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For LS1046a and LS1043a v1.1, the MSI controller has 4 MSIRs and 4 GIC SPI interrupts which can be associated with different Core. So we can support affinity to improve the performance. The MSI message data is a byte for Layerscape MSI. 7 6 5 4 3 2 1 0 | - | IBS | SRS | SRS bit0-1 is to select a MSIR which is associated with a CPU. IBS bit2-6 of ls1046, bit2-4 of ls1043a v1.1 is to select bit of the MSIR. With affinity, only bits of MSIR0(srs=0 cpu0) are available. All other bits of the MSIR1-3(cpu1-3) are reserved. The MSI hwirq always equals bit index of the MSIR0. When changing affinity, MSI message data will be appended corresponding SRS then MSI will be moved to the corresponding core. But in affinity mode, there is only 8 MSI interrupts for a controller of LS1043a v1.1. It cannot meet the requirement of the some PCIe devices such as 4 ports Ethernet card. In contrast, without affinity, all MSIRs can be used for core 0, the MSI interrupts can up to 32. So the parameter is added to control affinity mode. "lsmsi=no-affinity" will disable affinity and increase MSI interrupt number. Signed-off-by: Minghuan Lian <Minghuan.Lian@nxp.com> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.