RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Hubbe, Allen]

From: Xiangliang Yu [mailto:Xiangliang.Yu@amd.com]
> This adds support for AMD's PCI-Express Non-Transparent Bridge
> (NTB) device on the Zeppelin platform. The driver connnects to the
> standard NTB sub-system interface, with modification to add hooks
> for power management in a separate patch. The AMD NTB device has 3
> memory windows, 16 doorbell, 16 scratch-pad registers, and supports
> up to 16 PCIe lanes running a Gen3 speeds.
> 
> Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>


> Signed-off-by: Jon Mason <jdmason@kudzu.us>
> Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>

Hold on a sec... what?  Who?  I don't remember signing off on this.

Signed-off-by has legal implications with regards to the developer certificate of origin.  Please don't just put names on stuff!  It's forgery!

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Yu, Xiangliang]

> -----Original Message-----
> From: Hubbe, Allen [mailto:Allen.Hubbe@emc.com]
> Sent: Thursday, January 21, 2016 11:54 AM
> To: Yu, Xiangliang; jdmason@kudzu.us; dave.jiang@intel.com; linux-
> kernel@vger.kernel.org; linux-ntb@googlegroups.com
> Cc: SPG_Linux_Kernel
> Subject: RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-
> Transparent Bridge
> 
> From: Xiangliang Yu [mailto:Xiangliang.Yu@amd.com]
> > This adds support for AMD's PCI-Express Non-Transparent Bridge
> > (NTB) device on the Zeppelin platform. The driver connnects to the
> > standard NTB sub-system interface, with modification to add hooks for
> > power management in a separate patch. The AMD NTB device has 3
> memory
> > windows, 16 doorbell, 16 scratch-pad registers, and supports up to 16
> > PCIe lanes running a Gen3 speeds.
> >
> > Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
> 
> 
> > Signed-off-by: Jon Mason <jdmason@kudzu.us>
> > Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
> 
> Hold on a sec... what?  Who?  I don't remember signing off on this.
> 
> Signed-off-by has legal implications with regards to the developer certificate
> of origin.  Please don't just put names on stuff!  It's forgery!

Please help change it to reviewer-by when applying it. Thanks!

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Allen Hubbe]

From: Xiangliang Yu <Xiangliang.Yu@amd.com>
> This adds support for AMD's PCI-Express Non-Transparent Bridge
> (NTB) device on the Zeppelin platform. The driver connnects to the
> standard NTB sub-system interface, with modification to add hooks
> for power management in a separate patch. The AMD NTB device has 3
> memory windows, 16 doorbell, 16 scratch-pad registers, and supports
> up to 16 PCIe lanes running a Gen3 speeds.
> 
> Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>

> Signed-off-by: Jon Mason <jdmason@kudzu.us>
> Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>

NO.


> +		/* set and verify setting the translation address */
> +		write64(addr, peer_mmio + xlat_reg);
> +		reg_val = read64(peer_mmio + xlat_reg);
> +		if (reg_val != addr) {
> +			write64(0, peer_mmio + xlat_reg);
> +			return -EIO;
> +		}
> +
> +		/* set and verify setting the limit */
> +		writel(limit, mmio + limit_reg);
> +		reg_val = readl(mmio + limit_reg);
> +		if (reg_val != limit) {
> +			writel(base_addr, mmio + limit_reg);
> +			writel(0, peer_mmio + xlat_reg);
> +			return -EIO;
> +		}

I see what you did there, change iowrite64 to write64.

What I meant was:
 - change readl to ioread32.
 - change writel to iowrite32.
 - change readb, readw, writeb, writew (if there are any)
 - leave ioread64 and iowrite64 as they were.

Why: http://www.makelinux.net/ldd3/chp-9-sect-4

Quote: "If you read through the kernel source, you see many calls to an older set of functions when I/O memory is being used. These functions still work, but their use in new code is discouraged. Among other things, they are less safe because they do not perform the same sort of type checking."

The "older set of functions" are read[bwl], write[bwl].  This is a new driver, with all new code.  Please use the ioread/iowrite variants.

> +static int amd_link_is_up(struct amd_ntb_dev *ndev)
> +{
> +	if (!ndev->peer_sta)
> +		return NTB_LNK_STA_ACTIVE(ndev->cntl_sta);
> +
> +	/* If peer_sta is reset or D0 event, the ISR has
> +	 * started a timer to check link status of hardware.
> +	 * So here just clear status bit. And if peer_sta is
> +	 * D3 or PME_TO, D0/reset event will be happened when
> +	 * system wakeup/poweron, so do nothing here.
> +	 */
> +	if (ndev->peer_sta & AMD_PEER_RESET_EVENT)
> +		ndev->peer_sta &= ~AMD_PEER_RESET_EVENT;
> +	else if (ndev->peer_sta & AMD_PEER_D0_EVENT)
> +		ndev->peer_sta = 0;
> +
> +	return 0;
> +}

Thanks.  This is much better.

> +static void amd_handle_event(struct amd_ntb_dev *ndev, int vec)
...
> +	case AMD_PEER_D0_EVENT:
...
> +		/* start a timer to poll link status */
> +		schedule_delayed_work(&ndev->hb_timer,
> +					      AMD_LINK_HB_TIMEOUT);

This is different from v4.  It used to be:

if (amd_link_is_up())
	ntb_link_event();
else
	schedule_delayed_work();

Why is v5 correct?
Why was v4 incorrect?

I'm nervous about ndev->peer_sta, the behavior of link_is_up, timers... unexplained changes to a fragile bit of code - not just this code, but any code that deals with parallel or asynchronous behaviors.  With the comment in link_is_up, this code is much better, but any changes to this whole link state mechanism need to be explained.


Allen

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Yu, Xiangliang]

> From: Xiangliang Yu <Xiangliang.Yu@amd.com>
> > This adds support for AMD's PCI-Express Non-Transparent Bridge
> > (NTB) device on the Zeppelin platform. The driver connnects to the
> > standard NTB sub-system interface, with modification to add hooks for
> > power management in a separate patch. The AMD NTB device has 3
> memory
> > windows, 16 doorbell, 16 scratch-pad registers, and supports up to 16
> > PCIe lanes running a Gen3 speeds.
> >
> > Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
> 
> > Signed-off-by: Jon Mason <jdmason@kudzu.us>
> > Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
> 
> NO.

Ok, I'll change it if you doesn't want to change it.

> 
> > +		/* set and verify setting the translation address */
> > +		write64(addr, peer_mmio + xlat_reg);
> > +		reg_val = read64(peer_mmio + xlat_reg);
> > +		if (reg_val != addr) {
> > +			write64(0, peer_mmio + xlat_reg);
> > +			return -EIO;
> > +		}
> > +
> > +		/* set and verify setting the limit */
> > +		writel(limit, mmio + limit_reg);
> > +		reg_val = readl(mmio + limit_reg);
> > +		if (reg_val != limit) {
> > +			writel(base_addr, mmio + limit_reg);
> > +			writel(0, peer_mmio + xlat_reg);
> > +			return -EIO;
> > +		}
> 
> I see what you did there, change iowrite64 to write64.
> 
> What I meant was:
>  - change readl to ioread32.
>  - change writel to iowrite32.
>  - change readb, readw, writeb, writew (if there are any)
>  - leave ioread64 and iowrite64 as they were.
> 
> Why: http://www.makelinux.net/ldd3/chp-9-sect-4
> 
> Quote: "If you read through the kernel source, you see many calls to an older
> set of functions when I/O memory is being used. These functions still work,
> but their use in new code is discouraged. Among other things, they are less
> safe because they do not perform the same sort of type checking."
> 
> The "older set of functions" are read[bwl], write[bwl].  This is a new driver,
> with all new code.  Please use the ioread/iowrite variants.

