From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Hector Martin" <marcan@marcan.st>,
"Martin Povišer" <povik+lin@cutebit.org>,
"Vinod Koul" <vkoul@kernel.org>,
"Sasha Levin" <sashal@kernel.org>,
sven@svenpeter.dev, asahi@lists.linux.dev,
linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org
Subject: [PATCH AUTOSEL 6.7 01/12] dmaengine: apple-admac: Keep upper bits of REG_BUS_WIDTH
Date: Mon, 29 Jan 2024 13:34:10 -0500 [thread overview]
Message-ID: <20240129183440.463998-1-sashal@kernel.org> (raw)
From: Hector Martin <marcan@marcan.st>
[ Upstream commit 306f5df81fcc89b462fbeb9dbe26d9a8ad7c7582 ]
For RX channels, REG_BUS_WIDTH seems to default to a value of 0xf00, and
macOS preserves the upper bits when setting the configuration in the
lower ones. If we reset the upper bits to 0, this causes framing errors
on suspend/resume (the data stream "tears" and channels get swapped
around). Keeping the upper bits untouched, like the macOS driver does,
fixes this issue.
Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Martin Povišer <povik+lin@cutebit.org>
Signed-off-by: Martin Povišer <povik+lin@cutebit.org>
Link: https://lore.kernel.org/r/20231029170704.82238-1-povik+lin@cutebit.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/apple-admac.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/apple-admac.c b/drivers/dma/apple-admac.c
index 5b63996640d9..9588773dd2eb 100644
--- a/drivers/dma/apple-admac.c
+++ b/drivers/dma/apple-admac.c
@@ -57,6 +57,8 @@
#define REG_BUS_WIDTH(ch) (0x8040 + (ch) * 0x200)
+#define BUS_WIDTH_WORD_SIZE GENMASK(3, 0)
+#define BUS_WIDTH_FRAME_SIZE GENMASK(7, 4)
#define BUS_WIDTH_8BIT 0x00
#define BUS_WIDTH_16BIT 0x01
#define BUS_WIDTH_32BIT 0x02
@@ -740,7 +742,8 @@ static int admac_device_config(struct dma_chan *chan,
struct admac_data *ad = adchan->host;
bool is_tx = admac_chan_direction(adchan->no) == DMA_MEM_TO_DEV;
int wordsize = 0;
- u32 bus_width = 0;
+ u32 bus_width = readl_relaxed(ad->base + REG_BUS_WIDTH(adchan->no)) &
+ ~(BUS_WIDTH_WORD_SIZE | BUS_WIDTH_FRAME_SIZE);
switch (is_tx ? config->dst_addr_width : config->src_addr_width) {
case DMA_SLAVE_BUSWIDTH_1_BYTE:
--
2.43.0
reply other threads:[~2024-01-29 18:34 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=20240129183440.463998-1-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=asahi@lists.linux.dev \
--cc=dmaengine@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=marcan@marcan.st \
--cc=povik+lin@cutebit.org \
--cc=stable@vger.kernel.org \
--cc=sven@svenpeter.dev \
--cc=vkoul@kernel.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 read-only IMAP folder(s) and NNTP newsgroup(s).