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path: root/drivers/media/usb/pvrusb2/pvrusb2-ioread.c
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Diffstat (limited to 'drivers/media/usb/pvrusb2/pvrusb2-ioread.c')
-rw-r--r--drivers/media/usb/pvrusb2/pvrusb2-ioread.c485
1 files changed, 485 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 000000000..46f801384
--- /dev/null
+++ b/drivers/media/usb/pvrusb2/pvrusb2-ioread.c
@@ -0,0 +1,485 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2005 Mike Isely <isely@pobox.com>
+ */
+
+#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 <linux/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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-06 08:45:09 +0000