diff mbox series

[V7,5/5] platform/x86: Intel PMT Crashlog capability driver

Message ID 20201001014250.26987-6-david.e.box@linux.intel.com
State New
Headers show
Series Intel Platform Monitoring Technology | expand

Commit Message

David E. Box Oct. 1, 2020, 1:42 a.m. UTC
From: Alexander Duyck <alexander.h.duyck@linux.intel.com>

Add support for the Intel Platform Monitoring Technology crashlog
interface. This interface provides a few sysfs values to allow for
controlling the crashlog telemetry interface as well as a character driver
to allow for mapping the crashlog memory region so that it can be accessed
after a crashlog has been recorded.

This driver is meant to only support the server version of the crashlog
which is identified as crash_type 1 with a version of zero. Currently no
other types are supported.

Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
---
 .../ABI/testing/sysfs-class-intel_pmt         |  65 ++++
 drivers/platform/x86/Kconfig                  |   8 +
 drivers/platform/x86/Makefile                 |   1 +
 drivers/platform/x86/intel_pmt_crashlog.c     | 339 ++++++++++++++++++
 4 files changed, 413 insertions(+)
 create mode 100644 drivers/platform/x86/intel_pmt_crashlog.c

Comments

Andy Shevchenko Oct. 1, 2020, 4:35 p.m. UTC | #1
On Thu, Oct 1, 2020 at 4:43 AM David E. Box <david.e.box@linux.intel.com> wrote:
> Add support for the Intel Platform Monitoring Technology crashlog
> interface. This interface provides a few sysfs values to allow for
> controlling the crashlog telemetry interface as well as a character driver
> to allow for mapping the crashlog memory region so that it can be accessed
> after a crashlog has been recorded.
>
> This driver is meant to only support the server version of the crashlog
> which is identified as crash_type 1 with a version of zero. Currently no
> other types are supported.

...

> +               The crashlog<x> directory contains files for configuring an
> +               instance of a PMT crashlog device that can perform crash data
> +               recoring. Each crashlog<x> device has an associated crashlog

recording

> +               file. This file can be opened and mapped or read to access the
> +               resulting crashlog buffer. The register layout for the buffer
> +               can be determined from an XML file of specified guid for the
> +               parent device.

...

> +               (RO) The guid for this crashlog device. The guid identifies the

guid -> GUID

Please, spell check all ABI files in this series.

...

> +config INTEL_PMT_CRASHLOG
> +       tristate "Intel Platform Monitoring Technology (PMT) Crashlog driver"
> +       select INTEL_PMT_CLASS
> +       help
> +         The Intel Platform Monitoring Technology (PMT) crashlog driver provides
> +         access to hardware crashlog capabilities on devices that support the
> +         feature.

Name of the module?

...

> +       /*

> +        * Currenty we only recognize OOBMSM version 0 devices.

Currently. Please spell check all comments in the code.

> +        * We can ignore all other crashlog devices in the system.
> +        */

...

> +       /* clear control bits */

What new information readers get from this comment?

> +       control &= ~(CRASHLOG_FLAG_MASK | CRASHLOG_FLAG_DISABLE);

How does the second constant play any role here?

...

> +       /* clear control bits */

Ditto. And moreover it's ambiguous due to joined two lines below.

> +       control &= ~CRASHLOG_FLAG_MASK;
> +       control |= CRASHLOG_FLAG_EXECUTE;

...

> +       return strnlen(buf, count);

How is this different to count?

...

> +       struct crashlog_entry *entry;
> +       bool trigger;
> +       int result;
> +

> +       entry = dev_get_drvdata(dev);

You may reduce LOCs by direct assigning in the definition block above.

...

> +       result = strnlen(buf, count);

How is it different from count?

...

> +static DEFINE_XARRAY_ALLOC(crashlog_array);
> +static struct intel_pmt_namespace pmt_crashlog_ns = {
> +       .name = "crashlog",
> +       .xa = &crashlog_array,
> +       .attr_grp = &pmt_crashlog_group

Leave the comma here.

