[PATCH 4/5] spi: bcm-qspi: Make multiple data blocks interrupt-driven

[Mark Tomlinson]

When needing to send/receive data in small chunks, make this interrupt
driven rather than waiting for a completion event for each small section
of data.

Reviewed-by: Callum Sinclair <callum.sincl...@alliedtelesis.co.nz>
Reviewed-by: Chris Packham <chris.pack...@alliedtelesis.co.nz>
Signed-off-by: Mark Tomlinson <mark.tomlin...@alliedtelesis.co.nz>
---
 drivers/spi/spi-bcm-qspi.c | 44 ++++++++++++++++++++++++--------------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index ce30ebf27f06..0cc51bcda300 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -200,12 +200,14 @@ struct bcm_qspi_dev_id {
 struct qspi_trans {
        struct spi_transfer *trans;
        int byte;
+       int slots;
        bool mspi_last_trans;
 };
 
 struct bcm_qspi {
        struct platform_device *pdev;
        struct spi_master *master;
+       struct spi_device *spi_dev;
        struct clk *clk;
        u32 base_clk;
        u32 max_speed_hz;
@@ -731,12 +733,14 @@ static inline u16 read_rxram_slot_u16(struct bcm_qspi 
*qspi, int slot)
                ((bcm_qspi_read(qspi, MSPI, msb_offset) & 0xff) << 8);
 }
 
-static void read_from_hw(struct bcm_qspi *qspi, int slots)
+static void read_from_hw(struct bcm_qspi *qspi)
 {
        struct qspi_trans tp;
-       int slot;
+       int slot, slots;
 
        bcm_qspi_disable_bspi(qspi);
+       tp = qspi->trans_pos;
+       slots = tp.slots;
 
        if (slots > MSPI_NUM_CDRAM) {
                /* should never happen */
@@ -744,8 +748,6 @@ static void read_from_hw(struct bcm_qspi *qspi, int slots)
                return;
        }
 
-       tp = qspi->trans_pos;
-
        for (slot = 0; slot < slots; slot++) {
                if (tp.trans->rx_buf) {
                        if (tp.trans->bits_per_word <= 8) {
@@ -803,11 +805,12 @@ static inline void write_cdram_slot(struct bcm_qspi 
*qspi, int slot, u32 val)
 }
 
 /* Return number of slots written */
-static int write_to_hw(struct bcm_qspi *qspi, struct spi_device *spi)
+static int write_to_hw(struct bcm_qspi *qspi)
 {
        struct qspi_trans tp;
        int slot = 0, tstatus = 0;
        u32 mspi_cdram = 0;
+       struct spi_device *spi = qspi->spi_dev;
 
        bcm_qspi_disable_bspi(qspi);
        tp = qspi->trans_pos;
@@ -846,6 +849,9 @@ static int write_to_hw(struct bcm_qspi *qspi, struct 
spi_device *spi)
                slot++;
        }
 
+       /* save slot number for read_from_hw() */
+       qspi->trans_pos.slots = slot;
+
        if (!slot) {
                dev_err(&qspi->pdev->dev, "%s: no data to send?", __func__);
                goto done;
@@ -960,24 +966,21 @@ static int bcm_qspi_transfer_one(struct spi_master 
*master,
                                 struct spi_transfer *trans)
 {
        struct bcm_qspi *qspi = spi_master_get_devdata(master);
-       int slots;
-       unsigned long timeo = msecs_to_jiffies(100);
+       unsigned long timeo = msecs_to_jiffies(1000);
 
        if (!spi->cs_gpiod)
                bcm_qspi_chip_select(qspi, spi->chip_select);
        qspi->trans_pos.trans = trans;
        qspi->trans_pos.byte = 0;
+       qspi->spi_dev = spi;
 
-       while (qspi->trans_pos.byte < trans->len) {
-               reinit_completion(&qspi->mspi_done);
+       reinit_completion(&qspi->mspi_done);
 
-               slots = write_to_hw(qspi, spi);
-               if (!wait_for_completion_timeout(&qspi->mspi_done, timeo)) {
-                       dev_err(&qspi->pdev->dev, "timeout waiting for MSPI\n");
-                       return -ETIMEDOUT;
-               }
+       write_to_hw(qspi);
 
-               read_from_hw(qspi, slots);
+       if (!wait_for_completion_timeout(&qspi->mspi_done, timeo)) {
+               dev_err(&qspi->pdev->dev, "timeout waiting for MSPI\n");
+               return -ETIMEDOUT;
        }
        bcm_qspi_enable_bspi(qspi);
 
@@ -1092,7 +1095,16 @@ static irqreturn_t bcm_qspi_mspi_l2_isr(int irq, void 
*dev_id)
                bcm_qspi_write(qspi, MSPI, MSPI_MSPI_STATUS, status);
                if (qspi->soc_intc)
                        soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_DONE);
-               complete(&qspi->mspi_done);
+
+               read_from_hw(qspi);
+
+               if (qspi->trans_pos.trans) {
+                       write_to_hw(qspi);
+               } else {
+                       complete(&qspi->mspi_done);
+                       spi_finalize_current_transfer(qspi->master);
+               }
+
                return IRQ_HANDLED;
        }
 
-- 
2.27.0