From 6319a68011b86fa61dc63e94dc4fb716628037f3 Mon Sep 17 00:00:00 2001 From: Nobuteru Hayashi Date: Fri, 18 Mar 2016 11:35:21 +0000 Subject: [PATCH] spi/fsl-espi: avoid infinite loops on fsl_espi_cpu_irq() It brought nearly infinite loops, and was possible to be occurred only if the SPI transaction total size are not alighed with 4. Loops are here at while (tmp--), tmp is unsigned, and set it with minus value. The loops are executed as a result of unexpected RX interrupt occurrence after that. This interrupt may be hardware eratta and is not fixed. Fix mspi->len from minus value to 0 and print warning message. Signed-off-by: Nobuteru Hayashi Signed-off-by: Mark Brown --- drivers/spi/spi-fsl-espi.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c index 64d794b99803..8d85a3c343da 100644 --- a/drivers/spi/spi-fsl-espi.c +++ b/drivers/spi/spi-fsl-espi.c @@ -544,6 +544,7 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events) if (events & SPIE_NE) { u32 rx_data, tmp; u8 rx_data_8; + int rx_nr_bytes = 4; int ret; /* Spin until RX is done */ @@ -560,7 +561,14 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events) if (mspi->len >= 4) { rx_data = mpc8xxx_spi_read_reg(®_base->receive); + } else if (mspi->len <= 0) { + dev_err(mspi->dev, + "unexpected RX(SPIE_NE) interrupt occurred,\n" + "(local rxlen %d bytes, reg rxlen %d bytes)\n", + min(4, mspi->len), SPIE_RXCNT(events)); + rx_nr_bytes = 0; } else { + rx_nr_bytes = mspi->len; tmp = mspi->len; rx_data = 0; while (tmp--) { @@ -571,7 +579,7 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events) rx_data <<= (4 - mspi->len) * 8; } - mspi->len -= 4; + mspi->len -= rx_nr_bytes; if (mspi->rx) mspi->get_rx(rx_data, mspi);