I don’t think so. In here, the i/o memory is only happened when pci_iomap return
Success, so the register can't be accessed through IO port way. And ioread* will
Check if the memory type is mmio type or IO port type (please see the definition).
 I don’t think we need to check It, so I use read* because It can make more efficient. 
I think we need to think about actual usage, not only follow book.
And, I have said it in previous version, I don’t like explain it again, and again.
If you have any concern, please tell me after my comment.

> > +static int amd_link_is_up(struct amd_ntb_dev *ndev) {
> > +	if (!ndev->peer_sta)
> > +		return NTB_LNK_STA_ACTIVE(ndev->cntl_sta);
> > +
> > +	/* If peer_sta is reset or D0 event, the ISR has
> > +	 * started a timer to check link status of hardware.
> > +	 * So here just clear status bit. And if peer_sta is
> > +	 * D3 or PME_TO, D0/reset event will be happened when
> > +	 * system wakeup/poweron, so do nothing here.
> > +	 */
> > +	if (ndev->peer_sta & AMD_PEER_RESET_EVENT)
> > +		ndev->peer_sta &= ~AMD_PEER_RESET_EVENT;
> > +	else if (ndev->peer_sta & AMD_PEER_D0_EVENT)
> > +		ndev->peer_sta = 0;
> > +
> > +	return 0;
> > +}
> 
> Thanks.  This is much better.
> 
> > +static void amd_handle_event(struct amd_ntb_dev *ndev, int vec)
> ...
> > +	case AMD_PEER_D0_EVENT:
> ...
> > +		/* start a timer to poll link status */
> > +		schedule_delayed_work(&ndev->hb_timer,
> > +					      AMD_LINK_HB_TIMEOUT);
> 
> This is different from v4.  It used to be:
> 
> if (amd_link_is_up())
> 	ntb_link_event();
> else
> 	schedule_delayed_work();
> 
> Why is v5 correct?
> Why was v4 incorrect?

Because peer_sta is change to 0, so amd_link_is_up will return 0 (offline)
And will not check hardware link status. So It maybe make it offline forever

> I'm nervous about ndev->peer_sta, the behavior of link_is_up, timers...
> unexplained changes to a fragile bit of code - not just this code, but any code
> that deals with parallel or asynchronous behaviors.  With the comment in
> link_is_up, this code is much better, but any changes to this whole link state
> mechanism need to be explained.
Actually, the code is designed according to Atom NTB, except for the peer_sta. 
I'll add the explaination when having changes.

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Allen Hubbe]

From: Yu, Xiangliang [mailto:Xiangliang.Yu@amd.com]
> > > Signed-off-by: Jon Mason <jdmason@kudzu.us>
> > > Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
> >
> > NO.
> 
> Ok, I'll change it if you doesn't want to change it.

Nah, just remember it for next time...

I'm satisfied with this v5.

Reviewed-by: Allen Hubbe <Allen.Hubbe@emc.com>

> I don’t think so. In here, the i/o memory is only happened when
> pci_iomap return
> Success, so the register can't be accessed through IO port way. And
> ioread* will
> Check if the memory type is mmio type or IO port type (please see the
> definition).
>  I don’t think we need to check It, so I use read* because It can make
> more efficient.
> I think we need to think about actual usage, not only follow book.
> And, I have said it in previous version, I don’t like explain it again,
> and again.
> If you have any concern, please tell me after my comment.

It's not more efficient, on this platform it's the same.

If it were my driver I would change it... but you can keep it this way.

> > This is different from v4.  It used to be:
> 
> Because peer_sta is change to 0, so amd_link_is_up will return 0
> (offline)
> And will not check hardware link status. So It maybe make it offline
> forever

It fixed a bug?  Great!

> > I'm nervous about ndev->peer_sta, the behavior of link_is_up,
> > timers...
>
> Actually, the code is designed according to Atom NTB, except for the
> peer_sta.

Except for peer_sta, and that's a pretty critical design change.  I'm still nervous, but I'll trust that you have been able to test this behavior thourougly.

> I'll add the explaination when having changes.

Thanks.

Allen

RE: [PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Yu, Xiangliang]

> From: Yu, Xiangliang [mailto:Xiangliang.Yu@amd.com]
> > > > Signed-off-by: Jon Mason <jdmason@kudzu.us>
> > > > Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
> > >
> > > NO.
> >
> > Ok, I'll change it if you doesn't want to change it.
> 
> Nah, just remember it for next time...
> 
> I'm satisfied with this v5.
> 
> Reviewed-by: Allen Hubbe <Allen.Hubbe@emc.com>

Ok, I'll change it and resend V5

> > I don’t think so. In here, the i/o memory is only happened when
> > pci_iomap return Success, so the register can't be accessed through IO
> > port way. And
> > ioread* will
> > Check if the memory type is mmio type or IO port type (please see the
> > definition).
> >  I don’t think we need to check It, so I use read* because It can make
> > more efficient.
> > I think we need to think about actual usage, not only follow book.
> > And, I have said it in previous version, I don’t like explain it
> > again, and again.
> > If you have any concern, please tell me after my comment.
> 
> It's not more efficient, on this platform it's the same.
> 
> If it were my driver I would change it... but you can keep it this way.

Because my previous SATA experience, I'd like to use this way.

> > > This is different from v4.  It used to be:
> >
> > Because peer_sta is change to 0, so amd_link_is_up will return 0
> > (offline)
> > And will not check hardware link status. So It maybe make it offline
> > forever
> 
> It fixed a bug?  Great!
> 
> > > I'm nervous about ndev->peer_sta, the behavior of link_is_up,
> > > timers...
> >
> > Actually, the code is designed according to Atom NTB, except for the
> > peer_sta.
> 
> Except for peer_sta, and that's a pretty critical design change.  I'm still
> nervous, but I'll trust that you have been able to test this behavior
> thourougly.

Yes, the part of code will be changed in future because hardware design is
Being changed  too.

> 
> > I'll add the explaination when having changes.

[PATCH V5 1/1] NTB: Add support for AMD PCI-Express Non-Transparent Bridge

[Xiangliang Yu]

This adds support for AMD's PCI-Express Non-Transparent Bridge
(NTB) device on the Zeppelin platform. The driver connnects to the
standard NTB sub-system interface, with modification to add hooks
for power management in a separate patch. The AMD NTB device has 3
memory windows, 16 doorbell, 16 scratch-pad registers, and supports
up to 16 PCIe lanes running a Gen3 speeds.

