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path: root/drivers/char/xillybus/xillybus_core.c
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-rw-r--r--drivers/char/xillybus/xillybus_core.c2103
1 files changed, 2103 insertions, 0 deletions
diff --git a/drivers/char/xillybus/xillybus_core.c b/drivers/char/xillybus/xillybus_core.c
new file mode 100644
index 000000000000..b827fa095f1b
--- /dev/null
+++ b/drivers/char/xillybus/xillybus_core.c
@@ -0,0 +1,2103 @@
+/*
+ * linux/drivers/misc/xillybus_core.c
+ *
+ * Copyright 2011 Xillybus Ltd, http://xillybus.com
+ *
+ * Driver for the Xillybus FPGA/host framework.
+ *
+ * This driver interfaces with a special IP core in an FPGA, setting up
+ * a pipe between a hardware FIFO in the programmable logic and a device
+ * file in the host. The number of such pipes and their attributes are
+ * set up on the logic. This driver detects these automatically and
+ * creates the device files accordingly.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the smems of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/list.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/crc32.h>
+#include <linux/poll.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include "xillybus.h"
+
+MODULE_DESCRIPTION("Xillybus core functions");
+MODULE_AUTHOR("Eli Billauer, Xillybus Ltd.");
+MODULE_VERSION("1.07");
+MODULE_ALIAS("xillybus_core");
+MODULE_LICENSE("GPL v2");
+
+/* General timeout is 100 ms, rx timeout is 10 ms */
+#define XILLY_RX_TIMEOUT (10*HZ/1000)
+#define XILLY_TIMEOUT (100*HZ/1000)
+
+#define fpga_msg_ctrl_reg 0x0008
+#define fpga_dma_control_reg 0x0020
+#define fpga_dma_bufno_reg 0x0024
+#define fpga_dma_bufaddr_lowaddr_reg 0x0028
+#define fpga_dma_bufaddr_highaddr_reg 0x002c
+#define fpga_buf_ctrl_reg 0x0030
+#define fpga_buf_offset_reg 0x0034
+#define fpga_endian_reg 0x0040
+
+#define XILLYMSG_OPCODE_RELEASEBUF 1
+#define XILLYMSG_OPCODE_QUIESCEACK 2
+#define XILLYMSG_OPCODE_FIFOEOF 3
+#define XILLYMSG_OPCODE_FATAL_ERROR 4
+#define XILLYMSG_OPCODE_NONEMPTY 5
+
+static const char xillyname[] = "xillybus";
+
+static struct class *xillybus_class;
+
+/*
+ * ep_list_lock is the last lock to be taken; No other lock requests are
+ * allowed while holding it. It merely protects list_of_endpoints, and not
+ * the endpoints listed in it.
+ */
+
+static LIST_HEAD(list_of_endpoints);
+static struct mutex ep_list_lock;
+static struct workqueue_struct *xillybus_wq;
+
+/*
+ * Locking scheme: Mutexes protect invocations of character device methods.
+ * If both locks are taken, wr_mutex is taken first, rd_mutex second.
+ *
+ * wr_spinlock protects wr_*_buf_idx, wr_empty, wr_sleepy, wr_ready and the
+ * buffers' end_offset fields against changes made by IRQ handler (and in
+ * theory, other file request handlers, but the mutex handles that). Nothing
+ * else.
+ * They are held for short direct memory manipulations. Needless to say,
+ * no mutex locking is allowed when a spinlock is held.
+ *
+ * rd_spinlock does the same with rd_*_buf_idx, rd_empty and end_offset.
+ *
+ * register_mutex is endpoint-specific, and is held when non-atomic
+ * register operations are performed. wr_mutex and rd_mutex may be
+ * held when register_mutex is taken, but none of the spinlocks. Note that
+ * register_mutex doesn't protect against sporadic buf_ctrl_reg writes
+ * which are unrelated to buf_offset_reg, since they are harmless.
+ *
+ * Blocking on the wait queues is allowed with mutexes held, but not with
+ * spinlocks.
+ *
+ * Only interruptible blocking is allowed on mutexes and wait queues.
+ *
+ * All in all, the locking order goes (with skips allowed, of course):
+ * wr_mutex -> rd_mutex -> register_mutex -> wr_spinlock -> rd_spinlock
+ */
+
+static void malformed_message(struct xilly_endpoint *endpoint, u32 *buf)
+{
+ int opcode;
+ int msg_channel, msg_bufno, msg_data, msg_dir;
+
+ opcode = (buf[0] >> 24) & 0xff;
+ msg_dir = buf[0] & 1;
+ msg_channel = (buf[0] >> 1) & 0x7ff;
+ msg_bufno = (buf[0] >> 12) & 0x3ff;
+ msg_data = buf[1] & 0xfffffff;
+
+ dev_warn(endpoint->dev,
+ "Malformed message (skipping): opcode=%d, channel=%03x, dir=%d, bufno=%03x, data=%07x\n",
+ opcode, msg_channel, msg_dir, msg_bufno, msg_data);
+}
+
+/*
+ * xillybus_isr assumes the interrupt is allocated exclusively to it,
+ * which is the natural case MSI and several other hardware-oriented
+ * interrupts. Sharing is not allowed.
+ */
+
+irqreturn_t xillybus_isr(int irq, void *data)
+{
+ struct xilly_endpoint *ep = data;
+ u32 *buf;
+ unsigned int buf_size;
+ int i;
+ int opcode;
+ unsigned int msg_channel, msg_bufno, msg_data, msg_dir;
+ struct xilly_channel *channel;
+
+ buf = ep->msgbuf_addr;
+ buf_size = ep->msg_buf_size/sizeof(u32);
+
+ ep->ephw->hw_sync_sgl_for_cpu(ep,
+ ep->msgbuf_dma_addr,
+ ep->msg_buf_size,
+ DMA_FROM_DEVICE);
+
+ for (i = 0; i < buf_size; i += 2) {
+ if (((buf[i+1] >> 28) & 0xf) != ep->msg_counter) {
+ malformed_message(ep, &buf[i]);
+ dev_warn(ep->dev,
+ "Sending a NACK on counter %x (instead of %x) on entry %d\n",
+ ((buf[i+1] >> 28) & 0xf),
+ ep->msg_counter,
+ i/2);
+
+ if (++ep->failed_messages > 10) {
+ dev_err(ep->dev,
+ "Lost sync with interrupt messages. Stopping.\n");
+ } else {
+ ep->ephw->hw_sync_sgl_for_device(
+ ep,
+ ep->msgbuf_dma_addr,
+ ep->msg_buf_size,
+ DMA_FROM_DEVICE);
+
+ iowrite32(0x01, /* Message NACK */
+ ep->registers + fpga_msg_ctrl_reg);
+ }
+ return IRQ_HANDLED;
+ } else if (buf[i] & (1 << 22)) /* Last message */
+ break;
+ }
+
+ if (i >= buf_size) {
+ dev_err(ep->dev, "Bad interrupt message. Stopping.\n");
+ return IRQ_HANDLED;
+ }
+
+ buf_size = i + 2;
+
+ for (i = 0; i < buf_size; i += 2) { /* Scan through messages */
+ opcode = (buf[i] >> 24) & 0xff;
+
+ msg_dir = buf[i] & 1;
+ msg_channel = (buf[i] >> 1) & 0x7ff;
+ msg_bufno = (buf[i] >> 12) & 0x3ff;
+ msg_data = buf[i+1] & 0xfffffff;
+
+ switch (opcode) {
+ case XILLYMSG_OPCODE_RELEASEBUF:
+ if ((msg_channel > ep->num_channels) ||
+ (msg_channel == 0)) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+
+ channel = ep->channels[msg_channel];
+
+ if (msg_dir) { /* Write channel */
+ if (msg_bufno >= channel->num_wr_buffers) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+ spin_lock(&channel->wr_spinlock);
+ channel->wr_buffers[msg_bufno]->end_offset =
+ msg_data;
+ channel->wr_fpga_buf_idx = msg_bufno;
+ channel->wr_empty = 0;
+ channel->wr_sleepy = 0;
+ spin_unlock(&channel->wr_spinlock);
+
+ wake_up_interruptible(&channel->wr_wait);
+
+ } else {
+ /* Read channel */
+
+ if (msg_bufno >= channel->num_rd_buffers) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+
+ spin_lock(&channel->rd_spinlock);
+ channel->rd_fpga_buf_idx = msg_bufno;
+ channel->rd_full = 0;
+ spin_unlock(&channel->rd_spinlock);
+
+ wake_up_interruptible(&channel->rd_wait);
+ if (!channel->rd_synchronous)
+ queue_delayed_work(
+ xillybus_wq,
+ &channel->rd_workitem,
+ XILLY_RX_TIMEOUT);
+ }
+
+ break;
+ case XILLYMSG_OPCODE_NONEMPTY:
+ if ((msg_channel > ep->num_channels) ||
+ (msg_channel == 0) || (!msg_dir) ||
+ !ep->channels[msg_channel]->wr_supports_nonempty) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+
