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Diffstat (limited to 'qemu/docs/specs/edu.txt')
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diff --git a/qemu/docs/specs/edu.txt b/qemu/docs/specs/edu.txt deleted file mode 100644 index 7f8146780..000000000 --- a/qemu/docs/specs/edu.txt +++ /dev/null @@ -1,110 +0,0 @@ - -EDU device -========== - -Copyright (c) 2014-2015 Jiri Slaby - -This document is licensed under the GPLv2 (or later). - -This is an educational device for writing (kernel) drivers. Its original -intention was to support the Linux kernel lectures taught at the Masaryk -University. Students are given this virtual device and are expected to write a -driver with I/Os, IRQs, DMAs and such. - -The devices behaves very similar to the PCI bridge present in the COMBO6 cards -developed under the Liberouter wings. Both PCI device ID and PCI space is -inherited from that device. - -Command line switches: - -device edu[,dma_mask=mask] - - dma_mask makes the virtual device work with DMA addresses with the given - mask. For educational purposes, the device supports only 28 bits (256 MiB) - by default. Students shall set dma_mask for the device in the OS driver - properly. - -PCI specs ---------- - -PCI ID: 1234:11e8 - -PCI Region 0: - I/O memory, 1 MB in size. Users are supposed to communicate with the card - through this memory. - -MMIO area spec --------------- - -Only size == 4 accesses are allowed for addresses < 0x80. size == 4 or -size == 8 for the rest. - -0x00 (RO) : identification (0xRRrr00edu) - RR -- major version - rr -- minor version - -0x04 (RW) : card liveness check - It is a simple value inversion (~ C operator). - -0x08 (RW) : factorial computation - The stored value is taken and factorial of it is put back here. - This happens only after factorial bit in the status register (0x20 - below) is cleared. - -0x20 (RW) : status register, bitwise OR - 0x01 -- computing factorial (RO) - 0x80 -- raise interrupt 0x01 after finishing factorial computation - -0x24 (RO) : interrupt status register - It contains values which raised the interrupt (see interrupt raise - register below). - -0x60 (WO) : interrupt raise register - Raise an interrupt. The value will be put to the interrupt status - register (using bitwise OR). - -0x64 (WO) : interrupt acknowledge register - Clear an interrupt. The value will be cleared from the interrupt - status register. This needs to be done from the ISR to stop - generating interrupts. - -0x80 (RW) : DMA source address - Where to perform the DMA from. - -0x88 (RW) : DMA destination address - Where to perform the DMA to. - -0x90 (RW) : DMA transfer count - The size of the area to perform the DMA on. - -0x98 (RW) : DMA command register, bitwise OR - 0x01 -- start transfer - 0x02 -- direction (0: from RAM to EDU, 1: from EDU to RAM) - 0x04 -- raise interrupt 0x100 after finishing the DMA - -IRQ controller --------------- -An IRQ is generated when written to the interrupt raise register. The value -appears in interrupt status register when the interrupt is raised and has to -be written to the interrupt acknowledge register to lower it. - -DMA controller --------------- -One has to specify, source, destination, size, and start the transfer. One -4096 bytes long buffer at offset 0x40000 is available in the EDU device. I.e. -one can perform DMA to/from this space when programmed properly. - -Example of transferring a 100 byte block to and from the buffer using a given -PCI address 'addr': -addr -> DMA source address -0x40000 -> DMA destination address -100 -> DMA transfer count -1 -> DMA command register -while (DMA command register & 1) - ; - -0x40000 -> DMA source address -addr+100 -> DMA destination address -100 -> DMA transfer count -3 -> DMA command register -while (DMA command register & 1) - ; |