Commit 0d5c10b4 authored by Dave Jiang's avatar Dave Jiang Committed by Vinod Koul
Browse files

dmaengine: idxd: add work queue drain support 



Add wq drain support. When a wq is being released, it needs to wait for
all in-flight operation to complete.  A device control function
idxd_wq_drain() has been added to facilitate this. A wq drain call
is added to the char dev on release to make sure all user operations are
complete. A wq drain is also added before the wq is being disabled.

A drain command can take an unpredictable period of time. Interrupt support
for device commands is added to allow waiting on the command to
finish. If a previous command is in progress, the new submitter can block
until the current command is finished before proceeding. The interrupt
based submission will submit the command and then wait until a command
completion interrupt happens to complete. All commands are moved to the
interrupt based command submission except for the device reset during
probe, which will be polled.

Fixes: 42d279f9 ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/159319502515.69593.13451647706946040301.stgit@djiang5-desk3.ch.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent d12ea559

drivers/dma/idxd/cdev.c

+3 −0
Original line number Diff line number Diff line
@@ -104,6 +104,9 @@ static int idxd_cdev_release(struct inode *node, struct file *filep) 
	dev_dbg(dev, "%s called\n", __func__);

	filep->private_data = NULL;



	/* Wait for in-flight operations to complete. */

	idxd_wq_drain(wq);



	kfree(ctx);

	idxd_wq_put(wq);

	return 0;

drivers/dma/idxd/device.c

+70 −85
Original line number Diff line number Diff line
@@ -11,8 +11,8 @@ 
#include "idxd.h"

#include "registers.h"



static int idxd_cmd_wait(struct idxd_device *idxd, u32 *status, int timeout);

static int idxd_cmd_send(struct idxd_device *idxd, int cmd_code, u32 operand);

static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,

			  u32 *status);



/* Interrupt control bits */

int idxd_mask_msix_vector(struct idxd_device *idxd, int vec_id)
@@ -233,21 +233,13 @@ int idxd_wq_enable(struct idxd_wq *wq) 
	struct idxd_device *idxd = wq->idxd;

	struct device *dev = &idxd->pdev->dev;

	u32 status;

	int rc;



	lockdep_assert_held(&idxd->dev_lock);



	if (wq->state == IDXD_WQ_ENABLED) {

		dev_dbg(dev, "WQ %d already enabled\n", wq->id);

		return -ENXIO;

	}



	rc = idxd_cmd_send(idxd, IDXD_CMD_ENABLE_WQ, wq->id);

	if (rc < 0)

		return rc;

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;

	idxd_cmd_exec(idxd, IDXD_CMD_ENABLE_WQ, wq->id, &status);



	if (status != IDXD_CMDSTS_SUCCESS &&

	    status != IDXD_CMDSTS_ERR_WQ_ENABLED) {
@@ -265,9 +257,7 @@ int idxd_wq_disable(struct idxd_wq *wq) 
	struct idxd_device *idxd = wq->idxd;

	struct device *dev = &idxd->pdev->dev;

	u32 status, operand;

	int rc;



	lockdep_assert_held(&idxd->dev_lock);

	dev_dbg(dev, "Disabling WQ %d\n", wq->id);



	if (wq->state != IDXD_WQ_ENABLED) {
@@ -276,12 +266,7 @@ int idxd_wq_disable(struct idxd_wq *wq) 
	}



	operand = BIT(wq->id % 16) | ((wq->id / 16) << 16);

	rc = idxd_cmd_send(idxd, IDXD_CMD_DISABLE_WQ, operand);

	if (rc < 0)

		return rc;

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;

	idxd_cmd_exec(idxd, IDXD_CMD_DISABLE_WQ, operand, &status);



	if (status != IDXD_CMDSTS_SUCCESS) {

		dev_dbg(dev, "WQ disable failed: %#x\n", status);
@@ -293,6 +278,22 @@ int idxd_wq_disable(struct idxd_wq *wq) 
	return 0;

}



void idxd_wq_drain(struct idxd_wq *wq)

{

	struct idxd_device *idxd = wq->idxd;

	struct device *dev = &idxd->pdev->dev;

	u32 operand;



	if (wq->state != IDXD_WQ_ENABLED) {

		dev_dbg(dev, "WQ %d in wrong state: %d\n", wq->id, wq->state);

		return;

	}



	dev_dbg(dev, "Draining WQ %d\n", wq->id);

	operand = BIT(wq->id % 16) | ((wq->id / 16) << 16);

	idxd_cmd_exec(idxd, IDXD_CMD_DRAIN_WQ, operand, NULL);

}



int idxd_wq_map_portal(struct idxd_wq *wq)

{

	struct idxd_device *idxd = wq->idxd;
@@ -330,66 +331,79 @@ static inline bool idxd_is_enabled(struct idxd_device *idxd) 
	return false;

}



static int idxd_cmd_wait(struct idxd_device *idxd, u32 *status, int timeout)

/*

 * This is function is only used for reset during probe and will

 * poll for completion. Once the device is setup with interrupts,

 * all commands will be done via interrupt completion.

