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Subject[PATCH v4 8/9] dmaengine: idxd: connect idxd to dmaengine subsystem
From
Date
Add plumbing for dmaengine subsystem connection. The driver register a DMA
device per DSA device. The channels are dynamically registered when a
workqueue is configured to be "kernel:dmanegine" type.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/idxd/Makefile | 2
drivers/dma/idxd/device.c | 5 +
drivers/dma/idxd/dma.c | 208 +++++++++++++++++++++++++++++++++++++++++++++
drivers/dma/idxd/idxd.h | 14 +++
drivers/dma/idxd/init.c | 30 ++++++
drivers/dma/idxd/irq.c | 87 +++++++++++++++++++
drivers/dma/idxd/submit.c | 4 +
drivers/dma/idxd/sysfs.c | 28 ++++++
8 files changed, 376 insertions(+), 2 deletions(-)
create mode 100644 drivers/dma/idxd/dma.c

diff --git a/drivers/dma/idxd/Makefile b/drivers/dma/idxd/Makefile
index 50eca12015e2..a036ba0e77d2 100644
--- a/drivers/dma/idxd/Makefile
+++ b/drivers/dma/idxd/Makefile
@@ -1,2 +1,2 @@
obj-$(CONFIG_INTEL_IDXD) += idxd.o
-idxd-y := init.o irq.o device.o sysfs.o submit.o
+idxd-y := init.o irq.o device.o sysfs.o submit.o dma.o
diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index d03cd61c390e..d02cc98bc6db 100644
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -5,7 +5,9 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/dmaengine.h>
#include <uapi/linux/idxd.h>
+#include "../dmaengine.h"
#include "idxd.h"
#include "registers.h"

@@ -189,6 +191,9 @@ int idxd_wq_alloc_resources(struct idxd_wq *wq)
sizeof(struct dsa_completion_record) * i;
desc->id = i;
desc->wq = wq;
+
+ dma_async_tx_descriptor_init(&desc->txd, &wq->dma_chan);
+ desc->txd.tx_submit = idxd_dma_tx_submit;
}

