[PATCH 27/42] Staging: add poch driver

[Greg Kroah-Hartman]

From: Vijay Kumar <vijaykumar@xxxxxxxxxxxx>

This is the first cut at a driver for the Redrapids Pocket Change
CardBus devices.

Receiving data seems to work properly, but overflows happen on transmit.
Still needs more hardware debugging to work properly.

(cleaned up to use proper driver core api functions by Greg)

From: Vijay Kumar <vijaykumar@xxxxxxxxxxxx>
Cc: Alexey Zaytsev <alexey.zaytsev@xxxxxxxxx>
Cc: Jaya Kumar <jayakumar.lkml@xxxxxxxxx>
Cc: Ken Sienski <sienski@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/staging/Kconfig       |    2 +
 drivers/staging/Makefile      |    1 +
 drivers/staging/poch/Kconfig  |    6 +
 drivers/staging/poch/Makefile |    1 +
 drivers/staging/poch/README   |    7 +
 drivers/staging/poch/poch.c   | 1425 +++++++++++++++++++++++++++++++++++++++++
 drivers/staging/poch/poch.h   |   29 +
 7 files changed, 1471 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/poch/Kconfig
 create mode 100644 drivers/staging/poch/Makefile
 create mode 100644 drivers/staging/poch/README
 create mode 100644 drivers/staging/poch/poch.c
 create mode 100644 drivers/staging/poch/poch.h

diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index 65a86b7..c4eff44 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -45,4 +45,6 @@ source "drivers/staging/at76_usb/Kconfig"
 
 source "drivers/staging/pcc-acpi/Kconfig"
 
+source "drivers/staging/poch/Kconfig"
+
 endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index e5c4a38..7cb8701 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -14,3 +14,4 @@ obj-$(CONFIG_PRISM2_USB)	+= wlan-ng/
 obj-$(CONFIG_ECHO)		+= echo/
 obj-$(CONFIG_USB_ATMEL)		+= at76_usb/
 obj-$(CONFIG_PCC_ACPI)		+= pcc-acpi/
+obj-$(CONFIG_POCH)		+= poch/
diff --git a/drivers/staging/poch/Kconfig b/drivers/staging/poch/Kconfig
new file mode 100644
index 0000000..b3b33b9
--- /dev/null
+++ b/drivers/staging/poch/Kconfig
@@ -0,0 +1,6 @@
+config POCH
+	tristate "Redrapids Pocket Change CardBus support"
+	depends on PCI && UIO
+	default N
+	---help---
+	  Enable support for Redrapids Pocket Change CardBus devices.
diff --git a/drivers/staging/poch/Makefile b/drivers/staging/poch/Makefile
new file mode 100644
index 0000000..d2b9680
--- /dev/null
+++ b/drivers/staging/poch/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_POCH)		+= poch.o
diff --git a/drivers/staging/poch/README b/drivers/staging/poch/README
new file mode 100644
index 0000000..f65e979
--- /dev/null
+++ b/drivers/staging/poch/README
@@ -0,0 +1,7 @@
+TODO:
+	- fix transmit overflows
+	- audit userspace interfaces
+	- get reserved major/minor if needed
+
+Please send patches to Greg Kroah-Hartman <greg@xxxxxxxxx> and
+Vijay Kumar <vijaykumar@xxxxxxxxxxxx> and Jaya Kumar <jayakumar.lkml@xxxxxxxxx>
diff --git a/drivers/staging/poch/poch.c b/drivers/staging/poch/poch.c
new file mode 100644
index 0000000..0e113f9
--- /dev/null
+++ b/drivers/staging/poch/poch.c
@@ -0,0 +1,1425 @@
+/*
+ * User-space DMA and UIO based Redrapids Pocket Change CardBus driver
+ *
+ * Copyright 2008 Vijay Kumar <vijaykumar@xxxxxxxxxxxx>
+ *
+ * Licensed under GPL version 2 only.
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/uio_driver.h>
+#include <linux/spinlock.h>
+#include <linux/cdev.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+#include <linux/poll.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/ioctl.h>
+#include <linux/io.h>
+
+#include "poch.h"
+
+#include <asm/cacheflush.h>
+
+#ifndef PCI_VENDOR_ID_RRAPIDS
+#define PCI_VENDOR_ID_RRAPIDS 0x17D2
+#endif
+
+#ifndef PCI_DEVICE_ID_RRAPIDS_POCKET_CHANGE
+#define PCI_DEVICE_ID_RRAPIDS_POCKET_CHANGE 0x0351
+#endif
+
+#define POCH_NCHANNELS 2
+
+#define MAX_POCH_CARDS 8
+#define MAX_POCH_DEVICES (MAX_POCH_CARDS * POCH_NCHANNELS)
+
+#define DRV_NAME "poch"
+#define PFX      DRV_NAME ": "
+
+/*
+ * BAR0 Bridge Register Definitions
+ */
+
+#define BRIDGE_REV_REG			0x0
+#define BRIDGE_INT_MASK_REG		0x4
+#define BRIDGE_INT_STAT_REG		0x8
+
+#define BRIDGE_INT_ACTIVE		(0x1 << 31)
+#define BRIDGE_INT_FPGA		        (0x1 << 2)
+#define BRIDGE_INT_TEMP_FAIL		(0x1 << 1)
+#define	BRIDGE_INT_TEMP_WARN		(0x1 << 0)
+
+#define BRIDGE_FPGA_RESET_REG		0xC
+
+#define BRIDGE_CARD_POWER_REG		0x10
+#define BRIDGE_CARD_POWER_EN            (0x1 << 0)
+#define BRIDGE_CARD_POWER_PROG_DONE     (0x1 << 31)
+
+#define BRIDGE_JTAG_REG			0x14
+#define BRIDGE_DMA_GO_REG		0x18
+#define BRIDGE_STAT_0_REG		0x1C
+#define BRIDGE_STAT_1_REG		0x20
+#define BRIDGE_STAT_2_REG		0x24
