1 files changed, 512 insertions, 0 deletions

diff --git a/drivers/media/usb/pvrusb2/pvrusb2-ioread.c b/drivers/media/usb/pvrusb2/pvrusb2-ioread.c
new file mode 100644
index 000000000000..bba6115c9ae8
--- /dev/null
+++ b/drivers/media/usb/pvrusb2/pvrusb2-ioread.c
@@ -0,0 +1,512 @@
+/*
+ *
+ *
+ *  Copyright (C) 2005 Mike Isely <isely@pobox.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include "pvrusb2-ioread.h"
+#include "pvrusb2-debug.h"
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <asm/uaccess.h>
+
+#define BUFFER_COUNT 32
+#define BUFFER_SIZE PAGE_ALIGN(0x4000)
+
+struct pvr2_ioread {
+	struct pvr2_stream *stream;
+	char *buffer_storage[BUFFER_COUNT];
+	char *sync_key_ptr;
+	unsigned int sync_key_len;
+	unsigned int sync_buf_offs;
+	unsigned int sync_state;
+	unsigned int sync_trashed_count;
+	int enabled;         // Streaming is on
+	int spigot_open;     // OK to pass data to client
+	int stream_running;  // Passing data to client now
+
+	/* State relevant to current buffer being read */
+	struct pvr2_buffer *c_buf;
+	char *c_data_ptr;
+	unsigned int c_data_len;
+	unsigned int c_data_offs;
+	struct mutex mutex;
+};
+
+static int pvr2_ioread_init(struct pvr2_ioread *cp)
+{
+	unsigned int idx;
+
+	cp->stream = NULL;
+	mutex_init(&cp->mutex);
+
+	for (idx = 0; idx < BUFFER_COUNT; idx++) {
+		cp->buffer_storage[idx] = kmalloc(BUFFER_SIZE,GFP_KERNEL);
+		if (!(cp->buffer_storage[idx])) break;
+	}
+
+	if (idx < BUFFER_COUNT) {
+		// An allocation appears to have failed
+		for (idx = 0; idx < BUFFER_COUNT; idx++) {
+			if (!(cp->buffer_storage[idx])) continue;
+			kfree(cp->buffer_storage[idx]);
+		}
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void pvr2_ioread_done(struct pvr2_ioread *cp)
+{
+	unsigned int idx;
+
+	pvr2_ioread_setup(cp,NULL);
+	for (idx = 0; idx < BUFFER_COUNT; idx++) {
+		if (!(cp->buffer_storage[idx])) continue;
+		kfree(cp->buffer_storage[idx]);
+	}
+}
+
+struct pvr2_ioread *pvr2_ioread_create(void)
+{
+	struct pvr2_ioread *cp;
+	cp = kzalloc(sizeof(*cp),GFP_KERNEL);
+	if (!cp) return NULL;
+	pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_create id=%p",cp);
+	if (pvr2_ioread_init(cp) < 0) {
+		kfree(cp);
+		return NULL;
+	}
+	return cp;
+}
+
+void pvr2_ioread_destroy(struct pvr2_ioread *cp)
+{
+	if (!cp) return;
+	pvr2_ioread_done(cp);
+	pvr2_trace(PVR2_TRACE_STRUCT,"pvr2_ioread_destroy id=%p",cp);
+	if (cp->sync_key_ptr) {
+		kfree(cp->sync_key_ptr);
+		cp->sync_key_ptr = NULL;
+	}
+	kfree(cp);
+}
+
+void pvr2_ioread_set_sync_key(struct pvr2_ioread *cp,
+			      const char *sync_key_ptr,
+			      unsigned int sync_key_len)
+{
+	if (!cp) return;
+
+	if (!sync_key_ptr) sync_key_len = 0;
+	if ((sync_key_len == cp->sync_key_len) &&
+	    ((!sync_key_len) ||
+	     (!memcmp(sync_key_ptr,cp->sync_key_ptr,sync_key_len)))) return;
+
+	if (sync_key_len != cp->sync_key_len) {
+		if (cp->sync_key_ptr) {
+			kfree(cp->sync_key_ptr);
+			cp->sync_key_ptr = NULL;
+		}
+		cp->sync_key_len = 0;
+		if (sync_key_len) {
+			cp->sync_key_ptr = kmalloc(sync_key_len,GFP_KERNEL);
+			if (cp->sync_key_ptr) {
+				cp->sync_key_len = sync_key_len;
+			}
+		}
+	}
+	if (!cp->sync_key_len) return;
