From: Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> To: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org> Cc: Russell King - ARM Linux <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Yehuda Yitschak <yehuday-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Hanna Hawa <hannah-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Nadav Haklai <nadavh-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>, Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>, Gregory Clement <gregory.clement-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>, Stefan Chulski <stefanc-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Marcin Wojtas <mw-nYOzD4b6Jr9Wk0Htik3J/w@public.gmane.org>, "David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Subject: Re: [PATCHv2 net-next 05/16] net: mvpp2: introduce PPv2.2 HW descriptors and adapt accessors Date: Fri, 3 Feb 2017 14:24:46 +0100 [thread overview] Message-ID: <20170203142446.2ee517a7@free-electrons.com> (raw) In-Reply-To: <113811b6-79a4-9c66-d302-add9fb0c5b1a-5wv7dgnIgG8@public.gmane.org> Hello, On Fri, 6 Jan 2017 14:44:56 +0000, Robin Murphy wrote: > >> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT > >> + dma_addr_t dma_addr = > >> + rx_desc->pp22.buf_phys_addr_key_hash & DMA_BIT_MASK(40); > >> + phys_addr_t phys_addr = > >> + dma_to_phys(port->dev->dev.parent, dma_addr); > > Ugh, this looks bogus. dma_to_phys(), in the arm64 case at least, is > essentially a SWIOTLB internal helper function which has to be > implemented in architecture code because reasons. Calling it from a > driver is almost certainly wrong (it doesn't even exist on most > architectures). Besides, if this is really a genuine dma_addr_t obtained > from a DMA API call, you cannot infer it to be related to a CPU physical > address, or convertible to one at all. So do you have a better suggestion? The descriptors only have enough space to store a 40-bit virtual address, which is not enough to fit the virtual addresses used by Linux for SKBs. This is why I'm instead relying on the fact that the descriptors can store the 40-bit physical address, and convert it back to a virtual address, which should be fine on ARM64 because the entire physical memory is part of the kernel linear mapping. > >> + return (unsigned long)phys_to_virt(phys_addr); > >> +#else > >> + return rx_desc->pp22.buf_cookie_misc & DMA_BIT_MASK(40); > >> +#endif > > > > I'm not sure that's the best way of selecting the difference. > > Given that CONFIG_ARCH_DMA_ADDR_T_64BIT could be enabled on 32-bit LPAE > systems, indeed it definitely isn't. Russell proposal of testing the size of a virtual address pointer instead would solve this I believe, correct? Thanks, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: thomas.petazzoni@free-electrons.com (Thomas Petazzoni) To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv2 net-next 05/16] net: mvpp2: introduce PPv2.2 HW descriptors and adapt accessors Date: Fri, 3 Feb 2017 14:24:46 +0100 [thread overview] Message-ID: <20170203142446.2ee517a7@free-electrons.com> (raw) In-Reply-To: <113811b6-79a4-9c66-d302-add9fb0c5b1a@arm.com> Hello, On Fri, 6 Jan 2017 14:44:56 +0000, Robin Murphy wrote: > >> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT > >> + dma_addr_t dma_addr = > >> + rx_desc->pp22.buf_phys_addr_key_hash & DMA_BIT_MASK(40); > >> + phys_addr_t phys_addr = > >> + dma_to_phys(port->dev->dev.parent, dma_addr); > > Ugh, this looks bogus. dma_to_phys(), in the arm64 case at least, is > essentially a SWIOTLB internal helper function which has to be > implemented in architecture code because reasons. Calling it from a > driver is almost certainly wrong (it doesn't even exist on most > architectures). Besides, if this is really a genuine dma_addr_t obtained > from a DMA API call, you cannot infer it to be related to a CPU physical > address, or convertible to one at all. So do you have a better suggestion? The descriptors only have enough space to store a 40-bit virtual address, which is not enough to fit the virtual addresses used by Linux for SKBs. This is why I'm instead relying on the fact that the descriptors can store the 40-bit physical address, and convert it back to a virtual address, which should be fine on ARM64 because the entire physical memory is part of the kernel linear mapping. > >> + return (unsigned long)phys_to_virt(phys_addr); > >> +#else > >> + return rx_desc->pp22.buf_cookie_misc & DMA_BIT_MASK(40); > >> +#endif > > > > I'm not sure that's the best way of selecting the difference. > > Given that CONFIG_ARCH_DMA_ADDR_T_64BIT could be enabled on 32-bit LPAE > systems, indeed it definitely isn't. Russell proposal of testing the size of a virtual address pointer instead would solve this I believe, correct? Thanks, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
