
 */
int wm8350_clear_bits(struct wm8350 *wm8350, u16 reg, u16 mask)
{
	return regmap_update_bits(wm8350->regmap, reg, mask, 0);
}
EXPORT_SYMBOL_GPL(wm8350_clear_bits);

int wm8350_set_bits(struct wm8350 *wm8350, u16 reg, u16 mask)
{
	return regmap_update_bits(wm8350->regmap, reg, mask, mask);
}
EXPORT_SYMBOL_GPL(wm8350_set_bits);

u16 wm8350_reg_read(struct wm8350 *wm8350, int reg)
{
	unsigned int data;
	int err;

	err = regmap_read(wm8350->regmap, reg, &data);
	if (err)
		dev_err(wm8350->dev, "read from reg R%d failed\n", reg);

	return data;
}
EXPORT_SYMBOL_GPL(wm8350_reg_read);

int wm8350_reg_write(struct wm8350 *wm8350, int reg, u16 val)
{
	int ret;

	ret = regmap_write(wm8350->regmap, reg, val);

	if (ret)
		dev_err(wm8350->dev, "write to reg R%d failed\n", reg);
	return ret;
}
EXPORT_SYMBOL_GPL(wm8350_reg_write);

int wm8350_block_read(struct wm8350 *wm8350, int start_reg, int regs,
		      u16 *dest)
{
	int err = 0;

	err = regmap_bulk_read(wm8350->regmap, start_reg, dest, regs);
	if (err)
		dev_err(wm8350->dev, "block read starting from R%d failed\n",
			start_reg);

	return err;
}
EXPORT_SYMBOL_GPL(wm8350_block_read);

int wm8350_block_write(struct wm8350 *wm8350, int start_reg, int regs,
		       u16 *src)
{
	int ret = 0;

	ret = regmap_bulk_write(wm8350->regmap, start_reg, src, regs);
	if (ret)
		dev_err(wm8350->dev, "block write starting at R%d failed\n",
			start_reg);

	return ret;
}
EXPORT_SYMBOL_GPL(wm8350_block_write);

/**
 * wm8350_reg_lock()
 *
 * The WM8350 has a hardware lock which can be used to prevent writes to
 * some registers (generally those which can cause particularly serious
 * problems if misused).  This function enables that lock.
 */
int wm8350_reg_lock(struct wm8350 *wm8350)
{
	int ret;

	mutex_lock(&reg_lock_mutex);

	ldbg(__func__);

	ret = wm8350_reg_write(wm8350, WM8350_SECURITY, WM8350_LOCK_KEY);
	if (ret)
		dev_err(wm8350->dev, "lock failed\n");

	wm8350->unlocked = false;

	mutex_unlock(&reg_lock_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(wm8350_reg_lock);

/**
 * wm8350_reg_unlock()
 *
 * The WM8350 has a hardware lock which can be used to prevent writes to
 * some registers (generally those which can cause particularly serious
 * problems if misused).  This function disables that lock so updates
 * can be performed.  For maximum safety this should be done only when
 * required.
 */
int wm8350_reg_unlock(struct wm8350 *wm8350)
{
	int ret;

	mutex_lock(&reg_lock_mutex);

	ldbg(__func__);

	ret = wm8350_reg_write(wm8350, WM8350_SECURITY, WM8350_UNLOCK_KEY);
	if (ret)
		dev_err(wm8350->dev, "unlock failed\n");

	wm8350->unlocked = true;

	mutex_unlock(&reg_lock_mutex);

	return ret;
}
EXPORT_SYMBOL_GPL(wm8350_reg_unlock);

int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale, int vref)
{
	u16 reg, result = 0;

	if (channel < WM8350_AUXADC_AUX1 || channel > WM8350_AUXADC_TEMP)
		return -EINVAL;
	if (channel >= WM8350_AUXADC_USB && channel <= WM8350_AUXADC_TEMP
	    && (scale != 0 || vref != 0))
		return -EINVAL;

	mutex_lock(&wm8350->auxadc_mutex);

	/* Turn on the ADC */
	reg = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
	wm8350_reg_write(wm8350, WM8350_POWER_MGMT_5, reg | WM8350_AUXADC_ENA);

	if (scale || vref) {
		reg = scale << 13;
		reg |= vref << 12;
		wm8350_reg_write(wm8350, WM8350_AUX1_READBACK + channel, reg);
	}

	reg = wm8350_reg_read(wm8350, WM8350_DIGITISER_CONTROL_1);
	reg |= 1 << channel | WM8350_AUXADC_POLL;
	wm8350_reg_write(wm8350, WM8350_DIGITISER_CONTROL_1, reg);

