[PATCH 09/11] firewire-sbp-target: Add sbp_target_agent.{c,h}

[Chris Boot <bootc@bootc.net>]

This implements the SBP-2 Command Block Agent, or Target Agent. This is
what receives SCSI commands and forwards them to the target framework.

Signed-off-by: Chris Boot <bootc@bootc.net>
Cc: Andy Grover <agrover@redhat.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
---
 drivers/target/sbp/sbp_target_agent.c |  395 +++++++++++++++++++++++++++++++++
 drivers/target/sbp/sbp_target_agent.h |   40 ++++
 2 files changed, 435 insertions(+)
 create mode 100644 drivers/target/sbp/sbp_target_agent.c
 create mode 100644 drivers/target/sbp/sbp_target_agent.h

diff --git a/drivers/target/sbp/sbp_target_agent.c b/drivers/target/sbp/sbp_target_agent.c
new file mode 100644
index 0000000..5fdd401
--- /dev/null
+++ b/drivers/target/sbp/sbp_target_agent.c
@@ -0,0 +1,395 @@
+/*
+ * SBP2 target driver (SCSI over IEEE1394 in target mode)
+ *
+ * Copyright (C) 2011  Chris Boot <bootc@bootc.net>
+ *
+ * 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.
+ */
+
+#define KMSG_COMPONENT "sbp_target"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/slab.h>
+
+#include <target/target_core_base.h>
+
+#include "sbp_base.h"
+#include "sbp_management_agent.h"
+#include "sbp_login.h"
+#include "sbp_target_agent.h"
+#include "sbp_scsi_cmnd.h"
+
+static int tgt_agent_rw_agent_state(struct fw_card *card, int tcode, void *data,
+		struct sbp_target_agent *agent)
+{
+	__be32 state;
+
+	switch (tcode) {
+	case TCODE_READ_QUADLET_REQUEST:
+		pr_debug("tgt_agent AGENT_STATE READ\n");
+
+		spin_lock_bh(&agent->lock);
+		state = cpu_to_be32(agent->state);
+		spin_unlock_bh(&agent->lock);
+		memcpy(data, &state, sizeof(state));
+
+		return RCODE_COMPLETE;
+
+	case TCODE_WRITE_QUADLET_REQUEST:
+		/* ignored */
+		return RCODE_COMPLETE;
+
+	default:
+		return RCODE_TYPE_ERROR;
+	}
+}
+
+static int tgt_agent_rw_agent_reset(struct fw_card *card, int tcode, void *data,
+		struct sbp_target_agent *agent)
+{
+	switch (tcode) {
+	case TCODE_WRITE_QUADLET_REQUEST:
+		pr_debug("tgt_agent AGENT_RESET\n");
+		spin_lock_bh(&agent->lock);
+		agent->state = AGENT_STATE_RESET;
+		spin_unlock_bh(&agent->lock);
+		return RCODE_COMPLETE;
+
+	default:
+		return RCODE_TYPE_ERROR;
+	}
+}
+
+static int tgt_agent_rw_orb_pointer(struct fw_card *card, int tcode, void *data,
+		struct sbp_target_agent *agent)
+{
+	struct sbp2_pointer *ptr = data;
+
+	switch (tcode) {
+	case TCODE_WRITE_BLOCK_REQUEST:
+		spin_lock_bh(&agent->lock);
+		if (agent->state != AGENT_STATE_SUSPENDED &&
+				agent->state != AGENT_STATE_RESET) {
+			spin_unlock_bh(&agent->lock);
+			pr_notice("Ignoring ORB_POINTER write while active.\n");
+			return RCODE_CONFLICT_ERROR;
+		}
+		agent->state = AGENT_STATE_ACTIVE;
+		spin_unlock_bh(&agent->lock);
+
+		agent->orb_pointer = sbp2_pointer_to_addr(ptr);
+		agent->doorbell = false;
+
+		pr_debug("tgt_agent ORB_POINTER write: 0x%llx\n",
+				agent->orb_pointer);
+
+		queue_work(system_unbound_wq, &agent->work);
+
+		return RCODE_COMPLETE;
+
