From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: "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>,
"Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>,
"Rob Herring" <robh@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Alexey Malahov" <Alexey.Malahov@baikalelectronics.ru>,
"Pavel Parkhomenko" <Pavel.Parkhomenko@baikalelectronics.ru>,
linux-pci@vger.kernel.org, dmaengine@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 25/25] PCI: dwc: Add DW eDMA engine support
Date: Mon, 25 Apr 2022 10:52:36 +0530 [thread overview]
Message-ID: <20220425052236.GA5587@thinkpad> (raw)
In-Reply-To: <20220423144055.GR374560@thinkpad>
On Sat, Apr 23, 2022 at 08:10:55PM +0530, Manivannan Sadhasivam wrote:
> On Tue, Apr 19, 2022 at 11:54:03PM +0300, Serge Semin wrote:
> > On Mon, Mar 28, 2022 at 07:45:21PM +0530, Manivannan Sadhasivam wrote:
> > > On Thu, Mar 24, 2022 at 04:48:36AM +0300, Serge Semin wrote:
> > > > Since the DW eDMA driver now supports eDMA controllers embedded into the
> > > > locally accessible DW PCIe Root Ports and End-points, we can use the
> > > > updated interface to register DW eDMA as DMA engine device if it's
> > > > available. In order to successfully do that the DW PCIe core driver need
> > > > to perform some preparations first. First of all it needs to find out the
> > > > eDMA controller CSRs base address, whether they are accessible over the
> > > > Port Logic or iATU unrolled space. Afterwards it can try to auto-detect
> > > > the eDMA controller availability and number of it's read/write channels.
> > > > If none was found the procedure will just silently halt with no error
> > > > returned. Secondly the platform is supposed to provide either combined or
> > > > per-channel IRQ signals. If no valid IRQs set is found the procedure will
> > > > also halt with no error returned so to be backward compatible with
> > > > platforms where DW PCIe controllers have eDMA embedded but lack of the
> > > > IRQs defined for them. Finally before actually probing the eDMA device we
> > > > need to allocate LLP items buffers. After that the DW eDMA can be
> > > > registered. If registration is successful the info-message regarding the
> > > > number of detected Read/Write eDMA channels will be printed to the system
> > > > log in the same way as it's done for iATU settings.
> > > >
> > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > > ---
> > > > .../pci/controller/dwc/pcie-designware-ep.c | 4 +
> > > > .../pci/controller/dwc/pcie-designware-host.c | 13 +-
> > > > drivers/pci/controller/dwc/pcie-designware.c | 188 ++++++++++++++++++
> > > > drivers/pci/controller/dwc/pcie-designware.h | 23 ++-
> > > > 4 files changed, 225 insertions(+), 3 deletions(-)
> > > >
[...]
> > > > diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> > > > index 4a95a7b112e9..dbe39a7ecb71 100644
> > > > --- a/drivers/pci/controller/dwc/pcie-designware.c
> > > > +++ b/drivers/pci/controller/dwc/pcie-designware.c
[...]
> > > Should we introduce a new Kconfig option for enabling eDMA? My concern here is,
> > > if eDMA is really needed for an usecase and if the platform support is broken
> > > somehow (DT issues?), then we'll just simply go ahead without probe failure and
> > > it may break somewhere else.
> > >
> > > And we are returning errors if something wrong happens during eDMA probe. This
> > > might annoy the existing users who don't care about eDMA but turning those
> > > errors to debug will affect the real users of eDMA.
> > >
> > > For these reasons, I think it'd be better to probe eDMA only if the Kconfig
> > > option is enabled (which would be disabled by default). And properly return the
> > > failure.
> >
> > I don't see a need in introducing of a new parametrization. Neither
> > there is a point in dropping the eDMA support on all the platforms for
> > the sake of some hypothetically malfunction hardware.
>
> I'm not talking about "hypothetically malfunction hardware" but real customized
> ones like all Qcom platforms supporting PCIe.
Correction: It is not "all Qcom platforms" but some like SM8250, SM8450 etc...
Thanks,
Mani
next prev parent reply other threads:[~2022-04-25 5:22 UTC|newest]
Thread overview: 79+ 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 11:30 ` Robin Murphy
2022-04-17 22:44 ` Serge Semin
2022-04-20 7:12 ` Christoph Hellwig
2022-04-20 8:32 ` Serge Semin
2022-04-20 8:47 ` Christoph Hellwig
2022-04-20 8:55 ` Serge Semin
2022-04-21 14:45 ` Christoph Hellwig
2022-04-21 17:35 ` Serge Semin
2022-04-21 20:51 ` Robin Murphy
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 [this message]
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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