On Mon Aug 5 16:55:35 2024 +0200, Jacopo Mondi wrote:
> Currently the 'pispbe_schedule()' function does two things:
>
> 1) Tries to assemble a job by inspecting all the video node queues
> to make sure all the required buffers are available
> 2) Submit the job to the hardware
>
> The pispbe_schedule() function is called at:
>
> - video device start_streaming() time
> - video device qbuf() time
> - irq handler
>
> As assembling a job requires inspecting all queues, it is a rather
> time consuming operation which is better not run in IRQ context.
>
> To avoid executing the time consuming job creation in interrupt
> context split the job creation and job scheduling in two distinct
> operations. When a well-formed job is created, append it to the
> newly introduced 'pispbe->job_queue' where it will be dequeued from
> by the scheduling routine.
>
> As the per-node 'ready_queue' buffer list is only accessed in vb2 ops
> callbacks, protected by the node->queue_lock mutex, it is not necessary
> to guard it with a dedicated spinlock so drop it. Also use the
> spin_lock_irq() variant in all functions not called from an IRQ context
> where the spin_lock_irqsave() version was used.
>
> Reviewed-by: Naushir Patuck <[email protected]>
> Reviewed-by: Laurent Pinchart <[email protected]>
> Signed-off-by: Jacopo Mondi <[email protected]>
> Signed-off-by: Hans Verkuil <[email protected]>
Patch committed.
Thanks,
Hans Verkuil
.../media/platform/raspberrypi/pisp_be/pisp_be.c | 161 +++++++++++----------
1 file changed, 87 insertions(+), 74 deletions(-)
---
diff --git a/drivers/media/platform/raspberrypi/pisp_be/pisp_be.c
b/drivers/media/platform/raspberrypi/pisp_be/pisp_be.c
index 92c452891d6c..ccc6cb99868b 100644
--- a/drivers/media/platform/raspberrypi/pisp_be/pisp_be.c
+++ b/drivers/media/platform/raspberrypi/pisp_be/pisp_be.c
@@ -12,6 +12,7 @@
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
+#include <linux/slab.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ioctl.h>
#include <media/videobuf2-dma-contig.h>
@@ -161,8 +162,6 @@ struct pispbe_node {
struct mutex node_lock;
/* vb2_queue lock */
struct mutex queue_lock;
- /* Protect pispbe_node->ready_queue and pispbe_buffer->ready_list */
- spinlock_t ready_lock;
struct list_head ready_queue;
struct vb2_queue queue;
struct v4l2_format format;
@@ -190,6 +189,8 @@ struct pispbe_hw_enables {
/* Records a job configuration and memory addresses. */
struct pispbe_job_descriptor {
+ struct list_head queue;
+ struct pispbe_buffer *buffers[PISPBE_NUM_NODES];
dma_addr_t hw_dma_addrs[N_HW_ADDRESSES];
struct pisp_be_tiles_config *config;
struct pispbe_hw_enables hw_enables;
@@ -215,8 +216,10 @@ struct pispbe_dev {
unsigned int sequence;
u32 streaming_map;
struct pispbe_job queued_job, running_job;
- spinlock_t hw_lock; /* protects "hw_busy" flag and streaming_map */
+ /* protects "hw_busy" flag, streaming_map and job_queue */
+ spinlock_t hw_lock;
bool hw_busy; /* non-zero if a job is queued or is being started */
+ struct list_head job_queue;
int irq;
u32 hw_version;
u8 done, started;
@@ -440,42 +443,48 @@ static void pispbe_xlate_addrs(struct pispbe_dev *pispbe,
* For Output0, Output1, Tdn and Stitch, a buffer only needs to be
* available if the blocks are enabled in the config.
*
- * Needs to be called with hw_lock held.
+ * If all the buffers required to form a job are available, append the
+ * job descriptor to the job queue to be later queued to the HW.
*
* Returns 0 if a job has been successfully prepared, < 0 otherwise.
