From: Dave Jiang <dave.jiang@intel.com>
To: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
vkoul@kernel.org
Cc: dan.j.williams@intel.com, tony.luck@intel.com,
jing.lin@intel.com, ashok.raj@intel.com,
sanjay.k.kumar@intel.com, megha.dey@intel.com,
jacob.jun.pan@intel.com, yi.l.liu@intel.com, axboe@kernel.dk,
akpm@linux-foundation.org, tglx@linutronix.de, mingo@redhat.com,
bp@alien8.de, fenghua.yu@intel.com, hpa@zytor.com
Subject: [PATCH RFC v2 06/14] dmaengine: add dma request submit and completion path support
Date: Thu, 12 Dec 2019 11:24:45 -0700 [thread overview]
Message-ID: <157617508579.42350.5174393499273822619.stgit@djiang5-desk3.ch.intel.com> (raw)
In-Reply-To: <157617487798.42350.4471714981643413895.stgit@djiang5-desk3.ch.intel.com>
There are several issues with the existing dmaengine submission APIs.
1. A new function pointer is introduced every time a new operation is
added.
2. The whole submission path requires locking and requires multiple API
calls with prep+submit+start engine.
A new DMA register function for request based DMA devices is added,
dma_async_request_device_register(). This allows the checking of parts for
dma requests that are setup.
A new submission API call that can start an I/O immediately in a single
call and will be lockless is being introduced. A helper function that
submits and wait is also added for consumers such as dmatest that will wait
on the completion of the I/O. And a helper function is added that completes
the I/O by either calling complete() or envoking the callback depending on
the setup for submission.
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
drivers/dma/dmaengine.c | 59 ++++++++++++++++++++++++++++++++++++++++
include/linux/dmaengine.h | 67 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 126 insertions(+)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 3c74402f1c34..5b053624f9e3 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1050,6 +1050,37 @@ static int __dma_async_device_register(struct dma_device *device)
return 0;
}
+/**
+ * dma_async_request_device_register - registers DMA devices found that
+ * support DMA requests.
+ * @device: &dma_device
+ */
+int dma_async_request_device_register(struct dma_device *device)
+{
+ int rc;
+
+ if (!device)
+ return -ENODEV;
+
+ /* validate device routines */
+ if (!device->dev) {
+ pr_err("DMA device must have dev\n");
+ return -EIO;
+ }
+
+ if (!device->device_submit_request) {
+ dev_err(device->dev, "Device has no op defined\n");
+ return -EIO;
+ }
+
+ rc = __dma_async_device_register(device);
+ if (rc != 0)
+ return rc;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(dma_async_request_device_register);
+
/**
* dma_async_device_register - registers DMA devices found
* @device: &dma_device
@@ -1232,6 +1263,34 @@ int dmaenginem_async_device_register(struct dma_device *device)
}
EXPORT_SYMBOL(dmaenginem_async_device_register);
+/**
+ * dmaenginem_async_request_device_register - registers DMA devices
+ * support DMA requests found
+ * @device: &dma_device
+ *
+ * The operation is managed and will be undone on driver detach.
+ */
+int dmaenginem_async_request_device_register(struct dma_device *device)
+{
+ void *p;
+ int ret;
+
+ p = devres_alloc(dmam_device_release, sizeof(void *), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+
+ ret = dma_async_request_device_register(device);
+ if (!ret) {
+ *(struct dma_device **)p = device;
+ devres_add(device->dev, p);
+ } else {
+ devres_free(p);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(dmaenginem_async_request_device_register);
+
struct dmaengine_unmap_pool {
struct kmem_cache *cache;
const char *name;
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 7bc8c3f8283f..220d241d71ed 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -461,6 +461,7 @@ enum dmaengine_tx_result {
DMA_TRANS_NOERROR = 0, /* SUCCESS */
DMA_TRANS_READ_FAILED, /* Source DMA read failed */
DMA_TRANS_WRITE_FAILED, /* Destination DMA write failed */
+ DMA_TRANS_ERROR, /* General error not rd/wr */
DMA_TRANS_ABORTED, /* Op never submitted / aborted */
};
@@ -831,6 +832,10 @@ struct dma_device {
dma_cookie_t cookie,
struct dma_tx_state *txstate);
void (*device_issue_pending)(struct dma_chan *chan);
+
+ /* function calls for request API */
+ int (*device_submit_request)(struct dma_chan *chan,
+ struct dma_request *req);
};
static inline int dmaengine_slave_config(struct dma_chan *chan,
@@ -1390,6 +1395,66 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
}
#endif
+/* dmaengine_submit_request - helper routine for caller to submit
+ * a DMA request.