> +};

...

> +       ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, parent);
> +       if (!ret)
> +               return 0;
> +
> +       dev_err(parent, "Failed to add crashlog controls\n");
> +       intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
> +
> +       return ret;

Can we use traditional patterns?
if (ret) {
  ...
}
return ret;

...

> +       size = offsetof(struct pmt_crashlog_priv, entry[pdev->num_resources]);
> +       priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;

struct_size()

...

> +               /* initialize control mutex */
> +               mutex_init(&priv->entry[i].control_mutex);
> +
> +               disc_res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> +               if (!disc_res)
> +                       goto abort_probe;
> +
> +               ret = intel_pmt_ioremap_discovery_table(entry, pdev, i);
> +               if (ret)
> +                       goto abort_probe;
> +
> +               if (!pmt_crashlog_supported(entry))
> +                       continue;
> +
> +               ret = pmt_crashlog_add_entry(entry, &pdev->dev, disc_res);
> +               if (ret)
> +                       goto abort_probe;
> +
> +               priv->num_entries++;

Are you going to duplicate this in each driver? Consider to refactor
to avoid duplication of a lot of code.

...

> +               .name   = DRV_NAME,

> +MODULE_ALIAS("platform:" DRV_NAME);

I'm not sure I have interpreted this:
        - Use 'raw' string instead of defines for device names
correctly. Can you elaborate?

--
With Best Regards,
Andy Shevchenko
Alexander Duyck Oct. 1, 2020, 6:33 p.m. UTC | #2
On Thu, Oct 1, 2020 at 9:37 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Oct 1, 2020 at 4:43 AM David E. Box <david.e.box@linux.intel.com> wrote:
> > Add support for the Intel Platform Monitoring Technology crashlog
> > interface. This interface provides a few sysfs values to allow for
> > controlling the crashlog telemetry interface as well as a character driver
> > to allow for mapping the crashlog memory region so that it can be accessed
> > after a crashlog has been recorded.
> >
> > This driver is meant to only support the server version of the crashlog
> > which is identified as crash_type 1 with a version of zero. Currently no
> > other types are supported.
>
> ...
>
> > +               The crashlog<x> directory contains files for configuring an
> > +               instance of a PMT crashlog device that can perform crash data
> > +               recoring. Each crashlog<x> device has an associated crashlog
>
> recording
>
> > +               file. This file can be opened and mapped or read to access the
> > +               resulting crashlog buffer. The register layout for the buffer
> > +               can be determined from an XML file of specified guid for the
> > +               parent device.
>
> ...
>
> > +               (RO) The guid for this crashlog device. The guid identifies the
>
> guid -> GUID
>
> Please, spell check all ABI files in this series.

I'll run through it again. I am suspecting I must have deleted the "d"
in recording with a fat fingering when I was editing something else.

> ...
>
> > +config INTEL_PMT_CRASHLOG
> > +       tristate "Intel Platform Monitoring Technology (PMT) Crashlog driver"
> > +       select INTEL_PMT_CLASS
> > +       help
> > +         The Intel Platform Monitoring Technology (PMT) crashlog driver provides
> > +         access to hardware crashlog capabilities on devices that support the
> > +         feature.
>
> Name of the module?

I will add the verbiage:
          To compile this driver as a module, choose M here: the module
          will be called intel_pmt_crashlog.


> ...
>
> > +       /*
>
> > +        * Currenty we only recognize OOBMSM version 0 devices.
>
> Currently. Please spell check all comments in the code.

I'll make another pass.

> > +        * We can ignore all other crashlog devices in the system.
> > +        */
>
> ...
>
> > +       /* clear control bits */
>
> What new information readers get from this comment?

Arguably not much. I'll drop the comment.

> > +       control &= ~(CRASHLOG_FLAG_MASK | CRASHLOG_FLAG_DISABLE);
>
> How does the second constant play any role here?

The "control" flags are bits 28-31, while the disable flag is bit 27
if I recall.