+ channel = ep->channels[msg_channel];
+
+ if (msg_bufno >= channel->num_wr_buffers) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+ spin_lock(&channel->wr_spinlock);
+ if (msg_bufno == channel->wr_host_buf_idx)
+ channel->wr_ready = 1;
+ spin_unlock(&channel->wr_spinlock);
+
+ wake_up_interruptible(&channel->wr_ready_wait);
+
+ break;
+ case XILLYMSG_OPCODE_QUIESCEACK:
+ ep->idtlen = msg_data;
+ wake_up_interruptible(&ep->ep_wait);
+
+ break;
+ case XILLYMSG_OPCODE_FIFOEOF:
+ if ((msg_channel > ep->num_channels) ||
+ (msg_channel == 0) || (!msg_dir) ||
+ !ep->channels[msg_channel]->num_wr_buffers) {
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+ channel = ep->channels[msg_channel];
+ spin_lock(&channel->wr_spinlock);
+ channel->wr_eof = msg_bufno;
+ channel->wr_sleepy = 0;
+
+ channel->wr_hangup = channel->wr_empty &&
+ (channel->wr_host_buf_idx == msg_bufno);
+
+ spin_unlock(&channel->wr_spinlock);
+
+ wake_up_interruptible(&channel->wr_wait);
+
+ break;
+ case XILLYMSG_OPCODE_FATAL_ERROR:
+ ep->fatal_error = 1;
+ wake_up_interruptible(&ep->ep_wait); /* For select() */
+ dev_err(ep->dev,
+ "FPGA reported a fatal error. This means that the low-level communication with the device has failed. This hardware problem is most likely unrelated to Xillybus (neither kernel module nor FPGA core), but reports are still welcome. All I/O is aborted.\n");
+ break;
+ default:
+ malformed_message(ep, &buf[i]);
+ break;
+ }
+ }
+
+ ep->ephw->hw_sync_sgl_for_device(ep,
+ ep->msgbuf_dma_addr,
+ ep->msg_buf_size,
+ DMA_FROM_DEVICE);
+
+ ep->msg_counter = (ep->msg_counter + 1) & 0xf;
+ ep->failed_messages = 0;
+ iowrite32(0x03, ep->registers + fpga_msg_ctrl_reg); /* Message ACK */
+
+ return IRQ_HANDLED;
+}
+EXPORT_SYMBOL(xillybus_isr);
+
+/*
+ * A few trivial memory management functions.
+ * NOTE: These functions are used only on probe and remove, and therefore
+ * no locks are applied!
+ */
+
+static void xillybus_autoflush(struct work_struct *work);
+
+struct xilly_alloc_state {
+ void *salami;
+ int left_of_salami;
+ int nbuffer;
+ enum dma_data_direction direction;
+ u32 regdirection;
+};
+
+static int xilly_get_dma_buffers(struct xilly_endpoint *ep,
+ struct xilly_alloc_state *s,
+ struct xilly_buffer **buffers,
+ int bufnum, int bytebufsize)
+{
+ int i, rc;
+ dma_addr_t dma_addr;
+ struct device *dev = ep->dev;
+ struct xilly_buffer *this_buffer = NULL; /* Init to silence warning */
+
+ if (buffers) { /* Not the message buffer */
+ this_buffer = devm_kcalloc(dev, bufnum,
+ sizeof(struct xilly_buffer),
+ GFP_KERNEL);
+ if (!this_buffer)
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < bufnum; i++) {
+ /*
+ * Buffers are expected in descending size order, so there
+ * is either enough space for this buffer or none at all.
+ */
+
+ if ((s->left_of_salami < bytebufsize) &&
+ (s->left_of_salami > 0)) {
+ dev_err(ep->dev,
+ "Corrupt buffer allocation in IDT. Aborting.\n");
+ return -ENODEV;
+ }
+
+ if (s->left_of_salami == 0) {
+ int allocorder, allocsize;
+
+ allocsize = PAGE_SIZE;
+ allocorder = 0;
+ while (bytebufsize > allocsize) {
+ allocsize *= 2;
+ allocorder++;
+ }
+
+ s->salami = (void *) devm_get_free_pages(
+ dev,
+ GFP_KERNEL | __GFP_DMA32 | __GFP_ZERO,
+ allocorder);
+ if (!s->salami)
+ return -ENOMEM;
+
+ s->left_of_salami = allocsize;
+ }
+
+ rc = ep->ephw->map_single(ep, s->salami,
+ bytebufsize, s->direction,
+ &dma_addr);
+ if (rc)
+ return rc;
+
+ iowrite32((u32) (dma_addr & 0xffffffff),
+ ep->registers + fpga_dma_bufaddr_lowaddr_reg);
+ iowrite32(((u32) ((((u64) dma_addr) >> 32) & 0xffffffff)),
+ ep->registers + fpga_dma_bufaddr_highaddr_reg);
+
+ if (buffers) { /* Not the message buffer */
+ this_buffer->addr = s->salami;
+ this_buffer->dma_addr = dma_addr;
+ buffers[i] = this_buffer++;
+
+ iowrite32(s->regdirection | s->nbuffer++,
+ ep->registers + fpga_dma_bufno_reg);
+ } else {
+ ep->msgbuf_addr = s->salami;
+ ep->msgbuf_dma_addr = dma_addr;
+ ep->msg_buf_size = bytebufsize;
+
+ iowrite32(s->regdirection,
+ ep->registers + fpga_dma_bufno_reg);
+ }
+
+ s->left_of_salami -= bytebufsize;
+ s->salami += bytebufsize;
+ }
+ return 0;
+}
+
+static int xilly_setupchannels(struct xilly_endpoint *ep,
+ unsigned char *chandesc,
+ int entries)
+{
+ struct device *dev = ep->dev;
+ int i, entry, rc;
+ struct xilly_channel *channel;
+ int channelnum, bufnum, bufsize, format, is_writebuf;
+ int bytebufsize;
+ int synchronous, allowpartial, exclusive_open, seekable;
+ int supports_nonempty;
+ int msg_buf_done = 0;
+
+ struct xilly_alloc_state rd_alloc = {
+ .salami = NULL,
+ .left_of_salami = 0,
+ .nbuffer = 1,
+ .direction = DMA_TO_DEVICE,
+ .regdirection = 0,
+ };
+
+ struct xilly_alloc_state wr_alloc = {
+ .salami = NULL,
+ .left_of_salami = 0,
+ .nbuffer = 1,
+ .direction = DMA_FROM_DEVICE,
+ .regdirection = 0x80000000,
+ };
+
+ channel = devm_kcalloc(dev, ep->num_channels,
+ sizeof(struct xilly_channel), GFP_KERNEL);
+ if (!channel)
+ return -ENOMEM;
+
+ ep->channels = devm_kcalloc(dev, ep->num_channels + 1,
+ sizeof(struct xilly_channel *),
+ GFP_KERNEL);
+ if (!ep->channels)
+ return -ENOMEM;
+
+ ep->channels[0] = NULL; /* Channel 0 is message buf. */
+
+ /* Initialize all channels with defaults */
+
+ for (i = 1; i <= ep->num_channels; i++) {
+ channel->wr_buffers = NULL;
+ channel->rd_buffers = NULL;
+ channel->num_wr_buffers = 0;
+ channel->num_rd_buffers = 0;
+ channel->wr_fpga_buf_idx = -1;
+ channel->wr_host_buf_idx = 0;
+ channel->wr_host_buf_pos = 0;
+ channel->wr_empty = 1;
+ channel->wr_ready = 0;
+ channel->wr_sleepy = 1;
+ channel->rd_fpga_buf_idx = 0;
+ channel->rd_host_buf_idx = 0;
+ channel->rd_host_buf_pos = 0;
+ channel->rd_full = 0;
+ channel->wr_ref_count = 0;
+ channel->rd_ref_count = 0;
+
+ spin_lock_init(&channel->wr_spinlock);
+ spin_lock_init(&channel->rd_spinlock);
+ mutex_init(&channel->wr_mutex);
+ mutex_init(&channel->rd_mutex);
+ init_waitqueue_head(&channel->rd_wait);
+ init_waitqueue_head(&channel->wr_wait);
+ init_waitqueue_head(&channel->wr_ready_wait);
+
+ INIT_DELAYED_WORK(&channel->rd_workitem, xillybus_autoflush);
+
+ channel->endpoint = ep;
+ channel->chan_num = i;
+
+ channel->log2_element_size = 0;
+
+ ep->channels[i] = channel++;
+ }
+
+ for (entry = 0; entry < entries; entry++, chandesc += 4) {
+ struct xilly_buffer **buffers = NULL;
+
+ is_writebuf = chandesc[0] & 0x01;
+ channelnum = (chandesc[0] >> 1) | ((chandesc[1] & 0x0f) << 7);
+ format = (chandesc[1] >> 4) & 0x03;
+ allowpartial = (chandesc[1] >> 6) & 0x01;
+ synchronous = (chandesc[1] >> 7) & 0x01;
+ bufsize = 1 << (chandesc[2] & 0x1f);
+ bufnum = 1 << (chandesc[3] & 0x0f);
+ exclusive_open = (chandesc[2] >> 7) & 0x01;
+ seekable = (chandesc[2] >> 6) & 0x01;
+ supports_nonempty = (chandesc[2] >> 5) & 0x01;
+
+ if ((channelnum > ep->num_channels) ||
+ ((channelnum == 0) && !is_writebuf)) {
+ dev_err(ep->dev,
+ "IDT requests channel out of range. Aborting.\n");
+ return -ENODEV;
+ }
+
+ channel = ep->channels[channelnum]; /* NULL for msg channel */
+
+ if (!is_writebuf || channelnum > 0) {
+ channel->log2_element_size = ((format > 2) ?