Signed-off-by: Xiangliang Yu <Xiangliang.Yu@amd.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Allen Hubbe <Allen.Hubbe@emc.com>
---
 MAINTAINERS                     |    6 +
 drivers/ntb/hw/Kconfig          |    1 +
 drivers/ntb/hw/Makefile         |    1 +
 drivers/ntb/hw/amd/Kconfig      |    7 +
 drivers/ntb/hw/amd/Makefile     |    1 +
 drivers/ntb/hw/amd/ntb_hw_amd.c | 1143 +++++++++++++++++++++++++++++++++++++++
 drivers/ntb/hw/amd/ntb_hw_amd.h |  217 ++++++++
 7 files changed, 1376 insertions(+)
 create mode 100644 drivers/ntb/hw/amd/Kconfig
 create mode 100644 drivers/ntb/hw/amd/Makefile
 create mode 100644 drivers/ntb/hw/amd/ntb_hw_amd.c
 create mode 100644 drivers/ntb/hw/amd/ntb_hw_amd.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 5192700..908941a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7585,6 +7585,12 @@ W:	https://github.com/jonmason/ntb/wiki
 T:	git git://github.com/jonmason/ntb.git
 F:	drivers/ntb/hw/intel/
 
+NTB AMD DRIVER
+M:	Xiangliang Yu <Xiangliang.Yu@amd.com>
+L:	linux-ntb@googlegroups.com
+S:	Supported
+F:	drivers/ntb/hw/amd/
+
 NTFS FILESYSTEM
 M:	Anton Altaparmakov <anton@tuxera.com>
 L:	linux-ntfs-dev@lists.sourceforge.net
diff --git a/drivers/ntb/hw/Kconfig b/drivers/ntb/hw/Kconfig
index 4d5535c..7116472 100644
--- a/drivers/ntb/hw/Kconfig
+++ b/drivers/ntb/hw/Kconfig
@@ -1 +1,2 @@
+source "drivers/ntb/hw/amd/Kconfig"
 source "drivers/ntb/hw/intel/Kconfig"
diff --git a/drivers/ntb/hw/Makefile b/drivers/ntb/hw/Makefile
index 175d7c9..532e085 100644
--- a/drivers/ntb/hw/Makefile
+++ b/drivers/ntb/hw/Makefile
@@ -1 +1,2 @@
+obj-$(CONFIG_NTB_AMD)	+= amd/
 obj-$(CONFIG_NTB_INTEL)	+= intel/
diff --git a/drivers/ntb/hw/amd/Kconfig b/drivers/ntb/hw/amd/Kconfig
new file mode 100644
index 0000000..cfe903c
--- /dev/null
+++ b/drivers/ntb/hw/amd/Kconfig
@@ -0,0 +1,7 @@
+config NTB_AMD
+	tristate "AMD Non-Transparent Bridge support"
+	depends on X86_64
+	help
+	 This driver supports AMD NTB on capable Zeppelin hardware.
+
+	 If unsure, say N.
diff --git a/drivers/ntb/hw/amd/Makefile b/drivers/ntb/hw/amd/Makefile
new file mode 100644
index 0000000..ad54da9
--- /dev/null
+++ b/drivers/ntb/hw/amd/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_NTB_AMD) += ntb_hw_amd.o
diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.c b/drivers/ntb/hw/amd/ntb_hw_amd.c
new file mode 100644
index 0000000..d484829
--- /dev/null
+++ b/drivers/ntb/hw/amd/ntb_hw_amd.c
@@ -0,0 +1,1143 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ *   redistributing this file, you may do so under either license.
+ *
+ *   GPL LICENSE SUMMARY
+ *
+ *   Copyright (C) 2016 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of version 2 of the GNU General Public License as
+ *   published by the Free Software Foundation.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright (C) 2016 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copy
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of AMD Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * AMD PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Xiangliang Yu <Xiangliang.Yu@amd.com>
+ */
+
+#include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/ntb.h>
+
+#include "ntb_hw_amd.h"
+
+#define NTB_NAME	"ntb_hw_amd"
+#define NTB_DESC	"AMD(R) PCI-E Non-Transparent Bridge Driver"
+#define NTB_VER		"1.0"
+
+MODULE_DESCRIPTION(NTB_DESC);
+MODULE_VERSION(NTB_VER);
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_AUTHOR("AMD Inc.");
+
+static const struct file_operations amd_ntb_debugfs_info;
+static struct dentry *debugfs_dir;
+
+static int ndev_mw_to_bar(struct amd_ntb_dev *ndev, int idx)
+{
+	if (idx < 0 || idx > ndev->mw_count)
+		return -EINVAL;
+
+	return 1 << idx;
+}
+
+static int amd_ntb_mw_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->mw_count;
+}
+
+static int amd_ntb_mw_get_range(struct ntb_dev *ntb, int idx,
+				phys_addr_t *base,
+				resource_size_t *size,
+				resource_size_t *align,
+				resource_size_t *align_size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	int bar;
+
+	bar = ndev_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	if (base)
+		*base = pci_resource_start(ndev->ntb.pdev, bar);
+
+	if (size)
+		*size = pci_resource_len(ndev->ntb.pdev, bar);
+
+	if (align)
+		*align = SZ_4K;
+
+	if (align_size)
+		*align_size = 1;
+
+	return 0;
+}
+
+static int amd_ntb_mw_set_trans(struct ntb_dev *ntb, int idx,
+				dma_addr_t addr, resource_size_t size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	unsigned long xlat_reg, limit_reg = 0;
+	resource_size_t mw_size;
+	void __iomem *mmio, *peer_mmio;
+	u64 base_addr, limit, reg_val;
+	int bar;
+
+	bar = ndev_mw_to_bar(ndev, idx);
+	if (bar < 0)
+		return bar;
+
+	mw_size = pci_resource_len(ndev->ntb.pdev, bar);
+
+	/* make sure the range fits in the usable mw size */
+	if (size > mw_size)
+		return -EINVAL;
+
+	mmio = ndev->self_mmio;
+	peer_mmio = ndev->peer_mmio;
+
+	base_addr = pci_resource_start(ndev->ntb.pdev, bar);
+
+	if (bar != 1) {
+		xlat_reg = AMD_BAR23XLAT_OFFSET + ((bar - 2) << 3);
+		limit_reg = AMD_BAR23LMT_OFFSET + ((bar - 2) << 3);
+
+		/* Set the limit if supported */
+		limit = base_addr + size;
+
+		/* set and verify setting the translation address */
+		write64(addr, peer_mmio + xlat_reg);
+		reg_val = read64(peer_mmio + xlat_reg);
+		if (reg_val != addr) {
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+
+		/* set and verify setting the limit */
+		write64(limit, mmio + limit_reg);
