在ARM的Cortex A9处理器间Interrrupts（软件生成的Linux的中断（ARM）如何写一个处理程序？） [英] Inter processor Interrrupts in ARM cortex A9 ( How To write an handler for Software generated Interrupt ( ARM) in Linux? )

问题描述

我看了，在ARM的软件产生的中断用作处理器间中断。我还可以看到，那些中断5已经在使用。我也知道，ARM提供16软件产生的中断。

在我的应用程序正在运行在ARM的内核皮质和Linux上其他的裸机应用。我想从运行裸机应用程序是运行Linux核心的核心服务器通信的一些数据。我打算将数据复制到芯片上的内存（这是共享），我将触发核心（运行Linux）的一个SGI，表明一些数据可供它来处理。现在，我能够从核心生成SGI（运行裸机应用程序）。但是对于处理在Linux方面的中断，我不知道在SGI IRQ编号这是免费的，我也没把握是否可以直接使用的IRQ号（一般SGI从0-15）。没有任何一个有一个想法，如何写在Linux中对SGI的处理程序？

编辑：这是上面的文字进行重新措辞，因为这个问题被关闭 SSCE原因。皮质-A处理器在多CPU系统中使用。一个ARM的通用中断控制器的（GIC）监测所有全局中断并将它们分派到一个特定的CPU。为了让各个CPU信号对方，一个的软件产生的中断的（SGI）是由一个核心到另一个发送;这里采用的外围私人中断的（PPI）。这个问题是，

  

如何实现可接收SGI作为PPI Linux内核驱动程序？

解决方案

  

没有任何一个有一个想法，如何写在Linux中对SGI的处理程序？

由于你没有给Linux版本，我会假设你有最新的（或至少最近的）工作。 ARM的GIC有<一个href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/arm/gic.txt\"相对=nofollow>设备树的绑定的。通常情况下，你需要在设备树节点指定SGI中断号，

  IPC：IPC @地址{
        兼容=公司董事会-IPC / *您的驱动器* /
        章= LT;地址范围取代;
        中断=。1 SGI 0X02取代; / * SGI是你的CPU中断。 * /
        状态=已启用;
 };
 

在第一号的中断的节表示的 PPI 的。在 SGI 的可能会是0-15之间，因为这是那里的SGI中断路由（至少在的Cortex-A5）。

然后，你可以使用 platform_get_irq（）在驱动程序中获得的 PPI 的（外围私人中断）。我猜的地址的是你希望做通信的共享内存（物理）;也许章是不恰当的，但我认为它会工作。该区域将被Linux的MMU被重新映射，你可以使用它，

 解析度= platform_get_resource（PDEV，IORESOURCE_MEM，0）;
纪念品= devm_ioremap_resource（DEV，RES）;
 

以上的地址的设备树是物理地址的十六进制值。在 platform_get_irq（）应返回的 IRQ号的，你可以用的request_irq使用（）系列函数。就在这个连接到你的日常。

编辑：不幸的是，中断低于16由Linux <一个被禁止href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/irqchip/irq-gic.c\"相对=nofollow> IRQ-gic.c 。例如，<一href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/irqchip/irq-gic.c#n282\"相对=nofollow> gic_handle_irq（） ，限制处理程序，以16和1020如果SMP之间的中断使能，那么 handle_IPI（ ）被称为感兴趣的中断。 <一href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/irqchip/irq-gic.c#n651\"相对=nofollow> gic_raise_softirq（） 可以用来产生中断信号。为了处理在 SGI 与当前的Linux，的 smp.c 需要额外的<一个href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/kernel/smp.c#n63\"相对=nofollow> 枚举ipi_msg_type 价值观和code在处理这些<一个href=\"https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/kernel/smp.c#n544\"相对=nofollow> handle_IPI（） 。它看起来像新的内核（3.14+吧？）可能会在 set_ipi_handler（）添加到的 smp.c 的做出这样的修改不必要的。

I read that the the Software generated interrupts in ARM are used as Inter-processor interrupts. I can also see that 5 of those interrupts are already in use. I also know that ARM provides 16 Software generated interrupts.

In my application i am running a bare metal application on of the ARM-cortex cores and Linux on the other. I want to communicate some data from the core running bare metal application to the core which is running Linux. I plan to copy the data to the on chip memory ( which is shared) and I will trigger a SGI on the Core ( running linux) to indicate some data is available for it to process. Now I am able to generate the SGI from the core ( running bare-metal application ). But for handling the interrupt in the linux side, I am not sure of the SGI IRQ numbers which are free and I am also not sure whether i can use the IRQ number directly ( in general SGI are from 0-15). Does any one have an idea how to write a handler for SGI in Linux?

Edit: This is a re-wording of the above text, because the question was closed for SSCE reasons. The Cortex-A CPUs are used in multi-CPU systems. An ARM generic interrupt controller (GIC) monitors all global interrupts and dispatches them to a particular CPU. In order for individual CPUs to signal each other, a software generated interrupt (SGI) is sent from one core to the other; this uses peripheral private interrupts (PPI). This question is,

How to implement a Linux kernel driver that can receive an SGI as a PPI?

解决方案

Does any one have an idea how to write a handler for SGI in Linux?

As you didn't give the Linux version, I will assume you work with the latest (or at least recent). The ARM GIC has device tree bindings. Typically, you need to specify the SGI interrupt number in a device tree node,

 ipc: ipc@address {
        compatible = "company,board-ipc"; /* Your driver */
        reg = <address range>;
        interrupts = <1 SGI 0x02>;  /* SGI is your CPU interrupt. */
        status = "enabled";
 };

The first number in the interrupt stanza denotes a PPI. The SGI will probably be between 0-15 as this is where the SGI interrupts are routed (at least on a Cortex-A5).

Then you can just use the platform_get_irq() in your driver to get the PPI (peripheral private interrupt). I guess that address is the shared memory (physical) where you wish to do the communications; maybe reg is not appropriate, but I think it will work. This area will be remapped by the Linux MMU and you can use it with,

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
mem = devm_ioremap_resource(dev, res);

The address in the device tree above is a hex value of the physical address. The platform_get_irq() should return an irq number which you can use with the request_irq() family of functions. Just connect this to your routine.

Edit: Unfortunately, interrupts below 16 are forbidden by the Linux irq-gic.c. For example, gic_handle_irq(), limits handler to interrupts between 16 and 1020. If SMP is enabled, then handle_IPI() is called for the interrupts of interest. gic_raise_softirq() can be used to signal an interrupt. To handle the SGI with the current Linux, smp.c needs additional enum ipi_msg_type values and code to handle these in handle_IPI(). It looks like newer kernels (3.14+ perhaps?) may add a set_ipi_handler() to smp.c to make such a modification unneeded.

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