Changeset 6fd365d in mainline for uspace/lib/c/generic/device/hw_res.c

Timestamp:

2012-08-18T14:20:28Z (13 years ago)

Author:

Jan Vesely <jano.vesely@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

1864948

Parents:

bc6762f

Message:

libc,libdrv: Add remaining bytes query to DMA(hw_res) interface.

File:

• uspace/lib/c/generic/device/hw_res.c (modified) (1 diff)

uspace/lib/c/generic/device/hw_res.c

@@ -115 +115 @@
 }
 
+/**
+ * Query remaining bytes in the buffer.
+ * @param channel DMA Channel 1,2,3 for 8 bit transfers, 5,6,7 for 16 bit.
+ * @return Number of bytes remaining in the buffer(>=0) or error code(<0).
+ */
+int hw_res_dma_channel_remain(async_sess_t *sess, unsigned channel)
+{
+        async_exch_t *exch = async_exchange_begin(sess);
+        if (exch == NULL)
+                return ENOMEM;
+        sysarg_t remain;
+        const int ret = async_req_2_1(exch, DEV_IFACE_ID(HW_RES_DEV_IFACE),
+            HW_RES_DMA_CHANNEL_REMAIN, channel, &remain);
+        async_exchange_end(exch);
+        if (ret == EOK)
+                return remain;
+        return ret;
+}
+
 /** @}
  */