android_kernel_xiaomi_sm8350/drivers/media/video/saa7134/saa6752hs.c
Hans Verkuil 3bcc95760c V4L/DVB (6321): Remove obsolete VIDIOC_S/G_MPEGCOMP ioctls
Remove the obsolete VIDIOC_G_MPEGCOMP and VIDIOC_S_MPEGCOMP ioctls from
the V4L2 API as per the removal schedule (October 2007).

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
2007-10-22 12:01:30 -02:00

733 lines
18 KiB
C

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/i2c.h>
#include <linux/types.h>
#include <linux/videodev2.h>
#include <media/v4l2-common.h>
#include <linux/init.h>
#include <linux/crc32.h>
#define MPEG_VIDEO_TARGET_BITRATE_MAX 27000
#define MPEG_VIDEO_MAX_BITRATE_MAX 27000
#define MPEG_TOTAL_TARGET_BITRATE_MAX 27000
#define MPEG_PID_MAX ((1 << 14) - 1)
/* Addresses to scan */
static unsigned short normal_i2c[] = {0x20, I2C_CLIENT_END};
I2C_CLIENT_INSMOD;
MODULE_DESCRIPTION("device driver for saa6752hs MPEG2 encoder");
MODULE_AUTHOR("Andrew de Quincey");
MODULE_LICENSE("GPL");
static struct i2c_driver driver;
static struct i2c_client client_template;
enum saa6752hs_videoformat {
SAA6752HS_VF_D1 = 0, /* standard D1 video format: 720x576 */
SAA6752HS_VF_2_3_D1 = 1,/* 2/3D1 video format: 480x576 */
SAA6752HS_VF_1_2_D1 = 2,/* 1/2D1 video format: 352x576 */
SAA6752HS_VF_SIF = 3, /* SIF video format: 352x288 */
SAA6752HS_VF_UNKNOWN,
};
struct saa6752hs_mpeg_params {
/* transport streams */
__u16 ts_pid_pmt;
__u16 ts_pid_audio;
__u16 ts_pid_video;
__u16 ts_pid_pcr;
/* audio */
enum v4l2_mpeg_audio_l2_bitrate au_l2_bitrate;
/* video */
enum v4l2_mpeg_video_aspect vi_aspect;
enum v4l2_mpeg_video_bitrate_mode vi_bitrate_mode;
__u32 vi_bitrate;
__u32 vi_bitrate_peak;
};
static const struct v4l2_format v4l2_format_table[] =
{
[SAA6752HS_VF_D1] =
{ .fmt = { .pix = { .width = 720, .height = 576 }}},
[SAA6752HS_VF_2_3_D1] =
{ .fmt = { .pix = { .width = 480, .height = 576 }}},
[SAA6752HS_VF_1_2_D1] =
{ .fmt = { .pix = { .width = 352, .height = 576 }}},
[SAA6752HS_VF_SIF] =
{ .fmt = { .pix = { .width = 352, .height = 288 }}},
[SAA6752HS_VF_UNKNOWN] =
{ .fmt = { .pix = { .width = 0, .height = 0}}},
};
struct saa6752hs_state {
struct i2c_client client;
struct saa6752hs_mpeg_params params;
enum saa6752hs_videoformat video_format;
v4l2_std_id standard;
};
enum saa6752hs_command {
SAA6752HS_COMMAND_RESET = 0,
SAA6752HS_COMMAND_STOP = 1,
SAA6752HS_COMMAND_START = 2,
SAA6752HS_COMMAND_PAUSE = 3,
SAA6752HS_COMMAND_RECONFIGURE = 4,
SAA6752HS_COMMAND_SLEEP = 5,
SAA6752HS_COMMAND_RECONFIGURE_FORCE = 6,
SAA6752HS_COMMAND_MAX
};
/* ---------------------------------------------------------------------- */
static u8 PAT[] = {
0xc2, /* i2c register */
0x00, /* table number for encoder */
0x47, /* sync */
0x40, 0x00, /* transport_error_indicator(0), payload_unit_start(1), transport_priority(0), pid(0) */
0x10, /* transport_scrambling_control(00), adaptation_field_control(01), continuity_counter(0) */
