V4L/DVB (9720): cx18: Major rewrite of interrupt handling for incoming mailbox processing

A major rewrite of interrupt handling for incoming mailbox processing, to split
the timing critical steps from the the deferrable steps as the sending XPU on
the CX23418 will time out and overwrite our incoming mailboxes rather quickly.
Setup a pool of work "order forms" for the irq handler to send jobs to the new
work handler routine which uses the kernel default work queue to do the
deferrable work.  Started optimizing some of the cx18-io calls as they are now
the low hanging fruit for recoving microseconds back from the timeline.
Future optimizations will get rid of mmio read retries, mmio stats logging, and
combine smaller functions in the irq path into the larger ones to save ~2 us
each.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 15 insertions, 118 deletions

diff --git a/drivers/media/video/cx18/cx18-irq.c b/drivers/media/video/cx18/cx18-irq.c
index 4912b3c8e6a..bc36a6b8f77 100644
--- a/drivers/media/video/cx18/cx18-irq.c
+++ b/drivers/media/video/cx18/cx18-irq.c
@@ -21,121 +21,9 @@
 
 #include "cx18-driver.h"
 #include "cx18-io.h"
-#include "cx18-firmware.h"
-#include "cx18-fileops.h"
-#include "cx18-queue.h"
 #include "cx18-irq.h"
-#include "cx18-ioctl.h"
 #include "cx18-mailbox.h"
-#include "cx18-vbi.h"
 #include "cx18-scb.h"
-#include "cx18-dvb.h"
-
-void cx18_work_handler(struct work_struct *work)
-{
-	struct cx18 *cx = container_of(work, struct cx18, work);
-	if (test_and_clear_bit(CX18_F_I_WORK_HANDLER_DVB, &cx->i_flags))
-		cx18_dvb_work_handler(cx);
-}
-
-static void epu_dma_done(struct cx18 *cx, struct cx18_mailbox *mb, int rpu)
-{
-	u32 handle = mb->args[0];
-	struct cx18_stream *s = NULL;
-	struct cx18_buffer *buf;
-	u32 off;
-	int i;
-	int id;
-
-	for (i = 0; i < CX18_MAX_STREAMS; i++) {
-		s = &cx->streams[i];
-		if ((handle == s->handle) && (s->dvb.enabled))
-			break;
-		if (s->v4l2dev && handle == s->handle)
-			break;
-	}
-	if (i == CX18_MAX_STREAMS) {
-		CX18_WARN("Got DMA done notification for unknown/inactive"
-			  " handle %d\n", handle);
-		mb->error = CXERR_NOT_OPEN;
-		mb->cmd = 0;
-		cx18_mb_ack(cx, mb, rpu);
-		return;
-	}
-
-	off = mb->args[1];
-	if (mb->args[2] != 1)
-		CX18_WARN("Ack struct = %d for %s\n",
-			mb->args[2], s->name);
-	id = cx18_read_enc(cx, off);
-	buf = cx18_queue_get_buf_irq(s, id, cx18_read_enc(cx, off + 4));
-	CX18_DEBUG_HI_DMA("DMA DONE for %s (buffer %d)\n", s->name, id);
-	if (buf) {
-		cx18_buf_sync_for_cpu(s, buf);
-		if (s->type == CX18_ENC_STREAM_TYPE_TS && s->dvb.enabled) {
-			CX18_DEBUG_HI_DMA("TS recv bytesused = %d\n",
-					buf->bytesused);
-
-			set_bit(CX18_F_I_WORK_HANDLER_DVB, &cx->i_flags);
-			set_bit(CX18_F_I_HAVE_WORK, &cx->i_flags);
-		} else
-			set_bit(CX18_F_B_NEED_BUF_SWAP, &buf->b_flags);
-	} else {
-		CX18_WARN("Could not find buf %d for stream %s\n",
-				cx18_read_enc(cx, off), s->name);
-	}
-	mb->error = 0;
-	mb->cmd = 0;
-	cx18_mb_ack(cx, mb, rpu);
-	wake_up(&cx->dma_waitq);
-	if (s->id != -1)
-		wake_up(&s->waitq);
-}
-
-static void epu_debug(struct cx18 *cx, struct cx18_mailbox *mb, int rpu)
-{
-	char str[256] = { 0 };
-	char *p;
-
-	if (mb->args[1]) {
-		cx18_setup_page(cx, mb->args[1]);
-		cx18_memcpy_fromio(cx, str, cx->enc_mem + mb->args[1], 252);
-		str[252] = 0;
-	}
-	cx18_mb_ack(cx, mb, rpu);
-	CX18_DEBUG_INFO("%x %s\n", mb->args[0], str);
-	p = strchr(str, '.');
-	if (!test_bit(CX18_F_I_LOADED_FW, &cx->i_flags) && p && p > str)
-		CX18_INFO("FW version: %s\n", p - 1);
-}
-
-static void epu_cmd(struct cx18 *cx, u32 sw1)
-{
-	struct cx18_mailbox mb;
-
-	if (sw1 & IRQ_CPU_TO_EPU) {
-		cx18_memcpy_fromio(cx, &mb, &cx->scb->cpu2epu_mb, sizeof(mb));
-		mb.error = 0;
-
-		switch (mb.cmd) {
-		case CX18_EPU_DMA_DONE:
-			epu_dma_done(cx, &mb, CPU);
-			break;
-		case CX18_EPU_DEBUG:
-			epu_debug(cx, &mb, CPU);
-			break;
-		default:
-			CX18_WARN("Unknown CPU_TO_EPU mailbox command %#08x\n",
-				  mb.cmd);
-			break;
-		}
-	}
-
-	if (sw1 & IRQ_APU_TO_EPU) {
-		cx18_memcpy_fromio(cx, &mb, &cx->scb->apu2epu_mb, sizeof(mb));
-		CX18_WARN("Unknown APU_TO_EPU mailbox command %#08x\n", mb.cmd);
-	}
-}
 
