Staging: comedi: add gsc_hpdi driver
authorFrank Mori Hess <fmhess@users.sourceforge.net>
Wed, 18 Feb 2009 00:30:02 +0000 (16:30 -0800)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 3 Apr 2009 21:53:45 +0000 (14:53 -0700)
Driver for the General Standards Corporation High Speed Parallel Digital
Interface rs485 boards.

From: Frank Mori Hess <fmhess@users.sourceforge.net>
Cc: David Schleef <ds@schleef.org>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/staging/comedi/drivers/gsc_hpdi.c [new file with mode: 0644]

diff --git a/drivers/staging/comedi/drivers/gsc_hpdi.c b/drivers/staging/comedi/drivers/gsc_hpdi.c
new file mode 100644 (file)
index 0000000..8d753e4
--- /dev/null
@@ -0,0 +1,1056 @@
+/*
+    comedi/drivers/gsc_hpdi.c
+    This is a driver for the General Standards Corporation High
+    Speed Parallel Digital Interface rs485 boards.
+
+    Author:  Frank Mori Hess <fmhess@users.sourceforge.net>
+    Copyright (C) 2003 Coherent Imaging Systems
+
+    COMEDI - Linux Control and Measurement Device Interface
+    Copyright (C) 1997-8 David A. Schleef <ds@schleef.org>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+************************************************************************/
+
+/*
+
+Driver: gsc_hpdi
+Description: General Standards Corporation High
+    Speed Parallel Digital Interface rs485 boards
+Author: Frank Mori Hess <fmhess@users.sourceforge.net>
+Status: only receive mode works, transmit not supported
+Updated: 2003-02-20
+Devices: [General Standards Corporation] PCI-HPDI32 (gsc_hpdi),
+  PMC-HPDI32
+
+Configuration options:
+   [0] - PCI bus of device (optional)
+   [1] - PCI slot of device (optional)
+
+There are some additional hpdi models available from GSC for which
+support could be added to this driver.
+
+*/
+
+#include "../comedidev.h"
+#include <linux/delay.h>
+
+#include "comedi_pci.h"
+#include "plx9080.h"
+#include "comedi_fc.h"
+
+static int hpdi_attach(comedi_device * dev, comedi_devconfig * it);
+static int hpdi_detach(comedi_device * dev);
+void abort_dma(comedi_device * dev, unsigned int channel);
+static int hpdi_cmd(comedi_device * dev, comedi_subdevice * s);
+static int hpdi_cmd_test(comedi_device * dev, comedi_subdevice * s,
+       comedi_cmd * cmd);
+static int hpdi_cancel(comedi_device * dev, comedi_subdevice * s);
+static irqreturn_t handle_interrupt(int irq, void *d PT_REGS_ARG);
+static int dio_config_block_size(comedi_device * dev, lsampl_t * data);
+
+#undef HPDI_DEBUG              // disable debugging messages
+//#define HPDI_DEBUG    // enable debugging code
+
+#ifdef HPDI_DEBUG
+#define DEBUG_PRINT(format, args...)  rt_printk(format , ## args )
+#else
+#define DEBUG_PRINT(format, args...)
+#endif
+
+#define TIMER_BASE 50          // 20MHz master clock
+#define DMA_BUFFER_SIZE 0x10000
+#define NUM_DMA_BUFFERS 4
+#define NUM_DMA_DESCRIPTORS 256
+
+// indices of base address regions
+enum base_address_regions {
+       PLX9080_BADDRINDEX = 0,
+       HPDI_BADDRINDEX = 2,
+};
+
+enum hpdi_registers {
+       FIRMWARE_REV_REG = 0x0,
+       BOARD_CONTROL_REG = 0x4,
+       BOARD_STATUS_REG = 0x8,
+       TX_PROG_ALMOST_REG = 0xc,
+       RX_PROG_ALMOST_REG = 0x10,
+       FEATURES_REG = 0x14,
+       FIFO_REG = 0x18,
+       TX_STATUS_COUNT_REG = 0x1c,
+       TX_LINE_VALID_COUNT_REG = 0x20,
+       TX_LINE_INVALID_COUNT_REG = 0x24,
+       RX_STATUS_COUNT_REG = 0x28,
+       RX_LINE_COUNT_REG = 0x2c,
+       INTERRUPT_CONTROL_REG = 0x30,
+       INTERRUPT_STATUS_REG = 0x34,
+       TX_CLOCK_DIVIDER_REG = 0x38,
+       TX_FIFO_SIZE_REG = 0x40,
+       RX_FIFO_SIZE_REG = 0x44,
+       TX_FIFO_WORDS_REG = 0x48,
+       RX_FIFO_WORDS_REG = 0x4c,
+       INTERRUPT_EDGE_LEVEL_REG = 0x50,
+       INTERRUPT_POLARITY_REG = 0x54,
+};
+
+int command_channel_valid(unsigned int channel)
+{
+       if (channel == 0 || channel > 6) {
+               rt_printk("gsc_hpdi: bug! invalid cable command channel\n");
+               return 0;
+       }
+       return 1;
+}
+
+// bit definitions
+
+enum firmware_revision_bits {
+       FEATURES_REG_PRESENT_BIT = 0x8000,
+};
+int firmware_revision(uint32_t fwr_bits)
+{
+       return fwr_bits & 0xff;
+}
+
+int pcb_revision(uint32_t fwr_bits)
+{
+       return (fwr_bits >> 8) & 0xff;
+}
+
+int hpdi_subid(uint32_t fwr_bits)
+{
+       return (fwr_bits >> 16) & 0xff;
+}
+
+enum board_control_bits {
+       BOARD_RESET_BIT = 0x1,  /* wait 10usec before accessing fifos */
+       TX_FIFO_RESET_BIT = 0x2,
+       RX_FIFO_RESET_BIT = 0x4,
+       TX_ENABLE_BIT = 0x10,
+       RX_ENABLE_BIT = 0x20,
+       DEMAND_DMA_DIRECTION_TX_BIT = 0x40,     /* for channel 0, channel 1 can only transmit (when present) */