+		reg_val = read64(mmio + limit_reg);
+		if (reg_val != limit) {
+			write64(base_addr, mmio + limit_reg);
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+	} else {
+		xlat_reg = AMD_BAR1XLAT_OFFSET;
+		limit_reg = AMD_BAR1LMT_OFFSET;
+
+		/* split bar addr range must all be 32 bit */
+		if (addr & (~0ull << 32))
+			return -EINVAL;
+		if ((addr + size) & (~0ull << 32))
+			return -EINVAL;
+
+		/* Set the limit if supported */
+		limit = base_addr + size;
+
+		/* set and verify setting the translation address */
+		write64(addr, peer_mmio + xlat_reg);
+		reg_val = read64(peer_mmio + xlat_reg);
+		if (reg_val != addr) {
+			write64(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+
+		/* set and verify setting the limit */
+		writel(limit, mmio + limit_reg);
+		reg_val = readl(mmio + limit_reg);
+		if (reg_val != limit) {
+			writel(base_addr, mmio + limit_reg);
+			writel(0, peer_mmio + xlat_reg);
+			return -EIO;
+		}
+	}
+
+	return 0;
+}
+
+static int amd_link_is_up(struct amd_ntb_dev *ndev)
+{
+	if (!ndev->peer_sta)
+		return NTB_LNK_STA_ACTIVE(ndev->cntl_sta);
+
+	/* If peer_sta is reset or D0 event, the ISR has
+	 * started a timer to check link status of hardware.
+	 * So here just clear status bit. And if peer_sta is
+	 * D3 or PME_TO, D0/reset event will be happened when
+	 * system wakeup/poweron, so do nothing here.
+	 */
+	if (ndev->peer_sta & AMD_PEER_RESET_EVENT)
+		ndev->peer_sta &= ~AMD_PEER_RESET_EVENT;
+	else if (ndev->peer_sta & AMD_PEER_D0_EVENT)
+		ndev->peer_sta = 0;
+
+	return 0;
+}
+
+static int amd_ntb_link_is_up(struct ntb_dev *ntb,
+			      enum ntb_speed *speed,
+			      enum ntb_width *width)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	int ret = 0;
+
+	if (amd_link_is_up(ndev)) {
+		if (speed)
+			*speed = NTB_LNK_STA_SPEED(ndev->lnk_sta);
+		if (width)
+			*width = NTB_LNK_STA_WIDTH(ndev->lnk_sta);
+
+		dev_dbg(ndev_dev(ndev), "link is up.\n");
+
+		ret = 1;
+	} else {
+		if (speed)
+			*speed = NTB_SPEED_NONE;
+		if (width)
+			*width = NTB_WIDTH_NONE;
+
+		dev_dbg(ndev_dev(ndev), "link is down.\n");
+	}
+
+	return ret;
+}
+
+static int amd_ntb_link_enable(struct ntb_dev *ntb,
+			       enum ntb_speed max_speed,
+			       enum ntb_width max_width)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 ntb_ctl;
+
+	/* Enable event interrupt */
+	ndev->int_mask &= ~AMD_EVENT_INTMASK;
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	if (ndev->ntb.topo == NTB_TOPO_SEC)
+		return -EINVAL;
+	dev_dbg(ndev_dev(ndev), "Enabling Link.\n");
+
+	ntb_ctl = readl(mmio + AMD_CNTL_OFFSET);
+	ntb_ctl |= (PMM_REG_CTL | SMM_REG_CTL);
+	writel(ntb_ctl, mmio + AMD_CNTL_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_link_disable(struct ntb_dev *ntb)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 ntb_ctl;
+
+	/* Disable event interrupt */
+	ndev->int_mask |= AMD_EVENT_INTMASK;
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	if (ndev->ntb.topo == NTB_TOPO_SEC)
+		return -EINVAL;
+	dev_dbg(ndev_dev(ndev), "Enabling Link.\n");
+
+	ntb_ctl = readl(mmio + AMD_CNTL_OFFSET);
+	ntb_ctl &= ~(PMM_REG_CTL | SMM_REG_CTL);
+	writel(ntb_ctl, mmio + AMD_CNTL_OFFSET);
+
+	return 0;
+}
+
+static u64 amd_ntb_db_valid_mask(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->db_valid_mask;
+}
+
+static int amd_ntb_db_vector_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->db_count;
+}
+
+static u64 amd_ntb_db_vector_mask(struct ntb_dev *ntb, int db_vector)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (db_vector < 0 || db_vector > ndev->db_count)
+		return 0;
+
+	return ntb_ndev(ntb)->db_valid_mask & (1 << db_vector);
+}
+
+static u64 amd_ntb_db_read(struct ntb_dev *ntb)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	return (u64)readw(mmio + AMD_DBSTAT_OFFSET);
+}
+
+static int amd_ntb_db_clear(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	writew((u16)db_bits, mmio + AMD_DBSTAT_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned long flags;
+
+	if (db_bits & ~ndev->db_valid_mask)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ndev->db_mask_lock, flags);
+	ndev->db_mask |= db_bits;
+	writew((u16)ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+	spin_unlock_irqrestore(&ndev->db_mask_lock, flags);
+
+	return 0;
+}
+
+static int amd_ntb_db_clear_mask(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned long flags;
+
+	if (db_bits & ~ndev->db_valid_mask)
+		return -EINVAL;
+
+	spin_lock_irqsave(&ndev->db_mask_lock, flags);
+	ndev->db_mask &= ~db_bits;
+	writew((u16)ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+	spin_unlock_irqrestore(&ndev->db_mask_lock, flags);
+
+	return 0;
+}
+
+static int amd_ntb_peer_db_addr(struct ntb_dev *ntb,
+				phys_addr_t *db_addr,
+				resource_size_t *db_size)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (db_addr)
+		*db_addr = (phys_addr_t)(ndev->peer_mmio + AMD_DBREQ_OFFSET);
+	if (db_size)
+		*db_size = sizeof(u32);
+
+	return 0;
+}
+
+static int amd_ntb_peer_db_set(struct ntb_dev *ntb, u64 db_bits)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+
+	writew((u16)db_bits, mmio + AMD_DBREQ_OFFSET);
+
+	return 0;
+}
+
+static int amd_ntb_spad_count(struct ntb_dev *ntb)
+{
+	return ntb_ndev(ntb)->spad_count;
+}
+
+static u32 amd_ntb_spad_read(struct ntb_dev *ntb, int idx)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return 0;
+
+	offset = ndev->self_spad + (idx << 2);
+	return readl(mmio + AMD_SPAD_OFFSET + offset);
+}
+
+static int amd_ntb_spad_write(struct ntb_dev *ntb,
