From: Frank Li <frank.li@nxp.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: "Shunsuke Mie" <mie@igel.co.jp>, "Jon Mason" <jdmason@kudzu.us>,
"Dave Jiang" <dave.jiang@intel.com>,
"Allen Hubbe" <allenbh@gmail.com>,
"kishon@kernel.org" <kishon@kernel.org>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Krzysztof Wilczyński" <kw@linux.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"ntb@lists.linux.dev" <ntb@lists.linux.dev>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [EXT] Re: [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a check for no epc alignment constraint
Date: Thu, 27 Oct 2022 16:25:01 +0000 [thread overview]
Message-ID: <HE1PR0401MB2331032AECAE30A8C31AF01A88339@HE1PR0401MB2331.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <20221027160932.GD76627@thinkpad>
> -----Original Message-----
> From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> Sent: Thursday, October 27, 2022 11:10 AM
> To: Frank Li <frank.li@nxp.com>
> Cc: Shunsuke Mie <mie@igel.co.jp>; Jon Mason <jdmason@kudzu.us>; Dave
> Jiang <dave.jiang@intel.com>; Allen Hubbe <allenbh@gmail.com>;
> kishon@kernel.org; Lorenzo Pieralisi <lpieralisi@kernel.org>; Krzysztof
> Wilczyński <kw@linux.com>; Bjorn Helgaas <bhelgaas@google.com>;
> ntb@lists.linux.dev; linux-pci@vger.kernel.org; linux-kernel@vger.kernel.org
> Subject: Re: [EXT] Re: [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a check for
> no epc alignment constraint
>
> Caution: EXT Email
>
> [Added Kishon's new email address and removed the old one]
>
> On Thu, Oct 27, 2022 at 03:34:11PM +0000, Frank Li wrote:
> >
> >
> > > -----Original Message-----
> > > From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Sent: Thursday, October 27, 2022 10:12 AM
> > > To: Frank Li <frank.li@nxp.com>
> > > Cc: Shunsuke Mie <mie@igel.co.jp>; Jon Mason <jdmason@kudzu.us>;
> Dave
> > > Jiang <dave.jiang@intel.com>; Allen Hubbe <allenbh@gmail.com>;
> Kishon
> > > Vijay Abraham I <kishon@ti.com>; Lorenzo Pieralisi
> <lpieralisi@kernel.org>;
> > > Krzysztof Wilczyński <kw@linux.com>; Bjorn Helgaas
> > > <bhelgaas@google.com>; ntb@lists.linux.dev; linux-pci@vger.kernel.org;
> > > linux-kernel@vger.kernel.org
> > > Subject: Re: [EXT] Re: [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a check
> for
> > > no epc alignment constraint
> > >
> > > Caution: EXT Email
> > >
> > > On Thu, Oct 27, 2022 at 02:35:56PM +0000, Frank Li wrote:
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Shunsuke Mie <mie@igel.co.jp>
> > > > > Sent: Wednesday, October 26, 2022 8:43 PM
> > > > > To: Frank Li <frank.li@nxp.com>
> > > > > Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>;
> Jon
> > > > > Mason <jdmason@kudzu.us>; Dave Jiang <dave.jiang@intel.com>;
> Allen
> > > > > Hubbe <allenbh@gmail.com>; Kishon Vijay Abraham I
> <kishon@ti.com>;
> > > > > Lorenzo Pieralisi <lpieralisi@kernel.org>; Krzysztof Wilczyński
> > > > > <kw@linux.com>; Bjorn Helgaas <bhelgaas@google.com>;
> > > > > ntb@lists.linux.dev; linux-pci@vger.kernel.org; linux-
> > > kernel@vger.kernel.org
> > > > > Subject: Re: [EXT] Re: [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a
> check
> > > for
> > > > > no epc alignment constraint
> > > > >
> > > > > Caution: EXT Email
> > > > >
> > > > > Hi Frank,
> > > > >
> > > > > 2022年10月26日(水) 1:07 Frank Li <frank.li@nxp.com>:
> > > > > >
> > > > > >
> > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Manivannan Sadhasivam
> <manivannan.sadhasivam@linaro.org>
> > > > > > > Sent: Tuesday, October 25, 2022 9:22 AM
> > > > > > > To: Shunsuke Mie <mie@igel.co.jp>
> > > > > > > Cc: Jon Mason <jdmason@kudzu.us>; Dave Jiang
> > > <dave.jiang@intel.com>;
> > > > > > > Allen Hubbe <allenbh@gmail.com>; Kishon Vijay Abraham I
> > > > > > > <kishon@ti.com>; Lorenzo Pieralisi <lpieralisi@kernel.org>;
> Krzysztof
> > > > > > > Wilczyński <kw@linux.com>; Bjorn Helgaas
> <bhelgaas@google.com>;
> > > > > > > ntb@lists.linux.dev; linux-pci@vger.kernel.org; linux-
> > > > > kernel@vger.kernel.org
> > > > > > > Subject: [EXT] Re: [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a
> check
> > > for
> > > > > no
> > > > > > > epc alignment constraint
> > > > > > >
> > > > > > > Caution: EXT Email
> > > > > > >
> > > > > > > On Thu, Sep 22, 2022 at 06:23:57PM +0900, Shunsuke Mie wrote:
> > > > > > > > Some PCI endpoint controllers have no alignment constraints,
> and
> > > the
> > > > > > > > epc_features->align becomes 0. In this case, IS_ALIGNED() in
> > > > > >
> > > > > > [Frank Li] why not set epc_features->align 1
> > > > > > no alignment constraints should mean align to byte.