+#define BRIDGE_STAT_3_REG		0x28
+#define BRIDGE_TEMP_STAT_REG		0x2C
+#define BRIDGE_TEMP_THRESH_REG		0x30
+#define BRIDGE_EEPROM_REVSEL_REG	0x34
+#define BRIDGE_CIS_STRUCT_REG		0x100
+#define BRIDGE_BOARDREV_REG		0x124
+
+/*
+ * BAR1 FPGA Register Definitions
+ */
+
+#define FPGA_IFACE_REV_REG		0x0
+#define FPGA_RX_BLOCK_SIZE_REG		0x8
+#define FPGA_TX_BLOCK_SIZE_REG		0xC
+#define FPGA_RX_BLOCK_COUNT_REG		0x10
+#define FPGA_TX_BLOCK_COUNT_REG		0x14
+#define FPGA_RX_CURR_DMA_BLOCK_REG	0x18
+#define FPGA_TX_CURR_DMA_BLOCK_REG	0x1C
+#define FPGA_RX_GROUP_COUNT_REG		0x20
+#define FPGA_TX_GROUP_COUNT_REG		0x24
+#define FPGA_RX_CURR_GROUP_REG		0x28
+#define FPGA_TX_CURR_GROUP_REG		0x2C
+#define FPGA_RX_CURR_PCI_REG		0x38
+#define FPGA_TX_CURR_PCI_REG		0x3C
+#define FPGA_RX_GROUP0_START_REG	0x40
+#define FPGA_TX_GROUP0_START_REG	0xC0
+#define FPGA_DMA_DESC_1_REG		0x140
+#define FPGA_DMA_DESC_2_REG		0x144
+#define FPGA_DMA_DESC_3_REG		0x148
+#define FPGA_DMA_DESC_4_REG		0x14C
+
+#define FPGA_DMA_INT_STAT_REG		0x150
+#define FPGA_DMA_INT_MASK_REG		0x154
+#define FPGA_DMA_INT_RX		(1 << 0)
+#define FPGA_DMA_INT_TX		(1 << 1)
+
+#define FPGA_RX_GROUPS_PER_INT_REG	0x158
+#define FPGA_TX_GROUPS_PER_INT_REG	0x15C
+#define FPGA_DMA_ADR_PAGE_REG		0x160
+#define FPGA_FPGA_REV_REG		0x200
+
+#define FPGA_ADC_CLOCK_CTL_REG		0x204
+#define FPGA_ADC_CLOCK_CTL_OSC_EN	(0x1 << 3)
+#define FPGA_ADC_CLOCK_LOCAL_CLK	(0x1 | FPGA_ADC_CLOCK_CTL_OSC_EN)
+#define FPGA_ADC_CLOCK_EXT_SAMP_CLK	0X0
+
+#define FPGA_ADC_DAC_EN_REG		0x208
+#define FPGA_ADC_DAC_EN_DAC_OFF         (0x1 << 1)
+#define FPGA_ADC_DAC_EN_ADC_OFF         (0x1 << 0)
+
+#define FPGA_INT_STAT_REG		0x20C
+#define FPGA_INT_MASK_REG		0x210
+#define FPGA_INT_PLL_UNLOCKED		(0x1 << 9)
+#define FPGA_INT_DMA_CORE		(0x1 << 8)
+#define FPGA_INT_TX_FF_EMPTY		(0x1 << 7)
+#define FPGA_INT_RX_FF_EMPTY		(0x1 << 6)
+#define FPGA_INT_TX_FF_OVRFLW		(0x1 << 3)
+#define FPGA_INT_RX_FF_OVRFLW		(0x1 << 2)
+#define FPGA_INT_TX_ACQ_DONE		(0x1 << 1)
+#define FPGA_INT_RX_ACQ_DONE		(0x1)
+
+#define FPGA_RX_ADC_CTL_REG		0x214
+#define FPGA_RX_ADC_CTL_CONT_CAP	(0x0)
+#define FPGA_RX_ADC_CTL_SNAP_CAP	(0x1)
+
+#define FPGA_RX_ARM_REG			0x21C
+
+#define FPGA_DOM_REG			0x224
+#define	FPGA_DOM_DCM_RESET		(0x1 << 5)
+#define FPGA_DOM_SOFT_RESET		(0x1 << 4)
+#define FPGA_DOM_DUAL_M_SG_DMA		(0x0)
+#define FPGA_DOM_TARGET_ACCESS		(0x1)
+
+#define FPGA_TX_CTL_REG			0x228
+#define FPGA_TX_CTL_FIFO_FLUSH          (0x1 << 9)
+#define FPGA_TX_CTL_OUTPUT_ZERO         (0x0 << 2)
+#define FPGA_TX_CTL_OUTPUT_CARDBUS      (0x1 << 2)
+#define FPGA_TX_CTL_OUTPUT_ADC          (0x2 << 2)
+#define FPGA_TX_CTL_OUTPUT_SNAPSHOT     (0x3 << 2)
+#define FPGA_TX_CTL_LOOPBACK            (0x1 << 0)
+
+#define FPGA_ENDIAN_MODE_REG		0x22C
+#define FPGA_RX_FIFO_COUNT_REG		0x28C
+#define FPGA_TX_ENABLE_REG		0x298
+#define FPGA_TX_TRIGGER_REG		0x29C
+#define FPGA_TX_DATAMEM_COUNT_REG	0x2A8
+#define FPGA_CAP_FIFO_REG		0x300
+#define FPGA_TX_SNAPSHOT_REG		0x8000
+
+/*
+ * Channel Index Definitions
+ */
+
+enum {
+	CHNO_RX_CHANNEL,
+	CHNO_TX_CHANNEL,
+};
+
+struct poch_dev;
+
+enum channel_dir {
+	CHANNEL_DIR_RX,
+	CHANNEL_DIR_TX,
+};
+
+struct poch_group_info {
+	struct page *pg;
+	dma_addr_t dma_addr;
+	unsigned long user_offset;
+};
+
+struct channel_info {
+	unsigned int chno;
+
+	atomic_t sys_block_size;
+	atomic_t sys_group_size;
+	atomic_t sys_group_count;
+
+	enum channel_dir dir;
+
+	unsigned long block_size;
+	unsigned long group_size;
+	unsigned long group_count;
+
+	/* Contains the DMA address and VM offset of each group. */
+	struct poch_group_info *groups;
+
+	/* Contains the header and circular buffer exported to userspace. */
+	spinlock_t group_offsets_lock;
+	struct poch_cbuf_header *header;
+	struct page *header_pg;
+	unsigned long header_size;
+
+	/* Last group indicated as 'complete' to user space. */
+	unsigned int transfer;
+
+	wait_queue_head_t wq;
+
+	union {
+		unsigned int data_available;
+		unsigned int space_available;
+	};
+
+	void __iomem *bridge_iomem;
+	void __iomem *fpga_iomem;
+	spinlock_t *iomem_lock;
+
+	atomic_t free;
+	atomic_t inited;
+
+	/* Error counters */
+	struct poch_counters counters;
+	spinlock_t counters_lock;
+
+	struct device *dev;
+};
+
+struct poch_dev {
+	struct uio_info uio;
+	struct pci_dev *pci_dev;
+	unsigned int nchannels;
+	struct channel_info channels[POCH_NCHANNELS];
+	struct cdev cdev;
+
+	/* Counts the no. of channels that have been opened. On first
+	 * open, the card is powered on. On last channel close, the
+	 * card is powered off.