+       LINE_VALID_ON_STATUS_VALID_BIT = 0x80,
+       START_TX_BIT = 0x10,
+       CABLE_THROTTLE_ENABLE_BIT = 0x20,
+       TEST_MODE_ENABLE_BIT = 0x80000000,
+};
+uint32_t command_discrete_output_bits(unsigned int channel, int output,
+       int output_value)
+{
+       uint32_t bits = 0;
+
+       if (command_channel_valid(channel) == 0)
+               return 0;
+       if (output) {
+               bits |= 0x1 << (16 + channel);
+               if (output_value)
+                       bits |= 0x1 << (24 + channel);
+       } else
+               bits |= 0x1 << (24 + channel);
+
+       return bits;
+}
+
+enum board_status_bits {
+       COMMAND_LINE_STATUS_MASK = 0x7f,
+       TX_IN_PROGRESS_BIT = 0x80,
+       TX_NOT_EMPTY_BIT = 0x100,
+       TX_NOT_ALMOST_EMPTY_BIT = 0x200,
+       TX_NOT_ALMOST_FULL_BIT = 0x400,
+       TX_NOT_FULL_BIT = 0x800,
+       RX_NOT_EMPTY_BIT = 0x1000,
+       RX_NOT_ALMOST_EMPTY_BIT = 0x2000,
+       RX_NOT_ALMOST_FULL_BIT = 0x4000,
+       RX_NOT_FULL_BIT = 0x8000,
+       BOARD_JUMPER0_INSTALLED_BIT = 0x10000,
+       BOARD_JUMPER1_INSTALLED_BIT = 0x20000,
+       TX_OVERRUN_BIT = 0x200000,
+       RX_UNDERRUN_BIT = 0x400000,
+       RX_OVERRUN_BIT = 0x800000,
+};
+
+uint32_t almost_full_bits(unsigned int num_words)
+{
+// XXX need to add or subtract one?
+       return (num_words << 16) & 0xff0000;
+}
+
+uint32_t almost_empty_bits(unsigned int num_words)
+{
+       return num_words & 0xffff;
+}
+unsigned int almost_full_num_words(uint32_t bits)
+{
+// XXX need to add or subtract one?
+       return (bits >> 16) & 0xffff;
+}
+unsigned int almost_empty_num_words(uint32_t bits)
+{
+       return bits & 0xffff;
+}
+
+enum features_bits {
+       FIFO_SIZE_PRESENT_BIT = 0x1,
+       FIFO_WORDS_PRESENT_BIT = 0x2,
+       LEVEL_EDGE_INTERRUPTS_PRESENT_BIT = 0x4,
+       GPIO_SUPPORTED_BIT = 0x8,
+       PLX_DMA_CH1_SUPPORTED_BIT = 0x10,
+       OVERRUN_UNDERRUN_SUPPORTED_BIT = 0x20,
+};
+
+enum interrupt_sources {
+       FRAME_VALID_START_INTR = 0,
+       FRAME_VALID_END_INTR = 1,
+       TX_FIFO_EMPTY_INTR = 8,
+       TX_FIFO_ALMOST_EMPTY_INTR = 9,
+       TX_FIFO_ALMOST_FULL_INTR = 10,
+       TX_FIFO_FULL_INTR = 11,
+       RX_EMPTY_INTR = 12,
+       RX_ALMOST_EMPTY_INTR = 13,
+       RX_ALMOST_FULL_INTR = 14,
+       RX_FULL_INTR = 15,
+};
+int command_intr_source(unsigned int channel)
+{
+       if (command_channel_valid(channel) == 0)
+               channel = 1;
+       return channel + 1;
+}
+
+uint32_t intr_bit(int interrupt_source)
+{
+       return 0x1 << interrupt_source;
+}
+
+uint32_t tx_clock_divisor_bits(unsigned int divisor)
+{
+       return divisor & 0xff;
+}
+
+unsigned int fifo_size(uint32_t fifo_size_bits)
+{
+       return fifo_size_bits & 0xfffff;
+}
+
+unsigned int fifo_words(uint32_t fifo_words_bits)
+{
+       return fifo_words_bits & 0xfffff;
+}
+
+uint32_t intr_edge_bit(int interrupt_source)
+{
+       return 0x1 << interrupt_source;
+}
+
+uint32_t intr_active_high_bit(int interrupt_source)
+{
+       return 0x1 << interrupt_source;
+}
+
+typedef struct {
+       char *name;
+       int device_id;          // pci device id
+       int subdevice_id;       // pci subdevice id
+} hpdi_board;
+
+static const hpdi_board hpdi_boards[] = {
+       {
+             name:     "pci-hpdi32",
+             device_id:PCI_DEVICE_ID_PLX_9080,
+             subdevice_id:0x2400,
+               },
+#if 0
+       {
+             name:     "pxi-hpdi32",
+             device_id:0x9656,
+             subdevice_id:0x2705,
+               },
+#endif
+};
+
+static inline unsigned int num_boards(void)
+{
+       return sizeof(hpdi_boards) / sizeof(hpdi_board);
+}
+
+static DEFINE_PCI_DEVICE_TABLE(hpdi_pci_table) = {
+       {PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_9080, PCI_VENDOR_ID_PLX, 0x2400,
+               0, 0, 0},
+       {0}
+};
+
+MODULE_DEVICE_TABLE(pci, hpdi_pci_table);
+
+static inline hpdi_board *board(const comedi_device * dev)
+{
+       return (hpdi_board *) dev->board_ptr;
+}
+
+typedef struct {
+       struct pci_dev *hw_dev; // pointer to board's pci_dev struct
+       // base addresses (physical)
+       resource_size_t plx9080_phys_iobase;
+       resource_size_t hpdi_phys_iobase;
+       // base addresses (ioremapped)
+       void *plx9080_iobase;
+       void *hpdi_iobase;
+       uint32_t *dio_buffer[NUM_DMA_BUFFERS];  // dma buffers
+       dma_addr_t dio_buffer_phys_addr[NUM_DMA_BUFFERS];       // physical addresses of dma buffers
+       struct plx_dma_desc *dma_desc;  // array of dma descriptors read by plx9080, allocated to get proper alignment
+       dma_addr_t dma_desc_phys_addr;  // physical address of dma descriptor array