+			      int idx, u32 val)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->self_spad + (idx << 2);
+	writel(val, mmio + AMD_SPAD_OFFSET + offset);
+
+	return 0;
+}
+
+static int amd_ntb_peer_spad_addr(struct ntb_dev *ntb, int idx,
+				  phys_addr_t *spad_addr)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	if (spad_addr)
+		*spad_addr = (phys_addr_t)(ndev->self_mmio + AMD_SPAD_OFFSET +
+					   ndev->peer_spad + (idx << 2));
+	return 0;
+}
+
+static u32 amd_ntb_peer_spad_read(struct ntb_dev *ntb, int idx)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->peer_spad + (idx << 2);
+	return readl(mmio + AMD_SPAD_OFFSET + offset);
+}
+
+static int amd_ntb_peer_spad_write(struct ntb_dev *ntb,
+				   int idx, u32 val)
+{
+	struct amd_ntb_dev *ndev = ntb_ndev(ntb);
+	void __iomem *mmio = ndev->self_mmio;
+	u32 offset;
+
+	if (idx < 0 || idx >= ndev->spad_count)
+		return -EINVAL;
+
+	offset = ndev->peer_spad + (idx << 2);
+	writel(val, mmio + AMD_SPAD_OFFSET + offset);
+
+	return 0;
+}
+
+static const struct ntb_dev_ops amd_ntb_ops = {
+	.mw_count		= amd_ntb_mw_count,
+	.mw_get_range		= amd_ntb_mw_get_range,
+	.mw_set_trans		= amd_ntb_mw_set_trans,
+	.link_is_up		= amd_ntb_link_is_up,
+	.link_enable		= amd_ntb_link_enable,
+	.link_disable		= amd_ntb_link_disable,
+	.db_valid_mask		= amd_ntb_db_valid_mask,
+	.db_vector_count	= amd_ntb_db_vector_count,
+	.db_vector_mask		= amd_ntb_db_vector_mask,
+	.db_read		= amd_ntb_db_read,
+	.db_clear		= amd_ntb_db_clear,
+	.db_set_mask		= amd_ntb_db_set_mask,
+	.db_clear_mask		= amd_ntb_db_clear_mask,
+	.peer_db_addr		= amd_ntb_peer_db_addr,
+	.peer_db_set		= amd_ntb_peer_db_set,
+	.spad_count		= amd_ntb_spad_count,
+	.spad_read		= amd_ntb_spad_read,
+	.spad_write		= amd_ntb_spad_write,
+	.peer_spad_addr		= amd_ntb_peer_spad_addr,
+	.peer_spad_read		= amd_ntb_peer_spad_read,
+	.peer_spad_write	= amd_ntb_peer_spad_write,
+};
+
+static void amd_ack_smu(struct amd_ntb_dev *ndev, u32 bit)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	int reg;
+
+	reg = readl(mmio + AMD_SMUACK_OFFSET);
+	reg |= bit;
+	writel(reg, mmio + AMD_SMUACK_OFFSET);
+
+	ndev->peer_sta |= bit;
+}
+
+static void amd_handle_event(struct amd_ntb_dev *ndev, int vec)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	u32 status;
+
+	status = readl(mmio + AMD_INTSTAT_OFFSET);
+	if (!(status & AMD_EVENT_INTMASK))
+		return;
+
+	dev_dbg(ndev_dev(ndev), "status = 0x%x and vec = %d\n", status, vec);
+
+	status &= AMD_EVENT_INTMASK;
+	switch (status) {
+	case AMD_PEER_FLUSH_EVENT:
+		dev_info(ndev_dev(ndev), "Flush is done.\n");
+		break;
+	case AMD_PEER_RESET_EVENT:
+		amd_ack_smu(ndev, AMD_PEER_RESET_EVENT);
+
+		/* link down first */
+		ntb_link_event(&ndev->ntb);
+		/* polling peer status */
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+
+		break;
+	case AMD_PEER_D3_EVENT:
+	case AMD_PEER_PMETO_EVENT:
+		amd_ack_smu(ndev, status);
+
+		/* link down */
+		ntb_link_event(&ndev->ntb);
+
+		break;
+	case AMD_PEER_D0_EVENT:
+		mmio = ndev->peer_mmio;
+		status = readl(mmio + AMD_PMESTAT_OFFSET);
+		/* check if this is WAKEUP event */
+		if (status & 0x1)
+			dev_info(ndev_dev(ndev), "Wakeup is done.\n");
+
+		amd_ack_smu(ndev, AMD_PEER_D0_EVENT);
+
+		/* start a timer to poll link status */
+		schedule_delayed_work(&ndev->hb_timer,
+					      AMD_LINK_HB_TIMEOUT);
+		break;
+	default:
+		dev_info(ndev_dev(ndev), "event status = 0x%x.\n", status);
+		break;
+	}
+}
+
+static irqreturn_t ndev_interrupt(struct amd_ntb_dev *ndev, int vec)
+{
+	dev_dbg(ndev_dev(ndev), "vec %d\n", vec);
+
+	if (vec > (AMD_DB_CNT - 1) || (ndev->msix_vec_count == 1))
+		amd_handle_event(ndev, vec);
+
+	if (vec < AMD_DB_CNT)
+		ntb_db_event(&ndev->ntb, vec);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ndev_vec_isr(int irq, void *dev)
+{
+	struct amd_ntb_vec *nvec = dev;
+
+	return ndev_interrupt(nvec->ndev, nvec->num);
+}
+
+static irqreturn_t ndev_irq_isr(int irq, void *dev)
+{
+	struct amd_ntb_dev *ndev = dev;
+
+	return ndev_interrupt(ndev, irq - ndev_pdev(ndev)->irq);
+}
+
+static int ndev_init_isr(struct amd_ntb_dev *ndev,
+			 int msix_min, int msix_max)
+{
+	struct pci_dev *pdev;
+	int rc, i, msix_count, node;
+
+	pdev = ndev_pdev(ndev);
+
+	node = dev_to_node(&pdev->dev);
+
+	ndev->db_mask = ndev->db_valid_mask;
+
+	/* Try to set up msix irq */
+	ndev->vec = kzalloc_node(msix_max * sizeof(*ndev->vec),
+				 GFP_KERNEL, node);
+	if (!ndev->vec)
+		goto err_msix_vec_alloc;
+
+	ndev->msix = kzalloc_node(msix_max * sizeof(*ndev->msix),
+				  GFP_KERNEL, node);
+	if (!ndev->msix)
+		goto err_msix_alloc;
+
+	for (i = 0; i < msix_max; ++i)
+		ndev->msix[i].entry = i;
+
+	msix_count = pci_enable_msix_range(pdev, ndev->msix,
+					   msix_min, msix_max);
+	if (msix_count < 0)
+		goto err_msix_enable;
+
+	/* NOTE: Disable MSIX if msix count is less than 16 because of
+	 * hardware limitation.
+	 */
+	if (msix_count < msix_min) {
+		pci_disable_msix(pdev);
+		goto err_msix_enable;
+	}
+
+	for (i = 0; i < msix_count; ++i) {
+		ndev->vec[i].ndev = ndev;
+		ndev->vec[i].num = i;
+		rc = request_irq(ndev->msix[i].vector, ndev_vec_isr, 0,
+				 "ndev_vec_isr", &ndev->vec[i]);
+		if (rc)
+			goto err_msix_request;
+	}
+
+	dev_dbg(ndev_dev(ndev), "Using msix interrupts\n");
+	ndev->db_count = msix_min;
+	ndev->msix_vec_count = msix_max;
+	return 0;
+
+err_msix_request:
+	while (i-- > 0)
+		free_irq(ndev->msix[i].vector, ndev);
+	pci_disable_msix(pdev);
+err_msix_enable:
+	kfree(ndev->msix);
+err_msix_alloc:
+	kfree(ndev->vec);
+err_msix_vec_alloc:
+	ndev->msix = NULL;
+	ndev->vec = NULL;
+
+	/* Try to set up msi irq */
+	rc = pci_enable_msi(pdev);
+	if (rc)
+		goto err_msi_enable;
+
+	rc = request_irq(pdev->irq, ndev_irq_isr, 0,
+			 "ndev_irq_isr", ndev);
+	if (rc)
+		goto err_msi_request;
+
+	dev_dbg(ndev_dev(ndev), "Using msi interrupts\n");
+	ndev->db_count = 1;
+	ndev->msix_vec_count = 1;
+	return 0;
+
+err_msi_request:
+	pci_disable_msi(pdev);
+err_msi_enable:
+
+	/* Try to set up intx irq */
+	pci_intx(pdev, 1);
+
+	rc = request_irq(pdev->irq, ndev_irq_isr, IRQF_SHARED,
+			 "ndev_irq_isr", ndev);
+	if (rc)
+		goto err_intx_request;
+
+	dev_dbg(ndev_dev(ndev), "Using intx interrupts\n");
+	ndev->db_count = 1;
+	ndev->msix_vec_count = 1;
+	return 0;
+
+err_intx_request:
+	return rc;
+}
+
+static void ndev_deinit_isr(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev;
+	void __iomem *mmio = ndev->self_mmio;
+	int i;
+
+	pdev = ndev_pdev(ndev);
+
+	/* Mask all doorbell interrupts */
+	ndev->db_mask = ndev->db_valid_mask;
+	writel(ndev->db_mask, mmio + AMD_DBMASK_OFFSET);
+
+	if (ndev->msix) {
+		i = ndev->msix_vec_count;
+		while (i--)
+			free_irq(ndev->msix[i].vector, &ndev->vec[i]);
+		pci_disable_msix(pdev);
+		kfree(ndev->msix);
+		kfree(ndev->vec);
+	} else {
+		free_irq(pdev->irq, ndev);
+		if (pci_dev_msi_enabled(pdev))
+			pci_disable_msi(pdev);
+		else
+			pci_intx(pdev, 0);
+	}
+}
+
+static ssize_t ndev_debugfs_read(struct file *filp, char __user *ubuf,
+				 size_t count, loff_t *offp)
+{
+	struct amd_ntb_dev *ndev;
+	void __iomem *mmio;
+	char *buf;
+	size_t buf_size;
+	ssize_t ret, off;
+	union { u64 v64; u32 v32; u16 v16; } u;
+
+	ndev = filp->private_data;
+	mmio = ndev->self_mmio;
+
+	buf_size = min(count, 0x800ul);
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	off = 0;
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "NTB Device Information:\n");
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Connection Topology -\t%s\n",
+			 ntb_topo_string(ndev->ntb.topo));
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "LNK STA -\t\t%#06x\n", ndev->lnk_sta);
+
+	if (!amd_link_is_up(ndev)) {
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Status -\t\tDown\n");
+	} else {
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Status -\t\tUp\n");
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Speed -\t\tPCI-E Gen %u\n",
+				 NTB_LNK_STA_SPEED(ndev->lnk_sta));
+		off += scnprintf(buf + off, buf_size - off,
+				 "Link Width -\t\tx%u\n",
+				 NTB_LNK_STA_WIDTH(ndev->lnk_sta));
+	}
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Memory Window Count -\t%u\n", ndev->mw_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Scratchpad Count -\t%u\n", ndev->spad_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Count -\t%u\n", ndev->db_count);
+	off += scnprintf(buf + off, buf_size - off,
+			 "MSIX Vector Count -\t%u\n", ndev->msix_vec_count);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Valid Mask -\t%#llx\n", ndev->db_valid_mask);
+
+	u.v32 = readl(ndev->self_mmio + AMD_DBMASK_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Mask -\t\t\t%#06x\n", u.v32);
+
+	u.v32 = readl(mmio + AMD_DBSTAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "Doorbell Bell -\t\t\t%#06x\n", u.v32);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "\nNTB Incoming XLAT:\n");
+
+	u.v64 = read64(mmio + AMD_BAR1XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT1 -\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR23XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT23 -\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR45XLAT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "XLAT45 -\t\t%#018llx\n", u.v64);
+
+	u.v32 = readl(mmio + AMD_BAR1LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT1 -\t\t\t%#06x\n", u.v32);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR23LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT23 -\t\t\t%#018llx\n", u.v64);
+
+	u.v64 = read64(ndev->self_mmio + AMD_BAR45LMT_OFFSET);
+	off += scnprintf(buf + off, buf_size - off,
+			 "LMT45 -\t\t\t%#018llx\n", u.v64);
+
+	ret = simple_read_from_buffer(ubuf, count, offp, buf, off);
+	kfree(buf);
+	return ret;
+}
+
+static void ndev_init_debugfs(struct amd_ntb_dev *ndev)
+{
+	if (!debugfs_dir) {
+		ndev->debugfs_dir = NULL;
+		ndev->debugfs_info = NULL;
+	} else {
+		ndev->debugfs_dir =
+			debugfs_create_dir(ndev_name(ndev), debugfs_dir);
+		if (!ndev->debugfs_dir)
+			ndev->debugfs_info = NULL;
+		else
+			ndev->debugfs_info =
+				debugfs_create_file("info", S_IRUSR,
+						    ndev->debugfs_dir, ndev,
+						    &amd_ntb_debugfs_info);
+	}
+}
+
+static void ndev_deinit_debugfs(struct amd_ntb_dev *ndev)
+{
+	debugfs_remove_recursive(ndev->debugfs_dir);
+}
+
+static inline void ndev_init_struct(struct amd_ntb_dev *ndev,
+				    struct pci_dev *pdev)
+{
+	ndev->ntb.pdev = pdev;
+	ndev->ntb.topo = NTB_TOPO_NONE;
+	ndev->ntb.ops = &amd_ntb_ops;
+	ndev->int_mask = AMD_EVENT_INTMASK;
+	spin_lock_init(&ndev->db_mask_lock);
+}
+
+static int amd_poll_link(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->peer_mmio;
+	u32 reg, stat;
+	int rc;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	reg &= NTB_LIN_STA_ACTIVE_BIT;
+
+	dev_dbg(ndev_dev(ndev), "%s: reg_val = 0x%x.\n", __func__, reg);
+
+	if (reg == ndev->cntl_sta)
+		return 0;
+
+	ndev->cntl_sta = reg;
+
+	rc = pci_read_config_dword(ndev->ntb.pdev,
+				   AMD_LINK_STATUS_OFFSET, &stat);
+	if (rc)