Specifically bit 31 is read only, bit 28 will clear bit 31, bit 29
will cause the crashlog to be generated and set bit 31, and bit 30 is
just reserved 0.

> ...
>
> > +       /* clear control bits */
>
> Ditto. And moreover it's ambiguous due to joined two lines below.

I'll just drop the comments.

> > +       control &= ~CRASHLOG_FLAG_MASK;
> > +       control |= CRASHLOG_FLAG_EXECUTE;
>
> ...
>
> > +       return strnlen(buf, count);
>
> How is this different to count?

I guess they should be equivalent so I can probably just switch to count.

> ...
>
> > +       struct crashlog_entry *entry;
> > +       bool trigger;
> > +       int result;
> > +
>
> > +       entry = dev_get_drvdata(dev);
>
> You may reduce LOCs by direct assigning in the definition block above.

Okay. I can move it if you prefer.

> ...
>
> > +       result = strnlen(buf, count);
>
> How is it different from count?

I'll switch it.

> ...
>
> > +static DEFINE_XARRAY_ALLOC(crashlog_array);
> > +static struct intel_pmt_namespace pmt_crashlog_ns = {
> > +       .name = "crashlog",
> > +       .xa = &crashlog_array,
> > +       .attr_grp = &pmt_crashlog_group
>
> Leave the comma here.

Already fixed based on similar comments you had for the telemetry driver.. :-)

> > +};
>
> ...
>
> > +       ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, parent);
> > +       if (!ret)
> > +               return 0;
> > +
> > +       dev_err(parent, "Failed to add crashlog controls\n");
> > +       intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
> > +
> > +       return ret;
>
> Can we use traditional patterns?
> if (ret) {
>   ...
> }
> return ret;

I can switch it if that is preferred.

> ...
>
> > +       size = offsetof(struct pmt_crashlog_priv, entry[pdev->num_resources]);
> > +       priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
> > +       if (!priv)
> > +               return -ENOMEM;
>
> struct_size()
>
> ...
>
> > +               /* initialize control mutex */
> > +               mutex_init(&priv->entry[i].control_mutex);
> > +
> > +               disc_res = platform_get_resource(pdev, IORESOURCE_MEM, i);
> > +               if (!disc_res)
> > +                       goto abort_probe;
> > +
> > +               ret = intel_pmt_ioremap_discovery_table(entry, pdev, i);
> > +               if (ret)
> > +                       goto abort_probe;
> > +
> > +               if (!pmt_crashlog_supported(entry))
> > +                       continue;
> > +
> > +               ret = pmt_crashlog_add_entry(entry, &pdev->dev, disc_res);
> > +               if (ret)
> > +                       goto abort_probe;
> > +
> > +               priv->num_entries++;
>
> Are you going to duplicate this in each driver? Consider to refactor
> to avoid duplication of a lot of code.

So the issue lies in the complexity of pmt_telem_add_entry versus
pmt_crashlog_add_entry. Specifically I end up needing disc_res and the
discovery table when I go to create the controls for the crashlog
device. Similarly we have a third device that we plan to add called a
watcher which will require us to keep things split up like this so we
thought it best to split it up this way.

> ...
>
> > +               .name   = DRV_NAME,
>
> > +MODULE_ALIAS("platform:" DRV_NAME);
>
> I'm not sure I have interpreted this:
>         - Use 'raw' string instead of defines for device names
> correctly. Can you elaborate?

Again I am not sure what this is in reference to. If you can point me
to some documentation somewhere I can take a look.

Thanks.

- Alex
Andy Shevchenko Oct. 1, 2020, 6:46 p.m. UTC | #3
On Thu, Oct 1, 2020 at 9:33 PM Alexander Duyck
<alexander.duyck@gmail.com> wrote:
> On Thu, Oct 1, 2020 at 9:37 AM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Thu, Oct 1, 2020 at 4:43 AM David E. Box <david.e.box@linux.intel.com> wrote:

...

