1 files changed, 76 insertions, 308 deletions

diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 5156b88b0f2a..625f1eb80698 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -404,15 +404,15 @@ static int sbp2util_access_timeout(struct scsi_id_instance_data *scsi_id,
         return leftover <= 0;
 }
 
-/* Frees an allocated packet */
 static void sbp2_free_packet(struct hpsb_packet *packet)
 {
         hpsb_free_tlabel(packet);
         hpsb_free_packet(packet);
 }
 
-/* This is much like hpsb_node_write(), except it ignores the response
- * subaction and returns immediately. Can be used from interrupts.
+/*
+ * This is much like hpsb_node_write(), except it ignores the response
+ * subaction and returns immediately. Can be used from atomic context.
  */
 static int sbp2util_node_write_no_wait(struct node_entry *ne, u64 addr,
                                        quadlet_t *buffer, size_t length)
@@ -476,10 +476,6 @@ static void sbp2util_write_doorbell(struct work_struct *work)
         sbp2util_notify_fetch_agent(container_of(work, struct scsi_id_instance_data, protocol_work), SBP2_DOORBELL_OFFSET, NULL, 4);
 }
 
-/*
- * This function is called to create a pool of command orbs used for
- * command processing. It is called when a new sbp2 device is detected.
- */
 static int sbp2util_create_command_orb_pool(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
@@ -513,9 +509,6 @@ static int sbp2util_create_command_orb_pool(struct scsi_id_instance_data *scsi_i
         return 0;
 }
 
-/*
- * This function is called to delete a pool of command orbs.
- */
 static void sbp2util_remove_command_orb_pool(struct scsi_id_instance_data *scsi_id)
 {
         struct hpsb_host *host = scsi_id->hi->host;
@@ -527,8 +520,6 @@ static void sbp2util_remove_command_orb_pool(struct scsi_id_instance_data *scsi_
         if (!list_empty(&scsi_id->sbp2_command_orb_completed)) {
                 list_for_each_safe(lh, next, &scsi_id->sbp2_command_orb_completed) {
                         command = list_entry(lh, struct sbp2_command_info, list);
-
-                        /* Release our generic DMA's */
                         pci_unmap_single(host->pdev, command->command_orb_dma,
                                          sizeof(struct sbp2_command_orb),
                                          PCI_DMA_TODEVICE);
@@ -543,8 +534,8 @@ static void sbp2util_remove_command_orb_pool(struct scsi_id_instance_data *scsi_
 }
 
 /*
- * This function finds the sbp2_command for a given outstanding command
- * orb.Only looks at the inuse list.
+ * Finds the sbp2_command for a given outstanding command ORB.
+ * Only looks at the in-use list.
  */
 static struct sbp2_command_info *sbp2util_find_command_for_orb(
                 struct scsi_id_instance_data *scsi_id, dma_addr_t orb)
@@ -566,8 +557,8 @@ static struct sbp2_command_info *sbp2util_find_command_for_orb(
 }
 
 /*
- * This function finds the sbp2_command for a given outstanding SCpnt.
- * Only looks at the inuse list.
+ * Finds the sbp2_command for a given outstanding SCpnt.
+ * Only looks at the in-use list.
  * Must be called with scsi_id->sbp2_command_orb_lock held.
  */
 static struct sbp2_command_info *sbp2util_find_command_for_SCpnt(
@@ -582,9 +573,6 @@ static struct sbp2_command_info *sbp2util_find_command_for_SCpnt(
         return NULL;
 }
 
-/*
- * This function allocates a command orb used to send a scsi command.
- */
 static struct sbp2_command_info *sbp2util_allocate_command_orb(
                 struct scsi_id_instance_data *scsi_id,
                 struct scsi_cmnd *Current_SCpnt,
@@ -609,7 +597,6 @@ static struct sbp2_command_info *sbp2util_allocate_command_orb(
         return command;
 }
 
-/* Free our DMA's */
 static void sbp2util_free_command_dma(struct sbp2_command_info *command)
 {
         struct scsi_id_instance_data *scsi_id =
@@ -705,7 +692,7 @@ static int sbp2_remove(struct device *dev)
                  * send them. */
                 if (!sbp2util_node_is_available(scsi_id))
                         sbp2scsi_complete_all_commands(scsi_id, DID_NO_CONNECT);
-                /* scsi_remove_device() will trigger shutdown functions of SCSI
+                /* scsi_remove_device() may trigger shutdown functions of SCSI
                  * highlevel drivers which would deadlock if blocked. */
                 atomic_set(&scsi_id->state, SBP2LU_STATE_IN_SHUTDOWN);
                 scsi_unblock_requests(scsi_id->scsi_host);
@@ -727,12 +714,9 @@ static int sbp2_update(struct unit_directory *ud)
         struct scsi_id_instance_data *scsi_id = ud->device.driver_data;
 
         if (sbp2_reconnect_device(scsi_id)) {
-
-                /*
-                 * Ok, reconnect has failed. Perhaps we didn't
-                 * reconnect fast enough. Try doing a regular login, but
-                 * first do a logout just in case of any weirdness.
-                 */
+                /* Reconnect has failed. Perhaps we didn't reconnect fast
+                 * enough. Try a regular login, but first log out just in
+                 * case of any weirdness. */
                 sbp2_logout_device(scsi_id);
 
                 if (sbp2_login_device(scsi_id)) {
@@ -743,18 +727,12 @@ static int sbp2_update(struct unit_directory *ud)
                 }
         }
 
