From: Christoph Hellwig <hch@infradead.org>
To: Imre Kaloz <kaloz@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 21/38] MIPS: SGI-IP27: route XBridge and PIC DMA through the 32-bit window
Date: Mon, 5 Oct 2026 01:39:34 -0700 [thread overview]
Message-ID: <asNiRoPpv6dkAFD4@infradead.org> (raw)
In-Reply-To: <cce203c61386970826873f87cc9d0e6c732c3a53.1790857966.git.kaloz@kernel.org>
On Thu, Oct 01, 2026 at 06:11:56PM +0200, Imre Kaloz wrote:
> XBridge does not honour the SN0-style 64-bit direct-mapped DMA address:
> commands complete but no data moves. PIC moves no data either. Route
> both through the 2GB 32-bit window and cap bus_dma_limit at its top, so
> SWIOTLB bounces anything above it. PIC is flagged once a following
> patch enumerates it.
>
> Only XBridge (part 0xd002) is flagged; a Bridge (0xc002) behind a Hub
> keeps the 64-bit direct map. The 64MB bounce pool comes from node 0
> whenever DRAM passes 2GB, on Hub any multi-node machine. A PIC bus in
> PCI-X mode takes the window too; IRIX does not.
It's been a while, but IIRC XBridge also support 64-bit direct-mapped
DMA addresses, just differently.
If you find a late 2.4 or early 2.6 kernel, it comes with an open source
copy of the IRIX-style PCI code under arch/ia64/ that also includes the
older chips never used on Altix. It might be worth to take a look at
that for clues.
next prev parent reply other threads:[~2026-10-05 8:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-01 16:11 [PATCH 00/38] MIPS: SGI-IP27: add support for the IP35 (Bedrock hub) machines Imre Kaloz
2026-10-01 16:11 ` [PATCH 01/38] MIPS: Xtalk: guard the widget identification table from assembly Imre Kaloz
2026-10-01 16:11 ` [PATCH 02/38] MIPS: SGI-IP27: dump the NMI save areas the CPU scan recorded Imre Kaloz
2026-10-01 16:11 ` [PATCH 03/38] MIPS: SGI-IP27: add REMOTE_HUB_PI_S()/REMOTE_HUB_PI_L() Imre Kaloz
2026-10-01 16:11 ` [PATCH 04/38] MIPS: SGI-IP27: detect Bedrock hubs at boot Imre Kaloz
2026-10-01 16:11 ` [PATCH 05/38] MIPS: SGI-IP27: widen Kconfig for the Bedrock-based machines Imre Kaloz
2026-10-01 16:11 ` [PATCH 06/38] MIPS: SGI-IP27: fold the dead SN1 arm out of klconfig.h Imre Kaloz
2026-10-01 16:11 ` [PATCH 07/38] MIPS: SGI-IP27: choose the node address layout at runtime Imre Kaloz
2026-10-01 16:11 ` [PATCH 08/38] MIPS: SGI-IP27: add the Bedrock hub register windows Imre Kaloz
2026-10-01 16:11 ` [PATCH 09/38] MIPS: SGI-IP27: decode a Bedrock hub's node id and system size Imre Kaloz
2026-10-01 16:11 ` [PATCH 10/38] MIPS: SGI-IP27: put a Bedrock hub's boot CPU in slot 0 Imre Kaloz
2026-10-01 16:11 ` [PATCH 11/38] MIPS: SGI-IP27: lay out node memory in 1GB banks on Bedrock hubs Imre Kaloz
2026-10-01 16:11 ` [PATCH 12/38] MIPS: SGI-IP27: reserve the bottom 64MB of node 0 " Imre Kaloz
2026-10-01 16:11 ` [PATCH 13/38] MIPS: SGI-IP27: route interrupt masks and slices through both PIs Imre Kaloz