+	case TCODE_READ_BLOCK_REQUEST:
+		pr_debug("tgt_agent ORB_POINTER READ\n");
+		spin_lock_bh(&agent->lock);
+		addr_to_sbp2_pointer(agent->orb_pointer, ptr);
+		spin_unlock_bh(&agent->lock);
+		return RCODE_COMPLETE;
+
+	default:
+		return RCODE_TYPE_ERROR;
+	}
+}
+
+static int tgt_agent_rw_doorbell(struct fw_card *card, int tcode, void *data,
+		struct sbp_target_agent *agent)
+{
+	switch (tcode) {
+	case TCODE_WRITE_QUADLET_REQUEST:
+		spin_lock_bh(&agent->lock);
+		if (agent->state != AGENT_STATE_SUSPENDED) {
+			spin_unlock_bh(&agent->lock);
+			pr_debug("Ignoring DOORBELL while active.\n");
+			return RCODE_CONFLICT_ERROR;
+		}
+		agent->state = AGENT_STATE_ACTIVE;
+		spin_unlock_bh(&agent->lock);
+
+		agent->doorbell = true;
+
+		pr_debug("tgt_agent DOORBELL\n");
+
+		queue_work(system_unbound_wq, &agent->work);
+
+		return RCODE_COMPLETE;
+
+	case TCODE_READ_QUADLET_REQUEST:
+		return RCODE_COMPLETE;
+
+	default:
+		return RCODE_TYPE_ERROR;
+	}
+}
+
+static int tgt_agent_rw_unsolicited_status_enable(struct fw_card *card,
+		int tcode, void *data, struct sbp_target_agent *agent)
+{
+	switch (tcode) {
+	case TCODE_WRITE_QUADLET_REQUEST:
+		pr_debug("tgt_agent UNSOLICITED_STATUS_ENABLE\n");
+		/* ignored as we don't send unsolicited status */
+		return RCODE_COMPLETE;
+
+	case TCODE_READ_QUADLET_REQUEST:
+		return RCODE_COMPLETE;
+
+	default:
+		return RCODE_TYPE_ERROR;
+	}
+}
+
+static void tgt_agent_rw(struct fw_card *card, struct fw_request *request,
+		int tcode, int destination, int source, int generation,
+		unsigned long long offset, void *data, size_t length,
+		void *callback_data)
+{
+	struct sbp_target_agent *agent = callback_data;
+	struct sbp_session *sess = agent->login->sess;
+	int sess_gen, sess_node, rcode;
+
+	spin_lock_bh(&sess->lock);
+	sess_gen = sess->generation;
+	sess_node = sess->node_id;
+	spin_unlock_bh(&sess->lock);
+
+	if (generation != sess_gen) {
+		pr_notice("ignoring request with wrong generation\n");
+		rcode = RCODE_TYPE_ERROR;
+		goto out;
+	}
+
+	if (source != sess_node) {
+		pr_notice("ignoring request from foreign node (%x != %x)\n",
+				source, sess_node);
+		rcode = RCODE_TYPE_ERROR;
+		goto out;
+	}
+
+	/* turn offset into the offset from the start of the block */
+	offset -= agent->handler.offset;
+
+	if (offset == 0x00 && length == 4) {
+		/* AGENT_STATE */
+		rcode = tgt_agent_rw_agent_state(card, tcode, data, agent);
+	} else if (offset == 0x04 && length == 4) {
+		/* AGENT_RESET */
+		rcode = tgt_agent_rw_agent_reset(card, tcode, data, agent);
+	} else if (offset == 0x08 && length == 8) {
+		/* ORB_POINTER */
+		rcode = tgt_agent_rw_orb_pointer(card, tcode, data, agent);
+	} else if (offset == 0x10 && length == 4) {
+		/* DOORBELL */
+		rcode = tgt_agent_rw_doorbell(card, tcode, data, agent);
+	} else if (offset == 0x14 && length == 4) {
+		/* UNSOLICITED_STATUS_ENABLE */
+		rcode = tgt_agent_rw_unsolicited_status_enable(card, tcode,
+				data, agent);
+	} else {
+		rcode = RCODE_ADDRESS_ERROR;
+	}
+
+out:
+	fw_send_response(card, request, rcode);
