From: Christoph Hellwig <hch@lst.de>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: "Robin Murphy" <robin.murphy@arm.com>,
"Serge Semin" <Sergey.Semin@baikalelectronics.ru>,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
"Vinod Koul" <vkoul@kernel.org>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Frank Li" <Frank.Li@nxp.com>,
"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
"Christoph Hellwig" <hch@lst.de>,
"Marek Szyprowski" <m.szyprowski@samsung.com>,
"Vladimir Murzin" <vladimir.murzin@arm.com>,
"Alexey Malahov" <Alexey.Malahov@baikalelectronics.ru>,
"Pavel Parkhomenko" <Pavel.Parkhomenko@baikalelectronics.ru>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
linux-pci@vger.kernel.org, dmaengine@vger.kernel.org,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org
Subject: Re: [PATCH 03/25] dma-direct: take dma-ranges/offsets into account in resource mapping
Date: Wed, 20 Apr 2022 09:12:17 +0200 [thread overview]
Message-ID: <20220420071217.GA5152@lst.de> (raw)
In-Reply-To: <20220417224427.drwy3rchwplthelh@mobilestation>
On Mon, Apr 18, 2022 at 01:44:27AM +0300, Serge Semin wrote:
> > but a DMA controller might also want to access something in the MMIO range
> > 0x0-0x7fffffff, of which it still has an identical non-offset view. If a
> > driver was previously using dma_map_resource() for that, it would now start
> > getting DMA_MAPPING_ERROR because the dma_range_map exists but doesn't
> > describe the MMIO region. I agree that in hindsight it's not an ideal
> > situation, but it's how things have ended up, so at this point I'm wary of
> > making potentially-breaking changes.
>
> Hmm, what if the driver was previously using for instance the
> dma_direct_map_sg() method for it?
dma_map_resource is for mapping MMIO space, and must not be called on
memory in the kernel map. For dma_map_sg (or all the other dma_map_*
interface except for dma_map_resource), the reverse is true.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: "Rob Herring" <robh@kernel.org>,
"Vladimir Murzin" <vladimir.murzin@arm.com>,
"Krzysztof Wilczyński" <kw@linux.com>,
linux-pci@vger.kernel.org,
"Gustavo Pimentel" <gustavo.pimentel@synopsys.com>,
"Manivannan Sadhasivam" <manivannan.sadhasivam@linaro.org>,
"Frank Li" <Frank.Li@nxp.com>,
linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
"Alexey Malahov" <Alexey.Malahov@baikalelectronics.ru>,
"Serge Semin" <Sergey.Semin@baikalelectronics.ru>,
dmaengine@vger.kernel.org, "Vinod Koul" <vkoul@kernel.org>,
"Pavel Parkhomenko" <Pavel.Parkhomenko@baikalelectronics.ru>,
"Jingoo Han" <jingoohan1@gmail.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Robin Murphy" <robin.murphy@arm.com>,
"Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH 03/25] dma-direct: take dma-ranges/offsets into account in resource mapping
Date: Wed, 20 Apr 2022 09:12:17 +0200 [thread overview]
Message-ID: <20220420071217.GA5152@lst.de> (raw)
In-Reply-To: <20220417224427.drwy3rchwplthelh@mobilestation>
On Mon, Apr 18, 2022 at 01:44:27AM +0300, Serge Semin wrote:
> > but a DMA controller might also want to access something in the MMIO range
> > 0x0-0x7fffffff, of which it still has an identical non-offset view. If a
> > driver was previously using dma_map_resource() for that, it would now start
> > getting DMA_MAPPING_ERROR because the dma_range_map exists but doesn't
> > describe the MMIO region. I agree that in hindsight it's not an ideal
> > situation, but it's how things have ended up, so at this point I'm wary of
> > making potentially-breaking changes.
>
> Hmm, what if the driver was previously using for instance the
> dma_direct_map_sg() method for it?
dma_map_resource is for mapping MMIO space, and must not be called on
memory in the kernel map. For dma_map_sg (or all the other dma_map_*
interface except for dma_map_resource), the reverse is true.
