Merge branch 'for-3.3/drivers' of git://git.kernel.dk/linux-block

* 'for-3.3/drivers' of git://git.kernel.dk/linux-block:
  mtip32xx: do rebuild monitoring asynchronously
  xen-blkfront: Use kcalloc instead of kzalloc to allocate array
  mtip32xx: uninitialized variable in mtip_quiesce_io()
  mtip32xx: updates based on feedback
  xen-blkback: convert hole punching to discard request on loop devices
  xen/blkback: Move processing of BLKIF_OP_DISCARD from dispatch_rw_block_io
  xen/blk[front|back]: Enhance discard support with secure erasing support.
  xen/blk[front|back]: Squash blkif_request_rw and blkif_request_discard together
  mtip32xx: update to new ->make_request() API
  mtip32xx: add module.h include to avoid conflict with moduleh tree
  mtip32xx: mark a few more items static
  mtip32xx: ensure that all local functions are static
  mtip32xx: cleanup compat ioctl handling
  mtip32xx: fix warnings/errors on 32-bit compiles
  block: Add driver for Micron RealSSD pcie flash cards

11 files changed, 4261 insertions, 112 deletions

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 6f07ec1c2f5..a30aa103f95 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -116,6 +116,8 @@ config PARIDE
 
 source "drivers/block/paride/Kconfig"
 
+source "drivers/block/mtip32xx/Kconfig"
+
 config BLK_CPQ_DA
 	tristate "Compaq SMART2 support"
 	depends on PCI && VIRT_TO_BUS
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 76646e9a1c9..ad7b74a44ef 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -39,5 +39,6 @@ obj-$(CONFIG_XEN_BLKDEV_FRONTEND)	+= xen-blkfront.o
 obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= xen-blkback/
 obj-$(CONFIG_BLK_DEV_DRBD)     += drbd/
 obj-$(CONFIG_BLK_DEV_RBD)     += rbd.o
+obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX)	+= mtip32xx/
 
 swim_mod-y	:= swim.o swim_asm.o
diff --git a/drivers/block/mtip32xx/Kconfig b/drivers/block/mtip32xx/Kconfig
new file mode 100644
index 00000000000..b5dd14e072f
--- /dev/null
+++ b/drivers/block/mtip32xx/Kconfig
@@ -0,0 +1,9 @@
+#
+# mtip32xx device driver configuration
+#
+
+config BLK_DEV_PCIESSD_MTIP32XX
+	tristate "Block Device Driver for Micron PCIe SSDs"
+	depends on HOTPLUG_PCI_PCIE
+	help
+          This enables the block driver for Micron PCIe SSDs.
diff --git a/drivers/block/mtip32xx/Makefile b/drivers/block/mtip32xx/Makefile
new file mode 100644
index 00000000000..4fbef8c8329
--- /dev/null
+++ b/drivers/block/mtip32xx/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for  Block device driver for Micron PCIe SSD
+#
+
+obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX) += mtip32xx.o
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
new file mode 100644
index 00000000000..b74eab70c3d
--- /dev/null
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -0,0 +1,3651 @@
+/*
+ * Driver for the Micron P320 SSD
+ *   Copyright (C) 2011 Micron Technology, Inc.
+ *
+ * Portions of this code were derived from works subjected to the
+ * following copyright:
+ *    Copyright (C) 2009 Integrated Device Technology, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/ata.h>
+#include <linux/delay.h>
+#include <linux/hdreg.h>
+#include <linux/uaccess.h>
+#include <linux/random.h>
+#include <linux/smp.h>
+#include <linux/compat.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/genhd.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/dma-mapping.h>
+#include <linux/idr.h>
+#include <linux/kthread.h>
+#include <../drivers/ata/ahci.h>
+#include "mtip32xx.h"
+
+#define HW_CMD_SLOT_SZ		(MTIP_MAX_COMMAND_SLOTS * 32)
+#define HW_CMD_TBL_SZ		(AHCI_CMD_TBL_HDR_SZ + (MTIP_MAX_SG * 16))
+#define HW_CMD_TBL_AR_SZ	(HW_CMD_TBL_SZ * MTIP_MAX_COMMAND_SLOTS)