+	memcpy(cp->sync_key_ptr,sync_key_ptr,cp->sync_key_len);
+}
+
+static void pvr2_ioread_stop(struct pvr2_ioread *cp)
+{
+	if (!(cp->enabled)) return;
+	pvr2_trace(PVR2_TRACE_START_STOP,
+		   "/*---TRACE_READ---*/ pvr2_ioread_stop id=%p",cp);
+	pvr2_stream_kill(cp->stream);
+	cp->c_buf = NULL;
+	cp->c_data_ptr = NULL;
+	cp->c_data_len = 0;
+	cp->c_data_offs = 0;
+	cp->enabled = 0;
+	cp->stream_running = 0;
+	cp->spigot_open = 0;
+	if (cp->sync_state) {
+		pvr2_trace(PVR2_TRACE_DATA_FLOW,
+			   "/*---TRACE_READ---*/ sync_state <== 0");
+		cp->sync_state = 0;
+	}
+}
+
+static int pvr2_ioread_start(struct pvr2_ioread *cp)
+{
+	int stat;
+	struct pvr2_buffer *bp;
+	if (cp->enabled) return 0;
+	if (!(cp->stream)) return 0;
+	pvr2_trace(PVR2_TRACE_START_STOP,
+		   "/*---TRACE_READ---*/ pvr2_ioread_start id=%p",cp);
+	while ((bp = pvr2_stream_get_idle_buffer(cp->stream)) != NULL) {
+		stat = pvr2_buffer_queue(bp);
+		if (stat < 0) {
+			pvr2_trace(PVR2_TRACE_DATA_FLOW,
+				   "/*---TRACE_READ---*/"
+				   " pvr2_ioread_start id=%p"
+				   " error=%d",
+				   cp,stat);
+			pvr2_ioread_stop(cp);
+			return stat;
+		}
+	}
+	cp->enabled = !0;
+	cp->c_buf = NULL;
+	cp->c_data_ptr = NULL;
+	cp->c_data_len = 0;
+	cp->c_data_offs = 0;
+	cp->stream_running = 0;
+	if (cp->sync_key_len) {
+		pvr2_trace(PVR2_TRACE_DATA_FLOW,
+			   "/*---TRACE_READ---*/ sync_state <== 1");
+		cp->sync_state = 1;
+		cp->sync_trashed_count = 0;
+		cp->sync_buf_offs = 0;
+	}
+	cp->spigot_open = 0;
+	return 0;
+}
+
+struct pvr2_stream *pvr2_ioread_get_stream(struct pvr2_ioread *cp)
+{
+	return cp->stream;
+}
+
+int pvr2_ioread_setup(struct pvr2_ioread *cp,struct pvr2_stream *sp)
+{
+	int ret;
+	unsigned int idx;
+	struct pvr2_buffer *bp;
+
+	mutex_lock(&cp->mutex); do {
+		if (cp->stream) {
+			pvr2_trace(PVR2_TRACE_START_STOP,
+				   "/*---TRACE_READ---*/"
+				   " pvr2_ioread_setup (tear-down) id=%p",cp);
+			pvr2_ioread_stop(cp);
+			pvr2_stream_kill(cp->stream);
+			if (pvr2_stream_get_buffer_count(cp->stream)) {
+				pvr2_stream_set_buffer_count(cp->stream,0);
+			}
+			cp->stream = NULL;
+		}
+		if (sp) {
+			pvr2_trace(PVR2_TRACE_START_STOP,
+				   "/*---TRACE_READ---*/"
+				   " pvr2_ioread_setup (setup) id=%p",cp);
+			pvr2_stream_kill(sp);
+			ret = pvr2_stream_set_buffer_count(sp,BUFFER_COUNT);
+			if (ret < 0) {
+				mutex_unlock(&cp->mutex);
+				return ret;
+			}
+			for (idx = 0; idx < BUFFER_COUNT; idx++) {
+				bp = pvr2_stream_get_buffer(sp,idx);
+				pvr2_buffer_set_buffer(bp,
+						       cp->buffer_storage[idx],
+						       BUFFER_SIZE);
+			}
+			cp->stream = sp;
+		}
+	} while (0); mutex_unlock(&cp->mutex);
+
+	return 0;
+}
+
+int pvr2_ioread_set_enabled(struct pvr2_ioread *cp,int fl)
+{
+	int ret = 0;
+	if ((!fl) == (!(cp->enabled))) return ret;
+
+	mutex_lock(&cp->mutex); do {
+		if (fl) {
+			ret = pvr2_ioread_start(cp);
+		} else {
+			pvr2_ioread_stop(cp);
+		}
+	} while (0); mutex_unlock(&cp->mutex);
+	return ret;
+}
+
+static int pvr2_ioread_get_buffer(struct pvr2_ioread *cp)
+{
+	int stat;
+
+	while (cp->c_data_len <= cp->c_data_offs) {
+		if (cp->c_buf) {
+			// Flush out current buffer first.