return 0;
diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
new file mode 100644
index 000000000000..2b7c63b1b129
--- /dev/null
+++ b/drivers/dma/idxd/dma.c
@@ -0,0 +1,208 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/device.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/dmaengine.h>
+#include <uapi/linux/idxd.h>
+#include "../dmaengine.h"
+#include "registers.h"
+#include "idxd.h"
+
+static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
+{
+ return container_of(c, struct idxd_wq, dma_chan);
+}
+
+void idxd_dma_complete_txd(struct idxd_desc *desc, bool force)
+{
+ struct dma_async_tx_descriptor *tx;
+ struct dmaengine_result res;
+ int complete = 1;
+
+ if (desc->completion->status == DSA_COMP_SUCCESS)
+ res.result = DMA_TRANS_NOERROR;
+ else if (desc->completion->status)
+ res.result = DMA_TRANS_WRITE_FAILED;
+ else if (force)
+ res.result = DMA_TRANS_ABORTED;
+ else
+ complete = 0;
+
+ tx = &desc->txd;
+ if (complete && tx->cookie) {
+ dma_cookie_complete(tx);
+ dma_descriptor_unmap(tx);
+ dmaengine_desc_get_callback_invoke(tx, &res);
+ tx->callback = NULL;
+ tx->callback_result = NULL;
+ }
+}
+
+static void op_flag_setup(unsigned long flags, u32 *desc_flags)
+{
+ *desc_flags = IDXD_OP_FLAG_CRAV | IDXD_OP_FLAG_RCR;
+ if (flags & DMA_PREP_INTERRUPT)
+ *desc_flags |= IDXD_OP_FLAG_RCI;
+}
+
+static inline void set_completion_address(struct idxd_desc *desc,
+ u64 *compl_addr)
+{
+ *compl_addr = desc->compl_dma;
+}
+
+static inline void idxd_prep_desc_common(struct idxd_wq *wq,
+ struct dsa_hw_desc *hw, char opcode,
+ u64 addr_f1, u64 addr_f2, u64 len,
+ u64 compl, u32 flags)
+{
+ hw->flags = flags;
+ hw->opcode = opcode;
+ hw->src_addr = addr_f1;
+ hw->dst_addr = addr_f2;
+ hw->xfer_size = len;
+ hw->priv = !!(wq->type == IDXD_WQT_KERNEL);
+ hw->completion_addr = compl;
+
+ /*
+ * Descriptor completion vectors are 1-8 for MSIX. We will round
+ * robin through the 8 vectors.
+ */
+ hw->int_handle = ++wq->vec_ptr;
+ wq->vec_ptr = wq->vec_ptr & 7;
+}
+
+static struct dma_async_tx_descriptor *
+idxd_dma_submit_memcpy(struct dma_chan *c, dma_addr_t dma_dest,
+ dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+ struct idxd_wq *wq = to_idxd_wq(c);
+ u32 desc_flags;
+ struct idxd_device *idxd = wq->idxd;
+ struct idxd_desc *desc;
+
+ if (wq->state != IDXD_WQ_ENABLED)
+ return NULL;
+
+ if (len > idxd->max_xfer_bytes)
+ return NULL;
+
+ op_flag_setup(flags, &desc_flags);
+ desc = idxd_alloc_desc(wq, false);
+ if (IS_ERR(desc))
+ return NULL;
+
+ idxd_prep_desc_common(wq, desc->hw, DSA_OPCODE_MEMMOVE,
+ dma_src, dma_dest, len, desc->compl_dma,
+ desc_flags);
+
+ desc->txd.flags = flags;
+
+ return &desc->txd;
+}
+
+static int idxd_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+ struct idxd_wq *wq = to_idxd_wq(chan);
+ struct device *dev = &wq->idxd->pdev->dev;
+
+ idxd_wq_get(wq);
+ dev_dbg(dev, "%s: client_count: %d\n", __func__,
+ idxd_wq_refcount(wq));
+ return 0;
+}
+
+static void idxd_dma_free_chan_resources(struct dma_chan *chan)
+{
+ struct idxd_wq *wq = to_idxd_wq(chan);
+ struct device *dev = &wq->idxd->pdev->dev;
+
+ idxd_wq_put(wq);
+ dev_dbg(dev, "%s: client_count: %d\n", __func__,
+ idxd_wq_refcount(wq));
+}
+
+static enum dma_status idxd_dma_tx_status(struct dma_chan *dma_chan,
+ dma_cookie_t cookie,
+ struct dma_tx_state *txstate)
+{
+ return dma_cookie_status(dma_chan, cookie, txstate);
+}
+
+/*
+ * issue_pending() does not need to do anything since tx_submit() does the job
+ * already.
+ */
+static void idxd_dma_issue_pending(struct dma_chan *dma_chan)
+{
+}
+
+dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+ struct dma_chan *c = tx->chan;
+ struct idxd_wq *wq = to_idxd_wq(c);
+ dma_cookie_t cookie;
+ int rc;
+ struct idxd_desc *desc = container_of(tx, struct idxd_desc, txd);
+
+ cookie = dma_cookie_assign(tx);
+
+ rc = idxd_submit_desc(wq, desc);
+ if (rc < 0) {
+ idxd_free_desc(wq, desc);
+ return rc;
+ }
+
+ return cookie;
+}
+
+int idxd_register_dma_device(struct idxd_device *idxd)
+{
+ struct dma_device *dma = &idxd->dma_dev;
+
+ INIT_LIST_HEAD(&dma->channels);
+ dma->dev = &idxd->pdev->dev;
+
+ if (idxd->hw.opcap.bits[0] & IDXD_OPCAP_MEMMOVE) {
+ dma_cap_set(DMA_MEMCPY, dma->cap_mask);
+ dma->device_prep_dma_memcpy = idxd_dma_submit_memcpy;
+ }
+
+ dma->device_tx_status = idxd_dma_tx_status;
+ dma->device_issue_pending = idxd_dma_issue_pending;
+ dma->device_alloc_chan_resources = idxd_dma_alloc_chan_resources;
+ dma->device_free_chan_resources = idxd_dma_free_chan_resources;
+
+ return dma_async_device_register(&idxd->dma_dev);
+}
+
+void idxd_unregister_dma_device(struct idxd_device *idxd)
+{
+ dma_async_device_unregister(&idxd->dma_dev);
+}
+
+int idxd_register_dma_channel(struct idxd_wq *wq)
+{
+ struct idxd_device *idxd = wq->idxd;
+ struct dma_device *dma = &idxd->dma_dev;
+ struct dma_chan *chan = &wq->dma_chan;
+ int rc;
+
+ memset(&wq->dma_chan, 0, sizeof(struct dma_chan));
+ chan->device = dma;
+ list_add_tail(&chan->device_node, &dma->channels);
+ rc = dma_async_device_channel_register(dma, chan);
+ if (rc < 0)
+ return rc;
+
+ return 0;
+}
+
+void idxd_unregister_dma_channel(struct idxd_wq *wq)
+{
+ dma_async_device_channel_unregister(&wq->idxd->dma_dev, &wq->dma_chan);
+}
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index d369b75468e3..7e2f1f6f8854 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -4,6 +4,7 @@
#define _IDXD_H_