+	 */
+	atomic_t usage;
+
+	void __iomem *bridge_iomem;
+	void __iomem *fpga_iomem;
+	spinlock_t iomem_lock;
+
+	struct device *dev;
+};
+
+static dev_t poch_first_dev;
+static struct class *poch_cls;
+static DEFINE_IDR(poch_ids);
+
+static ssize_t store_block_size(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct channel_info *channel = dev_get_drvdata(dev);
+	unsigned long block_size;
+
+	sscanf(buf, "%lu", &block_size);
+	atomic_set(&channel->sys_block_size, block_size);
+
+	return count;
+}
+static DEVICE_ATTR(block_size, S_IWUSR|S_IWGRP, NULL, store_block_size);
+
+static ssize_t store_group_size(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct channel_info *channel = dev_get_drvdata(dev);
+	unsigned long group_size;
+
+	sscanf(buf, "%lu", &group_size);
+	atomic_set(&channel->sys_group_size, group_size);
+
+	return count;
+}
+static DEVICE_ATTR(group_size, S_IWUSR|S_IWGRP, NULL, store_group_size);
+
+static ssize_t store_group_count(struct device *dev,
+				struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct channel_info *channel = dev_get_drvdata(dev);
+	unsigned long group_count;
+
+	sscanf(buf, "%lu", &group_count);
+	atomic_set(&channel->sys_group_count, group_count);
+
+	return count;
+}
+static DEVICE_ATTR(group_count, S_IWUSR|S_IWGRP, NULL, store_group_count);
+
+static ssize_t show_direction(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct channel_info *channel = dev_get_drvdata(dev);
+	int len;
+
+	len = sprintf(buf, "%s\n", (channel->dir ? "tx" : "rx"));
+	return len;
+}
+static DEVICE_ATTR(dir, S_IRUSR|S_IRGRP, show_direction, NULL);
+
+static ssize_t show_mmap_size(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	struct channel_info *channel = dev_get_drvdata(dev);
+	int len;
+	unsigned long mmap_size;
+	unsigned long group_pages;
+	unsigned long header_pages;
+	unsigned long total_group_pages;
+
+	/* FIXME: We do not have to add 1, if group_size a multiple of
+	   PAGE_SIZE. */
+	group_pages = (channel->group_size / PAGE_SIZE) + 1;
+	header_pages = (channel->header_size / PAGE_SIZE) + 1;
+	total_group_pages = group_pages * channel->group_count;
+
+	mmap_size = (header_pages + total_group_pages) * PAGE_SIZE;
+	len = sprintf(buf, "%lu\n", mmap_size);
+	return len;
+}
+static DEVICE_ATTR(mmap_size, S_IRUSR|S_IRGRP, show_mmap_size, NULL);
+
+static struct device_attribute *poch_class_attrs[] = {
+	&dev_attr_block_size,
+	&dev_attr_group_size,
+	&dev_attr_group_count,
+	&dev_attr_dir,
+	&dev_attr_mmap_size,
+};
+
+static void poch_channel_free_groups(struct channel_info *channel)
+{
+	unsigned long i;
+
+	for (i = 0; i < channel->group_count; i++) {
+		struct poch_group_info *group;
+		unsigned int order;
+
+		group = &channel->groups[i];
+		order = get_order(channel->group_size);
+		if (group->pg)
+			__free_pages(group->pg, order);
+	}
+}
+
+static int poch_channel_alloc_groups(struct channel_info *channel)
+{
+	unsigned long i;
+	unsigned long group_pages;
+	unsigned long header_pages;
+
+	group_pages = (channel->group_size / PAGE_SIZE) + 1;
+	header_pages = (channel->header_size / PAGE_SIZE) + 1;
+
+	for (i = 0; i < channel->group_count; i++) {
+		struct poch_group_info *group;
+		unsigned int order;
+		gfp_t gfp_mask;
+
+		group = &channel->groups[i];
+		order = get_order(channel->group_size);
+
+		/*
+		 * __GFP_COMP is required here since we are going to
+		 * perform non-linear mapping to userspace. For more
+		 * information read the vm_insert_page() function
+		 * comments.
+		 */
+
+		gfp_mask = GFP_KERNEL | GFP_DMA32 | __GFP_ZERO;
+		group->pg = alloc_pages(gfp_mask, order);
+		if (!group->pg) {
+			poch_channel_free_groups(channel);
+			return -ENOMEM;
+		}
+
+		/* FIXME: This is the physical address not the bus
+		 * address!  This won't work in architectures that
+		 * have an IOMMU. Can we use pci_map_single() for
+		 * this?
+		 */
+		group->dma_addr = page_to_pfn(group->pg) * PAGE_SIZE;
+		group->user_offset =
+			(header_pages + (i * group_pages)) * PAGE_SIZE;
+
+		printk(KERN_INFO PFX "%ld: user_offset: 0x%lx dma: 0x%x\n", i,
+		       group->user_offset, group->dma_addr);
+	}
+
+	return 0;
+}
+
+static void channel_latch_attr(struct channel_info *channel)
+{
+	channel->group_count = atomic_read(&channel->sys_group_count);
+	channel->group_size = atomic_read(&channel->sys_group_size);
+	channel->block_size = atomic_read(&channel->sys_block_size);
+}
+
+/*
+ * Configure DMA group registers
+ */
+static void channel_dma_init(struct channel_info *channel)
+{
+	void __iomem *fpga = channel->fpga_iomem;
+	u32 group_regs_base;
+	u32 group_reg;
+	unsigned int page;
+	unsigned int group_in_page;
+	unsigned long i;
+	u32 block_size_reg;
+	u32 block_count_reg;
+	u32 group_count_reg;
+	u32 groups_per_int_reg;
+	u32 curr_pci_reg;
+
+	if (channel->chno == CHNO_RX_CHANNEL) {
+		group_regs_base = FPGA_RX_GROUP0_START_REG;
+		block_size_reg = FPGA_RX_BLOCK_SIZE_REG;
+		block_count_reg = FPGA_RX_BLOCK_COUNT_REG;
+		group_count_reg = FPGA_RX_GROUP_COUNT_REG;
+		groups_per_int_reg = FPGA_RX_GROUPS_PER_INT_REG;
+		curr_pci_reg = FPGA_RX_CURR_PCI_REG;
+	} else {
+		group_regs_base = FPGA_TX_GROUP0_START_REG;
+		block_size_reg = FPGA_TX_BLOCK_SIZE_REG;
+		block_count_reg = FPGA_TX_BLOCK_COUNT_REG;
+		group_count_reg = FPGA_TX_GROUP_COUNT_REG;
+		groups_per_int_reg = FPGA_TX_GROUPS_PER_INT_REG;
+		curr_pci_reg = FPGA_TX_CURR_PCI_REG;
+	}
+
+	printk(KERN_WARNING "block_size, group_size, group_count\n");
+	iowrite32(channel->block_size, fpga + block_size_reg);
+	iowrite32(channel->group_size / channel->block_size,
+		  fpga + block_count_reg);
+	iowrite32(channel->group_count, fpga + group_count_reg);
+	/* FIXME: Hardcoded groups per int. Get it from sysfs? */
+	iowrite32(1, fpga + groups_per_int_reg);
+
+	/* Unlock PCI address? Not defined in the data sheet, but used
+	 * in the reference code by Redrapids.
+	 */
+	iowrite32(0x1, fpga + curr_pci_reg);
+
+	/* The DMA address page register is shared between the RX and
+	 * TX channels, so acquire lock.
