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isci: unify can_queue tracking on the tci_pool, uplevel tag assignment
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The tci_pool tracks our outstanding command slots which are also the 'index'
portion of our tags.  Grabbing the tag early in ->lldd_execute_task let's us
drop the isci_host_can_queue() and ->was_tag_assigned_by_user infrastructure.
->was_tag_assigned_by_user required the task context to be duplicated in
request-local buffer.  With the tci established early we can build the
task_context directly into its final location and skip a memcpy.

With the task context buffer at a known address at request construction we
have the opportunity/obligation to also fix sgl handling.  This rework feels
like it belongs in another patch but the sgl handling and task_context are too
intertwined.
1/ fix the 'ab' pair embedded in the task context to point to the 'cd' pair in
   the task context (previously we were prematurely linking to the staging
   buffer).
2/ fix the broken iteration of pio sgls that assumes all sgls are relative to
   the request, and does a dangerous looking reverse lookup of physical
   address to virtual address.

Signed-off-by: Dan Williams <[email protected]>
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@djbw
djbw committed Jul 3, 2011
1 parent 9274f45 commit 312e0c2
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Showing 7 changed files with 303 additions and 687 deletions.
265 changes: 64 additions & 201 deletions drivers/scsi/isci/host.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1018,33 +1018,11 @@ static void phy_startup_timeout(unsigned long data)
spin_unlock_irqrestore(&ihost->scic_lock, flags);
}

static void isci_tci_free(struct isci_host *ihost, u16 tci)
{
u16 tail = ihost->tci_tail & (SCI_MAX_IO_REQUESTS-1);

ihost->tci_pool[tail] = tci;
ihost->tci_tail = tail + 1;
}

static u16 isci_tci_alloc(struct isci_host *ihost)
{
u16 head = ihost->tci_head & (SCI_MAX_IO_REQUESTS-1);
u16 tci = ihost->tci_pool[head];

ihost->tci_head = head + 1;
return tci;
}

static u16 isci_tci_active(struct isci_host *ihost)
{
return CIRC_CNT(ihost->tci_head, ihost->tci_tail, SCI_MAX_IO_REQUESTS);
}

static u16 isci_tci_space(struct isci_host *ihost)
{
return CIRC_SPACE(ihost->tci_head, ihost->tci_tail, SCI_MAX_IO_REQUESTS);
}

static enum sci_status scic_controller_start(struct scic_sds_controller *scic,
u32 timeout)
{
Expand Down Expand Up @@ -1205,6 +1183,11 @@ static void isci_host_completion_routine(unsigned long data)
task->task_done(task);
}
}

spin_lock_irq(&isci_host->scic_lock);
isci_free_tag(isci_host, request->sci.io_tag);
spin_unlock_irq(&isci_host->scic_lock);

/* Free the request object. */
isci_request_free(isci_host, request);
}
Expand Down Expand Up @@ -1242,6 +1225,7 @@ static void isci_host_completion_routine(unsigned long data)
* of pending requests.
*/
list_del_init(&request->dev_node);
isci_free_tag(isci_host, request->sci.io_tag);
spin_unlock_irq(&isci_host->scic_lock);

/* Free the request object. */
Expand Down Expand Up @@ -2375,6 +2359,7 @@ static int scic_controller_mem_init(struct scic_sds_controller *scic)
if (!scic->task_context_table)
return -ENOMEM;

scic->task_context_dma = dma;
writel(lower_32_bits(dma), &scic->smu_registers->host_task_table_lower);
writel(upper_32_bits(dma), &scic->smu_registers->host_task_table_upper);

Expand Down Expand Up @@ -2409,11 +2394,9 @@ int isci_host_init(struct isci_host *isci_host)

spin_lock_init(&isci_host->state_lock);
spin_lock_init(&isci_host->scic_lock);
spin_lock_init(&isci_host->queue_lock);
init_waitqueue_head(&isci_host->eventq);

isci_host_change_state(isci_host, isci_starting);
isci_host->can_queue = ISCI_CAN_QUEUE_VAL;

status = scic_controller_construct(&isci_host->sci, scu_base(isci_host),
smu_base(isci_host));
Expand Down Expand Up @@ -2611,51 +2594,6 @@ void scic_sds_controller_post_request(
writel(request, &scic->smu_registers->post_context_port);
}

/**
* This method will copy the soft copy of the task context into the physical
* memory accessible by the controller.
* @scic: This parameter specifies the controller for which to copy
* the task context.
* @sci_req: This parameter specifies the request for which the task
* context is being copied.
*
* After this call is made the SCIC_SDS_IO_REQUEST object will always point to
* the physical memory version of the task context. Thus, all subsequent
* updates to the task context are performed in the TC table (i.e. DMAable
* memory). none
*/
void scic_sds_controller_copy_task_context(
struct scic_sds_controller *scic,
struct scic_sds_request *sci_req)
{
struct scu_task_context *task_context_buffer;

task_context_buffer = scic_sds_controller_get_task_context_buffer(
scic, sci_req->io_tag);

memcpy(task_context_buffer,
sci_req->task_context_buffer,
offsetof(struct scu_task_context, sgl_snapshot_ac));