#include <linux/sbitmap.h>
+#include <linux/dmaengine.h>
#include <linux/percpu-rwsem.h>
#include <linux/wait.h>
#include "registers.h"
@@ -97,6 +98,7 @@ struct idxd_wq {
int compls_size;
struct idxd_desc **descs;
struct sbitmap sbmap;
+ struct dma_chan dma_chan;
struct percpu_rw_semaphore submit_lock;
wait_queue_head_t submit_waitq;
char name[WQ_NAME_SIZE + 1];
@@ -169,6 +171,8 @@ struct idxd_device {
struct msix_entry *msix_entries;
int num_wq_irqs;
struct idxd_irq_entry *irq_entries;
+
+ struct dma_device dma_dev;
};

/* IDXD software descriptor */
@@ -177,6 +181,7 @@ struct idxd_desc {
dma_addr_t desc_dma;
struct dsa_completion_record *completion;
dma_addr_t compl_dma;
+ struct dma_async_tx_descriptor txd;
struct llist_node llnode;
struct list_head list;
int id;
@@ -256,4 +261,13 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc);
struct idxd_desc *idxd_alloc_desc(struct idxd_wq *wq, enum idxd_op_type optype);
void idxd_free_desc(struct idxd_wq *wq, struct idxd_desc *desc);

+/* dmaengine */
+int idxd_register_dma_device(struct idxd_device *idxd);
+void idxd_unregister_dma_device(struct idxd_device *idxd);
+int idxd_register_dma_channel(struct idxd_wq *wq);
+void idxd_unregister_dma_channel(struct idxd_wq *wq);
+void idxd_parse_completion_status(u8 status, enum dmaengine_tx_result *res);
+void idxd_dma_complete_txd(struct idxd_desc *desc, bool force);
+dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx);
+
#endif
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 229386464923..4ac95b011d04 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -15,6 +15,8 @@
#include <linux/device.h>
#include <linux/idr.h>
#include <uapi/linux/idxd.h>
+#include <linux/dmaengine.h>
+#include "../dmaengine.h"
#include "registers.h"
#include "idxd.h"

@@ -396,6 +398,32 @@ static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
return 0;
}

+static void idxd_flush_pending_llist(struct idxd_irq_entry *ie)
+{
+ struct idxd_desc *desc, *itr;
+ struct llist_node *head;
+
+ head = llist_del_all(&ie->pending_llist);
+ if (!head)
+ return;
+
+ llist_for_each_entry_safe(desc, itr, head, llnode) {
+ idxd_dma_complete_txd(desc, 1);
+ idxd_free_desc(desc->wq, desc);
+ }
+}
+
+static void idxd_flush_work_list(struct idxd_irq_entry *ie)
+{
+ struct idxd_desc *desc, *iter;
+
+ list_for_each_entry_safe(desc, iter, &ie->work_list, list) {
+ list_del(&desc->list);
+ idxd_dma_complete_txd(desc, 1);
+ idxd_free_desc(desc->wq, desc);
+ }
+}
+
static void idxd_shutdown(struct pci_dev *pdev)
{
struct idxd_device *idxd = pci_get_drvdata(pdev);
@@ -419,6 +447,8 @@ static void idxd_shutdown(struct pci_dev *pdev)
synchronize_irq(idxd->msix_entries[i].vector);
if (i == 0)
continue;
+ idxd_flush_pending_llist(irq_entry);
+ idxd_flush_work_list(irq_entry);
}
}

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index de4b80973c2f..33394dd0af72 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -5,7 +5,9 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/io-64-nonatomic-lo-hi.h>
+#include <linux/dmaengine.h>
#include <uapi/linux/idxd.h>
+#include "../dmaengine.h"
#include "idxd.h"
#include "registers.h"

@@ -146,11 +148,96 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
return IRQ_HANDLED;
}