-        /* Set max retries to something large on the device. */
         sbp2_set_busy_timeout(scsi_id);
-
-        /* Do a SBP-2 fetch agent reset. */
         sbp2_agent_reset(scsi_id, 1);
-
-        /* Get the max speed and packet size that we can use. */
         sbp2_max_speed_and_size(scsi_id);
 
-        /* Complete any pending commands with busy (so they get
-         * retried) and remove them from our queue
-         */
+        /* Complete any pending commands with busy (so they get retried)
+         * and remove them from our queue. */
         sbp2scsi_complete_all_commands(scsi_id, DID_BUS_BUSY);
 
         /* Accept new commands unless there was another bus reset in the
@@ -766,8 +744,6 @@ static int sbp2_update(struct unit_directory *ud)
         return 0;
 }
 
-/* This functions is called by the sbp2_probe, for each new device. We now
- * allocate one scsi host for each scsi_id (unit directory). */
 static struct scsi_id_instance_data *sbp2_alloc_device(struct unit_directory *ud)
 {
         struct sbp2scsi_host_info *hi;
@@ -843,7 +819,6 @@ static struct scsi_id_instance_data *sbp2_alloc_device(struct unit_directory *ud
                 goto failed_alloc;
         }
 
-        /* Register our host with the SCSI stack. */
         scsi_host = scsi_host_alloc(&scsi_driver_template,
                                     sizeof(unsigned long));
         if (!scsi_host) {
@@ -882,16 +857,11 @@ static void sbp2_host_reset(struct hpsb_host *host)
                 }
 }
 
-/*
- * This function is where we first pull the node unique ids, and then
- * allocate memory and register a SBP-2 device.
- */
 static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
         int error;
 
-        /* Login FIFO DMA */
         scsi_id->login_response =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_login_response),
@@ -899,7 +869,6 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->login_response)
                 goto alloc_fail;
 
-        /* Query logins ORB DMA */
         scsi_id->query_logins_orb =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_query_logins_orb),
@@ -907,7 +876,6 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->query_logins_orb)
                 goto alloc_fail;
 
-        /* Query logins response DMA */
         scsi_id->query_logins_response =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_query_logins_response),
@@ -915,7 +883,6 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->query_logins_response)
                 goto alloc_fail;
 
-        /* Reconnect ORB DMA */
         scsi_id->reconnect_orb =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_reconnect_orb),
@@ -923,7 +890,6 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->reconnect_orb)
                 goto alloc_fail;
 
-        /* Logout ORB DMA */
         scsi_id->logout_orb =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_logout_orb),
@@ -931,7 +897,6 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->logout_orb)
                 goto alloc_fail;
 
-        /* Login ORB DMA */
         scsi_id->login_orb =
                 pci_alloc_consistent(hi->host->pdev,
                                      sizeof(struct sbp2_login_orb),
@@ -939,51 +904,28 @@ static int sbp2_start_device(struct scsi_id_instance_data *scsi_id)
         if (!scsi_id->login_orb)
                 goto alloc_fail;
 
-        /*
-         * Create our command orb pool
-         */
         if (sbp2util_create_command_orb_pool(scsi_id)) {
                 SBP2_ERR("sbp2util_create_command_orb_pool failed!");
                 sbp2_remove_device(scsi_id);
                 return -ENOMEM;
         }
 
-        /* Schedule a timeout here. The reason is that we may be so close
-         * to a bus reset, that the device is not available for logins.
-         * This can happen when the bus reset is caused by the host
-         * connected to the sbp2 device being removed. That host would
-         * have a certain amount of time to relogin before the sbp2 device
-         * allows someone else to login instead. One second makes sense. */
+        /* Wait a second before trying to log in. Previously logged in
+         * initiators need a chance to reconnect. */
         if (msleep_interruptible(1000)) {
                 sbp2_remove_device(scsi_id);
                 return -EINTR;
         }
 
-        /*
-         * Login to the sbp-2 device
-         */
         if (sbp2_login_device(scsi_id)) {
-                /* Login failed, just remove the device. */
                 sbp2_remove_device(scsi_id);
                 return -EBUSY;
         }
 
-        /*
-         * Set max retries to something large on the device
-         */
         sbp2_set_busy_timeout(scsi_id);
-
-        /*
-         * Do a SBP-2 fetch agent reset
-         */
         sbp2_agent_reset(scsi_id, 1);
-
-        /*
-         * Get the max speed and packet size that we can use
-         */
         sbp2_max_speed_and_size(scsi_id);
 
-        /* Add this device to the scsi layer now */
         error = scsi_add_device(scsi_id->scsi_host, 0, scsi_id->ud->id, 0);
         if (error) {
                 SBP2_ERR("scsi_add_device failed");
@@ -1000,9 +942,6 @@ alloc_fail:
         return -ENOMEM;
 }
 
-/*
- * This function removes an sbp2 device from the sbp2scsi_host_info struct.
- */
 static void sbp2_remove_device(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi;
@@ -1012,7 +951,6 @@ static void sbp2_remove_device(struct scsi_id_instance_data *scsi_id)
 
         hi = scsi_id->hi;
 
-        /* This will remove our scsi device aswell */
         if (scsi_id->scsi_host) {
                 scsi_remove_host(scsi_id->scsi_host);
                 scsi_host_put(scsi_id->scsi_host);
@@ -1067,33 +1005,25 @@ static void sbp2_remove_device(struct scsi_id_instance_data *scsi_id)
 
