spi/spi-xilinx: Fix spurious IRQ ACK on irq mode

commit 74346841e6f5df5f7b83d5904435d273c507dba6 upstream.

The ACK of an inexistent IRQ can trigger an spurious IRQ that breaks the
txrx logic. This has been observed on axi_quad_spi:3.2 core.

This patch only ACKs IRQs that have not been Acknowledge jet.

Reported-by: Edward Kigwana <ekigwana@scires.com>
Tested-by: Edward Kigwana <ekigwana@scires.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c
index 133f53a9c1d4eb9b5235b88de03dac9c5d2ea27e..8a81a692f764dcef537b097c8a6c1b3d78f34d8b 100644 (file)
--- a/drivers/spi/spi-xilinx.c
+++ b/drivers/spi/spi-xilinx.c
@@ -249,19 +249,23 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
        xspi->tx_ptr = t->tx_buf;
        xspi->rx_ptr = t->rx_buf;
        remaining_words = t->len / xspi->bytes_per_word;
-       reinit_completion(&xspi->done);
 
        if (xspi->irq >= 0 &&  remaining_words > xspi->buffer_size) {
+               u32 isr;
                use_irq = true;
-               xspi->write_fn(XSPI_INTR_TX_EMPTY,
-                               xspi->regs + XIPIF_V123B_IISR_OFFSET);
-               /* Enable the global IPIF interrupt */
-               xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
-                               xspi->regs + XIPIF_V123B_DGIER_OFFSET);
                /* Inhibit irq to avoid spurious irqs on tx_empty*/
                cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
                xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
                               xspi->regs + XSPI_CR_OFFSET);
+               /* ACK old irqs (if any) */
+               isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+               if (isr)
+                       xspi->write_fn(isr,
+                                      xspi->regs + XIPIF_V123B_IISR_OFFSET);
+               /* Enable the global IPIF interrupt */
+               xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
+                               xspi->regs + XIPIF_V123B_DGIER_OFFSET);
+               reinit_completion(&xspi->done);
        }
 
        while (remaining_words) {