V4L/DVB (11616): cx18: Add a work queue for deferring empty buffer handoffs to the firmware
This change defers sending all CX18_CPU_DE_SET_MDL commands, for a stream with
an ongoing capture, by adding a work queue to handle sending such commands when
needed. This prevents any sleeps, caused by notifying the firmware of new
usable buffers, when a V4L2 application read() is being satisfied or when
an incoming buffer is processed by the cx18-NN-in work queue thread.
Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/cx18/cx18-driver.c b/drivers/media/video/cx18/cx18-driver.c
index 7975020..658cfbb 100644
--- a/drivers/media/video/cx18/cx18-driver.c
+++ b/drivers/media/video/cx18/cx18-driver.c
@@ -546,6 +546,47 @@
cx->card_i2c = cx->card->i2c;
}
+static int __devinit cx18_create_in_workq(struct cx18 *cx)
+{
+ snprintf(cx->in_workq_name, sizeof(cx->in_workq_name), "%s-in",
+ cx->v4l2_dev.name);
+ cx->in_work_queue = create_singlethread_workqueue(cx->in_workq_name);
+ if (cx->in_work_queue == NULL) {
+ CX18_ERR("Unable to create incoming mailbox handler thread\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static int __devinit cx18_create_out_workq(struct cx18 *cx)
+{
+ snprintf(cx->out_workq_name, sizeof(cx->out_workq_name), "%s-out",
+ cx->v4l2_dev.name);
+ cx->out_work_queue = create_workqueue(cx->out_workq_name);
+ if (cx->out_work_queue == NULL) {
+ CX18_ERR("Unable to create outgoing mailbox handler threads\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static void __devinit cx18_init_in_work_orders(struct cx18 *cx)
+{
+ int i;
+ for (i = 0; i < CX18_MAX_IN_WORK_ORDERS; i++) {
+ cx->in_work_order[i].cx = cx;
+ cx->in_work_order[i].str = cx->epu_debug_str;
+ INIT_WORK(&cx->in_work_order[i].work, cx18_in_work_handler);
+ }
+}
+
+static void __devinit cx18_init_out_work_orders(struct cx18 *cx)
+{
+ int i;
+ for (i = 0; i < CX18_MAX_OUT_WORK_ORDERS; i++)
+ INIT_WORK(&cx->out_work_order[i].work, cx18_out_work_handler);
+}
+
/* Precondition: the cx18 structure has been memset to 0. Only
the dev and instance fields have been filled in.
No assumptions on the card type may be made here (see cx18_init_struct2
@@ -553,7 +594,7 @@
*/
static int __devinit cx18_init_struct1(struct cx18 *cx)
{
- int i;
+ int ret;
cx->base_addr = pci_resource_start(cx->pci_dev, 0);
@@ -562,19 +603,18 @@
mutex_init(&cx->epu2apu_mb_lock);
mutex_init(&cx->epu2cpu_mb_lock);
- snprintf(cx->in_workq_name, sizeof(cx->in_workq_name), "%s-in",
- cx->v4l2_dev.name);
- cx->in_work_queue = create_singlethread_workqueue(cx->in_workq_name);
- if (cx->in_work_queue == NULL) {
- CX18_ERR("Unable to create incoming mailbox handler thread\n");
- return -ENOMEM;
+ ret = cx18_create_out_workq(cx);
+ if (ret)
+ return ret;
+
+ ret = cx18_create_in_workq(cx);
+ if (ret) {
+ destroy_workqueue(cx->out_work_queue);
+ return ret;
}
- for (i = 0; i < CX18_MAX_IN_WORK_ORDERS; i++) {
- cx->in_work_order[i].cx = cx;
- cx->in_work_order[i].str = cx->epu_debug_str;
- INIT_WORK(&cx->in_work_order[i].work, cx18_in_work_handler);
- }
+ cx18_init_out_work_orders(cx);
+ cx18_init_in_work_orders(cx);
/* start counting open_id at 1 */
cx->open_id = 1;
@@ -761,17 +801,17 @@
retval = -ENODEV;
goto err;
}
- if (cx18_init_struct1(cx)) {
- retval = -ENOMEM;
+
+ retval = cx18_init_struct1(cx);
+ if (retval)
goto err;
- }
CX18_DEBUG_INFO("base addr: 0x%08x\n", cx->base_addr);
/* PCI Device Setup */
retval = cx18_setup_pci(cx, pci_dev, pci_id);
if (retval != 0)
- goto free_workqueue;
+ goto free_workqueues;
/* map io memory */
CX18_DEBUG_INFO("attempting ioremap at 0x%08x len 0x%08x\n",
@@ -945,8 +985,9 @@
cx18_iounmap(cx);
free_mem:
release_mem_region(cx->base_addr, CX18_MEM_SIZE);
-free_workqueue:
+free_workqueues:
destroy_workqueue(cx->in_work_queue);
+ destroy_workqueue(cx->out_work_queue);
err:
if (retval == 0)
retval = -ENODEV;
@@ -1075,15 +1116,26 @@
if (atomic_read(&cx->tot_capturing) > 0)
cx18_stop_all_captures(cx);
- /* Interrupts */
+ /* Stop interrupts that cause incoming work to be queued */
cx18_sw1_irq_disable(cx, IRQ_CPU_TO_EPU | IRQ_APU_TO_EPU);
+
+ /* Incoming work can cause outgoing work, so clean up incoming first */
+ cx18_cancel_in_work_orders(cx);
+
+ /*
+ * An outgoing work order can have the only pointer to a dynamically
+ * allocated buffer, so we need to flush outgoing work and not just
+ * cancel it, so we don't lose the pointer and leak memory.
+ */
+ flush_workqueue(cx->out_work_queue);
+
+ /* Stop ack interrupts that may have been needed for work to finish */
cx18_sw2_irq_disable(cx, IRQ_CPU_TO_EPU_ACK | IRQ_APU_TO_EPU_ACK);
cx18_halt_firmware(cx);
- cx18_cancel_in_work_orders(cx);
-
destroy_workqueue(cx->in_work_queue);
+ destroy_workqueue(cx->out_work_queue);
cx18_streams_cleanup(cx, 1);