	/* If a late IRQ left the completion signalled then consume
	 * the completion. */
	try_wait_for_completion(&wm8350->auxadc_done);

	/* We ignore the result of the completion and just check for a
	 * conversion result, allowing us to soldier on if the IRQ
	 * infrastructure is not set up for the chip. */
	wait_for_completion_timeout(&wm8350->auxadc_done, msecs_to_jiffies(5));

	reg = wm8350_reg_read(wm8350, WM8350_DIGITISER_CONTROL_1);
	if (reg & WM8350_AUXADC_POLL)
		dev_err(wm8350->dev, "adc chn %d read timeout\n", channel);
	else
		result = wm8350_reg_read(wm8350,
					 WM8350_AUX1_READBACK + channel);

	/* Turn off the ADC */
	reg = wm8350_reg_read(wm8350, WM8350_POWER_MGMT_5);
	wm8350_reg_write(wm8350, WM8350_POWER_MGMT_5,
			 reg & ~WM8350_AUXADC_ENA);

	mutex_unlock(&wm8350->auxadc_mutex);

	return result & WM8350_AUXADC_DATA1_MASK;
}
EXPORT_SYMBOL_GPL(wm8350_read_auxadc);

static irqreturn_t wm8350_auxadc_irq(int irq, void *irq_data)
{
	struct wm8350 *wm8350 = irq_data;

	complete(&wm8350->auxadc_done);

	return IRQ_HANDLED;
}

/*
 * Register a client device.  This is non-fatal since there is no need to
 * fail the entire device init due to a single platform device failing.
 */
static void wm8350_client_dev_register(struct wm8350 *wm8350,
				       const char *name,
				       struct platform_device **pdev)
{
	int ret;

	*pdev = platform_device_alloc(name, -1);
	if (*pdev == NULL) {
		dev_err(wm8350->dev, "Failed to allocate %s\n", name);
		return;
	}

	(*pdev)->dev.parent = wm8350->dev;
	platform_set_drvdata(*pdev, wm8350);
	ret = platform_device_add(*pdev);
	if (ret != 0) {
		dev_err(wm8350->dev, "Failed to register %s: %d\n", name, ret);
		platform_device_put(*pdev);
		*pdev = NULL;
	}
}

int wm8350_device_init(struct wm8350 *wm8350, int irq,
		       struct wm8350_platform_data *pdata)
{
	int ret;
	unsigned int id1, id2, mask_rev;
	unsigned int cust_id, mode, chip_rev;

	dev_set_drvdata(wm8350->dev, wm8350);

	/* get WM8350 revision and config mode */
	ret = regmap_read(wm8350->regmap, WM8350_RESET_ID, &id1);
	if (ret != 0) {
		dev_err(wm8350->dev, "Failed to read ID: %d\n", ret);
		goto err;
	}

	ret = regmap_read(wm8350->regmap, WM8350_ID, &id2);
	if (ret != 0) {
		dev_err(wm8350->dev, "Failed to read ID: %d\n", ret);
		goto err;
	}

	ret = regmap_read(wm8350->regmap, WM8350_REVISION, &mask_rev);
	if (ret != 0) {
		dev_err(wm8350->dev, "Failed to read revision: %d\n", ret);
		goto err;
	}

	if (id1 != 0x6143) {
		dev_err(wm8350->dev,
			"Device with ID %x is not a WM8350\n", id1);
		ret = -ENODEV;
		goto err;
	}

	mode = (id2 & WM8350_CONF_STS_MASK) >> 10;
	cust_id = id2 & WM8350_CUST_ID_MASK;
	chip_rev = (id2 & WM8350_CHIP_REV_MASK) >> 12;
	dev_info(wm8350->dev,
		 "CONF_STS %d, CUST_ID %d, MASK_REV %d, CHIP_REV %d\n",
		 mode, cust_id, mask_rev, chip_rev);

	if (cust_id != 0) {
		dev_err(wm8350->dev, "Unsupported CUST_ID\n");
		ret = -ENODEV;
		goto err;
	}

	switch (mask_rev) {
	case 0:
		wm8350->pmic.max_dcdc = WM8350_DCDC_6;
		wm8350->pmic.max_isink = WM8350_ISINK_B;