+ 2 : format);
+
+ bytebufsize = channel->rd_buf_size = bufsize *
+ (1 << channel->log2_element_size);
+
+ buffers = devm_kcalloc(dev, bufnum,
+ sizeof(struct xilly_buffer *),
+ GFP_KERNEL);
+ if (!buffers)
+ return -ENOMEM;
+ } else {
+ bytebufsize = bufsize << 2;
+ }
+
+ if (!is_writebuf) {
+ channel->num_rd_buffers = bufnum;
+ channel->rd_allow_partial = allowpartial;
+ channel->rd_synchronous = synchronous;
+ channel->rd_exclusive_open = exclusive_open;
+ channel->seekable = seekable;
+
+ channel->rd_buffers = buffers;
+ rc = xilly_get_dma_buffers(ep, &rd_alloc, buffers,
+ bufnum, bytebufsize);
+ } else if (channelnum > 0) {
+ channel->num_wr_buffers = bufnum;
+
+ channel->seekable = seekable;
+ channel->wr_supports_nonempty = supports_nonempty;
+
+ channel->wr_allow_partial = allowpartial;
+ channel->wr_synchronous = synchronous;
+ channel->wr_exclusive_open = exclusive_open;
+
+ channel->wr_buffers = buffers;
+ rc = xilly_get_dma_buffers(ep, &wr_alloc, buffers,
+ bufnum, bytebufsize);
+ } else {
+ rc = xilly_get_dma_buffers(ep, &wr_alloc, NULL,
+ bufnum, bytebufsize);
+ msg_buf_done++;
+ }
+
+ if (rc)
+ return -ENOMEM;
+ }
+
+ if (!msg_buf_done) {
+ dev_err(ep->dev,
+ "Corrupt IDT: No message buffer. Aborting.\n");
+ return -ENODEV;
+ }
+ return 0;
+}
+
+static int xilly_scan_idt(struct xilly_endpoint *endpoint,
+ struct xilly_idt_handle *idt_handle)
+{
+ int count = 0;
+ unsigned char *idt = endpoint->channels[1]->wr_buffers[0]->addr;
+ unsigned char *end_of_idt = idt + endpoint->idtlen - 4;
+ unsigned char *scan;
+ int len;
+
+ scan = idt;
+ idt_handle->idt = idt;
+
+ scan++; /* Skip version number */
+
+ while ((scan <= end_of_idt) && *scan) {
+ while ((scan <= end_of_idt) && *scan++)
+ /* Do nothing, just scan thru string */;
+ count++;
+ }
+
+ scan++;
+
+ if (scan > end_of_idt) {
+ dev_err(endpoint->dev,
+ "IDT device name list overflow. Aborting.\n");
+ return -ENODEV;
+ }
+ idt_handle->chandesc = scan;
+
+ len = endpoint->idtlen - (3 + ((int) (scan - idt)));
+
+ if (len & 0x03) {
+ dev_err(endpoint->dev,
+ "Corrupt IDT device name list. Aborting.\n");
+ return -ENODEV;
+ }
+
+ idt_handle->entries = len >> 2;
+ endpoint->num_channels = count;
+
+ return 0;
+}
+
+static int xilly_obtain_idt(struct xilly_endpoint *endpoint)
+{
+ struct xilly_channel *channel;
+ unsigned char *version;
+ long t;
+
+ channel = endpoint->channels[1]; /* This should be generated ad-hoc */
+
+ channel->wr_sleepy = 1;
+
+ iowrite32(1 |
+ (3 << 24), /* Opcode 3 for channel 0 = Send IDT */
+ endpoint->registers + fpga_buf_ctrl_reg);
+
+ t = wait_event_interruptible_timeout(channel->wr_wait,
+ (!channel->wr_sleepy),
+ XILLY_TIMEOUT);
+
+ if (t <= 0) {
+ dev_err(endpoint->dev, "Failed to obtain IDT. Aborting.\n");
+
+ if (endpoint->fatal_error)
+ return -EIO;
+
+ return -ENODEV;
+ }
+
+ endpoint->ephw->hw_sync_sgl_for_cpu(
+ channel->endpoint,
+ channel->wr_buffers[0]->dma_addr,
+ channel->wr_buf_size,
+ DMA_FROM_DEVICE);
+
+ if (channel->wr_buffers[0]->end_offset != endpoint->idtlen) {
+ dev_err(endpoint->dev,
+ "IDT length mismatch (%d != %d). Aborting.\n",
+ channel->wr_buffers[0]->end_offset, endpoint->idtlen);
+ return -ENODEV;
+ }
+
+ if (crc32_le(~0, channel->wr_buffers[0]->addr,
+ endpoint->idtlen+1) != 0) {
+ dev_err(endpoint->dev, "IDT failed CRC check. Aborting.\n");
+ return -ENODEV;
+ }
+
+ version = channel->wr_buffers[0]->addr;
+
+ /* Check version number. Accept anything below 0x82 for now. */
+ if (*version > 0x82) {
+ dev_err(endpoint->dev,
+ "No support for IDT version 0x%02x. Maybe the xillybus driver needs an upgarde. Aborting.\n",
+ *version);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static ssize_t xillybus_read(struct file *filp, char __user *userbuf,
+ size_t count, loff_t *f_pos)
+{
+ ssize_t rc;
+ unsigned long flags;
+ int bytes_done = 0;
+ int no_time_left = 0;
+ long deadline, left_to_sleep;
+ struct xilly_channel *channel = filp->private_data;
+
+ int empty, reached_eof, exhausted, ready;
+ /* Initializations are there only to silence warnings */
+
+ int howmany = 0, bufpos = 0, bufidx = 0, bufferdone = 0;
+ int waiting_bufidx;
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ deadline = jiffies + 1 + XILLY_RX_TIMEOUT;
+
+ rc = mutex_lock_interruptible(&channel->wr_mutex);
+ if (rc)
+ return rc;
+
+ while (1) { /* Note that we may drop mutex within this loop */
+ int bytes_to_do = count - bytes_done;
+
+ spin_lock_irqsave(&channel->wr_spinlock, flags);
+
+ empty = channel->wr_empty;
+ ready = !empty || channel->wr_ready;
+
+ if (!empty) {
+ bufidx = channel->wr_host_buf_idx;
+ bufpos = channel->wr_host_buf_pos;
+ howmany = ((channel->wr_buffers[bufidx]->end_offset
+ + 1) << channel->log2_element_size)
+ - bufpos;
+
+ /* Update wr_host_* to its post-operation state */
+ if (howmany > bytes_to_do) {
+ bufferdone = 0;
+
+ howmany = bytes_to_do;
+ channel->wr_host_buf_pos += howmany;
+ } else {
+ bufferdone = 1;
+
+ channel->wr_host_buf_pos = 0;
+
+ if (bufidx == channel->wr_fpga_buf_idx) {
+ channel->wr_empty = 1;
+ channel->wr_sleepy = 1;
+ channel->wr_ready = 0;
+ }
+
+ if (bufidx >= (channel->num_wr_buffers - 1))
+ channel->wr_host_buf_idx = 0;
+ else
+ channel->wr_host_buf_idx++;
+ }
+ }
+
+ /*
+ * Marking our situation after the possible changes above,
+ * for use after releasing the spinlock.