+		return 0;
+	ndev->lnk_sta = stat;
+
+	return 1;
+}
+
+static void amd_link_hb(struct work_struct *work)
+{
+	struct amd_ntb_dev *ndev = hb_ndev(work);
+
+	if (amd_poll_link(ndev))
+		ntb_link_event(&ndev->ntb);
+
+	if (!amd_link_is_up(ndev))
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+}
+
+static int amd_init_isr(struct amd_ntb_dev *ndev)
+{
+	return ndev_init_isr(ndev, AMD_DB_CNT, AMD_MSIX_VECTOR_CNT);
+}
+
+static void amd_init_side_info(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned int reg;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (!(reg & AMD_SIDE_READY)) {
+		reg |= AMD_SIDE_READY;
+		writel(reg, mmio + AMD_SIDEINFO_OFFSET);
+	}
+}
+
+static void amd_deinit_side_info(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	unsigned int reg;
+
+	reg = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (reg & AMD_SIDE_READY) {
+		reg &= ~AMD_SIDE_READY;
+		writel(reg, mmio + AMD_SIDEINFO_OFFSET);
+		readl(mmio + AMD_SIDEINFO_OFFSET);
+	}
+}
+
+static int amd_init_ntb(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+
+	ndev->mw_count = AMD_MW_CNT;
+	ndev->spad_count = AMD_SPADS_CNT;
+	ndev->db_count = AMD_DB_CNT;
+
+	switch (ndev->ntb.topo) {
+	case NTB_TOPO_PRI:
+	case NTB_TOPO_SEC:
+		ndev->spad_count >>= 1;
+		if (ndev->ntb.topo == NTB_TOPO_PRI) {
+			ndev->self_spad = 0;
+			ndev->peer_spad = 0x20;
+		} else {
+			ndev->self_spad = 0x20;
+			ndev->peer_spad = 0;
+		}
+
+		INIT_DELAYED_WORK(&ndev->hb_timer, amd_link_hb);
+		schedule_delayed_work(&ndev->hb_timer, AMD_LINK_HB_TIMEOUT);
+
+		break;
+	default:
+		dev_err(ndev_dev(ndev), "AMD NTB does not support B2B mode.\n");
+		return -EINVAL;
+	}
+
+	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
+
+	/* Mask event interrupts */
+	writel(ndev->int_mask, mmio + AMD_INTMASK_OFFSET);
+
+	return 0;
+}
+
+static enum ntb_topo amd_get_topo(struct amd_ntb_dev *ndev)
+{
+	void __iomem *mmio = ndev->self_mmio;
+	u32 info;
+
+	info = readl(mmio + AMD_SIDEINFO_OFFSET);
+	if (info & AMD_SIDE_MASK)
+		return NTB_TOPO_SEC;
+	else
+		return NTB_TOPO_PRI;
+}
+
+static int amd_init_dev(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev;
+	int rc = 0;
+
+	pdev = ndev_pdev(ndev);
+
+	ndev->ntb.topo = amd_get_topo(ndev);
+	dev_dbg(ndev_dev(ndev), "AMD NTB topo is %s\n",
+		ntb_topo_string(ndev->ntb.topo));
+
+	rc = amd_init_ntb(ndev);
+	if (rc)
+		return rc;
+
+	rc = amd_init_isr(ndev);
+	if (rc) {
+		dev_err(ndev_dev(ndev), "fail to init isr.\n");
+		return rc;
+	}
+
+	ndev->db_valid_mask = BIT_ULL(ndev->db_count) - 1;
+
+	return 0;
+}
+
+static void amd_deinit_dev(struct amd_ntb_dev *ndev)
+{
+	cancel_delayed_work_sync(&ndev->hb_timer);
+
+	ndev_deinit_isr(ndev);
+}
+
+static int amd_ntb_init_pci(struct amd_ntb_dev *ndev,
+			    struct pci_dev *pdev)
+{
+	int rc;
+
+	pci_set_drvdata(pdev, ndev);
+
+	rc = pci_enable_device(pdev);
+	if (rc)
+		goto err_pci_enable;
+
+	rc = pci_request_regions(pdev, NTB_NAME);
+	if (rc)
+		goto err_pci_regions;
+
+	pci_set_master(pdev);
+
+	rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err_dma_mask;
+		dev_warn(ndev_dev(ndev), "Cannot DMA highmem\n");
+	}
+
+	rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(64));
+	if (rc) {
+		rc = pci_set_consistent_dma_mask(pdev, DMA_BIT_MASK(32));
+		if (rc)
+			goto err_dma_mask;
+		dev_warn(ndev_dev(ndev), "Cannot DMA consistent highmem\n");
+	}
+
+	ndev->self_mmio = pci_iomap(pdev, 0, 0);
+	if (!ndev->self_mmio) {
+		rc = -EIO;
+		goto err_dma_mask;
+	}
+	ndev->peer_mmio = ndev->self_mmio + AMD_PEER_OFFSET;
+
+	return 0;
+
+err_dma_mask:
+	pci_clear_master(pdev);
+err_pci_regions:
+	pci_disable_device(pdev);
+err_pci_enable:
+	pci_set_drvdata(pdev, NULL);
+	return rc;
+}
+
+static void amd_ntb_deinit_pci(struct amd_ntb_dev *ndev)
+{
+	struct pci_dev *pdev = ndev_pdev(ndev);
+
+	pci_iounmap(pdev, ndev->self_mmio);
+
+	pci_clear_master(pdev);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	pci_set_drvdata(pdev, NULL);
+}
+
+static int amd_ntb_pci_probe(struct pci_dev *pdev,
+			     const struct pci_device_id *id)
+{
+	struct amd_ntb_dev *ndev;
+	int rc, node;
+
+	node = dev_to_node(&pdev->dev);
+
+	ndev = kzalloc_node(sizeof(*ndev), GFP_KERNEL, node);
+	if (!ndev) {
+		rc = -ENOMEM;
+		goto err_ndev;
+	}
+
+	ndev_init_struct(ndev, pdev);
+
+	rc = amd_ntb_init_pci(ndev, pdev);
+	if (rc)
+		goto err_init_pci;
+
+	rc = amd_init_dev(ndev);
+	if (rc)
+		goto err_init_dev;
+
+	/* write side info */
+	amd_init_side_info(ndev);
+
+	amd_poll_link(ndev);
+
+	ndev_init_debugfs(ndev);
+
+	rc = ntb_register_device(&ndev->ntb);
+	if (rc)
+		goto err_register;
+
+	dev_info(&pdev->dev, "NTB device registered.\n");
+
+	return 0;
+
+err_register:
+	ndev_deinit_debugfs(ndev);
+	amd_deinit_dev(ndev);
+err_init_dev:
+	amd_ntb_deinit_pci(ndev);
+err_init_pci:
+	kfree(ndev);
+err_ndev:
+	return rc;
+}
+
+static void amd_ntb_pci_remove(struct pci_dev *pdev)
+{
+	struct amd_ntb_dev *ndev = pci_get_drvdata(pdev);
+
+	ntb_unregister_device(&ndev->ntb);
+	ndev_deinit_debugfs(ndev);
+	amd_deinit_side_info(ndev);
+	amd_deinit_dev(ndev);
+	amd_ntb_deinit_pci(ndev);
+	kfree(ndev);
+}
+
+static const struct file_operations amd_ntb_debugfs_info = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = ndev_debugfs_read,
+};
+
+static const struct pci_device_id amd_ntb_pci_tbl[] = {
+	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_NTB)},
+	{0}
+};
+MODULE_DEVICE_TABLE(pci, amd_ntb_pci_tbl);
+
+static struct pci_driver amd_ntb_pci_driver = {