+}
+
+static void tgt_agent_process_work(struct work_struct *work)
+{
+	struct sbp_target_request *req =
+		container_of(work, struct sbp_target_request, work);
+
+	pr_debug("tgt_orb ptr:0x%llx next_ORB:0x%llx data_descriptor:0x%llx misc:0x%x\n",
+			req->orb_pointer,
+			sbp2_pointer_to_addr(&req->orb.next_orb),
+			sbp2_pointer_to_addr(&req->orb.data_descriptor),
+			be32_to_cpu(req->orb.misc));
+
+	if (req->orb_pointer >> 32)
+		pr_debug("ORB with high bits set\n");
+
+	switch (ORB_REQUEST_FORMAT(be32_to_cpu(req->orb.misc))) {
+		case 0:/* Format specified by this standard */
+			sbp_handle_command(req);
+			return;
+		case 1: /* Reserved for future standardization */
+		case 2: /* Vendor-dependent */
+			req->status.status |= cpu_to_be32(
+					STATUS_BLOCK_RESP(
+						STATUS_RESP_REQUEST_COMPLETE) |
+					STATUS_BLOCK_DEAD(0) |
+					STATUS_BLOCK_LEN(1) |
+					STATUS_BLOCK_SBP_STATUS(
+						SBP_STATUS_REQ_TYPE_NOTSUPP));
+			sbp_send_status(req);
+			sbp_free_request(req);
+			return;
+		case 3: /* Dummy ORB */
+			req->status.status |= cpu_to_be32(
+					STATUS_BLOCK_RESP(
+						STATUS_RESP_REQUEST_COMPLETE) |
+					STATUS_BLOCK_DEAD(0) |
+					STATUS_BLOCK_LEN(1) |
+					STATUS_BLOCK_SBP_STATUS(
+						SBP_STATUS_DUMMY_ORB_COMPLETE));
+			sbp_send_status(req);
+			sbp_free_request(req);
+			return;
+		default:
+			BUG();
+	}
+}
+
+/* used to double-check we haven't been issued an AGENT_RESET */
+static inline bool tgt_agent_check_active(struct sbp_target_agent *agent)
+{
+	bool active;
+
+	spin_lock_bh(&agent->lock);
+	active = (agent->state == AGENT_STATE_ACTIVE);
+	spin_unlock_bh(&agent->lock);
+
+	return active;
+}
+
+static void tgt_agent_fetch_work(struct work_struct *work)
+{
+	struct sbp_target_agent *agent =
+		container_of(work, struct sbp_target_agent, work);
+	struct sbp_session *sess = agent->login->sess;
+	struct sbp_target_request *req;
+	int ret;
+	bool doorbell = agent->doorbell;
+	u64 next_orb = agent->orb_pointer;
+
+	while (next_orb && tgt_agent_check_active(agent)) {
+		req = kzalloc(sizeof(*req), GFP_KERNEL);
+		if (!req) {
+			spin_lock_bh(&agent->lock);
+			agent->state = AGENT_STATE_DEAD;
+			spin_unlock_bh(&agent->lock);
+			return;
+		}
+
+		req->login = agent->login;
+		req->orb_pointer = next_orb;
+
+		req->status.status = cpu_to_be32(STATUS_BLOCK_ORB_OFFSET_HIGH(
+					req->orb_pointer >> 32));
+		req->status.orb_low = cpu_to_be32(
+				req->orb_pointer & 0xfffffffc);
+
+		/* read in the ORB */
+		ret = sbp_run_transaction(sess->card, TCODE_READ_BLOCK_REQUEST,
+				sess->node_id, sess->generation, sess->speed,
+				req->orb_pointer, &req->orb, sizeof(req->orb));
+		if (ret != RCODE_COMPLETE) {
+			pr_debug("tgt_orb fetch failed: %x\n", ret);
+			req->status.status |= cpu_to_be32(
+					STATUS_BLOCK_SRC(
+						STATUS_SRC_ORB_FINISHED) |
+					STATUS_BLOCK_RESP(
+						STATUS_RESP_TRANSPORT_FAILURE) |
+					STATUS_BLOCK_DEAD(1) |
+					STATUS_BLOCK_LEN(1) |
+					STATUS_BLOCK_SBP_STATUS(
+						SBP_STATUS_UNSPECIFIED_ERROR));
+			spin_lock_bh(&agent->lock);