*/
-static int pispbe_prepare_job(struct pispbe_dev *pispbe,
- struct pispbe_job_descriptor *job)
+static int pispbe_prepare_job(struct pispbe_dev *pispbe)
{
+ struct pispbe_job_descriptor __free(kfree) *job = NULL;
struct pispbe_buffer *buf[PISPBE_NUM_NODES] = {};
+ unsigned int streaming_map;
unsigned int config_index;
struct pispbe_node *node;
- unsigned long flags;
- lockdep_assert_held(&pispbe->hw_lock);
+ lockdep_assert_irqs_enabled();
- memset(job, 0, sizeof(struct pispbe_job_descriptor));
+ scoped_guard(spinlock_irq, &pispbe->hw_lock) {
+ static const u32 mask = BIT(CONFIG_NODE) | BIT(MAIN_INPUT_NODE);
- if (((BIT(CONFIG_NODE) | BIT(MAIN_INPUT_NODE)) &
- pispbe->streaming_map) !=
- (BIT(CONFIG_NODE) | BIT(MAIN_INPUT_NODE)))
- return -ENODEV;
+ if ((pispbe->streaming_map & mask) != mask)
+ return -ENODEV;
+
+ /*
+ * Take a copy of streaming_map: nodes activated after this
+ * point are ignored when preparing this job.
+ */
+ streaming_map = pispbe->streaming_map;
+ }
+
+ job = kzalloc(sizeof(*job), GFP_KERNEL);
+ if (!job)
+ return -ENOMEM;
node = &pispbe->node[CONFIG_NODE];
- spin_lock_irqsave(&node->ready_lock, flags);
buf[CONFIG_NODE] = list_first_entry_or_null(&node->ready_queue,
struct pispbe_buffer,
ready_list);
- if (buf[CONFIG_NODE]) {
- list_del(&buf[CONFIG_NODE]->ready_list);
- pispbe->queued_job.buf[CONFIG_NODE] = buf[CONFIG_NODE];
- }
- spin_unlock_irqrestore(&node->ready_lock, flags);
-
- /* Exit early if no config buffer has been queued. */
if (!buf[CONFIG_NODE])
return -ENODEV;
+ list_del(&buf[CONFIG_NODE]->ready_list);
+ job->buffers[CONFIG_NODE] = buf[CONFIG_NODE];
+
config_index = buf[CONFIG_NODE]->vb.vb2_buf.index;
job->config = &pispbe->config[config_index];
job->tiles = pispbe->config_dma_addr +
@@ -495,7 +504,7 @@ static int pispbe_prepare_job(struct pispbe_dev *pispbe,
continue;
buf[i] = NULL;
- if (!(pispbe->streaming_map & BIT(i)))
+ if (!(streaming_map & BIT(i)))
continue;
if ((!(rgb_en & PISP_BE_RGB_ENABLE_OUTPUT0) &&
@@ -522,25 +531,28 @@ static int pispbe_prepare_job(struct pispbe_dev *pispbe,
node = &pispbe->node[i];
/* Pull a buffer from each V4L2 queue to form the queued job */
- spin_lock_irqsave(&node->ready_lock, flags);
buf[i] = list_first_entry_or_null(&node->ready_queue,
struct pispbe_buffer,
ready_list);
if (buf[i]) {
list_del(&buf[i]->ready_list);
- pispbe->queued_job.buf[i] = buf[i];
+ job->buffers[i] = buf[i];
}
- spin_unlock_irqrestore(&node->ready_lock, flags);
if (!buf[i] && !ignore_buffers)
goto err_return_buffers;
}
- pispbe->queued_job.valid = true;
-
/* Convert buffers to DMA addresses for the hardware */