+	.name		= KBUILD_MODNAME,
+	.id_table	= amd_ntb_pci_tbl,
+	.probe		= amd_ntb_pci_probe,
+	.remove		= amd_ntb_pci_remove,
+};
+
+static int __init amd_ntb_pci_driver_init(void)
+{
+	pr_info("%s %s\n", NTB_DESC, NTB_VER);
+
+	if (debugfs_initialized())
+		debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
+
+	return pci_register_driver(&amd_ntb_pci_driver);
+}
+module_init(amd_ntb_pci_driver_init);
+
+static void __exit amd_ntb_pci_driver_exit(void)
+{
+	pci_unregister_driver(&amd_ntb_pci_driver);
+	debugfs_remove_recursive(debugfs_dir);
+}
+module_exit(amd_ntb_pci_driver_exit);
diff --git a/drivers/ntb/hw/amd/ntb_hw_amd.h b/drivers/ntb/hw/amd/ntb_hw_amd.h
new file mode 100644
index 0000000..2eac3cd
--- /dev/null
+++ b/drivers/ntb/hw/amd/ntb_hw_amd.h
@@ -0,0 +1,217 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ *   redistributing this file, you may do so under either license.
+ *
+ *   GPL LICENSE SUMMARY
+ *
+ *   Copyright (C) 2016 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of version 2 of the GNU General Public License as
+ *   published by the Free Software Foundation.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright (C) 2016 Advanced Micro Devices, Inc. All Rights Reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copy
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of AMD Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * AMD PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Xiangliang Yu <Xiangliang.Yu@amd.com>
+ */
+
+#ifndef NTB_HW_AMD_H
+#define NTB_HW_AMD_H
+
+#include <linux/ntb.h>
+#include <linux/pci.h>
+
+#define PCI_DEVICE_ID_AMD_NTB	0x145B
+#define AMD_LINK_HB_TIMEOUT	msecs_to_jiffies(1000)
+#define AMD_LINK_STATUS_OFFSET	0x68
+#define NTB_LIN_STA_ACTIVE_BIT	0x00000002
+#define NTB_LNK_STA_SPEED_MASK	0x000F0000
+#define NTB_LNK_STA_WIDTH_MASK	0x03F00000
+#define NTB_LNK_STA_ACTIVE(x)	(!!((x) & NTB_LIN_STA_ACTIVE_BIT))
+#define NTB_LNK_STA_SPEED(x)	(((x) & NTB_LNK_STA_SPEED_MASK) >> 16)
+#define NTB_LNK_STA_WIDTH(x)	(((x) & NTB_LNK_STA_WIDTH_MASK) >> 20)
+
+#ifndef read64
+#ifdef readq
+#define read64 readq
+#else
+#define read64 _read64
+static inline u64 _read64(void __iomem *mmio)
+{
+	u64 low, high;
+
+	low = readl(mmio);
+	high = readl(mmio + sizeof(u32));
+	return low | (high << 32);
+}
+#endif
+#endif
+
+#ifndef write64
+#ifdef writeq
+#define write64 writeq
+#else
+#define write64 _write64
+static inline void _write64(u64 val, void __iomem *mmio)
+{
+	writel(val, mmio);
+	writel(val >> 32, mmio + sizeof(u32));
+}
+#endif
+#endif
+
+enum {
+	/* AMD NTB Capability */
+	AMD_MW_CNT		= 3,
+	AMD_DB_CNT		= 16,
+	AMD_MSIX_VECTOR_CNT	= 24,
+	AMD_SPADS_CNT		= 16,
+
+	/*  AMD NTB register offset */
+	AMD_CNTL_OFFSET		= 0x200,
+
+	/* NTB control register bits */
+	PMM_REG_CTL		= BIT(21),
+	SMM_REG_CTL		= BIT(20),
+	SMM_REG_ACC_PATH	= BIT(18),
+	PMM_REG_ACC_PATH	= BIT(17),
+	NTB_CLK_EN		= BIT(16),
+
+	AMD_STA_OFFSET		= 0x204,
+	AMD_PGSLV_OFFSET	= 0x208,
+	AMD_SPAD_MUX_OFFSET	= 0x20C,
+	AMD_SPAD_OFFSET		= 0x210,
+	AMD_RSMU_HCID		= 0x250,
+	AMD_RSMU_SIID		= 0x254,
+	AMD_PSION_OFFSET	= 0x300,
+	AMD_SSION_OFFSET	= 0x330,
+	AMD_MMINDEX_OFFSET	= 0x400,
+	AMD_MMDATA_OFFSET	= 0x404,
+	AMD_SIDEINFO_OFFSET	= 0x408,
+
+	AMD_SIDE_MASK		= BIT(0),
+	AMD_SIDE_READY		= BIT(1),
+
+	/* limit register */
+	AMD_ROMBARLMT_OFFSET	= 0x410,
+	AMD_BAR1LMT_OFFSET	= 0x414,
+	AMD_BAR23LMT_OFFSET	= 0x418,
+	AMD_BAR45LMT_OFFSET	= 0x420,
+	/* xlat address */
+	AMD_POMBARXLAT_OFFSET	= 0x428,
+	AMD_BAR1XLAT_OFFSET	= 0x430,
+	AMD_BAR23XLAT_OFFSET	= 0x438,
+	AMD_BAR45XLAT_OFFSET	= 0x440,
+	/* doorbell and interrupt */
+	AMD_DBFM_OFFSET		= 0x450,
+	AMD_DBREQ_OFFSET	= 0x454,
+	AMD_MIRRDBSTAT_OFFSET	= 0x458,
+	AMD_DBMASK_OFFSET	= 0x45C,
+	AMD_DBSTAT_OFFSET	= 0x460,
+	AMD_INTMASK_OFFSET	= 0x470,
+	AMD_INTSTAT_OFFSET	= 0x474,
+
+	/* event type */
+	AMD_PEER_FLUSH_EVENT	= BIT(0),
+	AMD_PEER_RESET_EVENT	= BIT(1),
+	AMD_PEER_D3_EVENT	= BIT(2),
+	AMD_PEER_PMETO_EVENT	= BIT(3),
+	AMD_PEER_D0_EVENT	= BIT(4),
+	AMD_EVENT_INTMASK	= (AMD_PEER_FLUSH_EVENT |
+				AMD_PEER_RESET_EVENT | AMD_PEER_D3_EVENT |
+				AMD_PEER_PMETO_EVENT | AMD_PEER_D0_EVENT),
+
+	AMD_PMESTAT_OFFSET	= 0x480,
+	AMD_PMSGTRIG_OFFSET	= 0x490,
+	AMD_LTRLATENCY_OFFSET	= 0x494,
+	AMD_FLUSHTRIG_OFFSET	= 0x498,
+
+	/* SMU register*/
+	AMD_SMUACK_OFFSET	= 0x4A0,
+	AMD_SINRST_OFFSET	= 0x4A4,
+	AMD_RSPNUM_OFFSET	= 0x4A8,
+	AMD_SMU_SPADMUTEX	= 0x4B0,
+	AMD_SMU_SPADOFFSET	= 0x4B4,
+
+	AMD_PEER_OFFSET		= 0x400,
+};
+
+struct amd_ntb_dev;
+
+struct amd_ntb_vec {
+	struct amd_ntb_dev	*ndev;
+	int			num;
+};
+
+struct amd_ntb_dev {
+	struct ntb_dev ntb;
+
+	u32 ntb_side;
+	u32 lnk_sta;
+	u32 cntl_sta;
+	u32 peer_sta;
+
+	unsigned char mw_count;
+	unsigned char spad_count;
+	unsigned char db_count;
+	unsigned char msix_vec_count;
+
+	u64 db_valid_mask;
+	u64 db_mask;
+	u32 int_mask;
+
+	struct msix_entry *msix;
+	struct amd_ntb_vec *vec;
+
+	/* synchronize rmw access of db_mask and hw reg */
+	spinlock_t db_mask_lock;
+
+	void __iomem *self_mmio;
+	void __iomem *peer_mmio;
+	unsigned int self_spad;
+	unsigned int peer_spad;
+
+	struct delayed_work hb_timer;
+
+	struct dentry *debugfs_dir;
+	struct dentry *debugfs_info;
+};
+
+#define ndev_pdev(ndev) ((ndev)->ntb.pdev)
+#define ndev_name(ndev) pci_name(ndev_pdev(ndev))
+#define ndev_dev(ndev) (&ndev_pdev(ndev)->dev)
+#define ntb_ndev(__ntb) container_of(__ntb, struct amd_ntb_dev, ntb)
+#define hb_ndev(__work) container_of(__work, struct amd_ntb_dev, hb_timer.work)
+
+#endif
-- 
1.9.1