[media] lirc_serial: use precision ktime rather than guessing
This makes transmission more reliable and the code much cleaner. Signed-off-by: Sean Young <sean@mess.org> Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Sean Young
Mauro Carvalho Chehab
parent
b66db53f8d
commit
0a84763484
|
|
@ -21,29 +21,6 @@
|
|||
* GNU General Public License for more details.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Steve's changes to improve transmission fidelity:
|
||||
* - for systems with the rdtsc instruction and the clock counter, a
|
||||
* send_pule that times the pulses directly using the counter.
|
||||
* This means that the IR_SERIAL_TRANSMITTER_LATENCY fudge is
|
||||
* not needed. Measurement shows very stable waveform, even where
|
||||
* PCI activity slows the access to the UART, which trips up other
|
||||
* versions.
|
||||
* - For other system, non-integer-microsecond pulse/space lengths,
|
||||
* done using fixed point binary. So, much more accurate carrier
|
||||
* frequency.
|
||||
* - fine tuned transmitter latency, taking advantage of fractional
|
||||
* microseconds in previous change
|
||||
* - Fixed bug in the way transmitter latency was accounted for by
|
||||
* tuning the pulse lengths down - the send_pulse routine ignored
|
||||
* this overhead as it timed the overall pulse length - so the
|
||||
* pulse frequency was right but overall pulse length was too
|
||||
* long. Fixed by accounting for latency on each pulse/space
|
||||
* iteration.
|
||||
*
|
||||
* Steve Davies <steve@daviesfam.org> July 2001
|
||||
*/
|
||||
|
||||
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
||||
|
||||
#include <linux/module.h>
|
||||
|
|
@ -64,8 +41,8 @@ struct serial_ir_hw {
|
|||
u8 off;
|
||||
unsigned set_send_carrier:1;
|
||||
unsigned set_duty_cycle:1;
|
||||
long (*send_pulse)(unsigned long length);
|
||||
void (*send_space)(long length);
|
||||
void (*send_pulse)(unsigned int length, ktime_t edge);
|
||||
void (*send_space)(void);
|
||||
spinlock_t lock;
|
||||
};
|
||||
|
||||
|
|
@ -87,11 +64,11 @@ static int sense = -1; /* -1 = auto, 0 = active high, 1 = active low */
|
|||
static bool txsense; /* 0 = active high, 1 = active low */
|
||||
|
||||
/* forward declarations */
|
||||
static long send_pulse_irdeo(unsigned long length);
|
||||
static void send_space_irdeo(long length);
|
||||
static void send_pulse_irdeo(unsigned int length, ktime_t edge);
|
||||
static void send_space_irdeo(void);
|
||||
#ifdef CONFIG_IR_SERIAL_TRANSMITTER
|
||||
static long send_pulse_homebrew(unsigned long length);
|
||||
static void send_space_homebrew(long length);
|
||||
static void send_pulse_homebrew(unsigned int length, ktime_t edge);
|
||||
static void send_space_homebrew(void);
|
||||
#endif
|
||||
|
||||
static struct serial_ir_hw hardware[] = {
|
||||
|
|
@ -137,8 +114,6 @@ static struct serial_ir_hw hardware[] = {
|
|||
.signal_pin_change = UART_MSR_DDCD,
|
||||
.on = 0,
|
||||
.off = (UART_MCR_RTS | UART_MCR_DTR | UART_MCR_OUT2),
|
||||
.send_pulse = NULL,
|
||||
.send_space = NULL,
|
||||
},
|
||||
|
||||
[IR_IGOR] = {
|
||||
|
|
@ -166,51 +141,11 @@ struct serial_ir {
|
|||
unsigned int freq;
|
||||
unsigned int duty_cycle;
|
||||
|
||||
unsigned long period;
|
||||
unsigned long pulse_width, space_width;
|
||||
unsigned int pulse_width, space_width;
|
||||
};
|
||||
|
||||
static struct serial_ir serial_ir;
|
||||
|
||||
#if defined(__i386__)
|
||||
/*
|
||||
* From:
|
||||
* Linux I/O port programming mini-HOWTO
|
||||
* Author: Riku Saikkonen <Riku.Saikkonen@hut.fi>
|
||||
* v, 28 December 1997
|
||||
*
|
||||
* [...]
|
||||
* Actually, a port I/O instruction on most ports in the 0-0x3ff range
|
||||
* takes almost exactly 1 microsecond, so if you're, for example, using
|
||||
* the parallel port directly, just do additional inb()s from that port
|
||||
* to delay.