 */

void idxd_device_init_reset(struct idxd_device *idxd)

{

	u32 sts, to = timeout;



	lockdep_assert_held(&idxd->dev_lock);

	sts = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);

	while (sts & IDXD_CMDSTS_ACTIVE && --to) {

		cpu_relax();

		sts = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);

	}

	struct device *dev = &idxd->pdev->dev;

	union idxd_command_reg cmd;

	unsigned long flags;



	if (to == 0 && sts & IDXD_CMDSTS_ACTIVE) {

		dev_warn(&idxd->pdev->dev, "%s timed out!\n", __func__);

		*status = 0;

		return -EBUSY;

	}

	memset(&cmd, 0, sizeof(cmd));

	cmd.cmd = IDXD_CMD_RESET_DEVICE;

	dev_dbg(dev, "%s: sending reset for init.\n", __func__);

	spin_lock_irqsave(&idxd->dev_lock, flags);

	iowrite32(cmd.bits, idxd->reg_base + IDXD_CMD_OFFSET);



	*status = sts;

	return 0;

	while (ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET) &

	       IDXD_CMDSTS_ACTIVE)

		cpu_relax();

	spin_unlock_irqrestore(&idxd->dev_lock, flags);

}



static int idxd_cmd_send(struct idxd_device *idxd, int cmd_code, u32 operand)

static void idxd_cmd_exec(struct idxd_device *idxd, int cmd_code, u32 operand,

			  u32 *status)

{

	union idxd_command_reg cmd;

	int rc;

	u32 status;



	lockdep_assert_held(&idxd->dev_lock);

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;

	DECLARE_COMPLETION_ONSTACK(done);

	unsigned long flags;



	memset(&cmd, 0, sizeof(cmd));

	cmd.cmd = cmd_code;

	cmd.operand = operand;

	cmd.int_req = 1;



	spin_lock_irqsave(&idxd->dev_lock, flags);

	wait_event_lock_irq(idxd->cmd_waitq,

			    !test_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags),

			    idxd->dev_lock);



	dev_dbg(&idxd->pdev->dev, "%s: sending cmd: %#x op: %#x\n",

		__func__, cmd_code, operand);



	__set_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags);

	idxd->cmd_done = &done;

	iowrite32(cmd.bits, idxd->reg_base + IDXD_CMD_OFFSET);



	return 0;

	/*

	 * After command submitted, release lock and go to sleep until

	 * the command completes via interrupt.

	 */

	spin_unlock_irqrestore(&idxd->dev_lock, flags);

	wait_for_completion(&done);

	spin_lock_irqsave(&idxd->dev_lock, flags);

	if (status)

		*status = ioread32(idxd->reg_base + IDXD_CMDSTS_OFFSET);

	__clear_bit(IDXD_FLAG_CMD_RUNNING, &idxd->flags);

	/* Wake up other pending commands */

	wake_up(&idxd->cmd_waitq);

	spin_unlock_irqrestore(&idxd->dev_lock, flags);

}



int idxd_device_enable(struct idxd_device *idxd)

{

	struct device *dev = &idxd->pdev->dev;

	int rc;

	u32 status;



	lockdep_assert_held(&idxd->dev_lock);

	if (idxd_is_enabled(idxd)) {

		dev_dbg(dev, "Device already enabled\n");

		return -ENXIO;

	}



	rc = idxd_cmd_send(idxd, IDXD_CMD_ENABLE_DEVICE, 0);

	if (rc < 0)

		return rc;

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;

	idxd_cmd_exec(idxd, IDXD_CMD_ENABLE_DEVICE, 0, &status);



	/* If the command is successful or if the device was enabled */

	if (status != IDXD_CMDSTS_SUCCESS &&
@@ -405,58 +419,29 @@ int idxd_device_enable(struct idxd_device *idxd) 
int idxd_device_disable(struct idxd_device *idxd)

{

	struct device *dev = &idxd->pdev->dev;

	int rc;

	u32 status;



	lockdep_assert_held(&idxd->dev_lock);

	if (!idxd_is_enabled(idxd)) {

		dev_dbg(dev, "Device is not enabled\n");

		return 0;

	}



	rc = idxd_cmd_send(idxd, IDXD_CMD_DISABLE_DEVICE, 0);

	if (rc < 0)

		return rc;

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;

	idxd_cmd_exec(idxd, IDXD_CMD_DISABLE_DEVICE, 0, &status);



