/* Each block in FIFO can contain up to pending_queue_len transfers */
static unsigned int pending_queue_len;
+static unsigned int tfer_max_command_size;
+static unsigned int tfer_max_response_size;
/* pointers to buffers that will receive jtag scan results on the next flush */
#define MAX_PENDING_SCAN_RESULTS 256
return ERROR_OK;
}
+
static void cmsis_dap_swd_write_from_queue(struct cmsis_dap *dap)
{
uint8_t *command = dap->command;
struct pending_request_block *block = &dap->pending_fifo[dap->pending_fifo_put_idx];
+ assert(dap->write_count + dap->read_count == block->transfer_count);
+
+ /* Reset packet size check counters for the next packet */
+ dap->write_count = 0;
+ dap->read_count = 0;
+
LOG_DEBUG_IO("Executing %d queued transactions from FIFO index %u",
block->transfer_count, dap->pending_fifo_put_idx);
return retval;
}
+static unsigned int cmsis_dap_tfer_cmd_size(unsigned int write_count,
+ unsigned int read_count)
+{
+ unsigned int size = 3; /* header */
+ size += write_count * (1 + 4); /* DAP register + data */
+ size += read_count; /* DAP register */
+ return size;
+}
+
+static unsigned int cmsis_dap_tfer_resp_size(unsigned int write_count,
+ unsigned int read_count)
+{
+ unsigned int size = 3; /* header */
+ size += read_count * 4; /* data */
+ return size;
+}
+
static void cmsis_dap_swd_queue_cmd(uint8_t cmd, uint32_t *dst, uint32_t data)
{
+ /* Compute sizes of the DAP Transfer command and the expected response
+ * for all queued and this operation */
bool targetsel_cmd = swd_cmd(false, false, DP_TARGETSEL) == cmd;
- if (cmsis_dap_handle->pending_fifo[cmsis_dap_handle->pending_fifo_put_idx].transfer_count == pending_queue_len
+ unsigned int write_count = cmsis_dap_handle->write_count;
+ unsigned int read_count = cmsis_dap_handle->read_count;
+ if (cmd & SWD_CMD_RNW)
+ read_count++;
+ else
+ write_count++;
+
+ unsigned int cmd_size = cmsis_dap_tfer_cmd_size(write_count, read_count);
+ unsigned int resp_size = cmsis_dap_tfer_resp_size(write_count, read_count);
+
+ /* Does the DAP Transfer command and the expected response fit into one packet?
+ * Run the queue also before a targetsel - it cannot be queued */
+ if (cmd_size > tfer_max_command_size
+ || resp_size > tfer_max_response_size
|| targetsel_cmd) {
if (cmsis_dap_handle->pending_fifo_block_count)
cmsis_dap_swd_read_process(cmsis_dap_handle, 0);
cmsis_dap_swd_read_process(cmsis_dap_handle, LIBUSB_TIMEOUT_MS);
}
+ assert(cmsis_dap_handle->pending_fifo[cmsis_dap_handle->pending_fifo_put_idx].transfer_count < pending_queue_len);
+
if (queued_retval != ERROR_OK)
return;
if (cmd & SWD_CMD_RNW) {
/* Queue a read transaction */
transfer->buffer = dst;
+ cmsis_dap_handle->read_count++;
+ } else {
+ cmsis_dap_handle->write_count++;
}
block->transfer_count++;
}
/* Be conservative and suppress submitting multiple HID requests
* until we get packet count info from the adaptor */
cmsis_dap_handle->packet_count = 1;
- pending_queue_len = 12;
/* INFO_ID_PKT_SZ - short */
retval = cmsis_dap_cmd_dap_info(INFO_ID_PKT_SZ, &data);
if (data[0] == 2) { /* short */
uint16_t pkt_sz = data[1] + (data[2] << 8);
if (pkt_sz != cmsis_dap_handle->packet_size) {
-
- /* 4 bytes of command header + 5 bytes per register
- * write. For bulk read sequences just 4 bytes are
- * needed per transfer, so this is suboptimal. */
- pending_queue_len = (pkt_sz - 4) / 5;
-
free(cmsis_dap_handle->packet_buffer);
retval = cmsis_dap_handle->backend->packet_buffer_alloc(cmsis_dap_handle, pkt_sz);
if (retval != ERROR_OK)
}
}
+ /* Maximal number of transfers which fit to one packet:
+ * Limited by response size: 3 bytes of response header + 4 per read
+ * Plus writes to full command size: 3 bytes cmd header + 1 per read + 5 per write */
+ tfer_max_command_size = cmsis_dap_handle->packet_usable_size;
+ tfer_max_response_size = cmsis_dap_handle->packet_usable_size;
+ unsigned int max_reads = tfer_max_response_size / 4;
+ pending_queue_len = max_reads + (tfer_max_command_size - max_reads) / 5;
+ cmsis_dap_handle->write_count = 0;
+ cmsis_dap_handle->read_count = 0;
+
/* INFO_ID_PKT_CNT - byte */
retval = cmsis_dap_cmd_dap_info(INFO_ID_PKT_CNT, &data);
if (retval != ERROR_OK)