 #ifdef CONFIG_IEEE1394_SBP2_PHYS_DMA
 /*
- * This function deals with physical dma write requests (for adapters that do not support
- * physical dma in hardware). Mostly just here for debugging...
+ * Deal with write requests on adapters which do not support physical DMA or
+ * have it switched off.
  */
 static int sbp2_handle_physdma_write(struct hpsb_host *host, int nodeid,
                                      int destid, quadlet_t *data, u64 addr,
                                      size_t length, u16 flags)
 {
-
-        /*
-         * Manually put the data in the right place.
-         */
         memcpy(bus_to_virt((u32) addr), data, length);
         return RCODE_COMPLETE;
 }
 
 /*
- * This function deals with physical dma read requests (for adapters that do not support
- * physical dma in hardware). Mostly just here for debugging...
+ * Deal with read requests on adapters which do not support physical DMA or
+ * have it switched off.
  */
 static int sbp2_handle_physdma_read(struct hpsb_host *host, int nodeid,
                                     quadlet_t *data, u64 addr, size_t length,
                                     u16 flags)
 {
-
-        /*
-         * Grab data from memory and send a read response.
-         */
         memcpy(data, bus_to_virt((u32) addr), length);
         return RCODE_COMPLETE;
 }
@@ -1103,10 +1033,6 @@ static int sbp2_handle_physdma_read(struct hpsb_host *host, int nodeid,
  * SBP-2 protocol related section
  **************************************/
 
-/*
- * This function queries the device for the maximum concurrent logins it
- * supports.
- */
 static int sbp2_query_logins(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
@@ -1172,10 +1098,6 @@ static int sbp2_query_logins(struct scsi_id_instance_data *scsi_id)
         return 0;
 }
 
-/*
- * This function is called in order to login to a particular SBP-2 device,
- * after a bus reset.
- */
 static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
@@ -1191,17 +1113,18 @@ static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
                 }
         }
 
-        /* Set-up login ORB, assume no password */
+        /* assume no password */
         scsi_id->login_orb->password_hi = 0;
         scsi_id->login_orb->password_lo = 0;
 
         scsi_id->login_orb->login_response_lo = scsi_id->login_response_dma;
         scsi_id->login_orb->login_response_hi = ORB_SET_NODE_ID(hi->host->node_id);
-
         scsi_id->login_orb->lun_misc = ORB_SET_FUNCTION(SBP2_LOGIN_REQUEST);
-        scsi_id->login_orb->lun_misc |= ORB_SET_RECONNECT(0);   /* One second reconnect time */
-        scsi_id->login_orb->lun_misc |= ORB_SET_EXCLUSIVE(exclusive_login);     /* Exclusive access to device */
-        scsi_id->login_orb->lun_misc |= ORB_SET_NOTIFY(1);      /* Notify us of login complete */
+
+        /* one second reconnect time */
+        scsi_id->login_orb->lun_misc |= ORB_SET_RECONNECT(0);
+        scsi_id->login_orb->lun_misc |= ORB_SET_EXCLUSIVE(exclusive_login);
+        scsi_id->login_orb->lun_misc |= ORB_SET_NOTIFY(1);
         scsi_id->login_orb->lun_misc |= ORB_SET_LUN(scsi_id->sbp2_lun);
 
         scsi_id->login_orb->passwd_resp_lengths =
@@ -1222,17 +1145,13 @@ static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
 
         hpsb_node_write(scsi_id->ne, scsi_id->sbp2_management_agent_addr, data, 8);
 
-        /*
-         * Wait for login status (up to 20 seconds)...
-         */
+        /* wait up to 20 seconds for login status */
         if (sbp2util_access_timeout(scsi_id, 20*HZ)) {
                 SBP2_ERR("Error logging into SBP-2 device - timed out");
                 return -EIO;
         }
 
-        /*
-         * Sanity. Make sure status returned matches login orb.
-         */
+        /* make sure that the returned status matches the login ORB */
         if (scsi_id->status_block.ORB_offset_lo != scsi_id->login_orb_dma) {
                 SBP2_ERR("Error logging into SBP-2 device - timed out");
                 return -EIO;
@@ -1243,15 +1162,7 @@ static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
                 return -EIO;
         }
 
-        /*
-         * Byte swap the login response, for use when reconnecting or
-         * logging out.
-         */
         sbp2util_cpu_to_be32_buffer(scsi_id->login_response, sizeof(struct sbp2_login_response));
-
-        /*
-         * Grab our command block agent address from the login response.
-         */
         scsi_id->sbp2_command_block_agent_addr =
                 ((u64)scsi_id->login_response->command_block_agent_hi) << 32;
         scsi_id->sbp2_command_block_agent_addr |= ((u64)scsi_id->login_response->command_block_agent_lo);
@@ -1261,19 +1172,12 @@ static int sbp2_login_device(struct scsi_id_instance_data *scsi_id)
         return 0;
 }
 
-/*
- * This function is called in order to logout from a particular SBP-2
- * device, usually called during driver unload.
- */
 static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
         quadlet_t data[2];
         int error;
 