	/* If the command is successful or if the device was disabled */

	if (status != IDXD_CMDSTS_SUCCESS &&

	    !(status & IDXD_CMDSTS_ERR_DIS_DEV_EN)) {

		dev_dbg(dev, "%s: err_code: %#x\n", __func__, status);

		rc = -ENXIO;

		return rc;

		return -ENXIO;

	}



	idxd->state = IDXD_DEV_CONF_READY;

	return 0;

}



int __idxd_device_reset(struct idxd_device *idxd)

{

	u32 status;

	int rc;



	rc = idxd_cmd_send(idxd, IDXD_CMD_RESET_DEVICE, 0);

	if (rc < 0)

		return rc;

	rc = idxd_cmd_wait(idxd, &status, IDXD_REG_TIMEOUT);

	if (rc < 0)

		return rc;



	return 0;

}



int idxd_device_reset(struct idxd_device *idxd)

void idxd_device_reset(struct idxd_device *idxd)

{

	unsigned long flags;

	int rc;



	spin_lock_irqsave(&idxd->dev_lock, flags);

	rc = __idxd_device_reset(idxd);

	spin_unlock_irqrestore(&idxd->dev_lock, flags);

	return rc;

	idxd_cmd_exec(idxd, IDXD_CMD_RESET_DEVICE, 0, NULL);

}



/* Device configuration bits */

drivers/dma/idxd/idxd.h

+8 −3
Original line number Diff line number Diff line
@@ -142,6 +142,7 @@ enum idxd_device_state { 


enum idxd_device_flag {

	IDXD_FLAG_CONFIGURABLE = 0,

	IDXD_FLAG_CMD_RUNNING,

};



struct idxd_device {
@@ -158,6 +159,7 @@ struct idxd_device { 
	void __iomem *reg_base;



	spinlock_t dev_lock;	/* spinlock for device */

	struct completion *cmd_done;

	struct idxd_group *groups;

	struct idxd_wq *wqs;

	struct idxd_engine *engines;
@@ -180,12 +182,14 @@ struct idxd_device { 
	int nr_tokens;		/* non-reserved tokens */



	union sw_err_reg sw_err;



	wait_queue_head_t cmd_waitq;

	struct msix_entry *msix_entries;

	int num_wq_irqs;

	struct idxd_irq_entry *irq_entries;



	struct dma_device dma_dev;

	struct workqueue_struct *wq;

	struct work_struct work;

};



/* IDXD software descriptor */
@@ -273,10 +277,10 @@ int idxd_mask_msix_vector(struct idxd_device *idxd, int vec_id); 
int idxd_unmask_msix_vector(struct idxd_device *idxd, int vec_id);



/* device control */

void idxd_device_init_reset(struct idxd_device *idxd);

int idxd_device_enable(struct idxd_device *idxd);

int idxd_device_disable(struct idxd_device *idxd);

int idxd_device_reset(struct idxd_device *idxd);

int __idxd_device_reset(struct idxd_device *idxd);

void idxd_device_reset(struct idxd_device *idxd);

void idxd_device_cleanup(struct idxd_device *idxd);

int idxd_device_config(struct idxd_device *idxd);

void idxd_device_wqs_clear_state(struct idxd_device *idxd);
@@ -286,6 +290,7 @@ int idxd_wq_alloc_resources(struct idxd_wq *wq); 
void idxd_wq_free_resources(struct idxd_wq *wq);

int idxd_wq_enable(struct idxd_wq *wq);

int idxd_wq_disable(struct idxd_wq *wq);

void idxd_wq_drain(struct idxd_wq *wq);

int idxd_wq_map_portal(struct idxd_wq *wq);

void idxd_wq_unmap_portal(struct idxd_wq *wq);

drivers/dma/idxd/init.c

+8 −6
Original line number Diff line number Diff line
@@ -146,6 +146,7 @@ static int idxd_setup_internals(struct idxd_device *idxd) 
	struct device *dev = &idxd->pdev->dev;

	int i;



	init_waitqueue_head(&idxd->cmd_waitq);

	idxd->groups = devm_kcalloc(dev, idxd->max_groups,

				    sizeof(struct idxd_group), GFP_KERNEL);

	if (!idxd->groups)
@@ -182,6 +183,10 @@ static int idxd_setup_internals(struct idxd_device *idxd) 
		idxd->engines[i].id = i;

	}



	idxd->wq = create_workqueue(dev_name(dev));

	if (!idxd->wq)

		return -ENOMEM;



	return 0;

