Xen: ARM: Add support for mapping platform device mmio

Add a bus_notifier for platform bus device in order to map the device
mmio regions when DOM0 booting with ACPI.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Tested-by: Julien Grall <julien.grall@arm.com>

2 files changed, 154 insertions, 0 deletions

diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 030e91b38e32..8feab810aed9 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -10,6 +10,7 @@ CFLAGS_features.o			:= $(nostackp)
 CFLAGS_efi.o                            += -fshort-wchar
 LDFLAGS                                 += $(call ld-option, --no-wchar-size-warning)
 
+dom0-$(CONFIG_ARM64) += arm-device.o
 dom0-$(CONFIG_PCI) += pci.o
 dom0-$(CONFIG_USB_SUPPORT) += dbgp.o
 dom0-$(CONFIG_XEN_ACPI) += acpi.o $(xen-pad-y)
diff --git a/drivers/xen/arm-device.c b/drivers/xen/arm-device.c
new file mode 100644
index 000000000000..b918e8ed5084
--- /dev/null
+++ b/drivers/xen/arm-device.c
@@ -0,0 +1,153 @@
+/*
+ * Copyright (c) 2015, Linaro Limited, Shannon Zhao
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
+#include <xen/xen.h>
+#include <xen/page.h>
+#include <xen/interface/memory.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+
+static int xen_unmap_device_mmio(const struct resource *resources,
+                                 unsigned int count)
+{
+        unsigned int i, j, nr;
+        int rc = 0;
+        const struct resource *r;
+        struct xen_remove_from_physmap xrp;
+
+        for (i = 0; i < count; i++) {
+                r = &resources[i];
+                nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
+                if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
+                        continue;
+
+                for (j = 0; j < nr; j++) {
+                        xrp.domid = DOMID_SELF;
+                        xrp.gpfn = XEN_PFN_DOWN(r->start) + j;
+                        rc = HYPERVISOR_memory_op(XENMEM_remove_from_physmap,
+                                                  &xrp);
+                        if (rc)
+                                return rc;
+                }
+        }
+
+        return rc;
+}
+
+static int xen_map_device_mmio(const struct resource *resources,
+                               unsigned int count)
+{
+        unsigned int i, j, nr;
+        int rc = 0;
+        const struct resource *r;
+        xen_pfn_t *gpfns;
+        xen_ulong_t *idxs;
+        int *errs;
+        struct xen_add_to_physmap_range xatp;
+
+        for (i = 0; i < count; i++) {
+                r = &resources[i];
+                nr = DIV_ROUND_UP(resource_size(r), XEN_PAGE_SIZE);
+                if ((resource_type(r) != IORESOURCE_MEM) || (nr == 0))
+                        continue;
+
+                gpfns = kzalloc(sizeof(xen_pfn_t) * nr, GFP_KERNEL);
+                idxs = kzalloc(sizeof(xen_ulong_t) * nr, GFP_KERNEL);
+                errs = kzalloc(sizeof(int) * nr, GFP_KERNEL);
+                if (!gpfns || !idxs || !errs) {
+                        kfree(gpfns);
+                        kfree(idxs);
+                        kfree(errs);
+                        rc = -ENOMEM;
+                        goto unmap;
+                }
+
+                for (j = 0; j < nr; j++) {
+                        /*
+                         * The regions are always mapped 1:1 to DOM0 and this is
+                         * fine because the memory map for DOM0 is the same as
+                         * the host (except for the RAM).
+                         */
+                        gpfns[j] = XEN_PFN_DOWN(r->start) + j;
+                        idxs[j] = XEN_PFN_DOWN(r->start) + j;
+                }
+
+                xatp.domid = DOMID_SELF;
+                xatp.size = nr;
+                xatp.space = XENMAPSPACE_dev_mmio;
+
+                set_xen_guest_handle(xatp.gpfns, gpfns);
+                set_xen_guest_handle(xatp.idxs, idxs);
+                set_xen_guest_handle(xatp.errs, errs);
+
+                rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
+                kfree(gpfns);
+                kfree(idxs);
+                kfree(errs);
+                if (rc)
+                        goto unmap;
+        }
+
+        return rc;
+
+unmap:
+        xen_unmap_device_mmio(resources, i);
+        return rc;
+}
+
+static int xen_platform_notifier(struct notifier_block *nb,
+                                 unsigned long action, void *data)
+{
+        struct platform_device *pdev = to_platform_device(data);
+        int r = 0;
+
+        if (pdev->num_resources == 0 || pdev->resource == NULL)
+                return NOTIFY_OK;
+
+        switch (action) {
+        case BUS_NOTIFY_ADD_DEVICE:
+                r = xen_map_device_mmio(pdev->resource, pdev->num_resources);
+                break;
+        case BUS_NOTIFY_DEL_DEVICE:
+                r = xen_unmap_device_mmio(pdev->resource, pdev->num_resources);
+                break;
+        default:
+                return NOTIFY_DONE;
+        }
+        if (r)
+                dev_err(&pdev->dev, "Platform: Failed to %s device %s MMIO!\n",
+                        action == BUS_NOTIFY_ADD_DEVICE ? "map" :
+                        (action == BUS_NOTIFY_DEL_DEVICE ? "unmap" : "?"),
+                        pdev->name);
+
+        return NOTIFY_OK;
+}
+
+static struct notifier_block platform_device_nb = {
+        .notifier_call = xen_platform_notifier,
+};
+
+static int __init register_xen_platform_notifier(void)
+{
+        if (!xen_initial_domain() || acpi_disabled)
+                return 0;
+
+        return bus_register_notifier(&platform_bus_type, &platform_device_nb);
+}
+
+arch_initcall(register_xen_platform_notifier);