From 89fcdd53c2528b8f0ed34553aaf9826fe63848b5 Mon Sep 17 00:00:00 2001 From: Martin Sperl Date: Tue, 19 Jul 2022 12:53:05 +0200 Subject: [PATCH] spi: bcm2835: enable shared interrupt support BCM2711 shares an interrupt betweem 5 SPI interfaces (0, 3, 4, 5 & 6). Another interrupt is shared between SPI1, SPI2 and UART1, which also affects BCM2835/6/7. Acting on an interrupt intended for another interface ought to be harmless (although potentially inefficient), but it can cause this driver to crash - presumably because some critical state is not ready. Add a test to the spi-bcm2835 interrupt service routine that interrupts are enabled on this interface to avoid the crash and improve efficiency. Signed-off-by: Martin Sperl Link: https://github.com/raspberrypi/linux/issues/5048 Suggested-by: https://github.com/boe-pi Co-developed-by: Phil Elwell Signed-off-by: Phil Elwell Cc: Mark Brown Cc: Lukas Wunner Signed-off-by: Marc Kleine-Budde Link: https://lore.kernel.org/r/20220719105305.3076354-1-mkl@pengutronix.de Signed-off-by: Mark Brown --- drivers/spi/spi-bcm2835.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c index 775c0bf2f923d..9bdb1b85ae08a 100644 --- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -372,6 +372,10 @@ static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id) struct bcm2835_spi *bs = dev_id; u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS); + /* Bail out early if interrupts are not enabled */ + if (!(cs & BCM2835_SPI_CS_INTR)) + return IRQ_NONE; + /* * An interrupt is signaled either if DONE is set (TX FIFO empty) * or if RXR is set (RX FIFO >= ¾ full). @@ -1365,8 +1369,8 @@ static int bcm2835_spi_probe(struct platform_device *pdev) bcm2835_wr(bs, BCM2835_SPI_CS, BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX); - err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0, - dev_name(&pdev->dev), bs); + err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, + IRQF_SHARED, dev_name(&pdev->dev), bs); if (err) { dev_err(&pdev->dev, "could not request IRQ: %d\n", err); goto out_dma_release; -- 2.30.2