-        /*
-         * Set-up logout ORB
-         */
         scsi_id->logout_orb->reserved1 = 0x0;
         scsi_id->logout_orb->reserved2 = 0x0;
         scsi_id->logout_orb->reserved3 = 0x0;
@@ -1281,8 +1185,6 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
 
         scsi_id->logout_orb->login_ID_misc = ORB_SET_FUNCTION(SBP2_LOGOUT_REQUEST);
         scsi_id->logout_orb->login_ID_misc |= ORB_SET_LOGIN_ID(scsi_id->login_response->length_login_ID);
-
-        /* Notify us when complete */
         scsi_id->logout_orb->login_ID_misc |= ORB_SET_NOTIFY(1);
 
         scsi_id->logout_orb->reserved5 = 0x0;
@@ -1291,14 +1193,8 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
         scsi_id->logout_orb->status_fifo_lo =
                 ORB_SET_STATUS_FIFO_LO(scsi_id->status_fifo_addr);
 
-        /*
-         * Byte swap ORB if necessary
-         */
         sbp2util_cpu_to_be32_buffer(scsi_id->logout_orb, sizeof(struct sbp2_logout_orb));
 
-        /*
-         * Ok, let's write to the target's management agent register
-         */
         data[0] = ORB_SET_NODE_ID(hi->host->node_id);
         data[1] = scsi_id->logout_orb_dma;
         sbp2util_cpu_to_be32_buffer(data, 8);
@@ -1308,7 +1204,7 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
         if (error)
                 return error;
 
-        /* Wait for device to logout...1 second. */
+        /* wait up to 1 second for the device to complete logout */
         if (sbp2util_access_timeout(scsi_id, HZ))
                 return -EIO;
 
@@ -1316,19 +1212,12 @@ static int sbp2_logout_device(struct scsi_id_instance_data *scsi_id)
         return 0;
 }
 
-/*
- * This function is called in order to reconnect to a particular SBP-2
- * device, after a bus reset.
- */
 static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
 {
         struct sbp2scsi_host_info *hi = scsi_id->hi;
         quadlet_t data[2];
         int error;
 
-        /*
-         * Set-up reconnect ORB
-         */
         scsi_id->reconnect_orb->reserved1 = 0x0;
         scsi_id->reconnect_orb->reserved2 = 0x0;
         scsi_id->reconnect_orb->reserved3 = 0x0;
@@ -1337,8 +1226,6 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
         scsi_id->reconnect_orb->login_ID_misc = ORB_SET_FUNCTION(SBP2_RECONNECT_REQUEST);
         scsi_id->reconnect_orb->login_ID_misc |=
                 ORB_SET_LOGIN_ID(scsi_id->login_response->length_login_ID);
-
-        /* Notify us when complete */
         scsi_id->reconnect_orb->login_ID_misc |= ORB_SET_NOTIFY(1);
 
         scsi_id->reconnect_orb->reserved5 = 0x0;
@@ -1347,9 +1234,6 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
         scsi_id->reconnect_orb->status_fifo_lo =
                 ORB_SET_STATUS_FIFO_LO(scsi_id->status_fifo_addr);
 
-        /*
-         * Byte swap ORB if necessary
-         */
         sbp2util_cpu_to_be32_buffer(scsi_id->reconnect_orb, sizeof(struct sbp2_reconnect_orb));
 
         data[0] = ORB_SET_NODE_ID(hi->host->node_id);
@@ -1361,17 +1245,13 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
         if (error)
                 return error;
 
-        /*
-         * Wait for reconnect status (up to 1 second)...
-         */
+        /* wait up to 1 second for reconnect status */
         if (sbp2util_access_timeout(scsi_id, HZ)) {
                 SBP2_ERR("Error reconnecting to SBP-2 device - timed out");
                 return -EIO;
         }
 
-        /*
-         * Sanity. Make sure status returned matches reconnect orb.
-         */
+        /* make sure that the returned status matches the reconnect ORB */
         if (scsi_id->status_block.ORB_offset_lo != scsi_id->reconnect_orb_dma) {
                 SBP2_ERR("Error reconnecting to SBP-2 device - timed out");
                 return -EIO;
@@ -1387,8 +1267,8 @@ static int sbp2_reconnect_device(struct scsi_id_instance_data *scsi_id)
 }
 
 /*
- * This function is called in order to set the busy timeout (number of
- * retries to attempt) on the sbp2 device.
+ * Set the target node's Single Phase Retry limit. Affects the target's retry
+ * behaviour if our node is too busy to accept requests.
  */
 static int sbp2_set_busy_timeout(struct scsi_id_instance_data *scsi_id)
 {
@@ -1400,11 +1280,6 @@ static int sbp2_set_busy_timeout(struct scsi_id_instance_data *scsi_id)
         return 0;
 }
 
-/*
- * This function is called to parse sbp2 device's config rom unit
- * directory. Used to determine things like sbp2 management agent offset,
- * and command set used (SCSI or RBC).
- */
 static void sbp2_parse_unit_directory(struct scsi_id_instance_data *scsi_id,
                                       struct unit_directory *ud)
 {
@@ -1422,12 +1297,10 @@ static void sbp2_parse_unit_directory(struct scsi_id_instance_data *scsi_id,
         unit_characteristics = 0x0;
         firmware_revision = 0x0;
 