+#define HW_PORT_PRIV_DMA_SZ \
+		(HW_CMD_SLOT_SZ + HW_CMD_TBL_AR_SZ + AHCI_RX_FIS_SZ)
+
+#define HOST_HSORG		0xFC
+#define HSORG_DISABLE_SLOTGRP_INTR (1<<24)
+#define HSORG_DISABLE_SLOTGRP_PXIS (1<<16)
+#define HSORG_HWREV		0xFF00
+#define HSORG_STYLE		0x8
+#define HSORG_SLOTGROUPS	0x7
+
+#define PORT_COMMAND_ISSUE	0x38
+#define PORT_SDBV		0x7C
+
+#define PORT_OFFSET		0x100
+#define PORT_MEM_SIZE		0x80
+
+#define PORT_IRQ_ERR \
+	(PORT_IRQ_HBUS_ERR | PORT_IRQ_IF_ERR | PORT_IRQ_CONNECT | \
+	 PORT_IRQ_PHYRDY | PORT_IRQ_UNK_FIS | PORT_IRQ_BAD_PMP | \
+	 PORT_IRQ_TF_ERR | PORT_IRQ_HBUS_DATA_ERR | PORT_IRQ_IF_NONFATAL | \
+	 PORT_IRQ_OVERFLOW)
+#define PORT_IRQ_LEGACY \
+	(PORT_IRQ_PIOS_FIS | PORT_IRQ_D2H_REG_FIS)
+#define PORT_IRQ_HANDLED \
+	(PORT_IRQ_SDB_FIS | PORT_IRQ_LEGACY | \
+	 PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR | \
+	 PORT_IRQ_CONNECT | PORT_IRQ_PHYRDY)
+#define DEF_PORT_IRQ \
+	(PORT_IRQ_ERR | PORT_IRQ_LEGACY | PORT_IRQ_SDB_FIS)
+
+/* product numbers */
+#define MTIP_PRODUCT_UNKNOWN	0x00
+#define MTIP_PRODUCT_ASICFPGA	0x11
+
+/* Device instance number, incremented each time a device is probed. */
+static int instance;
+
+/*
+ * Global variable used to hold the major block device number
+ * allocated in mtip_init().
+ */
+static int mtip_major;
+
+static DEFINE_SPINLOCK(rssd_index_lock);
+static DEFINE_IDA(rssd_index_ida);
+
+static int mtip_block_initialize(struct driver_data *dd);
+
+#ifdef CONFIG_COMPAT
+struct mtip_compat_ide_task_request_s {
+	__u8		io_ports[8];
+	__u8		hob_ports[8];
+	ide_reg_valid_t	out_flags;
+	ide_reg_valid_t	in_flags;
+	int		data_phase;
+	int		req_cmd;
+	compat_ulong_t	out_size;
+	compat_ulong_t	in_size;
+};
+#endif
+
+/*
+ * This function check_for_surprise_removal is called
+ * while card is removed from the system and it will
+ * read the vendor id from the configration space
+ *
+ * @pdev Pointer to the pci_dev structure.
+ *
+ * return value
+ *	 true if device removed, else false
+ */
+static bool mtip_check_surprise_removal(struct pci_dev *pdev)
+{
+	u16 vendor_id = 0;
+
+       /* Read the vendorID from the configuration space */
+	pci_read_config_word(pdev, 0x00, &vendor_id);
+	if (vendor_id == 0xFFFF)
+		return true; /* device removed */
+
+	return false; /* device present */
+}
+
+/*
+ * This function is called for clean the pending command in the
+ * command slot during the surprise removal of device and return
+ * error to the upper layer.
+ *
+ * @dd Pointer to the DRIVER_DATA structure.
+ *
+ * return value
+ *	None
+ */
+static void mtip_command_cleanup(struct driver_data *dd)
+{
+	int group = 0, commandslot = 0, commandindex = 0;
+	struct mtip_cmd *command;
+	struct mtip_port *port = dd->port;
+
+	for (group = 0; group < 4; group++) {
+		for (commandslot = 0; commandslot < 32; commandslot++) {
+			if (!(port->allocated[group] & (1 << commandslot)))
+				continue;
+
+			commandindex = group << 5 | commandslot;
+			command = &port->commands[commandindex];
+
+			if (atomic_read(&command->active)
+			    && (command->async_callback)) {
+				command->async_callback(command->async_data,
+					-ENODEV);
+				command->async_callback = NULL;
+				command->async_data = NULL;
+			}
+
+			dma_unmap_sg(&port->dd->pdev->dev,
+				command->sg,
+				command->scatter_ents,
+				command->direction);
+		}
+	}
+
+	up(&port->cmd_slot);
+
+	atomic_set(&dd->drv_cleanup_done, true);
+}
+
+/*
+ * Obtain an empty command slot.
+ *
+ * This function needs to be reentrant since it could be called
+ * at the same time on multiple CPUs. The allocation of the
+ * command slot must be atomic.
+ *
+ * @port Pointer to the port data structure.
+ *
+ * return value
+ *	>= 0	Index of command slot obtained.
