From 88e1b59ee30950a66ea28b740914bf603fa9a1ec Mon Sep 17 00:00:00 2001 From: Aaron Hill Date: Thu, 15 Aug 2019 09:46:42 +0100 Subject: [PATCH] Set ENET_BD_BDU in I.MX FEC controller This commit properly sets the ENET_BD_BDU flag once the emulated FEC controller has finished processing the last descriptor. This is done for both transmit and receive descriptors. This allows the QNX 7.0.0 BSP for the Sabrelite board (which can be found at http://blackberry.qnx.com/en/developers/bsp) to properly control the FEC. Without this patch, the BSP ethernet driver will never re-use FEC descriptors, as the unset ENET_BD_BDU flag will cause it to believe that the descriptors are still in use by the NIC. Note that Linux does not appear to use this field at all, and is unaffected by this patch. Without this patch, QNX will think that the NIC is still processing its transaction descriptors, and won't send any more data over the network. For reference: On page 1192 of the I.MX 6DQ reference manual revision (Rev. 5, 06/2018), which can be found at https://www.nxp.com/products/processors-and-microcontrollers/arm-based-processors-and-mcus/i.mx-applications-processors/i.mx-6-processors/i.mx-6quad-processors-high-performance-3d-graphics-hd-video-arm-cortex-a9-core:i.MX6Q?&tab=Documentation_Tab&linkline=Application-Note the 'BDU' field is described as follows for the 'Enhanced transmit buffer descriptor': 'Last buffer descriptor update done. Indicates that the last BD data has been updated by uDMA. This field is written by the user (=0) and uDMA (=1).' The same description is used for the receive buffer descriptor. Signed-off-by: Aaron Hill Message-id: 20190805142417.10433-1-aaron.hill@alertinnovation.com Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- hw/net/imx_fec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c index 404154ebbf..4693bfb246 100644 --- a/hw/net/imx_fec.c +++ b/hw/net/imx_fec.c @@ -590,6 +590,8 @@ static void imx_enet_do_tx(IMXFECState *s, uint32_t index) if (bd.option & ENET_BD_TX_INT) { s->regs[ENET_EIR] |= int_txf; } + /* Indicate that we've updated the last buffer descriptor. */ + bd.last_buffer = ENET_BD_BDU; } if (bd.option & ENET_BD_TX_INT) { s->regs[ENET_EIR] |= int_txb; @@ -1239,6 +1241,8 @@ static ssize_t imx_enet_receive(NetClientState *nc, const uint8_t *buf, /* Last buffer in frame. */ bd.flags |= flags | ENET_BD_L; FEC_PRINTF("rx frame flags %04x\n", bd.flags); + /* Indicate that we've updated the last buffer descriptor. */ + bd.last_buffer = ENET_BD_BDU; if (bd.option & ENET_BD_RX_INT) { s->regs[ENET_EIR] |= ENET_INT_RXF; }