|
||||
* [...]
|
||||
*/
|
||||
/* transmitter latency 1.5625us 0x1.90 - this figure arrived at from
|
||||
* comment above plus trimming to match actual measured frequency.
|
||||
* This will be sensitive to cpu speed, though hopefully most of the 1.5us
|
||||
* is spent in the uart access. Still - for reference test machine was a
|
||||
* 1.13GHz Athlon system - Steve
|
||||
*/
|
||||
|
||||
/*
|
||||
* changed from 400 to 450 as this works better on slower machines;
|
||||
* faster machines will use the rdtsc code anyway
|
||||
*/
|
||||
#define IR_SERIAL_TRANSMITTER_LATENCY 450
|
||||
|
||||
#else
|
||||
|
||||
/* does anybody have information on other platforms ? */
|
||||
/* 256 = 1<<8 */
|
||||
#define IR_SERIAL_TRANSMITTER_LATENCY 256
|
||||
|
||||
#endif /* __i386__ */
|
||||
/*
|
||||
* FIXME: should we be using hrtimers instead of this
|
||||
* IR_SERIAL_TRANSMITTER_LATENCY nonsense?
|
||||
*/
|
||||
|
||||
/* fetch serial input packet (1 byte) from register offset */
|
||||
static u8 sinp(int offset)
|
||||
{
|
||||
|
|
@ -247,96 +182,21 @@ static void off(void)
|
|||
soutp(UART_MCR, hardware[type].off);
|
||||
}
|
||||
|
||||
#ifndef MAX_UDELAY_MS
|
||||
#define MAX_UDELAY_US 5000
|
||||
#else
|
||||
#define MAX_UDELAY_US (MAX_UDELAY_MS*1000)
|
||||
#endif
|
||||
|
||||
static void safe_udelay(unsigned long usecs)
|
||||
static void init_timing_params(unsigned int new_duty_cycle,
|
||||
unsigned int new_freq)
|
||||
{
|
||||
while (usecs > MAX_UDELAY_US) {
|
||||
udelay(MAX_UDELAY_US);
|
||||
usecs -= MAX_UDELAY_US;
|
||||
}
|
||||
udelay(usecs);
|
||||
}
|
||||
|
||||
#ifdef USE_RDTSC
|
||||
/*
|
||||
* This is an overflow/precision juggle, complicated in that we can't
|
||||
* do long long divide in the kernel
|
||||
*/
|
||||
|
||||
/*
|
||||
* When we use the rdtsc instruction to measure clocks, we keep the
|
||||
* pulse and space widths as clock cycles. As this is CPU speed
|
||||
* dependent, the widths must be calculated in init_port and ioctl
|
||||
* time
|
||||
*/
|
||||
|
||||
static int init_timing_params(unsigned int new_duty_cycle,
|
||||
unsigned int new_freq)
|
||||
{
|
||||
__u64 loops_per_sec, work;
|
||||
|
||||
serial_ir.duty_cycle = new_duty_cycle;
|
||||
serial_ir.freq = new_freq;
|
||||
|
||||
loops_per_sec = __this_cpu_read(cpu.info.loops_per_jiffy);
|
||||
loops_per_sec *= HZ;
|
||||
|
||||
/* How many clocks in a microsecond?, avoiding long long divide */
|
||||
work = loops_per_sec;
|
||||
work *= 4295; /* 4295 = 2^32 / 1e6 */
|
||||
|
||||
/*
|
||||
* Carrier period in clocks, approach good up to 32GHz clock,
|
||||
* gets carrier frequency within 8Hz
|
||||
*/
|
||||
serial_ir.period = loops_per_sec >> 3;
|
||||
serial_ir.pperiod /= (freq >> 3);
|
||||
|
||||
/* Derive pulse and space from the period */
|
||||
serial_ir.ppulse_width = serial_ir.period * serial.ir.duty_cycle / 100;
|
||||
serial_ir.pspace_width = serial_ir.period - serial_ir.pulse_width;
|
||||
pr_debug("in init_timing_params, freq=%d, duty_cycle=%d, clk/jiffy=%ld, pulse=%ld, space=%ld, conv_us_to_clocks=%ld\n",
|
||||
freq, duty_cycle, __this_cpu_read(cpu_info.loops_per_jiffy),
|
||||
pulse_width, space_width, conv_us_to_clocks);
|
||||
return 0;
|
||||
serial_ir.pulse_width = DIV_ROUND_CLOSEST(
|
||||
new_duty_cycle * NSEC_PER_SEC, new_freq * 100l);
|
||||
serial_ir.space_width = DIV_ROUND_CLOSEST(
|
||||
(100l - new_duty_cycle) * NSEC_PER_SEC, new_freq * 100l);
|
||||
}
|
||||
#else /* ! USE_RDTSC */
|
||||
static int init_timing_params(unsigned int new_duty_cycle,
|
||||
unsigned int new_freq)
|
||||
|
||||
static void send_pulse_irdeo(unsigned int length, ktime_t target)
|
||||
{
|
||||
/*
|
||||
* period, pulse/space width are kept with 8 binary places -
|
||||
* IE multiplied by 256.