+       unsigned int num_dma_descriptors;
+       uint32_t *desc_dio_buffer[NUM_DMA_DESCRIPTORS]; // pointer to start of buffers indexed by descriptor
+       volatile unsigned int dma_desc_index;   // index of the dma descriptor that is currently being used
+       unsigned int tx_fifo_size;
+       unsigned int rx_fifo_size;
+       volatile unsigned long dio_count;
+       volatile uint32_t bits[24];     // software copies of values written to hpdi registers
+       volatile unsigned int block_size;       // number of bytes at which to generate COMEDI_CB_BLOCK events
+       unsigned dio_config_output:1;
+} hpdi_private;
+
+static inline hpdi_private *priv(comedi_device * dev)
+{
+       return dev->private;
+}
+
+static comedi_driver driver_hpdi = {
+      driver_name:"gsc_hpdi",
+      module:THIS_MODULE,
+      attach:hpdi_attach,
+      detach:hpdi_detach,
+};
+
+COMEDI_PCI_INITCLEANUP(driver_hpdi, hpdi_pci_table);
+
+static int dio_config_insn(comedi_device * dev, comedi_subdevice * s,
+       comedi_insn * insn, lsampl_t * data)
+{
+       switch (data[0]) {
+       case INSN_CONFIG_DIO_OUTPUT:
+               priv(dev)->dio_config_output = 1;
+               return insn->n;
+               break;
+       case INSN_CONFIG_DIO_INPUT:
+               priv(dev)->dio_config_output = 0;
+               return insn->n;
+               break;
+       case INSN_CONFIG_DIO_QUERY:
+               data[1] =
+                       priv(dev)->
+                       dio_config_output ? COMEDI_OUTPUT : COMEDI_INPUT;
+               return insn->n;
+               break;
+       case INSN_CONFIG_BLOCK_SIZE:
+               return dio_config_block_size(dev, data);
+               break;
+       default:
+               break;
+       }
+
+       return -EINVAL;
+}
+
+static void disable_plx_interrupts(comedi_device * dev)
+{
+       writel(0, priv(dev)->plx9080_iobase + PLX_INTRCS_REG);
+}
+
+// initialize plx9080 chip
+static void init_plx9080(comedi_device * dev)
+{
+       uint32_t bits;
+       void *plx_iobase = priv(dev)->plx9080_iobase;
+
+       // plx9080 dump
+       DEBUG_PRINT(" plx interrupt status 0x%x\n",
+               readl(plx_iobase + PLX_INTRCS_REG));
+       DEBUG_PRINT(" plx id bits 0x%x\n", readl(plx_iobase + PLX_ID_REG));
+       DEBUG_PRINT(" plx control reg 0x%x\n",
+               readl(priv(dev)->plx9080_iobase + PLX_CONTROL_REG));
+
+       DEBUG_PRINT(" plx revision 0x%x\n",
+               readl(plx_iobase + PLX_REVISION_REG));
+       DEBUG_PRINT(" plx dma channel 0 mode 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_MODE_REG));
+       DEBUG_PRINT(" plx dma channel 1 mode 0x%x\n",
+               readl(plx_iobase + PLX_DMA1_MODE_REG));
+       DEBUG_PRINT(" plx dma channel 0 pci address 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_PCI_ADDRESS_REG));
+       DEBUG_PRINT(" plx dma channel 0 local address 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_LOCAL_ADDRESS_REG));
+       DEBUG_PRINT(" plx dma channel 0 transfer size 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_TRANSFER_SIZE_REG));
+       DEBUG_PRINT(" plx dma channel 0 descriptor 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_DESCRIPTOR_REG));
+       DEBUG_PRINT(" plx dma channel 0 command status 0x%x\n",
+               readb(plx_iobase + PLX_DMA0_CS_REG));
+       DEBUG_PRINT(" plx dma channel 0 threshold 0x%x\n",
+               readl(plx_iobase + PLX_DMA0_THRESHOLD_REG));
+       DEBUG_PRINT(" plx bigend 0x%x\n", readl(plx_iobase + PLX_BIGEND_REG));
+#ifdef __BIG_ENDIAN
+       bits = BIGEND_DMA0 | BIGEND_DMA1;
+#else
+       bits = 0;
+#endif
+       writel(bits, priv(dev)->plx9080_iobase + PLX_BIGEND_REG);
+
+       disable_plx_interrupts(dev);
+
+       abort_dma(dev, 0);
+       abort_dma(dev, 1);
+
+       // configure dma0 mode
+       bits = 0;
+       // enable ready input
+       bits |= PLX_DMA_EN_READYIN_BIT;
+       // enable dma chaining
+       bits |= PLX_EN_CHAIN_BIT;
+       // enable interrupt on dma done (probably don't need this, since chain never finishes)
+       bits |= PLX_EN_DMA_DONE_INTR_BIT;
+       // don't increment local address during transfers (we are transferring from a fixed fifo register)
+       bits |= PLX_LOCAL_ADDR_CONST_BIT;
+       // route dma interrupt to pci bus
+       bits |= PLX_DMA_INTR_PCI_BIT;
+       // enable demand mode
+       bits |= PLX_DEMAND_MODE_BIT;
+       // enable local burst mode
+       bits |= PLX_DMA_LOCAL_BURST_EN_BIT;
+       bits |= PLX_LOCAL_BUS_32_WIDE_BITS;
+       writel(bits, plx_iobase + PLX_DMA0_MODE_REG);
+}
+
+/* Allocate and initialize the subdevice structures.
