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JET60200's avatar
JET60200
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5 years ago
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A10SOC: "SPI FPGA IP"'s Interrupt Sender is "7", but in linux Device Tree "irqno" set to “26” ？Why

I'm studying an A10SOC FPGA Project from ADI.

In the QSYS Designer, there's an "INTEL FPGA SPI IP" module, its IRQ NUMBER set is to "7" (as below picture). And this spi irq connects to "f2h_irq0" of SYS_HPS.

But checking linux device tree, the "sys_spi" device says as following:


sys_spi: spi@40 {
compatible = "altr,spi-1.0";
reg = <0x00000040 0x00000020>;
interrupt-parent = <&intc>;
interrupts = <0 26 4>; // => in linux device tree, the "interrupt no" is set to 26, WHY ??.
#address-cells = <0x1>;
#size-cells = <0x0>;
};

Pls help to clarify How this "26" comes from ?

Thanks

  • Isaac_V_Intel's avatar
    Isaac_V_Intel
    5 years ago

    Hello.


    The "26" is because you have the interruption vector with 32 irq, also the irq have the 51 position. So, in the Linux case, you need to make the correct offset for the system understanding.


    Here is how the macro calculate the offset: #define BUTTON_PIO_IRQ (A10_HPS_BUTTON_PIO_IRQ + 51 - 32)


    Best regards,

    Isaac Vazquez.


2 Replies

  • Isaac_V_Intel's avatar
    Isaac_V_Intel
    Icon for Contributor rankContributor
    5 years ago

    Hello.


    The "26" is because you have the interruption vector with 32 irq, also the irq have the 51 position. So, in the Linux case, you need to make the correct offset for the system understanding.


    Here is how the macro calculate the offset: #define BUTTON_PIO_IRQ (A10_HPS_BUTTON_PIO_IRQ + 51 - 32)


    Best regards,

    Isaac Vazquez.