+	 */
+	spin_lock(channel->iomem_lock);
+	for (i = 0; i < channel->group_count; i++) {
+		page = i / 32;
+		group_in_page = i % 32;
+
+		group_reg = group_regs_base + (group_in_page * 4);
+
+		iowrite32(page, fpga + FPGA_DMA_ADR_PAGE_REG);
+		iowrite32(channel->groups[i].dma_addr, fpga + group_reg);
+	}
+	for (i = 0; i < channel->group_count; i++) {
+		page = i / 32;
+		group_in_page = i % 32;
+
+		group_reg = group_regs_base + (group_in_page * 4);
+
+		iowrite32(page, fpga + FPGA_DMA_ADR_PAGE_REG);
+		printk(KERN_INFO PFX "%ld: read dma_addr: 0x%x\n", i,
+		       ioread32(fpga + group_reg));
+	}
+	spin_unlock(channel->iomem_lock);
+
+}
+
+static int poch_channel_alloc_header(struct channel_info *channel)
+{
+	struct poch_cbuf_header *header = channel->header;
+	unsigned long group_offset_size;
+	unsigned long tot_group_offsets_size;
+
+	/* Allocate memory to hold header exported userspace */
+	group_offset_size = sizeof(header->group_offsets[0]);
+	tot_group_offsets_size = group_offset_size * channel->group_count;
+	channel->header_size = sizeof(*header) + tot_group_offsets_size;
+	channel->header_pg = alloc_pages(GFP_KERNEL | __GFP_ZERO,
+					 get_order(channel->header_size));
+	if (!channel->header_pg)
+		return -ENOMEM;
+
+	channel->header = page_address(channel->header_pg);
+
+	return 0;
+}
+
+static void poch_channel_free_header(struct channel_info *channel)
+{
+	unsigned int order;
+
+	order = get_order(channel->header_size);
+	__free_pages(channel->header_pg, order);
+}
+
+static void poch_channel_init_header(struct channel_info *channel)
+{
+	int i;
+	struct poch_group_info *groups;
+	s32 *group_offsets;
+
+	channel->header->group_size_bytes = channel->group_size;
+	channel->header->group_count = channel->group_count;
+
+	spin_lock_init(&channel->group_offsets_lock);
+
+	group_offsets = channel->header->group_offsets;
+	groups = channel->groups;
+
+	for (i = 0; i < channel->group_count; i++) {
+		if (channel->dir == CHANNEL_DIR_RX)
+			group_offsets[i] = -1;
+		else
+			group_offsets[i] = groups[i].user_offset;
+	}
+}
+
+static void __poch_channel_clear_counters(struct channel_info *channel)
+{
+	channel->counters.pll_unlock = 0;
+	channel->counters.fifo_empty = 0;
+	channel->counters.fifo_overflow = 0;
+}
+
+static int poch_channel_init(struct channel_info *channel,
+			     struct poch_dev *poch_dev)
+{
+	struct pci_dev *pdev = poch_dev->pci_dev;
+	struct device *dev = &pdev->dev;
+	unsigned long alloc_size;
+	int ret;
+
+	printk(KERN_WARNING "channel_latch_attr\n");
+
+	channel_latch_attr(channel);
+
+	channel->transfer = 0;
+
+	/* Allocate memory to hold group information. */
+	alloc_size = channel->group_count * sizeof(struct poch_group_info);
+	channel->groups = kzalloc(alloc_size, GFP_KERNEL);
+	if (!channel->groups) {
+		dev_err(dev, "error allocating memory for group info\n");
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	printk(KERN_WARNING "poch_channel_alloc_groups\n");
+
+	ret = poch_channel_alloc_groups(channel);
+	if (ret) {
+		dev_err(dev, "error allocating groups of order %d\n",
+			get_order(channel->group_size));
+		goto out_free_group_info;
+	}
+
+	ret = poch_channel_alloc_header(channel);
+	if (ret) {
+		dev_err(dev, "error allocating user space header\n");
+		goto out_free_groups;
+	}
+
+	channel->fpga_iomem = poch_dev->fpga_iomem;
+	channel->bridge_iomem = poch_dev->bridge_iomem;
+	channel->iomem_lock = &poch_dev->iomem_lock;
+	spin_lock_init(&channel->counters_lock);
+
+	__poch_channel_clear_counters(channel);
+
+	printk(KERN_WARNING "poch_channel_init_header\n");
+
+	poch_channel_init_header(channel);
+
+	return 0;
+
+ out_free_groups:
+	poch_channel_free_groups(channel);
+ out_free_group_info:
+	kfree(channel->groups);
+ out:
+	return ret;
+}
+
+static int poch_wait_fpga_prog(void __iomem *bridge)
+{
+	unsigned long total_wait;
+	const unsigned long wait_period = 100;
+	/* FIXME: Get the actual timeout */
+	const unsigned long prog_timeo = 10000; /* 10 Seconds */
+	u32 card_power;
+
+	printk(KERN_WARNING "poch_wait_fpg_prog\n");
+
+	printk(KERN_INFO PFX "programming fpga ...\n");
+	total_wait = 0;
+	while (1) {
+		msleep(wait_period);
+		total_wait += wait_period;
+
+		card_power = ioread32(bridge + BRIDGE_CARD_POWER_REG);
+		if (card_power & BRIDGE_CARD_POWER_PROG_DONE) {
+			printk(KERN_INFO PFX "programming done\n");
+			return 0;
+		}
+		if (total_wait > prog_timeo) {
+			printk(KERN_ERR PFX
+			       "timed out while programming FPGA\n");
+			return -EIO;
+		}
+	}
+}
+
+static void poch_card_power_off(struct poch_dev *poch_dev)
+{
+	void __iomem *bridge = poch_dev->bridge_iomem;
+	u32 card_power;
+
+	iowrite32(0, bridge + BRIDGE_INT_MASK_REG);
+	iowrite32(0, bridge + BRIDGE_DMA_GO_REG);
+
+	card_power = ioread32(bridge + BRIDGE_CARD_POWER_REG);
+	iowrite32(card_power & ~BRIDGE_CARD_POWER_EN,
+		  bridge + BRIDGE_CARD_POWER_REG);
+}
+
+enum clk_src {
+	CLK_SRC_ON_BOARD,
+	CLK_SRC_EXTERNAL
+};
+
+static void poch_card_clock_on(void __iomem *fpga)
+{
+	/* FIXME: Get this data through sysfs? */
+	enum clk_src clk_src = CLK_SRC_ON_BOARD;
+
+	if (clk_src == CLK_SRC_ON_BOARD) {
+		iowrite32(FPGA_ADC_CLOCK_LOCAL_CLK | FPGA_ADC_CLOCK_CTL_OSC_EN,
+			  fpga + FPGA_ADC_CLOCK_CTL_REG);
+	} else if (clk_src == CLK_SRC_EXTERNAL) {
+		iowrite32(FPGA_ADC_CLOCK_EXT_SAMP_CLK,
+			  fpga + FPGA_ADC_CLOCK_CTL_REG);
+	}
+}
+
+static int poch_card_power_on(struct poch_dev *poch_dev)
+{
+	void __iomem *bridge = poch_dev->bridge_iomem;
+	void __iomem *fpga = poch_dev->fpga_iomem;
+
+	iowrite32(BRIDGE_CARD_POWER_EN, bridge + BRIDGE_CARD_POWER_REG);
+
+	if (poch_wait_fpga_prog(bridge) != 0) {
+		poch_card_power_off(poch_dev);
+		return -EIO;
+	}
+
+	poch_card_clock_on(fpga);
+
+	/* Sync to new clock, reset state machines, set DMA mode. */
+	iowrite32(FPGA_DOM_DCM_RESET | FPGA_DOM_SOFT_RESET
+		  | FPGA_DOM_DUAL_M_SG_DMA, fpga + FPGA_DOM_REG);
+
