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</o:shapelayout></xml><![endif]--></head><body lang=KO link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>Hi Ozgur,<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>The SPI I meant was ‘shared peripheral interrupt’ of armv8 architecture.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>(the interrupt is shared among cores. The interrupt controller distributes it)<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>I’ll look into your link when I’ll be working with SPI (serial peripheral interface) later :).<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>Thank you.<o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'>Chan <o:p></o:p></span></p><p class=MsoNormal style='word-break:break-hangul'><span lang=EN-US style='font-size:10.0pt;font-family:"맑은 고딕"'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri",sans-serif'> Ozgur Kara <ozgur@goosey.org> <br><b>Sent:</b> Monday, April 11, 2022 10:10 PM<br><b>To:</b> Chan Kim <ckim@etri.re.kr>; 'qemu-discuss' <qemu-discuss@nongnu.org>; kernelnewbies@kernelnewbies.org<br><b>Subject:</b> Re: Can't understand /proc/interrupts output for GICv3 case<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><div><div><p class=MsoNormal><span lang=EN-US>Hello,<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>firstly when you say SPI so can you give some more information about your hardware?<o:p></o:p></span></p></div><div><div><p class=MsoNormal><span lang=EN-US>I think you are doing an embedded development in that case you should do some research on howto understand SPI interface under the kernel.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><div><p class=MsoNormal><span lang=EN-US>I think for example, source code of a previously written hardware using SPI bus can give you an idea. You can look at examples for example spi-based Xilinx however I think all SPI hardware is declared under /linux/drivers/spi with "spi.c". Also we see a "spi.h" header file depending on kernel headers.<o:p></o:p></span></p></div></div></div></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><div><p class=MsoNormal><span lang=EN-US>So, if you define a master mode (MOSI) then "interrupt.h" header file will be useful because must first determine free irq and these calls are defined in interrupt.h.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Please attention some kernel call:<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>- request_irq<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>- irqsave()<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>- irqrestore()<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><div><p class=MsoNormal><span lang=EN-US>and maybe check out the "Interrupt Handling" book and please read follow website:<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div></div><div><div><p class=MsoNormal><span lang=EN-US><a href="https://www.kernel.org/doc/html/v4.11/driver-api/spi.html" target="_blank">https://www.kernel.org/doc/html/v4.11/driver-api/spi.html</a><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>* Book (Understand the Linux Kernel)<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> - Section: Interrupt Handling<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Salut!<o:p></o:p></span></p></div></div><div><p class=MsoNormal><span lang=EN-US> <o:p></o:p></span></p></div></div><div><p class=MsoNormal><span lang=EN-US>11.04.2022, 16:36, "Chan Kim" <<a href="mailto:ckim@etri.re.kr">ckim@etri.re.kr</a>>:<o:p></o:p></span></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p><span lang=EN-US>Hi,<br>nobody's replying to my question.. so sad..<br>I found the kernel makes an array (actually a radix tree) of 'irq_desc's.<br>And my hwirq (SPI 15) is assigned to one of these irq_descs while processing<br>device tree.<br>In my case it was assigned irq 6 (this irq is what is called virtual irq).<br>So I registered the handler by request_irq(6,...) and the interrupt works<br>fine.<br>So now my question is : how can find my irq number (correct irq_desc number)<br>in kernel driver module?<br>I'll appreciate it if you could tell me how to do it.<br>Thank you!