2026-10-01 16:11 ` [PATCH 14/38] MIPS: SGI-IP27: address a CPU's own PI for NMI, IPI and RT counter Imre Kaloz
2026-10-01 16:11 ` [PATCH 15/38] MIPS: SGI-IP27: take a CPU's node from the CPU table in per_cpu_init() Imre Kaloz
2026-10-01 16:11 ` [PATCH 16/38] MIPS: SGI-IP27: resolve the mapped-kernel node shift at runtime Imre Kaloz
2026-10-01 16:11 ` [PATCH 17/38] MIPS: SGI-IP27: load the kernel at node offset 0x40000 Imre Kaloz
2026-10-01 16:11 ` [PATCH 18/38] MIPS: SGI-IP27: xbow_probe(): recognize KLTYPE_PBRICK_XBOW Imre Kaloz
2026-10-01 16:11 ` [PATCH 19/38] MIPS: ip27_defconfig: enable the IOC3 MFD, its cell drivers and tg3 Imre Kaloz
2026-10-01 16:11 ` [PATCH 20/38] net: ethernet: sgi: ioc3-eth: apply the DMA attributes only to 64-bit addresses Imre Kaloz
2026-10-01 16:11 ` [PATCH 21/38] MIPS: SGI-IP27: route XBridge and PIC DMA through the 32-bit window Imre Kaloz
2026-10-05 8:39 ` Christoph Hellwig [this message]
2026-10-05 13:15 ` Imre Kaloz
2026-10-01 16:11 ` [PATCH 22/38] MIPS: SGI-IP27: recognize the PXBow crossbar Imre Kaloz
2026-10-01 16:11 ` [PATCH 23/38] MIPS: PCI: xtalk-bridge: recognize the PIC widget's 64-bit-only registers Imre Kaloz
2026-10-01 16:11 ` [PATCH 24/38] MIPS: PCI: xtalk-bridge: match PIC's register-level differences Imre Kaloz
2026-10-01 16:12 ` [PATCH 25/38] rtc: m48t35: support the SGI IP35 timekeeper's 1968 year base Imre Kaloz
2026-10-01 16:12 ` [PATCH 26/38] mfd: ioc3: add support for IOC4 Imre Kaloz
2026-10-01 16:12 ` [PATCH 27/38] MIPS: SGI-IP27: dispatch the early console between IOC3 and IOC4 Imre Kaloz
2026-10-01 16:12 ` [PATCH 28/38] MIPS: SGI-IP27: add L1 system controller support Imre Kaloz
2026-10-01 16:12 ` [PATCH 29/38] MIPS: SGI-IP27: wire the L1 into reset and the Ethernet address Imre Kaloz
2026-10-01 16:12 ` [PATCH 30/38] MIPS: PCI: xtalk-bridge: take the board part number from the L1 Imre Kaloz
2026-10-01 16:12 ` [PATCH 31/38] mfd: ioc3: add IP34 system-board entry to ioc3_infos[] Imre Kaloz
2026-10-02 10:02 ` Lee Jones
2026-10-02 10:29 ` Imre Kaloz
2026-10-01 16:12 ` [PATCH 32/38] net: ethernet: sgi: ioc3-eth: fall back to the platform MAC address Imre Kaloz
2026-10-01 16:12 ` [PATCH 33/38] MIPS: SGI-IP27: don't register a w1 master on an XBridge or PIC Imre Kaloz
2026-10-01 16:12 ` [PATCH 34/38] MIPS: SGI-IP27: report a Bedrock machine as SGI IP35 Imre Kaloz
2026-10-01 16:12 ` [PATCH 35/38] MIPS: SGI-IP27: identify the machine by the L1 brick type Imre Kaloz
2026-10-01 16:12 ` [PATCH 36/38] MIPS: SGI-IP27: register the Odyssey graphics widget Imre Kaloz
2026-10-01 16:12 ` [PATCH 37/38] MIPS: SGI-IP27: take the console from the KLCONFIG header on IP35 Imre Kaloz
2026-10-01 16:12 ` [PATCH 38/38] MIPS: SGI-IP27: give each CPU its own topology package id Imre Kaloz
2026-10-02 15:46 ` [PATCH 00/38] MIPS: SGI-IP27: add support for the IP35 (Bedrock hub) machines Thomas Bogendoerfer
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