[PATCH] PCI/MSI: pci-xgene-msi: Enable MSI support in ACPI boot for X-Gene v1

On Mon, Feb 22, 2016 at 8:03 AM, Bjorn Helgaas [off-list ref] wrote:

On Sat, Feb 20, 2016 at 1:47 PM, Duc Dang [off-list ref] wrote:

quoted

On Tue, Feb 9, 2016 at 5:56 PM, Duc Dang [off-list ref] wrote:

quoted

This patch makes pci-xgene-msi driver ACPI-aware and provides
MSI capability for X-Gene v1 PCIe controllers in ACPI boot mode.

Hi Bjorn,

Are you planning to take this patch into your tree?

Sorry, I haven't had a chance to look at this yet.  I had a sick
daughter last week, so I'm even farther behind than usual.

Hi Bjorn,

I hope your daughter is doing well.

When I get to it, I'll be asking questions like:

  - Does this correspond to some analogous x86 code?

I am not aware of any x86 code similar to this.

  - Is there something unique about arm64 or X-Gene that means it
needs special code?

The MSI controller on X-Gene v1 is a separate IP block. pci-xgene-msi
is a separate X-Gene v1 specific driver that provides MSI capability
for X-Gene v1 PCIe controllers. We already have device-tree version of
this driver. So the purpose of this patch is to make the driver can be
discovered and loaded when booting with ACPI mode.

Regards,
Duc Dang.

I don't really understand the arm64/ACPI strategy yet, so I'll be
looking first for generic solutions that work across x86/ia64/arm64,
and justifications for the inevitable exceptions.

quoted

quoted

Signed-off-by: Duc Dang <redacted>
---
 drivers/pci/host/pci-xgene-msi.c | 35 ++++++++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/host/pci-xgene-msi.c b/drivers/pci/host/pci-xgene-msi.c
index a6456b5..466aa93 100644
--- a/drivers/pci/host/pci-xgene-msi.c
+++ b/drivers/pci/host/pci-xgene-msi.c

@@ -24,6 +24,7 @@
 #include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/of_pci.h>
+#include <linux/acpi.h>

 #define MSI_IR0                        0x000000
 #define MSI_INT0               0x800000

@@ -39,7 +40,7 @@ struct xgene_msi_group {
 };

 struct xgene_msi {
-       struct device_node      *node;
+       struct fwnode_handle    *fwnode;
        struct irq_domain       *inner_domain;
        struct irq_domain       *msi_domain;
        u64                     msi_addr;

@@ -249,6 +250,13 @@ static const struct irq_domain_ops msi_domain_ops = {
        .free   = xgene_irq_domain_free,
 };

+#ifdef CONFIG_ACPI
+static struct fwnode_handle *xgene_msi_get_fwnode(struct device *dev)
+{
+       return xgene_msi_ctrl.fwnode;
+}
+#endif
+
 static int xgene_allocate_domains(struct xgene_msi *msi)
 {
        msi->inner_domain = irq_domain_add_linear(NULL, NR_MSI_VEC,

@@ -256,7 +264,7 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
        if (!msi->inner_domain)
                return -ENOMEM;

-       msi->msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(msi->node),
+       msi->msi_domain = pci_msi_create_irq_domain(msi->fwnode,
                                                    &xgene_msi_domain_info,
                                                    msi->inner_domain);

@@ -265,6 +273,9 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
                return -ENOMEM;
        }

+#ifdef CONFIG_ACPI
+       pci_msi_register_fwnode_provider(&xgene_msi_get_fwnode);
+#endif
        return 0;
 }

@@ -473,6 +484,13 @@ static const struct of_device_id xgene_msi_match_table[] = {
        {},
 };

+#ifdef CONFIG_ACPI
+static const struct acpi_device_id xgene_msi_acpi_ids[] = {
+       {"APMC0D0E", 0},
+       { },
+};
+#endif
+
 static int xgene_msi_probe(struct platform_device *pdev)
 {
        struct resource *res;

@@ -494,7 +512,17 @@ static int xgene_msi_probe(struct platform_device *pdev)
                goto error;
        }
        xgene_msi->msi_addr = res->start;
-       xgene_msi->node = pdev->dev.of_node;
+
+       xgene_msi->fwnode = of_node_to_fwnode(pdev->dev.of_node);
+       if (!xgene_msi->fwnode) {
+               xgene_msi->fwnode = irq_domain_alloc_fwnode(NULL);
+               if (!xgene_msi->fwnode) {
+                       dev_err(&pdev->dev, "Failed to create fwnode\n");
+                       rc = ENOMEM;
+                       goto error;
+               }
+       }
+
        xgene_msi->num_cpus = num_possible_cpus();

        rc = xgene_msi_init_allocator(xgene_msi);

@@ -571,6 +599,7 @@ static struct platform_driver xgene_msi_driver = {
        .driver = {
                .name = "xgene-msi",
                .of_match_table = xgene_msi_match_table,
+               .acpi_match_table = ACPI_PTR(xgene_msi_acpi_ids),
        },
        .probe = xgene_msi_probe,
        .remove = xgene_msi_remove,
--

1.9.1