+ */
+static int setup_subdevices(comedi_device * dev)
+{
+       comedi_subdevice *s;
+
+       if (alloc_subdevices(dev, 1) < 0)
+               return -ENOMEM;
+
+       s = dev->subdevices + 0;
+       /* analog input subdevice */
+       dev->read_subdev = s;
+/*     dev->write_subdev = s; */
+       s->type = COMEDI_SUBD_DIO;
+       s->subdev_flags =
+               SDF_READABLE | SDF_WRITEABLE | SDF_LSAMPL | SDF_CMD_READ;
+       s->n_chan = 32;
+       s->len_chanlist = 32;
+       s->maxdata = 1;
+       s->range_table = &range_digital;
+       s->insn_config = dio_config_insn;
+       s->do_cmd = hpdi_cmd;
+       s->do_cmdtest = hpdi_cmd_test;
+       s->cancel = hpdi_cancel;
+
+       return 0;
+}
+
+static int init_hpdi(comedi_device * dev)
+{
+       uint32_t plx_intcsr_bits;
+
+       writel(BOARD_RESET_BIT, priv(dev)->hpdi_iobase + BOARD_CONTROL_REG);
+       comedi_udelay(10);
+
+       writel(almost_empty_bits(32) | almost_full_bits(32),
+               priv(dev)->hpdi_iobase + RX_PROG_ALMOST_REG);
+       writel(almost_empty_bits(32) | almost_full_bits(32),
+               priv(dev)->hpdi_iobase + TX_PROG_ALMOST_REG);
+
+       priv(dev)->tx_fifo_size = fifo_size(readl(priv(dev)->hpdi_iobase +
+                       TX_FIFO_SIZE_REG));
+       priv(dev)->rx_fifo_size = fifo_size(readl(priv(dev)->hpdi_iobase +
+                       RX_FIFO_SIZE_REG));
+
+       writel(0, priv(dev)->hpdi_iobase + INTERRUPT_CONTROL_REG);
+
+       // enable interrupts
+       plx_intcsr_bits =
+               ICS_AERR | ICS_PERR | ICS_PIE | ICS_PLIE | ICS_PAIE | ICS_LIE |
+               ICS_DMA0_E;
+       writel(plx_intcsr_bits, priv(dev)->plx9080_iobase + PLX_INTRCS_REG);
+
+       return 0;
+}
+
+// setup dma descriptors so a link completes every 'transfer_size' bytes
+static int setup_dma_descriptors(comedi_device * dev,
+       unsigned int transfer_size)
+{
+       unsigned int buffer_index, buffer_offset;
+       uint32_t next_bits = PLX_DESC_IN_PCI_BIT | PLX_INTR_TERM_COUNT |
+               PLX_XFER_LOCAL_TO_PCI;
+       unsigned int i;
+
+       if (transfer_size > DMA_BUFFER_SIZE)
+               transfer_size = DMA_BUFFER_SIZE;
+       transfer_size -= transfer_size % sizeof(uint32_t);
+       if (transfer_size == 0)
+               return -1;
+
+       DEBUG_PRINT(" transfer_size %i\n", transfer_size);
+       DEBUG_PRINT(" descriptors at 0x%lx\n",
+               (unsigned long)priv(dev)->dma_desc_phys_addr);
+
+       buffer_offset = 0;
+       buffer_index = 0;
+       for (i = 0; i < NUM_DMA_DESCRIPTORS &&
+               buffer_index < NUM_DMA_BUFFERS; i++) {
+               priv(dev)->dma_desc[i].pci_start_addr =
+                       cpu_to_le32(priv(dev)->
+                       dio_buffer_phys_addr[buffer_index] + buffer_offset);
+               priv(dev)->dma_desc[i].local_start_addr = cpu_to_le32(FIFO_REG);
+               priv(dev)->dma_desc[i].transfer_size =
+                       cpu_to_le32(transfer_size);
+               priv(dev)->dma_desc[i].next =
+                       cpu_to_le32((priv(dev)->dma_desc_phys_addr + (i +
+                                       1) *
+                               sizeof(priv(dev)->dma_desc[0])) | next_bits);
+
+               priv(dev)->desc_dio_buffer[i] =
+                       priv(dev)->dio_buffer[buffer_index] +
+                       (buffer_offset / sizeof(uint32_t));
+
+               buffer_offset += transfer_size;
+               if (transfer_size + buffer_offset > DMA_BUFFER_SIZE) {
+                       buffer_offset = 0;
+                       buffer_index++;
+               }
+
+               DEBUG_PRINT(" desc %i\n", i);
+               DEBUG_PRINT(" start addr virt 0x%p, phys 0x%lx\n",
+                       priv(dev)->desc_dio_buffer[i],
+                       (unsigned long)priv(dev)->dma_desc[i].pci_start_addr);
+               DEBUG_PRINT(" next 0x%lx\n",
+                       (unsigned long)priv(dev)->dma_desc[i].next);
+       }
+       priv(dev)->num_dma_descriptors = i;
+       // fix last descriptor to point back to first
+       priv(dev)->dma_desc[i - 1].next =
+               cpu_to_le32(priv(dev)->dma_desc_phys_addr | next_bits);
+       DEBUG_PRINT(" desc %i next fixup 0x%lx\n", i - 1,
+               (unsigned long)priv(dev)->dma_desc[i - 1].next);
+
+       priv(dev)->block_size = transfer_size;
+
+       return transfer_size;
+}
+
+static int hpdi_attach(comedi_device * dev, comedi_devconfig * it)
+{
+       struct pci_dev *pcidev;
+       int i;
+       int retval;
+
