/*
 * drivers/w1/slaves/w1_bq27000.c
 *
 * Copyright (C) 2007 Texas Instruments, Inc.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/power/bq27xxx_battery.h>

#include "../w1.h"
#include "../w1_int.h"
#include "../w1_family.h"

#define HDQ_CMD_READ	(0)
#define HDQ_CMD_WRITE	(1<<7)

static int F_ID;

static int w1_bq27000_read(struct device *dev, unsigned int reg)
{
	u8 val;
	struct w1_slave *sl = container_of(dev->parent, struct w1_slave, dev);

	mutex_lock(&sl->master->bus_mutex);
	w1_write_8(sl->master, HDQ_CMD_READ | reg);
	val = w1_read_8(sl->master);
	mutex_unlock(&sl->master->bus_mutex);

	return val;
}

static struct bq27xxx_platform_data bq27000_battery_info = {
	.read   = w1_bq27000_read,
	.name   = "bq27000-battery",
	.chip   = BQ27000,
};

static int w1_bq27000_add_slave(struct w1_slave *sl)
{
	int ret;
	struct platform_device *pdev;

	pdev = platform_device_alloc("bq27000-battery", -1);
	if (!pdev) {
		ret = -ENOMEM;
		return ret;
	}
	ret = platform_device_add_data(pdev,
				       &bq27000_battery_info,
				       sizeof(bq27000_battery_info));
	if (ret)
		goto pdev_add_failed;
	pdev->dev.parent = &sl->dev;

	ret = platform_device_add(pdev);
	if (ret)
		goto pdev_add_failed;

	dev_set_drvdata(&sl->dev, pdev);

	goto success;

pdev_add_failed:
	platform_device_put(pdev);
success:
	return ret;
}

static void w1_bq27000_remove_slave(struct w1_slave *sl)
{
	struct platform_device *pdev = dev_get_drvdata(&sl->dev);

	platform_device_unregister(pdev);
}

static struct w1_family_ops w1_bq27000_fops = {
	.add_slave	= w1_bq27000_add_slave,
	.remove_slave	= w1_bq27000_remove_slave,
};

static struct w1_family w1_bq27000_family = {
	.fid = W1_FAMILY_BQ27000,
	.fops = &w1_bq27000_fops,
};

static int __init w1_bq27000_init(void)
{
	if (F_ID)
		w1_bq27000_family.fid = F_ID;

	return w1_register_family(&w1_bq27000_family);
}

static void __exit w1_bq27000_exit(void)
{
	w1_unregister_family(&w1_bq27000_family);
}


module_init(w1_bq27000_init);
module_exit(w1_bq27000_exit);

module_param(F_ID, int, S_IRUSR);
MODULE_PARM_DESC(F_ID, "1-wire slave FID for BQ device");
MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_BQ27000));
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Texas Instruments Ltd");
MODULE_DESCRIPTION("HDQ/1-wire slave driver bq27000 battery monitor chip");
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>perf</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>pmu-events</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>arch</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch/x86?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>x86</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch/x86/bonnell?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>bonnell</a>/<a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>cache.json</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='c8f325a59cfc718d13a50fbc746ed9b415c25e92'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;</td><td class='right'>2017-02-01 17:45:02 +0000</td></tr>
<tr><th>committer</th><td>Ingo Molnar &lt;mingo@kernel.org&gt;</td><td class='right'>2017-02-01 21:17:49 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>c8f325a59cfc718d13a50fbc746ed9b415c25e92</a> (<a href='/cgit.cgi/linux/net-next.git/patch/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>d53fbdac9d0781e39a13b2ac6b2bd258cf3b4140</a> /<a href='/cgit.cgi/linux/net-next.git/tree/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>tools/perf/pmu-events/arch/x86/bonnell/cache.json</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=bf29bddf0417a4783da3b24e8c9e017ac649326f'>bf29bddf0417a4783da3b24e8c9e017ac649326f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/tools/perf/pmu-events/arch/x86/bonnell/cache.json?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92&amp;id2=bf29bddf0417a4783da3b24e8c9e017ac649326f'>diff</a>)</td></tr></table>
<div class='commit-subject'>efi/fdt: Avoid FDT manipulation after ExitBootServices()</div><div class='commit-msg'>Some AArch64 UEFI implementations disable the MMU in ExitBootServices(),
after which unaligned accesses to RAM are no longer supported.

Commit:

  abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")

fixed an issue in the memory map handling of the stub FDT code, but
inadvertently created an issue with such firmware, by moving some
of the FDT manipulation to after the invocation of ExitBootServices().

Given that the stub's libfdt implementation uses the ordinary, accelerated
string functions, which rely on hardware handling of unaligned accesses,
manipulating the FDT with the MMU off may result in alignment faults.

So fix the situation by moving the update_fdt_memmap() call into the
callback function invoked by efi_exit_boot_services() right before it
calls the ExitBootServices() UEFI service (which is arguably a better
place for it anyway)

Note that disabling the MMU in ExitBootServices() is not compliant with
the UEFI spec, and carries great risk due to the fact that switching from
cached to uncached memory accesses halfway through compiler generated code
(i.e., involving a stack) can never be done in a way that is architecturally
safe.

Fixes: abfb7b686a3e ("efi/libstub/arm*: Pass latest memory map to the kernel")
Signed-off-by: Ard Biesheuvel &lt;ard.biesheuvel@linaro.org&gt;
Tested-by: Riku Voipio &lt;riku.voipio@linaro.org&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Cc: mark.rutland@arm.com
Cc: linux-efi@vger.kernel.org
Cc: matt@codeblueprint.co.uk
Cc: leif.lindholm@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1485971102-23330-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c8f325a59cfc718d13a50fbc746ed9b415c25e92'>Diffstat</a> (limited to 'tools/perf/pmu-events/arch/x86/bonnell/cache.json')</div><table summary='diffstat' class='diffstat'>