This makes transmission more reliable and the code much cleaner.
Signed-off-by: Sean Young <s...@mess.org>
---
drivers/media/rc/serial_ir.c | 264 ++++++++++---------------------------------
1 file changed, 59 insertions(+), 205 deletions(-)
diff --git a/drivers/media/rc/serial_ir.c b/drivers/media/rc/serial_ir.c
index 378ae09..1ae8425 100644
--- a/drivers/media/rc/serial_ir.c
+++ b/drivers/media/rc/serial_ir.c
@@ -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 <st...@daviesfam.org> July 2001
- */
-
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
@@ -66,8 +43,8 @@ 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;
};
@@ -89,11 +66,11 @@ 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[] = {
@@ -139,8 +116,6 @@ 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] = {
@@ -168,51 +143,11 @@ 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.saikko...@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)
{
@@ -264,81 +199,21 @@ static void safe_udelay(unsigned long usecs)
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,
+static void 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;
-}
-#else /* ! USE_RDTSC */
-static int init_timing_params(unsigned int new_duty_cycle,
- unsigned int new_freq)
-{
-/*
- * 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;
+ 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);
}
-#endif /* USE_RDTSC */
-
-
-/* return value: space length delta */
-static long send_pulse_irdeo(unsigned long length)
+static void send_pulse_irdeo(unsigned int length, ktime_t target)
{
- long rawbits, ret;
+ long rawbits;
int i;
unsigned char output;
unsigned char chunk, shifted;
@@ -367,84 +242,53 @@ 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;
-
- length <<= 8;
+ 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;
- 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
@@ -748,7 +592,8 @@ 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);
@@ -756,11 +601,18 @@ 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 > 0)
+ safe_udelay(delta);
}
off();
spin_unlock_irqrestore(&hardware[type].lock, flags);
@@ -769,7 +621,8 @@ 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)
@@ -777,7 +630,8 @@ 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,
--
2.7.4
--
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