diff options
| -rw-r--r-- | Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt | 42 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/fsl_msi.c | 20 | ||||
| -rw-r--r-- | arch/powerpc/sysdev/fsl_msi.h | 3 |
3 files changed, 57 insertions, 8 deletions
diff --git a/Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt b/Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt index 70558c3f3682..5d586e1ccaf5 100644 --- a/Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt +++ b/Documentation/devicetree/bindings/powerpc/fsl/msi-pic.txt @@ -25,6 +25,16 @@ Required properties: are routed to IPIC, and for 85xx/86xx cpu the interrupts are routed to MPIC. +Optional properties: +- msi-address-64: 64-bit PCI address of the MSIIR register. The MSIIR register + is used for MSI messaging. The address of MSIIR in PCI address space is + the MSI message address. + + This property may be used in virtualized environments where the hypervisor + has created an alternate mapping for the MSIR block. See below for an + explanation. + + Example: msi@41600 { compatible = "fsl,mpc8610-msi", "fsl,mpic-msi"; @@ -41,3 +51,35 @@ Example: 0xe7 0>; interrupt-parent = <&mpic>; }; + +The Freescale hypervisor and msi-address-64 +------------------------------------------- +Normally, PCI devices have access to all of CCSR via an ATMU mapping. The +Freescale MSI driver calculates the address of MSIIR (in the MSI register +block) and sets that address as the MSI message address. + +In a virtualized environment, the hypervisor may need to create an IOMMU +mapping for MSIIR. The Freescale ePAPR hypervisor has this requirement +because of hardware limitations of the Peripheral Access Management Unit +(PAMU), which is currently the only IOMMU that the hypervisor supports. +The ATMU is programmed with the guest physical address, and the PAMU +intercepts transactions and reroutes them to the true physical address. + +In the PAMU, each PCI controller is given only one primary window. The +PAMU restricts DMA operations so that they can only occur within a window. +Because PCI devices must be able to DMA to memory, the primary window must +be used to cover all of the guest's memory space. + +PAMU primary windows can be divided into 256 subwindows, and each +subwindow can have its own address mapping ("guest physical" to "true +physical"). However, each subwindow has to have the same alignment, which +means they cannot be located at just any address. Because of these +restrictions, it is usually impossible to create a 4KB subwindow that +covers MSIIR where it's normally located. + +Therefore, the hypervisor has to create a subwindow inside the same +primary window used for memory, but mapped to the MSIR block (where MSIIR +lives). The first subwindow after the end of guest memory is used for +this. The address specified in the msi-address-64 property is the PCI +address of MSIIR. The hypervisor configures the PAMU to map that address to +the true physical address of MSIIR. diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c index 1cca25146b1f..e5c344d336ea 100644 --- a/arch/powerpc/sysdev/fsl_msi.c +++ b/arch/powerpc/sysdev/fsl_msi.c @@ -30,7 +30,7 @@ LIST_HEAD(msi_head); struct fsl_msi_feature { u32 fsl_pic_ip; - u32 msiir_offset; + u32 msiir_offset; /* Offset of MSIIR, relative to start of MSIR bank */ }; struct fsl_msi_cascade_data { @@ -126,10 +126,19 @@ static void fsl_compose_msi_msg(struct pci_dev *pdev, int hwirq, { struct fsl_msi *msi_data = fsl_msi_data; struct pci_controller *hose = pci_bus_to_host(pdev->bus); - u64 base = fsl_pci_immrbar_base(hose); + u64 address; /* Physical address of the MSIIR */ + int len; + const u64 *reg; + + /* If the msi-address-64 property exists, then use it */ + reg = of_get_property(hose->dn, "msi-address-64", &len); + if (reg && (len == sizeof(u64))) + address = be64_to_cpup(reg); + else + address = fsl_pci_immrbar_base(hose) + msi_data->msiir_offset; - msg->address_lo = msi_data->msi_addr_lo + lower_32_bits(base); - msg->address_hi = msi_data->msi_addr_hi + upper_32_bits(base); + msg->address_lo = lower_32_bits(address); + msg->address_hi = upper_32_bits(address); msg->data = hwirq; @@ -359,8 +368,7 @@ static int __devinit fsl_of_msi_probe(struct platform_device *dev) msi->irqhost->host_data = msi; - msi->msi_addr_hi = 0x0; - msi->msi_addr_lo = features->msiir_offset + (res.start & 0xfffff); + msi->msiir_offset = features->msiir_offset + (res.start & 0xfffff); rc = fsl_msi_init_allocator(msi); if (rc) { diff --git a/arch/powerpc/sysdev/fsl_msi.h b/arch/powerpc/sysdev/fsl_msi.h index 624580c252d7..1313abbc5200 100644 --- a/arch/powerpc/sysdev/fsl_msi.h +++ b/arch/powerpc/sysdev/fsl_msi.h @@ -28,8 +28,7 @@ struct fsl_msi { unsigned long cascade_irq; - u32 msi_addr_lo; - u32 msi_addr_hi; + u32 msiir_offset; /* Offset of MSIIR, relative to start of CCSR */ void __iomem *msi_regs; u32 feature; int msi_virqs[NR_MSI_REG]; |