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, 1 deletions

diff --git a/drivers/media/video/cx18/cx18-mailbox.h b/drivers/media/video/cx18/cx18-mailbox.h
index 54758f32db1e..002c0526afa0 100644
--- a/drivers/media/video/cx18/cx18-mailbox.h
+++ b/drivers/media/video/cx18/cx18-mailbox.h
@@ -37,6 +37,17 @@
 
 struct cx18;
 
+/*
+ * This structure is used by CPU to provide completed buffers information
+ * Its structure is dictrated by the layout of the SCB, required by the
+ * firmware, but its defintion needs to be here, instead of in cx18-scb.h,
+ * for mailbox work order scheduling
+ */
+struct cx18_mdl_ack {
+    u32 id;        /* ID of a completed MDL */
+    u32 data_used; /* Total data filled in the MDL for buffer 'id' */
+};
+
 /* The cx18_mailbox struct is the mailbox structure which is used for passing
    messages between processors */
 struct cx18_mailbox {
@@ -73,6 +84,9 @@ int cx18_vapi_result(struct cx18 *cx, u32 data[MAX_MB_ARGUMENTS], u32 cmd,
 int cx18_vapi(struct cx18 *cx, u32 cmd, int args, ...);
 int cx18_api_func(void *priv, u32 cmd, int in, int out,
                 u32 data[CX2341X_MBOX_MAX_DATA]);
-long cx18_mb_ack(struct cx18 *cx, const struct cx18_mailbox *mb, int rpu);
+
+void cx18_api_epu_cmd_irq(struct cx18 *cx, int rpu);
+
+void cx18_epu_work_handler(struct work_struct *work);
 
 #endif