+ *
+ * empty = empty before change
+ * exhasted = empty after possible change
+ */
+
+ reached_eof = channel->wr_empty &&
+ (channel->wr_host_buf_idx == channel->wr_eof);
+ channel->wr_hangup = reached_eof;
+ exhausted = channel->wr_empty;
+ waiting_bufidx = channel->wr_host_buf_idx;
+
+ spin_unlock_irqrestore(&channel->wr_spinlock, flags);
+
+ if (!empty) { /* Go on, now without the spinlock */
+
+ if (bufpos == 0) /* Position zero means it's virgin */
+ channel->endpoint->ephw->hw_sync_sgl_for_cpu(
+ channel->endpoint,
+ channel->wr_buffers[bufidx]->dma_addr,
+ channel->wr_buf_size,
+ DMA_FROM_DEVICE);
+
+ if (copy_to_user(
+ userbuf,
+ channel->wr_buffers[bufidx]->addr
+ + bufpos, howmany))
+ rc = -EFAULT;
+
+ userbuf += howmany;
+ bytes_done += howmany;
+
+ if (bufferdone) {
+ channel->endpoint->ephw->hw_sync_sgl_for_device(
+ channel->endpoint,
+ channel->wr_buffers[bufidx]->dma_addr,
+ channel->wr_buf_size,
+ DMA_FROM_DEVICE);
+
+ /*
+ * Tell FPGA the buffer is done with. It's an
+ * atomic operation to the FPGA, so what
+ * happens with other channels doesn't matter,
+ * and the certain channel is protected with
+ * the channel-specific mutex.
+ */
+
+ iowrite32(1 | (channel->chan_num << 1) |
+ (bufidx << 12),
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+ }
+
+ if (rc) {
+ mutex_unlock(&channel->wr_mutex);
+ return rc;
+ }
+ }
+
+ /* This includes a zero-count return = EOF */
+ if ((bytes_done >= count) || reached_eof)
+ break;
+
+ if (!exhausted)
+ continue; /* More in RAM buffer(s)? Just go on. */
+
+ if ((bytes_done > 0) &&
+ (no_time_left ||
+ (channel->wr_synchronous && channel->wr_allow_partial)))
+ break;
+
+ /*
+ * Nonblocking read: The "ready" flag tells us that the FPGA
+ * has data to send. In non-blocking mode, if it isn't on,
+ * just return. But if there is, we jump directly to the point
+ * where we ask for the FPGA to send all it has, and wait
+ * until that data arrives. So in a sense, we *do* block in
+ * nonblocking mode, but only for a very short time.
+ */
+
+ if (!no_time_left && (filp->f_flags & O_NONBLOCK)) {
+ if (bytes_done > 0)
+ break;
+
+ if (ready)
+ goto desperate;
+
+ rc = -EAGAIN;
+ break;
+ }
+
+ if (!no_time_left || (bytes_done > 0)) {
+ /*
+ * Note that in case of an element-misaligned read
+ * request, offsetlimit will include the last element,
+ * which will be partially read from.
+ */
+ int offsetlimit = ((count - bytes_done) - 1) >>
+ channel->log2_element_size;
+ int buf_elements = channel->wr_buf_size >>
+ channel->log2_element_size;
+
+ /*
+ * In synchronous mode, always send an offset limit.
+ * Just don't send a value too big.
+ */
+
+ if (channel->wr_synchronous) {
+ /* Don't request more than one buffer */
+ if (channel->wr_allow_partial &&
+ (offsetlimit >= buf_elements))
+ offsetlimit = buf_elements - 1;
+
+ /* Don't request more than all buffers */
+ if (!channel->wr_allow_partial &&
+ (offsetlimit >=
+ (buf_elements * channel->num_wr_buffers)))
+ offsetlimit = buf_elements *
+ channel->num_wr_buffers - 1;
+ }
+
+ /*
+ * In asynchronous mode, force early flush of a buffer
+ * only if that will allow returning a full count. The
+ * "offsetlimit < ( ... )" rather than "<=" excludes
+ * requesting a full buffer, which would obviously
+ * cause a buffer transmission anyhow
+ */
+
+ if (channel->wr_synchronous ||
+ (offsetlimit < (buf_elements - 1))) {
+ mutex_lock(&channel->endpoint->register_mutex);
+
+ iowrite32(offsetlimit,
+ channel->endpoint->registers +
+ fpga_buf_offset_reg);
+
+ iowrite32(1 | (channel->chan_num << 1) |
+ (2 << 24) | /* 2 = offset limit */
+ (waiting_bufidx << 12),
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+
+ mutex_unlock(&channel->endpoint->
+ register_mutex);
+ }
+ }
+
+ /*
+ * If partial completion is disallowed, there is no point in
+ * timeout sleeping. Neither if no_time_left is set and
+ * there's no data.
+ */
+
+ if (!channel->wr_allow_partial ||
+ (no_time_left && (bytes_done == 0))) {
+ /*
+ * This do-loop will run more than once if another
+ * thread reasserted wr_sleepy before we got the mutex
+ * back, so we try again.
+ */
+
+ do {
+ mutex_unlock(&channel->wr_mutex);
+
+ if (wait_event_interruptible(
+ channel->wr_wait,
+ (!channel->wr_sleepy)))
+ goto interrupted;
+
+ if (mutex_lock_interruptible(
+ &channel->wr_mutex))
+ goto interrupted;
+ } while (channel->wr_sleepy);
+
+ continue;
+
+interrupted: /* Mutex is not held if got here */
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+ if (bytes_done)
+ return bytes_done;
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN; /* Don't admit snoozing */
+ return -EINTR;
+ }
+
+ left_to_sleep = deadline - ((long) jiffies);
+
+ /*
+ * If our time is out, skip the waiting. We may miss wr_sleepy
+ * being deasserted but hey, almost missing the train is like
+ * missing it.
+ */
+
+ if (left_to_sleep > 0) {
+ left_to_sleep =
+ wait_event_interruptible_timeout(
+ channel->wr_wait,
+ (!channel->wr_sleepy),
+ left_to_sleep);
+
+ if (left_to_sleep > 0) /* wr_sleepy deasserted */
+ continue;
+
+ if (left_to_sleep < 0) { /* Interrupt */
+ mutex_unlock(&channel->wr_mutex);
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+ if (bytes_done)
+ return bytes_done;
+ return -EINTR;
+ }
+ }
+
+desperate:
+ no_time_left = 1; /* We're out of sleeping time. Desperate! */
+
+ if (bytes_done == 0) {
+ /*
+ * Reaching here means that we allow partial return,
+ * that we've run out of time, and that we have
+ * nothing to return.
+ * So tell the FPGA to send anything it has or gets.
+ */
+
+ iowrite32(1 | (channel->chan_num << 1) |
+ (3 << 24) | /* Opcode 3, flush it all! */
+ (waiting_bufidx << 12),
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+ }
+
+ /*
+ * Reaching here means that we *do* have data in the buffer,
+ * but the "partial" flag disallows returning less than
+ * required. And we don't have as much. So loop again,
+ * which is likely to end up blocking indefinitely until
+ * enough data has arrived.
+ */
+ }
+
+ mutex_unlock(&channel->wr_mutex);
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ if (rc)
+ return rc;
+
+ return bytes_done;
+}
+
+/*
+ * The timeout argument takes values as follows:
+ * >0 : Flush with timeout
+ * ==0 : Flush, and wait idefinitely for the flush to complete
+ * <0 : Autoflush: Flush only if there's a single buffer occupied
+ */
+
+static int xillybus_myflush(struct xilly_channel *channel, long timeout)
+{
+ int rc;
+ unsigned long flags;
+
+ int end_offset_plus1;
+ int bufidx, bufidx_minus1;
+ int i;
+ int empty;
+ int new_rd_host_buf_pos;
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+ rc = mutex_lock_interruptible(&channel->rd_mutex);
+ if (rc)
+ return rc;
+
+ /*
+ * Don't flush a closed channel. This can happen when the work queued
+ * autoflush thread fires off after the file has closed. This is not
+ * an error, just something to dismiss.
