From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: James Hilliard <james.hilliard1@gmail.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>,
Vinod Koul <vkoul@kernel.org>, Frank Li <Frank.Li@kernel.org>,
Sergey Khimich <serghox@gmail.com>,
Sia Jee Heng <jee.heng.sia@intel.com>,
dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH 1/3] dmaengine: dw-axi-dmac: poll the correct enable bit during termination
Date: Tue, 10 Nov 2026 00:49:51 +0200 [thread overview]
Message-ID: <avJOD_jpXRpvspY1@ashevche-desk.local> (raw)
In-Reply-To: <20261108-submit-dw-axi-dma-stop-pause-v1-v1-1-c48ec19e9ee4@gmail.com>
On Sun, Nov 08, 2026 at 10:02:36PM -0700, James Hilliard wrote:
> For channels 16 through 31, the channel enable bits occupy bits 32 through
> 47 of the extended DMAC_CHEN register. dma_chan_terminate_all() only reads
> the low word and tests BIT(chan->id), so it can conclude that an upper-bank
> channel has stopped while its actual enable bit remains set. Descriptors
> can then be freed while hardware still owns them.
>
> Poll axi_chan_is_hw_enable(), which already handles both register banks
> and the smaller channel layouts, instead of constructing another mask.
...
> - ret = readl_poll_timeout_atomic(chan->chip->regs + DMAC_CHEN, val,
> - !(val & chan_active), 1000, 50000);
> + ret = read_poll_timeout_atomic(axi_chan_is_hw_enable, enabled, !enabled,
> + 1000, 50000, false, chan);
With a single argument it's readx_poll_timeout_atomic().
While at it, you may use 1 * USEC_PER_MSEC and 50 * USEC_PER_MSEC instead of
plain numbers.
ret = readx_poll_timeout_atomic(axi_chan_is_hw_enable, chan,
enabled, !enabled,
1 * USEC_PER_MSEC, 50 * USEC_PER_MSEC);
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-11-09 22:49 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-09 5:02 [PATCH 0/3] dmaengine: dw-axi-dmac: fix termination and pause acknowledgment James Hilliard
2026-11-09 5:02 ` [PATCH 1/3] dmaengine: dw-axi-dmac: poll the correct enable bit during termination James Hilliard
2026-11-09 22:49 ` Andy Shevchenko [this message]
2026-11-09 5:02 ` [PATCH 2/3] dmaengine: dw-axi-dmac: retain descriptors when termination times out James Hilliard
2026-11-09 5:02 ` [PATCH 3/3] dmaengine: dw-axi-dmac: preserve suspension status until pause observes it James Hilliard
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