From: Tudor Ambarus <tudor.ambarus@microchip.com>
To: <vkoul@kernel.org>, <peda@axentia.se>, <du@axentia.se>
Cc: <maciej.sosnowski@intel.com>, <nicolas.ferre@microchip.com>,
<mripard@kernel.org>, <torfl6749@gmail.com>,
<linux-kernel@vger.kernel.org>, <dmaengine@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
"Tudor Ambarus" <tudor.ambarus@microchip.com>,
<stable@vger.kernel.org>
Subject: [PATCH v2 13/32] dmaengine: at_hdmac: Don't allow CPU to reorder channel enable
Date: Tue, 25 Oct 2022 12:02:47 +0300 [thread overview]
Message-ID: <20221025090306.297886-14-tudor.ambarus@microchip.com> (raw)
In-Reply-To: <20221025090306.297886-1-tudor.ambarus@microchip.com>
at_hdmac uses __raw_writel for register writes. In the absence of a
barrier, the CPU may reorder the register operations.
Introduce a write memory barrier so that the CPU does not reorder the
channel enable, thus the start of the transfer, without making sure that
all the pre-required register fields are already written.
Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller")
Reported-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/
---
drivers/dma/at_hdmac.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index 80eeb4fb88ef..968a5aba47cd 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -256,6 +256,8 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
ATC_SPIP_BOUNDARY(first->boundary));
channel_writel(atchan, DPIP, ATC_DPIP_HOLE(first->dst_hole) |
ATC_DPIP_BOUNDARY(first->boundary));
+ /* Don't allow CPU to reorder channel enable. */
+ wmb();
dma_writel(atdma, CHER, atchan->mask);
vdbg_dump_regs(atchan);
--
2.25.1
next prev parent reply other threads:[~2022-10-25 9:05 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-25 9:02 [PATCH v2 00/32] dmaengine: at_hdmac: Fix concurrency bugs and then convert to virt-dma Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 01/32] dmaengine: at_hdmac: Fix at_lli struct definition Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 02/32] dmaengine: at_hdmac: Don't start transactions at tx_submit level Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 03/32] dmaengine: at_hdmac: Start transfer for cyclic channels in issue_pending Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 04/32] dmaengine: at_hdmac: Fix premature completion of desc " Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 05/32] dmaengine: at_hdmac: Do not call the complete callback on device_terminate_all Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 06/32] dmaengine: at_hdmac: Protect atchan->status with the channel lock Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 07/32] dmaengine: at_hdmac: Fix concurrency problems by removing atc_complete_all() Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 08/32] dmaengine: at_hdmac: Fix concurrency over descriptor Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 09/32] dmaengine: at_hdmac: Free the memset buf without holding the chan lock Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 10/32] dmaengine: at_hdmac: Fix concurrency over the active list Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 11/32] dmaengine: at_hdmac: Fix descriptor handling when issuing it to hardware Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 12/32] dmaengine: at_hdmac: Fix completion of unissued descriptor in case of errors Tudor Ambarus
2022-10-25 9:02 ` Tudor Ambarus [this message]
2022-10-25 9:02 ` [PATCH v2 14/32] dmaengine: at_hdmac: Fix impossible condition Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 15/32] dmaengine: at_hdmac: Check return code of dma_async_device_register Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 16/32] dmaengine: at_hdmac: Do not print messages on console while holding the lock Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 17/32] dmaengine: at_hdmac: Return dma_cookie_status()'s ret code when txstate is NULL Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 18/32] dmaengine: at_hdmac: Remove superfluous cast Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 19/32] dmaengine: at_hdmac: Pass residue by address to avoid unnecessary implicit casts Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 20/32] dmaengine: at_hdmac: s/atc_get_bytes_left/atc_get_residue Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 21/32] dmaengine: at_hdmac: Introduce atc_get_llis_residue() Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 22/32] dmaengine: at_hdmac: Use devm_kzalloc() and struct_size() Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 23/32] dmaengine: at_hdmac: Use devm_platform_ioremap_resource Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 24/32] dmaengine: at_hdmac: Use devm_clk_get() Tudor Ambarus
2022-10-25 9:02 ` [PATCH v2 25/32] dmaengine: at_hdmac: Use pm_ptr() Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 26/32] dmaengine: at_hdmac: Set include entries in alphabetic order Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 27/32] dmaengine: at_hdmac: Keep register definitions and structures private to at_hdmac.c Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 28/32] dmaengine: at_hdmac: Use bitfield access macros Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 29/32] dmaengine: at_hdmac: Rename "dma_common" to "dma_device" Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 30/32] dmaengine: at_hdmac: Rename "chan_common" to "dma_chan" Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 31/32] dmaengine: at_hdmac: Remove unused member of at_dma_chan Tudor Ambarus
2022-10-25 9:03 ` [PATCH v2 32/32] dmaengine: at_hdmac: Convert driver to use virt-dma Tudor Ambarus
2022-10-28 12:55 ` Nicolas Ferre
2022-10-25 9:06 ` [PATCH v2 00/32] dmaengine: at_hdmac: Fix concurrency bugs and then convert to virt-dma Tudor.Ambarus
2022-10-28 13:00 ` Nicolas Ferre
2022-11-04 13:22 ` Vinod Koul
2022-11-04 15:14 ` Tudor.Ambarus
2022-11-04 15:21 ` Tudor.Ambarus
2022-11-04 17:59 ` Vinod Koul
2022-11-07 4:33 ` Vinod Koul
2022-11-07 9:00 ` Tudor.Ambarus
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