+ */
+
+ if (!channel->rd_ref_count)
+ goto done;
+
+ bufidx = channel->rd_host_buf_idx;
+
+ bufidx_minus1 = (bufidx == 0) ?
+ channel->num_rd_buffers - 1 :
+ bufidx - 1;
+
+ end_offset_plus1 = channel->rd_host_buf_pos >>
+ channel->log2_element_size;
+
+ new_rd_host_buf_pos = channel->rd_host_buf_pos -
+ (end_offset_plus1 << channel->log2_element_size);
+
+ /* Submit the current buffer if it's nonempty */
+ if (end_offset_plus1) {
+ unsigned char *tail = channel->rd_buffers[bufidx]->addr +
+ (end_offset_plus1 << channel->log2_element_size);
+
+ /* Copy unflushed data, so we can put it in next buffer */
+ for (i = 0; i < new_rd_host_buf_pos; i++)
+ channel->rd_leftovers[i] = *tail++;
+
+ spin_lock_irqsave(&channel->rd_spinlock, flags);
+
+ /* Autoflush only if a single buffer is occupied */
+
+ if ((timeout < 0) &&
+ (channel->rd_full ||
+ (bufidx_minus1 != channel->rd_fpga_buf_idx))) {
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+ /*
+ * A new work item may be queued by the ISR exactly
+ * now, since the execution of a work item allows the
+ * queuing of a new one while it's running.
+ */
+ goto done;
+ }
+
+ /* The 4th element is never needed for data, so it's a flag */
+ channel->rd_leftovers[3] = (new_rd_host_buf_pos != 0);
+
+ /* Set up rd_full to reflect a certain moment's state */
+
+ if (bufidx == channel->rd_fpga_buf_idx)
+ channel->rd_full = 1;
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+
+ if (bufidx >= (channel->num_rd_buffers - 1))
+ channel->rd_host_buf_idx = 0;
+ else
+ channel->rd_host_buf_idx++;
+
+ channel->endpoint->ephw->hw_sync_sgl_for_device(
+ channel->endpoint,
+ channel->rd_buffers[bufidx]->dma_addr,
+ channel->rd_buf_size,
+ DMA_TO_DEVICE);
+
+ mutex_lock(&channel->endpoint->register_mutex);
+
+ iowrite32(end_offset_plus1 - 1,
+ channel->endpoint->registers + fpga_buf_offset_reg);
+
+ iowrite32((channel->chan_num << 1) | /* Channel ID */
+ (2 << 24) | /* Opcode 2, submit buffer */
+ (bufidx << 12),
+ channel->endpoint->registers + fpga_buf_ctrl_reg);
+
+ mutex_unlock(&channel->endpoint->register_mutex);
+ } else if (bufidx == 0) {
+ bufidx = channel->num_rd_buffers - 1;
+ } else {
+ bufidx--;
+ }
+
+ channel->rd_host_buf_pos = new_rd_host_buf_pos;
+
+ if (timeout < 0)
+ goto done; /* Autoflush */
+
+ /*
+ * bufidx is now the last buffer written to (or equal to
+ * rd_fpga_buf_idx if buffer was never written to), and
+ * channel->rd_host_buf_idx the one after it.
+ *
+ * If bufidx == channel->rd_fpga_buf_idx we're either empty or full.
+ */
+
+ while (1) { /* Loop waiting for draining of buffers */
+ spin_lock_irqsave(&channel->rd_spinlock, flags);
+
+ if (bufidx != channel->rd_fpga_buf_idx)
+ channel->rd_full = 1; /*
+ * Not really full,
+ * but needs waiting.
+ */
+
+ empty = !channel->rd_full;
+
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+
+ if (empty)
+ break;
+
+ /*
+ * Indefinite sleep with mutex taken. With data waiting for
+ * flushing user should not be surprised if open() for write
+ * sleeps.
+ */
+ if (timeout == 0)
+ wait_event_interruptible(channel->rd_wait,
+ (!channel->rd_full));
+
+ else if (wait_event_interruptible_timeout(
+ channel->rd_wait,
+ (!channel->rd_full),
+ timeout) == 0) {
+ dev_warn(channel->endpoint->dev,
+ "Timed out while flushing. Output data may be lost.\n");
+
+ rc = -ETIMEDOUT;
+ break;
+ }
+
+ if (channel->rd_full) {
+ rc = -EINTR;
+ break;
+ }
+ }
+
+done:
+ mutex_unlock(&channel->rd_mutex);
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ return rc;
+}
+
+static int xillybus_flush(struct file *filp, fl_owner_t id)
+{
+ if (!(filp->f_mode & FMODE_WRITE))
+ return 0;
+
+ return xillybus_myflush(filp->private_data, HZ); /* 1 second timeout */
+}
+
+static void xillybus_autoflush(struct work_struct *work)
+{
+ struct delayed_work *workitem = container_of(
+ work, struct delayed_work, work);
+ struct xilly_channel *channel = container_of(
+ workitem, struct xilly_channel, rd_workitem);
+ int rc;
+
+ rc = xillybus_myflush(channel, -1);
+ if (rc == -EINTR)
+ dev_warn(channel->endpoint->dev,
+ "Autoflush failed because work queue thread got a signal.\n");
+ else if (rc)
+ dev_err(channel->endpoint->dev,
+ "Autoflush failed under weird circumstances.\n");
+}
+
+static ssize_t xillybus_write(struct file *filp, const char __user *userbuf,
+ size_t count, loff_t *f_pos)
+{
+ ssize_t rc;
+ unsigned long flags;
+ int bytes_done = 0;
+ struct xilly_channel *channel = filp->private_data;
+
+ int full, exhausted;
+ /* Initializations are there only to silence warnings */
+
+ int howmany = 0, bufpos = 0, bufidx = 0, bufferdone = 0;
+ int end_offset_plus1 = 0;
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ rc = mutex_lock_interruptible(&channel->rd_mutex);
+ if (rc)
+ return rc;
+
+ while (1) {
+ int bytes_to_do = count - bytes_done;
+
+ spin_lock_irqsave(&channel->rd_spinlock, flags);
+
+ full = channel->rd_full;
+
+ if (!full) {
+ bufidx = channel->rd_host_buf_idx;
+ bufpos = channel->rd_host_buf_pos;
+ howmany = channel->rd_buf_size - bufpos;
+
+ /*
+ * Update rd_host_* to its state after this operation.
+ * count=0 means committing the buffer immediately,
+ * which is like flushing, but not necessarily block.
+ */
+
+ if ((howmany > bytes_to_do) &&
+ (count ||
+ ((bufpos >> channel->log2_element_size) == 0))) {
+ bufferdone = 0;
+
+ howmany = bytes_to_do;
+ channel->rd_host_buf_pos += howmany;
+ } else {
+ bufferdone = 1;
+
+ if (count) {
+ end_offset_plus1 =
+ channel->rd_buf_size >>
+ channel->log2_element_size;
+ channel->rd_host_buf_pos = 0;
+ } else {
+ unsigned char *tail;
+ int i;
+
+ end_offset_plus1 = bufpos >>
+ channel->log2_element_size;
+
+ channel->rd_host_buf_pos -=
+ end_offset_plus1 <<
+ channel->log2_element_size;
+
+ tail = channel->
+ rd_buffers[bufidx]->addr +
+ (end_offset_plus1 <<
+ channel->log2_element_size);
+
+ for (i = 0;
+ i < channel->rd_host_buf_pos;
+ i++)
+ channel->rd_leftovers[i] =
+ *tail++;
+ }
+
+ if (bufidx == channel->rd_fpga_buf_idx)
+ channel->rd_full = 1;
+
+ if (bufidx >= (channel->num_rd_buffers - 1))
+ channel->rd_host_buf_idx = 0;
+ else
+ channel->rd_host_buf_idx++;
+ }
+ }
+
+ /*
+ * Marking our situation after the possible changes above,
+ * for use after releasing the spinlock.
