isci: cleanup tag macros

A tag is a 16 bit number where the upper four bits is a sequence number
and the remainder is the task context index (tci).  Sanitize the macro
names and shave 256-bytes out of scic_sds_controller by reducing the size of
io_request_sequence.

scic_sds_io_tag_construct --> ISCI_TAG
scic_sds_io_tag_get_sequence --> ISCI_TAG_SEQ
scic_sds_io_tag_get_index() --> ISCI_TAG_TCI
scic_sds_io_sequence_increment() [delete / open code]

Signed-off-by: Dan Williams <dan.j.williams@intel.com>

5 files changed, 52 insertions, 114 deletions

diff --git a/drivers/scsi/isci/host.c b/drivers/scsi/isci/host.c
index 343655bd1a6a..3c7042b8bc0e 100644
--- a/drivers/scsi/isci/host.c
+++ b/drivers/scsi/isci/host.c
@@ -284,23 +284,16 @@ static void scic_sds_controller_task_completion(struct scic_sds_controller *scic
                                                 u32 completion_entry)
 {
         u32 index;
-        struct scic_sds_request *io_request;
+        struct scic_sds_request *sci_req;
 
         index = SCU_GET_COMPLETION_INDEX(completion_entry);
-        io_request = scic->io_request_table[index];
+        sci_req = scic->io_request_table[index];
 
         /* Make sure that we really want to process this IO request */
-        if (
-                (io_request != NULL)
-                && (io_request->io_tag != SCI_CONTROLLER_INVALID_IO_TAG)
-                && (
-                        scic_sds_io_tag_get_sequence(io_request->io_tag)
-                        == scic->io_request_sequence[index]
-                        )
-                ) {
+        if (sci_req && sci_req->io_tag != SCI_CONTROLLER_INVALID_IO_TAG &&
+            ISCI_TAG_SEQ(sci_req->io_tag) == scic->io_request_sequence[index])
                 /* Yep this is a valid io request pass it along to the io request handler */
-                scic_sds_io_request_tc_completion(io_request, completion_entry);
-        }
+                scic_sds_io_request_tc_completion(sci_req, completion_entry);
 }
 
 static void scic_sds_controller_sdma_completion(struct scic_sds_controller *scic,
@@ -2682,37 +2675,28 @@ void scic_sds_controller_copy_task_context(
         sci_req->task_context_buffer = task_context_buffer;
 }
 
-/**
- * This method returns the task context buffer for the given io tag.
- * @scic:
- * @io_tag:
- *
- * struct scu_task_context*
- */
-struct scu_task_context *scic_sds_controller_get_task_context_buffer(
-        struct scic_sds_controller *scic,
-        u16 io_tag
-        ) {
-        u16 task_index = scic_sds_io_tag_get_index(io_tag);
+struct scu_task_context *scic_sds_controller_get_task_context_buffer(struct scic_sds_controller *scic,
+                                                                     u16 io_tag)
+{
+        u16 tci = ISCI_TAG_TCI(io_tag);
 
-        if (task_index < scic->task_context_entries) {
-                return &scic->task_context_table[task_index];
+        if (tci < scic->task_context_entries) {
+                return &scic->task_context_table[tci];
         }
 
         return NULL;
 }
 
-struct scic_sds_request *scic_request_by_tag(struct scic_sds_controller *scic,
-                                             u16 io_tag)
+struct scic_sds_request *scic_request_by_tag(struct scic_sds_controller *scic, u16 io_tag)
 {
         u16 task_index;
         u16 task_sequence;
 
-        task_index = scic_sds_io_tag_get_index(io_tag);
+        task_index = ISCI_TAG_TCI(io_tag);
 
-        if (task_index  < scic->task_context_entries) {
+        if (task_index < scic->task_context_entries) {
                 if (scic->io_request_table[task_index] != NULL) {
-                        task_sequence = scic_sds_io_tag_get_sequence(io_tag);
+                        task_sequence = ISCI_TAG_SEQ(io_tag);
 
                         if (task_sequence == scic->io_request_sequence[task_index]) {
                                 return scic->io_request_table[task_index];
@@ -2875,11 +2859,10 @@ void scic_sds_controller_release_frame(
  * successfully started the IO request. SCI_SUCCESS if the IO request was
  * successfully started. Determine the failure situations and return values.
  */
-enum sci_status scic_controller_start_io(
-        struct scic_sds_controller *scic,
-        struct scic_sds_remote_device *rdev,
-        struct scic_sds_request *req,
-        u16 io_tag)
+enum sci_status scic_controller_start_io(struct scic_sds_controller *scic,
+                                         struct scic_sds_remote_device *rdev,
+                                         struct scic_sds_request *req,
+                                         u16 io_tag)
 {
         enum sci_status status;
 