+	/* FIXME: The time required for sync. needs to be tuned. */
+	msleep(1000);
+
+	return 0;
+}
+
+static void poch_channel_analog_on(struct channel_info *channel)
+{
+	void __iomem *fpga = channel->fpga_iomem;
+	u32 adc_dac_en;
+
+	spin_lock(channel->iomem_lock);
+	adc_dac_en = ioread32(fpga + FPGA_ADC_DAC_EN_REG);
+	switch (channel->chno) {
+	case CHNO_RX_CHANNEL:
+		iowrite32(adc_dac_en & ~FPGA_ADC_DAC_EN_ADC_OFF,
+			  fpga + FPGA_ADC_DAC_EN_REG);
+		break;
+	case CHNO_TX_CHANNEL:
+		iowrite32(adc_dac_en & ~FPGA_ADC_DAC_EN_DAC_OFF,
+			  fpga + FPGA_ADC_DAC_EN_REG);
+		break;
+	}
+	spin_unlock(channel->iomem_lock);
+}
+
+static int poch_open(struct inode *inode, struct file *filp)
+{
+	struct poch_dev *poch_dev;
+	struct channel_info *channel;
+	void __iomem *bridge;
+	void __iomem *fpga;
+	int chno;
+	int usage;
+	int ret;
+
+	poch_dev = container_of(inode->i_cdev, struct poch_dev, cdev);
+	bridge = poch_dev->bridge_iomem;
+	fpga = poch_dev->fpga_iomem;
+
+	chno = iminor(inode) % poch_dev->nchannels;
+	channel = &poch_dev->channels[chno];
+
+	if (!atomic_dec_and_test(&channel->free)) {
+		atomic_inc(&channel->free);
+		ret = -EBUSY;
+		goto out;
+	}
+
+	usage = atomic_inc_return(&poch_dev->usage);
+
+	printk(KERN_WARNING "poch_card_power_on\n");
+
+	if (usage == 1) {
+		ret = poch_card_power_on(poch_dev);
+		if (ret)
+			goto out_dec_usage;
+	}
+
+	printk(KERN_INFO "CardBus Bridge Revision: %x\n",
+	       ioread32(bridge + BRIDGE_REV_REG));
+	printk(KERN_INFO "CardBus Interface Revision: %x\n",
+	       ioread32(fpga + FPGA_IFACE_REV_REG));
+
+	channel->chno = chno;
+	filp->private_data = channel;
+
+	printk(KERN_WARNING "poch_channel_init\n");
+
+	ret = poch_channel_init(channel, poch_dev);
+	if (ret)
+		goto out_power_off;
+
+	poch_channel_analog_on(channel);
+
+	printk(KERN_WARNING "channel_dma_init\n");
+
+	channel_dma_init(channel);
+
+	printk(KERN_WARNING "poch_channel_analog_on\n");
+
+	if (usage == 1) {
+		printk(KERN_WARNING "setting up DMA\n");
+
+		/* Initialize DMA Controller. */
+		iowrite32(FPGA_CAP_FIFO_REG, bridge + BRIDGE_STAT_2_REG);
+		iowrite32(FPGA_DMA_DESC_1_REG, bridge + BRIDGE_STAT_3_REG);
+
+		ioread32(fpga + FPGA_DMA_INT_STAT_REG);
+		ioread32(fpga + FPGA_INT_STAT_REG);
+		ioread32(bridge + BRIDGE_INT_STAT_REG);
+
+		/* Initialize Interrupts. FIXME: Enable temperature
+		 * handling We are enabling both Tx and Rx channel
+		 * interrupts here. Do we need to enable interrupts
+		 * only for the current channel? Anyways we won't get
+		 * the interrupt unless the DMA is activated.
+		 */
+		iowrite32(BRIDGE_INT_FPGA, bridge + BRIDGE_INT_MASK_REG);
+		iowrite32(FPGA_INT_DMA_CORE
+			  | FPGA_INT_PLL_UNLOCKED
+			  | FPGA_INT_TX_FF_EMPTY
+			  | FPGA_INT_RX_FF_EMPTY
+			  | FPGA_INT_TX_FF_OVRFLW
+			  | FPGA_INT_RX_FF_OVRFLW,
+			  fpga + FPGA_INT_MASK_REG);
+		iowrite32(FPGA_DMA_INT_RX | FPGA_DMA_INT_TX,
+			  fpga + FPGA_DMA_INT_MASK_REG);
+	}
+
+	if (channel->dir == CHANNEL_DIR_TX) {
+		/* Flush TX FIFO and output data from cardbus. */
+		iowrite32(FPGA_TX_CTL_FIFO_FLUSH
+			  | FPGA_TX_CTL_OUTPUT_CARDBUS,
+			  fpga + FPGA_TX_CTL_REG);
+	}
+
+	atomic_inc(&channel->inited);
+
+	return 0;
+
+ out_power_off:
+	if (usage == 1)
+		poch_card_power_off(poch_dev);
+ out_dec_usage:
+	atomic_dec(&poch_dev->usage);
+	atomic_inc(&channel->free);
+ out:
+	return ret;
+}
+
+static int poch_release(struct inode *inode, struct file *filp)
+{
+	struct channel_info *channel = filp->private_data;
+	struct poch_dev *poch_dev;
+	int usage;
+
+	poch_dev = container_of(inode->i_cdev, struct poch_dev, cdev);
+
+	usage = atomic_dec_return(&poch_dev->usage);
+	if (usage == 0) {
+		printk(KERN_WARNING "poch_card_power_off\n");
+		poch_card_power_off(poch_dev);
+	}
+
+	atomic_dec(&channel->inited);
+	poch_channel_free_header(channel);
+	poch_channel_free_groups(channel);
+	kfree(channel->groups);
+	atomic_inc(&channel->free);
+
+	return 0;
+}
+
+/*
+ * Map the header and the group buffers, to user space.
+ */
+static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct channel_info *channel = filp->private_data;
+
+	unsigned long start;
+	unsigned long size;
+
+	unsigned long group_pages;
+	unsigned long header_pages;
+	unsigned long total_group_pages;
+
+	int pg_num;
+	struct page *pg;
+
+	int i;
+	int ret;
+
+	printk(KERN_WARNING "poch_mmap\n");
+
+	if (vma->vm_pgoff) {
+		printk(KERN_WARNING PFX "page offset: %lu\n", vma->vm_pgoff);
+		return -EINVAL;
+	}
+
+	group_pages = (channel->group_size / PAGE_SIZE) + 1;
+	header_pages = (channel->header_size / PAGE_SIZE) + 1;
+	total_group_pages = group_pages * channel->group_count;
+
+	size = vma->vm_end - vma->vm_start;
+	if (size != (header_pages + total_group_pages) * PAGE_SIZE) {
+		printk(KERN_WARNING PFX "required %lu bytes\n", size);
+		return -EINVAL;
+	}
+
+	start = vma->vm_start;
+
+	/* FIXME: Cleanup required on failure? */
+	pg = channel->header_pg;
+	for (pg_num = 0; pg_num < header_pages; pg_num++, pg++) {
+		printk(KERN_DEBUG PFX "page_count: %d\n", page_count(pg));
+		printk(KERN_DEBUG PFX "%d: header: 0x%lx\n", pg_num, start);
+		ret = vm_insert_page(vma, start, pg);
+		if (ret) {
+			printk(KERN_DEBUG "vm_insert 1 failed at %lx\n", start);
+			return ret;
+		}
+		start += PAGE_SIZE;
+	}
+
+	for (i = 0; i < channel->group_count; i++) {
+		pg = channel->groups[i].pg;
+		for (pg_num = 0; pg_num < group_pages; pg_num++, pg++) {
+			printk(KERN_DEBUG PFX "%d: group %d: 0x%lx\n",
+			       pg_num, i, start);
+			ret = vm_insert_page(vma, start, pg);
+			if (ret) {
+				printk(KERN_DEBUG PFX
+				       "vm_insert 2 failed at %d\n", pg_num);
+				return ret;
+			}
+			start += PAGE_SIZE;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Check whether there is some group that the user space has not
+ * consumed yet. When the user space consumes a group, it sets it to
+ * -1. Cosuming could be reading data in case of RX and filling a
+ * buffer in case of TX.