0x00, /* PSI pointer to start of table */
0x00, /* tid(0) */
0xb0, 0x0d, /* section_syntax_indicator(1), section_length(13) */
0x00, 0x01, /* transport_stream_id(1) */
0xc1, /* version_number(0), current_next_indicator(1) */
0x00, 0x00, /* section_number(0), last_section_number(0) */
0x00, 0x01, /* program_number(1) */
0xe0, 0x00, /* PMT PID */
0x00, 0x00, 0x00, 0x00 /* CRC32 */
};
static u8 PMT[] = {
0xc2, /* i2c register */
0x01, /* table number for encoder */
0x47, /* sync */
0x40, 0x00, /* transport_error_indicator(0), payload_unit_start(1), transport_priority(0), pid */
0x10, /* transport_scrambling_control(00), adaptation_field_control(01), continuity_counter(0) */
0x00, /* PSI pointer to start of table */
0x02, /* tid(2) */
0xb0, 0x17, /* section_syntax_indicator(1), section_length(23) */
0x00, 0x01, /* program_number(1) */
0xc1, /* version_number(0), current_next_indicator(1) */
0x00, 0x00, /* section_number(0), last_section_number(0) */
0xe0, 0x00, /* PCR_PID */
0xf0, 0x00, /* program_info_length(0) */
0x02, 0xe0, 0x00, 0xf0, 0x00, /* video stream type(2), pid */
0x04, 0xe0, 0x00, 0xf0, 0x00, /* audio stream type(4), pid */
0x00, 0x00, 0x00, 0x00 /* CRC32 */
};
static struct saa6752hs_mpeg_params param_defaults =
{
.ts_pid_pmt = 16,
.ts_pid_video = 260,
.ts_pid_audio = 256,
.ts_pid_pcr = 259,
.vi_aspect = V4L2_MPEG_VIDEO_ASPECT_4x3,
.vi_bitrate = 4000,
.vi_bitrate_peak = 6000,
.vi_bitrate_mode = V4L2_MPEG_VIDEO_BITRATE_MODE_VBR,
.au_l2_bitrate = V4L2_MPEG_AUDIO_L2_BITRATE_256K,
};
/* ---------------------------------------------------------------------- */
static int saa6752hs_chip_command(struct i2c_client* client,
enum saa6752hs_command command)
{
unsigned char buf[3];
unsigned long timeout;
int status = 0;
/* execute the command */
switch(command) {
case SAA6752HS_COMMAND_RESET:
buf[0] = 0x00;
break;
case SAA6752HS_COMMAND_STOP:
buf[0] = 0x03;
break;
case SAA6752HS_COMMAND_START:
buf[0] = 0x02;
break;
case SAA6752HS_COMMAND_PAUSE:
buf[0] = 0x04;
break;
case SAA6752HS_COMMAND_RECONFIGURE:
buf[0] = 0x05;
break;
case SAA6752HS_COMMAND_SLEEP:
buf[0] = 0x06;
break;
case SAA6752HS_COMMAND_RECONFIGURE_FORCE:
buf[0] = 0x07;
break;
default:
return -EINVAL;
}
/* set it and wait for it to be so */
i2c_master_send(client, buf, 1);
timeout = jiffies + HZ * 3;
for (;;) {
/* get the current status */
buf[0] = 0x10;
i2c_master_send(client, buf, 1);
i2c_master_recv(client, buf, 1);
if (!(buf[0] & 0x20))
break;
if (time_after(jiffies,timeout)) {
status = -ETIMEDOUT;
break;
}
msleep(10);
}
/* delay a bit to let encoder settle */
msleep(50);
return status;
}
static int saa6752hs_set_bitrate(struct i2c_client* client,
struct saa6752hs_mpeg_params* params)
{
u8 buf[3];
int tot_bitrate;
/* set the bitrate mode */
buf[0] = 0x71;
buf[1] = (params->vi_bitrate_mode == V4L2_MPEG_VIDEO_BITRATE_MODE_VBR) ? 0 : 1;
i2c_master_send(client, buf, 2);
/* set the video bitrate */
