From 844ad96638166682d15aa13295c181ed7bf963aa Mon Sep 17 00:00:00 2001 From: Mark Cave-Ayland Date: Mon, 7 Aug 2023 07:52:58 +0100 Subject: esp-scsi: flush FIFO before sending SCSI command MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The ESP FIFO is used as a buffer for DMA requests and so isn't guaranteed to be empty in the case of SCSI errors or a mixed DMA/non-DMA request. Flush the FIFO before sending a SCSI command to guarantee that it is correctly positioned at the start of the FIFO. Signed-off-by: Mark Cave-Ayland Reviewed-by: Paolo Bonzini Reviewed-by: Philippe Mathieu-Daudé Message-ID: <20230807065300.366070-2-mark.cave-ayland@ilande.co.uk> Signed-off-by: Gerd Hoffmann --- src/hw/esp-scsi.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/hw/esp-scsi.c b/src/hw/esp-scsi.c index 3282437..06ef20d 100644 --- a/src/hw/esp-scsi.c +++ b/src/hw/esp-scsi.c @@ -46,6 +46,7 @@ #define ESP_DMA_WMAC 0x58c #define ESP_CMD_DMA 0x80 +#define ESP_CMD_FLUSH 0x01 #define ESP_CMD_RESET 0x02 #define ESP_CMD_TI 0x10 #define ESP_CMD_ICCS 0x11 @@ -96,6 +97,9 @@ esp_scsi_process_op(struct disk_op_s *op) outb(target, iobase + ESP_WBUSID); + /* Clear FIFO before sending command. */ + outb(ESP_CMD_FLUSH, iobase + ESP_CMD); + /* * We need to pass the LUN at the beginning of the command, and the FIFO * is only 16 bytes, so we cannot support 16-byte CDBs. The alternative -- cgit v1.1