+ *
+ * full = full before change
+ * exhasted = full after possible change
+ */
+
+ exhausted = channel->rd_full;
+
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+
+ if (!full) { /* Go on, now without the spinlock */
+ unsigned char *head =
+ channel->rd_buffers[bufidx]->addr;
+ int i;
+
+ if ((bufpos == 0) || /* Zero means it's virgin */
+ (channel->rd_leftovers[3] != 0)) {
+ channel->endpoint->ephw->hw_sync_sgl_for_cpu(
+ channel->endpoint,
+ channel->rd_buffers[bufidx]->dma_addr,
+ channel->rd_buf_size,
+ DMA_TO_DEVICE);
+
+ /* Virgin, but leftovers are due */
+ for (i = 0; i < bufpos; i++)
+ *head++ = channel->rd_leftovers[i];
+
+ channel->rd_leftovers[3] = 0; /* Clear flag */
+ }
+
+ if (copy_from_user(
+ channel->rd_buffers[bufidx]->addr + bufpos,
+ userbuf, howmany))
+ rc = -EFAULT;
+
+ userbuf += howmany;
+ bytes_done += howmany;
+
+ if (bufferdone) {
+ channel->endpoint->ephw->hw_sync_sgl_for_device(
+ channel->endpoint,
+ channel->rd_buffers[bufidx]->dma_addr,
+ channel->rd_buf_size,
+ DMA_TO_DEVICE);
+
+ mutex_lock(&channel->endpoint->register_mutex);
+
+ iowrite32(end_offset_plus1 - 1,
+ channel->endpoint->registers +
+ fpga_buf_offset_reg);
+
+ iowrite32((channel->chan_num << 1) |
+ (2 << 24) | /* 2 = submit buffer */
+ (bufidx << 12),
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+
+ mutex_unlock(&channel->endpoint->
+ register_mutex);
+
+ channel->rd_leftovers[3] =
+ (channel->rd_host_buf_pos != 0);
+ }
+
+ if (rc) {
+ mutex_unlock(&channel->rd_mutex);
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ if (!channel->rd_synchronous)
+ queue_delayed_work(
+ xillybus_wq,
+ &channel->rd_workitem,
+ XILLY_RX_TIMEOUT);
+
+ return rc;
+ }
+ }
+
+ if (bytes_done >= count)
+ break;
+
+ if (!exhausted)
+ continue; /* If there's more space, just go on */
+
+ if ((bytes_done > 0) && channel->rd_allow_partial)
+ break;
+
+ /*
+ * Indefinite sleep with mutex taken. With data waiting for
+ * flushing, user should not be surprised if open() for write
+ * sleeps.
+ */
+
+ if (filp->f_flags & O_NONBLOCK) {
+ rc = -EAGAIN;
+ break;
+ }
+
+ if (wait_event_interruptible(channel->rd_wait,
+ (!channel->rd_full))) {
+ mutex_unlock(&channel->rd_mutex);
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ if (bytes_done)
+ return bytes_done;
+ return -EINTR;
+ }
+ }
+
+ mutex_unlock(&channel->rd_mutex);
+
+ if (!channel->rd_synchronous)
+ queue_delayed_work(xillybus_wq,
+ &channel->rd_workitem,
+ XILLY_RX_TIMEOUT);
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ if (rc)
+ return rc;
+
+ if ((channel->rd_synchronous) && (bytes_done > 0)) {
+ rc = xillybus_myflush(filp->private_data, 0); /* No timeout */
+
+ if (rc && (rc != -EINTR))
+ return rc;
+ }
+
+ return bytes_done;
+}
+
+static int xillybus_open(struct inode *inode, struct file *filp)
+{
+ int rc = 0;
+ unsigned long flags;
+ int minor = iminor(inode);
+ int major = imajor(inode);
+ struct xilly_endpoint *ep_iter, *endpoint = NULL;
+ struct xilly_channel *channel;
+
+ mutex_lock(&ep_list_lock);
+
+ list_for_each_entry(ep_iter, &list_of_endpoints, ep_list) {
+ if ((ep_iter->major == major) &&
+ (minor >= ep_iter->lowest_minor) &&
+ (minor < (ep_iter->lowest_minor +
+ ep_iter->num_channels))) {
+ endpoint = ep_iter;
+ break;
+ }
+ }
+ mutex_unlock(&ep_list_lock);
+
+ if (!endpoint) {
+ pr_err("xillybus: open() failed to find a device for major=%d and minor=%d\n",
+ major, minor);
+ return -ENODEV;
+ }
+
+ if (endpoint->fatal_error)
+ return -EIO;
+
+ channel = endpoint->channels[1 + minor - endpoint->lowest_minor];
+ filp->private_data = channel;
+
+ /*
+ * It gets complicated because:
+ * 1. We don't want to take a mutex we don't have to
+ * 2. We don't want to open one direction if the other will fail.
+ */
+
+ if ((filp->f_mode & FMODE_READ) && (!channel->num_wr_buffers))
+ return -ENODEV;
+
+ if ((filp->f_mode & FMODE_WRITE) && (!channel->num_rd_buffers))
+ return -ENODEV;
+
+ if ((filp->f_mode & FMODE_READ) && (filp->f_flags & O_NONBLOCK) &&
+ (channel->wr_synchronous || !channel->wr_allow_partial ||
+ !channel->wr_supports_nonempty)) {
+ dev_err(endpoint->dev,
+ "open() failed: O_NONBLOCK not allowed for read on this device\n");
+ return -ENODEV;
+ }
+
+ if ((filp->f_mode & FMODE_WRITE) && (filp->f_flags & O_NONBLOCK) &&
+ (channel->rd_synchronous || !channel->rd_allow_partial)) {
+ dev_err(endpoint->dev,
+ "open() failed: O_NONBLOCK not allowed for write on this device\n");
+ return -ENODEV;
+ }
+
+ /*
+ * Note: open() may block on getting mutexes despite O_NONBLOCK.
+ * This shouldn't occur normally, since multiple open of the same
+ * file descriptor is almost always prohibited anyhow
+ * (*_exclusive_open is normally set in real-life systems).
+ */
+
+ if (filp->f_mode & FMODE_READ) {
+ rc = mutex_lock_interruptible(&channel->wr_mutex);
+ if (rc)
+ return rc;
+ }
+
+ if (filp->f_mode & FMODE_WRITE) {
+ rc = mutex_lock_interruptible(&channel->rd_mutex);
+ if (rc)
+ goto unlock_wr;
+ }
+
+ if ((filp->f_mode & FMODE_READ) &&
+ (channel->wr_ref_count != 0) &&
+ (channel->wr_exclusive_open)) {
+ rc = -EBUSY;
+ goto unlock;
+ }
+
+ if ((filp->f_mode & FMODE_WRITE) &&
+ (channel->rd_ref_count != 0) &&
+ (channel->rd_exclusive_open)) {
+ rc = -EBUSY;
+ goto unlock;
+ }
+
+ if (filp->f_mode & FMODE_READ) {
+ if (channel->wr_ref_count == 0) { /* First open of file */
+ /* Move the host to first buffer */
+ spin_lock_irqsave(&channel->wr_spinlock, flags);
+ channel->wr_host_buf_idx = 0;
+ channel->wr_host_buf_pos = 0;
+ channel->wr_fpga_buf_idx = -1;
+ channel->wr_empty = 1;
+ channel->wr_ready = 0;
+ channel->wr_sleepy = 1;
+ channel->wr_eof = -1;
+ channel->wr_hangup = 0;
+
+ spin_unlock_irqrestore(&channel->wr_spinlock, flags);
+
+ iowrite32(1 | (channel->chan_num << 1) |
+ (4 << 24) | /* Opcode 4, open channel */
+ ((channel->wr_synchronous & 1) << 23),
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+ }
+
+ channel->wr_ref_count++;
+ }
+
+ if (filp->f_mode & FMODE_WRITE) {
+ if (channel->rd_ref_count == 0) { /* First open of file */
+ /* Move the host to first buffer */
+ spin_lock_irqsave(&channel->rd_spinlock, flags);
+ channel->rd_host_buf_idx = 0;
+ channel->rd_host_buf_pos = 0;
+ channel->rd_leftovers[3] = 0; /* No leftovers. */
+ channel->rd_fpga_buf_idx = channel->num_rd_buffers - 1;
+ channel->rd_full = 0;
+
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+
+ iowrite32((channel->chan_num << 1) |
+ (4 << 24), /* Opcode 4, open channel */
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+ }
+
+ channel->rd_ref_count++;
+ }
+
+unlock:
+ if (filp->f_mode & FMODE_WRITE)
+ mutex_unlock(&channel->rd_mutex);
+unlock_wr:
+ if (filp->f_mode & FMODE_READ)
+ mutex_unlock(&channel->wr_mutex);
+
+ if (!rc && (!channel->seekable))
+ return nonseekable_open(inode, filp);
+
+ return rc;
+}
+
+static int xillybus_release(struct inode *inode, struct file *filp)
+{
+ unsigned long flags;
+ struct xilly_channel *channel = filp->private_data;
+
+ int buf_idx;
+ int eof;
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ if (filp->f_mode & FMODE_WRITE) {
+ mutex_lock(&channel->rd_mutex);
+
+ channel->rd_ref_count--;
+
+ if (channel->rd_ref_count == 0) {
+ /*
+ * We rely on the kernel calling flush()
+ * before we get here.