 static void xpu_ack(struct cx18 *cx, u32 sw2)
 {
@@ -145,6 +33,14 @@ static void xpu_ack(struct cx18 *cx, u32 sw2)
 		wake_up(&cx->mb_apu_waitq);
 }
 
+static void epu_cmd(struct cx18 *cx, u32 sw1)
+{
+	if (sw1 & IRQ_CPU_TO_EPU)
+		cx18_api_epu_cmd_irq(cx, CPU);
+	if (sw1 & IRQ_APU_TO_EPU)
+		cx18_api_epu_cmd_irq(cx, APU);
+}
+
 irqreturn_t cx18_irq_handler(int irq, void *dev_id)
 {
 	struct cx18 *cx = (struct cx18 *)dev_id;
@@ -170,6 +66,13 @@ irqreturn_t cx18_irq_handler(int irq, void *dev_id)
 		CX18_DEBUG_HI_IRQ("received interrupts "
 				  "SW1: %x  SW2: %x  HW2: %x\n", sw1, sw2, hw2);
 
+	/*
+	 * SW1 responses have to happen first.  The sending XPU times out the
+	 * incoming mailboxes on us rather rapidly.
+	 */
+	if (sw1)
+		epu_cmd(cx, sw1);
+
 	/* To do: interrupt-based I2C handling
 	if (hw2 & (HW2_I2C1_INT|HW2_I2C2_INT)) {
 	}
@@ -178,11 +81,5 @@ irqreturn_t cx18_irq_handler(int irq, void *dev_id)
 	if (sw2)
 		xpu_ack(cx, sw2);
 
-	if (sw1)
-		epu_cmd(cx, sw1);
-
-	if (test_and_clear_bit(CX18_F_I_HAVE_WORK, &cx->i_flags))
-		schedule_work(&cx->work);
-
 	return (sw1 || sw2 || hw2) ? IRQ_HANDLED : IRQ_NONE;
 }