From: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
To: Marek Szyprowski <m.szyprowski@samsung.com>,
Leon Romanovsky <leon@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Russell King <linux@armlinux.org.uk>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
Richard Henderson <richard.henderson@linaro.org>,
Matt Turner <mattst88@gmail.com>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Helge Deller <deller@gmx.de>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>,
Geoff Levand <geoff@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
Andreas Larsson <andreas@gaisler.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
xen-devel@lists.xenproject.org, linux-alpha@vger.kernel.org,
linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org,
sparclinux <sparclinux@vger.kernel.org>
Subject: Re: [PATCH v5 11/14] sparc: Use physical address DMA mapping
Date: Tue, 17 Feb 2026 14:57:31 +0100 [thread overview]
Message-ID: <8317613a286ab637ac29740433ff51286ebbbaca.camel@physik.fu-berlin.de> (raw)
In-Reply-To: <7131d609-b083-4264-818a-21de38c1c3ed@samsung.com>
Hi Marek,
On Tue, 2026-02-17 at 13:55 +0100, Marek Szyprowski wrote:
> On 17.02.2026 13:27, John Paul Adrian Glaubitz wrote:
> > On Wed, 2025-10-15 at 12:12 +0300, Leon Romanovsky wrote:
> > > From: Leon Romanovsky <leonro@nvidia.com>
> > >
> > > Convert sparc architecture DMA code to use .map_phys callback.
> > >
> > > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > > ---
> > > arch/sparc/kernel/iommu.c | 30 +++++++++++++++++-----------
> > > arch/sparc/kernel/pci_sun4v.c | 31 ++++++++++++++++++-----------
> > > arch/sparc/mm/io-unit.c | 38 ++++++++++++++++++-----------------
> > > arch/sparc/mm/iommu.c | 46 ++++++++++++++++++++++---------------------
> > > 4 files changed, 82 insertions(+), 63 deletions(-)
> > >
> > > diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
> > > index da0363692528..46ef88bc9c26 100644
> > > --- a/arch/sparc/kernel/iommu.c
> > > +++ b/arch/sparc/kernel/iommu.c
> > > @@ -260,26 +260,35 @@ static void dma_4u_free_coherent(struct device *dev, size_t size,
> > > free_pages((unsigned long)cpu, order);
> > > }
> > >
> > > -static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
> > > - unsigned long offset, size_t sz,
> > > - enum dma_data_direction direction,
> > > +static dma_addr_t dma_4u_map_phys(struct device *dev, phys_addr_t phys,
> > > + size_t sz, enum dma_data_direction direction,
> > > unsigned long attrs)
> > > {
> > > struct iommu *iommu;
> > > struct strbuf *strbuf;
> > > iopte_t *base;
> > > unsigned long flags, npages, oaddr;
> > > - unsigned long i, base_paddr, ctx;
> > > + unsigned long i, ctx;
> > > u32 bus_addr, ret;
> > > unsigned long iopte_protection;
> > >
> > > + if (unlikely(attrs & DMA_ATTR_MMIO))
> > > + /*
> > > + * This check is included because older versions of the code
> > > + * lacked MMIO path support, and my ability to test this path
> > > + * is limited. However, from a software technical standpoint,
> > > + * there is no restriction, as the following code operates
> > > + * solely on physical addresses.
> > > + */
> > > + goto bad_no_ctx;
> > > +
> > > iommu = dev->archdata.iommu;
> > > strbuf = dev->archdata.stc;
> > >
> > > if (unlikely(direction == DMA_NONE))
> > > goto bad_no_ctx;
> > >
> > > - oaddr = (unsigned long)(page_address(page) + offset);
> > > + oaddr = (unsigned long)(phys_to_virt(phys));
> > > npages = IO_PAGE_ALIGN(oaddr + sz) - (oaddr & IO_PAGE_MASK);
> > > npages >>= IO_PAGE_SHIFT;
> > >
> > > @@ -296,7 +305,6 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
> > > bus_addr = (iommu->tbl.table_map_base +
> > > ((base - iommu->page_table) << IO_PAGE_SHIFT));
> > > ret = bus_addr | (oaddr & ~IO_PAGE_MASK);
> > > - base_paddr = __pa(oaddr & IO_PAGE_MASK);
> > > if (strbuf->strbuf_enabled)
> > > iopte_protection = IOPTE_STREAMING(ctx);
> > > else
> > > @@ -304,8 +312,8 @@ static dma_addr_t dma_4u_map_page(struct device *dev, struct page *page,
> > > if (direction != DMA_TO_DEVICE)
> > > iopte_protection |= IOPTE_WRITE;
> > >
> > > - for (i = 0; i < npages; i++, base++, base_paddr += IO_PAGE_SIZE)
> > > - iopte_val(*base) = iopte_protection | base_paddr;
> > > + for (i = 0; i < npages; i++, base++, phys += IO_PAGE_SIZE)
> > > + iopte_val(*base) = iopte_protection | phys;
>
> 'base_paddr' was aligned to start of a page before this patch, while
> 'phys' includes the offset within a page.