<br><br>Chan Kim<br> <o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal><span lang=EN-US> -----Original Message-----<br> From: Chan Kim <<a href="mailto:ckim@etri.re.kr">ckim@etri.re.kr</a>><br> Sent: Friday, April 8, 2022 1:53 PM<br> To: 'qemu-discuss' <<a href="mailto:qemu-discuss@nongnu.org">qemu-discuss@nongnu.org</a>>;<br> <a href="mailto:kernelnewbies@kernelnewbies.org">kernelnewbies@kernelnewbies.org</a><br> Subject: Can't understand /proc/interrupts output for GICv3 case<br> <br> Hello all<br> <br> I think I'm asking too many question recently but sometimes I get very big<br> help from here so please forgive me.<br> (and I think someone else can get help from this email thread) I'm doing<br> experiment for interrupt of a device called axpu on an arm64 virtual<br> machine.<br> In QEMU virtual machine, the interrupts are assigned as below.<br> (These numbers are SPI(shared peripheral interrupt) numbers, and there are<br> 16 SGI and 16 PPI before SPI, so we have to add 32 to get the INTID<br> value(hwirq number))<br> <br> static const int a15irqmap[] = {<br> [AB21Q_UART] = 1,<br> [AB21Q_RTC] = 2,<br> [AB21Q_PCIE] = 3, /* ... to 6 */<br> [AB21Q_GPIO] = 7,<br> [AB21Q_SECURE_UART] = 8,<br> [AB21Q_ACPI_GED] = 9,<br> [AB21Q_MMIO] = 16, /* ...to 16 + NUM_VIRTIO_TRANSPORTS - 1 */<br> [AB21Q_GIC_V2M] = 48, /* ...to 48 + NUM_GICV2M_SPIS - 1 */<br> [AB21Q_SMMU] = 74, /* ...to 74 + NUM_SMMU_IRQS - 1 */<br> [AB21Q_PLATFORM_BUS] = 112, /* ...to 112 + PLATFORM_BUS_NUM_IRQS -1 */<br> [AB21Q_AXPU] = 15,<br> };<br> <br> In the driver, when I do request_irq(32+15, axpu_irq_handler, IRQF_SHARED,<br> "axpu_irq", &axpu_cdev) for my device axpu, the /proc/interrupts' looks<br> like this. See the 10th item(axpu_irq).<br> <br> CPU0<br> 1: 0 GICv3 25 Level vgic<br> 3: 0 GICv3 30 Level kvm guest ptimer<br> 4: 0 GICv3 27 Level kvm guest vtimer<br> 5: 20432 GICv3 26 Level arch_timer<br> 40: 0 GICv3 106 Edge arm-smmu-v3-evtq<br> 43: 0 GICv3 109 Edge arm-smmu-v3-gerror<br> 44: 0 GICv3 34 Level rtc-pl031<br> 45: 164 GICv3 33 Level uart-pl011<br> 46: 0 GICv3 23 Level arm-pmu<br> 47: 7789 GICv3 36 Level virtio0, axpu_irq<br> 48: 0 9030000.pl061 3 Edge GPIO Key Poweroff<br> IPI0: 0 Rescheduling interrupts<br> IPI1: 0 Function call interrupts<br> IPI2: 0 CPU stop interrupts<br> IPI3: 0 CPU stop (for crash dump) interrupts<br> IPI4: 0 Timer broadcast interrupts<br> IPI5: 0 IRQ work interrupts<br> IPI6: 0 CPU wake-up interrupts<br> Err: 0<br> <br> There are two numbers. One in the first column and the other in the 4th<br> column.<br> After observing uart-pl011 driver's action(who's irq in 8th row), I found<br> the number in the first column is the one I should pass to the request_irq<br> funcion, and the second number in the 4th column is the input to the<o:p></o:p></span></p></blockquote><p><span lang=EN-US>GICv3.<o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal><span lang=EN-US> (uart was assigned SPI 1, so 32+1 = 33).<br> In my axpu driver case, I requested request_irq(47, ...) so hwirq is 47<br> but I don't know why it was assigned to GICv3 input 36.<br> Shouldn't it be 47 too? (32+15=47).<br> <br> Without fixing QEMU code(still using SPI 15), I tried doing<o:p></o:p></span></p></blockquote><p><span lang=EN-US>request_irq(15,<o:p></o:p></span></p><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><p class=MsoNormal><span lang=EN-US> axpu_irq_handler, ..) for test and this time it looks like this.(see the<br> 5th<br> row)<br> <br> CPU0<br> 1: 0 GICv3 25 Level vgic<br> 3: 0 GICv3 30 Level kvm guest ptimer<br> 4: 0 GICv3 27 Level kvm guest vtimer<br> 5: 8174 GICv3 26 Level arch_timer<br> 15: 0 GICv3 56 Edge axpu_irq<br> 40: 0 GICv3 106 Edge arm-smmu-v3-evtq<br> 43: 0 GICv3 109 Edge arm-smmu-v3-gerror<br> 44: 0 GICv3 34 Level rtc-pl031<br> 45: 175 GICv3 33 Level uart-pl011<br> 46: 0 GICv3 23 Level arm-pmu<br> 47: 7790 GICv3 36 Level virtio0<br> 48: 0 9030000.pl061 3 Edge GPIO Key Poweroff<br> IPI0: 0 Rescheduling interrupts<br> IPI1: 0 Function call interrupts<br> IPI2: 0 CPU stop interrupts<br> IPI3: 0 CPU stop (for crash dump) interrupts<br> IPI4: 0 Timer broadcast interrupts<br> IPI5: 0 IRQ work interrupts<br> IPI6: 0 CPU wake-up interrupts<br> Err: 0<br> <br> Now axpu_irq has moved to INTID 15 (as expected), but it changed to "GICv3<br> 56 Edge".<br> How is this GICv3 number is assigned? (and I guess edge trigger is the<br> default for INTID < 16. Because it's SGI..?)<br> <br> I thought I connected my device (axpu) to SPI 15 in qemu code but this<br> GICv3 input number changes according to with what number I called<br> reqeust_irq.<br> Could anyone tell me what is going on here?<br> <br> Thank you.<br> Chan Kim<o:p></o:p></span></p></blockquote></blockquote></div></div></body></html>