1 files changed, 272 insertions, 0 deletions
diff --git a/drivers/net/ixp2000/ixp2400_tx.uc b/drivers/net/ixp2000/ixp2400_tx.uc
new file mode 100644
index 0000000..d090d18
--- /dev/null
+++ b/drivers/net/ixp2000/ixp2400_tx.uc
@@ -0,0 +1,272 @@
+/*
+ * TX ucode for the Intel IXP2400 in POS-PHY mode.
+ * Copyright (C) 2004, 2005 Lennert Buytenhek
+ * Dedicated to Marija Kulikova.
+ *
+ * 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.
+ *
+ * Assumptions made in this code:
+ * - The IXP2400 MSF is configured for POS-PHY mode, in a mode where
+ *   only one TBUF partition is used.  This includes, for example,
+ *   1x32 SPHY and 1x32 MPHY32, but not 4x8 SPHY or 1x32 MPHY4. (This
+ *   is not an exhaustive list.)
+ * - The TBUF uses 64-byte mpackets.
+ * - TX descriptors reside in SRAM, and have the following format:
+ *	struct tx_desc
+ *	{
+ *	// to uengine
+ *		u32	buf_phys_addr;
+ *		u32	pkt_length;
+ *		u32	channel;
+ *	};
+ * - Packet data resides in DRAM.
+ * - Packet buffer addresses are 8-byte aligned.
+ * - Scratch ring 2 is tx_pending.
+ * - Scratch ring 3 is tx_done, and has status condition 'full'.
+ * - This code is run on all eight threads of the microengine it runs on.
+ */
+
+#define TX_SEQUENCE_0		0x0060
+#define TBUF_CTRL		0x1800
+
+#define PARTITION_SIZE		128
+#define PARTITION_THRESH	96
+
+
+	.sig volatile sig1
+	.sig volatile sig2
+	.sig volatile sig3
+
+	.reg @old_tx_seq_0
+	.reg @mpkts_in_flight
+	.reg @next_tbuf_mpacket
+
+	.reg @buffer_handle
+	.reg @buffer_start
+	.reg @packet_length
+	.reg @channel
+	.reg @packet_offset
+
+	.reg zero
+
+	immed[zero, 0]
+
+	/*
+	 * Skip context 0 initialisation?
+	 */
+	.begin
+		br!=ctx[0, mpacket_tx_loop#]
+	.end
+
+	/*
+	 * Wait until all pending TBUF elements have been transmitted.
+	 */
+	.begin
+		.reg read $tx
+		.sig zzz
+
+	loop_empty#:
+		msf[read, $tx, zero, TX_SEQUENCE_0, 1], ctx_swap[zzz]
+		alu_shf[--, --, b, $tx, >>31]
+		beq[loop_empty#]
+
+		alu[@old_tx_seq_0, --, b, $tx]
+	.end
+
+	immed[@mpkts_in_flight, 0]
+	alu[@next_tbuf_mpacket, @old_tx_seq_0, and, (PARTITION_SIZE - 1)]
+
+	immed[@buffer_handle, 0]
+
+	/*
+	 * Initialise signal pipeline.
+	 */
+	.begin
+		local_csr_wr[SAME_ME_SIGNAL, (&sig1 << 3)]
+		.set_sig sig1
+
+		local_csr_wr[SAME_ME_SIGNAL, (&sig2 << 3)]
+		.set_sig sig2
+
+		local_csr_wr[SAME_ME_SIGNAL, (&sig3 << 3)]
+		.set_sig sig3
+	.end
+
+mpacket_tx_loop#:
+	.begin
+		.reg tbuf_element_index
+		.reg buffer_handle
+		.reg sop_eop
+		.reg packet_data
+		.reg channel
+		.reg mpacket_size
+
+		/*
+		 * If there is no packet currently being transmitted,
+		 * dequeue the next TX descriptor, and fetch the buffer
+		 * address, packet length and destination channel number.
+		 */
+		.begin
+			.reg read $stemp $stemp2 $stemp3
+			.xfer_order $stemp $stemp2 $stemp3
+			.sig zzz
+
+			ctx_arb[sig1]
+
+			alu[--, --, b, @buffer_handle]
+			bne[already_got_packet#]
+
+		tx_nobufs#:
+			scratch[get, $stemp, zero, 8, 1], ctx_swap[zzz]
+			alu[@buffer_handle, --, b, $stemp]
+			beq[tx_nobufs#]
+
+			sram[read, $stemp, $stemp, 0, 3], ctx_swap[zzz]
+			alu[@buffer_start, --, b, $stemp]
+			alu[@packet_length, --, b, $stemp2]
+			beq[zero_byte_packet#]
+			alu[@channel, --, b, $stemp3]
+			immed[@packet_offset, 0]
+
+		already_got_packet#:
+			local_csr_wr[SAME_ME_SIGNAL, (0x80 | (&sig1 << 3))]
+		.end
+
+		/*
+		 * Determine tbuf element index, SOP/EOP flags, mpacket
+		 * offset and mpacket size and cache buffer_handle and
+		 * channel number.