+ */
+
+ iowrite32((channel->chan_num << 1) | /* Channel ID */
+ (5 << 24), /* Opcode 5, close channel */
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+ }
+ mutex_unlock(&channel->rd_mutex);
+ }
+
+ if (filp->f_mode & FMODE_READ) {
+ mutex_lock(&channel->wr_mutex);
+
+ channel->wr_ref_count--;
+
+ if (channel->wr_ref_count == 0) {
+ iowrite32(1 | (channel->chan_num << 1) |
+ (5 << 24), /* Opcode 5, close channel */
+ channel->endpoint->registers +
+ fpga_buf_ctrl_reg);
+
+ /*
+ * This is crazily cautious: We make sure that not
+ * only that we got an EOF (be it because we closed
+ * the channel or because of a user's EOF), but verify
+ * that it's one beyond the last buffer arrived, so
+ * we have no leftover buffers pending before wrapping
+ * up (which can only happen in asynchronous channels,
+ * BTW)
+ */
+
+ while (1) {
+ spin_lock_irqsave(&channel->wr_spinlock,
+ flags);
+ buf_idx = channel->wr_fpga_buf_idx;
+ eof = channel->wr_eof;
+ channel->wr_sleepy = 1;
+ spin_unlock_irqrestore(&channel->wr_spinlock,
+ flags);
+
+ /*
+ * Check if eof points at the buffer after
+ * the last one the FPGA submitted. Note that
+ * no EOF is marked by negative eof.
+ */
+
+ buf_idx++;
+ if (buf_idx == channel->num_wr_buffers)
+ buf_idx = 0;
+
+ if (buf_idx == eof)
+ break;
+
+ /*
+ * Steal extra 100 ms if awaken by interrupt.
+ * This is a simple workaround for an
+ * interrupt pending when entering, which would
+ * otherwise result in declaring the hardware
+ * non-responsive.
+ */
+
+ if (wait_event_interruptible(
+ channel->wr_wait,
+ (!channel->wr_sleepy)))
+ msleep(100);
+
+ if (channel->wr_sleepy) {
+ mutex_unlock(&channel->wr_mutex);
+ dev_warn(channel->endpoint->dev,
+ "Hardware failed to respond to close command, therefore left in messy state.\n");
+ return -EINTR;
+ }
+ }
+ }
+
+ mutex_unlock(&channel->wr_mutex);
+ }
+
+ return 0;
+}
+
+static loff_t xillybus_llseek(struct file *filp, loff_t offset, int whence)
+{
+ struct xilly_channel *channel = filp->private_data;
+ loff_t pos = filp->f_pos;
+ int rc = 0;
+
+ /*
+ * Take both mutexes not allowing interrupts, since it seems like
+ * common applications don't expect an -EINTR here. Besides, multiple
+ * access to a single file descriptor on seekable devices is a mess
+ * anyhow.
+ */
+
+ if (channel->endpoint->fatal_error)
+ return -EIO;
+
+ mutex_lock(&channel->wr_mutex);
+ mutex_lock(&channel->rd_mutex);
+
+ switch (whence) {
+ case SEEK_SET:
+ pos = offset;
+ break;
+ case SEEK_CUR:
+ pos += offset;
+ break;
+ case SEEK_END:
+ pos = offset; /* Going to the end => to the beginning */
+ break;
+ default:
+ rc = -EINVAL;
+ goto end;
+ }
+
+ /* In any case, we must finish on an element boundary */
+ if (pos & ((1 << channel->log2_element_size) - 1)) {
+ rc = -EINVAL;
+ goto end;
+ }
+
+ mutex_lock(&channel->endpoint->register_mutex);
+
+ iowrite32(pos >> channel->log2_element_size,
+ channel->endpoint->registers + fpga_buf_offset_reg);
+
+ iowrite32((channel->chan_num << 1) |
+ (6 << 24), /* Opcode 6, set address */
+ channel->endpoint->registers + fpga_buf_ctrl_reg);
+
+ mutex_unlock(&channel->endpoint->register_mutex);
+
+end:
+ mutex_unlock(&channel->rd_mutex);
+ mutex_unlock(&channel->wr_mutex);
+
+ if (rc) /* Return error after releasing mutexes */
+ return rc;
+
+ filp->f_pos = pos;
+
+ /*
+ * Since seekable devices are allowed only when the channel is
+ * synchronous, we assume that there is no data pending in either
+ * direction (which holds true as long as no concurrent access on the
+ * file descriptor takes place).
+ * The only thing we may need to throw away is leftovers from partial
+ * write() flush.
+ */
+
+ channel->rd_leftovers[3] = 0;
+
+ return pos;
+}
+
+static unsigned int xillybus_poll(struct file *filp, poll_table *wait)
+{
+ struct xilly_channel *channel = filp->private_data;
+ unsigned int mask = 0;
+ unsigned long flags;
+
+ poll_wait(filp, &channel->endpoint->ep_wait, wait);
+
+ /*
+ * poll() won't play ball regarding read() channels which
+ * aren't asynchronous and support the nonempty message. Allowing
+ * that will create situations where data has been delivered at
+ * the FPGA, and users expecting select() to wake up, which it may
+ * not.
+ */
+
+ if (!channel->wr_synchronous && channel->wr_supports_nonempty) {
+ poll_wait(filp, &channel->wr_wait, wait);
+ poll_wait(filp, &channel->wr_ready_wait, wait);
+
+ spin_lock_irqsave(&channel->wr_spinlock, flags);
+ if (!channel->wr_empty || channel->wr_ready)
+ mask |= POLLIN | POLLRDNORM;
+
+ if (channel->wr_hangup)
+ /*
+ * Not POLLHUP, because its behavior is in the
+ * mist, and POLLIN does what we want: Wake up
+ * the read file descriptor so it sees EOF.
+ */
+ mask |= POLLIN | POLLRDNORM;
+ spin_unlock_irqrestore(&channel->wr_spinlock, flags);
+ }
+
+ /*
+ * If partial data write is disallowed on a write() channel,
+ * it's pointless to ever signal OK to write, because is could
+ * block despite some space being available.