+       printk("comedi%d: gsc_hpdi\n", dev->minor);
+
+       if (alloc_private(dev, sizeof(hpdi_private)) < 0)
+               return -ENOMEM;
+
+       pcidev = NULL;
+       for (i = 0; i < num_boards() && dev->board_ptr == NULL; i++) {
+               do {
+                       pcidev = pci_get_subsys(PCI_VENDOR_ID_PLX,
+                               hpdi_boards[i].device_id, PCI_VENDOR_ID_PLX,
+                               hpdi_boards[i].subdevice_id, pcidev);
+                       // was a particular bus/slot requested?
+                       if (it->options[0] || it->options[1]) {
+                               // are we on the wrong bus/slot?
+                               if (pcidev->bus->number != it->options[0] ||
+                                       PCI_SLOT(pcidev->devfn) !=
+                                       it->options[1])
+                                       continue;
+                       }
+                       if (pcidev) {
+                               priv(dev)->hw_dev = pcidev;
+                               dev->board_ptr = hpdi_boards + i;
+                               break;
+                       }
+               } while (pcidev != NULL);
+       }
+       if (dev->board_ptr == NULL) {
+               printk("gsc_hpdi: no hpdi card found\n");
+               return -EIO;
+       }
+
+       printk("gsc_hpdi: found %s on bus %i, slot %i\n", board(dev)->name,
+               pcidev->bus->number, PCI_SLOT(pcidev->devfn));
+
+       if (comedi_pci_enable(pcidev, driver_hpdi.driver_name)) {
+               printk(KERN_WARNING
+                       " failed enable PCI device and request regions\n");
+               return -EIO;
+       }
+       pci_set_master(pcidev);
+
+       //Initialize dev->board_name
+       dev->board_name = board(dev)->name;
+
+       priv(dev)->plx9080_phys_iobase =
+               pci_resource_start(pcidev, PLX9080_BADDRINDEX);
+       priv(dev)->hpdi_phys_iobase =
+               pci_resource_start(pcidev, HPDI_BADDRINDEX);
+
+       // remap, won't work with 2.0 kernels but who cares
+       priv(dev)->plx9080_iobase = ioremap(priv(dev)->plx9080_phys_iobase,
+               pci_resource_len(pcidev, PLX9080_BADDRINDEX));
+       priv(dev)->hpdi_iobase = ioremap(priv(dev)->hpdi_phys_iobase,
+               pci_resource_len(pcidev, HPDI_BADDRINDEX));
+       if (!priv(dev)->plx9080_iobase || !priv(dev)->hpdi_iobase) {
+               printk(" failed to remap io memory\n");
+               return -ENOMEM;
+       }
+
+       DEBUG_PRINT(" plx9080 remapped to 0x%p\n", priv(dev)->plx9080_iobase);
+       DEBUG_PRINT(" hpdi remapped to 0x%p\n", priv(dev)->hpdi_iobase);
+
+       init_plx9080(dev);
+
+       // get irq
+       if (comedi_request_irq(pcidev->irq, handle_interrupt, IRQF_SHARED,
+                       driver_hpdi.driver_name, dev)) {
+               printk(" unable to allocate irq %u\n", pcidev->irq);
+               return -EINVAL;
+       }
+       dev->irq = pcidev->irq;
+
+       printk(" irq %u\n", dev->irq);
+
+       // alocate pci dma buffers
+       for (i = 0; i < NUM_DMA_BUFFERS; i++) {
+               priv(dev)->dio_buffer[i] =
+                       pci_alloc_consistent(priv(dev)->hw_dev, DMA_BUFFER_SIZE,
+                       &priv(dev)->dio_buffer_phys_addr[i]);
+               DEBUG_PRINT("dio_buffer at virt 0x%p, phys 0x%lx\n",
+                       priv(dev)->dio_buffer[i],
+                       (unsigned long)priv(dev)->dio_buffer_phys_addr[i]);
+       }
+       // allocate dma descriptors
+       priv(dev)->dma_desc = pci_alloc_consistent(priv(dev)->hw_dev,
+               sizeof(struct plx_dma_desc) * NUM_DMA_DESCRIPTORS,
+               &priv(dev)->dma_desc_phys_addr);
+       if (priv(dev)->dma_desc_phys_addr & 0xf) {
+               printk(" dma descriptors not quad-word aligned (bug)\n");
+               return -EIO;
+       }
+
+       retval = setup_dma_descriptors(dev, 0x1000);
+       if (retval < 0)
+               return retval;
+
+       retval = setup_subdevices(dev);
+       if (retval < 0)
+               return retval;
+
+       return init_hpdi(dev);
+}
+
+static int hpdi_detach(comedi_device * dev)
+{
+       unsigned int i;
+
+       printk("comedi%d: gsc_hpdi: remove\n", dev->minor);
+
+       if (dev->irq)
+               comedi_free_irq(dev->irq, dev);
+       if (priv(dev)) {
+               if (priv(dev)->hw_dev) {
+                       if (priv(dev)->plx9080_iobase) {
+                               disable_plx_interrupts(dev);