> > > > > It is one of the solutions too I think. But in that case, we need to
> > > > > write epc_features->align = 1 to all epc drivers, dwc, qcom, rcar,
> > > > > tegra, and etc.
> > > > >
> > > > > I think that my change is better.
> > > >
> > > > I think it should be based on what original term defined.
> > > > It should be fixed at where make mistake.
> > > >
> > >
> > > 1byte is the default alignment that drivers can assume, why do you want
> > > drivers
> > > to set them explicitly when they do not want any special alignment?
> >
> > What's definition of not alignment by align variable?
> > Using both 0 and 1 as no alignment is not good enough.
> >
> > I grep whole kernel driver directory, not one use
> > If (align && IS_ALIGNED(x, align)) statement.
>
> I can see multiple hits:
>
> lib/ubsan.c
> drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> drivers/gpu/drm/i915/i915_vma.c
> drivers/nvdimm/pfn_devs.c
> drivers/misc/pci_endpoint_test.c
>
> But in most of the places, the alignment is guaranteed to be set by the client
> drivers because they might be read from the hardware register or fixed for
> an
> IP. But in this case, I don't think we should _force_ the drivers to set
> alignment to 1 (default) if they don't really care about it.
I keep my opinion. I think EP controller have not reported correct data.
Hardware register also can be set 0 as no alignment means.
It broken "align" conversion.
If most people prefer this way, I suggest change api document at
Include/linux/pci-epc.h to explicitly said 0 is validate option.
>
> Thanks,
> Mani
>
> >
> > There are a common convention, align is 2^n
> >
> >
> > >
> > > I think this patch is fine.
> > >
> > > Thanks,
> > > Mani
> > >
> > > > Are there other place use align == 0 means no alignment in kernel?
> > > >
> > > > >
> > > > > > > > epf_ntb_config_spad_bar_alloc() doesn't work well. Check for
> this
> > > > > before
> > > > > > > > IS_ALIGNED().
> > > > > > > >
> > > > > > > > Signed-off-by: Shunsuke Mie <mie@igel.co.jp>
> > > > > > >
> > > > > > > Reviewed-by: Manivannan Sadhasivam
> > > > > > > <manivannan.sadhasivam@linaro.org>
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Mani
> > > > > > >
> > > > > > > > ---
> > > > > > > > Changes in v2:
> > > > > > > > * Fix the commit message in phrasings and words.
> > > > > > > > ---
> > > > > > > > ---
> > > > > > > > drivers/pci/endpoint/functions/pci-epf-ntb.c | 2 +-
> > > > > > > > drivers/pci/endpoint/functions/pci-epf-vntb.c | 2 +-
> > > > > > > > 2 files changed, 2 insertions(+), 2 deletions(-)
> > > > > > > >
> > > > > > > > diff --git a/drivers/pci/endpoint/functions/pci-epf-ntb.c
> > > > > > > b/drivers/pci/endpoint/functions/pci-epf-ntb.c
> > > > > > > > index 9a00448c7e61..f74155ee8d72 100644
> > > > > > > > --- a/drivers/pci/endpoint/functions/pci-epf-ntb.c
> > > > > > > > +++ b/drivers/pci/endpoint/functions/pci-epf-ntb.c
> > > > > > > > @@ -1021,7 +1021,7 @@ static int
> > > > > epf_ntb_config_spad_bar_alloc(struct
> > > > > > > epf_ntb *ntb,
> > > > > > > > peer_size = peer_epc_features->bar_fixed_size[peer_barno];
> > > > > > > >
> > > > > > > > /* Check if epc_features is populated incorrectly */
> > > > > > > > - if ((!IS_ALIGNED(size, align)))
> > > > > > > > + if (align && (!IS_ALIGNED(size, align)))
> > > > > > > > return -EINVAL;
> > > > > > > >
> > > > > > > > spad_count = ntb->spad_count;
> > > > > > > > diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c
> > > > > > > b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> > > > > > > > index 0ea85e1d292e..5e346c0a0f05 100644
> > > > > > > > --- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
> > > > > > > > +++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
> > > > > > > > @@ -418,7 +418,7 @@ static int
> > > epf_ntb_config_spad_bar_alloc(struct
> > > > > > > epf_ntb *ntb)
> > > > > > > > size = epc_features->bar_fixed_size[barno];
> > > > > > > > align = epc_features->align;
> > > > > > > >
> > > > > > > > - if ((!IS_ALIGNED(size, align)))
> > > > > > > > + if (align && !IS_ALIGNED(size, align))
> > > > > > > > return -EINVAL;
> > > > > > > >
> > > > > > > > spad_count = ntb->spad_count;
> > > > > > > > --
> > > > > > > > 2.17.1
> > > > > > > >
> > > > > > >
> > > > > > > --
> > > > > > > மணிவண்ணன் சதாசிவம்
> > > > >
> > > > > Best,
> > > > > Shunsuke
> > >
> > > --
> > > மணிவண்ணன் சதாசிவம்
>
> --
> மணிவண்ணன் சதாசிவம்
next prev parent reply other threads:[~2022-10-27 16:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-22 9:23 [PATCH v2] PCI: endpoint: pci-epf-{,v}ntb: fix a check for no epc alignment constraint Shunsuke Mie
2022-10-25 14:21 ` Manivannan Sadhasivam
2022-10-25 16:07 ` [EXT] " Frank Li
2022-10-27 1:43 ` Shunsuke Mie
2022-10-27 14:35 ` Frank Li
2022-10-27 15:12 ` Manivannan Sadhasivam
2022-10-27 15:34 ` Frank Li
2022-10-27 16:09 ` Manivannan Sadhasivam
2022-10-27 16:25 ` Frank Li [this message]
2022-10-28 10:56 ` Shunsuke Mie
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