+ *	-1	No command slots available.
+ */
+static int get_slot(struct mtip_port *port)
+{
+	int slot, i;
+	unsigned int num_command_slots = port->dd->slot_groups * 32;
+
+	/*
+	 * Try 10 times, because there is a small race here.
+	 *  that's ok, because it's still cheaper than a lock.
+	 *
+	 * Race: Since this section is not protected by lock, same bit
+	 * could be chosen by different process contexts running in
+	 * different processor. So instead of costly lock, we are going
+	 * with loop.
+	 */
+	for (i = 0; i < 10; i++) {
+		slot = find_next_zero_bit(port->allocated,
+					 num_command_slots, 1);
+		if ((slot < num_command_slots) &&
+		    (!test_and_set_bit(slot, port->allocated)))
+			return slot;
+	}
+	dev_warn(&port->dd->pdev->dev, "Failed to get a tag.\n");
+
+	if (mtip_check_surprise_removal(port->dd->pdev)) {
+		/* Device not present, clean outstanding commands */
+		mtip_command_cleanup(port->dd);
+	}
+	return -1;
+}
+
+/*
+ * Release a command slot.
+ *
+ * @port Pointer to the port data structure.
+ * @tag  Tag of command to release
+ *
+ * return value
+ *	None
+ */
+static inline void release_slot(struct mtip_port *port, int tag)
+{
+	smp_mb__before_clear_bit();
+	clear_bit(tag, port->allocated);
+	smp_mb__after_clear_bit();
+}
+
+/*
+ * Reset the HBA (without sleeping)
+ *
+ * Just like hba_reset, except does not call sleep, so can be
+ * run from interrupt/tasklet context.
+ *
+ * @dd Pointer to the driver data structure.
+ *
+ * return value
+ *	0	The reset was successful.
+ *	-1	The HBA Reset bit did not clear.
+ */
+static int hba_reset_nosleep(struct driver_data *dd)
+{
+	unsigned long timeout;
+
+	/* Chip quirk: quiesce any chip function */
+	mdelay(10);
+
+	/* Set the reset bit */
+	writel(HOST_RESET, dd->mmio + HOST_CTL);
+
+	/* Flush */
+	readl(dd->mmio + HOST_CTL);
+
+	/*
+	 * Wait 10ms then spin for up to 1 second
+	 * waiting for reset acknowledgement
+	 */
+	timeout = jiffies + msecs_to_jiffies(1000);
+	mdelay(10);
+	while ((readl(dd->mmio + HOST_CTL) & HOST_RESET)
+		 && time_before(jiffies, timeout))
+		mdelay(1);
+
+	if (readl(dd->mmio + HOST_CTL) & HOST_RESET)
+		return -1;
+
+	return 0;
+}
+
+/*
+ * Issue a command to the hardware.
+ *
+ * Set the appropriate bit in the s_active and Command Issue hardware
+ * registers, causing hardware command processing to begin.
+ *
+ * @port Pointer to the port structure.
+ * @tag  The tag of the command to be issued.
+ *
+ * return value
+ *      None
+ */
+static inline void mtip_issue_ncq_command(struct mtip_port *port, int tag)
+{
+	unsigned long flags = 0;
+
+	atomic_set(&port->commands[tag].active, 1);
+
+	spin_lock_irqsave(&port->cmd_issue_lock, flags);
+
+	writel((1 << MTIP_TAG_BIT(tag)),
+			port->s_active[MTIP_TAG_INDEX(tag)]);
+	writel((1 << MTIP_TAG_BIT(tag)),
+			port->cmd_issue[MTIP_TAG_INDEX(tag)]);
+
+	spin_unlock_irqrestore(&port->cmd_issue_lock, flags);
+}
+
+/*
+ * Enable/disable the reception of FIS
+ *
+ * @port   Pointer to the port data structure
+ * @enable 1 to enable, 0 to disable
+ *
+ * return value
+ *	Previous state: 1 enabled, 0 disabled
+ */
+static int mtip_enable_fis(struct mtip_port *port, int enable)
+{
+	u32 tmp;
+
+	/* enable FIS reception */
+	tmp = readl(port->mmio + PORT_CMD);
+	if (enable)
+		writel(tmp | PORT_CMD_FIS_RX, port->mmio + PORT_CMD);
+	else
+		writel(tmp & ~PORT_CMD_FIS_RX, port->mmio + PORT_CMD);
+
+	/* Flush */
+	readl(port->mmio + PORT_CMD);
+
+	return (((tmp & PORT_CMD_FIS_RX) == PORT_CMD_FIS_RX));
+}
+
+/*
+ * Enable/disable the DMA engine
+ *
+ * @port   Pointer to the port data structure
+ * @enable 1 to enable, 0 to disable
+ *
+ * return value
+ *	Previous state: 1 enabled, 0 disabled.