|
||||
*/
|
||||
if (256 * 1000000L / new_freq * new_duty_cycle / 100 <=
|
||||
IR_SERIAL_TRANSMITTER_LATENCY)
|
||||
return -EINVAL;
|
||||
if (256 * 1000000L / new_freq * (100 - new_duty_cycle) / 100 <=
|
||||
IR_SERIAL_TRANSMITTER_LATENCY)
|
||||
return -EINVAL;
|
||||
serial_ir.duty_cycle = new_duty_cycle;
|
||||
serial_ir.freq = new_freq;
|
||||
serial_ir.period = 256 * 1000000L / serial_ir.freq;
|
||||
serial_ir.pulse_width = serial_ir.period * serial_ir.duty_cycle / 100;
|
||||
serial_ir.space_width = serial_ir.period - serial_ir.pulse_width;
|
||||
pr_debug("in init_timing_params, freq=%d pulse=%ld, space=%ld\n",
|
||||
serial_ir.freq, serial_ir.pulse_width,
|
||||
serial_ir.space_width);
|
||||
return 0;
|
||||
}
|
||||
#endif /* USE_RDTSC */
|
||||
|
||||
|
||||
/* return value: space length delta */
|
||||
|
||||
static long send_pulse_irdeo(unsigned long length)
|
||||
{
|
||||
long rawbits, ret;
|
||||
long rawbits;
|
||||
int i;
|
||||
unsigned char output;
|
||||
unsigned char chunk, shifted;
|
||||
|
|
@ -365,84 +225,53 @@ static long send_pulse_irdeo(unsigned long length)
|
|||
while (!(sinp(UART_LSR) & UART_LSR_TEMT))
|
||||
;
|
||||
}
|
||||
|
||||
if (i == 0)
|
||||
ret = (-rawbits) * 10000 / 1152;
|
||||
else
|
||||
ret = (3 - i) * 3 * 10000 / 1152 + (-rawbits) * 10000 / 1152;
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Version using udelay() */
|
||||
|
||||
/*
|
||||
* here we use fixed point arithmetic, with 8
|
||||
* fractional bits. that gets us within 0.1% or so of the right average
|
||||
* frequency, albeit with some jitter in pulse length - Steve
|
||||
*
|
||||
* This should use ndelay instead.
|
||||
*/
|
||||
|
||||
/* To match 8 fractional bits used for pulse/space length */
|
||||
|
||||
static void send_space_irdeo(long length)
|
||||
static void send_space_irdeo(void)
|
||||
{
|
||||
if (length <= 0)
|
||||
return;
|
||||
|
||||
safe_udelay(length);
|
||||
}
|
||||
|
||||
#ifdef CONFIG_IR_SERIAL_TRANSMITTER
|
||||
static long send_pulse_homebrew_softcarrier(unsigned long length)
|
||||
static void send_pulse_homebrew_softcarrier(unsigned int length, ktime_t edge)
|
||||
{
|
||||
int flag;
|
||||
unsigned long actual, target, d;
|
||||
ktime_t now, target = ktime_add_us(edge, length);
|
||||
/*
|
||||
* delta should never exceed 4 seconds and on m68k
|
||||
* ndelay(s64) does not compile; so use s32 rather than s64.