@@ -2892,7 +2875,7 @@ enum sci_status scic_controller_start_io(
         if (status != SCI_SUCCESS)
                 return status;
 
-        scic->io_request_table[scic_sds_io_tag_get_index(req->io_tag)] = req;
+        scic->io_request_table[ISCI_TAG_TCI(req->io_tag)] = req;
         scic_sds_controller_post_request(scic, scic_sds_request_get_post_context(req));
         return SCI_SUCCESS;
 }
@@ -2979,7 +2962,7 @@ enum sci_status scic_controller_complete_io(
                 if (status != SCI_SUCCESS)
                         return status;
 
-                index = scic_sds_io_tag_get_index(request->io_tag);
+                index = ISCI_TAG_TCI(request->io_tag);
                 scic->io_request_table[index] = NULL;
                 return SCI_SUCCESS;
         default:
@@ -2998,7 +2981,7 @@ enum sci_status scic_controller_continue_io(struct scic_sds_request *sci_req)
                 return SCI_FAILURE_INVALID_STATE;
         }
 
-        scic->io_request_table[scic_sds_io_tag_get_index(sci_req->io_tag)] = sci_req;
+        scic->io_request_table[ISCI_TAG_TCI(sci_req->io_tag)] = sci_req;
         scic_sds_controller_post_request(scic, scic_sds_request_get_post_context(sci_req));
         return SCI_SUCCESS;
 }
@@ -3050,7 +3033,7 @@ enum sci_task_status scic_controller_start_task(
         status = scic_sds_remote_device_start_task(scic, rdev, req);
         switch (status) {
         case SCI_FAILURE_RESET_DEVICE_PARTIAL_SUCCESS:
-                scic->io_request_table[scic_sds_io_tag_get_index(req->io_tag)] = req;
+                scic->io_request_table[ISCI_TAG_TCI(req->io_tag)] = req;
 
                 /*
                  * We will let framework know this task request started successfully,
@@ -3059,7 +3042,7 @@ enum sci_task_status scic_controller_start_task(
                  */
                 return SCI_SUCCESS;
         case SCI_SUCCESS:
-                scic->io_request_table[scic_sds_io_tag_get_index(req->io_tag)] = req;
+                scic->io_request_table[ISCI_TAG_TCI(req->io_tag)] = req;
 
                 scic_sds_controller_post_request(scic,
                         scic_sds_request_get_post_context(req));
@@ -3096,14 +3079,12 @@ enum sci_task_status scic_controller_start_task(
 u16 scic_controller_allocate_io_tag(struct scic_sds_controller *scic)
 {
         struct isci_host *ihost = scic_to_ihost(scic);
-        u16 tci;
-        u16 seq;
 
         if (isci_tci_space(ihost)) {
-                tci = isci_tci_alloc(ihost);
-                seq = scic->io_request_sequence[tci];
+                u16 tci = isci_tci_alloc(ihost);
+                u8 seq = scic->io_request_sequence[tci];
 
-                return scic_sds_io_tag_construct(seq, tci);
+                return ISCI_TAG(seq, tci);
         }
 
         return SCI_CONTROLLER_INVALID_IO_TAG;
@@ -3138,22 +3119,17 @@ enum sci_status scic_controller_free_io_tag(struct scic_sds_controller *scic,
                                             u16 io_tag)
 {
         struct isci_host *ihost = scic_to_ihost(scic);
-        u16 sequence;
-        u16 index;
-
-        BUG_ON(io_tag == SCI_CONTROLLER_INVALID_IO_TAG);
-
-        sequence = scic_sds_io_tag_get_sequence(io_tag);
-        index    = scic_sds_io_tag_get_index(io_tag);
+        u16 tci = ISCI_TAG_TCI(io_tag);
+        u16 seq = ISCI_TAG_SEQ(io_tag);
 
         /* prevent tail from passing head */
         if (isci_tci_active(ihost) == 0)
                 return SCI_FAILURE_INVALID_IO_TAG;
 
-        if (sequence == scic->io_request_sequence[index]) {
-                scic_sds_io_sequence_increment(scic->io_request_sequence[index]);
+        if (seq == scic->io_request_sequence[tci]) {
+                scic->io_request_sequence[tci] = (seq+1) & (SCI_MAX_SEQ-1);
 
-                isci_tci_free(ihost, index);
+                isci_tci_free(ihost, ISCI_TAG_TCI(io_tag));
 
                 return SCI_SUCCESS;
         }
diff --git a/drivers/scsi/isci/host.h b/drivers/scsi/isci/host.h
index c61a9fa130b7..7d17ab80f1a9 100644
--- a/drivers/scsi/isci/host.h
+++ b/drivers/scsi/isci/host.h
@@ -184,13 +184,8 @@ struct scic_sds_controller {
          */
         struct scic_power_control power_control;
 