+static int irq_process_pending_llist(struct idxd_irq_entry *irq_entry,
+ int *processed)
+{
+ struct idxd_desc *desc, *t;
+ struct llist_node *head;
+ int queued = 0;
+
+ head = llist_del_all(&irq_entry->pending_llist);
+ if (!head)
+ return 0;
+
+ llist_for_each_entry_safe(desc, t, head, llnode) {
+ if (desc->completion->status) {
+ idxd_dma_complete_txd(desc, 0);
+ idxd_free_desc(desc->wq, desc);
+ (*processed)++;
+ } else {
+ list_add_tail(&desc->list, &irq_entry->work_list);
+ queued++;
+ }
+ }
+
+ return queued;
+}
+
+static int irq_process_work_list(struct idxd_irq_entry *irq_entry,
+ int *processed)
+{
+ struct list_head *node, *next;
+ int queued = 0;
+
+ if (list_empty(&irq_entry->work_list))
+ return 0;
+
+ list_for_each_safe(node, next, &irq_entry->work_list) {
+ struct idxd_desc *desc =
+ container_of(node, struct idxd_desc, list);
+
+ if (desc->completion->status) {
+ list_del(&desc->list);
+ /* process and callback */
+ idxd_dma_complete_txd(desc, 0);
+ idxd_free_desc(desc->wq, desc);
+ (*processed)++;
+ } else {
+ queued++;
+ }
+ }
+
+ return queued;
+}
+
irqreturn_t idxd_wq_thread(int irq, void *data)
{
struct idxd_irq_entry *irq_entry = data;
+ int rc, processed = 0, retry = 0;
+
+ /*
+ * There are two lists we are processing. The pending_llist is where
+ * submmiter adds all the submitted descriptor after sending it to
+ * the workqueue. It's a lockless singly linked list. The work_list
+ * is the common linux double linked list. We are in a scenario of
+ * multiple producers and a single consumer. The producers are all
+ * the kernel submitters of descriptors, and the consumer is the
+ * kernel irq handler thread for the msix vector when using threaded
+ * irq. To work with the restrictions of llist to remain lockless,
+ * we are doing the following steps:
+ * 1. Iterate through the work_list and process any completed
+ * descriptor. Delete the completed entries during iteration.
+ * 2. llist_del_all() from the pending list.
+ * 3. Iterate through the llist that was deleted from the pending list
+ * and process the completed entries.
+ * 4. If the entry is still waiting on hardware, list_add_tail() to
+ * the work_list.
+ * 5. Repeat until no more descriptors.
+ */
+ do {
+ rc = irq_process_work_list(irq_entry, &processed);
+ if (rc != 0) {
+ retry++;
+ continue;
+ }
+
+ rc = irq_process_pending_llist(irq_entry, &processed);
+ } while (rc != 0 && retry != 10);

idxd_unmask_msix_vector(irq_entry->idxd, irq_entry->id);

+ if (processed == 0)
+ return IRQ_NONE;
+
return IRQ_HANDLED;
}
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index 20c683870046..031e4a9e8f10 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -87,7 +87,9 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
* Pending the descriptor to the lockless list for the irq_entry
* that we designated the descriptor to.
*/
- llist_add(&desc->llnode, &idxd->irq_entries[vec].pending_llist);
+ if (desc->txd.flags & DMA_PREP_INTERRUPT)
+ llist_add(&desc->llnode,
+ &idxd->irq_entries[vec].pending_llist);

return 0;
}
diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index b6da47b52116..bcbd6020c8ee 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -55,6 +55,14 @@ static inline bool is_idxd_wq_dev(struct device *dev)
return dev ? dev->type == &idxd_wq_device_type : false;
}

+static inline bool is_idxd_wq_dmaengine(struct idxd_wq *wq)
+{
+ if (wq->type == IDXD_WQT_KERNEL &&
+ strcmp(wq->name, "dmaengine") == 0)
+ return true;
+ return false;
+}
+
static int idxd_config_bus_match(struct device *dev,
struct device_driver *drv)
{
@@ -122,6 +130,12 @@ static int idxd_config_bus_probe(struct device *dev)
spin_unlock_irqrestore(&idxd->dev_lock, flags);
dev_info(dev, "Device %s enabled\n", dev_name(dev));

+ rc = idxd_register_dma_device(idxd);
+ if (rc < 0) {
+ spin_unlock_irqrestore(&idxd->dev_lock, flags);
+ dev_dbg(dev, "Failed to register dmaengine device\n");
+ return rc;
+ }
return 0;
} else if (is_idxd_wq_dev(dev)) {
struct idxd_wq *wq = confdev_to_wq(dev);
@@ -194,6 +208,16 @@ static int idxd_config_bus_probe(struct device *dev)
wq->client_count = 0;

dev_info(dev, "wq %s enabled\n", dev_name(&wq->conf_dev));
+
+ if (is_idxd_wq_dmaengine(wq)) {
+ rc = idxd_register_dma_channel(wq);
+ if (rc < 0) {
+ dev_dbg(dev, "DMA channel register failed\n");
+ mutex_unlock(&wq->wq_lock);
+ return rc;
+ }
+ }
+
mutex_unlock(&wq->wq_lock);
return 0;
}
@@ -215,6 +239,9 @@ static void disable_wq(struct idxd_wq *wq)
return;
}

+ if (is_idxd_wq_dmaengine(wq))
+ idxd_unregister_dma_channel(wq);
+
if (idxd_wq_refcount(wq))
dev_warn(dev, "Clients has claim on wq %d: %d\n",
wq->id, idxd_wq_refcount(wq));
@@ -264,6 +291,7 @@ static int idxd_config_bus_remove(struct device *dev)
device_release_driver(&wq->conf_dev);
}

+ idxd_unregister_dma_device(idxd);
spin_lock_irqsave(&idxd->dev_lock, flags);
rc = idxd_device_disable(idxd);
spin_unlock_irqrestore(&idxd->dev_lock, flags);
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  Last update: 2020-01-07 21:42    [W:0.136 / U:0.732 seconds]
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