+                               iounmap((void *)priv(dev)->plx9080_iobase);
+                       }
+                       if (priv(dev)->hpdi_iobase)
+                               iounmap((void *)priv(dev)->hpdi_iobase);
+                       // free pci dma buffers
+                       for (i = 0; i < NUM_DMA_BUFFERS; i++) {
+                               if (priv(dev)->dio_buffer[i])
+                                       pci_free_consistent(priv(dev)->hw_dev,
+                                               DMA_BUFFER_SIZE,
+                                               priv(dev)->dio_buffer[i],
+                                               priv(dev)->
+                                               dio_buffer_phys_addr[i]);
+                       }
+                       // free dma descriptors
+                       if (priv(dev)->dma_desc)
+                               pci_free_consistent(priv(dev)->hw_dev,
+                                       sizeof(struct plx_dma_desc) *
+                                       NUM_DMA_DESCRIPTORS,
+                                       priv(dev)->dma_desc,
+                                       priv(dev)->dma_desc_phys_addr);
+                       if (priv(dev)->hpdi_phys_iobase) {
+                               comedi_pci_disable(priv(dev)->hw_dev);
+                       }
+                       pci_dev_put(priv(dev)->hw_dev);
+               }
+       }
+       return 0;
+}
+
+static int dio_config_block_size(comedi_device * dev, lsampl_t * data)
+{
+       unsigned int requested_block_size;
+       int retval;
+
+       requested_block_size = data[1];
+
+       retval = setup_dma_descriptors(dev, requested_block_size);
+       if (retval < 0)
+               return retval;
+
+       data[1] = retval;
+
+       return 2;
+}
+
+static int di_cmd_test(comedi_device * dev, comedi_subdevice * s,
+       comedi_cmd * cmd)
+{
+       int err = 0;
+       int tmp;
+       int i;
+
+       /* step 1: make sure trigger sources are trivially valid */
+
+       tmp = cmd->start_src;
+       cmd->start_src &= TRIG_NOW;
+       if (!cmd->start_src || tmp != cmd->start_src)
+               err++;
+
+       tmp = cmd->scan_begin_src;
+       cmd->scan_begin_src &= TRIG_EXT;
+       if (!cmd->scan_begin_src || tmp != cmd->scan_begin_src)
+               err++;
+
+       tmp = cmd->convert_src;
+       cmd->convert_src &= TRIG_NOW;
+       if (!cmd->convert_src || tmp != cmd->convert_src)
+               err++;
+
+       tmp = cmd->scan_end_src;
+       cmd->scan_end_src &= TRIG_COUNT;
+       if (!cmd->scan_end_src || tmp != cmd->scan_end_src)
+               err++;
+
+       tmp = cmd->stop_src;
+       cmd->stop_src &= TRIG_COUNT | TRIG_NONE;
+       if (!cmd->stop_src || tmp != cmd->stop_src)
+               err++;
+
+       if (err)
+               return 1;
+
+       /* step 2: make sure trigger sources are unique and mutually compatible */
+
+       // uniqueness check
+       if (cmd->stop_src != TRIG_COUNT && cmd->stop_src != TRIG_NONE)
+               err++;
+
+       if (err)
+               return 2;
+
+       /* step 3: make sure arguments are trivially compatible */
+
+       if (!cmd->chanlist_len) {
+               cmd->chanlist_len = 32;
+               err++;
+       }
+       if (cmd->scan_end_arg != cmd->chanlist_len) {
+               cmd->scan_end_arg = cmd->chanlist_len;
+               err++;
+       }
+
+       switch (cmd->stop_src) {
+       case TRIG_COUNT:
+               if (!cmd->stop_arg) {
+                       cmd->stop_arg = 1;
+                       err++;
+               }
+               break;
+       case TRIG_NONE:
+               if (cmd->stop_arg != 0) {
+                       cmd->stop_arg = 0;
+                       err++;
+               }
+               break;
+       default:
+               break;
+       }
+
+       if (err)
+               return 3;
+
+       /* step 4: fix up any arguments */
+
+       if (err)
+               return 4;
+
+       if (cmd->chanlist) {
+               for (i = 1; i < cmd->chanlist_len; i++) {
+                       if (CR_CHAN(cmd->chanlist[i]) != i) {
+                               // XXX could support 8 channels or 16 channels
+                               comedi_error(dev,
+                                       "chanlist must be channels 0 to 31 in order");
+                               err++;
+                               break;
+                       }
+               }
+       }
+
+       if (err)
+               return 5;
+
+       return 0;
+}