+			stat = pvr2_buffer_queue(cp->c_buf);
+			if (stat < 0) {
+				// Streaming error...
+				pvr2_trace(PVR2_TRACE_DATA_FLOW,
+					   "/*---TRACE_READ---*/"
+					   " pvr2_ioread_read id=%p"
+					   " queue_error=%d",
+					   cp,stat);
+				pvr2_ioread_stop(cp);
+				return 0;
+			}
+			cp->c_buf = NULL;
+			cp->c_data_ptr = NULL;
+			cp->c_data_len = 0;
+			cp->c_data_offs = 0;
+		}
+		// Now get a freshly filled buffer.
+		cp->c_buf = pvr2_stream_get_ready_buffer(cp->stream);
+		if (!cp->c_buf) break; // Nothing ready; done.
+		cp->c_data_len = pvr2_buffer_get_count(cp->c_buf);
+		if (!cp->c_data_len) {
+			// Nothing transferred.  Was there an error?
+			stat = pvr2_buffer_get_status(cp->c_buf);
+			if (stat < 0) {
+				// Streaming error...
+				pvr2_trace(PVR2_TRACE_DATA_FLOW,
+					   "/*---TRACE_READ---*/"
+					   " pvr2_ioread_read id=%p"
+					   " buffer_error=%d",
+					   cp,stat);
+				pvr2_ioread_stop(cp);
+				// Give up.
+				return 0;
+			}
+			// Start over...
+			continue;
+		}
+		cp->c_data_offs = 0;
+		cp->c_data_ptr = cp->buffer_storage[
+			pvr2_buffer_get_id(cp->c_buf)];
+	}
+	return !0;
+}
+
+static void pvr2_ioread_filter(struct pvr2_ioread *cp)
+{
+	unsigned int idx;
+	if (!cp->enabled) return;
+	if (cp->sync_state != 1) return;
+
+	// Search the stream for our synchronization key.  This is made
+	// complicated by the fact that in order to be honest with
+	// ourselves here we must search across buffer boundaries...
+	mutex_lock(&cp->mutex); while (1) {
+		// Ensure we have a buffer
+		if (!pvr2_ioread_get_buffer(cp)) break;
+		if (!cp->c_data_len) break;
+
+		// Now walk the buffer contents until we match the key or
+		// run out of buffer data.
+		for (idx = cp->c_data_offs; idx < cp->c_data_len; idx++) {
+			if (cp->sync_buf_offs >= cp->sync_key_len) break;
+			if (cp->c_data_ptr[idx] ==
+			    cp->sync_key_ptr[cp->sync_buf_offs]) {
+				// Found the next key byte
+				(cp->sync_buf_offs)++;
+			} else {
+				// Whoops, mismatched.  Start key over...
+				cp->sync_buf_offs = 0;
+			}
+		}
+
+		// Consume what we've walked through
+		cp->c_data_offs += idx;
+		cp->sync_trashed_count += idx;
+
+		// If we've found the key, then update state and get out.
+		if (cp->sync_buf_offs >= cp->sync_key_len) {
+			cp->sync_trashed_count -= cp->sync_key_len;
+			pvr2_trace(PVR2_TRACE_DATA_FLOW,
+				   "/*---TRACE_READ---*/"
+				   " sync_state <== 2 (skipped %u bytes)",
+				   cp->sync_trashed_count);
+			cp->sync_state = 2;
+			cp->sync_buf_offs = 0;
+			break;
+		}
+
+		if (cp->c_data_offs < cp->c_data_len) {
+			// Sanity check - should NEVER get here
+			pvr2_trace(PVR2_TRACE_ERROR_LEGS,
+				   "ERROR: pvr2_ioread filter sync problem"
+				   " len=%u offs=%u",
+				   cp->c_data_len,cp->c_data_offs);
+			// Get out so we don't get stuck in an infinite
+			// loop.