+ */
+static int poch_channel_available(struct channel_info *channel)
+{
+	int i;
+
+	spin_lock_irq(&channel->group_offsets_lock);
+
+	for (i = 0; i < channel->group_count; i++) {
+		if (channel->dir == CHANNEL_DIR_RX
+		    && channel->header->group_offsets[i] == -1) {
+			spin_unlock_irq(&channel->group_offsets_lock);
+			return 1;
+		}
+
+		if (channel->dir == CHANNEL_DIR_TX
+		    && channel->header->group_offsets[i] != -1) {
+			spin_unlock_irq(&channel->group_offsets_lock);
+			return 1;
+		}
+	}
+
+	spin_unlock_irq(&channel->group_offsets_lock);
+
+	return 0;
+}
+
+static unsigned int poch_poll(struct file *filp, poll_table *pt)
+{
+	struct channel_info *channel = filp->private_data;
+	unsigned int ret = 0;
+
+	poll_wait(filp, &channel->wq, pt);
+
+	if (poch_channel_available(channel)) {
+		if (channel->dir == CHANNEL_DIR_RX)
+			ret = POLLIN | POLLRDNORM;
+		else
+			ret = POLLOUT | POLLWRNORM;
+	}
+
+	return ret;
+}
+
+static int poch_ioctl(struct inode *inode, struct file *filp,
+		      unsigned int cmd, unsigned long arg)
+{
+	struct channel_info *channel = filp->private_data;
+	void __iomem *fpga = channel->fpga_iomem;
+	void __iomem *bridge = channel->bridge_iomem;
+	void __user *argp = (void __user *)arg;
+	struct vm_area_struct *vms;
+	struct poch_counters counters;
+	int ret;
+
+	switch (cmd) {
+	case POCH_IOC_TRANSFER_START:
+		switch (channel->chno) {
+		case CHNO_TX_CHANNEL:
+			printk(KERN_INFO PFX "ioctl: Tx start\n");
+			iowrite32(0x1, fpga + FPGA_TX_TRIGGER_REG);
+			iowrite32(0x1, fpga + FPGA_TX_ENABLE_REG);
+
+			/* FIXME: Does it make sense to do a DMA GO
+			 * twice, once in Tx and once in Rx.
+			 */
+			iowrite32(0x1, bridge + BRIDGE_DMA_GO_REG);
+			break;
+		case CHNO_RX_CHANNEL:
+			printk(KERN_INFO PFX "ioctl: Rx start\n");
+			iowrite32(0x1, fpga + FPGA_RX_ARM_REG);
+			iowrite32(0x1, bridge + BRIDGE_DMA_GO_REG);
+			break;
+		}
+		break;
+	case POCH_IOC_TRANSFER_STOP:
+		switch (channel->chno) {
+		case CHNO_TX_CHANNEL:
+			printk(KERN_INFO PFX "ioctl: Tx stop\n");
+			iowrite32(0x0, fpga + FPGA_TX_ENABLE_REG);
+			iowrite32(0x0, fpga + FPGA_TX_TRIGGER_REG);
+			iowrite32(0x0, bridge + BRIDGE_DMA_GO_REG);
+			break;
+		case CHNO_RX_CHANNEL:
+			printk(KERN_INFO PFX "ioctl: Rx stop\n");
+			iowrite32(0x0, fpga + FPGA_RX_ARM_REG);
+			iowrite32(0x0, bridge + BRIDGE_DMA_GO_REG);
+			break;
+		}
+		break;
+	case POCH_IOC_GET_COUNTERS:
+		if (access_ok(VERIFY_WRITE, argp, sizeof(struct poch_counters)))
+			return -EFAULT;
+
+		spin_lock_irq(&channel->counters_lock);
+		counters = channel->counters;
+		__poch_channel_clear_counters(channel);
+		spin_unlock_irq(&channel->counters_lock);
+
+		ret = copy_to_user(argp, &counters,
+				   sizeof(struct poch_counters));
+		if (ret)
+			return ret;
+
+		break;
+	case POCH_IOC_SYNC_GROUP_FOR_USER:
+	case POCH_IOC_SYNC_GROUP_FOR_DEVICE:
+		vms = find_vma(current->mm, arg);
+		if (!vms)
+			/* Address not mapped. */
+			return -EINVAL;
+		if (vms->vm_file != filp)
+			/* Address mapped from different device/file. */
+			return -EINVAL;
+
+		flush_cache_range(vms, arg, arg + channel->group_size);
+		break;
+	}
+	return 0;
+}
+
+static struct file_operations poch_fops = {
+	.owner = THIS_MODULE,
+	.open = poch_open,
+	.release = poch_release,
+	.ioctl = poch_ioctl,
+	.poll = poch_poll,
+	.mmap = poch_mmap
+};
+
+static void poch_irq_dma(struct channel_info *channel)
+{
+	u32 prev_transfer;
+	u32 curr_transfer;
+	long groups_done;
+	unsigned long i, j;
+	struct poch_group_info *groups;
+	s32 *group_offsets;
+	u32 curr_group_reg;
+
+	if (!atomic_read(&channel->inited))
+		return;
+
+	prev_transfer = channel->transfer;
+
+	if (channel->chno == CHNO_RX_CHANNEL)
+		curr_group_reg = FPGA_RX_CURR_GROUP_REG;
+	else
+		curr_group_reg = FPGA_TX_CURR_GROUP_REG;
+
+	curr_transfer = ioread32(channel->fpga_iomem + curr_group_reg);
+
+	groups_done = curr_transfer - prev_transfer;
+	/* Check wrap over, and handle it. */
+	if (groups_done <= 0)
+		groups_done += channel->group_count;
+
+	group_offsets = channel->header->group_offsets;
+	groups = channel->groups;
+
+	spin_lock(&channel->group_offsets_lock);
+
+	for (i = 0; i < groups_done; i++) {
+		j = (prev_transfer + i) % channel->group_count;
+		if (channel->dir == CHANNEL_DIR_RX)
+			group_offsets[j] = -1;
+		else
+			group_offsets[j] = groups[j].user_offset;
+	}
+
+	spin_unlock(&channel->group_offsets_lock);
+
+	channel->transfer = curr_transfer;
+
+	wake_up_interruptible(&channel->wq);
+}
+
+static irqreturn_t poch_irq_handler(int irq, void *p)
+{
+	struct poch_dev *poch_dev = p;
+	void __iomem *bridge = poch_dev->bridge_iomem;
+	void __iomem *fpga = poch_dev->fpga_iomem;
+	struct channel_info *channel_rx = &poch_dev->channels[CHNO_RX_CHANNEL];
+	struct channel_info *channel_tx = &poch_dev->channels[CHNO_TX_CHANNEL];
+	u32 bridge_stat;
+	u32 fpga_stat;