+ */
+
+ if (channel->rd_allow_partial) {
+ poll_wait(filp, &channel->rd_wait, wait);
+
+ spin_lock_irqsave(&channel->rd_spinlock, flags);
+ if (!channel->rd_full)
+ mask |= POLLOUT | POLLWRNORM;
+ spin_unlock_irqrestore(&channel->rd_spinlock, flags);
+ }
+
+ if (channel->endpoint->fatal_error)
+ mask |= POLLERR;
+
+ return mask;
+}
+
+static const struct file_operations xillybus_fops = {
+ .owner = THIS_MODULE,
+ .read = xillybus_read,
+ .write = xillybus_write,
+ .open = xillybus_open,
+ .flush = xillybus_flush,
+ .release = xillybus_release,
+ .llseek = xillybus_llseek,
+ .poll = xillybus_poll,
+};
+
+static int xillybus_init_chrdev(struct xilly_endpoint *endpoint,
+ const unsigned char *idt)
+{
+ int rc;
+ dev_t dev;
+ int devnum, i, minor, major;
+ char devname[48];
+ struct device *device;
+
+ rc = alloc_chrdev_region(&dev, 0, /* minor start */
+ endpoint->num_channels,
+ xillyname);
+ if (rc) {
+ dev_warn(endpoint->dev, "Failed to obtain major/minors");
+ return rc;
+ }
+
+ endpoint->major = major = MAJOR(dev);
+ endpoint->lowest_minor = minor = MINOR(dev);
+
+ cdev_init(&endpoint->cdev, &xillybus_fops);
+ endpoint->cdev.owner = endpoint->ephw->owner;
+ rc = cdev_add(&endpoint->cdev, MKDEV(major, minor),
+ endpoint->num_channels);
+ if (rc) {
+ dev_warn(endpoint->dev, "Failed to add cdev. Aborting.\n");
+ goto unregister_chrdev;
+ }
+
+ idt++;
+
+ for (i = minor, devnum = 0;
+ devnum < endpoint->num_channels;
+ devnum++, i++) {
+ snprintf(devname, sizeof(devname)-1, "xillybus_%s", idt);
+
+ devname[sizeof(devname)-1] = 0; /* Should never matter */
+
+ while (*idt++)
+ /* Skip to next */;
+
+ device = device_create(xillybus_class,
+ NULL,
+ MKDEV(major, i),
+ NULL,
+ "%s", devname);
+
+ if (IS_ERR(device)) {
+ dev_warn(endpoint->dev,
+ "Failed to create %s device. Aborting.\n",
+ devname);
+ rc = -ENODEV;
+ goto unroll_device_create;
+ }
+ }
+
+ dev_info(endpoint->dev, "Created %d device files.\n",
+ endpoint->num_channels);
+ return 0; /* succeed */
+
+unroll_device_create:
+ devnum--; i--;
+ for (; devnum >= 0; devnum--, i--)
+ device_destroy(xillybus_class, MKDEV(major, i));
+
+ cdev_del(&endpoint->cdev);
+unregister_chrdev:
+ unregister_chrdev_region(MKDEV(major, minor), endpoint->num_channels);
+
+ return rc;
+}
+
+static void xillybus_cleanup_chrdev(struct xilly_endpoint *endpoint)
+{
+ int minor;
+
+ for (minor = endpoint->lowest_minor;
+ minor < (endpoint->lowest_minor + endpoint->num_channels);
+ minor++)
+ device_destroy(xillybus_class, MKDEV(endpoint->major, minor));
+ cdev_del(&endpoint->cdev);
+ unregister_chrdev_region(MKDEV(endpoint->major,
+ endpoint->lowest_minor),
+ endpoint->num_channels);
+
+ dev_info(endpoint->dev, "Removed %d device files.\n",
+ endpoint->num_channels);
+}
+
+struct xilly_endpoint *xillybus_init_endpoint(struct pci_dev *pdev,
+ struct device *dev,
+ struct xilly_endpoint_hardware
+ *ephw)
+{
+ struct xilly_endpoint *endpoint;
+
+ endpoint = devm_kzalloc(dev, sizeof(*endpoint), GFP_KERNEL);
+ if (!endpoint)
+ return NULL;
+
+ endpoint->pdev = pdev;
+ endpoint->dev = dev;
+ endpoint->ephw = ephw;
+ endpoint->msg_counter = 0x0b;
+ endpoint->failed_messages = 0;
+ endpoint->fatal_error = 0;
+
+ init_waitqueue_head(&endpoint->ep_wait);
+ mutex_init(&endpoint->register_mutex);
+
+ return endpoint;
+}
+EXPORT_SYMBOL(xillybus_init_endpoint);
+
+static int xilly_quiesce(struct xilly_endpoint *endpoint)
+{
+ long t;
+
+ endpoint->idtlen = -1;
+
+ iowrite32((u32) (endpoint->dma_using_dac & 0x0001),
+ endpoint->registers + fpga_dma_control_reg);
+
+ t = wait_event_interruptible_timeout(endpoint->ep_wait,
+ (endpoint->idtlen >= 0),
+ XILLY_TIMEOUT);
+ if (t <= 0) {
+ dev_err(endpoint->dev,
+ "Failed to quiesce the device on exit.\n");
+ return -ENODEV;
+ }
+ return 0;
+}
+
+int xillybus_endpoint_discovery(struct xilly_endpoint *endpoint)
+{
+ int rc;
+ long t;
+
+ void *bootstrap_resources;
+ int idtbuffersize = (1 << PAGE_SHIFT);
+ struct device *dev = endpoint->dev;
+
+ /*
+ * The bogus IDT is used during bootstrap for allocating the initial
+ * message buffer, and then the message buffer and space for the IDT
+ * itself. The initial message buffer is of a single page's size, but
+ * it's soon replaced with a more modest one (and memory is freed).
+ */
+
+ unsigned char bogus_idt[8] = { 1, 224, (PAGE_SHIFT)-2, 0,
+ 3, 192, PAGE_SHIFT, 0 };
+ struct xilly_idt_handle idt_handle;
+
+ /*
+ * Writing the value 0x00000001 to Endianness register signals which
+ * endianness this processor is using, so the FPGA can swap words as
+ * necessary.
+ */
+
+ iowrite32(1, endpoint->registers + fpga_endian_reg);
+
+ /* Bootstrap phase I: Allocate temporary message buffer */
+
+ bootstrap_resources = devres_open_group(dev, NULL, GFP_KERNEL);
+ if (!bootstrap_resources)
+ return -ENOMEM;
+
+ endpoint->num_channels = 0;
+
+ rc = xilly_setupchannels(endpoint, bogus_idt, 1);
+ if (rc)
+ return rc;
+
+ /* Clear the message subsystem (and counter in particular) */
+ iowrite32(0x04, endpoint->registers + fpga_msg_ctrl_reg);
+
+ endpoint->idtlen = -1;
+
+ /*
+ * Set DMA 32/64 bit mode, quiesce the device (?!) and get IDT
+ * buffer size.
+ */
+ iowrite32((u32) (endpoint->dma_using_dac & 0x0001),
+ endpoint->registers + fpga_dma_control_reg);
+
+ t = wait_event_interruptible_timeout(endpoint->ep_wait,
+ (endpoint->idtlen >= 0),
+ XILLY_TIMEOUT);
+ if (t <= 0) {
+ dev_err(endpoint->dev, "No response from FPGA. Aborting.\n");
+ return -ENODEV;
+ }
+
+ /* Enable DMA */
+ iowrite32((u32) (0x0002 | (endpoint->dma_using_dac & 0x0001)),
+ endpoint->registers + fpga_dma_control_reg);
+
+ /* Bootstrap phase II: Allocate buffer for IDT and obtain it */
+ while (endpoint->idtlen >= idtbuffersize) {
+ idtbuffersize *= 2;
+ bogus_idt[6]++;
+ }
+
+ endpoint->num_channels = 1;
+
+ rc = xilly_setupchannels(endpoint, bogus_idt, 2);
+ if (rc)
+ goto failed_idt;
+
+ rc = xilly_obtain_idt(endpoint);
+ if (rc)
+ goto failed_idt;
+
+ rc = xilly_scan_idt(endpoint, &idt_handle);
+ if (rc)
+ goto failed_idt;
+
+ devres_close_group(dev, bootstrap_resources);
+
+ /* Bootstrap phase III: Allocate buffers according to IDT */
+
+ rc = xilly_setupchannels(endpoint,
+ idt_handle.chandesc,
+ idt_handle.entries);
+ if (rc)
+ goto failed_idt;
+
+ /*
+ * endpoint is now completely configured. We put it on the list
+ * available to open() before registering the char device(s)
+ */
+
+ mutex_lock(&ep_list_lock);
+ list_add_tail(&endpoint->ep_list, &list_of_endpoints);
+ mutex_unlock(&ep_list_lock);
+
+ rc = xillybus_init_chrdev(endpoint, idt_handle.idt);
+ if (rc)
+ goto failed_chrdevs;
+
+ devres_release_group(dev, bootstrap_resources);
+
+ return 0;
+
+failed_chrdevs:
+ mutex_lock(&ep_list_lock);
+ list_del(&endpoint->ep_list);
+ mutex_unlock(&ep_list_lock);
+
+failed_idt:
+ xilly_quiesce(endpoint);
+ flush_workqueue(xillybus_wq);
+
+ return rc;
+}
+EXPORT_SYMBOL(xillybus_endpoint_discovery);
+
+void xillybus_endpoint_remove(struct xilly_endpoint *endpoint)
+{
+ xillybus_cleanup_chrdev(endpoint);
+
+ mutex_lock(&ep_list_lock);
+ list_del(&endpoint->ep_list);
+ mutex_unlock(&ep_list_lock);
+
+ xilly_quiesce(endpoint);
+
+ /*
+ * Flushing is done upon endpoint release to prevent access to memory
+ * just about to be released. This makes the quiesce complete.
+ */
+ flush_workqueue(xillybus_wq);
+}
+EXPORT_SYMBOL(xillybus_endpoint_remove);
+
+static int __init xillybus_init(void)
+{
+ mutex_init(&ep_list_lock);
+
+ xillybus_class = class_create(THIS_MODULE, xillyname);
+ if (IS_ERR(xillybus_class))
+ return PTR_ERR(xillybus_class);
+
+ xillybus_wq = alloc_workqueue(xillyname, 0, 0);
+ if (!xillybus_wq) {
+ class_destroy(xillybus_class);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void __exit xillybus_exit(void)
+{
+ /* flush_workqueue() was called for each endpoint released */
+ destroy_workqueue(xillybus_wq);
+
+ class_destroy(xillybus_class);
+}
+
+module_init(xillybus_init);
+module_exit(xillybus_exit);

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