-        /**
-         * This field is the array of sequence values for the IO Tag fields.  Even
-         * though only 4 bits of the field is used for the sequence the sequence is 16
-         * bits in size so the sequence can be bitwise or'd with the TCi to build the
-         * IO Tag value.
-         */
-        u16 io_request_sequence[SCI_MAX_IO_REQUESTS];
+        /* sequence number per tci */
+        u8 io_request_sequence[SCI_MAX_IO_REQUESTS];
 
         /**
          * This field in the array of sequence values for the RNi.  These are used
@@ -552,40 +547,12 @@ static inline struct isci_host *scic_to_ihost(struct scic_sds_controller *scic)
  */
 #define scic_sds_controller_get_protocol_engine_group(controller) 0
 
-/**
- * scic_sds_io_tag_construct() -
- *
- * This macro constructs an IO tag from the sequence and index values.
- */
-#define scic_sds_io_tag_construct(sequence, task_index) \
-        ((sequence) << 12 | (task_index))
-
-/**
- * scic_sds_io_tag_get_sequence() -
- *
- * This macro returns the IO sequence from the IO tag value.
- */
-#define scic_sds_io_tag_get_sequence(io_tag) \
-        (((io_tag) & 0xF000) >> 12)
-
-/**
- * scic_sds_io_tag_get_index() -
- *
- * This macro returns the TCi from the io tag value
- */
-#define scic_sds_io_tag_get_index(io_tag) \
-        ((io_tag) & 0x0FFF)
+/* see scic_controller_io_tag_allocate|free for how seq and tci are built */
+#define ISCI_TAG(seq, tci) (((u16) (seq)) << 12 | tci)
 
-/**
- * scic_sds_io_sequence_increment() -
- *
- * This is a helper macro to increment the io sequence count. We may find in
- * the future that it will be faster to store the sequence count in such a way
- * as we dont perform the shift operation to build io tag values so therefore
- * need a way to incrment them correctly
- */
-#define scic_sds_io_sequence_increment(value) \
-        ((value) = (((value) + 1) & 0x000F))
+/* these are returned by the hardware, so sanitize them */
+#define ISCI_TAG_SEQ(tag) (((tag) >> 12) & (SCI_MAX_SEQ-1))
+#define ISCI_TAG_TCI(tag) ((tag) & (SCI_MAX_IO_REQUESTS-1))
 
 /* expander attached sata devices require 3 rnc slots */
 static inline int scic_sds_remote_device_node_count(struct scic_sds_remote_device *sci_dev)
diff --git a/drivers/scsi/isci/isci.h b/drivers/scsi/isci/isci.h
index 84ba533ca51e..81bade421b96 100644
--- a/drivers/scsi/isci/isci.h
+++ b/drivers/scsi/isci/isci.h
@@ -83,6 +83,7 @@ enum sci_controller_mode {
 #define SCI_MAX_SMP_PHYS  (384) /* not silicon constrained */
 #define SCI_MAX_REMOTE_DEVICES (256UL)
 #define SCI_MAX_IO_REQUESTS (256UL)
+#define SCI_MAX_SEQ (16)
 #define SCI_MAX_MSIX_MESSAGES  (2)
 #define SCI_MAX_SCATTER_GATHER_ELEMENTS 130 /* not silicon constrained */
 #define SCI_MAX_CONTROLLERS 2
@@ -113,6 +114,7 @@ static inline void check_sizes(void)
         BUILD_BUG_ON_NOT_POWER_OF_2(SCU_MAX_COMPLETION_QUEUE_ENTRIES);
         BUILD_BUG_ON(SCU_MAX_UNSOLICITED_FRAMES > SCU_ABSOLUTE_MAX_UNSOLICITED_FRAMES);
         BUILD_BUG_ON_NOT_POWER_OF_2(SCI_MAX_IO_REQUESTS);
+        BUILD_BUG_ON_NOT_POWER_OF_2(SCI_MAX_SEQ);
 }
 
 /**
diff --git a/drivers/scsi/isci/port.c b/drivers/scsi/isci/port.c
index e540281ebd49..fb66e30da075 100644
--- a/drivers/scsi/isci/port.c
+++ b/drivers/scsi/isci/port.c
@@ -689,23 +689,16 @@ static void scic_sds_port_construct_dummy_rnc(struct scic_sds_port *sci_port, u1
         rnc->ssp.arbitration_wait_time = 0;
 }
 
-/**
- * scic_sds_port_construct_dummy_task() - create dummy task for si workaround
- * @sci_port The logical port on which we need to create the
- *            remote node context.
- *            context.
- * @tci The remote node index for this remote node context.
- *
- * This routine will construct a dummy task context data structure.  This
+/*
+ * construct a dummy task context data structure.  This
  * structure will be posted to the hardwre to work around a scheduler error
  * in the hardware.
- *
  */
-static void scic_sds_port_construct_dummy_task(struct scic_sds_port *sci_port, u16 tci)
+static void scic_sds_port_construct_dummy_task(struct scic_sds_port *sci_port, u16 tag)
 {
         struct scu_task_context *task_context;
 
