Patch "spi/spi-xilinx: Fix spurious IRQ ACK on irq mode" has been added to the 4.2-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
spi-spi-xilinx-fix-spurious-irq-ack-on-irq-mode.patch
and it can be found in the queue-4.2 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ricardo Ribalda Delgado <[email protected]>
Date: Thu, 13 Aug 2015 16:09:28 +0200
Subject: spi/spi-xilinx: Fix spurious IRQ ACK on irq mode

From: Ricardo Ribalda Delgado <[email protected]>

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.

---
 drivers/spi/spi-xilinx.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

@@ -249,19 +249,23 @@ static int xilinx_spi_txrx_bufs(struct s
 	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) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.2/spi-spi-xilinx-fix-mixed-poll-irq-mode.patch queue-4.2/spi-spi-xilinx-fix-spurious-irq-ack-on-irq-mode.patch