pispbe_xlate_addrs(pispbe, job, buf);
+ scoped_guard(spinlock_irq, &pispbe->hw_lock) {
+ list_add_tail(&job->queue, &pispbe->job_queue);
+ }
+
+ /* Set job to NULL to avoid automatic release due to __free(). */
+ job = NULL;
+
return 0;
err_return_buffers:
@@ -551,33 +563,37 @@ err_return_buffers:
continue;
/* Return the buffer to the ready_list queue */
- spin_lock_irqsave(&n->ready_lock, flags);
list_add(&buf[i]->ready_list, &n->ready_queue);
- spin_unlock_irqrestore(&n->ready_lock, flags);
}
- memset(&pispbe->queued_job, 0, sizeof(pispbe->queued_job));
-
return -ENODEV;
}
static void pispbe_schedule(struct pispbe_dev *pispbe, bool clear_hw_busy)
{
- struct pispbe_job_descriptor job;
- unsigned long flags;
- int ret;
+ struct pispbe_job_descriptor *job;
+
+ scoped_guard(spinlock_irqsave, &pispbe->hw_lock) {
+ if (clear_hw_busy)
+ pispbe->hw_busy = false;
- spin_lock_irqsave(&pispbe->hw_lock, flags);
+ if (pispbe->hw_busy)
+ return;
- if (clear_hw_busy)
- pispbe->hw_busy = false;
+ job = list_first_entry_or_null(&pispbe->job_queue,
+ struct pispbe_job_descriptor,
+ queue);
+ if (!job)
+ return;
- if (pispbe->hw_busy)
- goto unlock_and_return;
+ list_del(&job->queue);
- ret = pispbe_prepare_job(pispbe, &job);
- if (ret)
- goto unlock_and_return;
+ for (unsigned int i = 0; i < PISPBE_NUM_NODES; i++)
+ pispbe->queued_job.buf[i] = job->buffers[i];
+ pispbe->queued_job.valid = true;
+
+ pispbe->hw_busy = true;
+ }
/*
* We can kick the job off without the hw_lock, as this can
@@ -585,16 +601,8 @@ static void pispbe_schedule(struct pispbe_dev *pispbe,
bool clear_hw_busy)
* only when the following job has been queued and an interrupt
* is rised.
*/
- pispbe->hw_busy = true;
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
-
- pispbe_queue_job(pispbe, &job);
-
- return;
-
-unlock_and_return:
- /* No job has been queued, just release the lock and return. */
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
+ pispbe_queue_job(pispbe, job);
+ kfree(job);
}
static void pispbe_isr_jobdone(struct pispbe_dev *pispbe,
@@ -846,18 +854,16 @@ static void pispbe_node_buffer_queue(struct vb2_buffer
*buf)
container_of(vbuf, struct pispbe_buffer, vb);
struct pispbe_node *node = vb2_get_drv_priv(buf->vb2_queue);
struct pispbe_dev *pispbe = node->pispbe;
- unsigned long flags;
dev_dbg(pispbe->dev, "%s: for node %s\n", __func__, NODE_NAME(node));
- spin_lock_irqsave(&node->ready_lock, flags);
list_add_tail(&buffer->ready_list, &node->ready_queue);
- spin_unlock_irqrestore(&node->ready_lock, flags);
/*
* Every time we add a buffer, check if there's now some work for the hw
* to do.