+	u32 dma_stat;
+
+	bridge_stat = ioread32(bridge + BRIDGE_INT_STAT_REG);
+	fpga_stat = ioread32(fpga + FPGA_INT_STAT_REG);
+	dma_stat = ioread32(fpga + FPGA_DMA_INT_STAT_REG);
+
+	ioread32(fpga + FPGA_DMA_INT_STAT_REG);
+	ioread32(fpga + FPGA_INT_STAT_REG);
+	ioread32(bridge + BRIDGE_INT_STAT_REG);
+
+	if (bridge_stat & BRIDGE_INT_FPGA) {
+		if (fpga_stat & FPGA_INT_DMA_CORE) {
+			if (dma_stat & FPGA_DMA_INT_RX)
+				poch_irq_dma(channel_rx);
+			if (dma_stat & FPGA_DMA_INT_TX)
+				poch_irq_dma(channel_tx);
+		}
+		if (fpga_stat & FPGA_INT_PLL_UNLOCKED) {
+			channel_tx->counters.pll_unlock++;
+			channel_rx->counters.pll_unlock++;
+			if (printk_ratelimit())
+				printk(KERN_WARNING PFX "PLL unlocked\n");
+		}
+		if (fpga_stat & FPGA_INT_TX_FF_EMPTY)
+			channel_tx->counters.fifo_empty++;
+		if (fpga_stat & FPGA_INT_TX_FF_OVRFLW)
+			channel_tx->counters.fifo_overflow++;
+		if (fpga_stat & FPGA_INT_RX_FF_EMPTY)
+			channel_rx->counters.fifo_empty++;
+		if (fpga_stat & FPGA_INT_RX_FF_OVRFLW)
+			channel_rx->counters.fifo_overflow++;
+
+		/*
+		 * FIXME: These errors should be notified through the
+		 * poll interface as POLLERR.
+		 */
+
+		/* Re-enable interrupts. */
+		iowrite32(BRIDGE_INT_FPGA, bridge + BRIDGE_INT_MASK_REG);
+
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static void poch_class_dev_unregister(struct poch_dev *poch_dev, int id)
+{
+	int i, j;
+	int nattrs;
+	struct channel_info *channel;
+	dev_t devno;
+
+	if (poch_dev->dev == NULL)
+		return;
+
+	for (i = 0; i < poch_dev->nchannels; i++) {
+		channel = &poch_dev->channels[i];
+		devno = poch_first_dev + (id * poch_dev->nchannels) + i;
+
+		if (!channel->dev)
+			continue;
+
+		nattrs = sizeof(poch_class_attrs)/sizeof(poch_class_attrs[0]);
+		for (j = 0; j < nattrs; j++)
+			device_remove_file(channel->dev, poch_class_attrs[j]);
+
+		device_unregister(channel->dev);
+	}
+
+	device_unregister(poch_dev->dev);
+}
+
+static int __devinit poch_class_dev_register(struct poch_dev *poch_dev,
+					     int id)
+{
+	struct device *dev = &poch_dev->pci_dev->dev;
+	int i, j;
+	int nattrs;
+	int ret;
+	struct channel_info *channel;
+	dev_t devno;
+
+	poch_dev->dev = device_create(poch_cls, &poch_dev->pci_dev->dev,
+				      MKDEV(0, 0), NULL, "poch%d", id);
+	if (IS_ERR(poch_dev->dev)) {
+		dev_err(dev, "error creating parent class device");
+		ret = PTR_ERR(poch_dev->dev);
+		poch_dev->dev = NULL;
+		return ret;
+	}
+
+	for (i = 0; i < poch_dev->nchannels; i++) {
+		channel = &poch_dev->channels[i];
+
+		devno = poch_first_dev + (id * poch_dev->nchannels) + i;
+		channel->dev = device_create(poch_cls, poch_dev->dev, devno,
+					     NULL, "ch%d", i);
+		if (IS_ERR(channel->dev)) {
+			dev_err(dev, "error creating channel class device");
+			ret = PTR_ERR(channel->dev);
+			channel->dev = NULL;
+			poch_class_dev_unregister(poch_dev, id);
+			return ret;
+		}
+
+		dev_set_drvdata(channel->dev, channel);
+		nattrs = sizeof(poch_class_attrs)/sizeof(poch_class_attrs[0]);
+		for (j = 0; j < nattrs; j++) {
+			ret = device_create_file(channel->dev,
+						 poch_class_attrs[j]);
+			if (ret) {
+				dev_err(dev, "error creating attribute file");
+				poch_class_dev_unregister(poch_dev, id);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int __devinit poch_pci_probe(struct pci_dev *pdev,
+				    const struct pci_device_id *pci_id)
+{
+	struct device *dev = &pdev->dev;
+	struct poch_dev *poch_dev;
+	struct uio_info *uio;
+	int ret;
+	int id;
+	int i;
+
+	poch_dev = kzalloc(sizeof(struct poch_dev), GFP_KERNEL);
+	if (!poch_dev) {
+		dev_err(dev, "error allocating priv. data memory\n");
+		return -ENOMEM;
+	}
+
+	poch_dev->pci_dev = pdev;
+	uio = &poch_dev->uio;
+
+	pci_set_drvdata(pdev, poch_dev);
+
+	spin_lock_init(&poch_dev->iomem_lock);
+
+	poch_dev->nchannels = POCH_NCHANNELS;
+	poch_dev->channels[CHNO_RX_CHANNEL].dir = CHANNEL_DIR_RX;
+	poch_dev->channels[CHNO_TX_CHANNEL].dir = CHANNEL_DIR_TX;
+
+	for (i = 0; i < poch_dev->nchannels; i++) {
+		init_waitqueue_head(&poch_dev->channels[i].wq);
+		atomic_set(&poch_dev->channels[i].free, 1);
+		atomic_set(&poch_dev->channels[i].inited, 0);
+	}
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		dev_err(dev, "error enabling device\n");
+		goto out_free;
+	}
+
+	ret = pci_request_regions(pdev, "poch");
+	if (ret) {
+		dev_err(dev, "error requesting resources\n");
+		goto out_disable;
+	}
+
+	uio->mem[0].addr = pci_resource_start(pdev, 1);
+	if (!uio->mem[0].addr) {
+		dev_err(dev, "invalid BAR1\n");
+		ret = -ENODEV;
+		goto out_release;
+	}
+
+	uio->mem[0].size = pci_resource_len(pdev, 1);
+	uio->mem[0].memtype = UIO_MEM_PHYS;
+
+	uio->name = "poch";
+	uio->version = "0.0.1";
+	uio->irq = -1;
+	ret = uio_register_device(dev, uio);
+	if (ret) {
+		dev_err(dev, "error register UIO device: %d\n", ret);
+		goto out_release;
+	}
+
