Some frequencies freezing the board
zeekhuge opened this issue · comments
There are few sampling frequencies that I have found to freeze the board. Though other frequencies higher than that work well.
Initially, I did
echo 1 > scan_elements/in_voltage0_en
echo 100 > buffer/length
for each of them.
This is not that these frequencies never work, but mostly they don't
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 793000 > in_voltage0_sampling_frequency && dmesg | tail -n 3
[ 3715.476017] 125, 61, 61
[ 3715.478719] Requested sampling freqeuency 793000
[ 3715.483456] Available sampling freqeuency 793650
root@beaglebone:/sys/bus/iio/devices/iio:device0# cat /proc/interrupts | tail -n 12 && echo 1 > buffer/enable && sleep 100 && echo 0 > buffer/enable && cat /proc/interrupts | tail -n 12
189: 0 INTC 7 Level tps65217
198: 4250758 4a320000.intc 16 Edge remoteproc2
211: 0 INTC 71 Level 4802a000.i2c
IPI0: 0 CPU wakeup interrupts
IPI1: 0 Timer broadcast interrupts
IPI2: 0 Rescheduling interrupts
IPI3: 0 Function call interrupts
IPI4: 0 Single function call interrupts
IPI5: 0 CPU stop interrupts
IPI6: 0 IRQ work interrupts
IPI7: 0 completion interrupts
Err: 0
//Freezes here
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 800000 > in_voltage0_sampling_frequency && dmesg | tail -n 3
[ 199.314410] 123, 61, 61
[ 199.316897] Requested sampling freqeuency 800000
[ 199.321775] Available sampling freqeuency 800000
root@beaglebone:/sys/bus/iio/devices/iio:device0# cat /proc/interrupts | tail -n 12 && echo 1 > buffer/enable && sleep 100 && echo 0 > buffer/enable && cat /proc/interrupts | tail -n 12
189: 0 INTC 7 Level tps65217
198: 1 4a320000.intc 16 Edge remoteproc2
211: 0 INTC 71 Level 4802a000.i2c
IPI0: 0 CPU wakeup interrupts
IPI1: 0 Timer broadcast interrupts
IPI2: 0 Rescheduling interrupts
IPI3: 0 Function call interrupts
IPI4: 0 Single function call interrupts
IPI5: 0 CPU stop interrupts
IPI6: 0 IRQ work interrupts
IPI7: 0 completion interrupts
//Freezes here
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 850000 > in_voltage0_sampling_frequency | dmesg | tail -n 3
[ 848.576385] 115, 57, 57
[ 848.578873] Requested sampling freqeuency 850000
[ 848.583719] Available sampling freqeuency 854700
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 1 > buffer/enable
//Freezes here
Frequencies higher that work well
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 890000 > in_voltage0_sampling_frequency | dmesg | tail -n 3
[ 83.440654] 111, 53, 55
[ 83.443365] Requested sampling freqeuency 890000
[ 83.448093] Available sampling freqeuency 892857
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 1 > buffer/enable
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 0 > buffer/enable
- In this case, the board was responding a bit slower, but that was probably because of its high speed data transfer
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 900000 > in_voltage0_sampling_frequency | dmesg | tail -n 3
[ 134.428058] 109, 53, 55
[ 134.430546] Requested sampling freqeuency 900000
[ 134.435417] Available sampling freqeuency 900900
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 1 > buffer/enable
root@beaglebone:/sys/bus/iio/devices/iio:device0#
root@beaglebone:/sys/bus/iio/devices/iio:device0# echo 0 > buffer/enable
Interesting !
To get the source of the bug, first I tested the PRU code, using single step mode described here and everything was fine there.
Then I found that there is something wrong with the callback method in the beaglescope_driver.c
callback -
static void beaglescope_driver_cb(struct rpmsg_channel *rpdev, void *data,
int len, void *priv, u32 src)
{
struct beaglescope_state *st;
struct iio_dev *indio_dev;
int count;
indio_dev = dev_get_drvdata(&rpdev->dev);
st = iio_priv(indio_dev);
if (get_beaglescope_read_mode(st) == RAW_READ){
log_debug("callback - raw mode");
st->raw_data=*((u32 *)data);
st->got_raw = 1;
wake_up_interruptible(&st->wait_list);
}else{
for (count =0; count < len; count++) {
iio_push_to_buffers(indio_dev, &((u8 *)data)[count]);
}
}
}
On removing the callback from this structure, these frequencies dont lead to stall the board
static struct rpmsg_driver beaglescope_driver= {
.drv.name = KBUILD_MODNAME,
.drv.owner = THIS_MODULE,
.id_table = beaglescope_id,
.probe = beaglescope_driver_probe,
.callback = beaglescope_driver_cb,
.remove = beaglescope_driver_remove,
};
Then tried these 2 versions of the callback -
- Commented out everything except the 'int count' instruction. And this version was working
static void beaglescope_driver_cb(struct rpmsg_channel *rpdev, void *data,
int len, void *priv, u32 src)
{
// struct beaglescope_state *st;
// struct iio_dev *indio_dev;
int count;
// indio_dev = dev_get_drvdata(&rpdev->dev);
// st = iio_priv(indio_dev);
// if (get_beaglescope_read_mode(st) == RAW_READ){
// log_debug("callback - raw mode");
// st->raw_data=*((u32 *)data);
// st->got_raw = 1;
// wake_up_interruptible(&st->wait_list);
// }else{
// for (count =0; count < len; count++) {
// iio_push_to_buffers(indio_dev, &((u8 *)data)[count]);
// }
// }
}
- Next version was with 'log_dbg()' and 'int count' instructions and the board got stalled.
static void beaglescope_driver_cb(struct rpmsg_channel *rpdev, void *data,
int len, void *priv, u32 src)
{
// struct beaglescope_state *st;
// struct iio_dev *indio_dev;
int count;
// indio_dev = dev_get_drvdata(&rpdev->dev);
// st = iio_priv(indio_dev);
log_debug("callback");
// if (get_beaglescope_read_mode(st) == RAW_READ){
// log_debug("callback - raw mode");
// st->raw_data=*((u32 *)data);
// st->got_raw = 1;
// wake_up_interruptible(&st->wait_list);
// }else{
// for (count =0; count < len; count++) {
// iio_push_to_buffers(indio_dev, &((u8 *)data)[count]);
// }
// }
}