QEMU-Devel Archive on lore.kernel.org
 help / color / Atom feed
From: Peter Maydell <peter.maydell@linaro.org>
To: qemu-devel@nongnu.org
Subject: [Qemu-devel] [PULL 03/29] Set ENET_BD_BDU in I.MX FEC controller
Date: Fri, 16 Aug 2019 14:16:53 +0100
Message-ID: <20190816131719.28244-4-peter.maydell@linaro.org> (raw)
In-Reply-To: <20190816131719.28244-1-peter.maydell@linaro.org>

From: Aaron Hill <aa1ronham@gmail.com>

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 <aa1ronham@gmail.com>
Message-id: 20190805142417.10433-1-aaron.hill@alertinnovation.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 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 404154ebbf7..4693bfb2464 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;
             }
-- 
2.20.1



  parent reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-16 13:16 [Qemu-devel] [PULL 00/29] target-arm queue Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 01/29] target/arm: generate a custom MIDR for -cpu max Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 02/29] hw/misc/zynq_slcr: use standard register definition Peter Maydell
2019-08-16 13:16 ` Peter Maydell [this message]
2019-08-16 13:16 ` [Qemu-devel] [PULL 04/29] target/arm: Factor out 'generate singlestep exception' function Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 05/29] target/arm: Fix routing of singlestep exceptions Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 06/29] target/arm: Pass in pc to thumb_insn_is_16bit Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 07/29] target/arm: Introduce pc_curr Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 08/29] target/arm: Introduce read_pc Peter Maydell
2019-08-16 13:16 ` [Qemu-devel] [PULL 09/29] target/arm: Introduce add_reg_for_lit Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 10/29] target/arm: Remove redundant s->pc & ~1 Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 11/29] target/arm: Replace s->pc with s->base.pc_next Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 12/29] target/arm: Replace offset with pc in gen_exception_insn Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 13/29] target/arm: Replace offset with pc in gen_exception_internal_insn Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 14/29] target/arm: Remove offset argument to gen_exception_bkpt_insn Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 15/29] target/arm: Use unallocated_encoding for aarch32 Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 16/29] target/arm: Remove helper_double_saturate Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 17/29] target/arm/cpu64: Ensure kvm really supports aarch64=off Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 18/29] target/arm/cpu: Ensure we can use the pmu with kvm Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 19/29] target/arm/helper: zcr: Add build bug next to value range assumption Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 20/29] target/arm/cpu: Use div-round-up to determine predicate register array size Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 21/29] target/arm/kvm64: Fix error returns Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 22/29] target/arm/kvm64: Move the get/put of fpsimd registers out Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 23/29] target/arm: Use tcg_gen_extract_i32 for shifter_out_im Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 24/29] target/arm: Use tcg_gen_deposit_i32 for PKHBT, PKHTB Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 25/29] target/arm: Remove redundant shift tests Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 26/29] target/arm: Use ror32 instead of open-coding the operation Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 27/29] target/arm: Use tcg_gen_rotri_i32 for gen_swap_half Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 28/29] target/arm: Simplify SMMLA, SMMLAR, SMMLS, SMMLSR Peter Maydell
2019-08-16 13:17 ` [Qemu-devel] [PULL 29/29] target/arm: Use tcg_gen_extrh_i64_i32 to extract the high word Peter Maydell
2019-08-16 17:02 ` [Qemu-devel] [PULL 00/29] target-arm queue Peter Maydell

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190816131719.28244-4-peter.maydell@linaro.org \
    --to=peter.maydell@linaro.org \
    --cc=qemu-devel@nongnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

QEMU-Devel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/qemu-devel/0 qemu-devel/git/0.git
	git clone --mirror https://lore.kernel.org/qemu-devel/1 qemu-devel/git/1.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 qemu-devel qemu-devel/ https://lore.kernel.org/qemu-devel \
		qemu-devel@nongnu.org
	public-inbox-index qemu-devel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.nongnu.qemu-devel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git