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Diffstat (limited to 'digital/avr/modules/isp/isp_frame.c')
-rw-r--r--digital/avr/modules/isp/isp_frame.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/digital/avr/modules/isp/isp_frame.c b/digital/avr/modules/isp/isp_frame.c
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index 00000000..e663a58a
--- /dev/null
+++ b/digital/avr/modules/isp/isp_frame.c
@@ -0,0 +1,173 @@
+/* isp_frame.c - AVR068 serial frames support. */
+/* avr.isp - Serial programming AVR module. {{{
+ *
+ * Copyright (C) 2009 Nicolas Schodet
+ *
+ * APBTeam:
+ * Web: http://apbteam.org/
+ * Email: team AT apbteam DOT org
+ *
+ * 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, or
+ * (at your option) any later version.
+ *
+ * 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 "common.h"
+
+#include "isp_frame.h"
+
+#define ISP_FRAME_PROTO_START 27
+#define ISP_FRAME_PROTO_TOKEN 14
+#define ISP_FRAME_PROTO_ANSWER_CKSUM_ERROR 0xb0
+#define ISP_FRAME_PROTO_STATUS_CKSUM_ERROR 0xc1
+
+/** State of frame decoding. */
+enum isp_frame_state_t
+{
+ /** Start state, nothing decoded. */
+ ISP_FRAME_STATE_START,
+ /** After message started, waiting sequence number. */
+ ISP_FRAME_STATE_WAIT_SEQ,
+ /** Waiting first length byte. */
+ ISP_FRAME_STATE_WAIT_LEN_MSB,
+ /** Waiting second length byte. */
+ ISP_FRAME_STATE_WAIT_LEN_LSB,
+ /** Waiting token. */
+ ISP_FRAME_STATE_WAIT_TOKEN,
+ /** Reading data. */
+ ISP_FRAME_STATE_DATA,
+ /** Waiting checksum. */
+ ISP_FRAME_STATE_WAIT_CKSUM,
+};
+
+/** Context. */
+struct isp_frame_t
+{
+ /** Current state. */
+ uint8_t state;
+ /** Message sequence number. */
+ uint8_t seq;
+ /** Message length. */
+ uint16_t len;
+ /** Checksum current value. */
+ uint8_t cksum;
+ /** Buffer to store frame until validated. */
+ uint8_t buffer[AC_ISP_FRAME_BUFFER_SIZE];
+ /** Used buffer length. */
+ uint8_t buffer_len;
+};
+
+/** Global context. */
+static struct isp_frame_t isp_frame_global;
+
+/** Process frame in buffer. */
+static void
+isp_frame_process (void);
+
+void
+isp_frame_accept_char (uint8_t c)
+{
+ switch (isp_frame_global.state)
+ {
+ case ISP_FRAME_STATE_START:
+ if (c == ISP_FRAME_PROTO_START)
+ {
+ isp_frame_global.cksum = ISP_FRAME_PROTO_START;
+ isp_frame_global.state++;
+ }
+ break;
+ case ISP_FRAME_STATE_WAIT_SEQ:
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.seq = c;
+ isp_frame_global.state++;
+ break;
+ case ISP_FRAME_STATE_WAIT_LEN_MSB:
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.len = c << 8;
+ isp_frame_global.state++;
+ break;
+ case ISP_FRAME_STATE_WAIT_LEN_LSB:
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.len |= c;
+ isp_frame_global.buffer_len = 0;
+ if (isp_frame_global.len == 0
+ || isp_frame_global.len > AC_ISP_FRAME_BUFFER_SIZE)
+ isp_frame_global.state = ISP_FRAME_STATE_START;
+ else
+ isp_frame_global.state++;
+ break;
+ case ISP_FRAME_STATE_WAIT_TOKEN:
+ if (c == ISP_FRAME_PROTO_TOKEN)
+ {
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.state++;
+ }
+ else
+ isp_frame_global.state = ISP_FRAME_STATE_START;
+ break;
+ case ISP_FRAME_STATE_DATA:
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.buffer[isp_frame_global.buffer_len++] = c;
+ if (isp_frame_global.buffer_len == isp_frame_global.len)
+ isp_frame_global.state++;
+ break;
+ case ISP_FRAME_STATE_WAIT_CKSUM:
+ isp_frame_global.cksum ^= c;
+ isp_frame_global.state = ISP_FRAME_STATE_START;
+ isp_frame_process ();
+ break;
+ }
+}
+
+void
+isp_frame_send_frame (uint8_t *data, uint16_t len)
+{
+ uint8_t cksum;
+ AC_ISP_FRAME_SEND_CHAR (ISP_FRAME_PROTO_START);
+ cksum = ISP_FRAME_PROTO_START;
+ AC_ISP_FRAME_SEND_CHAR (isp_frame_global.seq);
+ cksum ^= isp_frame_global.seq;
+ AC_ISP_FRAME_SEND_CHAR (len >> 8);
+ cksum ^= len >> 8;
+ AC_ISP_FRAME_SEND_CHAR (len & 0xff);
+ cksum ^= len & 0xff;
+ AC_ISP_FRAME_SEND_CHAR (ISP_FRAME_PROTO_TOKEN);
+ cksum ^= ISP_FRAME_PROTO_TOKEN;
+ for (; len; len--)
+ {
+ AC_ISP_FRAME_SEND_CHAR (*data);
+ cksum ^= *data;
+ data++;
+ }
+ AC_ISP_FRAME_SEND_CHAR (cksum);
+}
+
+static void
+isp_frame_process (void)
+{
+ if (isp_frame_global.cksum != 0)
+ {
+ /* Bad checksum. */
+ uint8_t answer[2];
+ answer[0] = ISP_FRAME_PROTO_ANSWER_CKSUM_ERROR;
+ answer[1] = ISP_FRAME_PROTO_STATUS_CKSUM_ERROR;
+ isp_frame_send_frame (answer, 2);
+ }
+ else
+ {
+ AC_ISP_FRAME_ACCEPT_FRAME (isp_frame_global.buffer,
+ isp_frame_global.buffer_len,
+ AC_ISP_FRAME_BUFFER_SIZE);
+ }
+}
+