> Arguably not much. I'll drop the comment.
>
> > > +       control &= ~(CRASHLOG_FLAG_MASK | CRASHLOG_FLAG_DISABLE);
> >
> > How does the second constant play any role here?
>
> The "control" flags are bits 28-31, while the disable flag is bit 27
> if I recall.

Okay, then it adds more confusion to the same comment here and there.
Good you are about to drop the comment.

> Specifically bit 31 is read only, bit 28 will clear bit 31, bit 29
> will cause the crashlog to be generated and set bit 31, and bit 30 is
> just reserved 0.

Can this be added as a comment somewhere in the code?

...

> > > +       ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, parent);
> > > +       if (!ret)
> > > +               return 0;

(2)

> > > +
> > > +       dev_err(parent, "Failed to add crashlog controls\n");
> > > +       intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
> > > +
> > > +       return ret;
> >
> > Can we use traditional patterns?
> > if (ret) {
> >   ...
> > }
> > return ret;
>
> I can switch it if that is preferred.

Yes, please. The (2) is really hard to parse (easy to miss ! part and
be confused by return 0 one).

...

> > Are you going to duplicate this in each driver? Consider to refactor
> > to avoid duplication of a lot of code.
>
> So the issue lies in the complexity of pmt_telem_add_entry versus
> pmt_crashlog_add_entry. Specifically I end up needing disc_res and the
> discovery table when I go to create the controls for the crashlog
> device. Similarly we have a third device that we plan to add called a
> watcher which will require us to keep things split up like this so we
> thought it best to split it up this way.

Could you revisit and think how this can be deduplicated. I see at
least one variant with a hooks (callbacks) which you supply depending
on the driver, but the for-loop is kept in one place.

...

> > > +               .name   = DRV_NAME,
> >
> > > +MODULE_ALIAS("platform:" DRV_NAME);
> >
> > I'm not sure I have interpreted this:
> >         - Use 'raw' string instead of defines for device names
> > correctly. Can you elaborate?
>
> Again I am not sure what this is in reference to. If you can point me
> to some documentation somewhere I can take a look.

Reference to your own changelog of this series!
Alexander Duyck Oct. 1, 2020, 7:15 p.m. UTC | #4
On Thu, Oct 1, 2020 at 11:47 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Oct 1, 2020 at 9:33 PM Alexander Duyck
> <alexander.duyck@gmail.com> wrote:
> > On Thu, Oct 1, 2020 at 9:37 AM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> > > On Thu, Oct 1, 2020 at 4:43 AM David E. Box <david.e.box@linux.intel.com> wrote:
>
> ...
>
> > Arguably not much. I'll drop the comment.
> >
> > > > +       control &= ~(CRASHLOG_FLAG_MASK | CRASHLOG_FLAG_DISABLE);
> > >
> > > How does the second constant play any role here?
> >
> > The "control" flags are bits 28-31, while the disable flag is bit 27
> > if I recall.
>
> Okay, then it adds more confusion to the same comment here and there.
> Good you are about to drop the comment.
>
> > Specifically bit 31 is read only, bit 28 will clear bit 31, bit 29
> > will cause the crashlog to be generated and set bit 31, and bit 30 is
> > just reserved 0.
>
> Can this be added as a comment somewhere in the code?

I'll do that with the definitions themselves.

> ...
>
> > > > +       ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, parent);
> > > > +       if (!ret)
> > > > +               return 0;
>
> (2)
>
> > > > +
> > > > +       dev_err(parent, "Failed to add crashlog controls\n");
> > > > +       intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
> > > > +
> > > > +       return ret;
> > >
> > > Can we use traditional patterns?
> > > if (ret) {
> > >   ...
> > > }
> > > return ret;
> >
> > I can switch it if that is preferred.
>
> Yes, please. The (2) is really hard to parse (easy to miss ! part and
> be confused by return 0 one).
>
> ...
>
> > > Are you going to duplicate this in each driver? Consider to refactor
> > > to avoid duplication of a lot of code.
> >
> > So the issue lies in the complexity of pmt_telem_add_entry versus
> > pmt_crashlog_add_entry. Specifically I end up needing disc_res and the
> > discovery table when I go to create the controls for the crashlog
> > device. Similarly we have a third device that we plan to add called a
> > watcher which will require us to keep things split up like this so we
> > thought it best to split it up this way.
>
> Could you revisit and think how this can be deduplicated. I see at
> least one variant with a hooks (callbacks) which you supply depending
> on the driver, but the for-loop is kept in one place.