|
||||
*/
|
||||
s32 delta;
|
||||
|
||||
length <<= 8;
|
||||
|
||||
actual = 0; target = 0; flag = 0;
|
||||
while (actual < length) {
|
||||
if (flag) {
|
||||
off();
|
||||
target += serial_ir.space_width;
|
||||
} else {
|
||||
on();
|
||||
target += serial_ir.pulse_width;
|
||||
}
|
||||
d = (target - actual -
|
||||
IR_SERIAL_TRANSMITTER_LATENCY + 128) >> 8;
|
||||
/*
|
||||
* Note - we've checked in ioctl that the pulse/space
|
||||
* widths are big enough so that d is > 0
|
||||
*/
|
||||
udelay(d);
|
||||
actual += (d << 8) + IR_SERIAL_TRANSMITTER_LATENCY;
|
||||
flag = !flag;
|
||||
for (;;) {
|
||||
now = ktime_get();
|
||||
if (ktime_compare(now, target) >= 0)
|
||||
break;
|
||||
on();
|
||||
edge = ktime_add_ns(edge, serial_ir.pulse_width);
|
||||
delta = ktime_to_ns(ktime_sub(edge, now));
|
||||
if (delta > 0)
|
||||
ndelay(delta);
|
||||
now = ktime_get();
|
||||
off();
|
||||
if (ktime_compare(now, target) >= 0)
|
||||
break;
|
||||
edge = ktime_add_ns(edge, serial_ir.space_width);
|
||||
delta = ktime_to_ns(ktime_sub(edge, now));
|
||||
if (delta > 0)
|
||||
ndelay(delta);
|
||||
}
|
||||
return (actual-length) >> 8;
|
||||
}
|
||||
|
||||
static long send_pulse_homebrew(unsigned long length)
|
||||
static void send_pulse_homebrew(unsigned int length, ktime_t edge)
|
||||
{
|
||||
if (length <= 0)
|
||||
return 0;
|
||||
|
||||
if (softcarrier)
|
||||
return send_pulse_homebrew_softcarrier(length);
|
||||
|
||||
on();
|
||||
safe_udelay(length);
|
||||
return 0;
|
||||
send_pulse_homebrew_softcarrier(length, edge);
|
||||
else
|
||||
on();
|
||||
}
|
||||
|
||||
static void send_space_homebrew(long length)
|
||||
static void send_space_homebrew(void)
|
||||
{
|
||||
off();
|
||||
if (length <= 0)
|
||||
return;
|
||||
safe_udelay(length);
|
||||
}
|
||||
#endif
|
||||
|
||||
|
|
@ -746,7 +575,8 @@ static int serial_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
|
|||
unsigned int count)
|
||||
{
|
||||
unsigned long flags;
|
||||
long delta = 0;
|
||||
ktime_t edge;
|
||||
s64 delta;
|
||||
int i;
|
||||
|
||||
spin_lock_irqsave(&hardware[type].lock, flags);
|
||||
|
|
@ -754,11 +584,23 @@ static int serial_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
|
|||
/* DTR, RTS down */
|
||||
on();
|
||||
}
|
||||
|
||||
edge = ktime_get();
|
||||
for (i = 0; i < count; i++) {
|
||||
if (i%2)
|
||||
hardware[type].send_space(txbuf[i] - delta);
|
||||
hardware[type].send_space();
|
||||
else
|
||||
delta = hardware[type].send_pulse(txbuf[i]);
|
||||
hardware[type].send_pulse(txbuf[i], edge);
|
||||
|
||||
edge = ktime_add_us(edge, txbuf[i]);
|
||||
delta = ktime_us_delta(edge, ktime_get());
|
||||
if (delta > 25) {
|
||||
spin_unlock_irqrestore(&hardware[type].lock, flags);
|
||||
usleep_range(delta - 25, delta + 25);
|
||||
spin_lock_irqsave(&hardware[type].lock, flags);
|
||||
}
|
||||
else if (delta > 0)
|
||||
udelay(delta);
|
||||
}
|
||||
off();
|
||||
spin_unlock_irqrestore(&hardware[type].lock, flags);
|
||||
|
|
@ -767,7 +609,8 @@ static int serial_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
|
|||
|
||||
static int serial_ir_tx_duty_cycle(struct rc_dev *dev, u32 cycle)
|
||||
{
|
||||
return init_timing_params(cycle, serial_ir.freq);
|
||||
init_timing_params(cycle, serial_ir.freq);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int serial_ir_tx_carrier(struct rc_dev *dev, u32 carrier)
|
||||
|
|
@ -775,7 +618,8 @@ static int serial_ir_tx_carrier(struct rc_dev *dev, u32 carrier)
|
|||
if (carrier > 500000 || carrier < 20000)
|
||||
return -EINVAL;
|
||||
|
||||
return init_timing_params(serial_ir.duty_cycle, carrier);
|
||||
init_timing_params(serial_ir.duty_cycle, carrier);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int serial_ir_suspend(struct platform_device *dev,
|
||||
|
|
|
|||
Loading…
Reference in New Issue