+ */
+static int mtip_enable_engine(struct mtip_port *port, int enable)
+{
+	u32 tmp;
+
+	/* enable FIS reception */
+	tmp = readl(port->mmio + PORT_CMD);
+	if (enable)
+		writel(tmp | PORT_CMD_START, port->mmio + PORT_CMD);
+	else
+		writel(tmp & ~PORT_CMD_START, port->mmio + PORT_CMD);
+
+	readl(port->mmio + PORT_CMD);
+	return (((tmp & PORT_CMD_START) == PORT_CMD_START));
+}
+
+/*
+ * Enables the port DMA engine and FIS reception.
+ *
+ * return value
+ *	None
+ */
+static inline void mtip_start_port(struct mtip_port *port)
+{
+	/* Enable FIS reception */
+	mtip_enable_fis(port, 1);
+
+	/* Enable the DMA engine */
+	mtip_enable_engine(port, 1);
+}
+
+/*
+ * Deinitialize a port by disabling port interrupts, the DMA engine,
+ * and FIS reception.
+ *
+ * @port Pointer to the port structure
+ *
+ * return value
+ *	None
+ */
+static inline void mtip_deinit_port(struct mtip_port *port)
+{
+	/* Disable interrupts on this port */
+	writel(0, port->mmio + PORT_IRQ_MASK);
+
+	/* Disable the DMA engine */
+	mtip_enable_engine(port, 0);
+
+	/* Disable FIS reception */
+	mtip_enable_fis(port, 0);
+}
+
+/*
+ * Initialize a port.
+ *
+ * This function deinitializes the port by calling mtip_deinit_port() and
+ * then initializes it by setting the command header and RX FIS addresses,
+ * clearing the SError register and any pending port interrupts before
+ * re-enabling the default set of port interrupts.
+ *
+ * @port Pointer to the port structure.
+ *
+ * return value
+ *	None
+ */
+static void mtip_init_port(struct mtip_port *port)
+{
+	int i;
+	mtip_deinit_port(port);
+
+	/* Program the command list base and FIS base addresses */
+	if (readl(port->dd->mmio + HOST_CAP) & HOST_CAP_64) {
+		writel((port->command_list_dma >> 16) >> 16,
+			 port->mmio + PORT_LST_ADDR_HI);
+		writel((port->rxfis_dma >> 16) >> 16,
+			 port->mmio + PORT_FIS_ADDR_HI);
+	}
+
+	writel(port->command_list_dma & 0xFFFFFFFF,
+			port->mmio + PORT_LST_ADDR);
+	writel(port->rxfis_dma & 0xFFFFFFFF, port->mmio + PORT_FIS_ADDR);
+
+	/* Clear SError */
+	writel(readl(port->mmio + PORT_SCR_ERR), port->mmio + PORT_SCR_ERR);
+
+	/* reset the completed registers.*/
+	for (i = 0; i < port->dd->slot_groups; i++)
+		writel(0xFFFFFFFF, port->completed[i]);
+
+	/* Clear any pending interrupts for this port */
+	writel(readl(port->mmio + PORT_IRQ_STAT), port->mmio + PORT_IRQ_STAT);
+
+	/* Enable port interrupts */
+	writel(DEF_PORT_IRQ, port->mmio + PORT_IRQ_MASK);
+}
+
+/*
+ * Restart a port
+ *
+ * @port Pointer to the port data structure.