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next prev parent reply other threads:[~2022-04-20 7:12 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-24 1:48 [PATCH 00/25] dmaengine: dw-edma: Add RP/EP local DMA controllers support Serge Semin
2022-03-24 1:48 ` [PATCH 01/25] dmaengine: dw-edma: Drop dma_slave_config.direction field usage Serge Semin
2022-03-24 13:30 ` Manivannan Sadhasivam
2022-04-05 11:15 ` Serge Semin
2022-03-24 1:48 ` [PATCH 02/25] dmaengine: dw-edma: Fix eDMA Rd/Wr-channels and DMA-direction semantics Serge Semin
2022-03-24 1:48 ` [PATCH 03/25] dma-direct: take dma-ranges/offsets into account in resource mapping Serge Semin
2022-03-24 1:48 ` Serge Semin
2022-03-24 11:30 ` Robin Murphy
2022-03-24 11:30 ` Robin Murphy
2022-04-17 22:44 ` Serge Semin
2022-04-17 22:44 ` Serge Semin
2022-04-20 7:12 ` Christoph Hellwig [this message]
2022-04-20 7:12 ` Christoph Hellwig
2022-04-20 8:32 ` Serge Semin
2022-04-20 8:32 ` Serge Semin
2022-04-20 8:47 ` Christoph Hellwig
2022-04-20 8:47 ` Christoph Hellwig
2022-04-20 8:55 ` Serge Semin
2022-04-20 8:55 ` Serge Semin
2022-04-21 14:45 ` Christoph Hellwig
2022-04-21 14:45 ` Christoph Hellwig
2022-04-21 17:35 ` Serge Semin
2022-04-21 17:35 ` Serge Semin
2022-04-21 20:51 ` Robin Murphy
2022-04-21 20:51 ` Robin Murphy
2022-04-24 21:46 ` Serge Semin
2022-04-24 21:46 ` Serge Semin
2022-03-24 1:48 ` [PATCH 04/25] dmaengine: Fix dma_slave_config.dst_addr description Serge Semin
2022-03-24 14:08 ` Manivannan Sadhasivam
2022-03-31 5:38 ` Vinod Koul
2022-03-31 7:13 ` Serge Semin
2022-03-31 10:50 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 05/25] dmaengine: dw-edma: Convert ll/dt phys-address to PCIe bus/DMA address Serge Semin
2022-03-24 16:23 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 06/25] dmaengine: dw-edma: Fix missing src/dst address of the interleaved xfers Serge Semin
2022-03-24 16:26 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 07/25] dmaengine: dw-edma: Don't permit non-inc " Serge Semin
2022-03-24 17:15 ` Manivannan Sadhasivam
2022-04-17 22:59 ` Serge Semin
2022-03-24 1:48 ` [PATCH 08/25] dmaengine: dw-edma: Fix invalid interleaved xfers semantics Serge Semin
2022-03-24 1:48 ` [PATCH 09/25] dmaengine: dw-edma: Add CPU to PCIe bus address translation Serge Semin
2022-03-24 17:25 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 10/25] dmaengine: dw-edma: Add PCIe bus address getter to the remote EP glue-driver Serge Semin
2022-03-24 17:41 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 11/25] dmaengine: dw-edma: Drop chancnt initialization Serge Semin
2022-03-24 17:42 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 12/25] dmaengine: dw-edma: Fix DebugFS reg entry type Serge Semin
2022-03-24 17:48 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 13/25] dmaengine: dw-edma: Stop checking debugfs_create_*() return value Serge Semin
2022-03-24 18:12 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 14/25] dmaengine: dw-edma: Add dw_edma prefix to the DebugFS nodes descriptor Serge Semin
2022-03-24 18:14 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 15/25] dmaengine: dw-edma: Convert DebugFS descs to being kz-allocated Serge Semin
2022-03-25 6:03 ` Manivannan Sadhasivam
2022-03-25 6:42 ` Manivannan Sadhasivam
2022-04-18 7:17 ` Serge Semin
2022-03-24 1:48 ` [PATCH 16/25] dmaengine: dw-edma: Simplify the DebugFS context CSRs init procedure Serge Semin
2022-03-25 6:27 ` Manivannan Sadhasivam
2022-03-25 6:31 ` Manivannan Sadhasivam
2022-04-18 8:23 ` Serge Semin
2022-03-24 1:48 ` [PATCH 17/25] dmaengine: dw-edma: Move eDMA data pointer to DebugFS node descriptor Serge Semin
2022-03-25 6:35 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 18/25] dmaengine: dw-edma: Join Write/Read channels into a single device Serge Semin
2022-03-25 7:34 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 19/25] dmaengine: dw-edma: Use DMA-engine device DebugFS subdirectory Serge Semin
2022-03-25 7:41 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 20/25] dmaengine: dw-edma: Use non-atomic io-64 methods Serge Semin
2022-03-25 8:28 ` Manivannan Sadhasivam
2022-04-18 11:37 ` Serge Semin
2022-03-24 1:48 ` [PATCH 21/25] dmaengine: dw-edma: Drop DT-region allocation Serge Semin
2022-03-25 8:33 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 22/25] dmaengine: dw-edma: Replace chip ID number with device name Serge Semin
2022-03-25 10:02 ` Manivannan Sadhasivam
2022-04-18 12:17 ` Serge Semin
2022-03-24 1:48 ` [PATCH 23/25] dmaengine: dw-edma: Bypass dma-ranges mapping for the local setup Serge Semin
2022-03-25 18:10 ` Manivannan Sadhasivam
2022-04-18 13:36 ` Serge Semin
2022-03-24 1:48 ` [PATCH 24/25] dmaengine: dw-edma: Skip cleanup procedure if no private data found Serge Semin
2022-03-25 18:15 ` Manivannan Sadhasivam
2022-04-18 13:48 ` Serge Semin
2022-04-23 14:45 ` Manivannan Sadhasivam
2022-03-24 1:48 ` [PATCH 25/25] PCI: dwc: Add DW eDMA engine support Serge Semin
2022-03-28 14:15 ` Manivannan Sadhasivam
2022-04-19 20:54 ` Serge Semin
2022-04-23 14:40 ` Manivannan Sadhasivam
2022-04-25 5:22 ` Manivannan Sadhasivam
2022-04-28 14:05 ` Serge Semin
2022-04-28 17:09 ` Manivannan Sadhasivam
2022-04-29 16:13 ` Serge Semin
2022-04-29 17:20 ` Manivannan Sadhasivam
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