Hi Shaked, In the prob function, before you are trying to do any DMA operations with your device, you should call pci_enable_device and then pci_set_master. Also you might need to map the resources of your device. Check PCI driver documentation: https://lxr.missinglinkelectronics.com/linux/Documentation/PCI/pci.rst#L199
Best regards, Yan. > On 29 Oct 2020, at 10:32 PM, Shaked Matzner <shake...@neuroblade.ai> wrote: > > Hey Peter, > Currently I have this test in the driver which allocates data, assign it to > default value config source as the BASE address of dma, dest as the physical > address which I got from dma_alloc_coherent, set the count and assign the > command to raise interrupt and read,the piece of code used is something like > this(this a test performed from the probe function of the driver) > vaddr_to = > dma_alloc_coherent(&(dev->dev), 4, &dma_handle_to, GFP_ATOMIC |GFP_KERNEL); > *((volatile int*)vaddr_to) = 0xff; > test->vaddr_to = vaddr_to; > dev_info(&(dev->dev), > "vaddr_to = %px\n", vaddr_to); > dev_info(&(dev->dev), > "dma_handle_to = %llx\n", (unsigned long long)dma_handle_to); > iowrite32(DMA_BASE, mmio + > IO_DMA_SRC); > iowrite32((u32)dma_handle_to, > mmio + IO_DMA_DST); > iowrite32(SIZE, mmio + > IO_DMA_CNT); > iowrite32(DMA_CMD | > DMA_FROM_DEV | DMA_IRQ, mmio + IO_DMA_CMD); > Where and when should the pci_set_master hould be called? > Thanks, > Shaked Matzner > > From: Peter Maydell <peter.mayd...@linaro.org> > Sent: Thursday, October 29, 2020 5:46 PM > To: Shaked Matzner <shake...@neuroblade.ai> > Cc: qemu-devel@nongnu.org > Subject: Re: simple example of pci driver with dma > > > IRONSCALES couldn't recognize this email as this is the first time you > received an email from this sender peter.mayd...@linaro.org > > [EXTERNAL] > > On Thu, 29 Oct 2020 at 14:59, Shaked Matzner wrote: > > however the value I get is still 255(0xff) and not 18(0x12) probably I've > > missed something but when the interrupt is called the transfer to the RAM > > address should be completed, however it seems like the dma_write_buffer > > function from the device does not perform any transfer. What Am I missing? > > The usual mistake is forgetting in the guest code to program the > PCI device to enable bus mastering by setting the Bus Master bit > in the Command register in the PCI config space registers for > the device. Unless you do that then all DMA attempts will fail > (same as on real h/w). In the Linux kernel the function for this > is pci_set_master(), I think. > > thanks > -- PMM > > The contents of this email message and any attachments are intended solely > for the addressee(s) and may contain confidential and/or privileged > information and may be legally protected from disclosure. If you are not the > intended recipient of this message or their agent, or if this message has > been addressed to you in error, please immediately alert the sender by reply > email and then delete this message and any attachments. If you are not the > intended recipient, you are hereby notified that any use, dissemination, > copying, or storage of this message or its attachments is strictly > prohibited. > -------------------------------------------------- Daynix Computing LTD Yan Vugenfirer, CEO Email: y...@daynix.com Phone (Israel): +972-54-4758084 Phone (USA): +1-7204776716 Phone (UK): +44-2070482938 Web: www.daynix.com