+ *
+ * return value
+ *	None
+ */
+static void mtip_restart_port(struct mtip_port *port)
+{
+	unsigned long timeout;
+
+	/* Disable the DMA engine */
+	mtip_enable_engine(port, 0);
+
+	/* Chip quirk: wait up to 500ms for PxCMD.CR == 0 */
+	timeout = jiffies + msecs_to_jiffies(500);
+	while ((readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON)
+		 && time_before(jiffies, timeout))
+		;
+
+	/*
+	 * Chip quirk: escalate to hba reset if
+	 * PxCMD.CR not clear after 500 ms
+	 */
+	if (readl(port->mmio + PORT_CMD) & PORT_CMD_LIST_ON) {
+		dev_warn(&port->dd->pdev->dev,
+			"PxCMD.CR not clear, escalating reset\n");
+
+		if (hba_reset_nosleep(port->dd))
+			dev_err(&port->dd->pdev->dev,
+				"HBA reset escalation failed.\n");
+
+		/* 30 ms delay before com reset to quiesce chip */
+		mdelay(30);
+	}
+
+	dev_warn(&port->dd->pdev->dev, "Issuing COM reset\n");
+
+	/* Set PxSCTL.DET */
+	writel(readl(port->mmio + PORT_SCR_CTL) |
+			 1, port->mmio + PORT_SCR_CTL);
+	readl(port->mmio + PORT_SCR_CTL);
+
+	/* Wait 1 ms to quiesce chip function */
+	timeout = jiffies + msecs_to_jiffies(1);
+	while (time_before(jiffies, timeout))
+		;
+
+	/* Clear PxSCTL.DET */
+	writel(readl(port->mmio + PORT_SCR_CTL) & ~1,
+			 port->mmio + PORT_SCR_CTL);
+	readl(port->mmio + PORT_SCR_CTL);
+
+	/* Wait 500 ms for bit 0 of PORT_SCR_STS to be set */
+	timeout = jiffies + msecs_to_jiffies(500);
+	while (((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
+			 && time_before(jiffies, timeout))
+		;
+
+	if ((readl(port->mmio + PORT_SCR_STAT) & 0x01) == 0)
+		dev_warn(&port->dd->pdev->dev,
+			"COM reset failed\n");
+
+	/* Clear SError, the PxSERR.DIAG.x should be set so clear it */
+	writel(readl(port->mmio + PORT_SCR_ERR), port->mmio + PORT_SCR_ERR);
+
+	/* Enable the DMA engine */
+	mtip_enable_engine(port, 1);
+}
+
+/*
+ * Called periodically to see if any read/write commands are
+ * taking too long to complete.
+ *
+ * @data Pointer to the PORT data structure.
+ *
+ * return value
+ *	None
+ */
+static void mtip_timeout_function(unsigned long int data)
+{
+	struct mtip_port *port = (struct mtip_port *) data;
+	struct host_to_dev_fis *fis;
+	struct mtip_cmd *command;
+	int tag, cmdto_cnt = 0;
+	unsigned int bit, group;
+	unsigned int num_command_slots = port->dd->slot_groups * 32;
+
+	if (unlikely(!port))
+		return;
+
+	if (atomic_read(&port->dd->resumeflag) == true) {
+		mod_timer(&port->cmd_timer,
+			jiffies + msecs_to_jiffies(30000));
+		return;
+	}
+
+	for (tag = 0; tag < num_command_slots; tag++) {
+		/*
+		 * Skip internal command slot as it has
+		 * its own timeout mechanism
+		 */
+		if (tag == MTIP_TAG_INTERNAL)
+			continue;
+
+		if (atomic_read(&port->commands[tag].active) &&
+		   (time_after(jiffies, port->commands[tag].comp_time))) {
+			group = tag >> 5;
+			bit = tag & 0x1F;
+
+			command = &port->commands[tag];
+			fis = (struct host_to_dev_fis *) command->command;
+
+			dev_warn(&port->dd->pdev->dev,
+				"Timeout for command tag %d\n", tag);
+
+			cmdto_cnt++;
+			if (cmdto_cnt == 1)
+				set_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
+
+			/*
+			 * Clear the completed bit. This should prevent
+			 *  any interrupt handlers from trying to retire
+			 *  the command.
+			 */
+			writel(1 << bit, port->completed[group]);
+
+			/* Call the async completion callback. */
+			if (likely(command->async_callback))
+				command->async_callback(command->async_data,
+							 -EIO);
+			command->async_callback = NULL;
+			command->comp_func = NULL;
+
+			/* Unmap the DMA scatter list entries */
+			dma_unmap_sg(&port->dd->pdev->dev,
+					command->sg,
+					command->scatter_ents,
+					command->direction);
+
+			/*
+			 * Clear the allocated bit and active tag for the
+			 * command.
+			 */
+			atomic_set(&port->commands[tag].active, 0);
+			release_slot(port, tag);
+
+			up(&port->cmd_slot);
+		}
+	}
+
+	if (cmdto_cnt) {
+		dev_warn(&port->dd->pdev->dev,
+			"%d commands timed out: restarting port",
+			cmdto_cnt);
+		mtip_restart_port(port);
+		clear_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
+		wake_up_interruptible(&port->svc_wait);
+	}
+
+	/* Restart the timer */
+	mod_timer(&port->cmd_timer,
+		jiffies + msecs_to_jiffies(MTIP_TIMEOUT_CHECK_PERIOD));
+}
+
+/*
+ * IO completion function.