+ * @chan: dma channel context
+ * @req: dma request context
+ */
+static inline int dmaengine_submit_request(struct dma_chan *chan,
+ struct dma_request *req)
+{
+ struct dma_device *ddev;
+
+ if (!chan)
+ return -EINVAL;
+
+ ddev = chan->device;
+ if (!ddev->device_submit_request)
+ return -EINVAL;
+
+ return ddev->device_submit_request(chan, req);
+}
+
+/* dmaengine_submit_request_and_wait - helper routine for caller to submit
+ * a DMA request and wait until
+ * completion or timeout.
+ * @chan: dma channel context
+ * @req: dma request context
+ * @timeout: time in jiffies to wait for completion timeout. A timeout of 0
+ * equals to wait indefinitely.
+ */
+static inline int dmaengine_submit_request_and_wait(struct dma_chan *chan,
+ struct dma_request *req,
+ int timeout)
+{
+ int rc;
+ DECLARE_COMPLETION_ONSTACK(done);
+
+ req->rq_private = &done;
+ rc = dmaengine_submit_request(chan, req);
+ if (rc < 0)
+ return rc;
+
+ if (timeout)
+ return wait_for_completion_timeout(&done, timeout);
+
+ wait_for_completion(&done);
+ return 0;
+}
+
+/* dmaengine_request_complete - helper function to complete dma request.
+ * If callback exists will envoke callback.
+ *
+ * @req - dma request context
+ */
+static inline void dmaengine_request_complete(struct dma_request *req)
+{
+ if (req->rq_private)
+ complete(req->rq_private);
+ else if (req->callback)
+ req->callback(req->callback_param, &req->result);
+}
+
#ifdef CONFIG_DMA_ENGINE_REQUEST
struct dma_request *dma_chan_alloc_request(struct dma_chan *chan);
void dma_chan_free_request(struct dma_chan *chan, struct dma_request *rq);
@@ -1454,7 +1519,9 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc)
/* --- DMA device --- */
int dma_async_device_register(struct dma_device *device);
+int dma_async_request_device_register(struct dma_device *device);
int dmaenginem_async_device_register(struct dma_device *device);
+int dmaenginem_async_request_device_register(struct dma_device *device);
void dma_async_device_unregister(struct dma_device *device);
int dma_async_device_channel_register(struct dma_device *device,
struct dma_chan *chan);
next prev parent reply other threads:[~2019-12-12 18:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 18:24 [PATCH RFC v2 00/14] idxd driver for Intel Data Streaming Accelerator Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 02/14] dmaengine: break out channel registration Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 03/14] dmaengine: add new dma device registration Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 04/14] mm: create common code from request allocation based from blk-mq code Dave Jiang
2019-12-13 0:43 ` Andrew Morton
2019-12-13 22:06 ` Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 05/14] dmaengine: add dma_request support functions Dave Jiang
2019-12-12 18:24 ` Dave Jiang [this message]
2019-12-12 18:24 ` [PATCH RFC v2 07/14] dmaengine: update dmatest to support dma request Dave Jiang
2019-12-12 18:24 ` [PATCH RFC v2 08/14] dmaengine: idxd: Init and probe for Intel data accelerators Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 09/14] dmaengine: idxd: add configuration component of driver Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 10/14] dmaengine: idxd: add descriptor manipulation routines Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 11/14] dmaengine: idxd: connect idxd to dmaengine subsystem Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 12/14] dmaengine: request submit optimization Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 13/14] dmaengine: idxd: add char driver to expose submission portal to userland Dave Jiang
2019-12-12 18:25 ` [PATCH RFC v2 14/14] dmaengine: idxd: add sysfs ABI for idxd driver Dave Jiang
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