>
>
> Could You check if the following change fixes the issue?
>
> diff --git a/arch/sparc/kernel/iommu.c b/arch/sparc/kernel/iommu.c
> index 46ef88bc9c26..edb0ffb21e2f 100644
> --- a/arch/sparc/kernel/iommu.c
> +++ b/arch/sparc/kernel/iommu.c
> @@ -312,6 +312,7 @@ static dma_addr_t dma_4u_map_phys(struct device
> *dev, phys_addr_t phys,
> if (direction != DMA_TO_DEVICE)
> iopte_protection |= IOPTE_WRITE;
>
> + phys -= offset_in_page(phys);
> for (i = 0; i < npages; i++, base++, phys += IO_PAGE_SIZE)
> iopte_val(*base) = iopte_protection | phys;
Thanks, I have forwarded your patch and asked the user to answer here if possible [1].
Adrian
> [1] https://github.com/sparclinux/issues/issues/75#issuecomment-3914791862
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer
`. `' Physicist
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
next prev parent reply other threads:[~2026-02-17 13:57 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20251015091313eucas1p2426ae40b579d7f3b4f29b46e0e788c0d@eucas1p2.samsung.com>
2025-10-15 9:12 ` [PATCH v5 00/14] Remove DMA map_page/map_resource and their unmap callbacks Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 01/14] dma-mapping: prepare dma_map_ops to conversion to physical address Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 02/14] dma-mapping: convert dummy ops to physical address mapping Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 03/14] ARM: dma-mapping: Reduce struct page exposure in arch_sync_dma*() Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 04/14] ARM: dma-mapping: Switch to physical address mapping callbacks Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 05/14] xen: swiotlb: " Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 06/14] dma-mapping: remove unused mapping resource callbacks Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 07/14] alpha: Convert mapping routine to rely on physical address Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 08/14] MIPS/jazzdma: Provide physical address directly Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 09/14] parisc: Convert DMA map_page to map_phys interface Leon Romanovsky
2025-12-17 12:17 ` [PATCH v5 09/14] parisc: Convert DMA map_page to map_phys interface [qemu test failure] Guenter Roeck
2025-12-18 8:40 ` Leon Romanovsky
2025-12-18 12:11 ` Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 10/14] powerpc: Convert to physical address DMA mapping Leon Romanovsky
2025-11-14 9:02 ` Christophe Leroy
2025-10-15 9:12 ` [PATCH v5 11/14] sparc: Use " Leon Romanovsky
2026-02-17 12:27 ` John Paul Adrian Glaubitz
2026-02-17 12:55 ` Marek Szyprowski
2026-02-17 13:15 ` Leon Romanovsky
2026-02-17 13:57 ` John Paul Adrian Glaubitz [this message]
2025-10-15 9:12 ` [PATCH v5 12/14] x86: Use physical address for " Leon Romanovsky
2025-10-15 9:12 ` [PATCH v5 13/14] xen: swiotlb: Convert mapping routine to rely on physical address Leon Romanovsky
2025-10-15 9:13 ` [PATCH v5 14/14] dma-mapping: remove unused map_page callback Leon Romanovsky
2025-10-20 16:27 ` [PATCH v5 00/14] Remove DMA map_page/map_resource and their unmap callbacks Marek Szyprowski
2025-10-26 7:38 ` Leon Romanovsky
2025-10-29 10:00 ` Marek Szyprowski
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