Add support for the msi-address-64 property of a PCI node. This property
specifies the PCI address of MSIIR (message signaled interrupt index
register).
In commit 3da34aae ("powerpc/fsl: Support unique MSI addresses per PCIe Root
Complex"), the msi_addr_hi/msi_addr_lo fields of struct fsl_msi were redefined
from an actual address to just an offset, but the fields were not renamed
accordingly. These fields are replace with a single field, msiir_offset,
to reflect the new meaning.
Signed-off-by: Timur Tabi <ti...@freescale.com>
---
This patch is necessary, but not sufficient, for MSI support under the
Freescale hypervisor. Future patches will add full support.
.../devicetree/bindings/powerpc/fsl/msi-pic.txt | 42 ++++++++++++++++++++
arch/powerpc/sysdev/fsl_msi.c | 20 +++++++---
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 70558c3..5d586e1 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 1cca251..e5c344d 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 624580c..1313abb 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];
--
1.7.3.4
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