/*
* Now that the soft copy of the TC has been copied into the TC
* table accessible by the silicon. Thus, any further changes to
* the TC (e.g. TC termination) occur in the appropriate location. */
sci_req->task_context_buffer = task_context_buffer;
}

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 (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)
{
u16 task_index;
Expand Down Expand Up @@ -2801,6 +2739,60 @@ void scic_sds_controller_release_frame(
&scic->scu_registers->sdma.unsolicited_frame_get_pointer);
}

void isci_tci_free(struct isci_host *ihost, u16 tci)
{
u16 tail = ihost->tci_tail & (SCI_MAX_IO_REQUESTS-1);

ihost->tci_pool[tail] = tci;
ihost->tci_tail = tail + 1;
}

static u16 isci_tci_alloc(struct isci_host *ihost)
{
u16 head = ihost->tci_head & (SCI_MAX_IO_REQUESTS-1);
u16 tci = ihost->tci_pool[head];

ihost->tci_head = head + 1;
return tci;
}

static u16 isci_tci_space(struct isci_host *ihost)
{
return CIRC_SPACE(ihost->tci_head, ihost->tci_tail, SCI_MAX_IO_REQUESTS);
}

u16 isci_alloc_tag(struct isci_host *ihost)
{
if (isci_tci_space(ihost)) {
u16 tci = isci_tci_alloc(ihost);
u8 seq = ihost->sci.io_request_sequence[tci];

return ISCI_TAG(seq, tci);
}

return SCI_CONTROLLER_INVALID_IO_TAG;
}

enum sci_status isci_free_tag(struct isci_host *ihost, u16 io_tag)
{
struct scic_sds_controller *scic = &ihost->sci;
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 (seq == scic->io_request_sequence[tci]) {
scic->io_request_sequence[tci] = (seq+1) & (SCI_MAX_SEQ-1);

isci_tci_free(ihost, tci);

return SCI_SUCCESS;
}
return SCI_FAILURE_INVALID_IO_TAG;
}

/**
* scic_controller_start_io() - This method is called by the SCI user to
* send/start an IO request. If the method invocation is successful, then
Expand All @@ -2811,27 +2803,11 @@ void scic_sds_controller_release_frame(
* IO request.
* @io_request: the handle to the io request object to start.
* @io_tag: This parameter specifies a previously allocated IO tag that the
* user desires to be utilized for this request. This parameter is optional.
* The user is allowed to supply SCI_CONTROLLER_INVALID_IO_TAG as the value
* for this parameter.
*
* - IO tags are a protected resource. It is incumbent upon the SCI Core user
* to ensure that each of the methods that may allocate or free available IO
* tags are handled in a mutually exclusive manner. This method is one of said
* methods requiring proper critical code section protection (e.g. semaphore,
* spin-lock, etc.). - For SATA, the user is required to manage NCQ tags. As a
* result, it is expected the user will have set the NCQ tag field in the host
* to device register FIS prior to calling this method. There is also a
* requirement for the user to call scic_stp_io_set_ncq_tag() prior to invoking
* the scic_controller_start_io() method. scic_controller_allocate_tag() for
* more information on allocating a tag. Indicate if the controller
* successfully started the IO request. SCI_SUCCESS if the IO request was
* successfully started. Determine the failure situations and return values.
* user desires to be utilized for this request.
*/
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)
struct scic_sds_request *req)
{
enum sci_status status;