+
+static int hpdi_cmd_test(comedi_device * dev, comedi_subdevice * s,
+       comedi_cmd * cmd)
+{
+       if (priv(dev)->dio_config_output) {
+               return -EINVAL;
+       } else
+               return di_cmd_test(dev, s, cmd);
+}
+
+static inline void hpdi_writel(comedi_device * dev, uint32_t bits,
+       unsigned int offset)
+{
+       writel(bits | priv(dev)->bits[offset / sizeof(uint32_t)],
+               priv(dev)->hpdi_iobase + offset);
+}
+
+static int di_cmd(comedi_device * dev, comedi_subdevice * s)
+{
+       uint32_t bits;
+       unsigned long flags;
+       comedi_async *async = s->async;
+       comedi_cmd *cmd = &async->cmd;
+
+       hpdi_writel(dev, RX_FIFO_RESET_BIT, BOARD_CONTROL_REG);
+
+       DEBUG_PRINT("hpdi: in di_cmd\n");
+
+       abort_dma(dev, 0);
+
+       priv(dev)->dma_desc_index = 0;
+
+       /* These register are supposedly unused during chained dma,
+        * but I have found that left over values from last operation
+        * occasionally cause problems with transfer of first dma
+        * block.  Initializing them to zero seems to fix the problem. */
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_TRANSFER_SIZE_REG);
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_PCI_ADDRESS_REG);
+       writel(0, priv(dev)->plx9080_iobase + PLX_DMA0_LOCAL_ADDRESS_REG);
+       // give location of first dma descriptor
+       bits = priv(dev)->
+               dma_desc_phys_addr | PLX_DESC_IN_PCI_BIT | PLX_INTR_TERM_COUNT |
+               PLX_XFER_LOCAL_TO_PCI;
+       writel(bits, priv(dev)->plx9080_iobase + PLX_DMA0_DESCRIPTOR_REG);
+
+       // spinlock for plx dma control/status reg
+       comedi_spin_lock_irqsave(&dev->spinlock, flags);
+       // enable dma transfer
+       writeb(PLX_DMA_EN_BIT | PLX_DMA_START_BIT | PLX_CLEAR_DMA_INTR_BIT,
+               priv(dev)->plx9080_iobase + PLX_DMA0_CS_REG);
+       comedi_spin_unlock_irqrestore(&dev->spinlock, flags);
+
+       if (cmd->stop_src == TRIG_COUNT)
+               priv(dev)->dio_count = cmd->stop_arg;
+       else
+               priv(dev)->dio_count = 1;
+
+       // clear over/under run status flags
+       writel(RX_UNDERRUN_BIT | RX_OVERRUN_BIT,
+               priv(dev)->hpdi_iobase + BOARD_STATUS_REG);
+       // enable interrupts
+       writel(intr_bit(RX_FULL_INTR),
+               priv(dev)->hpdi_iobase + INTERRUPT_CONTROL_REG);
+
+       DEBUG_PRINT("hpdi: starting rx\n");
+       hpdi_writel(dev, RX_ENABLE_BIT, BOARD_CONTROL_REG);
+
+       return 0;
+}
+
+static int hpdi_cmd(comedi_device * dev, comedi_subdevice * s)
+{
+       if (priv(dev)->dio_config_output) {
+               return -EINVAL;
+       } else
+               return di_cmd(dev, s);
+}
+
+static void drain_dma_buffers(comedi_device * dev, unsigned int channel)
+{
+       comedi_async *async = dev->read_subdev->async;
+       uint32_t next_transfer_addr;
+       int j;
+       int num_samples = 0;
+       void *pci_addr_reg;
+
+       if (channel)
+               pci_addr_reg =
+                       priv(dev)->plx9080_iobase + PLX_DMA1_PCI_ADDRESS_REG;
+       else
+               pci_addr_reg =
+                       priv(dev)->plx9080_iobase + PLX_DMA0_PCI_ADDRESS_REG;
+
+       // loop until we have read all the full buffers
+       j = 0;
+       for (next_transfer_addr = readl(pci_addr_reg);
+               (next_transfer_addr <
+                       le32_to_cpu(priv(dev)->dma_desc[priv(dev)->
+                                       dma_desc_index].pci_start_addr)
+                       || next_transfer_addr >=
+                       le32_to_cpu(priv(dev)->dma_desc[priv(dev)->
+                                       dma_desc_index].pci_start_addr) +
+                       priv(dev)->block_size)
+               && j < priv(dev)->num_dma_descriptors; j++) {
+               // transfer data from dma buffer to comedi buffer
+               num_samples = priv(dev)->block_size / sizeof(uint32_t);
+               if (async->cmd.stop_src == TRIG_COUNT) {
+                       if (num_samples > priv(dev)->dio_count)
+                               num_samples = priv(dev)->dio_count;
+                       priv(dev)->dio_count -= num_samples;
+               }
+               cfc_write_array_to_buffer(dev->read_subdev,
+                       priv(dev)->desc_dio_buffer[priv(dev)->dma_desc_index],
+                       num_samples * sizeof(uint32_t));
+               priv(dev)->dma_desc_index++;
+               priv(dev)->dma_desc_index %= priv(dev)->num_dma_descriptors;
+