I'll see what I can do.

> ...
>
> > > > +               .name   = DRV_NAME,
> > >
> > > > +MODULE_ALIAS("platform:" DRV_NAME);
> > >
> > > I'm not sure I have interpreted this:
> > >         - Use 'raw' string instead of defines for device names
> > > correctly. Can you elaborate?
> >
> > Again I am not sure what this is in reference to. If you can point me
> > to some documentation somewhere I can take a look.
>
> Reference to your own changelog of this series!

So the issue is we have two authors so it is a matter of keeping track
of who is working on what.

So apparently that was in reference to the MFD driver which was
instantiating the devices using defines and there was only one spot
where they were being used. The reason why I was confused is because
the commit message had nothing to do with this patch and it I haven't
really done any work on the MFD driver myself. The link to the 'raw'
discussion can be found here:
https://lore.kernel.org/lkml/20200728075859.GH1850026@dell/
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-class-intel_pmt b/Documentation/ABI/testing/sysfs-class-intel_pmt
index 926b5cf95fd1..67ca47123cbf 100644
--- a/Documentation/ABI/testing/sysfs-class-intel_pmt
+++ b/Documentation/ABI/testing/sysfs-class-intel_pmt
@@ -52,3 +52,68 @@  Contact:	David Box <david.e.box@linux.intel.com>
 Description:
 		(RO) The offset of telemetry region in bytes that corresponds to
 		the mapping for the telem file.
+
+What:		/sys/class/intel_pmt/crashlog<x>
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		The crashlog<x> directory contains files for configuring an
+		instance of a PMT crashlog device that can perform crash data
+		recoring. Each crashlog<x> device has an associated crashlog
+		file. This file can be opened and mapped or read to access the
+		resulting crashlog buffer. The register layout for the buffer
+		can be determined from an XML file of specified guid for the
+		parent device.
+
+What:		/sys/class/intel_pmt/crashlog<x>/crashlog
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	David Box <david.e.box@linux.intel.com>
+Description:
+		(RO) The crashlog buffer for this crashlog device. This file
+		may be mapped or read to obtain the data.
+
+What:		/sys/class/intel_pmt/crashlog<x>/guid
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		(RO) The guid for this crashlog device. The guid identifies the
+		version of the XML file for the parent device that should be
+		used to determine the register layout.
+
+What:		/sys/class/intel_pmt/crashlog<x>/size
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		(RO) The length of the result buffer in bytes that corresponds
+		to the size for the crashlog buffer.
+
+What:		/sys/class/intel_pmt/crashlog<x>/offset
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		(RO) The offset of the buffer in bytes that corresponds
+		to the mapping for the crashlog device.
+
+What:		/sys/class/intel_pmt/crashlog<x>/enable
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		(RW) Boolean value controlling if the crashlog functionality
+		is enabled for the crashlog device.
+
+What:		/sys/class/intel_pmt/crashlog<x>/trigger
+Date:		October 2020
+KernelVersion:	5.10
+Contact:	Alexander Duyck <alexander.h.duyck@linux.intel.com>
+Description:
+		(RW) Boolean value controlling the triggering of the crashlog
+		device node. When read it provides data on if the crashlog has
+		been triggered. When written to it can be used to either clear
+		the current trigger by writing false, or to trigger a new
+		event if the trigger is not currently set.
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 8eae17a57a5b..529c5ee2eabf 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1377,6 +1377,14 @@  config INTEL_PMT_TELEMETRY
 	  access to hardware telemetry metrics on devices that support the
 	  feature.
 
