kernel/arch/mips/include/asm/mach-generic, branch linux-5.1.y

MIPS: Allow auto-dection of ARCH_PFN_OFFSET & PHYS_OFFSET

2018-07-30T17:27:32Z

On systems where physical memory begins at a non-zero address, defining PHYS_OFFSET (which influences ARCH_PFN_OFFSET) can save us time & memory by avoiding book-keeping for pages from address zero to the start of memory. Some MIPS platforms already make use of this, but with the definition of PHYS_OFFSET being compile-time constant it hasn't been possible to enable this optimization for a kernel which may run on systems with varying physical memory base addresses. Introduce a new Kconfig option CONFIG_MIPS_AUTO_PFN_OFFSET which, when enabled, makes ARCH_PFN_OFFSET a variable & detects it from the boot memory map (which for example may have been populated from DT). The relationship with PHYS_OFFSET is reversed, with PHYS_OFFSET now being based on ARCH_PFN_OFFSET. This is because ARCH_PFN_OFFSET is used far more often, so avoiding the need for runtime calculation gives us a smaller impact on kernel text size (0.1% rather than 0.15% for 64r6el_defconfig). Signed-off-by: Paul Burton Suggested-by: Vladimir Kondratiev Patchwork: https://patchwork.linux-mips.org/patch/20048/ Cc: James Hogan Cc: Ralf Baechle Cc: linux-mips@linux-mips.org

MIPS: remove the old dma-default implementation

2018-06-24T16:27:27Z

Now unused. Signed-off-by: Christoph Hellwig Patchwork: https://patchwork.linux-mips.org/patch/19551/ Signed-off-by: Paul Burton Cc: Florian Fainelli Cc: David Daney Cc: Kevin Cernekee Cc: Jiaxun Yang Cc: Tom Bogendoerfer Cc: Huacai Chen Cc: iommu@lists.linux-foundation.org Cc: linux-mips@linux-mips.org

MIPS: remove CONFIG_DMA_COHERENT

2018-06-24T16:26:02Z

We can just check for !CONFIG_DMA_NONCOHERENT instead and simplify things a lot. Signed-off-by: Christoph Hellwig Reviewed-by: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/19530/ Signed-off-by: Paul Burton Cc: Florian Fainelli Cc: David Daney Cc: Kevin Cernekee Cc: Jiaxun Yang Cc: Tom Bogendoerfer Cc: Huacai Chen Cc: iommu@lists.linux-foundation.org Cc: linux-mips@linux-mips.org

dma-mapping: move swiotlb arch helpers to a new header

2018-01-10T15:40:54Z

phys_to_dma, dma_to_phys and dma_capable are helpers published by architecture code for use of swiotlb and xen-swiotlb only. Drivers are not supposed to use these directly, but use the DMA API instead. Move these to a new asm/dma-direct.h helper, included by a linux/dma-direct.h wrapper that provides the default linear mapping unless the architecture wants to override it. In the MIPS case the existing dma-coherent.h is reused for now as untangling it will take a bit of work. Signed-off-by: Christoph Hellwig Acked-by: Robin Murphy

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

MIPS: generic: Set RTC_ALWAYS_BCD to 0

2017-06-28T10:22:41Z

Drivers for the mc146818 RTC generally check control registers to determine whether a value is encoded as binary or as a binary coded decimal. Setting RTC_ALWAYS_BCD to 1 effectively bypasses these checks and causes drivers to always expect binary coded decimal values, regardless of control register values. This does not seem like a sane default - defaulting to 0 allows the drivers to check control registers to determine encoding type & allows the driver to work generically with both binary & BCD encodings. Set this in mach-generic/mc146818rtc.h such that the generic kernel, or platforms which don't provide a custom mc146818rtc.h, can have an RTC driver which works with both encodings. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16185/ Signed-off-by: Ralf Baechle

MIPS: Adjust MIPS64 CAC_BASE to reflect Config.K0

2016-10-06T16:02:35Z

On MIPS64 we define the default CAC_BASE as one of the xkphys regions of the virtual address space. Since the CCA is encoded in bits 61:59 of xkphys addresses, fixing CAC_BASE to any particular one prevents us from dynamically changing the CCA as we do for MIPS32 where CAC_BASE is placed within kseg0. In order to make the kernel more generic, drop the current kludge that gives CAC_BASE CCA=3 if CONFIG_DMA_NONCOHERENT is selected (disregarding CONFIG_DMA_MAYBE_COHERENT) & CCA=5 (which is not standardised by the architecture) otherwise. Instead read Config.K0 and generate the appropriate offset into xkphys, presuming that either the bootloader or early kernel code will have configured Config.K0 appropriately. This seems like the best option for a generic implementation. The ip27 spaces.h is adjusted to set its former value of CAC_BASE, since it's the only user of CAC_BASE from assembly (in its smp_slave_setup macro). This allows the generic case to focus solely on C code without breaking ip27. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14351/ Signed-off-by: Ralf Baechle

MIPS: Support per-device DMA coherence

2016-10-06T16:02:01Z

On some MIPS systems, a subset of devices may have DMA coherent with CPU caches. For example in systems including a MIPS I/O Coherence Unit (IOCU), some devices may be connected to that IOCU whilst others are not. Prior to this patch, we have a plat_device_is_coherent() function but no implementation which does anything besides return a global true or false, optionally chosen at runtime. For devices such as those described above this is insufficient. Fix this by tracking DMA coherence on a per-device basis with a dma_coherent field in struct dev_archdata. Setting this from arch_setup_dma_ops() takes care of devices which set the dma-coherent property via device tree, and any PCI devices beneath a bridge described in DT, automatically. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/14349/ Signed-off-by: Ralf Baechle

MIPS: Sanitise coherentio semantics

2016-10-06T16:01:28Z

The coherentio variable has previously been used as a boolean value, indicating whether the user specified that coherent I/O should be enabled or disabled. It failed to take into account the case where the user does not specify any preference, in which case it makes sense that we should default to coherent I/O if the hardware supports it (hw_coherentio is non-zero). Introduce an enum to clarify the 3 different values of coherentio & use it throughout the code, modifying plat_device_is_coherent() & r4k_cache_init() to take into account the default case. Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Cc: Paul Burton Patchwork: https://patchwork.linux-mips.org/patch/14347/ Signed-off-by: Ralf Baechle

MIPS: Squash lines for simple wrapper functions

2016-10-04T14:13:57Z

Remove unneeded variables and assignments. Signed-off-by: Masahiro Yamada Cc: Boris Brezillon Cc: Brian Norris Cc: Michal Hocko Cc: Andrew Morton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14260/ Signed-off-by: Ralf Baechle