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path: root/drivers/spi/spi-pl022.c
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Diffstat (limited to 'drivers/spi/spi-pl022.c')
-rw-r--r--drivers/spi/spi-pl022.c72
1 files changed, 37 insertions, 35 deletions
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index 13988a3024b..1cff8ad470d 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -340,6 +340,10 @@ struct vendor_data {
* @cur_msg: Pointer to current spi_message being processed
* @cur_transfer: Pointer to current spi_transfer
* @cur_chip: pointer to current clients chip(assigned from controller_state)
+ * @next_msg_cs_active: the next message in the queue has been examined
+ * and it was found that it uses the same chip select as the previous
+ * message, so we left it active after the previous transfer, and it's
+ * active already.
* @tx: current position in TX buffer to be read
* @tx_end: end position in TX buffer to be read
* @rx: current position in RX buffer to be written
@@ -373,6 +377,7 @@ struct pl022 {
struct spi_message *cur_msg;
struct spi_transfer *cur_transfer;
struct chip_data *cur_chip;
+ bool next_msg_cs_active;
void *tx;
void *tx_end;
void *rx;
@@ -445,23 +450,9 @@ static void giveback(struct pl022 *pl022)
struct spi_transfer *last_transfer;
unsigned long flags;
struct spi_message *msg;
- void (*curr_cs_control) (u32 command);
+ pl022->next_msg_cs_active = false;
- /*
- * This local reference to the chip select function
- * is needed because we set curr_chip to NULL
- * as a step toward termininating the message.
- */
- curr_cs_control = pl022->cur_chip->cs_control;
- spin_lock_irqsave(&pl022->queue_lock, flags);
- msg = pl022->cur_msg;
- pl022->cur_msg = NULL;
- pl022->cur_transfer = NULL;
- pl022->cur_chip = NULL;
- queue_work(pl022->workqueue, &pl022->pump_messages);
- spin_unlock_irqrestore(&pl022->queue_lock, flags);
-
- last_transfer = list_entry(msg->transfers.prev,
+ last_transfer = list_entry(pl022->cur_msg->transfers.prev,
struct spi_transfer,
transfer_list);
@@ -473,18 +464,13 @@ static void giveback(struct pl022 *pl022)
*/
udelay(last_transfer->delay_usecs);
- /*
- * Drop chip select UNLESS cs_change is true or we are returning
- * a message with an error, or next message is for another chip
- */
- if (!last_transfer->cs_change)
- curr_cs_control(SSP_CHIP_DESELECT);
- else {
+ if (!last_transfer->cs_change) {
struct spi_message *next_msg;
- /* Holding of cs was hinted, but we need to make sure
- * the next message is for the same chip. Don't waste
- * time with the following tests unless this was hinted.
+ /*
+ * cs_change was not set. We can keep the chip select
+ * enabled if there is message in the queue and it is
+ * for the same spi device.
*
* We cannot postpone this until pump_messages, because
* after calling msg->complete (below) the driver that
@@ -501,14 +487,26 @@ static void giveback(struct pl022 *pl022)
struct spi_message, queue);
spin_unlock_irqrestore(&pl022->queue_lock, flags);
- /* see if the next and current messages point
- * to the same chip
+ /*
+ * see if the next and current messages point
+ * to the same spi device.
*/
- if (next_msg && next_msg->spi != msg->spi)
+ if (next_msg && next_msg->spi != pl022->cur_msg->spi)
next_msg = NULL;
- if (!next_msg || msg->state == STATE_ERROR)
- curr_cs_control(SSP_CHIP_DESELECT);
+ if (!next_msg || pl022->cur_msg->state == STATE_ERROR)
+ pl022->cur_chip->cs_control(SSP_CHIP_DESELECT);
+ else
+ pl022->next_msg_cs_active = true;
}
+
+ spin_lock_irqsave(&pl022->queue_lock, flags);
+ msg = pl022->cur_msg;
+ pl022->cur_msg = NULL;
+ pl022->cur_transfer = NULL;
+ pl022->cur_chip = NULL;
+ queue_work(pl022->workqueue, &pl022->pump_messages);
+ spin_unlock_irqrestore(&pl022->queue_lock, flags);
+
msg->state = NULL;
if (msg->complete)
msg->complete(msg->context);
@@ -1350,7 +1348,7 @@ static void pump_transfers(unsigned long data)
*/
udelay(previous->delay_usecs);
- /* Drop chip select only if cs_change is requested */
+ /* Reselect chip select only if cs_change was requested */
if (previous->cs_change)
pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
} else {
@@ -1389,8 +1387,10 @@ static void do_interrupt_dma_transfer(struct pl022 *pl022)
*/
u32 irqflags = ENABLE_ALL_INTERRUPTS & ~SSP_IMSC_MASK_RXIM;
- /* Enable target chip */
- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+ /* Enable target chip, if not already active */
+ if (!pl022->next_msg_cs_active)
+ pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+
if (set_up_next_transfer(pl022, pl022->cur_transfer)) {
/* Error path */
pl022->cur_msg->state = STATE_ERROR;
@@ -1445,7 +1445,8 @@ static void do_polling_transfer(struct pl022 *pl022)
} else {
/* STATE_START */
message->state = STATE_RUNNING;
- pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
+ if (!pl022->next_msg_cs_active)
+ pl022->cur_chip->cs_control(SSP_CHIP_SELECT);
}
/* Configuration Changing Per Transfer */
@@ -1604,6 +1605,7 @@ static int start_queue(struct pl022 *pl022)
pl022->cur_msg = NULL;
pl022->cur_transfer = NULL;
pl022->cur_chip = NULL;
+ pl022->next_msg_cs_active = false;
spin_unlock_irqrestore(&pl022->queue_lock, flags);
queue_work(pl022->workqueue, &pl022->pump_messages);