}
@@ -277,9 +282,7 @@ static int idxd_probe(struct idxd_device *idxd) 
	int rc;



	dev_dbg(dev, "%s entered and resetting device\n", __func__);

	rc = idxd_device_reset(idxd);

	if (rc < 0)

		return rc;

	idxd_device_init_reset(idxd);

	dev_dbg(dev, "IDXD reset complete\n");



	idxd_read_caps(idxd);
@@ -414,11 +417,8 @@ static void idxd_shutdown(struct pci_dev *pdev) 
	int rc, i;

	struct idxd_irq_entry *irq_entry;

	int msixcnt = pci_msix_vec_count(pdev);

	unsigned long flags;



	spin_lock_irqsave(&idxd->dev_lock, flags);

	rc = idxd_device_disable(idxd);

	spin_unlock_irqrestore(&idxd->dev_lock, flags);

	if (rc)

		dev_err(&pdev->dev, "Disabling device failed\n");
@@ -434,6 +434,8 @@ static void idxd_shutdown(struct pci_dev *pdev) 
		idxd_flush_pending_llist(irq_entry);

		idxd_flush_work_list(irq_entry);

	}



	destroy_workqueue(idxd->wq);

}



static void idxd_remove(struct pci_dev *pdev)

drivers/dma/idxd/irq.c

+19 −22
Original line number Diff line number Diff line
@@ -23,16 +23,13 @@ void idxd_device_wqs_clear_state(struct idxd_device *idxd) 
	}

}



static int idxd_restart(struct idxd_device *idxd)

static void idxd_device_reinit(struct work_struct *work)

{

	int i, rc;



	lockdep_assert_held(&idxd->dev_lock);



	rc = __idxd_device_reset(idxd);

	if (rc < 0)

		goto out;

	struct idxd_device *idxd = container_of(work, struct idxd_device, work);

	struct device *dev = &idxd->pdev->dev;

	int rc, i;



	idxd_device_reset(idxd);

	rc = idxd_device_config(idxd);

	if (rc < 0)

		goto out;
@@ -47,19 +44,16 @@ static int idxd_restart(struct idxd_device *idxd) 
		if (wq->state == IDXD_WQ_ENABLED) {

			rc = idxd_wq_enable(wq);

			if (rc < 0) {

				dev_warn(&idxd->pdev->dev,

					 "Unable to re-enable wq %s\n",

				dev_warn(dev, "Unable to re-enable wq %s\n",

					 dev_name(&wq->conf_dev));

			}

		}

	}



	return 0;

	return;



 out:

	idxd_device_wqs_clear_state(idxd);

	idxd->state = IDXD_DEV_HALTED;

	return rc;

}



irqreturn_t idxd_irq_handler(int vec, void *data)
@@ -78,7 +72,7 @@ irqreturn_t idxd_misc_thread(int vec, void *data) 
	struct device *dev = &idxd->pdev->dev;

	union gensts_reg gensts;

	u32 cause, val = 0;

	int i, rc;

	int i;

	bool err = false;



	cause = ioread32(idxd->reg_base + IDXD_INTCAUSE_OFFSET);
@@ -117,8 +111,8 @@ irqreturn_t idxd_misc_thread(int vec, void *data) 
	}



	if (cause & IDXD_INTC_CMD) {

		/* Driver does use command interrupts */

		val |= IDXD_INTC_CMD;

		complete(idxd->cmd_done);

	}



	if (cause & IDXD_INTC_OCCUPY) {
@@ -145,22 +139,25 @@ irqreturn_t idxd_misc_thread(int vec, void *data) 


	gensts.bits = ioread32(idxd->reg_base + IDXD_GENSTATS_OFFSET);

	if (gensts.state == IDXD_DEVICE_STATE_HALT) {

		spin_lock_bh(&idxd->dev_lock);

		idxd->state = IDXD_DEV_HALTED;

		if (gensts.reset_type == IDXD_DEVICE_RESET_SOFTWARE) {

			rc = idxd_restart(idxd);

			if (rc < 0)

				dev_err(&idxd->pdev->dev,

					"idxd restart failed, device halt.");

			/*

			 * If we need a software reset, we will throw the work

			 * on a system workqueue in order to allow interrupts

			 * for the device command completions.

			 */

			INIT_WORK(&idxd->work, idxd_device_reinit);

			queue_work(idxd->wq, &idxd->work);

		} else {

			spin_lock_bh(&idxd->dev_lock);

			idxd_device_wqs_clear_state(idxd);

			idxd->state = IDXD_DEV_HALTED;

			dev_err(&idxd->pdev->dev,

				"idxd halted, need %s.\n",

				gensts.reset_type == IDXD_DEVICE_RESET_FLR ?

				"FLR" : "system reset");

		}

			spin_unlock_bh(&idxd->dev_lock);

		}

	}



	idxd_unmask_msix_vector(idxd, irq_entry->id);

	return IRQ_HANDLED;

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