From 2a77b9a952a5bec477319dc6f9cc6c85b2f46407 Mon Sep 17 00:00:00 2001 From: Frank Mori Hess Date: Wed, 17 Jul 2002 21:18:19 +0000 Subject: [PATCH] cleaning up logic for dealing with 8 bit dma transfers that get interrupted halfway through a sample --- comedi/drivers/das16.c | 129 ++++++++++++++++++++++++----------------- 1 file changed, 77 insertions(+), 52 deletions(-) diff --git a/comedi/drivers/das16.c b/comedi/drivers/das16.c index b9edb8be..d0dd7012 100644 --- a/comedi/drivers/das16.c +++ b/comedi/drivers/das16.c @@ -320,6 +320,12 @@ static comedi_lrange *das16_ai_bip_lranges[]={ &range_das1x02_bip, }; +struct munge_info +{ + uint8_t byte; + unsigned have_byte : 1; +}; + static int das16_ao_winsn(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data); static int das16_do_wbits(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data); static int das16_di_rbits(comedi_device *dev,comedi_subdevice *s,comedi_insn *insn,lsampl_t *data); @@ -338,6 +344,11 @@ static unsigned int das16_set_pacer(comedi_device *dev, unsigned int ns, int fla static int das1600_mode_detect(comedi_device *dev); static unsigned int das16_suggest_transfer_size(comedi_device *dev, comedi_cmd cmd); +static void init_munge_info( struct munge_info *info ); +static void write_byte_to_buffer( comedi_device *dev, comedi_subdevice *subd, + uint8_t raw_byte ); +static void das16_write_array_to_buffer( comedi_device *dev, void *data, unsigned int num_bytes ); + static void reg_dump(comedi_device *dev); typedef struct das16_board_struct{ @@ -707,23 +718,23 @@ static comedi_driver driver_das16={ static const int timer_period = HZ / 20 + 1; // period for timer interrupt in jiffies (about 1/20 of a second) -struct das16_private_struct { +struct das16_private_struct +{ unsigned int ai_unipolar; // unipolar flag unsigned int ai_singleended; // single ended flag unsigned int clockbase; // master clock speed in ns volatile unsigned int control_state; // dma, interrupt and trigger control bits - volatile unsigned int adc_count; // number of samples remaining - volatile unsigned int remains; // remaining bytes after last irq + volatile unsigned int adc_byte_count; // number of samples remaining unsigned int divisor1; // divisor dividing master clock to get conversion frequency unsigned int divisor2; // divisor dividing master clock to get conversion frequency unsigned int dma_chan; // dma channel - sampl_t *dma_buffer; - volatile unsigned int target_transfer_size; // target number of bytes to transfer per dma shot - volatile unsigned int actual_transfer_size; // number of bytes in current dma transfer + uint16_t *dma_buffer; + volatile unsigned int dma_transfer_size; // target number of bytes to transfer per dma shot // user-defined analog input and output ranges defined from config options comedi_lrange *user_ai_range_table; comedi_lrange *user_ao_range_table; - + struct munge_info ai_munge_info; + struct timer_list timer; // for timed interrupt volatile unsigned int timer_running : 1; volatile unsigned int timer_mode : 1; // true if using timer mode @@ -900,8 +911,9 @@ static int das16_cmd_exec(comedi_device *dev,comedi_subdevice *s) return -1; } - devpriv->adc_count = cmd->stop_arg * cmd->chanlist_len; - devpriv->remains = 0; + devpriv->adc_byte_count = cmd->stop_arg * cmd->chanlist_len * sizeof( uint16_t ); + + init_munge_info( &devpriv->ai_munge_info ); // disable conversions for das1600 mode if(thisboard->size > 0x400) @@ -952,9 +964,8 @@ static int das16_cmd_exec(comedi_device *dev,comedi_subdevice *s) clear_dma_ff(devpriv->dma_chan); set_dma_addr(devpriv->dma_chan, virt_to_bus(devpriv->dma_buffer)); // set appropriate size of transfer - devpriv->target_transfer_size = das16_suggest_transfer_size(dev, *cmd); - devpriv->actual_transfer_size = devpriv->target_transfer_size; - set_dma_count(devpriv->dma_chan, devpriv->actual_transfer_size); + devpriv->dma_transfer_size = das16_suggest_transfer_size(dev, *cmd); + set_dma_count(devpriv->dma_chan, devpriv->dma_transfer_size); enable_dma(devpriv->dma_chan); release_dma_lock(flags); @@ -1153,27 +1164,13 @@ static void das16_timer_interrupt(unsigned long arg) mod_timer(&devpriv->timer, jiffies + timer_period); } -static void munge_ai_data( comedi_device *dev, sampl_t *data, unsigned int num_points) -{ - unsigned int i; - - if( thisboard->ai_nbits == 12) - { - for(i = 0; i < num_points; i++) - { - data[i] = ( data[i] >> 4 ) & 0xfff; - } - } -} - static void das16_interrupt( comedi_device *dev ) { unsigned long flags; comedi_subdevice *s = dev->read_subdev; comedi_async *async; comedi_cmd *cmd; - int num_points, num_bytes, residue; - unsigned int target_xfer; + int num_bytes, residue; if(dev->attached == 0) { @@ -1183,7 +1180,6 @@ static void das16_interrupt( comedi_device *dev ) // initialize async here to make sure it is not NULL async = s->async; cmd = &async->cmd; - async->events = 0; flags = claim_dma_lock(); disable_dma(devpriv->dma_chan); @@ -1198,52 +1194,41 @@ static void das16_interrupt( comedi_device *dev ) * the stop_src is set to external triggering. */ residue = get_dma_residue(devpriv->dma_chan); - if(residue > devpriv->actual_transfer_size) + if(residue > devpriv->dma_transfer_size) { comedi_error(dev, "residue > transfer size!\n"); async->events |= COMEDI_CB_ERROR | COMEDI_CB_EOA; num_bytes = 0; }else - num_bytes = devpriv->actual_transfer_size + devpriv->remains - residue; - num_points = num_bytes / sample_size; - devpriv->remains = num_bytes % sample_size; + num_bytes = devpriv->dma_transfer_size - residue; if(cmd->stop_src == TRIG_COUNT && - num_points > devpriv->adc_count) + num_bytes > devpriv->adc_byte_count) { - num_points = devpriv->adc_count; + num_bytes = devpriv->adc_byte_count; async->events |= COMEDI_CB_EOA; } - munge_ai_data( dev, devpriv->dma_buffer, num_points ); - cfc_write_array_to_buffer( s, devpriv->dma_buffer, num_points * sizeof( sampl_t ) ); - devpriv->adc_count -= num_points; + das16_write_array_to_buffer( dev, devpriv->dma_buffer, num_bytes ); + devpriv->adc_byte_count -= num_bytes; // figure out how many bytes for next transfer - target_xfer = devpriv->target_transfer_size; if(cmd->stop_src == TRIG_COUNT && devpriv->timer_mode == 0 && - target_xfer > devpriv->adc_count * sample_size) - target_xfer = devpriv->adc_count * sample_size; - - devpriv->actual_transfer_size = target_xfer - devpriv->remains; + devpriv->dma_transfer_size > devpriv->adc_byte_count ) + devpriv->dma_transfer_size = devpriv->adc_byte_count; // re-enable dma if(( async->events & COMEDI_CB_EOA ) == 0) { - // copy possible leftover byte to beginning of buffer to be read next time - devpriv->dma_buffer[0] = devpriv->dma_buffer[num_points]; - set_dma_addr(devpriv->dma_chan, virt_to_bus(devpriv->dma_buffer) + devpriv->remains); - set_dma_count(devpriv->dma_chan, devpriv->actual_transfer_size); + set_dma_addr( devpriv->dma_chan, virt_to_bus( devpriv->dma_buffer ) ); + set_dma_count( devpriv->dma_chan, devpriv->dma_transfer_size ); enable_dma(devpriv->dma_chan); } release_dma_lock(flags); async->events |= COMEDI_CB_BLOCK; - if(async->events & COMEDI_CB_EOA) - das16_cancel(dev, s); - - comedi_event(dev, s, async->events); + cfc_handle_events( dev, s ); } static unsigned int das16_set_pacer(comedi_device *dev, unsigned int ns, int rounding_flags) @@ -1679,10 +1664,50 @@ static unsigned int das16_suggest_transfer_size(comedi_device *dev, comedi_cmd c else if(size < sample_size) size = sample_size; - if( cmd.stop_src == TRIG_COUNT && size > devpriv->adc_count * sample_size ) - size = devpriv->adc_count * sample_size; + if( cmd.stop_src == TRIG_COUNT && size > devpriv->adc_byte_count ) + size = devpriv->adc_byte_count; return size; } +static void init_munge_info( struct munge_info *info ) +{ + info->have_byte = 0; +} + +/* we want to be able to write one byte at a time to buffer to deal with + * possibility that 8-bit dma transfer will be interrupted inbetween + * least significant and most significant byte of a sample */ +static void write_byte_to_buffer( comedi_device *dev, comedi_subdevice *subd, uint8_t raw_byte ) +{ + sampl_t data; + struct munge_info *info = &devpriv->ai_munge_info; + + if( info->have_byte == 0 ) + { + info->byte = raw_byte; + info->have_byte = 1; + }else + { + info->have_byte = 0; + if( thisboard->ai_nbits == 12 ) + { + data = ( raw_byte << 4 ) & 0xff0; + data |= ( info->byte >> 4 ) & 0xf; + }else + { + data = raw_byte << 8 & 0xff00; + data |= info->byte & 0xff; + } + cfc_write_to_buffer( subd, data ); + } +} +static void das16_write_array_to_buffer( comedi_device *dev, void *data, unsigned int num_bytes ) +{ + unsigned int i; + uint8_t *array = data; + + for( i = 0; i < num_bytes; i++ ) + write_byte_to_buffer( dev, dev->read_subdev, array[i] ); +}; -- 2.26.2