+			break;
+		}
+
+		continue; // (for clarity)
+	} mutex_unlock(&cp->mutex);
+}
+
+int pvr2_ioread_avail(struct pvr2_ioread *cp)
+{
+	int ret;
+	if (!(cp->enabled)) {
+		// Stream is not enabled; so this is an I/O error
+		return -EIO;
+	}
+
+	if (cp->sync_state == 1) {
+		pvr2_ioread_filter(cp);
+		if (cp->sync_state == 1) return -EAGAIN;
+	}
+
+	ret = 0;
+	if (cp->stream_running) {
+		if (!pvr2_stream_get_ready_count(cp->stream)) {
+			// No data available at all right now.
+			ret = -EAGAIN;
+		}
+	} else {
+		if (pvr2_stream_get_ready_count(cp->stream) < BUFFER_COUNT/2) {
+			// Haven't buffered up enough yet; try again later
+			ret = -EAGAIN;
+		}
+	}
+
+	if ((!(cp->spigot_open)) != (!(ret == 0))) {
+		cp->spigot_open = (ret == 0);
+		pvr2_trace(PVR2_TRACE_DATA_FLOW,
+			   "/*---TRACE_READ---*/ data is %s",
+			   cp->spigot_open ? "available" : "pending");
+	}
+
+	return ret;
+}
+
+int pvr2_ioread_read(struct pvr2_ioread *cp,void __user *buf,unsigned int cnt)
+{
+	unsigned int copied_cnt;
+	unsigned int bcnt;
+	const char *src;
+	int stat;
+	int ret = 0;
+	unsigned int req_cnt = cnt;
+
+	if (!cnt) {
+		pvr2_trace(PVR2_TRACE_TRAP,
+			   "/*---TRACE_READ---*/ pvr2_ioread_read id=%p"
+			   " ZERO Request? Returning zero.",cp);
+		return 0;
+	}
+
+	stat = pvr2_ioread_avail(cp);
+	if (stat < 0) return stat;
+
+	cp->stream_running = !0;
+
+	mutex_lock(&cp->mutex); do {
+
+		// Suck data out of the buffers and copy to the user
+		copied_cnt = 0;
+		if (!buf) cnt = 0;
+		while (1) {
+			if (!pvr2_ioread_get_buffer(cp)) {
+				ret = -EIO;
+				break;
+			}
+
+			if (!cnt) break;
+
+			if (cp->sync_state == 2) {
+				// We're repeating the sync key data into
+				// the stream.
+				src = cp->sync_key_ptr + cp->sync_buf_offs;
+				bcnt = cp->sync_key_len - cp->sync_buf_offs;
+			} else {
+				// Normal buffer copy
+				src = cp->c_data_ptr + cp->c_data_offs;
+				bcnt = cp->c_data_len - cp->c_data_offs;
+			}
+
+			if (!bcnt) break;
+
+			// Don't run past user's buffer
+			if (bcnt > cnt) bcnt = cnt;
+
+			if (copy_to_user(buf,src,bcnt)) {
+				// User supplied a bad pointer?
+				// Give up - this *will* cause data
+				// to be lost.
+				ret = -EFAULT;
+				break;
+			}
+			cnt -= bcnt;
+			buf += bcnt;
+			copied_cnt += bcnt;
+
+			if (cp->sync_state == 2) {
+				// Update offset inside sync key that we're
+				// repeating back out.
+				cp->sync_buf_offs += bcnt;
+				if (cp->sync_buf_offs >= cp->sync_key_len) {
+					// Consumed entire key; switch mode
+					// to normal.
+					pvr2_trace(PVR2_TRACE_DATA_FLOW,
+						   "/*---TRACE_READ---*/"
+						   " sync_state <== 0");
+					cp->sync_state = 0;
+				}
+			} else {
+				// Update buffer offset.
+				cp->c_data_offs += bcnt;
+			}
+		}
+
+	} while (0); mutex_unlock(&cp->mutex);
+
+	if (!ret) {
+		if (copied_cnt) {
+			// If anything was copied, return that count
+			ret = copied_cnt;
+		} else {
+			// Nothing copied; suggest to caller that another
+			// attempt should be tried again later
+			ret = -EAGAIN;
+		}
+	}
+
+	pvr2_trace(PVR2_TRACE_DATA_FLOW,
+		   "/*---TRACE_READ---*/ pvr2_ioread_read"
+		   " id=%p request=%d result=%d",
+		   cp,req_cnt,ret);
+	return ret;
+}
+
+
+/*
+  Stuff for Emacs to see, in order to encourage consistent editing style:
+  *** Local Variables: ***
+  *** mode: c ***
+  *** fill-column: 75 ***
+  *** tab-width: 8 ***
+  *** c-basic-offset: 8 ***
+  *** End: ***
+  */