-        /* Handle different fields in the unit directory, based on keys */
         csr1212_for_each_dir_entry(ud->ne->csr, kv, ud->ud_kv, dentry) {
                 switch (kv->key.id) {
                 case CSR1212_KV_ID_DEPENDENT_INFO:
                         if (kv->key.type == CSR1212_KV_TYPE_CSR_OFFSET)
-                                /* Save off the management agent address */
                                 management_agent_addr =
                                     CSR1212_REGISTER_SPACE_BASE +
                                     (kv->value.csr_offset << 2);
@@ -1438,29 +1311,27 @@ static void sbp2_parse_unit_directory(struct scsi_id_instance_data *scsi_id,
                         break;
 
                 case SBP2_COMMAND_SET_SPEC_ID_KEY:
-                        /* Command spec organization */
                         command_set_spec_id = kv->value.immediate;
                         break;
 
                 case SBP2_COMMAND_SET_KEY:
-                        /* Command set used by sbp2 device */
                         command_set = kv->value.immediate;
                         break;
 
                 case SBP2_UNIT_CHARACTERISTICS_KEY:
-                        /*
-                         * Unit characterisitcs (orb related stuff
-                         * that I'm not yet paying attention to)
-                         */
+                        /* FIXME: This is ignored so far.
+                         * See SBP-2 clause 7.4.8. */
                         unit_characteristics = kv->value.immediate;
                         break;
 
                 case SBP2_FIRMWARE_REVISION_KEY:
-                        /* Firmware revision */
                         firmware_revision = kv->value.immediate;
                         break;
 
                 default:
+                        /* FIXME: Check for SBP2_DEVICE_TYPE_AND_LUN_KEY.
+                         * Its "ordered" bit has consequences for command ORB
+                         * list handling. See SBP-2 clauses 4.6, 7.4.11, 10.2 */
                         break;
                 }
         }
@@ -1536,7 +1407,6 @@ static int sbp2_max_speed_and_size(struct scsi_id_instance_data *scsi_id)
         scsi_id->speed_code =
             hi->host->speed[NODEID_TO_NODE(scsi_id->ne->nodeid)];
 
-        /* Bump down our speed if the user requested it */
         if (scsi_id->speed_code > max_speed) {
                 scsi_id->speed_code = max_speed;
                 SBP2_INFO("Reducing speed to %s", hpsb_speedto_str[max_speed]);
@@ -1563,9 +1433,6 @@ static int sbp2_max_speed_and_size(struct scsi_id_instance_data *scsi_id)
         return 0;
 }
 
-/*
- * This function is called in order to perform a SBP-2 agent reset.
- */
 static int sbp2_agent_reset(struct scsi_id_instance_data *scsi_id, int wait)
 {
         quadlet_t data;
@@ -1590,9 +1457,7 @@ static int sbp2_agent_reset(struct scsi_id_instance_data *scsi_id, int wait)
                 return -EIO;
         }
 
-        /*
-         * Need to make sure orb pointer is written on next command
-         */
+        /* make sure that the ORB_POINTER is written on next command */
         spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
         scsi_id->last_orb = NULL;
         spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);
@@ -1612,7 +1477,7 @@ static void sbp2_prep_command_orb_sg(struct sbp2_command_orb *orb,
         orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
         orb->misc |= ORB_SET_DIRECTION(orb_direction);
 
-        /* Special case if only one element (and less than 64KB in size) */
+        /* special case if only one element (and less than 64KB in size) */
         if ((scsi_use_sg == 1) &&
             (sgpnt[0].length <= SBP2_MAX_SG_ELEMENT_LENGTH)) {
 
@@ -1642,10 +1507,8 @@ static void sbp2_prep_command_orb_sg(struct sbp2_command_orb *orb,
                 orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
                 orb->data_descriptor_lo = command->sge_dma;
 
-                /*
-                 * Loop through and fill out our sbp-2 page tables
-                 * (and split up anything too large)
-                 */
+                /* loop through and fill out our SBP-2 page tables
+                 * (and split up anything too large) */
                 for (i = 0, sg_count = 0 ; i < count; i++, sgpnt++) {
                         sg_len = sg_dma_len(sgpnt);
                         sg_addr = sg_dma_address(sgpnt);
@@ -1665,10 +1528,8 @@ static void sbp2_prep_command_orb_sg(struct sbp2_command_orb *orb,
                         }
                 }
 
-                /* Number of page table (s/g) elements */
                 orb->misc |= ORB_SET_DATA_SIZE(sg_count);
 
-                /* Byte swap page tables if necessary */
                 sbp2util_cpu_to_be32_buffer(sg_element,
                                             (sizeof(struct sbp2_unrestricted_page_table)) *
                                             sg_count);
@@ -1692,34 +1553,25 @@ static void sbp2_prep_command_orb_no_sg(struct sbp2_command_orb *orb,
         orb->data_descriptor_hi = ORB_SET_NODE_ID(hi->host->node_id);
         orb->misc |= ORB_SET_DIRECTION(orb_direction);
 
-        /*
-         * Handle case where we get a command w/o s/g enabled (but
-         * check for transfers larger than 64K)
-         */
+        /* handle case where we get a command w/o s/g enabled
+         * (but check for transfers larger than 64K) */
         if (scsi_request_bufflen <= SBP2_MAX_SG_ELEMENT_LENGTH) {
 
                 orb->data_descriptor_lo = command->cmd_dma;
                 orb->misc |= ORB_SET_DATA_SIZE(scsi_request_bufflen);
 
         } else {
+                /* The buffer is too large. Turn this into page tables. */
+
                 struct sbp2_unrestricted_page_table *sg_element =
                         &command->scatter_gather_element[0];
                 u32 sg_count, sg_len;
                 dma_addr_t sg_addr;
 