+ *
+ * This completion function is called by the driver ISR when a
+ * command that was issued by the kernel completes. It first calls the
+ * asynchronous completion function which normally calls back into the block
+ * layer passing the asynchronous callback data, then unmaps the
+ * scatter list associated with the completed command, and finally
+ * clears the allocated bit associated with the completed command.
+ *
+ * @port   Pointer to the port data structure.
+ * @tag    Tag of the command.
+ * @data   Pointer to driver_data.
+ * @status Completion status.
+ *
+ * return value
+ *	None
+ */
+static void mtip_async_complete(struct mtip_port *port,
+				int tag,
+				void *data,
+				int status)
+{
+	struct mtip_cmd *command;
+	struct driver_data *dd = data;
+	int cb_status = status ? -EIO : 0;
+
+	if (unlikely(!dd) || unlikely(!port))
+		return;
+
+	command = &port->commands[tag];
+
+	if (unlikely(status == PORT_IRQ_TF_ERR)) {
+		dev_warn(&port->dd->pdev->dev,
+			"Command tag %d failed due to TFE\n", tag);
+	}
+
+	/* Upper layer callback */
+	if (likely(command->async_callback))
+		command->async_callback(command->async_data, cb_status);
+
+	command->async_callback = NULL;
+	command->comp_func = NULL;
+
+	/* Unmap the DMA scatter list entries */
+	dma_unmap_sg(&dd->pdev->dev,
+		command->sg,
+		command->scatter_ents,
+		command->direction);
+
+	/* Clear the allocated and active bits for the command */
+	atomic_set(&port->commands[tag].active, 0);
+	release_slot(port, tag);
+
+	up(&port->cmd_slot);
+}
+
+/*
+ * Internal command completion callback function.
+ *
+ * This function is normally called by the driver ISR when an internal
+ * command completed. This function signals the command completion by
+ * calling complete().
+ *
+ * @port   Pointer to the port data structure.
+ * @tag    Tag of the command that has completed.
+ * @data   Pointer to a completion structure.
+ * @status Completion status.
+ *
+ * return value
+ *	None
+ */
+static void mtip_completion(struct mtip_port *port,
+			    int tag,
+			    void *data,
+			    int status)
+{
+	struct mtip_cmd *command = &port->commands[tag];
+	struct completion *waiting = data;
+	if (unlikely(status == PORT_IRQ_TF_ERR))
+		dev_warn(&port->dd->pdev->dev,
+			"Internal command %d completed with TFE\n", tag);
+
+	command->async_callback = NULL;
+	command->comp_func = NULL;
+
+	complete(waiting);
+}
+
+/*
+ * Helper function for tag logging
+ */
+static void print_tags(struct driver_data *dd,
+			char *msg,
+			unsigned long *tagbits)
+{
+	unsigned int tag, count = 0;
+
+	for (tag = 0; tag < (dd->slot_groups) * 32; tag++) {
+		if (test_bit(tag, tagbits))
+			count++;
+	}
+	if (count)
+		dev_info(&dd->pdev->dev, "%s [%i tags]\n", msg, count);
+}
+
+/*
+ * Handle an error.
+ *
+ * @dd Pointer to the DRIVER_DATA structure.
+ *
+ * return value
+ *	None
+ */
+static void mtip_handle_tfe(struct driver_data *dd)
+{
+	int group, tag, bit, reissue;
+	struct mtip_port *port;
+	struct mtip_cmd  *command;
+	u32 completed;
+	struct host_to_dev_fis *fis;
+	unsigned long tagaccum[SLOTBITS_IN_LONGS];
+
+	dev_warn(&dd->pdev->dev, "Taskfile error\n");
+
+	port = dd->port;
+
+	/* Stop the timer to prevent command timeouts. */
+	del_timer(&port->cmd_timer);
+
+	/* Set eh_active */
+	set_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
+
+	/* Loop through all the groups */
+	for (group = 0; group < dd->slot_groups; group++) {
+		completed = readl(port->completed[group]);
+
+		/* clear completed status register in the hardware.*/
+		writel(completed, port->completed[group]);
+
+		/* clear the tag accumulator */
+		memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));
+
+		/* Process successfully completed commands */
+		for (bit = 0; bit < 32 && completed; bit++) {
+			if (!(completed & (1<<bit)))
+				continue;
+			tag = (group << 5) + bit;
+
+			/* Skip the internal command slot */
+			if (tag == MTIP_TAG_INTERNAL)
+				continue;
+
+			command = &port->commands[tag];
+			if (likely(command->comp_func)) {
+				set_bit(tag, tagaccum);
+				atomic_set(&port->commands[tag].active, 0);
+				command->comp_func(port,
+					 tag,
+					 command->comp_data,
+					 0);
+			} else {
+				dev_err(&port->dd->pdev->dev,
+					"Missing completion func for tag %d",
+					tag);
+				if (mtip_check_surprise_removal(dd->pdev)) {
+					mtip_command_cleanup(dd);
+					/* don't proceed further */
+					return;
+				}
+			}
+		}
+	}
+	print_tags(dd, "TFE tags completed:", tagaccum);
+
+	/* Restart the port */
+	mdelay(20);
+	mtip_restart_port(port);
+
+	/* clear the tag accumulator */
+	memset(tagaccum, 0, SLOTBITS_IN_LONGS * sizeof(long));
+
+	/* Loop through all the groups */
+	for (group = 0; group < dd->slot_groups; group++) {
+		for (bit = 0; bit < 32; bit++) {
+			reissue = 1;
+			tag = (group << 5) + bit;
+
+			/* If the active bit is set re-issue the command */
+			if (atomic_read(&port->commands[tag].active) == 0)
+				continue;
+
+			fis = (struct host_to_dev_fis *)
+				port->commands[tag].command;
+
+			/* Should re-issue? */
+			if (tag == MTIP_TAG_INTERNAL ||
+			    fis->command == ATA_CMD_SET_FEATURES)
+				reissue = 0;
+
+			/*
+			 * First check if this command has
+			 *  exceeded its retries.