+	poch_dev->bridge_iomem = ioremap(pci_resource_start(pdev, 0),
+					 pci_resource_len(pdev, 0));
+	if (poch_dev->bridge_iomem == NULL) {
+		dev_err(dev, "error mapping bridge (bar0) registers\n");
+		ret = -ENOMEM;
+		goto out_uio_unreg;
+	}
+
+	poch_dev->fpga_iomem = ioremap(pci_resource_start(pdev, 1),
+				       pci_resource_len(pdev, 1));
+	if (poch_dev->fpga_iomem == NULL) {
+		dev_err(dev, "error mapping fpga (bar1) registers\n");
+		ret = -ENOMEM;
+		goto out_bar0_unmap;
+	}
+
+	ret = request_irq(pdev->irq, poch_irq_handler, IRQF_SHARED,
+			  dev->bus_id, poch_dev);
+	if (ret) {
+		dev_err(dev, "error requesting IRQ %u\n", pdev->irq);
+		ret = -ENOMEM;
+		goto out_bar1_unmap;
+	}
+
+	if (!idr_pre_get(&poch_ids, GFP_KERNEL)) {
+		dev_err(dev, "error allocating memory ids\n");
+		ret = -ENOMEM;
+		goto out_free_irq;
+	}
+
+	idr_get_new(&poch_ids, poch_dev, &id);
+	if (id >= MAX_POCH_CARDS) {
+		dev_err(dev, "minors exhausted\n");
+		ret = -EBUSY;
+		goto out_free_irq;
+	}
+
+	cdev_init(&poch_dev->cdev, &poch_fops);
+	poch_dev->cdev.owner = THIS_MODULE;
+	ret = cdev_add(&poch_dev->cdev,
+		       poch_first_dev + (id * poch_dev->nchannels),
+		       poch_dev->nchannels);
+	if (ret) {
+		dev_err(dev, "error register character device\n");
+		goto out_idr_remove;
+	}
+
+	ret = poch_class_dev_register(poch_dev, id);
+	if (ret)
+		goto out_cdev_del;
+
+	return 0;
+
+ out_cdev_del:
+	cdev_del(&poch_dev->cdev);
+ out_idr_remove:
+	idr_remove(&poch_ids, id);
+ out_free_irq:
+	free_irq(pdev->irq, poch_dev);
+ out_bar1_unmap:
+	iounmap(poch_dev->fpga_iomem);
+ out_bar0_unmap:
+	iounmap(poch_dev->bridge_iomem);
+ out_uio_unreg:
+	uio_unregister_device(uio);
+ out_release:
+	pci_release_regions(pdev);
+ out_disable:
+	pci_disable_device(pdev);
+ out_free:
+	kfree(poch_dev);
+	return ret;
+}
+
+/*
+ * FIXME: We are yet to handle the hot unplug case.
+ */
+static void poch_pci_remove(struct pci_dev *pdev)
+{
+	struct poch_dev *poch_dev = pci_get_drvdata(pdev);
+	struct uio_info *uio = &poch_dev->uio;
+	unsigned int minor = MINOR(poch_dev->cdev.dev);
+	unsigned int id = minor / poch_dev->nchannels;
+
+	/* FIXME: unmap fpga_iomem and bridge_iomem */
+
+	poch_class_dev_unregister(poch_dev, id);
+	cdev_del(&poch_dev->cdev);
+	idr_remove(&poch_ids, id);
+	free_irq(pdev->irq, poch_dev);
+	uio_unregister_device(uio);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	pci_set_drvdata(pdev, NULL);
+	iounmap(uio->mem[0].internal_addr);
+
+	kfree(poch_dev);
+}
+
+static const struct pci_device_id poch_pci_ids[] /* __devinitconst */ = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_RRAPIDS,
+		     PCI_DEVICE_ID_RRAPIDS_POCKET_CHANGE) },
+	{ 0, }
+};
+
+static struct pci_driver poch_pci_driver = {
+	.name = DRV_NAME,
+	.id_table = poch_pci_ids,
+	.probe = poch_pci_probe,
+	.remove = poch_pci_remove,
+};
+
+static int __init poch_init_module(void)
+{
+	int ret = 0;
+
+	ret = alloc_chrdev_region(&poch_first_dev, 0,
+				  MAX_POCH_DEVICES, DRV_NAME);
+	if (ret) {
+		printk(KERN_ERR PFX "error allocating device no.");
+		return ret;
+	}
+
+	poch_cls = class_create(THIS_MODULE, "pocketchange");
+	if (IS_ERR(poch_cls)) {
+		ret = PTR_ERR(poch_cls);
+		goto out_unreg_chrdev;
+	}
+
+	ret = pci_register_driver(&poch_pci_driver);
+	if (ret) {
+		printk(KERN_ERR PFX "error register PCI device");
+		goto out_class_destroy;
+	}
+
+	return 0;
+
+ out_class_destroy:
+	class_destroy(poch_cls);
+
+ out_unreg_chrdev:
+	unregister_chrdev_region(poch_first_dev, MAX_POCH_DEVICES);
+
+	return ret;
+}
+
+static void __exit poch_exit_module(void)
+{
+	pci_unregister_driver(&poch_pci_driver);
+	class_destroy(poch_cls);
+	unregister_chrdev_region(poch_first_dev, MAX_POCH_DEVICES);
+}
+
+module_init(poch_init_module);
+module_exit(poch_exit_module);
+
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/poch/poch.h b/drivers/staging/poch/poch.h
new file mode 100644
index 0000000..51a2d14
--- /dev/null
+++ b/drivers/staging/poch/poch.h
@@ -0,0 +1,29 @@
+/*
+ * User-space DMA and UIO based Redrapids Pocket Change CardBus driver
+ *
+ * Copyright 2008 Vijay Kumar <vijaykumar@xxxxxxxxxxxx>
+ *
+ * Part of userspace API. Should be moved to a header file in
+ * include/linux for final version.
+ *
+ */
+struct poch_cbuf_header {
+	__s32 group_size_bytes;
+	__s32 group_count;
+	__s32 group_offsets[0];
+};
+
+struct poch_counters {
+	__u32 fifo_empty;
+	__u32 fifo_overflow;
+	__u32 pll_unlock;
+};
+
+#define POCH_IOC_NUM			'9'
+
+#define POCH_IOC_TRANSFER_START		_IO(POCH_IOC_NUM, 0)
+#define POCH_IOC_TRANSFER_STOP		_IO(POCH_IOC_NUM, 1)
+#define POCH_IOC_GET_COUNTERS		_IOR(POCH_IOC_NUM, 2, \
+					     struct poch_counters)
+#define POCH_IOC_SYNC_GROUP_FOR_USER	_IO(POCH_IOC_NUM, 3)
+#define POCH_IOC_SYNC_GROUP_FOR_DEVICE	_IO(POCH_IOC_NUM, 4)
-- 
1.6.0.2

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