-                /*
-                 * Need to turn this into page tables, since the
-                 * buffer is too large.
-                 */
                 orb->data_descriptor_lo = command->sge_dma;
-
-                /* Use page tables (s/g) */
                 orb->misc |= ORB_SET_PAGE_TABLE_PRESENT(0x1);
 
-                /*
-                 * fill out our sbp-2 page tables (and split up
-                 * the large buffer)
-                 */
+                /* fill out our SBP-2 page tables; split up the large buffer */
                 sg_count = 0;
                 sg_len = scsi_request_bufflen;
                 sg_addr = command->cmd_dma;
@@ -1738,20 +1590,14 @@ static void sbp2_prep_command_orb_no_sg(struct sbp2_command_orb *orb,
                         sg_count++;
                 }
 
-                /* Number of page table (s/g) elements */
                 orb->misc |= ORB_SET_DATA_SIZE(sg_count);
 
-                /* Byte swap page tables if necessary */
                 sbp2util_cpu_to_be32_buffer(sg_element,
                                             (sizeof(struct sbp2_unrestricted_page_table)) *
                                              sg_count);
         }
 }
 
-/*
- * This function is called to create the actual command orb and s/g list
- * out of the scsi command itself.
- */
 static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
                                     struct sbp2_command_info *command,
                                     unchar *scsi_cmd,
@@ -1766,7 +1612,7 @@ static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
         u32 orb_direction;
 
         /*
-         * Set-up our command ORB..
+         * Set-up our command ORB.
          *
          * NOTE: We're doing unrestricted page tables (s/g), as this is
          * best performance (at least with the devices I have). This means
@@ -1777,7 +1623,7 @@ static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
         command_orb->next_ORB_lo = 0x0;
         command_orb->misc = ORB_SET_MAX_PAYLOAD(scsi_id->max_payload_size);
         command_orb->misc |= ORB_SET_SPEED(scsi_id->speed_code);
-        command_orb->misc |= ORB_SET_NOTIFY(1); /* Notify us when complete */
+        command_orb->misc |= ORB_SET_NOTIFY(1);
 
         if (dma_dir == DMA_NONE)
                 orb_direction = ORB_DIRECTION_NO_DATA_TRANSFER;
@@ -1790,7 +1636,7 @@ static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
                 orb_direction = ORB_DIRECTION_NO_DATA_TRANSFER;
         }
 
-        /* Set-up our pagetable stuff */
+        /* set up our page table stuff */
         if (orb_direction == ORB_DIRECTION_NO_DATA_TRANSFER) {
                 command_orb->data_descriptor_hi = 0x0;
                 command_orb->data_descriptor_lo = 0x0;
@@ -1803,17 +1649,12 @@ static void sbp2_create_command_orb(struct scsi_id_instance_data *scsi_id,
                                             orb_direction, scsi_request_bufflen,
                                             scsi_request_buffer, dma_dir);
 
-        /* Byte swap command ORB if necessary */
         sbp2util_cpu_to_be32_buffer(command_orb, sizeof(struct sbp2_command_orb));
 
-        /* Put our scsi command in the command ORB */
         memset(command_orb->cdb, 0, 12);
         memcpy(command_orb->cdb, scsi_cmd, COMMAND_SIZE(*scsi_cmd));
 }
 
-/*
- * This function is called in order to begin a regular SBP-2 command.
- */
 static void sbp2_link_orb_command(struct scsi_id_instance_data *scsi_id,
                                  struct sbp2_command_info *command)
 {
@@ -1832,9 +1673,8 @@ static void sbp2_link_orb_command(struct scsi_id_instance_data *scsi_id,
         pci_dma_sync_single_for_device(hi->host->pdev, command->sge_dma,
                                        sizeof(command->scatter_gather_element),
                                        PCI_DMA_BIDIRECTIONAL);
-        /*
-         * Check to see if there are any previous orbs to use
-         */
+
+        /* check to see if there are any previous orbs to use */
         spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
         last_orb = scsi_id->last_orb;
         last_orb_dma = scsi_id->last_orb_dma;
@@ -1892,9 +1732,6 @@ static void sbp2_link_orb_command(struct scsi_id_instance_data *scsi_id,
         }
 }
 
-/*
- * This function is called in order to begin a regular SBP-2 command.
- */
 static int sbp2_send_command(struct scsi_id_instance_data *scsi_id,
                              struct scsi_cmnd *SCpnt,
                              void (*done)(struct scsi_cmnd *))
@@ -1903,23 +1740,13 @@ static int sbp2_send_command(struct scsi_id_instance_data *scsi_id,
         unsigned int request_bufflen = SCpnt->request_bufflen;
         struct sbp2_command_info *command;
 
-        /*
-         * Allocate a command orb and s/g structure
-         */
         command = sbp2util_allocate_command_orb(scsi_id, SCpnt, done);
         if (!command)
                 return -EIO;
 
