From: Bin Meng <bmeng.cn@gmail.com>
To: Alistair Francis <Alistair.Francis@wdc.com>,
qemu-devel@nongnu.org, qemu-riscv@nongnu.org
Cc: "Frank Chang" <frank.chang@sifive.com>,
"Philippe Mathieu-Daudé" <f4bug@amsat.org>,
"Markus Armbruster" <armbru@redhat.com>
Subject: [PATCH v2 2/2] hw/dma: sifive_pdma: Don't run DMA when channel is disclaimed
Date: Mon, 27 Sep 2021 15:21:24 +0800 [thread overview]
Message-ID: <20210927072124.1564129-2-bmeng.cn@gmail.com> (raw)
In-Reply-To: <20210927072124.1564129-1-bmeng.cn@gmail.com>
If Control.run bit is set while not preserving the Control.claim
bit, the DMA transfer shall not be started.
The following result is PDMA tested in U-Boot on Unleashed board:
=> mw.l 0x3000000 0x0 <= Disclaim channel 0
=> mw.l 0x3000000 0x1 <= Claim channel 0
=> mw.l 0x3000004 0x55000000 <= wsize = rsize = 5 (2^5 = 32 bytes)
=> mw.q 0x3000008 0x2 <= NextBytes = 2
=> mw.q 0x3000010 0x84000000 <= NextDestination = 0x84000000
=> mw.q 0x3000018 0x84001000 <= NextSource = 0x84001000
=> mw.l 0x84000000 0x87654321 <= Fill test data to dst
=> mw.l 0x84001000 0x12345678 <= Fill test data to src
=> md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents
84000000: 87654321 !Ce.
84001000: 12345678 xV4.
=> md.l 0x3000000 8 <= Dump PDMA status
03000000: 00000001 55000000 00000002 00000000 .......U........
03000010: 84000000 00000000 84001000 00000000 ................
=> mw.l 0x3000000 0x2 <= Set channel 0 run bit only
=> md.l 0x3000000 8 <= Dump PDMA status
03000000: 00000000 55000000 00000002 00000000 .......U........
03000010: 84000000 00000000 84001000 00000000 ................
=> md.l 0x84000000 1; md.l 0x84001000 1 <= Dump src/dst memory contents
84000000: 87654321 !Ce.
84001000: 12345678 xV4.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
---
(no changes since v1)
hw/dma/sifive_pdma.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/hw/dma/sifive_pdma.c b/hw/dma/sifive_pdma.c
index b8ec7621f3..85fe34f5f3 100644
--- a/hw/dma/sifive_pdma.c
+++ b/hw/dma/sifive_pdma.c
@@ -232,7 +232,7 @@ static void sifive_pdma_write(void *opaque, hwaddr offset,
{
SiFivePDMAState *s = opaque;
int ch = SIFIVE_PDMA_CHAN_NO(offset);
- bool claimed;
+ bool claimed, run;
if (ch >= SIFIVE_PDMA_CHANS) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: Invalid channel no %d\n",
@@ -244,6 +244,7 @@ static void sifive_pdma_write(void *opaque, hwaddr offset,
switch (offset) {
case DMA_CONTROL:
claimed = !!(s->chan[ch].control & CONTROL_CLAIM);
+ run = !!(s->chan[ch].control & CONTROL_RUN);
if (!claimed && (value & CONTROL_CLAIM)) {
/* reset Next* registers */
@@ -254,13 +255,19 @@ static void sifive_pdma_write(void *opaque, hwaddr offset,
s->chan[ch].next_src = 0;
}
+ /* claim bit can only be cleared when run is low */
+ if (run && !(value & CONTROL_CLAIM)) {
+ value |= CONTROL_CLAIM;
+ }
+
s->chan[ch].control = value;
/*
* If channel was not claimed before run bit is set,
+ * or if the channel is disclaimed when run was low,
* DMA won't run.
*/
- if (!claimed) {
+ if (!claimed || (!run && !(value & CONTROL_CLAIM))) {
s->chan[ch].control &= ~CONTROL_RUN;
return;
}
--
2.25.1
next prev parent reply other threads:[~2021-09-27 7:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-27 7:21 [PATCH v2 1/2] hw/dma: sifive_pdma: Fix Control.claim bit detection Bin Meng
2021-09-27 7:21 ` Bin Meng [this message]
2021-09-28 22:46 ` [PATCH v2 2/2] hw/dma: sifive_pdma: Don't run DMA when channel is disclaimed Alistair Francis
2021-09-28 23:15 ` Alistair Francis
2021-09-27 12:56 ` [PATCH v2 1/2] hw/dma: sifive_pdma: Fix Control.claim bit detection Philippe Mathieu-Daudé
2021-09-27 13:14 ` Bin Meng
2021-09-28 22:45 ` Alistair Francis
Reply instructions:
You may reply publicly 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=20210927072124.1564129-2-bmeng.cn@gmail.com \
--to=bmeng.cn@gmail.com \
--cc=Alistair.Francis@wdc.com \
--cc=armbru@redhat.com \
--cc=f4bug@amsat.org \
--cc=frank.chang@sifive.com \
--cc=qemu-devel@nongnu.org \
--cc=qemu-riscv@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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).