*/
- pispbe_schedule(pispbe, false);
+ if (!pispbe_prepare_job(pispbe))
+ pispbe_schedule(pispbe, false);
}
static int pispbe_node_start_streaming(struct vb2_queue *q, unsigned int count)
@@ -865,17 +871,16 @@ static int pispbe_node_start_streaming(struct vb2_queue
*q, unsigned int count)
struct pispbe_node *node = vb2_get_drv_priv(q);
struct pispbe_dev *pispbe = node->pispbe;
struct pispbe_buffer *buf, *tmp;
- unsigned long flags;
int ret;
ret = pm_runtime_resume_and_get(pispbe->dev);
if (ret < 0)
goto err_return_buffers;
- spin_lock_irqsave(&pispbe->hw_lock, flags);
- node->pispbe->streaming_map |= BIT(node->id);
- node->pispbe->sequence = 0;
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
+ scoped_guard(spinlock_irq, &pispbe->hw_lock) {
+ node->pispbe->streaming_map |= BIT(node->id);
+ node->pispbe->sequence = 0;
+ }
dev_dbg(pispbe->dev, "%s: for node %s (count %u)\n",
__func__, NODE_NAME(node), count);
@@ -883,17 +888,16 @@ static int pispbe_node_start_streaming(struct vb2_queue
*q, unsigned int count)
node->pispbe->streaming_map);
/* Maybe we're ready to run. */
- pispbe_schedule(pispbe, false);
+ if (!pispbe_prepare_job(pispbe))
+ pispbe_schedule(pispbe, false);
return 0;
err_return_buffers:
- spin_lock_irqsave(&pispbe->hw_lock, flags);
list_for_each_entry_safe(buf, tmp, &node->ready_queue, ready_list) {
list_del(&buf->ready_list);
vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
}
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
return ret;
}
@@ -902,8 +906,9 @@ static void pispbe_node_stop_streaming(struct vb2_queue *q)
{
struct pispbe_node *node = vb2_get_drv_priv(q);
struct pispbe_dev *pispbe = node->pispbe;
+ struct pispbe_job_descriptor *job, *temp;
struct pispbe_buffer *buf;
- unsigned long flags;
+ LIST_HEAD(tmp_list);
/*
* Now this is a bit awkward. In a simple M2M device we could just wait
@@ -915,11 +920,7 @@ static void pispbe_node_stop_streaming(struct vb2_queue *q)
* This may return buffers out of order.
*/
dev_dbg(pispbe->dev, "%s: for node %s\n", __func__, NODE_NAME(node));
- spin_lock_irqsave(&pispbe->hw_lock, flags);
do {
- unsigned long flags1;
-
- spin_lock_irqsave(&node->ready_lock, flags1);
buf = list_first_entry_or_null(&node->ready_queue,
struct pispbe_buffer,
ready_list);
@@ -927,15 +928,26 @@ static void pispbe_node_stop_streaming(struct vb2_queue
*q)
list_del(&buf->ready_list);
vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
}
- spin_unlock_irqrestore(&node->ready_lock, flags1);
} while (buf);
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
vb2_wait_for_all_buffers(&node->queue);
- spin_lock_irqsave(&pispbe->hw_lock, flags);
+ spin_lock_irq(&pispbe->hw_lock);
pispbe->streaming_map &= ~BIT(node->id);
- spin_unlock_irqrestore(&pispbe->hw_lock, flags);
+
+ if (pispbe->streaming_map == 0) {
+ /*
+ * If all nodes have stopped streaming release all jobs
+ * without holding the lock.
+ */
+ list_splice_init(&pispbe->job_queue, &tmp_list);
+ }
+ spin_unlock_irq(&pispbe->hw_lock);
+
+ list_for_each_entry_safe(job, temp, &tmp_list, queue) {
+ list_del(&job->queue);
+ kfree(job);
+ }
pm_runtime_mark_last_busy(pispbe->dev);
pm_runtime_put_autosuspend(pispbe->dev);
@@ -1393,7 +1405,6 @@ static int pispbe_init_node(struct pispbe_dev *pispbe,
unsigned int id)
mutex_init(&node->node_lock);
mutex_init(&node->queue_lock);
INIT_LIST_HEAD(&node->ready_queue);
- spin_lock_init(&node->ready_lock);
node->format.type = node->buf_type;
pispbe_node_def_fmt(node);
@@ -1677,6 +1688,8 @@ static int pispbe_probe(struct platform_device *pdev)
if (!pispbe)
return -ENOMEM;
+ INIT_LIST_HEAD(&pispbe->job_queue);
+
dev_set_drvdata(&pdev->dev, pispbe);
pispbe->dev = &pdev->dev;
platform_set_drvdata(pdev, pispbe);