-        /*
-         * Now actually fill in the comamnd orb and sbp2 s/g list
-         */
         sbp2_create_command_orb(scsi_id, command, cmd, SCpnt->use_sg,
                                 request_bufflen, SCpnt->request_buffer,
                                 SCpnt->sc_data_direction);
-
-        /*
-         * Link up the orb, and ring the doorbell if needed
-         */
         sbp2_link_orb_command(scsi_id, command);
 
         return 0;
@@ -1930,9 +1757,7 @@ static int sbp2_send_command(struct scsi_id_instance_data *scsi_id,
  */
 static unsigned int sbp2_status_to_sense_data(unchar *sbp2_status, unchar *sense_data)
 {
-        /*
-         * Ok, it's pretty ugly...   ;-)
-         */
+        /* OK, it's pretty ugly... ;-) */
         sense_data[0] = 0x70;
         sense_data[1] = 0x0;
         sense_data[2] = sbp2_status[9];
@@ -1950,12 +1775,9 @@ static unsigned int sbp2_status_to_sense_data(unchar *sbp2_status, unchar *sense
         sense_data[14] = sbp2_status[20];
         sense_data[15] = sbp2_status[21];
 
-        return sbp2_status[8] & 0x3f;   /* return scsi status */
+        return sbp2_status[8] & 0x3f;
 }
 
-/*
- * This function deals with status writes from the SBP-2 device
- */
 static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                                     int destid, quadlet_t *data, u64 addr,
                                     size_t length, u16 fl)
@@ -1981,10 +1803,8 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                 SBP2_ERR("host info is NULL - this is bad!");
                 return RCODE_ADDRESS_ERROR;
         }
-        /*
-         * Find our scsi_id structure by looking at the status fifo address
-         * written to by the sbp2 device.
-         */
+
+        /* Find the unit which wrote the status. */
         list_for_each_entry(scsi_id_tmp, &hi->scsi_ids, scsi_list) {
                 if (scsi_id_tmp->ne->nodeid == nodeid &&
                     scsi_id_tmp->status_fifo_addr == addr) {
@@ -1997,20 +1817,16 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                 return RCODE_ADDRESS_ERROR;
         }
 
-        /*
-         * Put response into scsi_id status fifo buffer. The first two bytes
+        /* Put response into scsi_id status fifo buffer. The first two bytes
          * come in big endian bit order. Often the target writes only a
          * truncated status block, minimally the first two quadlets. The rest
-         * is implied to be zeros.
-         */
+         * is implied to be zeros. */
         sb = &scsi_id->status_block;
         memset(sb->command_set_dependent, 0, sizeof(sb->command_set_dependent));
         memcpy(sb, data, length);
         sbp2util_be32_to_cpu_buffer(sb, 8);
 
-        /*
-         * Ignore unsolicited status. Handle command ORB status.
-         */
+        /* Ignore unsolicited status. Handle command ORB status. */
         if (unlikely(STATUS_GET_SRC(sb->ORB_offset_hi_misc) == 2))
                 command = NULL;
         else
@@ -2023,10 +1839,7 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                 pci_dma_sync_single_for_cpu(hi->host->pdev, command->sge_dma,
                                             sizeof(command->scatter_gather_element),
                                             PCI_DMA_BIDIRECTIONAL);
-                /*
-                 * Matched status with command, now grab scsi command pointers
-                 * and check status.
-                 */
+                /* Grab SCSI command pointers and check status. */
                 /*
                  * FIXME: If the src field in the status is 1, the ORB DMA must
                  * not be reused until status for a subsequent ORB is received.
@@ -2048,37 +1861,28 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
                                         SBP2_SCSI_STATUS_BUSY :
                                         SBP2_SCSI_STATUS_COMMAND_TERMINATED;
                         }
-                        /*
-                         * See if the target stored any scsi status information.
-                         */
+
                         if (STATUS_GET_LEN(h) > 1)
                                 scsi_status = sbp2_status_to_sense_data(
                                         (unchar *)sb, SCpnt->sense_buffer);
-                        /*
-                         * Check to see if the dead bit is set. If so, we'll
-                         * have to initiate a fetch agent reset.
-                         */
+
                         if (STATUS_TEST_DEAD(h))
                                 sbp2_agent_reset(scsi_id, 0);
                 }
 
-                /*
-                 * Check here to see if there are no commands in-use. If there
+                /* Check here to see if there are no commands in-use. If there
                  * are none, we know that the fetch agent left the active state
                  * _and_ that we did not reactivate it yet. Therefore clear
                  * last_orb so that next time we write directly to the
                  * ORB_POINTER register. That way the fetch agent does not need
-                 * to refetch the next_ORB.
-                 */
+                 * to refetch the next_ORB. */
                 spin_lock_irqsave(&scsi_id->sbp2_command_orb_lock, flags);
                 if (list_empty(&scsi_id->sbp2_command_orb_inuse))
                         scsi_id->last_orb = NULL;
                 spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);
 
         } else {
-                /*
-                 * It's probably a login/logout/reconnect status.
-                 */
+                /* It's probably status after a management request. */
                 if ((sb->ORB_offset_lo == scsi_id->reconnect_orb_dma) ||
                     (sb->ORB_offset_lo == scsi_id->login_orb_dma) ||
                     (sb->ORB_offset_lo == scsi_id->query_logins_orb_dma) ||
@@ -2098,10 +1902,6 @@ static int sbp2_handle_status_write(struct hpsb_host *host, int nodeid,
  * SCSI interface related section
  **************************************/
 
-/*
- * This routine is the main request entry routine for doing I/O. It is
- * called from the scsi stack directly.
- */
 static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt,
                                  void (*done)(struct scsi_cmnd *))
 {
@@ -2120,17 +1920,13 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt,
                 goto done;
         }
 