+			 */
+			if (reissue &&
+			    (port->commands[tag].retries-- > 0)) {
+
+				set_bit(tag, tagaccum);
+
+				/* Update the timeout value. */
+				port->commands[tag].comp_time =
+					jiffies + msecs_to_jiffies(
+					MTIP_NCQ_COMMAND_TIMEOUT_MS);
+				/* Re-issue the command. */
+				mtip_issue_ncq_command(port, tag);
+
+				continue;
+			}
+
+			/* Retire a command that will not be reissued */
+			dev_warn(&port->dd->pdev->dev,
+				"retiring tag %d\n", tag);
+			atomic_set(&port->commands[tag].active, 0);
+
+			if (port->commands[tag].comp_func)
+				port->commands[tag].comp_func(
+					port,
+					tag,
+					port->commands[tag].comp_data,
+					PORT_IRQ_TF_ERR);
+			else
+				dev_warn(&port->dd->pdev->dev,
+					"Bad completion for tag %d\n",
+					tag);
+		}
+	}
+	print_tags(dd, "TFE tags reissued:", tagaccum);
+
+	/* clear eh_active */
+	clear_bit(MTIP_FLAG_EH_ACTIVE_BIT, &port->flags);
+	wake_up_interruptible(&port->svc_wait);
+
+	mod_timer(&port->cmd_timer,
+		 jiffies + msecs_to_jiffies(MTIP_TIMEOUT_CHECK_PERIOD));
+}
+
+/*
+ * Handle a set device bits interrupt
+ */
+static inline void mtip_process_sdbf(struct driver_data *dd)
+{
+	struct mtip_port  *port = dd->port;
+	int group, tag, bit;
+	u32 completed;
+	struct mtip_cmd *command;
+
+	/* walk all bits in all slot groups */
+	for (group = 0; group < dd->slot_groups; group++) {
+		completed = readl(port->completed[group]);
+
+		/* clear completed status register in the hardware.*/
+		writel(completed, port->completed[group]);
+
+		/* Process completed commands. */
+		for (bit = 0;
+		     (bit < 32) && completed;
+		     bit++, completed >>= 1) {
+			if (completed & 0x01) {
+				tag = (group << 5) | bit;
+
+				/* skip internal command slot. */
+				if (unlikely(tag == MTIP_TAG_INTERNAL))
+					continue;
+
+				command = &port->commands[tag];
+				/* make internal callback */
+				if (likely(command->comp_func)) {
+					command->comp_func(
+						port,
+						tag,
+						command->comp_data,
+						0);
+				} else {
+					dev_warn(&dd->pdev->dev,
+						"Null completion "
+						"for tag %d",
+						tag);
+
+					if (mtip_check_surprise_removal(
+						dd->pdev)) {
+						mtip_command_cleanup(dd);
+						return;
+					}
+				}
+			}
+		}
+	}
+}
+
+/*
+ * Process legacy pio and d2h interrupts
+ */
+static inline void mtip_process_legacy(struct driver_data *dd, u32 port_stat)
+{
+	struct mtip_port *port = dd->port;
+	struct mtip_cmd *cmd = &port->commands[MTIP_TAG_INTERNAL];
+
+	if (test_bit(MTIP_FLAG_IC_ACTIVE_BIT, &port->flags) &&
+	    (cmd != NULL) && !(readl(port->cmd_issue[MTIP_TAG_INTERNAL])
+		& (1 << MTIP_TAG_INTERNAL))) {
+		if (cmd->comp_func) {
+			cmd->comp_func(port,
+				MTIP_TAG_INTERNAL,
+				cmd->comp_data,
+				0);
+			return;
+		}
+	}
+
+	dev_warn(&dd->pdev->dev, "IRQ status 0x%x ignored.\n", port_stat);