+			agent->state = AGENT_STATE_DEAD;
+			spin_unlock_bh(&agent->lock);
+
+			sbp_send_status(req);
+			sbp_free_request(req);
+			return;
+		}
+
+		/* check the next_ORB field */
+		if (be32_to_cpu(req->orb.next_orb.high) & 0x80000000) {
+			next_orb = 0;
+			req->status.status |= cpu_to_be32(STATUS_BLOCK_SRC(
+						STATUS_SRC_ORB_FINISHED));
+		} else {
+			next_orb = sbp2_pointer_to_addr(&req->orb.next_orb);
+			req->status.status |= cpu_to_be32(STATUS_BLOCK_SRC(
+						STATUS_SRC_ORB_CONTINUING));
+		}
+
+		if (tgt_agent_check_active(agent) && !doorbell) {
+			INIT_WORK(&req->work, tgt_agent_process_work);
+			queue_work(system_unbound_wq, &req->work);
+		} else {
+			/* don't process this request, just check next_ORB */
+			sbp_free_request(req);
+		} 
+
+		spin_lock_bh(&agent->lock);
+		doorbell = agent->doorbell = false;
+
+		/* check if we should carry on processing */
+		if (next_orb)
+			agent->orb_pointer = next_orb;
+		else
+			agent->state = AGENT_STATE_SUSPENDED;
+
+		spin_unlock_bh(&agent->lock);
+	};
+}
+
+struct sbp_target_agent *sbp_target_agent_register(
+		struct sbp_login_descriptor *login)
+{
+	struct sbp_target_agent *agent;
+	int ret;
+
+	agent = kmalloc(sizeof(*agent), GFP_KERNEL);
+	if (!agent)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&agent->lock);
+
+	agent->handler.length = 0x20;
+	agent->handler.address_callback = tgt_agent_rw;
+	agent->handler.callback_data = agent;
+
+	agent->login = login;
+	agent->state = AGENT_STATE_RESET;
+	INIT_WORK(&agent->work, tgt_agent_fetch_work);
+	agent->orb_pointer = 0;
+	agent->doorbell = false;
+
+	ret = fw_core_add_address_handler(&agent->handler,
+			&sbp_register_region);
+	if (ret < 0) {
+		kfree(agent);
+		return ERR_PTR(ret);
+	}
+
+	return agent;
+}
+
+void sbp_target_agent_unregister(struct sbp_target_agent *agent)
+{
+	fw_core_remove_address_handler(&agent->handler);
+	cancel_work_sync(&agent->work);
+	kfree(agent);
+}
diff --git a/drivers/target/sbp/sbp_target_agent.h b/drivers/target/sbp/sbp_target_agent.h
new file mode 100644
index 0000000..b5d76fd
--- /dev/null
+++ b/drivers/target/sbp/sbp_target_agent.h
@@ -0,0 +1,40 @@
+#ifndef _SBP_TARGET_AGENT_H
+#define _SBP_TARGET_AGENT_H
+
+#include <linux/firewire.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <target/target_core_base.h>
+
+#include "sbp_base.h"
+
+struct sbp_target_agent {
+	spinlock_t lock;
+	struct fw_address_handler handler;
+	struct sbp_login_descriptor *login;
+	int state;
+	struct work_struct work;
+	u64 orb_pointer;
+	bool doorbell;
+};
+
+struct sbp_target_request {
+	struct sbp_login_descriptor *login;
+	u64 orb_pointer;
+	struct sbp_command_block_orb orb;
+	struct sbp_status_block status;
+	struct work_struct work;
+
+	struct se_cmd se_cmd;
+	struct sbp_page_table_entry *pg_tbl;
+	void *cmd_buf;
+
+	unsigned char sense_buf[TRANSPORT_SENSE_BUFFER];
+};
+
+struct sbp_target_agent *sbp_target_agent_register(
+		struct sbp_login_descriptor *login);
+void sbp_target_agent_unregister(struct sbp_target_agent *agent);
+
+#endif
-- 
1.7.9.5