next prev parent reply other threads:[~2017-02-03 13:24 UTC|newest] Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-12-28 16:46 [PATCHv2 net-next 00/16] net: mvpp2: add basic support for PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni [not found] ` <1482943592-12556-1-git-send-email-thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 2016-12-28 16:46 ` [PATCHv2 net-next 01/16] dt-bindings: net: update Marvell PPv2 binding for PPv2.2 support Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni [not found] ` <1482943592-12556-2-git-send-email-thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 2017-01-03 20:18 ` Rob Herring 2017-01-03 20:18 ` Rob Herring 2017-02-02 16:56 ` Thomas Petazzoni 2017-02-02 16:56 ` Thomas Petazzoni 2017-02-03 16:48 ` Russell King - ARM Linux 2017-02-03 16:48 ` Russell King - ARM Linux 2017-02-14 14:25 ` Thomas Petazzoni 2017-02-14 14:25 ` Thomas Petazzoni [not found] ` <20170214152503.602878cb-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 2017-02-21 10:12 ` Thomas Petazzoni 2017-02-21 10:12 ` Thomas Petazzoni 2017-01-07 9:32 ` Russell King - ARM Linux 2017-01-07 9:32 ` Russell King - ARM Linux 2017-02-02 16:44 ` Thomas Petazzoni 2017-02-02 16:44 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 02/16] net: mvpp2: add and use accessors for TX/RX descriptors Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 03/16] net: mvpp2: add hw_version field in "struct mvpp2" Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 07/16] net: mvpp2: adapt the mvpp2_rxq_*_pool_set functions to PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 14/16] net: mvpp2: adapt rxq distribution " Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 16/16] net: mvpp2: finally add the PPv2.2 compatible string Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 17:06 ` [PATCHv2 net-next 00/16] net: mvpp2: add basic support for PPv2.2 David Miller 2016-12-28 17:06 ` David Miller [not found] ` <20161228.120644.1166014191192724301.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org> 2016-12-28 21:08 ` Thomas Petazzoni 2016-12-28 21:08 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 04/16] net: mvpp2: introduce an intermediate union for the TX/RX descriptors Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 05/16] net: mvpp2: introduce PPv2.2 HW descriptors and adapt accessors Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2017-01-06 14:29 ` Russell King - ARM Linux 2017-01-06 14:29 ` Russell King - ARM Linux 2017-01-06 14:44 ` Robin Murphy 2017-01-06 14:44 ` Robin Murphy [not found] ` <113811b6-79a4-9c66-d302-add9fb0c5b1a-5wv7dgnIgG8@public.gmane.org> 2017-02-03 13:24 ` Thomas Petazzoni [this message] 2017-02-03 13:24 ` Thomas Petazzoni 2017-02-03 14:05 ` Robin Murphy 2017-02-03 14:05 ` Robin Murphy [not found] ` <231514f4-2e35-8bde-4469-aada833635aa-5wv7dgnIgG8@public.gmane.org> 2017-02-03 15:02 ` Thomas Petazzoni 2017-02-03 15:02 ` Thomas Petazzoni [not found] ` <20170203160227.08b40c58-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 2017-02-03 16:31 ` Robin Murphy 2017-02-03 16:31 ` Robin Murphy 2017-02-03 15:54 ` Russell King - ARM Linux 2017-02-03 15:54 ` Russell King - ARM Linux 2017-02-04 13:59 ` Thomas Petazzoni 2017-02-04 13:59 ` Thomas Petazzoni 2017-02-06 12:43 ` David Laight 2017-02-06 12:43 ` David Laight 2017-02-06 12:43 ` David Laight 2016-12-28 16:46 ` [PATCHv2 net-next 06/16] net: mvpp2: adjust the allocation/free of BM pools for PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2017-01-06 14:32 ` Russell King - ARM Linux 2017-01-06 14:32 ` Russell King - ARM Linux 2016-12-28 16:46 ` [PATCHv2 net-next 08/16] net: mvpp2: adapt mvpp2_defaults_set() to PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 09/16] net: mvpp2: adjust mvpp2_{rxq,txq}_init for PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 09/16] net: mvpp2: adjust mvpp2_{rxq, txq}_init " Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 10/16] net: mvpp2: handle register mapping and access " Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2017-01-06 14:46 ` Russell King - ARM Linux 2017-01-06 14:46 ` Russell King - ARM Linux [not found] ` <20170106144648.GE14217-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> 2017-03-02 8:45 ` Thomas Petazzoni 2017-03-02 8:45 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 11/16] net: mvpp2: handle misc PPv2.1/PPv2.2 differences Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2017-01-07 9:38 ` Russell King - ARM Linux 2017-01-07 9:38 ` Russell King - ARM Linux [not found] ` <20170107093834.GJ14217-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> 2017-01-07 20:10 ` Russell King - ARM Linux 2017-01-07 20:10 ` Russell King - ARM Linux 2017-02-14 14:53 ` Thomas Petazzoni 2017-02-14 14:53 ` Thomas Petazzoni 2017-01-07 11:03 ` Russell King - ARM Linux 2017-01-07 11:03 ` Russell King - ARM Linux 2017-01-07 12:12 ` Marcin Wojtas 2017-01-07 12:12 ` Marcin Wojtas [not found] ` <CAPv3WKeQ=fj2cKPyJ2NqCaAv55cOyWodujKwj3-v5iCrDYNcmA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2017-01-07 13:50 ` Russell King - ARM Linux 2017-01-07 13:50 ` Russell King - ARM Linux 2017-01-07 13:50 ` Russell King - ARM Linux 2016-12-28 16:46 ` [PATCHv2 net-next 12/16] net: mvpp2: add AXI bridge initialization for PPv2.2 Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 13/16] net: mvpp2: rework RXQ interrupt group " Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni 2016-12-28 16:46 ` [PATCHv2 net-next 15/16] net: mvpp2: add support for an additional clock needed " Thomas Petazzoni 2016-12-28 16:46 ` Thomas Petazzoni [not found] ` <1482943592-12556-16-git-send-email-thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> 2017-01-07 9:29 ` Russell King - ARM Linux 2017-01-07 9:29 ` Russell King - ARM Linux
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