+
+	return;
+}
+
+/*
+ * Demux and handle errors
+ */
+static inline void mtip_process_errors(struct driver_data *dd, u32 port_stat)
+{
+	if (likely(port_stat & (PORT_IRQ_TF_ERR | PORT_IRQ_IF_ERR)))
+		mtip_handle_tfe(dd);
+
+	if (unlikely(port_stat & PORT_IRQ_CONNECT)) {
+		dev_warn(&dd->pdev->dev,
+			"Clearing PxSERR.DIAG.x\n");
+		writel((1 << 26), dd->port->mmio + PORT_SCR_ERR);
+	}
+
+	if (unlikely(port_stat & PORT_IRQ_PHYRDY)) {
+		dev_warn(&dd->pdev->dev,
+			"Clearing PxSERR.DIAG.n\n");
+		writel((1 << 16), dd->port->mmio + PORT_SCR_ERR);
+	}
+
+	if (unlikely(port_stat & ~PORT_IRQ_HANDLED)) {
+		dev_warn(&dd->pdev->dev,
+			"Port stat errors %x unhandled\n",
+			(port_stat & ~PORT_IRQ_HANDLED));
+	}
+}
+
+static inline irqreturn_t mtip_handle_irq(struct driver_data *data)
+{
+	struct driver_data *dd = (struct driver_data *) data;
+	struct mtip_port *port = dd->port;
+	u32 hba_stat, port_stat;
+	int rv = IRQ_NONE;
+
+	hba_stat = readl(dd->mmio + HOST_IRQ_STAT);
+	if (hba_stat) {
+		rv = IRQ_HANDLED;
+
+		/* Acknowledge the interrupt status on the port.*/
+		port_stat = readl(port->mmio + PORT_IRQ_STAT);
+		writel(port_stat, port->mmio + PORT_IRQ_STAT);
+
+		/* Demux port status */
+		if (likely(port_stat & PORT_IRQ_SDB_FIS))
+			mtip_process_sdbf(dd);
+
+		if (unlikely(port_stat & PORT_IRQ_ERR)) {
+			if (unlikely(mtip_check_surprise_removal(dd->pdev))) {
+				mtip_command_cleanup(dd);
+				/* don't proceed further */
+				return IRQ_HANDLED;
+			}
+
+			mtip_process_errors(dd, port_stat & PORT_IRQ_ERR);
+		}
+
+		if (unlikely(port_stat & PORT_IRQ_LEGACY))
+			mtip_process_legacy(dd, port_stat & PORT_IRQ_LEGACY);
+	}
+
+	/* acknowledge interrupt */
+	writel(hba_stat, dd->mmio + HOST_IRQ_STAT);
+
+	return rv;
+}
+
+/*
+ * Wrapper for mtip_handle_irq
+ * (ignores return code)
+ */
+static void mtip_tasklet(unsigned long data)
+{
+	mtip_handle_irq((struct driver_data *) data);
+}
+
+/*
+ * HBA interrupt subroutine.
+ *
+ * @irq		IRQ number.
+ * @instance	Pointer to the driver data structure.
+ *
+ * return value
+ *	IRQ_HANDLED	A HBA interrupt was pending and handled.
+ *	IRQ_NONE	This interrupt was not for the HBA.
+ */
+static irqreturn_t mtip_irq_handler(int irq, void *instance)
+{
+	struct driver_data *dd = instance;
+	tasklet_schedule(&dd->tasklet);
+	return IRQ_HANDLED;
+}
+
+static void mtip_issue_non_ncq_command(struct mtip_port *port, int tag)
+{
+	atomic_set(&port->commands[tag].active, 1);
+	writel(1 << MTIP_TAG_BIT(tag),
+		port->cmd_issue[MTIP_TAG_INDEX(tag)]);
+}
+
+/*
+ * Wait for port to quiesce
+ *
+ * @port    Pointer to port data structure
+ * @timeout Max duration to wait (ms)
+ *
+ * return value
+ *	0	Success
+ *	-EBUSY  Commands still active
+ */
+static int mtip_quiesce_io(struct mtip_port *port, unsigned long timeout)
+{
+	unsigned long to;