+config INTEL_PMT_CRASHLOG
+	tristate "Intel Platform Monitoring Technology (PMT) Crashlog driver"
+	select INTEL_PMT_CLASS
+	help
+	  The Intel Platform Monitoring Technology (PMT) crashlog driver provides
+	  access to hardware crashlog capabilities on devices that support the
+	  feature.
+
 config INTEL_PUNIT_IPC
 	tristate "Intel P-Unit IPC Driver"
 	help
diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
index 6a7b61f59ea8..ca82c1344977 100644
--- a/drivers/platform/x86/Makefile
+++ b/drivers/platform/x86/Makefile
@@ -142,6 +142,7 @@  obj-$(CONFIG_INTEL_MRFLD_PWRBTN)	+= intel_mrfld_pwrbtn.o
 obj-$(CONFIG_INTEL_PMC_CORE)		+= intel_pmc_core.o intel_pmc_core_pltdrv.o
 obj-$(CONFIG_INTEL_PMT_CLASS)		+= intel_pmt_class.o
 obj-$(CONFIG_INTEL_PMT_TELEMETRY)	+= intel_pmt_telemetry.o
+obj-$(CONFIG_INTEL_PMT_CRASHLOG)	+= intel_pmt_crashlog.o
 obj-$(CONFIG_INTEL_PUNIT_IPC)		+= intel_punit_ipc.o
 obj-$(CONFIG_INTEL_SCU_IPC)		+= intel_scu_ipc.o
 obj-$(CONFIG_INTEL_SCU_PCI)		+= intel_scu_pcidrv.o
diff --git a/drivers/platform/x86/intel_pmt_crashlog.c b/drivers/platform/x86/intel_pmt_crashlog.c
new file mode 100644
index 000000000000..9c77be39ac16
--- /dev/null
+++ b/drivers/platform/x86/intel_pmt_crashlog.c
@@ -0,0 +1,339 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel Platform Monitoring Technology Crashlog driver
+ *
+ * Copyright (c) 2020, Intel Corporation.
+ * All Rights Reserved.
+ *
+ * Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "intel_pmt_class.h"
+
+#define DRV_NAME		"pmt_crashlog"
+
+/* Crashlog discovery header types */
+#define CRASH_TYPE_OOBMSM	1
+
+/* Control Flags */
+#define CRASHLOG_FLAG_DISABLE	BIT(27)
+#define CRASHLOG_FLAG_CLEAR	BIT(28)
+#define CRASHLOG_FLAG_EXECUTE	BIT(29)
+#define CRASHLOG_FLAG_COMPLETE	BIT(31)
+#define CRASHLOG_FLAG_MASK	GENMASK(31, 28)
+
+/* Crashlog Discovery Header */
+#define CONTROL_OFFSET		0x0
+#define GUID_OFFSET		0x4
+#define BASE_OFFSET		0x8
+#define SIZE_OFFSET		0xC
+#define GET_ACCESS(v)		((v) & GENMASK(3, 0))
+#define GET_TYPE(v)		(((v) & GENMASK(7, 4)) >> 4)
+#define GET_VERSION(v)		(((v) & GENMASK(19, 16)) >> 16)
+/* size is in bytes */
+#define GET_SIZE(v)		((v) * sizeof(u32))
+
+struct crashlog_entry {
+	/* entry must be first member of struct */
+	struct intel_pmt_entry		entry;
+	struct mutex			control_mutex;
+};
+
+struct pmt_crashlog_priv {
+	int			num_entries;
+	struct crashlog_entry	entry[];
+};
+
+/*
+ * I/O
+ */
+static bool pmt_crashlog_complete(struct intel_pmt_entry *entry)
+{
+	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+	/* return current value of the crashlog complete flag */
+	return !!(control & CRASHLOG_FLAG_COMPLETE);
+}
+
+static bool pmt_crashlog_disabled(struct intel_pmt_entry *entry)
+{
+	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+	/* return current value of the crashlog disabled flag */
+	return !!(control & CRASHLOG_FLAG_DISABLE);
+}
+
+static bool pmt_crashlog_supported(struct intel_pmt_entry *entry)
+{
+	u32 discovery_header = readl(entry->disc_table + CONTROL_OFFSET);
+	u32 crash_type, version;
+
+	crash_type = GET_TYPE(discovery_header);