if (params->vi_bitrate_mode == V4L2_MPEG_VIDEO_BITRATE_MODE_VBR) {
/* set the target bitrate */
buf[0] = 0x80;
buf[1] = params->vi_bitrate >> 8;
buf[2] = params->vi_bitrate & 0xff;
i2c_master_send(client, buf, 3);
/* set the max bitrate */
buf[0] = 0x81;
buf[1] = params->vi_bitrate_peak >> 8;
buf[2] = params->vi_bitrate_peak & 0xff;
i2c_master_send(client, buf, 3);
tot_bitrate = params->vi_bitrate_peak;
} else {
/* set the target bitrate (no max bitrate for CBR) */
buf[0] = 0x81;
buf[1] = params->vi_bitrate >> 8;
buf[2] = params->vi_bitrate & 0xff;
i2c_master_send(client, buf, 3);
tot_bitrate = params->vi_bitrate;
}
/* set the audio bitrate */
buf[0] = 0x94;
buf[1] = (V4L2_MPEG_AUDIO_L2_BITRATE_256K == params->au_l2_bitrate) ? 0 : 1;
i2c_master_send(client, buf, 2);
tot_bitrate += (V4L2_MPEG_AUDIO_L2_BITRATE_256K == params->au_l2_bitrate) ? 256 : 384;
/* Note: the total max bitrate is determined by adding the video and audio
bitrates together and also adding an extra 768kbit/s to stay on the
safe side. If more control should be required, then an extra MPEG control
should be added. */
tot_bitrate += 768;
if (tot_bitrate > MPEG_TOTAL_TARGET_BITRATE_MAX)
tot_bitrate = MPEG_TOTAL_TARGET_BITRATE_MAX;
/* set the total bitrate */
buf[0] = 0xb1;
buf[1] = tot_bitrate >> 8;
buf[2] = tot_bitrate & 0xff;
i2c_master_send(client, buf, 3);
return 0;
}
static void saa6752hs_set_subsampling(struct i2c_client* client,
struct v4l2_format* f)
{
struct saa6752hs_state *h = i2c_get_clientdata(client);
int dist_352, dist_480, dist_720;
/*
FIXME: translate and round width/height into EMPRESS
subsample type:
type | PAL | NTSC
---------------------------
SIF | 352x288 | 352x240
1/2 D1 | 352x576 | 352x480
2/3 D1 | 480x576 | 480x480
D1 | 720x576 | 720x480
*/
dist_352 = abs(f->fmt.pix.width - 352);
dist_480 = abs(f->fmt.pix.width - 480);
dist_720 = abs(f->fmt.pix.width - 720);
if (dist_720 < dist_480) {
f->fmt.pix.width = 720;
f->fmt.pix.height = 576;
h->video_format = SAA6752HS_VF_D1;
}
else if (dist_480 < dist_352) {
f->fmt.pix.width = 480;
f->fmt.pix.height = 576;
h->video_format = SAA6752HS_VF_2_3_D1;
}
else {
f->fmt.pix.width = 352;
if (abs(f->fmt.pix.height - 576) <
abs(f->fmt.pix.height - 288)) {
f->fmt.pix.height = 576;
h->video_format = SAA6752HS_VF_1_2_D1;
}
else {
f->fmt.pix.height = 288;
h->video_format = SAA6752HS_VF_SIF;
}
}
}
static int handle_ctrl(struct saa6752hs_mpeg_params *params,
struct v4l2_ext_control *ctrl, unsigned int cmd)
{
int old = 0, new;
int set = (cmd == VIDIOC_S_EXT_CTRLS);
new = ctrl->value;
switch (ctrl->id) {
case V4L2_CID_MPEG_STREAM_TYPE:
old = V4L2_MPEG_STREAM_TYPE_MPEG2_TS;
if (set && new != old)
return -ERANGE;
new = old;
break;
case V4L2_CID_MPEG_STREAM_PID_PMT:
old = params->ts_pid_pmt;
if (set && new > MPEG_PID_MAX)
return -ERANGE;
if (new > MPEG_PID_MAX)
new = MPEG_PID_MAX;
params->ts_pid_pmt = new;
break;
case V4L2_CID_MPEG_STREAM_PID_AUDIO:
old = params->ts_pid_audio;
if (set && new > MPEG_PID_MAX)
return -ERANGE;
if (new > MPEG_PID_MAX)
new = MPEG_PID_MAX;
params->ts_pid_audio = new;
break;
case V4L2_CID_MPEG_STREAM_PID_VIDEO:
old = params->ts_pid_video;
if (set && new > MPEG_PID_MAX)
return -ERANGE;
if (new > MPEG_PID_MAX)
new = MPEG_PID_MAX;
params->ts_pid_video = new;
break;
case V4L2_CID_MPEG_STREAM_PID_PCR:
old = params->ts_pid_pcr;
if (set && new > MPEG_PID_MAX)
return -ERANGE;
if (new > MPEG_PID_MAX)
new = MPEG_PID_MAX;
params->ts_pid_pcr = new;
break;
case V4L2_CID_MPEG_AUDIO_ENCODING:
old = V4L2_MPEG_AUDIO_ENCODING_LAYER_2;
if (set && new != old)
return -ERANGE;
new = old;
break;
case V4L2_CID_MPEG_AUDIO_L2_BITRATE:
old = params->au_l2_bitrate;
if (set && new != V4L2_MPEG_AUDIO_L2_BITRATE_256K &&
new != V4L2_MPEG_AUDIO_L2_BITRATE_384K)
return -ERANGE;
if (new <= V4L2_MPEG_AUDIO_L2_BITRATE_256K)
new = V4L2_MPEG_AUDIO_L2_BITRATE_256K;
else
new = V4L2_MPEG_AUDIO_L2_BITRATE_384K;
params->au_l2_bitrate = new;
break;
case V4L2_CID_MPEG_AUDIO_SAMPLING_FREQ:
old = V4L2_MPEG_AUDIO_SAMPLING_FREQ_48000;
if (set && new != old)
return -ERANGE;
new = old;
break;
case V4L2_CID_MPEG_VIDEO_ENCODING:
old = V4L2_MPEG_VIDEO_ENCODING_MPEG_2;
if (set && new != old)
return -ERANGE;
new = old;
break;
case V4L2_CID_MPEG_VIDEO_ASPECT:
old = params->vi_aspect;
if (set && new != V4L2_MPEG_VIDEO_ASPECT_16x9 &&
new != V4L2_MPEG_VIDEO_ASPECT_4x3)
return -ERANGE;
if (new != V4L2_MPEG_VIDEO_ASPECT_16x9)
new = V4L2_MPEG_VIDEO_ASPECT_4x3;
params->vi_aspect = new;
break;
case V4L2_CID_MPEG_VIDEO_BITRATE:
old = params->vi_bitrate * 1000;
new = 1000 * (new / 1000);
if (set && new > MPEG_VIDEO_TARGET_BITRATE_MAX * 1000)
return -ERANGE;
if (new > MPEG_VIDEO_TARGET_BITRATE_MAX * 1000)
new = MPEG_VIDEO_TARGET_BITRATE_MAX * 1000;
params->vi_bitrate = new / 1000;
break;
case V4L2_CID_MPEG_VIDEO_BITRATE_PEAK:
old = params->vi_bitrate_peak * 1000;
new = 1000 * (new / 1000);
if (set && new > MPEG_VIDEO_TARGET_BITRATE_MAX * 1000)
return -ERANGE;
if (new > MPEG_VIDEO_TARGET_BITRATE_MAX * 1000)
new = MPEG_VIDEO_TARGET_BITRATE_MAX * 1000;
params->vi_bitrate_peak = new / 1000;
break;
case V4L2_CID_MPEG_VIDEO_BITRATE_MODE:
old = params->vi_bitrate_mode;
params->vi_bitrate_mode = new;
break;
default:
return -EINVAL;
}
if (cmd == VIDIOC_G_EXT_CTRLS)
ctrl->value = old;
else
ctrl->value = new;
return 0;
}
static int saa6752hs_init(struct i2c_client* client)
{
unsigned char buf[9], buf2[4];
struct saa6752hs_state *h;
u32 crc;
unsigned char localPAT[256];
unsigned char localPMT[256];
h = i2c_get_clientdata(client);
/* Set video format - must be done first as it resets other settings */
buf[0] = 0x41;
buf[1] = h->video_format;
i2c_master_send(client, buf, 2);
/* Set number of lines in input signal */
buf[0] = 0x40;
buf[1] = 0x00;
if (h->standard & V4L2_STD_525_60)
buf[1] = 0x01;
i2c_master_send(client, buf, 2);
/* set bitrate */
