[PATCH v2 4/6] esp_scsi: Eliminate ESP_FLAG_DOING_SLOWCMD

Finn Thain
2018-10-14T06:34:44Z

The concept of a 'slow command' as it appears in esp_scsi is confusing
because it could refer to an ESP command or a SCSI command. It turns out
that it refers to a particular ESP select command which the driver also
tracks as 'ESP_SELECT_MSGOUT'. For readability, it is better to use the
terminology from the datasheets.

The global ESP_FLAG_DOING_SLOWCMD flag is redundant anyway, as it can be
inferred from esp->select_state. Remove the ESP_FLAG_DOING_SLOWCMD cruft
and just use a boolean local variable.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
---
drivers/scsi/esp_scsi.c | 57 +++++++++++++++++------------------------
drivers/scsi/esp_scsi.h | 3 +--
2 files changed, 24 insertions(+), 36 deletions(-)

diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c
index b7c41aa9927c..6ccaf818357e 100644
--- a/drivers/scsi/esp_scsi.c
+++ b/drivers/scsi/esp_scsi.c
@@ -478,17 +478,6 @@ static void esp_restore_pointers(struct esp *esp, struct esp_cmd_entry *ent)
spriv->tot_residue = ent->saved_tot_residue;
}

-static void esp_check_command_len(struct esp *esp, struct scsi_cmnd *cmd)
-{
- if (cmd->cmd_len == 6 ||
- cmd->cmd_len == 10 ||
- cmd->cmd_len == 12) {
- esp->flags &= ~ESP_FLAG_DOING_SLOWCMD;
- } else {
- esp->flags |= ESP_FLAG_DOING_SLOWCMD;
- }
-}
-
static void esp_write_tgt_config3(struct esp *esp, int tgt)
{
if (esp->rev > ESP100A) {
@@ -721,6 +710,7 @@ static void esp_maybe_execute_command(struct esp *esp)
struct scsi_device *dev;
struct scsi_cmnd *cmd;
struct esp_cmd_entry *ent;
+ bool select_and_stop = false;
int tgt, lun, i;
u32 val, start_cmd;
u8 *p;
@@ -752,7 +742,8 @@ static void esp_maybe_execute_command(struct esp *esp)
esp_map_dma(esp, cmd);
esp_save_pointers(esp, ent);

- esp_check_command_len(esp, cmd);
+ if (!(cmd->cmd_len == 6 || cmd->cmd_len == 10 || cmd->cmd_len == 12))
+ select_and_stop = true;

p = esp->command_block;

@@ -793,9 +784,9 @@ static void esp_maybe_execute_command(struct esp *esp)
tp->flags &= ~ESP_TGT_CHECK_NEGO;
}

- /* Process it like a slow command. */
- if (tp->flags & (ESP_TGT_NEGO_WIDE | ESP_TGT_NEGO_SYNC))
- esp->flags |= ESP_FLAG_DOING_SLOWCMD;
+ /* If there are multiple message bytes, use Select and Stop */
+ if (esp->msg_out_len)
+ select_and_stop = true;
}

build_identify:
@@ -808,23 +799,10 @@ static void esp_maybe_execute_command(struct esp *esp)
/* ESP100 lacks select w/atn3 command, use select
* and stop instead.
*/
- esp->flags |= ESP_FLAG_DOING_SLOWCMD;
+ select_and_stop = true;
}

- if (!(esp->flags & ESP_FLAG_DOING_SLOWCMD)) {
- start_cmd = ESP_CMD_SELA;
- if (ent->tag[0]) {
- *p++ = ent->tag[0];
- *p++ = ent->tag[1];
-
- start_cmd = ESP_CMD_SA3;
- }
-
- for (i = 0; i < cmd->cmd_len; i++)
- *p++ = cmd->cmnd[i];
-
- esp->select_state = ESP_SELECT_BASIC;
- } else {
+ if (select_and_stop) {
esp->cmd_bytes_left = cmd->cmd_len;
esp->cmd_bytes_ptr = &cmd->cmnd[0];

@@ -839,6 +817,19 @@ static void esp_maybe_execute_command(struct esp *esp)

start_cmd = ESP_CMD_SELAS;
esp->select_state = ESP_SELECT_MSGOUT;
+ } else {
+ start_cmd = ESP_CMD_SELA;
+ if (ent->tag[0]) {
+ *p++ = ent->tag[0];
+ *p++ = ent->tag[1];
+
+ start_cmd = ESP_CMD_SA3;
+ }
+
+ for (i = 0; i < cmd->cmd_len; i++)
+ *p++ = cmd->cmnd[i];
+
+ esp->select_state = ESP_SELECT_BASIC;
}
val = tgt;
if (esp->rev == FASHME)
@@ -1248,7 +1239,6 @@ static int esp_finish_select(struct esp *esp)
esp_unmap_dma(esp, cmd);
esp_free_lun_tag(ent, cmd->device->hostdata);
tp->flags &= ~(ESP_TGT_NEGO_SYNC | ESP_TGT_NEGO_WIDE);
- esp->flags &= ~ESP_FLAG_DOING_SLOWCMD;
esp->cmd_bytes_ptr = NULL;
esp->cmd_bytes_left = 0;
} else {
@@ -1299,9 +1289,8 @@ static int esp_finish_select(struct esp *esp)
esp_flush_fifo(esp);
}

- /* If we are doing a slow command, negotiation, etc.
- * we'll do the right thing as we transition to the
- * next phase.
+ /* If we are doing a Select And Stop command, negotiation, etc.
+ * we'll do the right thing as we transition to the next phase.
*/
esp_event(esp, ESP_EVENT_CHECK_PHASE);
return 0;
diff --git a/drivers/scsi/esp_scsi.h b/drivers/scsi/esp_scsi.h
index db4b6ea94caa..d0c032803749 100644
--- a/drivers/scsi/esp_scsi.h
+++ b/drivers/scsi/esp_scsi.h
@@ -490,7 +490,6 @@ struct esp {
u32 flags;
#define ESP_FLAG_DIFFERENTIAL 0x00000001
#define ESP_FLAG_RESETTING 0x00000002
-#define ESP_FLAG_DOING_SLOWCMD 0x00000004
#define ESP_FLAG_WIDE_CAPABLE 0x00000008
#define ESP_FLAG_QUICKIRQ_CHECK 0x00000010
#define ESP_FLAG_DISABLE_SYNC 0x00000020
@@ -532,7 +531,7 @@ struct esp {
u32 min_period;
u32 radelay;

- /* Slow command state. */
+ /* ESP_CMD_SELAS command state */
u8 *cmd_bytes_ptr;
int cmd_bytes_left;

--
2.18.1