+	version = GET_VERSION(discovery_header);
+
+	/*
+	 * Currenty we only recognize OOBMSM version 0 devices.
+	 * We can ignore all other crashlog devices in the system.
+	 */
+	return crash_type == CRASH_TYPE_OOBMSM && version == 0;
+}
+
+static void pmt_crashlog_set_disable(struct intel_pmt_entry *entry,
+				     bool disable)
+{
+	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+	/* clear control bits */
+	control &= ~(CRASHLOG_FLAG_MASK | CRASHLOG_FLAG_DISABLE);
+	if (disable)
+		control |= CRASHLOG_FLAG_DISABLE;
+
+	writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+static void pmt_crashlog_set_clear(struct intel_pmt_entry *entry)
+{
+	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+	/* clear control bits */
+	control &= ~CRASHLOG_FLAG_MASK;
+	control |= CRASHLOG_FLAG_CLEAR;
+
+	writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+static void pmt_crashlog_set_execute(struct intel_pmt_entry *entry)
+{
+	u32 control = readl(entry->disc_table + CONTROL_OFFSET);
+
+	/* clear control bits */
+	control &= ~CRASHLOG_FLAG_MASK;
+	control |= CRASHLOG_FLAG_EXECUTE;
+
+	writel(control, entry->disc_table + CONTROL_OFFSET);
+}
+
+/*
+ * sysfs
+ */
+static ssize_t
+enable_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct intel_pmt_entry *entry;
+	int enabled;
+
+	entry = dev_get_drvdata(dev);
+	enabled = !pmt_crashlog_disabled(entry);
+
+	return sprintf(buf, "%d\n", enabled);
+}
+
+static ssize_t
+enable_store(struct device *dev, struct device_attribute *attr,
+	    const char *buf, size_t count)
+{
+	struct crashlog_entry *entry;
+	bool enabled;
+	int result;
+
+	entry = dev_get_drvdata(dev);
+
+	result = kstrtobool(buf, &enabled);
+	if (result)
+		return result;
+
+	mutex_lock(&entry->control_mutex);
+	pmt_crashlog_set_disable(&entry->entry, !enabled);
+	mutex_unlock(&entry->control_mutex);
+
+	return strnlen(buf, count);
+}
+static DEVICE_ATTR_RW(enable);
+
+static ssize_t
+trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct intel_pmt_entry *entry;
+	int trigger;
+
+	entry = dev_get_drvdata(dev);
+	trigger = pmt_crashlog_complete(entry);
+
+	return sprintf(buf, "%d\n", trigger);
+}
+
+static ssize_t
+trigger_store(struct device *dev, struct device_attribute *attr,
+	    const char *buf, size_t count)
+{
+	struct crashlog_entry *entry;
+	bool trigger;
+	int result;
+
+	entry = dev_get_drvdata(dev);
+
+	result = kstrtobool(buf, &trigger);
+	if (result)
+		return result;
+
+	mutex_lock(&entry->control_mutex);
+
+	if (!trigger) {
+		pmt_crashlog_set_clear(&entry->entry);
+	} else if (pmt_crashlog_complete(&entry->entry)) {
+		/* we cannot trigger a new crash if one is still pending */
+		result = -EEXIST;
+		goto err;
+	} else if (pmt_crashlog_disabled(&entry->entry)) {
+		/* if device is currently disabled, return busy */
+		result = -EBUSY;
+		goto err;
+	} else {
+		pmt_crashlog_set_execute(&entry->entry);
+	}
+
+	result = strnlen(buf, count);
+err:
+	mutex_unlock(&entry->control_mutex);
+	return result;
+}
+static DEVICE_ATTR_RW(trigger);
+
+static struct attribute *pmt_crashlog_attrs[] = {
