Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / sound / firewire / lib.c

diff --git a/kernel/sound/firewire/lib.c b/kernel/sound/firewire/lib.c
new file mode 100644 (file)
index 0000000..7409edb
--- /dev/null
+++ b/kernel/sound/firewire/lib.c
@@ -0,0 +1,71 @@
+/*
+ * miscellaneous helper functions
+ *
+ * Copyright (c) Clemens Ladisch <clemens@ladisch.de>
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/module.h>
+#include "lib.h"
+
+#define ERROR_RETRY_DELAY_MS   20
+
+/**
+ * snd_fw_transaction - send a request and wait for its completion
+ * @unit: the driver's unit on the target device
+ * @tcode: the transaction code
+ * @offset: the address in the target's address space
+ * @buffer: input/output data
+ * @length: length of @buffer
+ * @flags: use %FW_FIXED_GENERATION and add the generation value to attempt the
+ *         request only in that generation; use %FW_QUIET to suppress error
+ *         messages
+ *
+ * Submits an asynchronous request to the target device, and waits for the
+ * response.  The node ID and the current generation are derived from @unit.
+ * On a bus reset or an error, the transaction is retried a few times.
+ * Returns zero on success, or a negative error code.
+ */
+int snd_fw_transaction(struct fw_unit *unit, int tcode,
+                      u64 offset, void *buffer, size_t length,
+                      unsigned int flags)
+{
+       struct fw_device *device = fw_parent_device(unit);
+       int generation, rcode, tries = 0;
+
+       generation = flags & FW_GENERATION_MASK;
+       for (;;) {
+               if (!(flags & FW_FIXED_GENERATION)) {
+                       generation = device->generation;
+                       smp_rmb(); /* node_id vs. generation */
+               }
+               rcode = fw_run_transaction(device->card, tcode,
+                                          device->node_id, generation,
+                                          device->max_speed, offset,
+                                          buffer, length);
+
+               if (rcode == RCODE_COMPLETE)
+                       return 0;
+
+               if (rcode == RCODE_GENERATION && (flags & FW_FIXED_GENERATION))
+                       return -EAGAIN;
+
+               if (rcode_is_permanent_error(rcode) || ++tries >= 3) {
+                       if (!(flags & FW_QUIET))
+                               dev_err(&unit->device,
+                                       "transaction failed: %s\n",
+                                       fw_rcode_string(rcode));
+                       return -EIO;
+               }
+
+               msleep(ERROR_RETRY_DELAY_MS);
+       }
+}
+EXPORT_SYMBOL(snd_fw_transaction);
+
+MODULE_DESCRIPTION("FireWire audio helper functions");
+MODULE_AUTHOR("Clemens Ladisch <clemens@ladisch.de>");
+MODULE_LICENSE("GPL v2");