Expand Down Expand Up @@ -2902,17 +2878,6 @@ enum sci_status scic_controller_terminate_request(
* @remote_device: The handle to the remote device object for which to complete
* the IO request.
* @io_request: the handle to the io request object to complete.
*
* - IO tags are a protected resource. It is incumbent upon the SCI Core user
* to ensure that each of the methods that may allocate or free available IO
* tags are handled in a mutually exclusive manner. This method is one of said
* methods requiring proper critical code section protection (e.g. semaphore,
* spin-lock, etc.). - If the IO tag for a request was allocated, by the SCI
* Core user, using the scic_controller_allocate_io_tag() method, then it is
* the responsibility of the caller to invoke the scic_controller_free_io_tag()
* method to free the tag (i.e. this method will not free the IO tag). Indicate
* if the controller successfully completed the IO request. SCI_SUCCESS if the
* completion process was successful.
*/
enum sci_status scic_controller_complete_io(
struct scic_sds_controller *scic,
Expand Down Expand Up @@ -2963,31 +2928,11 @@ enum sci_status scic_controller_continue_io(struct scic_sds_request *sci_req)
* @remote_device: the handle to the remote device object for which to start
* the task management request.
* @task_request: the handle to the task request object to start.
* @io_tag: This parameter specifies a previously allocated IO tag that the
* user desires to be utilized for this request. Note this not the io_tag
* of the request being managed. It is to be utilized for the task request
* itself. This parameter is optional. The user is allowed to supply
* SCI_CONTROLLER_INVALID_IO_TAG as the value for this parameter.
*
* - IO tags are a protected resource. It is incumbent upon the SCI Core user
* to ensure that each of the methods that may allocate or free available IO
* tags are handled in a mutually exclusive manner. This method is one of said
* methods requiring proper critical code section protection (e.g. semaphore,
* spin-lock, etc.). - The user must synchronize this task with completion
* queue processing. If they are not synchronized then it is possible for the
* io requests that are being managed by the task request can complete before
* starting the task request. scic_controller_allocate_tag() for more
* information on allocating a tag. Indicate if the controller successfully
* started the IO request. SCI_TASK_SUCCESS if the task request was
* successfully started. SCI_TASK_FAILURE_REQUIRES_SCSI_ABORT This value is
* returned if there is/are task(s) outstanding that require termination or
* completion before this request can succeed.
*/
enum sci_task_status scic_controller_start_task(
struct scic_sds_controller *scic,
struct scic_sds_remote_device *rdev,
struct scic_sds_request *req,
u16 task_tag)
struct scic_sds_request *req)
{
enum sci_status status;

Expand Down Expand Up @@ -3022,85 +2967,3 @@ enum sci_task_status scic_controller_start_task(

return status;
}

/**
* scic_controller_allocate_io_tag() - This method will allocate a tag from the
* pool of free IO tags. Direct allocation of IO tags by the SCI Core user
* is optional. The scic_controller_start_io() method will allocate an IO
* tag if this method is not utilized and the tag is not supplied to the IO
* construct routine. Direct allocation of IO tags may provide additional
* performance improvements in environments capable of supporting this usage
* model. Additionally, direct allocation of IO tags also provides
* additional flexibility to the SCI Core user. Specifically, the user may
* retain IO tags across the lives of multiple IO requests.
* @controller: the handle to the controller object for which to allocate the
* tag.
*
* IO tags are a protected resource. It is incumbent upon the SCI Core user to
* ensure that each of the methods that may allocate or free available IO tags
* are handled in a mutually exclusive manner. This method is one of said
* methods requiring proper critical code section protection (e.g. semaphore,
* spin-lock, etc.). An unsigned integer representing an available IO tag.
* SCI_CONTROLLER_INVALID_IO_TAG This value is returned if there are no
* currently available tags to be allocated. All return other values indicate a
* legitimate tag.
*/
u16 scic_controller_allocate_io_tag(struct scic_sds_controller *scic)
{
struct isci_host *ihost = scic_to_ihost(scic);

if (isci_tci_space(ihost)) {
u16 tci = isci_tci_alloc(ihost);
u8 seq = scic->io_request_sequence[tci];

return ISCI_TAG(seq, tci);
}

return SCI_CONTROLLER_INVALID_IO_TAG;
}

/**
* scic_controller_free_io_tag() - This method will free an IO tag to the pool
* of free IO tags. This method provides the SCI Core user more flexibility
* with regards to IO tags. The user may desire to keep an IO tag after an
* IO request has completed, because they plan on re-using the tag for a
* subsequent IO request. This method is only legal if the tag was
* allocated via scic_controller_allocate_io_tag().
* @controller: This parameter specifies the handle to the controller object
* for which to free/return the tag.
* @io_tag: This parameter represents the tag to be freed to the pool of
* available tags.
*
* - IO tags are a protected resource. It is incumbent upon the SCI Core user
* to ensure that each of the methods that may allocate or free available IO
* tags are handled in a mutually exclusive manner. This method is one of said
* methods requiring proper critical code section protection (e.g. semaphore,
* spin-lock, etc.). - If the IO tag for a request was allocated, by the SCI
* Core user, using the scic_controller_allocate_io_tag() method, then it is
* the responsibility of the caller to invoke this method to free the tag. This
* method returns an indication of whether the tag was successfully put back
* (freed) to the pool of available tags. SCI_SUCCESS This return value
* indicates the tag was successfully placed into the pool of available IO
* tags. SCI_FAILURE_INVALID_IO_TAG This value is returned if the supplied tag
* is not a valid IO tag value.
*/
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 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 (seq == scic->io_request_sequence[tci]) {
scic->io_request_sequence[tci] = (seq+1) & (SCI_MAX_SEQ-1);

isci_tci_free(ihost, ISCI_TAG_TCI(io_tag));

return SCI_SUCCESS;
}
return SCI_FAILURE_INVALID_IO_TAG;
}
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