-        /*
-         * Until we handle multiple luns, just return selection time-out
-         * to any IO directed at non-zero LUNs
-         */
+        /* Multiple units are currently represented to the SCSI core as separate
+         * targets, not as one target with multiple LUs. Therefore return
+         * selection time-out to any IO directed at non-zero LUNs. */
         if (SCpnt->device->lun)
                 goto done;
 
-        /*
-         * Check for request sense command, and handle it here
-         * (autorequest sense)
-         */
+        /* handle the request sense command here (auto-request sense) */
         if (SCpnt->cmnd[0] == REQUEST_SENSE) {
                 memcpy(SCpnt->request_buffer, SCpnt->sense_buffer, SCpnt->request_bufflen);
                 memset(SCpnt->sense_buffer, 0, sizeof(SCpnt->sense_buffer));
@@ -2138,28 +1934,20 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt,
                 return 0;
         }
 
-        /*
-         * Check to see if we are in the middle of a bus reset.
-         */
         if (!hpsb_node_entry_valid(scsi_id->ne)) {
                 SBP2_ERR("Bus reset in progress - rejecting command");
                 result = DID_BUS_BUSY << 16;
                 goto done;
         }
 
-        /*
-         * Bidirectional commands are not yet implemented,
-         * and unknown transfer direction not handled.
-         */
+        /* Bidirectional commands are not yet implemented,
+         * and unknown transfer direction not handled. */
         if (SCpnt->sc_data_direction == DMA_BIDIRECTIONAL) {
                 SBP2_ERR("Cannot handle DMA_BIDIRECTIONAL - rejecting command");
                 result = DID_ERROR << 16;
                 goto done;
         }
 
-        /*
-         * Try and send our SCSI command
-         */
         if (sbp2_send_command(scsi_id, SCpnt, done)) {
                 SBP2_ERR("Error sending SCSI command");
                 sbp2scsi_complete_command(scsi_id, SBP2_SCSI_STATUS_SELECTION_TIMEOUT,
@@ -2173,10 +1961,6 @@ done:
         return 0;
 }
 
-/*
- * This function is called in order to complete all outstanding SBP-2
- * commands (in case of resets, etc.).
- */
 static void sbp2scsi_complete_all_commands(struct scsi_id_instance_data *scsi_id,
                                            u32 status)
 {
@@ -2207,25 +1991,17 @@ static void sbp2scsi_complete_all_commands(struct scsi_id_instance_data *scsi_id
 }
 
 /*
- * This function is called in order to complete a regular SBP-2 command.
- *
- * This can be called in interrupt context.
+ * Complete a regular SCSI command. Can be called in atomic context.
  */
 static void sbp2scsi_complete_command(struct scsi_id_instance_data *scsi_id,
                                       u32 scsi_status, struct scsi_cmnd *SCpnt,
                                       void (*done)(struct scsi_cmnd *))
 {
-        /*
-         * Sanity
-         */
         if (!SCpnt) {
                 SBP2_ERR("SCpnt is NULL");
                 return;
         }
 
-        /*
-         * Switch on scsi status
-         */
         switch (scsi_status) {
         case SBP2_SCSI_STATUS_GOOD:
                 SCpnt->result = DID_OK << 16;
@@ -2259,19 +2035,15 @@ static void sbp2scsi_complete_command(struct scsi_id_instance_data *scsi_id,
                 SCpnt->result = DID_ERROR << 16;
         }
 
-        /*
-         * If a bus reset is in progress and there was an error, complete
-         * the command as busy so that it will get retried.
-         */
+        /* If a bus reset is in progress and there was an error, complete
+         * the command as busy so that it will get retried. */
         if (!hpsb_node_entry_valid(scsi_id->ne)
             && (scsi_status != SBP2_SCSI_STATUS_GOOD)) {
                 SBP2_ERR("Completing command with busy (bus reset)");
                 SCpnt->result = DID_BUS_BUSY << 16;
         }
 
-        /*
-         * Tell scsi stack that we're done with this command
-         */
+        /* Tell the SCSI stack that we're done with this command. */
         done(SCpnt);
 }
 
@@ -2311,8 +2083,8 @@ static void sbp2scsi_slave_destroy(struct scsi_device *sdev)
 }
 
 /*
- * Called by scsi stack when something has really gone wrong.  Usually
- * called when a command has timed-out for some reason.
+ * Called by scsi stack when something has really gone wrong.
+ * Usually called when a command has timed-out for some reason.
  */
 static int sbp2scsi_abort(struct scsi_cmnd *SCpnt)
 {
@@ -2401,7 +2173,6 @@ static int sbp2_module_init(void)
 {
         int ret;
 
-        /* Module load debug option to force one command at a time (serializing I/O) */
         if (serialize_io) {
                 scsi_driver_template.can_queue = 1;
                 scsi_driver_template.cmd_per_lun = 1;
@@ -2412,16 +2183,13 @@ static int sbp2_module_init(void)
                 max_sectors = 128 * 1024 / 512;
         scsi_driver_template.max_sectors = max_sectors;
 
-        /* Register our high level driver with 1394 stack */
         hpsb_register_highlevel(&sbp2_highlevel);
-
         ret = hpsb_register_protocol(&sbp2_driver);
         if (ret) {
                 SBP2_ERR("Failed to register protocol");
                 hpsb_unregister_highlevel(&sbp2_highlevel);
                 return ret;
         }
-
         return 0;
 }