+		 */
+		.begin
+			alu[tbuf_element_index, --, b, @next_tbuf_mpacket]
+			alu[@next_tbuf_mpacket, @next_tbuf_mpacket, +, 1]
+			alu[@next_tbuf_mpacket, @next_tbuf_mpacket, and,
+							(PARTITION_SIZE - 1)]
+
+			alu[buffer_handle, --, b, @buffer_handle]
+			immed[@buffer_handle, 0]
+
+			immed[sop_eop, 1]
+
+			alu[packet_data, --, b, @packet_offset]
+			bne[no_sop#]
+			alu[sop_eop, sop_eop, or, 2]
+		no_sop#:
+			alu[packet_data, packet_data, +, @buffer_start]
+
+			alu[channel, --, b, @channel]
+
+			alu[mpacket_size, @packet_length, -, @packet_offset]
+			alu[--, 64, -, mpacket_size]
+			bhs[eop#]
+			alu[@buffer_handle, --, b, buffer_handle]
+			immed[mpacket_size, 64]
+			alu[sop_eop, sop_eop, and, 2]
+		eop#:
+
+			alu[@packet_offset, @packet_offset, +, mpacket_size]
+		.end
+
+		/*
+		 * Wait until there's enough space in the TBUF.
+		 */
+		.begin
+			.reg read $tx
+			.reg temp
+			.sig zzz
+
+			ctx_arb[sig2]
+
+			br[test_space#]
+
+		loop_space#:
+			msf[read, $tx, zero, TX_SEQUENCE_0, 1], ctx_swap[zzz]
+
+			alu[temp, $tx, -, @old_tx_seq_0]
+			alu[temp, temp, and, 0xff]
+			alu[@mpkts_in_flight, @mpkts_in_flight, -, temp]
+
+			alu[@old_tx_seq_0, --, b, $tx]
+
+		test_space#:
+			alu[--, PARTITION_THRESH, -, @mpkts_in_flight]
+			blo[loop_space#]
+
+			alu[@mpkts_in_flight, @mpkts_in_flight, +, 1]
+
+			local_csr_wr[SAME_ME_SIGNAL, (0x80 | (&sig2 << 3))]
+		.end
+
+		/*
+		 * Copy the packet data to the TBUF.
+		 */
+		.begin
+			.reg temp
+			.sig copy_sig
+
+			alu[temp, mpacket_size, -, 1]
+			alu_shf[temp, 0x10, or, temp, >>3]
+			alu_shf[temp, 0x10, or, temp, <<21]
+			alu_shf[temp, temp, or, tbuf_element_index, <<11]
+			alu_shf[--, temp, or, 1, <<18]
+
+			dram[tbuf_wr, --, packet_data, 0, max_8],
+					indirect_ref, sig_done[copy_sig]
+			ctx_arb[copy_sig]
+		.end
+
+		/*
+		 * Mark TBUF element as ready-to-be-transmitted.
+		 */
+		.begin
+			.reg write $tsw $tsw2
+			.xfer_order $tsw $tsw2
+			.reg temp
+			.sig zzz
+
+			alu_shf[temp, channel, or, mpacket_size, <<24]
+			alu_shf[$tsw, temp, or, sop_eop, <<8]
+			immed[$tsw2, 0]
+
+			immed[temp, TBUF_CTRL]
+			alu_shf[temp, temp, or, tbuf_element_index, <<3]
+			msf[write, $tsw, temp, 0, 2], ctx_swap[zzz]
+		.end
+
+		/*
+		 * Resynchronise.
+		 */
+		.begin
+			ctx_arb[sig3]
+			local_csr_wr[SAME_ME_SIGNAL, (0x80 | (&sig3 << 3))]
+		.end
+
+		/*
+		 * If this was an EOP mpacket, recycle the TX buffer
+	 	 * and signal the host.
+		 */
+		.begin
+			.reg write $stemp
+			.sig zzz
+
+			alu[--, sop_eop, and, 1]
+			beq[mpacket_tx_loop#]
+
+		tx_done_ring_full#:
+			br_inp_state[SCR_Ring3_Status, tx_done_ring_full#]
+
+			alu[$stemp, --, b, buffer_handle]
+			scratch[put, $stemp, zero, 12, 1], ctx_swap[zzz]
+			cap[fast_wr, 0, XSCALE_INT_A]
+			br[mpacket_tx_loop#]
+		.end
+	.end
+
+
+zero_byte_packet#:
+	halt
+
+