-        task_context = scic_sds_controller_get_task_context_buffer(sci_port->owning_controller, tci);
+        task_context = scic_sds_controller_get_task_context_buffer(sci_port->owning_controller, tag);
 
         memset(task_context, 0, sizeof(struct scu_task_context));
 
@@ -716,7 +709,7 @@ static void scic_sds_port_construct_dummy_task(struct scic_sds_port *sci_port, u
         task_context->protocol_engine_index = 0;
         task_context->logical_port_index = sci_port->physical_port_index;
         task_context->protocol_type = SCU_TASK_CONTEXT_PROTOCOL_SSP;
-        task_context->task_index = scic_sds_io_tag_get_index(tci);
+        task_context->task_index = ISCI_TAG_TCI(tag);
         task_context->valid = SCU_TASK_CONTEXT_VALID;
         task_context->context_type = SCU_TASK_CONTEXT_TYPE;
 
diff --git a/drivers/scsi/isci/request.c b/drivers/scsi/isci/request.c
index 433565c2b343..9d7531ad9a74 100644
--- a/drivers/scsi/isci/request.c
+++ b/drivers/scsi/isci/request.c
@@ -258,7 +258,7 @@ static void scu_ssp_reqeust_construct_task_context(
                           SCU_CONTEXT_COMMAND_PROTOCOL_ENGINE_GROUP_SHIFT) |
                          (scic_sds_port_get_index(target_port) <<
                           SCU_CONTEXT_COMMAND_LOGICAL_PORT_SHIFT) |
-                         scic_sds_io_tag_get_index(sds_request->io_tag));
+                          ISCI_TAG_TCI(sds_request->io_tag));
         } else {
                 /*
                  * Build the task context now since we have already read
@@ -433,7 +433,7 @@ static void scu_sata_reqeust_construct_task_context(
                           SCU_CONTEXT_COMMAND_PROTOCOL_ENGINE_GROUP_SHIFT) |
                          (scic_sds_port_get_index(target_port) <<
                           SCU_CONTEXT_COMMAND_LOGICAL_PORT_SHIFT) |
-                         scic_sds_io_tag_get_index(sci_req->io_tag));
+                          ISCI_TAG_TCI(sci_req->io_tag));
         } else {
                 /*
                  * Build the task context now since we have already read
@@ -741,7 +741,7 @@ static u32 sci_req_tx_bytes(struct scic_sds_request *sci_req)
                  */
                 ret_val = readl(scu_reg_base +
                                 (SCU_TASK_CONTEXT_SRAM + offsetof(struct scu_task_context, type.ssp.data_offset)) +
-                                ((sizeof(struct scu_task_context)) * scic_sds_io_tag_get_index(sci_req->io_tag)));
+                                ((sizeof(struct scu_task_context)) * ISCI_TAG_TCI(sci_req->io_tag)));
         }
 
         return ret_val;
@@ -777,7 +777,7 @@ enum sci_status scic_sds_request_start(struct scic_sds_request *sci_req)
         if (sci_req->io_tag != SCI_CONTROLLER_INVALID_IO_TAG) {
                 task_context = sci_req->task_context_buffer;
 
-                task_context->task_index = scic_sds_io_tag_get_index(sci_req->io_tag);
+                task_context->task_index = ISCI_TAG_TCI(sci_req->io_tag);
 
                 switch (task_context->protocol_type) {
                 case SCU_TASK_CONTEXT_PROTOCOL_SMP:
@@ -811,7 +811,7 @@ enum sci_status scic_sds_request_start(struct scic_sds_request *sci_req)
                         scic_sds_controller_copy_task_context(scic, sci_req);
 
                 /* Add to the post_context the io tag value */
-                sci_req->post_context |= scic_sds_io_tag_get_index(sci_req->io_tag);
+                sci_req->post_context |= ISCI_TAG_TCI(sci_req->io_tag);
 
                 /* Everything is good go ahead and change state */
                 sci_change_state(&sci_req->sm, SCI_REQ_STARTED);
@@ -3325,7 +3325,7 @@ scu_smp_request_construct_task_context(struct scic_sds_request *sci_req,
                           SCU_CONTEXT_COMMAND_PROTOCOL_ENGINE_GROUP_SHIFT) |
                          (scic_sds_port_get_index(sci_port) <<
                           SCU_CONTEXT_COMMAND_LOGICAL_PORT_SHIFT) |
-                         scic_sds_io_tag_get_index(sci_req->io_tag));
+                          ISCI_TAG_TCI(sci_req->io_tag));
         } else {
                 /*
                  * Build the task context now since we have already read