V4L/DVB (7540): em28xx: convert to use videobuf-vmalloc

The usage of videobuf-vmalloc allows to cleanup em28xx logic.

Also, it reduced its size by about 5.42% on i386 arch (and about 7.5% on x86_64):

  39113    4876      40   44029    abfd old/em28xx.ko
  36731    4868      40   41639    a2a7 /home/v4l/master/v4l/em28xx.ko

Also, the preliminary tests, made on a single core 1.5 MHz Centrino showed
that CPU usage reduced from 42%-75% to 28%-33% (reports from "top") command.

A test with time command presented an even better result:

This is the performance tests I did, running code_example to get 1,000 frames
@29.995 Hz (about 35 seconds of stream), tested on a i386 machine, running at
1,5GHz:

	The old driver:

$ time -f "%E: %Us User time, %Ss Kernel time, %P CPU used" ./capture_example
0:34.21: 8.22s User time, 25.16s Kernel time, 97% CPU used

	The videobuf-based driver:

$ time -f "%E: %Us User time, %Ss Kernel time, %P CPU used" ./capture_example
0:35.36: 0.01s User time, 0.05s Kernel time, 0% CPU used

	Conclusion:

The time consumption to receive the stream where reduced from about 33.38
seconds to 0.05 seconds.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 68 insertions, 26 deletions

diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 04e0e48ecab..dd18ceb30a4 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -26,12 +26,12 @@
 #define _EM28XX_H
 
 #include <linux/videodev2.h>
+#include <media/videobuf-vmalloc.h>
+
 #include <linux/i2c.h>
 #include <linux/mutex.h>
 #include <media/ir-kbd-i2c.h>
 
-#define UNSET -1
-
 /* maximum number of em28xx boards */
 #define EM28XX_MAXBOARDS 4 /*FIXME: should be bigger */
 
@@ -81,31 +81,69 @@
 /* time in msecs to wait for i2c writes to finish */
 #define EM2800_I2C_WRITE_TIMEOUT 20
 
-/* the various frame states */
-enum em28xx_frame_state {
-        F_UNUSED = 0,
-        F_QUEUED,
-        F_GRABBING,
-        F_DONE,
-        F_ERROR,
-};
-
-/* stream states */
 enum em28xx_stream_state {
         STREAM_OFF,
         STREAM_INTERRUPT,
         STREAM_ON,
 };
 
-/* frames */
-struct em28xx_frame_t {
-        void *bufmem;
-        struct v4l2_buffer buf;
-        enum em28xx_frame_state state;
+struct em28xx_usb_isoc_ctl {
+                /* max packet size of isoc transaction */
+        int                             max_pkt_size;
+
+                /* number of allocated urbs */
+        int                             num_bufs;
+
+                /* urb for isoc transfers */
+        struct urb                      **urb;
+
+                /* transfer buffers for isoc transfer */
+        char                            **transfer_buffer;
+
+                /* Last buffer command and region */
+        u8                              cmd;
+        int                             pos, size, pktsize;
+
+                /* Last field: ODD or EVEN? */
+        int                             field;
+
+                /* Stores incomplete commands */
+        u32                             tmp_buf;
+        int                             tmp_buf_len;
+
+                /* Stores already requested buffers */
+        struct em28xx_buffer            *buf;
+
+                /* Stores the number of received fields */
+        int                             nfields;
+};
+
+struct em28xx_fmt {
+        char  *name;
+        u32   fourcc;          /* v4l2 format id */
+};
+
+/* buffer for one video frame */
+struct em28xx_buffer {
+        /* common v4l buffer stuff -- must be first */
+        struct videobuf_buffer vb;
+
+        struct em28xx_fmt *fmt;
+
         struct list_head frame;
-        unsigned long vma_use_count;
         int top_field;
-        int fieldbytesused;
+        int receiving;
+};
+
+struct em28xx_dmaqueue {
+        struct list_head       active;
+        struct list_head       queued;
+        struct timer_list      timeout;
+
+        wait_queue_head_t          wq;
+
+        /* Counters to control buffer fill */
+        int                        pos;
 };
 
 /* io methods */
@@ -255,10 +293,6 @@ struct em28xx {
         int mute;
         int volume;
         /* frame properties */
-        struct em28xx_frame_t frame[EM28XX_NUM_FRAMES]; /* list of frames */
-        int num_frames;         /* number of frames currently in use */
-        unsigned int frame_count;       /* total number of transfered frames */
-        struct em28xx_frame_t *frame_current;   /* the frame that is being filled */
         int width;              /* current frame width */
         int height;             /* current frame height */
         int frame_size;         /* current frame size */
@@ -277,7 +311,6 @@ struct em28xx {
 
         /* states */
         enum em28xx_dev_state state;
-        enum em28xx_stream_state stream;
         enum em28xx_io_method io;
 
         struct work_struct         request_module_wk;
@@ -292,6 +325,11 @@ struct em28xx {
 
         unsigned char eedata[256];
 
+        /* Isoc control struct */
+        struct em28xx_dmaqueue vidq;
+        struct em28xx_usb_isoc_ctl isoc_ctl;
+        spinlock_t slock;
+
         /* usb transfer */
         struct usb_device *udev;        /* the usb device */
         int alt;                /* alternate */
@@ -315,6 +353,12 @@ struct em28xx_fh {
         struct em28xx *dev;
         unsigned int  stream_on:1;      /* Locks streams */
         int           radio;
+
+        unsigned int                 width, height;
+        struct videobuf_queue        vb_vidq;
+        struct em28xx_fmt            *fmt;
+
+        enum v4l2_buf_type           type;
 };
 
 struct em28xx_ops {
@@ -351,8 +395,6 @@ int em28xx_colorlevels_set_default(struct em28xx *dev);
 int em28xx_capture_start(struct em28xx *dev, int start);
 int em28xx_outfmt_set_yuv422(struct em28xx *dev);
 int em28xx_resolution_set(struct em28xx *dev);
-int em28xx_init_isoc(struct em28xx *dev);
-void em28xx_uninit_isoc(struct em28xx *dev);
 int em28xx_set_alternate(struct em28xx *dev);
 
 /* Provided by em28xx-video.c */