From bd2d5021ba5cd668d8fe2f8f4fe33d89cdb9235e Mon Sep 17 00:00:00 2001 From: Jonathan Bell Date: Mon, 22 Jul 2024 15:27:51 +0100 Subject: [PATCH] spi: dw: don't immediately kill DMA transfers if an error occurs Disabling the peripheral resets controller state which has a dangerous side-effect of disabling the DMA handshake interface while it is active. This can cause DMA channels to hang. The error recovery pathway will wait for DMA to stop and reset the chip anyway, so mask further FIFO interrupts and let the transfer finish gracefully. Signed-off-by: Jonathan Bell --- drivers/spi/spi-dw-core.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -202,7 +202,18 @@ int dw_spi_check_status(struct dw_spi *d /* Generically handle the erroneous situation */ if (ret) { - dw_spi_reset_chip(dws); + /* + * Forcibly halting the controller can cause DMA to hang. + * Defer to dw_spi_handle_err outside of interrupt context + * and mask further interrupts for the current transfer. + */ + if (dws->dma_mapped) { + dw_spi_mask_intr(dws, 0xff); + dw_readl(dws, DW_SPI_ICR); + } else { + dw_spi_reset_chip(dws); + } + if (dws->host->cur_msg) dws->host->cur_msg->status = ret; }