		switch (chip_rev) {
		case WM8350_REV_E:
			dev_info(wm8350->dev, "WM8350 Rev E\n");
			break;
		case WM8350_REV_F:
			dev_info(wm8350->dev, "WM8350 Rev F\n");
			break;
		case WM8350_REV_G:
			dev_info(wm8350->dev, "WM8350 Rev G\n");
			wm8350->power.rev_g_coeff = 1;
			break;
		case WM8350_REV_H:
			dev_info(wm8350->dev, "WM8350 Rev H\n");
			wm8350->power.rev_g_coeff = 1;
			break;
		default:
			/* For safety we refuse to run on unknown hardware */
			dev_err(wm8350->dev, "Unknown WM8350 CHIP_REV\n");
			ret = -ENODEV;
			goto err;
		}
		break;

	case 1:
		wm8350->pmic.max_dcdc = WM8350_DCDC_4;
		wm8350->pmic.max_isink = WM8350_ISINK_A;

		switch (chip_rev) {
		case 0:
			dev_info(wm8350->dev, "WM8351 Rev A\n");
			wm8350->power.rev_g_coeff = 1;
			break;

		case 1:
			dev_info(wm8350->dev, "WM8351 Rev B\n");
			wm8350->power.rev_g_coeff = 1;
			break;

		default:
			dev_err(wm8350->dev, "Unknown WM8351 CHIP_REV\n");
			ret = -ENODEV;
			goto err;
		}
		break;

	case 2:
		wm8350->pmic.max_dcdc = WM8350_DCDC_6;
		wm8350->pmic.max_isink = WM8350_ISINK_B;

		switch (chip_rev) {
		case 0:
			dev_info(wm8350->dev, "WM8352 Rev A\n");
			wm8350->power.rev_g_coeff = 1;
			break;

		default:
			dev_err(wm8350->dev, "Unknown WM8352 CHIP_REV\n");
			ret = -ENODEV;
			goto err;
		}
		break;

	default:
		dev_err(wm8350->dev, "Unknown MASK_REV\n");
		ret = -ENODEV;
		goto err;
	}

	mutex_init(&wm8350->auxadc_mutex);
	init_completion(&wm8350->auxadc_done);

	ret = wm8350_irq_init(wm8350, irq, pdata);
	if (ret < 0)
		goto err;

	if (wm8350->irq_base) {
		ret = request_threaded_irq(wm8350->irq_base +
					   WM8350_IRQ_AUXADC_DATARDY,
					   NULL, wm8350_auxadc_irq,
					   IRQF_ONESHOT,
					   "auxadc", wm8350);
		if (ret < 0)
			dev_warn(wm8350->dev,
				 "Failed to request AUXADC IRQ: %d\n", ret);
	}

	if (pdata && pdata->init) {
		ret = pdata->init(wm8350);
		if (ret != 0) {
			dev_err(wm8350->dev, "Platform init() failed: %d\n",
				ret);
			goto err_irq;
		}
	}

	wm8350_reg_write(wm8350, WM8350_SYSTEM_INTERRUPTS_MASK, 0x0);

	wm8350_client_dev_register(wm8350, "wm8350-codec",
				   &(wm8350->codec.pdev));
	wm8350_client_dev_register(wm8350, "wm8350-gpio",
				   &(wm8350->gpio.pdev));
	wm8350_client_dev_register(wm8350, "wm8350-hwmon",
				   &(wm8350->hwmon.pdev));
	wm8350_client_dev_register(wm8350, "wm8350-power",
				   &(wm8350->power.pdev));
	wm8350_client_dev_register(wm8350, "wm8350-rtc", &(wm8350->rtc.pdev));
	wm8350_client_dev_register(wm8350, "wm8350-wdt", &(wm8350->wdt.pdev));

	return 0;

err_irq:
	wm8350_irq_exit(wm8350);
err:
	return ret;
}
EXPORT_SYMBOL_GPL(wm8350_device_init);

void wm8350_device_exit(struct wm8350 *wm8350)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(wm8350->pmic.led); i++)
		platform_device_unregister(wm8350->pmic.led[i].pdev);

	for (i = 0; i < ARRAY_SIZE(wm8350->pmic.pdev); i++)
		platform_device_unregister(wm8350->pmic.pdev[i]);

	platform_device_unregister(wm8350->wdt.pdev);
	platform_device_unregister(wm8350->rtc.pdev);
	platform_device_unregister(wm8350->power.pdev);
	platform_device_unregister(wm8350->hwmon.pdev);
	platform_device_unregister(wm8350->gpio.pdev);
	platform_device_unregister(wm8350->codec.pdev);

	if (wm8350->irq_base)
		free_irq(wm8350->irq_base + WM8350_IRQ_AUXADC_DATARDY, wm8350);

	wm8350_irq_exit(wm8350);
}
EXPORT_SYMBOL_GPL(wm8350_device_exit);

MODULE_DESCRIPTION("WM8350 AudioPlus PMIC core driver");
MODULE_LICENSE("GPL");
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