+               DEBUG_PRINT("next desc addr 0x%lx\n", (unsigned long)
+                       priv(dev)->dma_desc[priv(dev)->dma_desc_index].next);
+               DEBUG_PRINT("pci addr reg 0x%x\n", next_transfer_addr);
+       }
+       // XXX check for buffer overrun somehow
+}
+
+static irqreturn_t handle_interrupt(int irq, void *d PT_REGS_ARG)
+{
+       comedi_device *dev = d;
+       comedi_subdevice *s = dev->read_subdev;
+       comedi_async *async = s->async;
+       uint32_t hpdi_intr_status, hpdi_board_status;
+       uint32_t plx_status;
+       uint32_t plx_bits;
+       uint8_t dma0_status, dma1_status;
+       unsigned long flags;
+
+       if (!dev->attached) {
+               return IRQ_NONE;
+       }
+
+       plx_status = readl(priv(dev)->plx9080_iobase + PLX_INTRCS_REG);
+       if ((plx_status & (ICS_DMA0_A | ICS_DMA1_A | ICS_LIA)) == 0) {
+               return IRQ_NONE;
+       }
+
+       hpdi_intr_status = readl(priv(dev)->hpdi_iobase + INTERRUPT_STATUS_REG);
+       hpdi_board_status = readl(priv(dev)->hpdi_iobase + BOARD_STATUS_REG);
+
+       async->events = 0;
+
+       if (hpdi_intr_status) {
+               DEBUG_PRINT("hpdi: intr status 0x%x, ", hpdi_intr_status);
+               writel(hpdi_intr_status,
+                       priv(dev)->hpdi_iobase + INTERRUPT_STATUS_REG);
+       }
+       // spin lock makes sure noone else changes plx dma control reg
+       comedi_spin_lock_irqsave(&dev->spinlock, flags);
+       dma0_status = readb(priv(dev)->plx9080_iobase + PLX_DMA0_CS_REG);
+       if (plx_status & ICS_DMA0_A) {  // dma chan 0 interrupt
+               writeb((dma0_status & PLX_DMA_EN_BIT) | PLX_CLEAR_DMA_INTR_BIT,
+                       priv(dev)->plx9080_iobase + PLX_DMA0_CS_REG);
+
+               DEBUG_PRINT("dma0 status 0x%x\n", dma0_status);
+               if (dma0_status & PLX_DMA_EN_BIT) {
+                       drain_dma_buffers(dev, 0);
+               }
+               DEBUG_PRINT(" cleared dma ch0 interrupt\n");
+       }
+       comedi_spin_unlock_irqrestore(&dev->spinlock, flags);
+
+       // spin lock makes sure noone else changes plx dma control reg
+       comedi_spin_lock_irqsave(&dev->spinlock, flags);
+       dma1_status = readb(priv(dev)->plx9080_iobase + PLX_DMA1_CS_REG);
+       if (plx_status & ICS_DMA1_A)    // XXX
+       {                       // dma chan 1 interrupt
+               writeb((dma1_status & PLX_DMA_EN_BIT) | PLX_CLEAR_DMA_INTR_BIT,
+                       priv(dev)->plx9080_iobase + PLX_DMA1_CS_REG);
+               DEBUG_PRINT("dma1 status 0x%x\n", dma1_status);
+
+               DEBUG_PRINT(" cleared dma ch1 interrupt\n");
+       }
+       comedi_spin_unlock_irqrestore(&dev->spinlock, flags);
+
+       // clear possible plx9080 interrupt sources
+       if (plx_status & ICS_LDIA) {    // clear local doorbell interrupt
+               plx_bits = readl(priv(dev)->plx9080_iobase + PLX_DBR_OUT_REG);
+               writel(plx_bits, priv(dev)->plx9080_iobase + PLX_DBR_OUT_REG);
+               DEBUG_PRINT(" cleared local doorbell bits 0x%x\n", plx_bits);
+       }
+
+       if (hpdi_board_status & RX_OVERRUN_BIT) {
+               comedi_error(dev, "rx fifo overrun");
+               async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
+               DEBUG_PRINT("dma0_status 0x%x\n",
+                       (int)readb(priv(dev)->plx9080_iobase +
+                               PLX_DMA0_CS_REG));
+       }
+
+       if (hpdi_board_status & RX_UNDERRUN_BIT) {
+               comedi_error(dev, "rx fifo underrun");
+               async->events |= COMEDI_CB_EOA | COMEDI_CB_ERROR;
+       }
+
+       if (priv(dev)->dio_count == 0)
+               async->events |= COMEDI_CB_EOA;
+
+       DEBUG_PRINT("board status 0x%x, ", hpdi_board_status);
+       DEBUG_PRINT("plx status 0x%x\n", plx_status);
+       if (async->events)
+               DEBUG_PRINT(" events 0x%x\n", async->events);
+
+       cfc_handle_events(dev, s);
+
+       return IRQ_HANDLED;
+}
+
+void abort_dma(comedi_device * dev, unsigned int channel)
+{
+       unsigned long flags;
+
+       // spinlock for plx dma control/status reg
+       comedi_spin_lock_irqsave(&dev->spinlock, flags);
+
+       plx9080_abort_dma(priv(dev)->plx9080_iobase, channel);
+
+       comedi_spin_unlock_irqrestore(&dev->spinlock, flags);
+}
+
+static int hpdi_cancel(comedi_device * dev, comedi_subdevice * s)
+{
+       hpdi_writel(dev, 0, BOARD_CONTROL_REG);
+
+       writel(0, priv(dev)->hpdi_iobase + INTERRUPT_CONTROL_REG);
+
+       abort_dma(dev, 0);
+
+       return 0;
+}