+	&dev_attr_enable.attr,
+	&dev_attr_trigger.attr,
+	NULL
+};
+
+static struct attribute_group pmt_crashlog_group = {
+	.attrs	= pmt_crashlog_attrs,
+};
+
+static DEFINE_XARRAY_ALLOC(crashlog_array);
+static struct intel_pmt_namespace pmt_crashlog_ns = {
+	.name = "crashlog",
+	.xa = &crashlog_array,
+	.attr_grp = &pmt_crashlog_group
+};
+
+/*
+ * initialization
+ */
+static int pmt_crashlog_add_entry(struct intel_pmt_entry *entry,
+				  struct device *parent,
+				  struct resource *disc_res)
+{
+	void __iomem *disc_table = entry->disc_table;
+	struct intel_pmt_header header;
+	int ret;
+
+	header.access_type = GET_ACCESS(readl(disc_table));
+	header.guid = readl(disc_table + GUID_OFFSET);
+	header.base_offset = readl(disc_table + BASE_OFFSET);
+
+	/* Size is measured in DWORDS, but accessor returns bytes */
+	header.size = GET_SIZE(readl(disc_table + SIZE_OFFSET));
+
+	ret = intel_pmt_populate_entry(entry, &header, parent, disc_res);
+	if (ret)
+		return ret;
+
+	ret = intel_pmt_dev_create(entry, &pmt_crashlog_ns, parent);
+	if (!ret)
+		return 0;
+
+	dev_err(parent, "Failed to add crashlog controls\n");
+	intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
+
+	return ret;
+}
+
+static int pmt_crashlog_remove(struct platform_device *pdev)
+{
+	struct pmt_crashlog_priv *priv = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < priv->num_entries; i++)
+		intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
+
+	return 0;
+}
+
+static int pmt_crashlog_probe(struct platform_device *pdev)
+{
+	struct pmt_crashlog_priv *priv;
+	size_t size;
+	int i, ret;
+
+	size = offsetof(struct pmt_crashlog_priv, entry[pdev->num_resources]);
+	priv = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, priv);
+
+	for (i = 0; i < pdev->num_resources; i++) {
+		struct intel_pmt_entry *entry = &priv->entry[i].entry;
+		struct resource	*disc_res;
+
+		ret = -ENODEV;
+
+		/* initialize control mutex */
+		mutex_init(&priv->entry[i].control_mutex);
+
+		disc_res = platform_get_resource(pdev, IORESOURCE_MEM, i);
+		if (!disc_res)
+			goto abort_probe;
+
+		ret = intel_pmt_ioremap_discovery_table(entry, pdev, i);
+		if (ret)
+			goto abort_probe;
+
+		if (!pmt_crashlog_supported(entry))
+			continue;
+
+		ret = pmt_crashlog_add_entry(entry, &pdev->dev, disc_res);
+		if (ret)
+			goto abort_probe;
+
+		priv->num_entries++;
+	}
+
+	return 0;
+abort_probe:
+	pmt_crashlog_remove(pdev);
+	return ret;
+}
+
+static struct platform_driver pmt_crashlog_driver = {
+	.driver = {
+		.name   = DRV_NAME,
+	},
+	.remove = pmt_crashlog_remove,
+	.probe  = pmt_crashlog_probe,
+};
+
+static int __init pmt_crashlog_init(void)
+{
+	return platform_driver_register(&pmt_crashlog_driver);
+}
+
+static void __exit pmt_crashlog_exit(void)
+{
+	platform_driver_unregister(&pmt_crashlog_driver);
+	xa_destroy(&crashlog_array);
+}
+
+module_init(pmt_crashlog_init);
+module_exit(pmt_crashlog_exit);
+
+MODULE_AUTHOR("Alexander Duyck <alexander.h.duyck@linux.intel.com>");
+MODULE_DESCRIPTION("Intel PMT Crashlog driver");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_LICENSE("GPL v2");