saa6752hs_set_bitrate(client, &h->params);
/* Set GOP structure {3, 13} */
buf[0] = 0x72;
buf[1] = 0x03;
buf[2] = 0x0D;
i2c_master_send(client,buf,3);
/* Set minimum Q-scale {4} */
buf[0] = 0x82;
buf[1] = 0x04;
i2c_master_send(client,buf,2);
/* Set maximum Q-scale {12} */
buf[0] = 0x83;
buf[1] = 0x0C;
i2c_master_send(client,buf,2);
/* Set Output Protocol */
buf[0] = 0xD0;
buf[1] = 0x81;
i2c_master_send(client,buf,2);
/* Set video output stream format {TS} */
buf[0] = 0xB0;
buf[1] = 0x05;
i2c_master_send(client,buf,2);
/* compute PAT */
memcpy(localPAT, PAT, sizeof(PAT));
localPAT[17] = 0xe0 | ((h->params.ts_pid_pmt >> 8) & 0x0f);
localPAT[18] = h->params.ts_pid_pmt & 0xff;
crc = crc32_be(~0, &localPAT[7], sizeof(PAT) - 7 - 4);
localPAT[sizeof(PAT) - 4] = (crc >> 24) & 0xFF;
localPAT[sizeof(PAT) - 3] = (crc >> 16) & 0xFF;
localPAT[sizeof(PAT) - 2] = (crc >> 8) & 0xFF;
localPAT[sizeof(PAT) - 1] = crc & 0xFF;
/* compute PMT */
memcpy(localPMT, PMT, sizeof(PMT));
localPMT[3] = 0x40 | ((h->params.ts_pid_pmt >> 8) & 0x0f);
localPMT[4] = h->params.ts_pid_pmt & 0xff;
localPMT[15] = 0xE0 | ((h->params.ts_pid_pcr >> 8) & 0x0F);
localPMT[16] = h->params.ts_pid_pcr & 0xFF;
localPMT[20] = 0xE0 | ((h->params.ts_pid_video >> 8) & 0x0F);
localPMT[21] = h->params.ts_pid_video & 0xFF;
localPMT[25] = 0xE0 | ((h->params.ts_pid_audio >> 8) & 0x0F);
localPMT[26] = h->params.ts_pid_audio & 0xFF;
crc = crc32_be(~0, &localPMT[7], sizeof(PMT) - 7 - 4);
localPMT[sizeof(PMT) - 4] = (crc >> 24) & 0xFF;
localPMT[sizeof(PMT) - 3] = (crc >> 16) & 0xFF;
localPMT[sizeof(PMT) - 2] = (crc >> 8) & 0xFF;
localPMT[sizeof(PMT) - 1] = crc & 0xFF;
/* Set Audio PID */
buf[0] = 0xC1;
buf[1] = (h->params.ts_pid_audio >> 8) & 0xFF;
buf[2] = h->params.ts_pid_audio & 0xFF;
i2c_master_send(client,buf,3);
/* Set Video PID */
buf[0] = 0xC0;
buf[1] = (h->params.ts_pid_video >> 8) & 0xFF;
buf[2] = h->params.ts_pid_video & 0xFF;
i2c_master_send(client,buf,3);
/* Set PCR PID */
buf[0] = 0xC4;
buf[1] = (h->params.ts_pid_pcr >> 8) & 0xFF;
buf[2] = h->params.ts_pid_pcr & 0xFF;
i2c_master_send(client,buf,3);
/* Send SI tables */
i2c_master_send(client,localPAT,sizeof(PAT));
i2c_master_send(client,localPMT,sizeof(PMT));
/* mute then unmute audio. This removes buzzing artefacts */
buf[0] = 0xa4;
buf[1] = 1;
i2c_master_send(client, buf, 2);
buf[1] = 0;
i2c_master_send(client, buf, 2);
/* start it going */
saa6752hs_chip_command(client, SAA6752HS_COMMAND_START);
/* readout current state */
buf[0] = 0xE1;
buf[1] = 0xA7;
buf[2] = 0xFE;
buf[3] = 0x82;
buf[4] = 0xB0;
i2c_master_send(client, buf, 5);
i2c_master_recv(client, buf2, 4);
/* change aspect ratio */
buf[0] = 0xE0;
buf[1] = 0xA7;
buf[2] = 0xFE;
buf[3] = 0x82;
buf[4] = 0xB0;
buf[5] = buf2[0];
switch(h->params.vi_aspect) {
case V4L2_MPEG_VIDEO_ASPECT_16x9:
buf[6] = buf2[1] | 0x40;
break;
case V4L2_MPEG_VIDEO_ASPECT_4x3:
default:
buf[6] = buf2[1] & 0xBF;
break;
break;
