diff options
Diffstat (limited to 'drivers/spi/spi-pl022.c')
| -rw-r--r-- | drivers/spi/spi-pl022.c | 72 |
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); |