}
buf[7] = buf2[2];
buf[8] = buf2[3];
i2c_master_send(client, buf, 9);
return 0;
}
static int saa6752hs_attach(struct i2c_adapter *adap, int addr, int kind)
{
struct saa6752hs_state *h;
if (NULL == (h = kzalloc(sizeof(*h), GFP_KERNEL)))
return -ENOMEM;
h->client = client_template;
h->params = param_defaults;
h->client.adapter = adap;
h->client.addr = addr;
/* Assume 625 input lines */
h->standard = 0;
i2c_set_clientdata(&h->client, h);
i2c_attach_client(&h->client);
v4l_info(&h->client,"saa6752hs: chip found @ 0x%x\n", addr<<1);
return 0;
}
static int saa6752hs_probe(struct i2c_adapter *adap)
{
if (adap->class & I2C_CLASS_TV_ANALOG)
return i2c_probe(adap, &addr_data, saa6752hs_attach);
return 0;
}
static int saa6752hs_detach(struct i2c_client *client)
{
struct saa6752hs_state *h;
h = i2c_get_clientdata(client);
i2c_detach_client(client);
kfree(h);
return 0;
}
static int
saa6752hs_command(struct i2c_client *client, unsigned int cmd, void *arg)
{
struct saa6752hs_state *h = i2c_get_clientdata(client);
struct v4l2_ext_controls *ctrls = arg;
struct saa6752hs_mpeg_params params;
int err = 0;
int i;
switch (cmd) {
case VIDIOC_S_EXT_CTRLS:
if (ctrls->ctrl_class != V4L2_CTRL_CLASS_MPEG)
return -EINVAL;
if (ctrls->count == 0) {
/* apply settings and start encoder */
saa6752hs_init(client);
break;
}
/* fall through */
case VIDIOC_TRY_EXT_CTRLS:
case VIDIOC_G_EXT_CTRLS:
if (ctrls->ctrl_class != V4L2_CTRL_CLASS_MPEG)
return -EINVAL;
params = h->params;
for (i = 0; i < ctrls->count; i++) {
if ((err = handle_ctrl(&params, ctrls->controls + i, cmd))) {
ctrls->error_idx = i;
return err;
}
}
h->params = params;
break;
case VIDIOC_G_FMT:
{
struct v4l2_format *f = arg;
if (h->video_format == SAA6752HS_VF_UNKNOWN)
h->video_format = SAA6752HS_VF_D1;
f->fmt.pix.width =
v4l2_format_table[h->video_format].fmt.pix.width;
f->fmt.pix.height =
v4l2_format_table[h->video_format].fmt.pix.height;
break ;
}
case VIDIOC_S_FMT:
{
struct v4l2_format *f = arg;
saa6752hs_set_subsampling(client, f);
break;
}
case VIDIOC_S_STD:
h->standard = *((v4l2_std_id *) arg);
break;
default:
/* nothing */
break;
}
return err;
}
/* ----------------------------------------------------------------------- */
static struct i2c_driver driver = {
.driver = {
.name = "saa6752hs",
},
.id = I2C_DRIVERID_SAA6752HS,
.attach_adapter = saa6752hs_probe,
.detach_client = saa6752hs_detach,
.command = saa6752hs_command,
};
static struct i2c_client client_template =
{
.name = "saa6752hs",
.driver = &driver,
};
static int __init saa6752hs_init_module(void)
{
return i2c_add_driver(&driver);
}
static void __exit saa6752hs_cleanup_module(void)
{
i2c_del_driver(&driver);
}
module_init(saa6752hs_init_module);
module_exit(saa6752hs_cleanup_module);
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* ---------------------------------------------------------------------------
* Local variables:
* c-basic-offset: 8
* End:
*/